Chapter 46: Gas Exchange in Animals

Question 1

What are the functions of the respiratory system?

Answer 1

-Provides oxygen
   For ATP production
-Eliminates carbon dioxide
-Regulates pH levels 
-Speech production
-Defense against foreign bodies

Question 2

What is ventilation?

Answer 2

Gas exchange.

Take in O2, get rid of CO2

Question 3

How does oxygen travel to the cell?

Answer 3

Via diffusion in the blood

Question 4

What is the composition of air?

Answer 4

21% Oxygen, 78% Nitrogen, 1% other

Question 5

What is the atmospheric pressure?

Answer 5

760 mmHg

Question 6

What organs make up the respiratory system?

Answer 6

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

Question 7

What are the conducting zones?

Answer 7

the airways

Question 8

What are the respiratory zones?

Answer 8

-Small portion of the bronchioles and the alveolus
 Oxygen makes it into the body
-Where the oxygen molecules make it into the blood
-You have a lot of alveolus and capillaries
 And they are thin and heavily vascularized
• The thinner, the faster the rate of diffusion

Question 9

What occurs during Alveolar perfusion (delivery of blood to the capillary bed)

Answer 9

• O2 is very high (concentration) in the alveoli and low in the blood vessels
• High level of CO2 in the blood on its way to the lung. Goes to the alveoli

Question 10

What is an alveolus?

Answer 10

Alveolus is a thin air sac that gets filled with O2

Question 11

What does a Type I Alveolar cell do?

Answer 11

Form the walla of alveoli

Question 12

What does a Type II Alveolar cell do?

Answer 12

Secrete surfactant

Question 13

What make up the lungs?

Answer 13

chest wall, pleural sac, and lung

Question 14

Why is breathing so easy for us to do?

Answer 14

• Due to the pressure volume change within our lungs

- Boyle’s law: volume and pressure and inversely proportional

Question 15

What is inspiration?

Answer 15

Volume increases and pressure decreases
•Muscles: diaphragm and the external intercostal muscle
o When the diaphragm contracts, they push down, the external intercostal pushes out

Question 16

What is expiration?

Answer 16

volume decrease and pressure increases
-Lower atm pressure while air is being pushed out of the lungs
-Passive expiration
o Elastic recoil of the lungs
-Active expiration
o Contraction of internal intercostal
o Contraction of abdominal muscles (causes diaphragm to be pushed up)

Question 17

How do gases cross?

Answer 17

By diffusion: both capillaries and the alveoli are lined with simple squamous epithelium

Question 18

What is blood?

Answer 18

a connective tissue made of cells and fluid (plasma) and erythrocytes

Question 19

How is blood transported in the blood?

Answer 19

-Dissolved in the plasma and erythrocytes (1.5%)
o Erythrocytes are packed with hemoglobin and red blood cells
 Hemoglobin (iron), biconcave discs
• Hemoglobin attracts oxygen (negatively charged)
o Oxygen travels from high to low concentration (from the alveoli to the blood)
 One it is in the cells, it has lower concentration in the blood
 Are flat to maximize surface area
 Red blood cells don’t have organelles, they have hemoglobin

-Bound to hemoglobin (98.5%)
o Found in red blood cells

Question 20

Describe oxygen transport

Answer 20

-Oxygen crosses from the alveoli to the plasma
 From the plasma to the erythrocytes where it binds to Hb
• Oxygen is then transported to cells where it is unloaded in the same way
-The more active our cells are, the more oxygen is delivered
-Use oxygen to generate ATP

Question 21

What affects Hb-Oxygen binding?

Answer 21

-BPG (2,3 bisphosphoglyceric acid)
 Increase in BPG triggers blood cells to release more oxygen
-Temperature
 Heat promotes the release of more oxygen
-Acidity
 Switching to anaerobic exercise-More unloading of oxygen
-Metabolic activity of the tissue affect the amount of oxygen that needs to be delivered

Question 22

How is carbon dioxide transported?

Answer 22

-Dissolved (10%)
-Hemoglobin (30%)
-Bicarbonate (60%)
 Converted to carbonic anhydrase, which facilitates the conversion of CO2 to bicarbonate

Question 23

What regulates how we inhale/exhale?

Answer 23

-The brain regulates how we inhale/exhale

 The medulla oblongata contains the respiratory center (cluster of neurons that control respiration rate)

Question 24

What is the function of the phernic nerve?

Answer 24

-Phrenic nerve controls and stimulates the diaphragm
 When the action potential fires, we get respiration
 When the neurons stop the action potentials, we get exhalation

Question 25

How is breathing homeostatically regulated?

Answer 25

-Inspiration is initiated by stimulating the respiratory muscles
•Diaphragm and external muscles
-The stimulation is initiated in the medullary centers and the pons

Question 26

Role of chemoreceptors in the respiratory system

Answer 26

-Sense the concentrations of O2 and CO2
 When there is high concentration of O2 and little CO2 in the lungs, you want to breathe less
• And vice versa
-Central chemoreceptors (in the brain)
-Peripheral chemoreceptors (outside the nervous system
 Carotid bodies (MEASURE)
• Located by the neck, connected to the brain
 Aortic bodies

Question 27

What are the receptors, effectors, and control center of the respiratory system?

Answer 27

The carotic and aortic bodies are the receptors. The medulla oblongata is the control center. The diaphragm and intercostal muscles are the effectors

Question 28

What is a squamous epithelium? Where are they found?

Answer 28

Found in alveoli and capillaries, they facilitate the transport of gases