Lecture 10

Question 1

Amphibians, reptiles, birds and mammals have circulatory systems with

Answer 1

Pulmonary + systemic circuits

Question 2

Describe Amphibian hearts:

Answer 2

Three chambered heart: Two atria and One ventricle

Question 3

What happens due to the Amphibian heart having one ventricle?

Answer 3

Oxygenated and deoxygenated blood mixes in this one ventricle

Question 4

Describe Reptile hearts:

Answer 4

Five chambered heart: 2 Atria and 3 Ventricles (or Cavums - interconnected chambers)

Question 5

The Cavum Pulmonale functions to

Answer 5

Pump blood through the pulmonary circuit

Question 6

The Cavum Arteriosum functions to

Answer 6

Pump blood through the systemic circuit

Question 7

Describe Bird and Mammal hearts

Answer 7

Four chambered hearts

Question 8

What is the function of the right side of the heart?

Answer 8

Pumps deoxygenated blood to the lungs and then returns oxygenated blood from the lungs to the heart (via the pulmonary circuit)

Question 9

What is the function of the left side of the heart?

Answer 9

Pumps oxygenated blood through all the body tissues before returning deoxygenated blood to the heart (via the systemic circuit)

Question 10

Left ventricle pumps blood through this circuit so it is need of

Answer 10

Much more force compared to the right ventricle, so it has added muscle

Question 11

Pressure is higher in the

Answer 11

Systemic circuit

Question 12

Pressure is lower in the

Answer 12

Pulmonary circuit

Question 13

Why does pressure need to be lower in the Pulmonary circuit?

Answer 13

Pressure needs to be lower in the latter because blood does not need to travel far (destination is the lungs) and in the lungs, the blood vessels are very thin-walled due to gas exchange

Question 14

Why does pressure need to be higher in the Systemic circuit?

Answer 14

Pressure needs to be higher in the former because it carries blood to all parts of the body (besides the lungs), so the heart needs to contract very forcibly to ensure blood can reach places very far from the heart

Question 15

Oxygenated blood from lungs (via the pulmonary circuit) returns to the

Answer 15

Left atrium

Question 16

Deoxygenated blood from body (via the systemic circuit) returns to the

Answer 16

Right atrium

Question 17

What is the disadvantage to completely separated pulmonary and systemic circuits?

Answer 17

Circulatory system is inflexible

Question 18

Reptiles can selectively distribute blood between the two circuits with the use of a

Answer 18

Shunt

Question 19

What happens when there is a shunt?

Answer 19

The blood is prevented from entering the pulmonary circuit and recirculates only in the systemic circuit

Question 20

What is the shunt controlled with?

Answer 20

A valve in the heart (that separates the Cavum Venosum and Cavum Pulmonale)

Question 21

What happens when the valve for Reptiles is closed?

Answer 21

The blood can only flow through the systemic circuit

Question 22

What is the valve in reptiles controlled by?

Answer 22

Epinephrine

Question 23

Epinephrine levels decrease when

Answer 23

Underwater, resulting in closed valves

Question 24

Epinephrine levels increase when

Answer 24

Traveling, so valves open and blood can travel through both circuits