Chapter 42: Circulation and Gas Exchange

Question 1

What is one of the evolutionary adaptations of animals?

Answer 1

Gas exchange with the environment through specialized surfaces that are extensively branched or folded.

Question 2

Define body

Answer 2

An arrangement that protects delicate tissues from abrasion or dehydration and allows for streamlined body contours

Question 3

Why are the tissues of the surfaces branched and folded?

Answer 3

To maximize surface area for gas exchange

Question 4

What does it mean for an animal to be endothermic?

Answer 4

They are warmed mostly by heat generated by metabolism

Question 5

What does it mean for an animal to be ectothermic?

Answer 5

They gain most of their hear from external sources

Question 6

___________ (endotherms/ectotherms) can maintain stable body temperature even in the face of if large fluctuations in the environmental temperature.

Answer 6

Endotherms

Question 7

What does the circulatory system do?

Answer 7

Moves fluid between each cell’s immediate surroundings and body tissues where exchange with the environment occurs

Question 8

What happens in an open circulatory system?

Answer 8

Hemolymph (interstitial fluid that bathes body cells) is not confined to the blood vessels.

• mostly sedentary animals have this because of low flow rates
• insects also have this

Question 9

What happens in a closed circulatory system?

Answer 9

Hemolymph (interstitial fluid that bathes body cells) is within the blood vessels.

• blood flows in a continuous circuit through the body under pressure generated by the heart
• vertebrates, earthworms, annelids, squid, octopuses etc have this

Question 10

Explain how the heart works using the concepts of pulmonary circulation and systemic circulation.

Answer 10

Pulmonary circulation

1. Blood (from body) enters right atrium
2. Blood enters right ventricle
3. Blood is pumped from right ventricle to lungs

Systemic circulation

4. Blood (from lungs) enters left atrium
5. Blood enters left ventricle
6. Blood is pumped from left ventricle to body

Question 11

What is single circulation?

Answer 11

When the blood passes through the heart once in each complete circuit through the body

• occurs in fishes, rays and sharks

Question 12

What is double circulation?

Answer 12

When the blood passes through the heart twice in each complete circuit through the body

• occurs in mammals, amphibians and birds

Question 13

What type of blood circuit do amphibians have?

Answer 13

Pulmocutaneous circuit (double)

• blood travels to skin and lungs

Question 14

What type of blood circuit do mammals have?

Answer 14

Pulmonary circuit (double)

• blood goes to lungs