34 - Gas Exchange

Question 1

Gastrovacular Cavity

Answer 1

Allow exchange of materials from the cavity with cells that line the cavity.

Mixing up waste and nutrients is not very effective.

Limits type of structure seen in organisms

Only cells that line the gastrovascular cavity can absorb and secrete waste.

No complex structures

Question 2

Circulation System - contain

Answer 2

Contains pump – the heart.

Circulatory fluid = (open hemolymph) (closed blood)

Vessels to contain fluid

Question 3

What type of circulation does the heart pump hemolymph through partial vessels to the body cavity?

Answer 3

Open

Question 4

In what type of circulation does the heart pump blood through the vessel, and blood never leaves the vessels

Answer 4

Closed

Question 5

Single circulation

Answer 5

2 chamber Heart
Fish

Question 6

Double Circulation

Answer 6

Gas Exchange with the Environment

Pulmocutaneous circuit (amphibians)

Pulmonary circuit (mammals)

Distributed around the body

Question 7

Heart chambers 3

Answer 7

Reptiles / Amphibians
A single ventricle that pumps blood through both circuits

Question 8

Heart chamber 4

Answer 8

mammals’ birds – no mixing of O2 – rich & O2 depleted (more efficient ectotherms)

Two ventricles – each pump through one circuit

Question 9

The heart is a specialized pump steps
1.
2.
3.
4.

Answer 9

Start in atria

Signals delayed at the AV node

A bundle of branches passes signals to heart’s apex

Signals spread through ventricles

Question 10

3 Main types of blood vessels

Answer 10

Arteries
Capillaries
Veins

Question 11

Carry blood away from the heart

Thicker smooth muscle layers – to withstand the pressure of heart-pumping blood

High blood pressure and velocity of blood

Answer 11

Arteries

Question 12

exchange of nutrients, waste and gasses between blood and surrounding tissue

Thin walls allow the exchange

All diffusion-based no active transport.

The high surface area allows for organisms to maximize the exchange.

Low velocity and blood pressure

Allow diffusion to happen.

Answer 12

Capillaries

Question 13

Carry blood back to the heart – have valves to prevent blood from back flowing (low pressure in the veins)

Lower pressure and slightly higher velocity than capillaries

Answer 13

Veins

Question 14

All gas exchange structures have

Answer 14

Large SA to V ratio - Maximize exchange (diffusion)

Generally, Moist or Wet

Question 15

Fish Gills / Rayfinned fishes -integrated w/ circulation system
WHAT MAKES IT WORK

Answer 15

Gill filaments are arranged so the flow of water is in the opposite direction as the flow of blood (oxygen transfer)

Counter Current Exchange - Required to efficiently extract oxygen

Question 16

Tracheal system (insects not integrated into circulation)

Answer 16

Air tube that contacts every cell in the organism for gas exchange to occur

Question 17

Lungs where end? / Birds?

Answer 17

Branching airways that end in alveoli – little sacks embedded in capillaries where the gas exchange occurs

Birds – have one-way lungs that are very efficient.

Question 18

Hemoglobin - What it is

Answer 18

tetramer (4 protein strands) of 2 alpha 2 beta
Red = Oxygenated
Blue = deoxygenated

Question 19

Hemoglobin role

Answer 19

4 oxygen-binding sites

red blood cells full of hemoglobin

Carbon monoxide also binds to hemoglobin and doesn’t come off (kills you by taking up receptors instead of oxygen)

Binds oxygen at the lungs/gills but release it in the tissue

Fetus steal oxygen from mother by producing better hemoglobin molecules.