all 3 systems
Respiratory System
Lessons covered
Task of Respiration
Anatomy of Respiratory System
Mechanics of Breathing
Respiratory Control
Respiratory Disorders
Concepts
Task of respiration in animals
Respiration: exchange of oxygen + carbon dioxide between organism + external environment
Respiratory system supplies oxygen to cells + removes carbon dioxide
2 requirements for respiration/gas exchange
respiratory surface must be large enough for gas exchange to occur at the rate that will meet the organism’s metabolic needs
respiration must take place in a moist environment so gases are dissolved
Simple Gas Exchange: single-celled organisms rely on diffusion with cell membrane only, which only works for less complex organisms (small + less specialized)
Special Respiratory System
Skin respiration
Earthworms
skin surface is lined with many tiny blood vessels
diffusion occurs through thin, moist skin
mucus + body fluids excreted on skin
only come out in darkness/night (would evaporate in sun)
Gills
some organisms have protective coats that decrease surface area for gas exchange, need gills
Gills: feathery tissue structures with numerous branches
Mostly, water flows only one way over the gills, which reduces amount of energy needed
Ventilation: oxygen-containing medium moving over respiratory surface
Fish
Some aquatic organisms use counter-current exchange mechanism
water enter mouth and passes over the gills
water and blood flow in opposite directions
oxygen diffuses from the water into the blood, along a concentration gradient
diffusion gradient of oxygen remains high
Tracheal respiratory system
Gas is exchanged through pores of tracheae, diffuses through it
Does not need circulatory system
Grasshoppers
Air enters tracheal tubes through spiracles
trachea carries air to individual cells → diffusion
contraction of abdominal muscles compresses air sacs + forces out air
Lung
3 common characteristics
moist respiratory surface
means of forcibly bringing air into contact with lung surface
circulatory system carries gases between lungs and other cells of body
Frog
Bird
fresh air posyerior sac
stale air anterior sac
Parts of respiratory system
Pharynx
the passageway just behind the mouth that connects the mouth and nasal cavity to the larynx and esophagus
Trachea
the tube that carries air from the nasal passages or mouth to the bronchi and then to the lungs; also known as the windpipe
Glottis
the opening of the trachea through which air enters the larynx
Larynx
the structure between the glottis and the trachea that contains the vocal cords
Bronchus
the passageway that branches from the trachea to the lungs
Bronchiole
the passageway that branches from each bronchus inside the lung into increasingly smaller, thin-walled tubes
Alveolus
a tiny sac, with a wall that is one cell thick, found at the end of a bronchiole; respiratory gases are exchanged in this sac
Epiglottis
a flap that covers over the glottis to prevent food from entering the trachea and passing into the lungs
Pleura
membrane (sac) that covers lungs, between pleura and lungs there is a lubricant fluid
applies pressure equally to all parts of lungs, allowing inhalation + exhalation |
Inhalation & Exhalation mechanics
⬆ volume of vessel — ⬇ air pressure
⬇ volume of vessel — ⬆ air pressure
air always flows from vessel with higher pressure into vessel with lower pressure
involuntary respiration (no conscious effort)
inspiratory center — located in medulla oblongata
Inhalation
diaphragm contracts + flattens
external intercostal muscles draw ribs upward + outward
increases thoracic volume, decreasing intrapulmonary pressure → since volume increases, air pressure decreases, so air enters lungs
Expiration
passive process
diaphragm + external intercostal muscles relax
decreases volume of thoracic cavity, increasing air pressure, so air is expelled from lungs
pressure in lungs exceeds atmospheric pressure
Forced Exhalation
internal intercostal muscles contract, depressing the rib cage
abdominal muscles contract, pushing organs in abdominal cavity against diaphragm
decreases thoracic volume, increases air pressure, air is expelled
Lung Volume Calculation
TV - Tidal Volume: volume of gas inspired or expired during each normal (unforced) ventilation cycle (volume of air moved into the lungs in a single breath)
ERV - Expiratory Reserve Volume: maximum volume of gas that can be forcefully exhaled after a normal exhalation
IRV - Inspiratory Reserve Volume: maximum volume of gas that can be forcefully inhaled after a normal inhalation
RV - Residual Volume: amount of gas left in lungs after a maximum (forced) exhalation (necessary otherwise lungs would collapse)
VC - Vital Capacity: maximum volume of gas that can be exhaled by voluntary effort after a maximum inhalation
TLC - Total Lung Capacity: amount of gas in lungs after a maximum (forced) inhalation
Calculations (chart given)
Gas exchange – where does it happen, why does it happen, how does it happen
Inhale — composition of gas
O2: ~21%, CO2: 0.04%, N2: 78%, Inert gas: 1%
Exhale — composition of gas
O2: ~16.5%, CO2: 4.5%, N2: 78%, Inert gas: 1%
Gas exchange is determined by 2 factors
Surface area of respiratory system
Difference of concentration of gases across membrane
Total air pressure of a mixture of gases = sum of partial pressures of its component gases
Partial pressures of gases affect gas exchange
Diffusion (of oxygen)
Gases will diffuse from area of high pressure to area of low pressure until equal
⬆ pressure gradient = ⬆ rate of diffusion
O2 diffuses to cells of capillaries, to blood plasma, then across cell membranes of RBC
In RBC, oxygen forms bond with hemoglobin
hemoglobin + O2 → oxyhemoglobin
99% of oxygen is transported through hemoglobin
RBC circulate rapidly in blood stream, transporting oxygen to all body cells
The PO2 in alveoli is less than PO2 of external surrounding air
Some residual/stale air remains in alveoli, reducing overall proportion of oxygen
Diffusion of oxygen still occurs from air in alveoli → blood because there is a pressure gradient (PO2 in blood is less than PO2 in alveoli)
Removal of carbon dioxide
Diffusion of cells to blood (~7% held in plasma)
Attaches to hemoglobin + carried by RBCs to lungs (~20%)
Combines with water to form bicarbonate (HCO3-) and hydrogen ions (H+) (73%)
H+ causes blood to become more acidic + can be fatal in high conc., therefore must be removed
H+ is taken by oxyhemoglobin, oxygen is released by oxyhemoglobin and used for cellular respiration (dissolved in blood fluids)
H+ react with HCO3-, releasing CO2 and H2O which are released by lungs
Respiratory Control
Homeostasis: maintenance of constant internal environment
Regulation of CO2 and O2 levels in body
Regulated by 2 systems
Nervous control: area in brain called respiratory/inspiratory center (medulla oblongata) has nerve fibres that connect it to muscles of rib cage + diaphragm
Chemical control: chemical receptors in walls of arteries detect changes in CO2, send signals to respiratory center
Carbon monoxide vs oxygen & hemoglobin
Factors affecting breathing rate
Internal:
increased levels of CO2 in blood
respiratory disease (common cold, influenza, TB)
amount of cellular activity (muscle cells require more energy when they are worked, gas exchange will increase)
Environmental:
higher altitudes — air is thinner with less O2, breathing rate increase
emotion
dust, pollen
smoke (carbon cannot be filtered)
industrial chemicals (carbon monoxide (CO), ammonia, methane cause inflammation)
Oxygen & hemoglobin
Diffusion (of oxygen)
Gases will diffuse from area of high pressure to area of low pressure until equal
⬆ pressure gradient = ⬆ rate of diffusion
O2 diffuses to cells of capillaries, to blood plasma, then across cell membranes of RBC
In RBC, oxygen forms bond with hemoglobin
hemoglobin + O2 → oxyhemoglobin
RBC circulate rapidly in blood stream, transporting oxygen to all body cells
Removal of carbon dioxide
Attaches to hemoglobin + carried by RBCs to lungs (~20%)
H+ is taken by oxyhemoglobin, oxygen is released by oxyhemoglobin and used for cellular respiration
Respiratory diseases/disorders
If patient has ___ diagnose them
Pneumonia (inflammation in lungs, alveoli, fill with fluids) - bacterial/viral infection
Definition
Inflammation in one or both lungs — alveoli
(When alveoli become inflamed and fill with fluids)
Interferes with gas exchange, as body becomes starved for oxygen
Lobular: affects a lobe
Bronchial: affects patches in both lungs around bronchi/bronchioles
Types, Causes, Diagnosis, Treatment
Bacterial Pneumonia
caused by bacterial infection
Lobular: Bacterium Streptococcus pneumoniae**:** can spread out of lungs through bloodstream, affect other tissues
Preventative vaccine: Pneumococcal vaccine provides long-term protection
Viral Pneumonia
caused by viral infection
Less severe than bacterial pneumonia
Treatment: anti-viral medication
However, can be followed by secondary bacterial infection
Treatment: antibiotics
Rare type of pneumonia
experienced by those with AIDS (have weak immune systems)
Bronchitis (inflammation of mucous membranes of bronchi, accumulate, coughing) - smoking
Definition
Inflammation of mucous membranes of bronchi
(When bronchi become red, inflamed, and filled with mucus which is expelled by coughing)
Types, Causes, Diagnosis, Treatment
Acute (short-term)
caused by bacterial infection
Treatment: antibiotics
Chronic (long-term)
caused by cigarette smoke or regular exposure to concentrations of dust/chemical compounds in workplace
take place over long period of time → cilia lining + bronchi are gradually destroyed
classified as COPD (Chronic Obstructive Pulmonary Disease)
Symptom: persistent cough
without cleansing of cilia, bronchi grow increasingly inflamed + vulnerable to infection
mucus accumulates in bronchi, attempt to clear it with cough
Treatment:
incurable, but managed
quit smoking, take medications, participate in exercise programs
Asthma (inflammation of bronchi/bronchioles, narrow air passage/airflow, overproduce mucus) - from irritants
Definition
inflammation of bronchi/bronchioles caused by inhaling irritants like pollen, dust, smoke
narrows air passage of bronchi/bronchioles, reducing airflow
overproduction of mucus
Causes
Irritants like pollen, dust, smoke
Symptoms
Wheezing, coughing, tightness in chest, shortness of breath
Asthma attack: muscles around airways contract, increased mucus production, which further blocks airflow
Treatment
incurable, but managed
hand-held inhaler, delivering medication deep into lungs
metered dose inhaler (pressurized canister with mouthpiece)
trigger the release and inhale liquid medication in a mist
dry powder inhaler
fine, powdered dose of medication through deep, slow inhalation
medications relax the bronchiole muscles + reduce inflammation, opening airways
can monitor lung capacity to give warning of reduced airflow
measure lung volume with peak flow meter: if lung volume is decreasing, there may be an asthma attack coming
Emphysema (alveoli walls break down, reduce respiratory surface, less oxygen, trap air) - smoking
Definition
walls of alveoli lose their elasticity
this reduces respiratory surface for gas exchange, causes oxygen shortage
exhaling becomes difficult: small airways collapse during exhalation, trapping air in lungs + blocking airflow
classified as COPD (chronic obstructive pulmonary disease)
Causes
smoking
Treatments
incurable, but managed
use inhaler to open up bronchioles
use low-flow oxygen tank to boost supply of oxygen in body
stop smoking + avoid airborne irritants like dust/second-hand smoke
Cystic Fibrosis (thick mucus buildup) - genetic mutation
Definition
genetic condition causes thick, sticky buildup of mucus that clogs the lungs
leads to difficulty breathing, infection, inflammation, damage to lung tissues
mucus traps disease-causing agents, making it difficult to clear bacteria that cause lung infections
mucus blocks ducts of pancreas, preventing digestive enzymes from reaching intestines to digest
Causes
Gene mutation
production of a slightly different protein, which is supposed to govern balance of salt + water
lack of normal protein causes extra thick, sticky mucus
Treatments
incurable, but managed
relieved by medicines that thin the mucus
antibiotics that reduce bacterial infections
gene therapy - life-saving treatment
treat patients with copy of normal gene
new methods tested: using capsules, sprays, and nose drops to deliver unmutated gene to cells lining the airways
tiny bubbles (liposomes) in the sprays/drops contain DNA without mutation
they diffuse with outer surface of the cells + the DNA passes through
it instructs cells to make the normal protein
Lung Cancer (carcinoma, metastasis) - carcinogens (tobacco)
Definition
uncontrolled cell growth + division in the lungs
creates a carcinoma — tumour made up of rapidly multiplying cells
can grow as large as 8cm, reducing respiratory surface of lungs
metastasis — cancerous cells break away from tumour + spread to other organs/parts
**leading cause of cancer deaths for men and women
Symptoms
difficult to detect early — lungs are deep in thoracic cavity
persistent cough, difficulty breathing, chest pain, loss of appetite
x-ray does not show presence of tumours until they are large + spreading
Causes
carcinogens — smoking tobacco
persistent exposure to second-hand smoke, radon (radioactive gas found in rocks/soils/buildings), asbestos (mineral used as insulation in buildings)
Treatments
Radiation therapy
X-rays/other types of radiation to destroy cancer cells
external therapy from high-dose radiation from machine
internal therapy through thin plastic tube in lungs
Chemotherapy
drugs destroy cancer cells + stop/slow growth
taken by mouth or injected into the body
used in more advanced stages of cancer
however, it can also harm healthy cells that divide quickly, like skin, mouth, digestive tract
side effects: loss of hair, nausea, mouth sores
Lung surgery
removing area of lung that contains tumours
can be small part of lung, lobe of lung, or entirel ung
if metastatic cells remain, the cancer may begin to spread again
Laser surgery
destroy lung tumours with a laser
minimal impact on surrounding tissues, minimize scarring/damage to lungs
the heat seals blood vessels + reduces blood loss/swelling, speed up healing
Diagnosis
Review Questions:
(Answers on unit review)
Pg 471: Q#1-13
c
d
e *
Some aquatic organisms use counter-current exchange mechanism
water enter mouth and passes over the gills
water and blood flow in opposite directions
oxygen diffuses from the water into the blood, along a concentration gradient
diffusion gradient of oxygen remains high
b
mechanics: air pressure is controlled by 2 muscular structures. Inhalation is result of contraction of diaphragm and external intercostal muscles.
e
c
e
b
pleura: 2 thin membranes covering lungs
Structure of mammalian lung: the surface of lung, vast alveoli, and blood vessels cover a large area for gas exchange, and it all occurs inside the body with mucus and blood, keeping it moist
Inhalation: diaphragm contracts and flattens, increasing the volume of the lung Exhalation: diaphragm relaxes, decreasing volume of thoracic cavity
emphysema (alveoli)
Inflammation of pleural membrane → breathing becomes difficult, as the inflammation prevents membranes from sliding past each other smoothly (lubricant fluid)
air is warmed and moistened to make gas exchange more efficient into capillaries
warmed? — prevent shocking blood with cold air
Pg 474-475: Q#1-15, 21-23
e
d
all terrestrial vertebrates (except amphibians) breathe by expanding their lungs, creating counter-current pressure within lungs
d
d
c
c
most oxygen is carried by blood bound to hemoglobin, most carbon dioxide is transported by blood dissolved in blood fluids
d
c
blood in capillaries have higher concentration of CO2 relative to alveoli because it is returning from body tissues.
a
b (internal respiration)
larynx, epiglottis, bronchiole, diaphragm
pharynx (throat) is a passageway for both air and food (respiratory and digestive systems), so the epiglottis a flap that prevents food from going into the respiratory system and damaging it. “The trachea is strengthened by semicircular, cartilaginous arches that prevent it from collapsing. Th e open part of the semicircle faces the esophagus and allows the esophagus to expand when food is being swallowed.”
Carbon monoxide is so toxic because your lungs cannot filter carbon (?). Since carbon monoxide easily binds to hemoglobin, it will block oxygen from being transported through the hemoglobin. Your body will be deprived of oxygen
oxygen is mainly transported by hemoglobin during gas exchange, and carbon dioxide is transported through a variety of methods, but mainly bicarbonate ions. Carbon dioxide can also be transported through blood plasma and hemoglobin.
examples
Bronchitis: airways are inflamed due to infection, chronic coughing in an attempt to release extra mucus
Emphysema: alveoli walls break down + lose their elasticity, less surface area for respiration/gas exchange, less oxygen, exhaling is also difficult
Asthma is a respiratory disease that causes airways to become narrower and reduces airflow. This is because the bronchi and bronchioles are inflamed due to irritants. It becomes very hard to breathe and there may be asthma attacks. It can be managed with medication.
venn diagram
Emphysema
similar
Asthma
caused by smoking
alveoli walls break down + lose their elasticity
less surface area for respiration/gas exchange
less oxygen
exhaling is difficult | chronic/incurable respiratory disease blockage in airways: harder to breathe/get oxygen can treat with inhaler, both open up bronchioles | caused by sensitivity to irritants from a young age
airways to become narrower and reduces airflow
bronchi and bronchioles are inflamed due to irritants.
very hard to breathe and there may be asthma attacks.
overproduction of mucus |
Diagnosis
chronic bronchitis: persistent cough that produces mucus, consistently exposed to irritants
There could be many other possibilities, there is still not enough information:
persistent coughing that produces mucus happens in many other diseases
many other diseases are caused by exposure to irritants (e.g. asthma, cystic fibrosis)
you could determine what is in the mucus, determine lung capacity (spirometry), determine if there is lung damage, conduct genetic tests for cystic fibrosis
trachea?
this procedure would send oxygen/air directly into the respiratory system, ignoring blockages in the pharynx, larynx, nasal passages, etc. and allowing patient to have oxygen
Digestive System
Lessons Covered
Function of Digestion — Nutrition
Human Digestive System - I
Human Digestive System - II
Digestive System Disorders
Nutrients
Eating
→ energy for
Growth
maintenance
renewal of body tissue
regulatory chemical reactions
Nutrients — Elements/compounds an organism needs but is unable to manufacture itself
macronutrients
Carbs
Fats
Proteins
(Nucleic acids - DNA, RNA)
micronutrients
Water
Vitamins + Minerals
Carbs — main source of energy
(contain carbon, oxygen, hydrogen atoms)
includes sugars, starches, glycogen, cellulose
Types
monosaccharides (single sugars) — glucose, fructose
disaccharides (double sugars) — sucrose, lactose
polysaccharides (long strands of sugar) — starch, glycogen, cellulose
Lipids/fats — energy, absorption, insulation
Functions
Source of energy (2x carbs)
absorbs some vitamins
insulation
cell membrane component
certain hormones
lipids = glycerol + fatty acids
Types
unsaturated — liquid at room temp
good fats (e.g. vegetable oil)
saturated — solid at room temp
bad fats (e.g. animals + butter)
Cholesterol — soft waxy lipid in body cells + among lipids in arteries and veins
Function — form cell membranes, insulate nerves, produce vitamin D, bile, acids, some hormones
Sources — meat, shellfish, whole-milk, egg yolks, produced in liver
Liver already produces as much cholesterol as the body needs
Extra gets converted to lipoproteins
LDL: low density lipoproteins (BAD) → causes plaque in arteries
HDL: high density lipoproteins (GOOD)
Proteins → made of amino acids, building blocks
Functions
During starvation (necessary, no more fat or glycogen), liver will break down amino acids to provide energy
Necessary for building cells, structure + organs, and regulatory functions (enzymes, hormones)
humans have 20 amino acids responsible for making all our body proteins
12 are non essential (body can make from other foods), 8 are essential (must be found in foods)
Water
chemical reactant
solvent (dissolves substances so they can cross membranes)
lubricant (protects cells from damage)
part of cytoplasm
transporter products from organelles
regulator of body temp.
Minerals — inorganic elements that body needs (small amt)
help chemical reactions, build bones + cartilage
does not contain carbon
readily absorbed into bloodstream
calcium
dairy, leafy greens
bone formation, muscle contraction, blood clot
iron
red meat, leafy greens, raisins
hemoglobin synthesis
potassium
fruits (esp. bananas), vegetables
nerve + muscle conduction
sodium
table salt, vegetables
nerve conductions, osmotic balance
Vitamins — organic compounds that body needs (small amt)
usually serve as coenzymes (chemicals needed to make enzymes function)
development of tissue
fight and resist diseases
Categories
Fat-soluble
Vitamin A, D, E, K
only vitamin A + D can be stored
Water-soluble
Vitamin B, C
sometimes removed when foods are cooked in water
Human digestion
Gastrointestinal (GI) tract or alimentary canal
open at both ends (mouth and anus)
long convoluted tube with accessory organs
Digestion terms
Ingestion — taking food in
Digestion — breaking food down (catabolism)
Absorption — taking nutrients in
Egestion — releasing waste
Enzymes
Proteins formed by secretory cells, then secreted into the digestive tract
Can’t work in high temp.
Often need presence of metallic ions, vitamins, coenzymes to function properly
most end with -ase
Substrate — a molecule that enzyme acts upon
Hormone
a chemical regulator that is secreted int one part of the body, and transported to another to cause a response
Digestive System Processes
Metabolism — total of all chemical reactions in body
catabolism + anabolism + other processes
Catabolism — breaking large molecules into small molecules
Anabolism — process of connecting small molecules to form large molecules
End result of Digestion
produce waste
produce useful nutrients to diffuse into cells
Steps in digestion
Ingestion
Digestion
Absorption
Elimination
Types of Digestion
Mechanical — physical breakdown of food
mouth, stomach, (SI)
Chemical — chemicals + enzymes break down food
mouth, stomach, SI
Parts of the digestive system and the functions of each part
Oral Cavity/Mouth
Mechanical digestion — lips, tongue, teeth, jaw break food down into smaller pieces
Chemical digestion — food mixes with salivary amylase, which begins chem digestion of carbs
the enzyme amylase chemically digests starch into sugar (glucose)
Bolus (moistened ball-like mass) forms + is swallowed
Structures
hard palate — front part of roof, made of bone + skin, used in breakdown of food
soft palate — back part of roof, made of muscle, expands for swallowing
uvula — pinkish-red pointed structure hanging from soft palate, directs food down esophagus
Salivary glands
parotid glands — secrete a watery fluid that contains salivary amylase, lie just below skin in front of each ear
sublingual glands — below tongue in floor of mouth, produce saliva
submandibular glands — below roof of tongue in throat, produce saliva
Swallowing
leaving mouth — bolus must cross respiratory tract (trachea is anterior to esophagus)
Swallowing — empties the mouth + ensures that food does not enter trachea (windpipe)
coordinated activity of tongue, soft palate, pharynx, esophagus
voluntary — food forced into pharynx by the tongue
involuntary / reflex — tongue blocks mouth, soft palate closes off nose, larynx rises so epiglottis closes off trachea
food moves into pharynx and onwards by peristalsis + gravity
if we try to talk while swallowing, food may enter respiratory passages, cough reflex to try to expel the bolus
Esophagus
muscular tube that connects pharynx + stomach
bolus passes through pharynx, past epiglottis, + through esophagus
constriction of this ring of smooth muscle prevents reflux (ensures one-way flow of food)
peristalsis — series of coordinated muscular contractions that propel food along the digestive tract into the stomach
Stomach
J-shaped stretchable organ
Functions: reservoir for food + main digestion
2 sphincters control movement of food coming into + out of stomach
Cardiac sphincter/LES (lower esophageal sphincter) — between esophagus + stomach
pressure exerted by food on sphincter causes it to open, food enters stomach
Pyloric sphincter — between stomach + SI
Smooth muscle forms folds (rugae) that allow stomach to expand
Mech digestion — walls churn + squeeze bolus (peristaltic)
Chem digestion — bolus mixes w/ gastric juices
bolus becomes chyme (liquefied paste)
Specialized cells
Mucous secreting cells —lubricate stomach’s wall + protects stomach lining with mucus (contains bicarbonate - basic)
Parietal cells — secret hydrochloric acid
Chief cells — secrete pepsinogen
Small intestine
Sections
Duodenum
Jejunum
Ileum
Villi — lined with tiny finger-like projections, project into lumen (hollow interior)
Microvilli line the villi
Function — increase surface area for absorption (villi: 10x, microvilli: 500x)
Functions
break down carbs, proteins, fats by their respective enzymes (Chem digestion)
absorption of monosaccharides (sugars), amino acids, fatty acids, + glycerol by microvilli
through active transport + diffusion
Mech digestion: alternating contraction + relaxation of smooth muscle mixes chyme with intestinal juices + secretions from pancreas + liver
Nutrients absorbed into capillaries in villi
Nutrients transported to liver, then all body cells
Products from fat digestion are absorbed into lacteals (small lymph vessels) which connect to lymphatic system
Pancreas
Function: specialized for secreting hormones/enzymes necessary for proper digestion
Finger shaped organ below stomach
Contains a duct that empties into small intestine
acidity of chyme triggers cells in duodenum to release hormone called secretin
secretin enters bloodstream, signaling release of bicarbonate ions (base) from pancreas
bicarbonate ions neutralize HCl in duodenum, raising pH so that pepsin becomes inactive + allows digestion of nutrients
Pancreatic enzymes
lipase — digest lipids
carbohydrase / pancreatic amylase — digest sugar + starches
protease — digest proteins
trypsinogen — released + activated (to become trypsin) in SI to digest proteins
also produces hormone insulin (regulate blood glucose levels, allows glucose to enter body cells)
Liver
Functions
regulate metabolism
produce + secrete bile into SI
remove any toxins (e.g. hydrogen peroxide, alcohol, drugs) via catalase
Blood from stomach + SI are directed to liver
when glucose levels are high — glucose converted to glycogen
when glucose levels are low — liver breaks down glycogen
Synthesizes + secretes bile
bile emulsifies fat (break down big blobs of fat into smaller blobs, help digestion, e.g. dish soap)
Has left + right lobe
Gallbladder
Function — stores + concentrates bile
under liver’s right lobe
When fat enters duodenum, CCK (cholecystokinin) is released, signaling gallbladder to release bile through bile duct + into duodenum
Large intestine (larger diameter, but shorter length than SI)
Functions
Absorbs water, salt, some vitamins (NO DIGESTION)
holds + compacts unabsorbed material (cellulose - a dietary fibre / bacterial fragments)
Sections
Cecum
Colon
Rectum
Anus
process
Chyme passes from SI to cecum through ileocecal valve (ileum → cecum)
waste products accumulate + compacted into feces (3/4 water, 1/4 solid matter)
feces pass through rectum + exit body through anus
appendix — attached to cecum, function is unknown
Sphincters (controlling defecation)
Rectal sphincter — between LI + rectum
Anal sphincter — between rectum + anus
Digestive system parts diagram
Table of digestive enzymes
Location
Enzyme
Substrate
Digestion End Products
Salivary Glands
Amylase
Starch
Glycogen
disaccharides (double sugars)
Stomach
Pepsin
(activated from low pH)
Polypeptides (big protein)
Short peptides (small protein)
Small intestine
Peptidase
peptides
amino acids (digests proteins)
nuclease
DNA, RNA
nitrogen bases + sugar
lactase, maltase, sucrase
disaccharide
(double sugars)
(lactose/maltose/sucrose)
monosaccharides
(simple sugar)
Pancreas
lipase (goes in SI)
triglyceride (fats)
fatty acids & glycerol
trypsin (goes in SI)
short peptides
peptides
Table of digestive hormones
Hormone
Source
Stimulus
Action
Gastrin
Pylorus of the stomach
Entry of food in stomach
Stimulates secretion of HCl
Cholecystokinin (CCK)
Duodenum (SI)
Arrival of chyme in SI
Stimulates release of bile from gallbladder
Stimulates secretion of digestive enzymes from pancreas
Secretin
Duodenum (SI)
HCl present in duodenum
Stimulates secretion of bicarbonate ions from pancreas
Digestive System Disorders
Peptic Ulcer — mucous lining is weakened/prevented, stomach walls are damaged
Definition
sore in the lining of the stomach/duodenum, where hydrochloric acid and pepsin are present
most commonly caused by infection with bacterium helicobacter pylori
Ulcer forming
Ulcer — form when tissues become inflamed because the protective mucus that covers the lining has weakened
Most ulcers begin when populations of acid-resistant bacterium (helicobacter pylori) attach themselves to wall of digestive tract and prevent that area from producing protective mucus
Causes
obesity, alcohol, smoking
Symptoms
Abdominal pain, bloating, nausea, and loss of appetite
Very painful — exposed, unprotected tissues comes into contact with acidic gastric juice
Treatments
Antibiotics — caused by a bacterium
antacids — to neutralize acids?
Lifestyle — lose weight, avoid alcohol, don’t smoke
Inflammatory Bowel Disease (IBD) — chronic, crohn’s or ulcerative colitis
Definition
name for diseases that cause inflammation in intestines
increasing in children + western countries
IBD Treatment
chronic — cannot be cured, only treated
special diet
medication to reduce pain/inflammation
Types, Causes, Diagnosis, Treatment
Crohn’s Disease
IBD that can affect any part of alimentary canal (mouth → anus)
children do not grow properly during puberty
develop thinner bones that increase future risk of fractures
poor muscle development
Ulcerative Colitis
IBD (ulcer) that attacks the colon
Symptoms
loose/bloody stools (poo)
cramps, abdominal pain
Treatment
severe cases — surgeons remove affected part of the colon and create a new external opening for digestive waste
Constipation — dry, small, difficult stools, little water
Definition
bowel movements are reduced to 3/week or less
stools are dry, small, difficult to eliminate
Causes
inadequate water intake, leaving stools
lack of good nerve/muscle function in the bowel
unhealthy diet, lack of physical activity
Treatments
drinking more water
ingesting fibre
in fruits, vegetables, grains
e.g. whole grain bread, brown rice, whole grain pasta, beans, peas, lentils, seeds like flax, some fruits/vegetables
not a nutrient, not digested — passes through body almost unchanged, made up of cellulose
the bulk + soft texture of fibre helps prevent constipation
Hepatitis — inflammation of liver, life-threatening, A B C, vaccines
Definition
inflammation of liver, most commonly caused by virus
life-threatening
Hepatitis A
Cause — drinking contaminated water
Hepatitis B
Cause — spread by sexual contact
Treatment — vaccine to protect against it
Hepatitis C
Cause — contact with infected blood
No vaccine for this
Cirrhosis — chronic, replacement of liver tissue with scar tissue
Definition
irreversible replacement of healthy liver tissue with non-functioning scar tissue
occurs when scar tissue replaces healthy liver tissue and prevents liver from functioning properly
chronic
Causes
chronic + excessive alcoholism
hepatitis C
Symptoms: blood test — determine if liver is becoming fatty
Treatment: liver transplant
Gallstones — small hard masses from bile (crystals), blockage in ducts
Definition
small hard masses that form in the gall bladder
gall bladder stores bile from liver — cholesterol in the bile can precipitate out and form crystals
they grow and become gallstones
Causes
obesity, alcoholism, heredity
Treatments
medications
ultrasound shock waves disintegrate the stones so they can be passed out in urine
they will reoccur — reduce causal factors
losing weight to reduce cholesterol + decrease size of meals
taking omega-3 fatty acids (unsaturated fats in fish/nut oils)
Severe cases — entire gall bladder is removed
Diabetes — chronic, can’t use glucose for energy, insulin problem, type 1 2 gestational
Definition
chronic disease where body cells can’t use glucose for energy (for muscles + tissues)
diabetes develops when there is not enough insulin in bloodstream or body cannot properly use insulin that pancreas makes
without insulin, glucose cannot get into cells, and blood glucose level increases to life-threatening levels
Background knowledge
Normally, pancreas releases insulin into bloodstream after eating — insulin allows glucose from digested food to enter body’s cells, lowering amount of glucose circulating in bloodstream
as glucose in bloodstream drops, so does the release of insulin from pancreas
glycogen can be temporarily stored in liver so that when insulin gets too low (like not eating for a while) some of the glycogen is converted back to glucose to keep blood glucose at normal level
3 Types
Type 1
Occurs when insulin-producing cells of pancreas are destroyed by immune system, no longer produce insulin
most common in children, teens, young adults
Type 2
Occurs when body doesn’t make enough insulin / is unable to properly use insulin
most common in age 40+, but increasing for children
Gestational diabetes
Develops during pregnancy — often ends when baby is boring
more likely to develop Type 2 later in life
Causes: pregnancy hormones, inadequate levels of insulin production
Treatments
insulin injections — saved millions of lives
Developed + manufactured human insulin
genetically engineered bacteria (plasmids)
timing insulin delivery
computerized insulin pumps that monitor blood glucose levels
provides better control over blood glucose levels, reducing long-term complications
very expensive compared to insulin injection syringes
must be attached to body most of the time
Causes / Risk factors
advanced age, family history/hereditary, high-risk ethnic groups (aboriginal, african, asian, hispanic, pacific island)
Diagnosis — endoscopy
Non-invasive surgery
don’t need to cut in to body
painless + fast recovery
complications are rare
can be carried out with only a local anesthetic
reduces risk of infection
Endoscopy
helps confirm medical problems that are hard to observe using other methods (like X rays)
visually inspect lining of any part of the alimentary canal, including stomach
tube through alimentary canal, can have light, camera for pictures, laser to cut through tissue, tiny forceps to extract tissue for examination
Capsule endoscope
tiny camera placed inside a capsule that can be swallowed
especially useful for seeing inside of small intestine, which is too long for endoscope tube to be pushed through
Animals — feeders?
filter feeders
aquatic animals that use body structure similar to a filter basket to gather organisms
siphons water into mouth and filters to obtain small organisms to digest
e.g. tube sponge, flamingo, tube worm, clam, barnacle, baleen whale
substrate feeders
live in/on their food source and eat their way through it
e.g. caterpillars, earthworms
fluid feeders
sucking/licking nutrient rich fluids from live plants/animals
have mouth parts that pierce/rip skin or leaf tissue, + suck blood/sap
e..g mosquito, bee, hummingbird, butterfly
bulk feeders
ingest large pieces of food
swallow it whole, or use tentacles, pincers, claws, fangs, jaws, teeth
many animals, most vertebrates (humans), blue heron
Review concepts mentioned
The specialized cells of the stomach
Mucous secreting cells —lubricate stomach’s wall + protects stomach lining with mucus (contains bicarbonate - basic)
Parietal cells — secret hydrochloric acid
Chief cells — secrete pepsinogen
Mechanical digestion and chemical digestion – what happens? Where does it occur?
Mechanical — physical breakdown of food
mouth, stomach, (SI)
mouth — chewing
Stomach Mech digestion — walls churn + squeeze bolus (peristaltic)
SI Mech digestion: alternating contraction + relaxation of smooth muscle mixes chyme with intestinal juices + secretions from pancreas + liver
Chemical — chemicals + enzymes break down food
mouth, stomach, SI
Mouth Chemical digestion — food mixes with salivary amylase, which begins chem digestion of carbs
the enzyme amylase chemically digests starch into sugar (glucose)
Stomach Chem digestion — bolus mixes w/ gastric juices (+ enzymes, pepsin)
bolus becomes chyme (liquefied paste)
SI Chem digestion — break down carbs, proteins, fats by their respective enzymes (many enzymes, connected to pancreatic duct)
Sphincters
2 sphincters control movement of food coming into + out of stomach
Cardiac sphincter/LES (lower esophageal sphincter) — between esophagus + stomach
pressure exerted by food on sphincter causes it to open, food enters stomach
Pyloric sphincter — between stomach + SI
ileocecal valve — si li
Sphincters (controlling defecation)
Rectal sphincter — between LI + rectum
Anal sphincter — between rectum + anus
Water-soluble vs Fat-soluble vitamins
Fat-soluble
Vitamin A, D, E, K
only vitamin A + D can be stored
Water-soluble
Vitamin B, C
sometimes removed when foods are cooked in water
Review questions
Pg 435: Q#1-16
d absorption
a carbs
d glucose
c epiglottis prevents food from entering trachea
b stomach
c LI does not produce bile
a ingestion → digestion → absorption → elimination
a filter feeders
bolus — after oral cavity, moistened ball lump of food chyme — after stomach, liquid paste feces — waste product, mostly water, 1/4 solid mass Chyme enables nutrients to be absorbed during digestion. It is a liquified paste that passes through the small intestine, allowing nutrients to be absorbed
t/f
false — minimize fat intake instead of protein, as gallbladder stores bile, and bile is important for fat digestion
true — herbivores need a larger cecum so they can store and process plant material/fibres
false — a substance that decreases water reabsorption in LI can lead to constipation
textbook wrong? if more water is absorbed from chyme/feces, it means the feces will have less water, leading to constipation
the mucous lining on the stomach’s wall prevents acid from damaging the stomach. this is because the mucous lining contains bicarbonate, which is a base and neutralizes stomach acid.
also gastric juices are only secreted when food is present
also pepsin is secreted in an inactive form until HCl is present
chewing food is mechanical digestion, breaking down the food so that it becomes a bolus and is easier to digest. it also gives time for the salivary amylase to chemically digest starch into glucose
the esophagus connects the mouth to the stomach. pharynx is in between mouth and esophagus, and the LES is in between esophagus and stomach. the bolus goes down the esophagus through gravity and peristalsis, which are involuntary movements and contractions.
also glands in esophagus produce mucus, keeps it moist + aids swallowing
liver — produces bile, which is important in digesting fats, as it emulsifies them. the bile gets stored in the gallbladder and is released in SI. lipids are important for energy and liver helps digest them
t/f
true
false — undigestible food matter passes through colon, food matter is all digested, nutrients absorbed before it enters the colon
true
true
true
gallstones will cause problems if not removed, as they can damage surrounding organs. this is because they will clog up the gallbladder, blocking bile from being released in the bile ducts between the liver and SI.
Pg 438 – 439: Q# 1-11, 15-23
b butterfly
c digestion
a protein
d mouth, pancreas, SI have enzymes that break down carbs
c lipids = glycerol and fatty acids
d trypsin in small intestine
a pancreas, starch digestion
b lipids and carbs for energy
d chewing food in mouth
a starch storing energy in plants
protein functions — building blocks: important for building cells, tissues, muscles, and repairing them
if there is no fat or glycogen and it is necessary, amino acids will also be broken down for energy
(regulatory functions, as enzymes/hormones)
gastrointestinal tract: mouth/oral cavity → esophagus → stomach → small intestine → large intestine → out through anus accessory organs: pancreas under stomach, liver above stomach, gallbladder under liver
this is because of peristalsis — involuntary muscle contractions
ulcers are sores/inflammation in tissue. a peptic ulcer is in the lining of the stomach/duodenum, and it is most likely caused by a specific bacterium that stops the wall from producing mucous. this means the stomach acid will not be neutralized in that area and will damage the wall.
diabetes
type 1: body no longer produces insulin because immune system destroys the insulin-producing cells
type 2: body does not produce enough insulin or cannot use the insulin it produces
this patient is likely to be diagnosed with ulcerative colitis, as bloody stools, cramps, and abdominal pain are all symptoms. ulcerative colitis is an IBD that affects the colon. as the colon is damage, it changes how chyme is processed into feces, and how water and salt is absorbed.
graph
title: activation of pepsin based on pH level *(”Enzyme Reaction by pH”)
pepsin
stomach
when pH levels are low in the stomach, this means HCl is being released, and it is only released when there is food. therefore, this enzyme is only activated when the stomach is digesting food
pH affects all enzymes
the stomach does not digest its own lining because the lining in the wall has mucous, which has bicarbonate that neutralizes acids. it protects the stomach from digesting itself and other organs.
also, HCl is only released when food is present, and pepsin/digestive enzymes are only released when there is acid.
crohn’s disease is an IBD that can affect anywhere in the GI tract. it is an inflammation in intestines/other organs. inflammations in the GI tract cause poor muscle/bone development because it negatively affects the organs’ ability to digest food and absorb necessary nutrients for growth.
it is dangerous to take more fat-soluble vitamins because they are stored in fat. unlike water-soluble vitamins, they are not released or dissolved in water. they stay in the fatty parts of body and may be dangerous or toxic.
Circulatory System
Blood — main transport medium, 3 solid types (RBC, WBC, platelets)
is a tissue — collection of cells that have been specialized to perform a set of particular tasks within an organism
2 parts
Plasma (fluid portion) — 55%
water, proteins, etc.
Solids (cellular component) — 45%
Red blood cells
carry oxygen, contain hemoglobin
White blood cells
attack bacteria + invaders
Platelets
control blood clotting
RBC (Erythrocytes)
manufactured in bone marrow, stored in spleen
lack a nucleus at maturity (no mitosis)
Shape: biconcave disc (donut, but hole doesn’t pass through)
replaced continually → around 3-4 months
Hemoglobin: RBC cytoplasm contains
protein-based molecule with 4 protein chains
each chain has an iron atom at its core
iron makes blood bright red
Hemoglobin bonding
oxygen forms a “loose” bond with 4 sites on hemoglobin
carbon monoxide forms a “stronger” bond to hemoglobin
Oxygenated blood — oxygen diffuses in + binds to hemoglobin molecule (bright red)
Deoxygenated blood — oxygen is released from hemoglobin + diffuses into tissues (dark red)
Factors of oxygen pickup + release
concentration of O2
when partial pressure is low, bond connecting oxygen to hemoglobin weakens, & O2 is released
acidity
more CO2 = acidity (forms carbonic acid with water)
increased acidity in blood weakens oxygen-hemoglobin bond, & O2 is released
temperature
cooler temperatures — hemoglobin releases O2 slower
determines activity level of cold blooded animals
of RBC
the less O2 the blood carries, the more RBC the bone marrow will make
severe bleeding/living at high altitude — increased RBC production
WBC (Leucocytes)
manufactured in bone marrow
larger than RBC
have nucleus at maturity (mitosis), amoeboid shaped (blob)
Antigens → foreign material in body
Antibody → protein that recognizes specific antigens, locks onto them and marks/flags it for destruction
Infection — WBC will produce antibodies + increase # of WBC
Types of WBC
Neutrophils
respond to tissue destruction by bacteria
provide a first line of defence for body
engulf microorganisms, cell debris, dying, dead cells by phagocytosis
Eosinophils
responsible for inflammatory + allergic response
engulfs parasites + antigen-antibody complexes
Basophils
intensifies allergic response
secrete anti-coagulant + antibodies
attacks parasites
Monocytes/macrophages
largest WBC
phagocytic (removes/engulfs foreign particles + germs)
Lymphocytes
produce antibodies that kill bacteria + toxins
latch onto foreign particles to mark them for destruction (phagocytosis)
Immune Response Terms
Innate immune response — macrophages engulf foreign pathogens (generalized response)
Acquired immune response — lymphocytes fight specific pathogens, lymphocytes are either T cells or B cells, there are diff types of T and B cells
pathogen — bacteria/virus/harmful microorganism
Steps to immune response
Immediate response
macrophages release histamine which dilates blood cells (makes area swollen + hot)
macrophages engulf invade (creates pus — sacrifices life)
protein antigens are pushed out of macrophage to help immune system identify it + use as a flag
1-2 days
lymphocytes react to flag → helper T cells communicate the structure + nature of the invader to KILLER T cells + B cells
killer T cells hunt invader + destroy all cells with the antigen (identified by helper T cells)
7-10 days (completion)
B cells produce plasma B cells, which start production of antibodies that disable the invader
invading cells agglutinate (clump) and are engulfed by macrophages
After immune response
immunity — memory B cells store the “recipe” for antibodies required
Platelets
granular, lack nucleus, form of oval discs
fragments of cytoplasm
2 parts
clear outer ground substance occupying greater part of platelet
central part that contains granules
Steps to blood clotting
tissue or blood vessel is damaged
platelets form a plug at opening/wound
ruptured platelets + damaged tissue cells release enzyme (prothrombin activator)
the enzyme + calcium ions convert inactive plasma protein prothrombin → its active form, thrombin in the plasma
thrombin converts fibrinogen (soluble inactive plasma protein) → fibrin (insoluble)
fibrin nets catch RBC + clot forms
Blood transfusion — types, Rh factor
Blood transfusion
if transfused with the wrong blood type, body starts making []-type antibodies to attack the []-type antigens
leads to agglutination (clumping of blood) + fatal consequences
Type O — universal donor, Type AB — universal recipient
DONOR
Blood type
O
A
B
AB
O
✅
RECEIVER
A
✅
✅
B
✅
✅
AB
✅
✅
✅
✅
Rh (Rhesus) factor
protein marker on RBC
person who is Rh+ has the protein, Rh- doesn’t
Rh- mother with an Rh+ child will make antibodies against Rh factor during birth
if next child is Rh+, danger
Blood Vessels — arteries, veins, capillaries
Arteries
Three structural layers
Outer layer: connective tissue
Middle layer: smooth muscle (thickest)
Inner layer: endothelium (smooth epithelial cells) → reduces friction
elastic, thick, muscular
can handle high pressure of pumped blood from heart
blood travels through arteries + stretches the wall
when artery relaxes, stored energy pushes the blood farther along
oxygenated blood (except pulmonary artery) away from heart
branch off to smaller, less elastic arterioles
Capillary bed
Capillary
thin, narrow diameter — one cell thick
abundant in whole organism
site of gas exchange with tissue cell (respiratory system — diffusion)
where RBCs pass through (single file)
Blood flow
moves slowly because there are more capillaries than arterioles
allows time for substances to be exchanged between blood + tissues
Veins
thinner wall (large inner circumference), greater diameter + blood capacity
lack elasticity (middle layer is thinner)
blood pressure is lower in veins
merge into smaller veins called venules
deoxygenated blood (except for pulmonary vein) towards heart
Blood flow
dependent on
skeletal muscle contraction
presence of valves in veins
respiratory movements
compression of veins causes blood to move forward past a valve — which prevents it from returning backward
Venous system
70% of total blood volume
most work against gravity
Valves — one-way flow of blood
contraction of skeletal muscles pushes blood toward heart
if constantly stretched, they will lose their elasticity + varicose veins will form (ew)
Temperature regulation
arteries + veins — blood flows in opposite directions
countercurrent flow — allows heat to be exchanged more efficiently
to preserve heat — surface blood vessels constrict + blood flow is reduced where heat might leave
vasoconstriction — constriction of blood vessels
vasodilation — dilation of blood vessels (become wider + open)
Blood pressure + heart rate
Blood pressure
measure of force of blood against arterial walls
Systolic pressure — when heart contracts
Diastolic pressure — when heart relaxes + blood fills heart
risks
normal blood pressure: 120/80 (Systolic/Diastolic)
pressure goes up when O2 is in demand (heart rate goes up)
artificial stimulants — caffeine, alcohol (temporary increase)
factors that affect BP
heredity, age
lack of exercise
smoking, obesity
Heart rate
men avg — 70bpm, women avg — 75 bpm
children + smaller people have higher average
athletes have a lower resting pulse
Heart rate change
temperature — high body temperate → increase heart rate
acidity — CO2 in blood (turn to carbonic acid) → increase heart rate
hormones — adrenaline, thyroxin, insulin, sex hormones affect heart rate
Lymphatic System
Functions
carries interstitial fluid + makes lymphocytes
helps maintain water balance in interstitial fluid
Terms
Interstitial fluid — fluid that constantly bathes all cells of body
Homeostasis — maintenance of internal environment at steady state, regardless of external changes
Lymph nodes
glands found in lymphatic system
produce lymphocytes + contain macrophages
will swell when sick (increased lymphocytes + macrophages)
steady-state relationship between: lymphatic system, interstitial fluid, circulatory system
fluid escapes from capillaries → form part of interstitial fluid
some fluid collected in lymph vessels → eventually return to blood
fluid in lymphatic system moves similarly to fluid in veins — valves + surrounding muscle contractions
Heart
HEART
made of cardiac muscle, has pacemaker
protected by fluid filled membrane called pericardium (reduces friction), ribs, sternum, spine
Heart tissue
Endocardium — lines the inside chambers of heart, smooth (reduce friction)
Myocardium — muscle tissue, enables necessary force for contraction
Anatomy
R & L Atrium — receives blood from veins
thin walls + do not generate much force — only push blood to ventricle
R & L Ventricle — delivers blood to arteries
thicker, muscular walls — push blood out through vessels + capillary beds in pulmonary/systemic circulatory systems
left ventricle has thickest walls — must force blood the greatest distance
Valves — open + close to regulate movement of blood
tricuspid (right A-V valve), bicuspid (left A-V valve, aka mitral valve)
pulmonary + aortic semilunar valves
3 Heart circuits + pathway
Pulmonary circuit
low pressure system
Deoxygenated blood from cells of body go to heart, to be pumped to lungs
Oxygenated blood from the lungs go to the heart, to be pumped to the rest of the body
BLOOD FLOW:
S&I VC → right side of heart → pulmonary arteries → lung → pulmonary veins → left side of heart → aorta → body
Systemic circuit
high pressure system
Oxygenated blood pumped to cells
Deoxygenated blood carried away from cells
blood leaves left side of heart to rest of body through aorta (largest artery)
Coronary circuit
L & R coronary arteries deliver oxygenated blood + nutrients to heart muscles
first vessels to branch off aorta
left coronary artery has 2 major branches
left circumflex artery
left anterior descending artery
Heart attack — blockage of coronary artery
Cardiac cycle (diastole + systole)
Cardiac cycle
cycle of relaxation + contraction
pacemaker (sinoatrial node/S-A node) maintains heart’s rhythmic pumping
Diastole
Systole
Relaxation phase
0.1s
Contraction of ventricles
has low blood pressure (diastolic pressure)
increased blood pressure (systolic pressure)
blood flows to all 4 chambers
blood flows out of ventricles
tricuspid + bicuspid valves are open
tricuspid + bicuspid vales are closed
lasts 0.4 seconds
lasts 0.3 seconds
Heart rate regulation + electrical pathway of the heart (nodes, signals)
regulating heart rate
medulla oblongata regulates heart rate
2 pairs of nerves run from medulla to pacemaker region
stimulatory nerve fibres in spinal cord (speed up heart rate)
inhibitory nerve fibres in vagus nerve (slow down heart rate)
Sinoatrial (SA) node determines the pace the heart beats
located in right atrium, aka pacemaker
Contraction
SA node is stimulated + sends electrical impulses through nerves of right atrium
signals are received by nerves between right atrium + ventricle: Atrioventricular (AV) node
AV node sends this signal to nerve fibres through septum called bundle of His
bundle of His branch out into smaller fibres that cover 2 ventricles (Purkinje fibres)
signals moving through Purkinje fibres cause ventricles to contract
Stroke volume, (heart rate,) cardiac output (also: calculation)
Cardiac output = amount of blood pumped by heart
factors
Heart rate
Stroke Volume (amount of blood forced out with each heartbeat)
FORMULA: cardiac output = heart rate * stroke volume
Stroke volume factors
stretchiness of ventricles (how easily heart fills with blood)
strength of ventricular contraction + pressure exerted by artery walls (how readily the heart empties again)
Regular cardiovascular exercise will increase the resting stroke volume of your heart
enlarges ventricular chambers, increasing stretchiness + strengthening ventricular walls
“Lub-dub”
Heart beat sound
LUB
heart’s systolic period (contraction)
tricuspid + bicuspid valves shut
semilunar valves open
DUB
heart’s diastolic period (relaxation)
tricuspid + bicuspid valves open
semilunar valves close
ECG (electrocardiograph) + PQRST Graph
detects heart’s electrical activity, electrodes attached to skin read ECG
P wave → contraction of atria
QRS complex → contraction of ventricles
T wave → relaxation of ventricles
Biochemistry of heart (from increased muscle activity + heart rate)
Increased muscle activity
more CO2 in blood → carbonic acid in blood
activates chemical receptors → medulla oblongata → releases noradrenaline (hormone)
S-A fires rapidly
heart beats faster
Increased heart rate
increased blood pressure
activates receptors in blood vessels → medulla oblongata → releases acetylcholine
S-A slows down firing
heart beats slower
How is heart rate and breathing rate connected?
Circulatory System Disorders
Anemia — less hemoglobin → less oxygen
Definition
decrease amt of hemoglobin
due to too few RBC, or reduced amt of hemoglobin in RBC
result — decrease of oxygen in system
Treatment — to offset side effects of fatigue, increase iron + vitamin B12 intake
Hypertension (condition) — increased blood pressure
chronically elevated blood pressure (high diastolic — health risk)
cause: increased volume/rate of blood or reduced elasticity of arteries
diet high in salt — increase blood volume
diet high in cholesterol — decreased elasticity (arteriosclerosis)
aging — increase blood pressure
obesity, smoking, lack of exercise
temporary increases — caffeine, nicotine, alcohol imitate effects of noradrenaline + increase heart rate
Effects:
blood clot formation
stroke — when blood clot or chunk of cholesterol travels to brain + decreases blood flow/blocks vessels in brain
heart attack — clot decreases blood flow to heart
Treatments
aspirin/any blood ‘thinners,’ which reduce clotting
angioplasty — balloon is inserted into closed artery, inflated, removed
coronary bypass — a block in a coronary artery is circumvented by another artery transplanted from leg (double = 2 arteries, triple = 3 arteries…)
surgeon grafts segments of another vessel (usually vein from leg), between the aorta + coronary vessels, bypassing areas of blockage
often 2-5 bypasses in a single operation
sphygmomanometer — inflatable cuff that temporarily stops blood flow through brachial artery
slowly releases it back + sounds of blood flow are listened to (with stethoscope)
Atherosclerosis (plaque in arteries, less elasticity, blockage/narrow)
Arteriosclerosis Definition
General term — several conditions where walls of arteries thicken + lose elasticity, becoming harder
Atherosclerosis — most common type
plaque builds up in artery walls
as artery narrows, blood flow is decreased + blood pressure increased
especially dangerous for coronary arteries, brain, legs, kidneys
Symptoms
chest pain, blood clots, shortness of breath, heart attack, heart failure
more than 90% of heart attacks are from atherosclerosis
Reducing risk
lifestyle — exercise, no smoking, low saturated fat diet, fruits + veg
Treatments
aspirin/medications
angioplasty — balloon to open artery, insert stent
coronary bypass — taking artery/vein from leg and creating pathway as replacement for coronary arteries
Aneurysm — bulge in artery that can burst (weakened wall)
definition
bulge in artery/heart chamber caused by weakened area of heart muscle/artery wall
blood pressure causes aneurysm to keep growing larger — risk of bursting
internal bleeding — death
mostly in aorta
causes
medical problems, genetic conditions, injuries → weakened/injured artery wall
treatment
surgery — removes damaged portion of blood vessel, replaces with graft/patch
Arrhythmia — irregular heartbeat speed/rhythm
Definition
problem with speed or rhythm of heartbeat
can lead to insufficient blood flow to brain/organs
Treatment
artificial pacemaker — emits electrical impulses to control rate
Stroke — arteries supplying brain damaged (Ischemic / Hemorrhagic)
Definition
arteries supplying blood to brain are damaged — cut flow of oxygen/nutrients to brain tissue
strokes kill brain cells in affected area
the longer the brain goes without oxygen, the greater risk of permanent brain damage
partial paralysis → death (nerve control to vital organs is affecte
Types
Ischemic stroke
when a clot in blood vessel blocks blood flow to brain
Hemorrhagic stroke
when a blood vessel in brain bursts + blood flows to surrounding brain tissue
Treatments
must be within few hours of symptoms
3 emergency treatments: clot busters (drug), surgery, non-surgical procedures
depends on stroke + time + person
Hemophilia — platelet clotting deficiency
inherited clotting disorder due to deficiency in a clotting factor
bumps + falls cause bleeding in joints, cartilage degeneration + reabsorption of bone can follow
most frequent cause of death is bleeding into brain with neurological damage
Symptoms — excessive blood loss if injured
Rationale — missing a protein for blood clotting
Treatment — blood transfusion
Leukemia — cancer of WBC (Myeloid / Lymphoid)
Types
myeloid
too many leukocytes — immature and unable to fight infection, crowd out RBC, causing anemia
lymphoid
cancer of lymphocytes — similar symptoms
acute — quick appearance, quick death
chronic — undetected for months/years
Symptom — an increase of WBC, but no infection
Treatments
blood transfusions, chemotherapy
Diagnoses
coronary angiography — mapping coronary arteries with dye + X rays
echocardiogram (ECHO) — ultrasound technology for pic of heart
exercise ECG — measures heart rate, blood pressure, etc. while exercising
holter monitor — records heart rhythm in daily life
event monitor — wrist
cardiac catheterization — thin, flexible tube (catheter) is inserted through artery, (through arm or groin), gently guided through body until heart, then use X rays + dye