Human Bio Test 1 Revision
cell - A cell is the smallest unit that is capable of performing life functions.
Prokaryotic - Does not have a nucleus
Eukaryotic - Contain organelles surrounded by membranes and has a nucleus.
cell membrane - A semipermeable cell structure that controls which substances can enter or leave the cell.
cytoplasm - Thick fluid within the cell and all the structures suspended in it. it supports the organelles
Cytoskeleton - Network of protein fibres in the cytoplasm and is Responsible for both cell movement and stability
mitochondria - A rod shaped structure made up of a bilipid membrane with an inner fold (cristae) to increase surface area. Produces energy through aerobic respiration of glucose
Nucleus - Largest organelle surrounded by a nuclear membrane which has many pores to allow for the transport of materials. Directs cell activities and contains genetic information
Nucleolus - Found inside the nucleus and produces ribosomes
Endoplasmic Reticulum(ER) (rough) - A highly folded membrane structure that is continuous with the nuclear membrane. Involved in protein production. Provides a surface where reactions can occur and storage and transport of materials
Endoplasmic Reticulum(smooth) - Moves materials around in cell, produces lipids.
Golgi Body/Apparatus - Flat plate-like sacs with surrounding vesicles (small membrane sacs) often found near the nucleus
•Package, modify, store and secrete cellular products
Lysosome - A membrane bound bag of digestive enzymes. Involved in the destruction of foreign bodies and unwanted organelles within the cell.
Vacuoles - Membrane-bound sacs Involved in storage, digestion, and waste removal
Ribosomes - Small sphere-like structures found on rough ER and floating throughout the cell. Involved in making proteins
Centrioles - Composed of 2 sets of microtubules set at right angles to each other. Involved in cell division
Fluid mosaic model - model that describes the arrangement and movement of the molecules that make up a cell membrane.
Phospholipid bilayer - double layer of lipid molecules allows flexibility and protective barrier
Functions of cell membrane - a physical barrier, regulation of the passage of materials, sensitivity and support
phospholipid molecules - The main structure of the membrane is composed of phospholipid molecules, which are lipid molecules containing a phosphate group
chanel proteins - form a tunnel through which molecules may pass.
carrier proteins - change shape to allow molecules to pass through.
glyco proteins and glyco lipids - These function in cell recognition
integral proteins - span the membrane
peripheral proteins - are on one side or the other of the membrane
cholestoral - give the cell membrane extra support and as it disturbs the close packing of the phospholipids it keeps the membrane more fluid.
cellular fluid inside cell membrane. - The fluid inside the cell is called intracellular fluid and the fluid outside the cell is called the extracellular fluid.
cell theory - idea that all living things are composed of cells, cells are the basic units of structure and function in living things, and new cells are produced from existing cells
animal cell -
selective permeability (cell membrane function) - controls what enters and what leaves the cell.
physical barrier (cell membrane function) - barrier between intracellular and extracellular fluid.
sensitivity (cell membrane function) - contains receptors to monitor changes in fluid surrounding the cell.
support (cell membrane function) - giving support to whole cell as it is attached to microfilaments of the cells cytoskeleton.
vesicles - small membrane sacs that specialize in moving products into, out of, and within a cell
two ways materials pass through cell membrane - passive and active
passive - requires no energy
active - requires energy from the cell. this is because the cell has to transport substances against the concentration gradient.
passive methods - diffusion and carrier mediated
diffusion - random spreading out of molecules from a region of high concentration to low concentration.
net diffusion - movement of liquids or gases along a diffusion gradient, it continues until the concentration of the two areas become equal.
factors effecting diffusion - 1. steepness of concentration gradient, 2. molecular size, 3. temperature
steepness of concentration gradient - more steep= faster diffusion
molecular size - smaller molecules, faster diffusion
temperature - higher temperature, faster diffusion
hypertonic - higher solute concentration (salt water
hypotonic - low solute concentration (distilled water)
isotonic - when the concentration of two solutions is the same (ringers solution)
osmosis - Diffusion of water through a selectively permeable membrane
Facilitated diffusion - Movement of specific molecules across cell membranes through carrier proteins.
high concentration - when molecules are more crowded
steps of facilitated diffusion - 1. Molecule binds with carrier protein
2. Carrier protein changes shape
3. The molecule is transported through the cell membrane and protected from the hydrophobic
interior of the bilayer - 4. The molecule is released on the other side of the cell membrane and the carrier protein returns to original shape
net movement - overall movement of cells
plasmolysed - cells losing water
turgid - swollen
why alcohol and steroids can diffuse easily through cell membranes - they are fat soluble and can easily diffuse through lipid portions of the membrane.
why oxygen diffuses into cells and co2 out of cells - oxygen is higher concentrate outside of cell and co2 is higher concentrate inside of cell because of cellular respiration.
inclusions - Chemical substances that are not apart of the cell structure but found in the cytoplasm.
microtubules - Thick hollow tubes that make up the cilia, flagella, and spindle fibers. aid in transport and cell division.
difference between cilia and flagella - Cilia - Many, Short
Flagella - Few, Long
Relationship between gogli boddy, ribosomes and endoplasmic reticulum- proteins produced at the ribosomes pass through er channels to the golgi body.
methods of active transport -carrier mediated and vesicular transport
carrier mediated active transport -an energy-requiring mechanism whereby a substance moves from a region of lower concentration to a region of higher concentration, requiring the assistance of a carrier protein that becomes saturated.
vesicular transport - materials are enclosed in vesicles, bubble like strucutres surrounded by a membrane.
endocytosis - process by which a cell takes material into the cell by infolding of the cell membrane
phagocytosis - where materials are engulfed including solid particles. (cell eating)
pinocytosis - if the material is taken into a cell and is a liquid (cell drinking)
exocytosis - materials are passed to outside of the cell
how does exocytosis work - a vesicle is formed inside the cell, vesicle migrates to the cell membrane and fuses with it, the contents are then pushed to the extracellular fluid outside of the cell.
cell size - cells cant be too small, not eough room for organelles. be to big not enough nutrients.
the bigger the surface area - the more diffusion that can occur
the bigger the volume - more material needed to maintain cell
multicellular organisms - are a result of cells becoming to big and not having enough nutrients or excrete the waste fast enough.
benefits of multicellular - organisms grow in size, specialisation of cells.
tissue - groups of cells which are similar in structure and which perform common or related functions.
Muscle Tissue - composed of cells that have the special ability to shorten or contract in order to produce movement of the body parts.
skeletal muscle function - found attached to the skeleton and is responsible for the voluntary movement of bones
skeletal muscle structure - are arranged in bundles, multinucleated, Obvious striations
smooth muscle function - found in the lining of internal organs, controls the involuntary constriction in for peristalsis in the digestive system, constriction of blood vessels pupil constriction
smooth muscle structure - not striated, Have a spindle shape Each fibre contains
a single central nucleus
cardiac muscle function - Found in the heart, Responsible for the rhythmic contraction of the heart
cardiac muscle structure - Fibres are branching Have intercalated discs cells for a
synchronized contractions during heart beat, Single nucleus per fibre
nervous tissue function - Main component of the nervous system (ie brain , spinal column and nerves. Generates and transmits nerve impulses
nervous tissue structure - Cells have many long processes (extensions)Large central nucleus Two types of nervous tissue - neuron and glial cells
(neuroglial cells
Epithelial Tissue locations - •Lines the cavities, tubes, ducts and blood vessels inside the body
•Covers the organs inside body cavities
•Makes up the skin, covers the outside of the body
Epithelial tissue functions - Protection from physical & chemical injury, Protection against microbial invasion,Contains receptors which respond to stimuli, Filters, secretes & reabsorbs materials and Secretes fluids to lubricate structures.
Different types of epithelial tissue named based on their shape
Squamous Epithelium - flattened cells. Forms solid layer of cells which line blood vessels, body cavities & cover organs in body cavities. Forms epidermis (skin)
Cuboidal Epithelium - Roughly cube shaped, Line ducts in kidneys, etc, where reabsorption and secretory activities take place.
Columnar Epithelium - Column shaped (long & narrow), Line digestive tract where reabsorption & secretion occurs
connective tissue functions - • Connects, binds and supports structures,
-Tendons, ligaments, etc.
• Protects & cushions organs and tissues,
• Insulates (fat) and
• Transports substances (blood).
•Stores nutrients
connective tissue structure - cells are not tightly packed together
-cells are separated from each other by a large amount of non-cellular material called the matrix
-Matrix is made up ofa ground substance (usually a fluid) and protein fibres
connective tissue types - adipose, bone, cartilage blood, loose connective tissue, dense connective tissue.
adipose structure - Honeycomb appearance, Large amount of ground substance and less fibres
adipose function - Stores energy (fat), Insulates, Supports & protects organs
Bone structure - Tree ring-like appearance, Little ground material, Hard matrix
Bone function - Supports & protects, Mineral storage, Fat storage, Blood cell production
cartilage structure - Contains specialized cells called chondrocytes within the matrix
cartilage function - Gives shape, support and structure to other body tissues
Types of cartilage based on their structure
blood structure - Fluid connective tissue, No fibres, Only ground substance (plasma) and blood cells
blood function - Transports gases and nutrients Immune response (white blood cells)
loose connectiev tissue - Large amounts of ground substance and few fibres
Includes adipose and areolar and reticular tissue
Dense connective tissue - Contains more collagen fibres than loose CT so shows a greater resistance to stretching
Nutrient - any substance in food that is used for growth, repair or maintain our body
Organic Compound - large compounds that always contain the element carbon
Inorganic Compounds - substances that do not contain carbon
carbohydrate - compound made up of carbon, hydrogen, and oxygen atoms; major source of energy for the human body
categories of carbohydrates - monosaccharides (glucose), disaccharides (lactose), polysaccharides (glycogen)
fats and oils - contains hydrogen, carbon and oxygen, •The building blocks of fatty acids & glycerol, insulation, protection, energy store
triglycerides - one glycerol molecule attached to three fatty acid molecules
Proteins - Carbon, Hydrogen, Oxygen and Nitrogen. structural, metabolic, oxygen transport, protection and energy source in emergencies
amino acids- building blocks of proteins
nucleic acids - DNA and RNA
vitamins - Vitamins are inorganic substance essential in small quantities for normal health. They act as coenzymes or help regulate metabolic processes.
dietary minerals - Dietary minerals are the chemical elements required by living organisms.
metabolism - all the chemical reactions that take place in cells, and therefore in the organism of which the cells are a part.
catabolic metabolism - reactions in which large molecules are broken down into smaller ones
anabolic metabolism - reactions in which small molecules are built up into larger molecules.
enzymes - influence metabolism by controlling the chemical reactions that occur in the body
peptide bond - when two amino acids bond together, the carboxlyic acid group and amino group form a peptide bond and release a water molecule
dipeptides - shorter lengths of amino acids
polypeptides - with two amino acids joined
water - it is the fluid in which other substances are dissolved
how do enzymes work - lower activation energy by reducing stability of reactants or providing alternate pathways.
substrate - reactant that binds to enzymes
active site - where substrate fits into enzyme
lock key model - The model of the enzyme that shows the substrate fitting perfectly into the active site
lock key model process -1. active site of the enzyme attaches to substrate molecule to form an enzyme-substrate complex, 2. enzyme causes weakening of bonds to lower activation energy, 3. reaction proceeds and the enzyme is not used up.
activity of an enzyme - affected by general environmental factors
enzyme concentration - The higher the concentration of the enzyme, the faster the rate of the chemical reaction
•More enzymes means that they are more frequent collisions with the substrate
•Reaction rate keeps increasing until substrate concentration becomes a limiting factor
Substrate Concentration - Increasing substrate concentration increases the rate of reaction
•More substrate molecules come in contact with enzyme molecules
•Reaction rate does not keep increasing, it levels off as - all enzymes have active sites engaged
- enzyme is saturated
- maximum rate of reaction
Removal of Reaction Products -If the products of the reaction are not constantly removed the rate of the reaction slows because it becomes more difficult for the substrate molecules to come in contact with the enzyme molecules
Temperature - The temp that enzymes work best is known as their optimal temperature around 30-40 in humans. If too hot then it changes enzyme shape.
pH - Enzymes are very sensitive to pH and have an optimum pH in they will work most effectively. If too acidic it can change shape. Different parts of the body have different pH, so different enzymes have different optimum pH's
Co-enzymes and Co-factors - Cofactors (Ions or non-protein molecules) change the shape of
the active site so that the enzyme can combine with the substrate. - Non-protein organic compounds are cofactors called coenzymes
Enzyme Inhibitors- •Inhibitors either slow down or stop the activity of an enzyme.
•They often bond to the protein, changing the overall shape of the enzyme.
-Reversible:
•slow enzyme activity - often an interaction between the end product & the enzyme.
-Irreversible:
•bind tightly & permanently to the enzymes - destroying their activity.
Many poisons & drugs are enzyme inhibitors
Aerobic vs. Anaerobic - oxygen vs no oxygen
cellular respiration - organic molecules are broken down to release energy for all processes within a cell.
ATP (adenosine triphosphate) - Composed of a sugar ribose, nitrogenous base adenine, and a chain of three phosphate groups bonded to it. energy released from cellular respiration.
heat - As heat is constantly lost by the body, a continuous supply of heat is necessary in order to maintain body temperature. It is also released from cellular respiration.
how is ATP formed - ATP is formed when inorganic phosphate group is joined to a molecule adenosine diphosphate (ADP).
3 stages of cellular respiration - 1. glycolosis, 2. krebs cyle. 3. electron transport system
glycolosis - Breaking glucose into two molecules of a compound called pyruvate.
fermentation (anaerobic respiration) - If there is no oxygen, the pyruvic acid is converted to lactic acid by fermentation
Citric Acid or Krebs Cycles process - 1.pyruvate is converted to acetyl coenzyme A (acetly CoA)
2.The two molecules of acetyl CoA then enters the citric acid cycle (or Krebs Cycle)
3.The Krebs cycle (citric acid cycle) produces –2 ATP molecules from the 2 molecules of acetyl CoA
Electron Transport System - Electrons are passed between molecules, finally resulting in oxygen molecules forming water
blood - Fluid in which materials are transported
Vessels - A system of passages that allow the movement of the fluid
Heart - A pump that pushes the fluid through the vessels around the body
Blood - Blood is a connective tissue that is made up of a liquid part called plasma and a non-liquid part or formed elements consisting of cells and cell fragments.
Functions of the blood - •Transport of oxygen and nutrients to all body cells
•Removal of CO2 and other wastes from cells
•Transport of hormones (chemical messengers)
•Maintaining pH, water content, ion concentration
•Distributing heat and maintaining body temperature
•Protection (immune response)
•Clotting when vessels are damaged to prevent blood loss
Blood composition - PLASMA - 55%, CELLS - 45%
i.Plasma
Plasma is a clear, pale yellow liquid which comprises 55% of the whole blood.
Platelets (Thrombocytes)
•Fragments of cells made in the red bone marrow (no nucleus)
•Release chemicals to contract the blood vessel and reduce blood loss and stick to the fibrous network that forms during the blood clotting process
White blood cells (Leukocytes)
•Will fight infections as part of immune response, Made in the bone marrow and lymph tissue
Granulocytes
have a granular cytoplasm with a lobed nucleus
Agranulocytes
have a spherical nucleus and agranular cytoplasm
Red blood cells (Erythrocytes)
•Function to carry oxygen - carried on molecule called haemoglobin which is within each red blood cell
•Suited to their function of oxygen transport because:
- contain haemoglobin which is able to combine with oxygen
- do not have a nucleus to allow for more room for haemoglobin molecules and increases their flexibility
- Are biconcave disks to provide more surface area for oxygen exchange across the surface.
Transport of oxygen
Oxygen is not very soluble in water so only about 3% is carried in solution. The other 97% is carried in combination with haemoglobin molecules
oxyhaemoglobin
Haemoglobin and oxygen combine to form oxyhaemoglobin
when does oxyhaemoglobin break down
•Oxyhaemoglobin breaks down when oxygen concentrations are low such is in tissue fluid around cells
•Oxygen diffuses into the tissue fluid and then into cells
Transport of Carbon Dioxide
•7 to 8% is dissolved in the plasma
•22% combines with the globin part of the haemoglobin to form carbaminohaemoglobin
•70% carried in the plasma as bicarbonate ions (HCO3-)
clotting of blood
coagulation
Platelet Plug
smooth muscles cause vessels to constrict, platelet becomes sticky when exposed to collagen and Platelets stick to the rough surface of the damaged blood vessel
•Sticking platelets attract other platelets to form a plug
The Thrombin System
1) blood platelets and the injured cells release thromboplastin.
2)thromboplastin interacts with calcium ion and prothrombin to form thrombin
3)thrombin converts fibrinogen to long stretchy fibres to fibrins
4) the fibrin fibres form a mesh at the site of the wound that traps platelets and blood cells
5)within a few minutes the clot contracts, pulling edges of the broken vessel together
Serum
•the clear yellow fluid that oozes out of the clot - this is plasma minus the fibrinogen.
Thrombus
breaks loose it can lodge in a vital blood vessel in the heart or brain causing a heart attack or stroke
blood vessels
The transport of materials within the internal environment for exchange is facilitated by the structure and function of the circulatory system at the cell, tissue and organ level.
Types of Blood Vessels
arteries, veins, capillaries
arteries structure
•Have thick, elastic walls containing smooth muscle
•Ability to withstand high pressure
•Will expand under the surge of blood
•Can constrict/dilate
to change the diameter
•Small lumen (opening)
arteries function
•Take blood away from the heart to arterioles and finally capillaries in either the lungs or body tissue
•Blood is transported under high pressure
•Do not have valves
Veins structure
•Veins have thinner walls with thinner layers of smooth muscle and elastic fibers
•They carry blood under lower pressure
•Valves have flaps that prevent the back flow of blood
veins function
•They take blood from venules to veins and return it to the heart
•They have valves to prevent the back flow of blood
•These veins have to fight against gravity in lower limbs
Capillaries structure
•Only one cell thick
•No valves
capillaries function
•They take blood to all cells
•They enable the exchange of substances between blood and surrounding tissues
pressure
•Pressure is higher at the arterial end of the capillary than the venous end. •This pressure ensures materials move into the tissue fluid at the arterial end and out of the tissue fluid at the venous end
arterioles
smallest arteries
venules
small veins
Pulmonary Circulation
takes deoxygenated blood from the heart to the lungs and returns oxygenated blood to the heart
•The right ventricle is the pump for the pulmonary circulation
Systemic Circulation
takes oxygenated blood from the heart to all the tissues of the body and returns deoxygenated blood to the heart
-the left ventricle is the pump for the systemic circulation
double circulation
humans circulation
Major Arteries
Major Veins
another definiton of cellular respiration
an exothermic reaction which transfers energy from glucose and continuously occurs in living cells.
where does glycolosis occur
in the cytoplasm
where does krebs cycle occur
inner membrane of mitochondria
Periardium
holds the heart in place, but also allows the heart to move as it beats.
the atria
receive blood
the ventricles
receive blood
right side of the heart
right side collects blood from the body and pumps it to the lungs.
•The right atrium receives blood from the body and passes it to the right ventricle.
•The right ventricle pumps blood to the lungs.
left side of the heart
The left side receives oxygenated blood from the lungs and pumps it to the rest of the body.
•The left atrium receives blood from the lungs and passes it to the left ventricle.
•The left ventricle pumps blood to the body.
where are valves found?
between the atria and the ventricles are the atrioventricular valves (tricuspid and bicuspid)
structure of valves
valves are held in position by strong tendons, the chordae tendineae and attached by papillary muscles
semilunar valves
prevent the backward flow of blood from the arteries into the ventricles
how does blood flow change?
•by changing the output of blood from the heart
by changing the diameter of the blood vessels supplying the tissues
systole
The pumping phase of the cycle, when the heart muscle contracts.
diastole.
The filling phase, as the heart muscle relaxes.
Atrial systole,
contraction of the atria
ventricular systole
ventricles contract
cardiac output formula
Cardiac output (mL/minute) = stroke volume (mL) × heart rate (beats/minute)
formula for cellular respiration (aerobic)
C6 H12O6 + 6O 2 --> 6CO 2 + 6H2O + ATP
The lympathatic system
The lymphatic system functions to return tissue fluid to the circulatory system and to assist in protecting the body from disease
cardiovascular disease
Cardiovascular diseases (CVDs) or heart disease are a group of disorders of the heart and blood vessels.
Atherosclerosis
condition in which fatty deposits called plaque build up on the inner walls of the arteries, causing a blockage of blood flow.
What are the major risk factors for developing Cardio vascular disease
family history, smoking, lack of exercise.
heart attack
a condition in which blood flow to part of the heart muscle is blocked, causing heart cells to die
stroke
A sudden attack of weakness or paralysis that occurs when blood flow to an area of the brain is interrupted
Nasal Cavity (structure)
large structure with projections that is lined with hairs and epithelial tissue which produce mucus
Nasal Cavity (function)
1.connects external environment with the pharynx
2.The hairs and mucus to trap dirt particles and microbes
3.the projections (conchae) create turbulence in the air which helps the mucus trap dust and particles
4.Air is warmed and moistened
5.Specialised sensory cells give the sense of smell
The Pharynx (structure)
- region at the back of the mouth
- three sections
The pharynx (function)
•Passage for food and air
Epiglottis (structure)
a flap of cartilage
Epiglottis (function)
fits over the trachea when swallowing to prevent food entering the trachea (and moving down into the lungs)
Larynx (structure)
Vocal cords supported by cartilage
Larynx (function)
Sound production as air moves out of the lungs
Trachea (structure)
Tube from pharynx to bronchi - supported by C shaped rings of cartilage
Trachea (function)
- Cartilage holds the trachea open for air movement
- Ciliated epithelium along its length cleans the air with mucus
Bronchi (structure)
-Division of the trachea into the right and left lungs
-further divide into secondary and tertiary bronchi
Bronchi (function)
Air passage
Bronchioles structure
-very fine tubes with
walls of smooth
muscle
-end in groups of
air sacs (alveoli)
Bronchioles function
air passage
Alveoli structure
-Occur in clusters and very thin moist walls
•a large capillary network covers the sacs
Alveoli function
-Allow air to into very close contact with the blood so gas exchange can occur
Pleura structure
Membrane covering the lung and the internal thoracic cavity
Pleura function
Membrane produces pleural fluid which acts to reduce friction as the lung moves within the thoracic cavity
Diaphragm structure
Sheet of muscle which separates the thoracic cavity from the abdominal cavity
Diaphragm function
Aids in the ventilation of the lung
Intercostal Muscles structure
Muscles found between the ribs
Intercostal muscles function
Aids in the movement of the ribs for the ventilation of the lungs
·the efficient exchange of gases in the lungs is maintained by the actions of...
breathing, blood flow and the structure of the alveoli
What is the structure and function of the respiratory system at the cell, tissue and organ levels facilitated by
It is facilitated by exchange of gases between the internal and external environments of the body
The respiratory system
is the body's network of organs and structures responsible for taking in oxygen and expelling carbon dioxide, essential for cellular respiration and life.
•The lymphatic system
is a one-way drainage system that carries lymph from body tissues back to the general circulation
lymphatic system is made up of
A network of lymph capillaries and vessels, Lymph nodes located along the lymph vessels But no pump
Lymph Vessels
vessels that receive lymph from the lymph capillaries and circulate it to the lymph nodes. Lymph vessels also have valves to prevent the backflow of lymph
Lymph Nodes structure
•Bean shaped structures, Contains lymphoid tissue containing white blood cells (lymphocytes, macrophages) and plasma cells.
lymph nodes function
•Lymph nodes act as filters, trapping foreign particles and bacteria
Lymphatic Tissue
•Structures in the body that contain lymphatic tissue, but are not part of the lymphatic system and includes:
•Spleen
•Thymus
•Tonsils
lymph
lymph is fluid that may leak out from capillaries.
inhaling external intercostal muscle activity
•Contract, moving the rib cage and sternum upwards and outwards.
•The width of the chest increases from side to side and front to back.
diaphragm activity when inhaling
•Contracts and lowers
•These two movements has the effect of increasing the internal volume of the chest - creating an area of low pressure.
exhaling internal intercostal muscle
•Relax, moving the rib cage and sternum downwards and inwards. The width of the chest decreases from side to side and front to back.
diaphragm activity when exhaling
•Relaxes and is raised
•These two movements has the effect of decreasing the internal volume of the chest - creating an area of high pressure.
inhalation pressure
the expanding of the lungs creates a low pressure of oxygen, meaning the air moves from high pressure outside to low pressure inside.
exhalation pressure
the relaxing of the lungs forces air out of the high pressure environment to a low pressure environment outside of the body.
pathway of blood in the heart
Vena cava --> Right atrium-->tricuspid valve--> Right ventricle--> Pulmonary valve--> pulmonary arteries--> Lungs --> Pulmonary veins --> Left atrium --> mitral valve-->Left ventricle --> semilunar valve--> aorta --> Body cells
the blood coming to the alveoili is...
Blood coming to the alveoli from the pulmonary artery is deoxygenated- it has a low concentration of oxygen and also has a higher concentration of carbon dioxide because it has come from body circulation.
gas diffusion
Gases move by diffusion from a high concentration to a lower concentration
what is required for gas difussion
there must be a concentration gradient, that is a difference in gas concentration between the air in the alveoli and the blood in the capilllaries
How is concentration gradient for oxygen maintained
The constant flow of blood through the capillaries and The constant movement into and out of the alveoli as we breathe in and out
The lungs are suited to their gas exchange function because
-The alveoli give the lungs a huge surface area
-Each alveoli is well supplied with blood vessels
-The walls of the alveoli are very thin, so that gas molecules do not have far to travel
-The lungs are positioned deep inside the body to prevent excessive evaporation. The membrane must be moist because gases can only diffuse when they are dissolved in fluid
-The lung volume can be changed by movements of the respiratory muscles, so that air is made to flow into and out of the lungs
Emphysema (cause)
long term exposure to irritating particles
Emphysema effect
alveoli are damaged. They lose elasticity and often are replaced with fibrous tissue and may break down. Reduction of surface area so less gas exchange. Loss of elasticity means that the lungs are constantly inflated so breathing out requires voluntary effort.
emphysema treatment
can not be cured and the disease progresses. Treated with ventilation with oxygen and quitting smoking
lung cancer causes
smoking, exposure to asbestos, genetics, secondary cancer. Initiate a cancerous growth, a tumor that grows in an uncontrolled way.
lung cancer effects
- smoker's cough caused by the accumulation of mucous which then causes the rupture of alveoli. Emphysema develops. Cancerous growth can grow and obstruct air passage. Decreased gas exchange. Can also lead to secondary cancer
lung cancer treatment
chemotherapy, radiation, surgery to kill the cancer cells
pneumonia cause
infection of the lungs caused by bacteria, viruses, fungi or other organisms.
pneumonia effect
The inflammation from the infection causes fluid and mucous to fill alveoli thus reducing surface area for gas exchange. Breathing is also difficult
pneumonia treatment
medication to cure infection
Tuberculosis treatment
bacterium, effect is same as pneumonia, treatment is antibiotics.
Asthma cause
foreign particles such as animal skins, feathers and pollen grains which cause an allergic response
asthma effect
muscles that surround the bronchioles go into spasm causing narrowing of the air passages and difficulty breathing. Irritation also causes the secretion of excessive mucous and this also restricts the movement of air. Less gas exchange
asthma treatment
Relievers are used during an attack and are bronchiole dilators which widen the airways. Preventive medication is used for long term treatment to reduce the frequency of attacks.