Final: Gas Exchange in Animals (Respiratory System) Slides

Question 1

Functions of the respiratory system (5)

Answer 1

• Provides oxygen to cell
• Eliminates carbon dioxide
• Regulates pH level
• Speech production
• Defense against foreign bodies (non specific immunity)

Question 2

Total atmospheric pressure and partial pressure of O2

Answer 2

760 mmHg; 160 mmHg

Question 3

Organs of the respiratory system (10)

Answer 3

Nasal cavity, oral cavity, pharynx, larynx, trachea, primary bronchus, secondary bronchus, tertiary bronchus, bronchiole, alveoli

Question 4

What comprises the bronchiole tree?

Answer 4

Primary, secondary, tertiary bronchus

Question 5

Which airways are in the conducting zone?

Answer 5

Trachea, primary through tertiary bronchi, bronchioles

Question 6

Conducting zone

Answer 6

Air just passing through, can’t go anywhere

Question 7

Which airways are in the respiratory zone?

Answer 7

Respiratory bronchioles, alveoli (interact with capillaries)

Question 8

Respiratory zone

Answer 8

Air can exchange/interact with blood

Question 9

Which three types of cells make up an alveolus?

Answer 9

Alveolar type I cells, alveolar type II cells, macrophages

Question 10

Function of alveolar type I cells

Answer 10

Very thin epithelial cells; form wall of alveoli

Question 11

Function of alveolar type II cells

Answer 11

Release surfactant that prevents lung collapse and helps make breathing easy

Question 12

Parts of lungs (3)

Answer 12

Chest wall, pleural sac, lung

Question 13

Pleural sac function

Answer 13

Membrane that sticks lungs to inside of rib cage (allows lungs to move with ribs)

Question 14

Types of pressure (3)

Answer 14

Atmospheric pressure (Patm), alveolar pressure (Palv), intrapleural pressure (Pip)

Question 15

What is alveolar pressure?

Answer 15

Pressure of gases in alveoli

Question 16

What causes intrapleural pressure?

Answer 16

Induced by pleural sac

Question 17

Boyle’s Law

Answer 17

Pressure is inversely proportional to volume

Question 18

What happens to pressure and volume during inspiration?

Answer 18

Volume of lungs increases, pressure decreases

Question 19

What happens to pressure and volume during expiration?

Answer 19

Volume of lungs decreases, pressure increases

Question 20

Muscle movement during inspiration

Answer 20

External intercostal muscles push out, diaphragm pushes down

Question 21

What is passive expiration?

Answer 21

Elastic recoil of lungs (doesn’t use muscles)

Question 22

Muscle movement during active expiration

Answer 22

Internal intercostals contract; abdominal muscles contract (pushes diaphragm up)

Question 23

What is compliance and how does it relate to lungs?

Answer 23

Ease of changing the volume when pressure is changed; lungs have high compliance and expand easily

Question 24

How do gases cross the lung/blood media?

Answer 24

Diffusion: capillaries and alveoli are lined with simple squamous epithelium

Question 25

How is oxygen transported in the blood? Give breakdown.

Answer 25

• Dissolved in plasma and erythrocytes (1.5%)

- Bound to hemoglobin (98.5%)

Question 26

How many oxygens can each hemoglobin bind?

Answer 26

4

Question 27

Steps (overview) of oxygen transport

Answer 27

1. O2 crosses from alveoli to plasma
2. Moves from plasma to erythrocytes where it binds to Hb
3. Transported to cells where it is unloaded the same way

Question 28

Oxygen movement at lung level

Answer 28

High [O2] in alveoli, low [O2] in plasma; hemoglobin favors loading and O2 moves from alveoli to blood

Question 29

Oxygen movement at tissue level

Answer 29

High [O2] in plasma, low [O2] in tissue; hemoglobin favors unloading and O2 moves from blood to tissue

Question 30

What affects Hb-Oxygen binding?

Answer 30

BPG (2,3-bisphosphoglyceric acid), temperature, acidity

Question 31

How is carbon dioxide transported in the blood? Give breakdown.

Answer 31

• Dissolved in plasma (~10%)
• Hemoglobin (~30%) - less affinity than for O2
• Bicarbonate (~60%) - a buffer

Question 32

What allows most CO2 to travel in a buffer?

Answer 32

Carbonic anhydrase

Question 33

CO2 movement at tissue level

Answer 33

Opposite of O2: High [CO2] in tissue, low [CO2] in blood so CO2 goes to blood

Question 34

CO2 movement at lung level

Answer 34

Opposite of O2: High [CO2] in blood, low [CO2] in alveoli so CO2 goes to alveoli

Question 35

How is inspiration initiated?

Answer 35

Stimulating the respiratory muscles: diaphragm and external intercostals

Question 36

For inspiration, what initiates the stimulation to the respiratory muscles?

Answer 36

Medullary centers and pons (nervous system)

Question 37

Types of chemoreceptors for respiration

Answer 37

Peripheral (outside brain) and central (inside brain)

Question 38

What are the peripheral chemoreceptors?

Answer 38

Carotid bodies and aortic bodies

Question 39

Homeostatic mechanism for respiration

Answer 39

Receptors are chemoreceptors (carotid and aortic bodies), control center is medulla and pons, effector is diaphragm and nearby muscles (external intercostals)