Chapter 16: Respiratory Physiology

Question 1

What are the Alveoli and how many are there in the lungs?

Answer 1

Tiny air sacs that exchange gas in the lungs. There are estimated 300 million air sacs. They provide a larger surface area.

Question 2

Why are Macrophages in alveoli?

Answer 2

Pulmonary macrophages can phagocytose particles that enter the lungs.

Question 3

What is surfactant? Why do we need it?

Answer 3

It is a biological soap that is secreted into the alveoli by type II alveolar cells made up of phospholipids. Surfactant is interspersed between water molecules reducing H bonds, reducing the surface tension.

Question 4

What is another name for the Cricoid Cartilage

Answer 4

Adam’s apple

Question 5

Where is the glottis and vocal cords (true and false cord)?

Answer 5

In the larynx. The glottis is a hole and the true vocal cord closely surrounds it. The false vocal cord is in the ventricular fold and the epiglottis is a skin flap that goes over the glottis

Question 6

What is Lung Compliance and how can it be symbolically represented?

Answer 6

It is the change in lung volume per change in transpulmonary pressure. Change V/Change P. A given transpulmonary pressure, in other words, will cause greater or lesser expansion, depending on the compliance of the lungs.

Question 7

What decreases lung compliance?

Answer 7

The infiltration of lung tissue with connective tissue proteins, a condition called Pulmonary Fibrosis. If the lungs were filled with concrete, transpulmonary pressure would not increate so the compliance would be zero.

Question 8

What is the Law of Laplace?

Answer 8

The pressure created by surface tention should be greater in the smaller alveolus than in the larger alveolus. This implies that (without surfactant) smaller alveoli would collapse and emply their air into larger alveoli.

(2 x surface tension)/radius=pressure created by surface tension.

Question 9

What does surfactant do?

Answer 9

It becomes interspersed between water molecules to reduce the hydrogen bonds between water molecules to reduce surface tension. Made up of phospholipids.

Question 10

What is a restrictive disorder? Give examples

Answer 10

the vital capacity is reduced to below normal. However, the FEV is normal. EX: pulmonary fibrosis, emphysema

Question 11

What is an obstructive disorder? Give examples

Answer 11

The VC is normal b/c lung tissue is not damaged. However, Expiration is difficult (FEV). Obstructive disorders are diagnosed via testing FEV. If FEV is below 80%, there is a presence of obstructive pulmonary disease. EX: Bronchoconstriction, asthma

Question 12

What is emphysema?

Answer 12

It is a restrictive disease that destroys alveolar tissue resulting in fewer alveoli»> reducing surface area for gas exchange. This results in the ability of bronchioles to remain open during expiration–> collapsing the bronchioles.

Smoking can cause this.

Question 13

What is Chronic Obstructive Pulmonary Disease (COPD)?

Answer 13

Chronic inflammation of airways and destruction of alveolar walls. caused by cigarette smokes free radicals.

Question 14

What is Dalton’s Law?

Answer 14

It is the total pressure of gas mixture (like air) is equal to the sum of the pressures that each gas in the mixture would exert independently. Like a dry atmosphere=760mmHg. N2+O2+CO2=760mmHg

Question 15

What is Partial Pressure?

Answer 15

The pressure that a particular gas in a mixture exerts independently.

Question 16

What conditions create an environment that could cause Oxygen Toxicity?

Answer 16

Breathing 100% oxygen at one or two atmospheres pressure can be safely tolerated for a few hours. Being over oxygenated can cause damages to the nervous system by the OXIDATION OF ENYMES.

Question 17

What is Decompression Sickness AKA “the bends” ?

Answer 17

If a diver surfaces slowly, a large amount of nitrogen can diffuse through the alveoli and be eliminated in the expired breath. Bubbles of N2 gas form in the tissue fluids and enter the blood. This process in analogous to the formation of carbon dioxide.

Question 18

What forms the Rhythmicity Center?

Answer 18

The respiratory rhythm is generated by a loose aggregation of neurons in the ventrolateral region of the medulla oblongata which forms the rhythmicity center for the control of automatic breathing.

Question 19

What does the apneustic center promote? How?

Answer 19

Appears to promote inspiration by stimulating the inspriatory neurons in the medulla.

Question 20

What does the pneumotaxic center do?

Answer 20

seems to antagonize the apneustic center and INHIBIT inspiration. This center is closest to the Pons and midbrain.

Question 21

What are Chemoreceptors sensitive to?

Answer 21

changes in the pH of brain interstitial fluid and cerebrospinal fluid, AND in the P-co2, pH and P-o2 of the blood. A lowered pH (more acidic) causes less O2 which raises CO2 levels.

Question 22

Where are central chemoreceptors?

Answer 22

In the medulla oblongata

Question 23

Where are peripheral chemoreceptors?

Answer 23

In the aorta and the carotid arteries

Question 24

What is the pathway of the regulation of ventilation by the CNS?

Answer 24

See Fig. 16.26 on page 555

Question 25

What is Oxygens effect in blood?

Answer 25

The oxygen content of the blood decreases slowly b/c of the large “reservoir” of oxygen attached to hemoglobin.

The content of blood, on the other hand, is not significationly increased by hyperventilation (b/c HEMOGLOBIN in arterial blood is 97% SATURATED with OXYGEN even during normal ventilation.

Question 26

What is Carbon Dioxide effect in the blood?

Answer 26

During hyperventilation, conversely, blood P-co2 quickly falls and pH rises because of the excessive elimination of carbonic acid.