Biol 320 Exam 3 Taylor

What happens when you exhale?

Diaphragm relaxes and moves up by intercostal muscle, volume of lung decreases and pressure increases

What happens when you inhale?

Diaphragm contracts and moves down, ribs go up by external intercostal muscles, volume of lung increases and pressure decreases

What forces air into the lungs?

Air moves from high pressure to low pressure (gradient)

What is the gradient created by our body during respiration?

A point in which the pressure in the body is lower than the pressure in the atmosphere, air keeps entering temporarily until the pressures are equal

What is boyle's law?

Pressure is inversely proportional to volume

What is atmospheric pressure?

Force exerted by gasses in the air surrounding us (constant at 760mmHg)

Atmospheric pressure at sea level

760 mmHg

Respiratory (intra-pulmonary) pressures have what three types?

Negative, positive, neutral

What happens to atmospheric pressure during inhalation?

atmospheric pressure is always consistent, but pressure becomes negative and decreases in the lungs during inhalation

What are the mechanisms of inhalation?

PI is lower than atmospheric pressure (Pb), Air flows down the pressure gradient

What are the mechanisms of exhalation?

Diaphragm goes up, ribs go down, smaller volume, PI is higher than Pb, air flows down the pressure gradient

What are the four factors affecting respiration?

Muscles, lung compliance, airway resistance, surfactant effect/surface tension

What muscles are involved in ventilation?

diaphragm and intercostal muscles

What is lung compliance?

The ease of which lungs can be stretched, affected by elasticity (elastic recoil) and surface tension of lungs (alveoli)

What allows lungs to stretch?

Elastic fibers

What is airway resistance?

Airway radius, affected by passive forces, contractile activity of smooth muscle, and mucus secretion

What is the surfactant effect?

Surface tension caused by water in alveoli, pulmonary surfactant reduces this

Why can we hold our breath?

Some air is trapped in our lungs as a reserve, surfactant keeps the alveoli open all the time to maintain some amount of air in the lungs by preventing it from collapsing

What is surfactant made of?

phospholipids

What are the functions of type II cells?

Produce surfactant, and produce mother cells for type I

What are the 3 functions of surfactant?

Stabilize alveoli, maintain dryness of alveoli, reduce the work of breathing

How does surfactant stabilize alveoli?

Reduces surface tension, goes between H and O ions

How does surfactant maintain dryness of alveoli?

Prevents the edema of the alveoli

What is the work of breathing?

Effort required to expand and contract lungs, normally requires 3% of total energy expenditure of the body for quiet breathing

What is partial pressure?

the pressure of a single type of gas in a mixture of gases

What is total pressure?

sum of all partial pressures

What is Dalton's law?

Behavior of nonreactive gasses in a mixture of these gasses

What is Henry's Law?

Behavior of gasses when they contact liquids

What is ventilation?

Movement of air into and out of the lungs, regulated by diameter of airways

What is perfusion?

Flow of blood in pulmonary capillaries, regulated by diameter of blood vessels

What is external respiration?

Result of partial pressure differences in O2 and CO2, oxygen diffuses across respiratory membrane to capillaries, CO2 diffuses out of capillaries into alveolus

What is internal respiration?

Partial pressure of O2 in tissues are lows, O2 diffuses from blood into tissues, CO2 diffuses from tissues to blood

What is loading?

when hemoglobin binds to oxygen in the lungs

What is unloading?

when oxyhemoglobin drops off oxygen in the tissues

Why do we need hemoglobin?

Oxygen needs a carrier due to solubility, 3% of oxygen can dissolve in water, but 97% needs hemoglobin to carry them because they cannot dissolve

How much O2 can a healthy male transport?

200mL

How much O2 can a healthy female transport?

174mL

What happens during right shift?

Reduced affinity, increased temp, increased 2-3 DPG, Increased H+

The amount of O2 bound to hemoglobin is ____________ related to the partial pressure of O2

Directly

What is the oxyhemoglobin dissociation curve?

Shows the O2% that is bound to Hb at each O2 pressure, steep slope and flat portion between 70 and 100 mmHg of O2

How does exercise affect Hb saturation?

During exercise, Hb can carry about 10 more mmHg of O2

How does pH affect the oxyhemoglobindissociation curve?

if pH increases the curve will shift left

Where does the conversion of CO2 to bicarbonate occur?

Red blood cells

Why doesn't the conversion of CO2 to bicarbonate occur in white blood cells or platelets?

Because RBCs produce the enzyme required for the process

What is the chloride shift?

Movement to bring more ions into the RBCs to balance the increase of H+ ions and keep RBCs neutral

What is the Haldane effect?

O2 effect on CO2 transport, increased ability of blood to carry CO2 when hemoglobin is deoxygenated, a high PO2 decreased the affinity of Hb for CO2

How is respiration controlled?

Sensors, Effectors, and the Central controller

What are sensors?

Chemoreceptors, lungs and other receptors can sense if you stop breathing

What is the central controller?

pons, medulla, other parts of brain

What are effectors?

respiratory muscles

List 4 effectors

Diaphragm, intercostal muscles, abdominal muscles, accessory muscles

What are chemoreceptors?

Specializes tissues that respond to a change in the chemical composition of the blood or other fluid, responds to pH or ESF, exists in the lung and other organs

What is the neural control of lung mechanics?

Respiratory center is the brainstem, which includes the medulla oblongata and the pons

What are the effects of aging on respiration?

Vital capacity and maximum minute ventilation decreases, ability to remove mucus from passageways decreases, gas exchange across respiratory membrane in reduces, elasticity decreases

What is the embryonic origin of the respiratory system?

Endoderm

What is the pathway for the digestive system?

mouth → pharynx → esophagus → stomach → small intestine (duodenum, jejunum, ileum) → large intestine (cecum, colon, rectum, anus).

What is mechanical digestion?

Physically breaking down food substances into smaller particles to more efficiently undergo chemical digestion

What is chemical digestion?

Further degrade the molecular structure of the ingested foods by digestive enzymes into a form that is absorbable into the bloodstream

What other systems contribute to the digestive system?

Respiratory and circulatory systems carry oxygen to the digestive system

What are MALT and Peyer patches?

Part of the immune system, lymphs in the small intestine that catch bacteria and support the digestive system

What does the integumentary system form?

Vitamin D

How does the urinary system aid the digestive system?

Reabsorption of calcium, iron, sodium, potassium, and vitamin D

What are the accessory structures of the digestive system?

teeth, tongue, salivary glands, gallbladder, liver, pancreas

What holds the digestive organs in place?

parietal and visceral peritoneum

What is the nerve supply of the digestive tract?

Myenteric plexus and submucosal plexus

What is the myenteric plexus?

Neurons that are responsible for peristaltic movement of the bowels

What is the submucosal plexus?

Situated within the gut wall (from esophagus to the rectum), functions by secretions

What is the general function of the mouth?

Chewing/mastication

What is the general function of the pharynx and esophagus?

Propelling fenction

What is the general function of the stomach?

Acidic environment not good for bacteria, pepsin (for protein), HCl for low pH

What is the general function of the small intestine?

Food absorption

What enzymes are secreted from the intestine?

Lipase, amylase, sucrase, lactase, maltase, aminopeptidase, carboxypeptidase

What is the general function of the liver?

Emulsifies fats/lipids

What is the general function of the pancreas?

Produces enzymes regulated for digestion of proteins like trypsin and trypsinogen

What are the three subdivisions of the pharynx

nasopharynx, oropharynx, laryngopharynx

What is the esophagus?

C-shaped cartilages because it is located behind the trachea and needs to expand

What are the 3 major phases of the digestive system?

Ingestion, propulsion/deglutition, chemical/mechanical digestion

What are the key terms of propulsion?

Movement by peristalsis, food then moves to stomach, small intestine, then large intestine

Is the mouth chemical or mechanical digestion?

both

Is the esophagus chemical or mechanical digestion?

mechanical

Is the intestine chemical or mechanical digestion?

Both

What is the major site of absorption?

small intestine

What are the detailed roles of the stomach?

Muscular action

What are the 4 regions of the stomach?

cardia, fundus, body, pylorus

What is submucosa?

connective tissue

What is stomach mucosa made of?

Parietal cells

What are parietal cells?

Exocrine cells that secrete HCl, Intrinsic Factor, and Bicarbonate

What is the function of bicarbonate?

To kill the bacteria not killed by HCl and neutralize the stomach

What are cheif cells?

Exocrine, secrete digestive enzymes (pepsin and pepsinogen) that cleave proteins into smaller pieces

What are mucous neck cells?

secrete thin, acidic mucus of unknown function

What are enteroendocrine cells?

endocrine cells in the epithelium of the digestive tract, control stomach secretions and motility, produces gastrin and histamine

What is chyme?

Fluid which passes from the stomach to the small intestine (consisting of gastric juices and food)

What is responsible for gastric motility?

Peristalsis

What is a gastric ulcer?

Ulcer formed when acidic or alkaline food goes into the small intestine, if stomach does not stop secretions

What are internal stimuli of the digestive system?

Chemoreceptors detect not enough amino acids, fatty acids, or monosaccharies

What are 3 important digestion regulation hormones?

Gastrin, somatostatin, histamine

What does gastrin do?

Stimulates movement of stomach and intestine muscles to stimulate the secretion of enzyme

What does somatostatin do?

Opposite of gastrin, inhibits secretion of enzymes in the stomach and small intestine, or inhibits peristalsis action

What does histamine do?

Stimulates secretion of HCl

Name some mechanical functions of the stomach

Mixing wave, gastric emptying