Lecture 12: Respiration (Midterm II)

Question 1

What are the concentrations of the 3 main gases that make up the atmosphere?

Answer 1

Nitrogen - 78%
Oxygen - 21%
Carbon Dioxide - 0.04%

Question 2

explain the concept of partial pressure

Answer 2

amount of total atmospheric pressure contributed by a gas that is in the gas mixture

Pgas = C * BP

Question 3

explain how O2 concentration changes with elevation

Question 4

water vs. air as respiratory media

Question 5

what is the importance of a large surface area in respiratory membranes

Question 6

What are the 3 properties that determine how much O2 is available

Answer 6

1. concentration of gas in the medium
2. partial pressure of gas in the gas mixture
3. type of respiratory medium

Question 7

concentration

Answer 7

• amount of gas in a mixture
• mainly O2, N2, and CO2 in earth atmosphere

Question 8

partial pressure

Answer 8

amount of total atmospheric pressure contributed by a gas that is in the gas mixture

Question 9

Does concentration of gas change anywhere on earth?

Answer 9

no

Question 10

true or false: partial pressure changes with atmospheric pressure

Answer 10

true

Question 11

is there more O2 available in water or in air

Answer 11

more O2 in air; less in water

Question 12

gases diffuse in which method

Answer 12

they diffuse down pressure gradients; so from higher partial pressure to lower pressure

Question 13

what are the requirements for animals exchange of gases

Answer 13

large, moist respiratory surfaces such as air or water

Question 14

Gills in aquatic animals are

Answer 14

outfoldings of the body that create a large surface area for gas exchange

Question 15

what process moves the respiratory medium over the respiratory surface by convection

Answer 15

ventilation

Question 16

Fish gills use which type of gas exchange system; explain it

Answer 16

countercurrent exchange; blood flows opposite to water and blood is less saturated with O2 than water

Question 17

explain tracheal systems in insects

Answer 17

• system consists of tiny branching tubes that penetrate the body
• tracheal tubes supply O2 directly to body cells
• respiratory and circulatory systems are separate
• larger insects ventilate their tracheal system to meet O2 demands

Question 18

Importance of the lungs and how they are derived

Answer 18

• lungs are derived from the gut during development
• circulatory system transports gases between the lungs and rest of the body
• size and complexity of lungs depend on animal’s characteristics

Question 19

In the mammalian respiratory system, what conveys air to the lungs

Answer 19

a system of branching ducts

Question 20

In the mammalian respiratory system, air inhaled through the nostrils passes through the ______ via the ______________ where gas exchange occurs

Answer 20

pharynx; larynx, trachea, bronchi, bronchiole, alveoli

Question 21

In the mammalian respiratory system, exhaled air passes through the _________ and creates ?

Answer 21

vocal cords; sounds

Question 22

In the mammalian respiratory system, what is the purpose of surfactants

Answer 22

they coat the surface of the alveoli; they keep it moist and open by reducing surface tension, like a soap

Question 23

In air breathing vertebrates what ventilates the lungs

Answer 23

breathing

Question 24

Explain the difference between amphibian, birds, and mammals lungs

Answer 24

come back to this

Question 25

amphibian lungs

Answer 25

- use positive pressure to inflate - air forced down trachea - during exhalation air is expelled by elastic recoil

Question 26

bird lungs

Answer 26

- lungs don't inflate - gas exchange occurs when air sacs force air through parabronchi - passing air through system takes 2 breaths - birds have very efficient gas exchange in lungs - gas exchange occurs in both exhalation & inhalation

Question 27

Mammals lungs

Answer 27

- **negative pressure breathing** pulls air into the lungs - as rib muscles & **diaphragm** contract, lung volume increases - **tidal volume** is volume of air inhaled with each breath - maximum tidal volume is the **vital capacity** - after exhalation a **residual volume** of air remains in the lungs

Question 28

**Explain the steps of gas exchange in the mammalian respiratory system**

Answer 28

1. O2 delivered to aveoli during inhalation 2. O2 crosses alveolar membrane by diffusion to the blood 3. blood loses O2 to capillary beds as it travels through system 4. CO2 diffuses into blood at capillary beds 5. CO2 is carried through blood to the lungs 6. CO2 diffuses 7. CO2 exhaled to atmosphere

Question 29

In the alveoli, O2 and CO2 diffuse where

Answer 29

O2 to the blood, CO2 into the air

Question 30

Be able to explain how most oxygen is carried through the blood by hemoglobin

Answer 30

1. first O2 that binds causes the molecule to change shape 2. shape change allows the second molecule of O2 to bind more easily 3. causes the thrid tetramer to bind O2 easily 4. fourth one binds O2

Question 31

Explain the effect of pH on binding and O2 availability

Question 32

what is O2 affinity ?

Answer 32

having an attraction for

Question 33

what are respiratory pigments

Answer 33

proteins that transport oxygen, and **greatly increase** the amount of oxygen blood can carry

Question 34

arthropods and molluscs have ____ with copper as the oxygen-binding component

Answer 34

**hemocyanin**

Question 35

most vertebrates and some invertebrates use ____ contained within erythrocytes

Answer 35

hemoglobin

Question 36

a single hemoglobin molecule can carry how molecules of O2

Answer 36

four

Question 37

the process of binding in a non-linear fashion is

Answer 37

**cooperativity**

Question 38

what does the hemoglobin dissociation curve illustrate ?

Answer 38

a small change in partial pressure of O2 can result in a **large change ** in delivery of O2

Question 39

is hemoglobin always saturated?

Answer 39

no; becomes unsaturated through high energy use

Question 40

explain the Bohr shift

Answer 40

1. CO2 produced during cellular respiration **lowers blood pH ** and **decreases affinity of hemoglobin** for O2 2. happens because CO2 + H2O --> HCO3- which lowers pH of blood --> lowers affinity of hemoglobin

Question 41

the bohr shift can be utilized to

Answer 41

decrease the affinity of hemoglobin when it is advantageous to release O2