Hearts

Question 1

What are the 4 tissue layers in a heart?

Answer 1

Pericardium, epicardium, myocardium, endocardium

Question 2

What does the pericardium do?

Answer 2

Sac that surrounds the heart

Question 3

What does the epicardium do?

Answer 3

Contains nerves that regulate the heart

Question 4

What does the myocardium do?

Answer 4

Contractile muscles

Question 5

What does the endocardium do?

Answer 5

The connective tissues surrounding the atria and ventricles

Question 6

What type of myocardium do fish and amphibians have?

Answer 6

Spongy

Question 7

How many chambers do bony fish hearts have?

Answer 7

4 compartments arranged in a series

Question 8

What are the 4 chambers in a bony fish heart? What is the order that blood flows through them?

Answer 8

Sinus venosus -> atrium -> ventricle -> bulbus arteriosus

Question 9

Which chamber is replaced by the conus arteriosus in elasmobranchs? Why?

Answer 9

The bulbus arteriosus. The conus is contractile and muscular, while the bulbus is elastic and non-contractile

Question 10

How many chambers do amphibian hearts have?

Answer 10

3, two atria and one ventricle

Question 11

How does blood flow through an amphibian heart?

Answer 11

Deoxygenated blood enters into the right atrium, and oxygenated blood enters into the left atrium. The ventricle pumps both into the conus arteriosus and into the pulmonary and systemic circuits

Question 12

Does mixing of oxygenated and deoxygenated blood occur in amphibians?

Answer 12

Yes

Question 13

How many chambers do non-crocodilian reptiles have?

Answer 13

5: the left atrium, the right atrium, the cavum arteriosum, the cavum pulmonale, and the cavum venosum

Question 14

How does blood flow through a non-crocodilian reptile heart?

Answer 14

The cavum pulmonale receives blood from the right atrium then pumps it to the pulmonary artery. The cavum arteriosum receives blood from the left atrium and pumps it to the right and left aorta

Question 15

What mechanism lets non-crocodilian reptiles bypass either the pulmonary or systemic circuit?

Answer 15

Shunt

Question 16

What are the two types of the shunt mechanism?

Answer 16

Right to left and left to right

Question 17

Which circuit is being bypassed in a right to left shunt? Why would the animal use this?

Answer 17

Bypasses the pulmonary circuit. Used during diving to send more blood to the tissues instead of to the lungs that aren’t doing anything

Question 18

Which circuit is being bypassed in a left to right shunt? Why would the animal use this?

Answer 18

Bypasses the systemic circuit. Used while resting on land

Question 19

How are crocodilian hearts different than the hearts of other reptiles?

Answer 19

It has 4 completely divided chambers, which 2 atria and 2 ventricles and no shunt mechanism

Question 20

How many chambers do mammalian hearts have?

Answer 20

4 chambers, 2 atria and 2 ventricles that are completely separated

Question 21

How does blood flow through mammalian hearts?

Answer 21

Deoxygenated blood flows from the vena cava into the right atrium then into the right ventricle, then through the pulmonary artery to the lungs. Oxygenated blood flows from the pulmonary veins into the left ventricle, into the left ventricle, into the aorta to the body