2.3: Respiratory Physiology

Question 1

True or False: Humans do not have a storage area for gases and must continually acquire oxygen and rid the body of carbon dioxide.

Answer 1

True

Question 2

What are the 4 steps in Respiration?

Answer 2

1. Breathing: includes inspiration (breathing air in) and expiration (breathing air out)
2. External respiration: gas exchange with the environment at a respiratory surface
3. Internal respiration: gas exchange between blood and tissue fluid
4. Aerobic cellular respiration: production of ATP (adenosine triphosphate) in cells

Question 3

Describe Step 1 in Respiration.

Answer 3

1. Breathing: includes inspiration (breathing air in) and expiration (breathing air out)

Question 4

Describe Step 2 in Respiration.

Answer 4

2. External respiration: gas exchange with the environment at a respiratory surface

Question 5

Describe Step 3 in Respiration.

Answer 5

3. Internal respiration: gas exchange between blood and tissue fluid

Question 6

Describe Step 4 in Respiration.

Answer 6

4. Aerobic cellular respiration: production of ATP (adenosine triphosphate) in cells

Question 7

Gas exchange takes place by the physical process of ______.

Answer 7

diffusion

Question 8

For diffusion to be effective, the gas-exchange region must be what 3 things?

Answer 8

moist
thin
large in relation to the size of the body.

Question 9

The effectiveness of diffusion is enhanced by extensive vascularization of the lungs, and delivery of oxygen to cells is promoted by an oxygen carrying molecule, such as ______.

Answer 9

hemoglobin

Question 10

___1___ is a rich source of oxygen compared to ___2___; however, it does have a ___3___ effect on respiratory surfaces.

Answer 10

1. Air
2. water
3. drying

Question 11

A human loses about ______ of water per day when the air has a relative humidity of only 50%.

Answer 11

350 ml

Question 12

Answer 12

View of alveolus, magnified to show external respiration

Question 13

True or False: Humans have lungs that are elaborately subdivided into small passageways and spaces.

Answer 13

True

Question 14

It has been estimated that human lungs have a total surface area at least ______ the skin’s surface area.

Answer 14

50x

Question 15

To keep the lungs from drying out, ___1___ is ___2___ as it moves through passageways leading to the lungs.

Answer 15

1. air
2. moistened

Question 16

______ happens as the lungs move air into the respiratory tract (inhalation) and out of the respiratory tract (exhalation).

Answer 16

Ventilation

Question 17

Ventilation happens as the lungs move air into the ___1___ and out of the ___2___.

Answer 17

1. respiratory tract (inhalation)
2. respiratory tract (exhalation)

Question 18

A ______ environment is created inside the lungs by the pleural space, which means that the pressure inside this space is less than that of the atmosphere.

Answer 18

negative pressure

Question 19

During ______, the rib cage lifts superiorly and anteriorly to open up and expand the lungs.

Answer 19

inhalation

Question 20

A muscle called the ___1___ is a dome-shape at rest. The ___1___ is flattened as it contracts, pulling the lungs open.

Answer 20

1. diaphragm

Question 21

As the thoracic cavity expands and lung volume increases, the density of the gases filling the lungs ______.

Answer 21

decreases

Question 22

When the air pressure outside of the lungs is ______ than inside (where there is negative pressure), air will naturally flow into the lungs.

Answer 22

greater

Question 23

During ______, the rib cage is lowered, the diaphragm rises, the thoracic pressure increases, and air will naturally move out of the lungs where the pressure is lower.

Answer 23

exhalation

Question 24

True or False: The lungs completely empty during each breathing cycle.

Answer 24

False. The lungs DO NOT completely empty during each breathing cycle.

Question 25

What is incomplete ventilation?

Answer 25

The lungs not completely emptying during each breathing cycle.

Question 26

Because of the incomplete ventilation method, the air entering ___1___ with used air remaining in the lungs. This helps to ___2___ and ___3___.

Answer 26

1. mixes 2. conserve water 3. maintain a constant temperature

Question 27

______ primarily accounts for the exchange of gases between the air in the alveoli and the blood in the pulmonary capillaries.

Answer 27

Diffusion

Question 28

Atmospheric air contains little ___1___, but blood flowing into the pulmonary capillaries is ___2___.

Answer 28

1. carbon dioxide, 2. almost saturated with this gas

Question 29

GRADIENT DIFFUSION: Atmospheric air contains little carbon dioxide, but blood flowing into the pulmonary capillaries is almost saturated with this gas. Therefore, carbon dioxide naturally diffuses out of the blood into the alveoli and then ultimately exhaled. This pattern is the reversed for oxygen. Blood coming into the pulmonary capillaries is oxygen-poor, and the alveolar air is oxygen rich. This causes the oxygen to naturally diffuse into the capillaries.

Question 30

Answer 30

Red blood cell with hemoglobin to bind and carry oxygen in the blood

Question 31

______ helps to assist natural diffusion.

Answer 31

Hemoglobin

Question 32

Most oxygen entering the blood combines with ___1___to form ___2___.

Answer 32

1. hemoglobin (found in red blood cells) 2. oxyhemoglobin

Question 33

Each hemoglobin molecule contains ___1___ chains, and each chain is folded around an iron-containing group called ___2___, which is the iron that forms a loose association with oxygen.

Answer 33

1. four polypeptide 2. heme

Question 34

True or False: Since there are less than 10 million hemoglobin molecules in each red blood cell, each cell can only carry about 40 million molecules of oxygen.

Answer 34

False. Since there are about 250 MILLION hemoglobin molecules in each red blood cell, each cell can carry MORE THAN ONE BILLION molecules of oxygen.

Question 35

In the tissues, some hemoglobin combines with carbon dioxide to form ______.

Answer 35

carbaminohemoglobin

Question 36

______, helps to remove carbon dioxide from the tissues.

Answer 36

carbaminohemoglobin

Question 37

Approximately 30% of carbon dioxide is transported this way.

Answer 37

carbaminohemoglobin

Question 38

Most of the carbon dioxide is transported in the blood in form of the ______.

Answer 38

bicarbonate ion

Question 39

___1___ is an enzyme in red blood cells that combines carbon dioxide and water to form the ___2___.

Answer 39

1. Carbonic anhydrase 2. bicarbonate ion

Question 40

Carbonic anhydrase is an enzyme in red blood cells that combines ___1___ and ___2___ to form the bicarbonate ion.

Answer 40

1. carbon dioxide 2. water

Question 41

Approximate ___% of carbon dioxide is carried freely in the blood.

Answer 41

10%