Lecture 19: Intro to Respiratory Function

Question 1

Purpose of respiratory system

Answer 1

delivery of O2 from the air to tissue and the removal of CO2 from tissues

also
- regulates pH
- vocalization
- defense against airborne pathogens

Question 2

respiratory system activity responds to changes in ______ activity

Answer 2

metabolic

Question 3

gas exchange occurs via simple _____

Answer 3

diffusion

-no proteins or ATP required

Question 4

Factors in Fick’s Law of Diffusion

Answer 4

• diffusion coefficient
• area over which gas diffuses
  -partial pressures of gas inside and out
  -distance gas has to diffuse

Question 5

what purpose does a high surface area serve in respiratory surfaces

Answer 5

greater alveolar surface area maximizes gas partial pressure gradients

Question 6

what are the 3 main types of respiratory surfaces in animals

Answer 6

1. air breathing terrestrial animals have INVAGINATED respiratory surfaces called LUNGS
2. nearly all water breathing aquatic animals have EVAGINATED surfaces called GILLS
3. Tracheae are air filled tubes in insects

Question 7

what is the primary job of the respiratory system

Answer 7

ventilation
- active process
- maintains gas gradients so that efficient diffusion of gases at the respiratory surface can occur
- ventilation combines with perfusion = circulation of blood over gas exchange surfaces

Question 8

what is perfusion

Answer 8

circulation of blood over gas exchange surfaces

Question 8

what are the 3 gas laws

Answer 8

1. total pressure of a mixture of gasses is the sum of the pressures of the individual gases (Dalton’s Law)
2. gases move from areas of higher pressure to areas of lower pressure
3. If the volume of a container of gas changes, then the pressure of the gas will change (Boyle’s Law)

Question 9

what is the partial pressure of a gas?

Answer 9

the pressure a single gas exerts in a mixture of gases

Question 10

what is the most abundant gas in the atmosphere?

Answer 10

nitrogen

Question 11

what % of O2 is in air

Answer 11

21%

Question 12

average atmospheric pressure at sea level?

Answer 12

760 mmHg

Question 13

what is atmospheric pressure

Answer 13

the barometric pressure of all gases in the atmosphere

Question 14

what is the relationship of barometric pressure and altitude

Answer 14

barometric pressure drops with altitude - inverse relationship

Question 15

how are fish gills specialized for gas exchange?

Answer 15

constant, unidirectional water flow (ventilation) maximizes PO2 on gill surfaces while perfusion minimizes PO2 on internal surfaces

Question 16

what are lamellae in fish

Answer 16

gill filaments covered by folds

• minimize diffusion path length b/w blood and water
  -sites of gas exchange that allows for the concurrent flow of H2O and blood

Question 17

what is concurrent exchange

Answer 17

when H20 and capillary blood flows in opposite directions

there is always a gradient

Question 18

what is the major challenge for gas exchange in terrestrial vertebrates

Answer 18

breathing air requires a moist respiratory surface with a large SA exposed to air —> lots of water loss

Question 19

what is tidal ventilation

Answer 19

bidirectional movement of air into and out of lungs by the same pathway

**mammals and most amphibians and reptiles

Question 20

what is tidal volume

Answer 20

the amount of air that moves in and out per breath

Question 21

how does tidal ventilation help reduce water loss?

Answer 21

allows for condensation

during inhalation, water evaporates in nasal passages,

during exhalation, water condenses (about 25%)

Question 22

what are the disadvantages of having tidal breathing

Answer 22

tidal breathing means no concurrent exchange (less efficient) and anatomical dead spaces in airway

-both reduce efficiency of respiratory system

Question 23

breathing in avians

Answer 23

air sacs receive air and keep air flowing through the lungs in a unidirectional flow

it takes two breaths to move air across the lung and out of the respiratory system

Question 24

what is the site of gas exchange within the gills

Answer 24

Lamellae