Chapter 12 Part 2

Question 1

Sinus venosus

Answer 1

receives vessels called cardinal viens; enters into atrium and enters ventricle and then goes out ventral aorta; receives blood

Question 2

Sinoatrial valve

Answer 2

Blood enters atrium through sinoatrial valve, valve to prevent blood flowing backwards

Question 3

Atrium

Answer 3

oxygenated blood enters from body

Question 4

Atrioventricular valve

Answer 4

These valves (tricuspid on the right and mitral on the left) are located between the atria and ventricles, preventing backflow of blood into the atria during ventricular contraction.

Question 5

Ventricle

Answer 5

A chamber of the heart that pumps blood out to the lungs (right ventricle) or to the rest of the body (left ventricle) through strong contractions

Question 6

Bulbal and conal valves

Answer 6

These valves in the outflow tracts of the heart assist in directing blood flow and preventing backflow; they are part of the embryonic development of the heart.

Question 7

Conus arteriosus vs bulbus arteriosus

Answer 7

The conus arteriosus is a cone-shaped structure in the heart’s outflow tract, found in some vertebrates, acting as a preliminary pumping chamber. The bulbus arteriosus, primarily found in fish, is an elastic structure that helps maintain continuous blood flow from the heart to the gills or body.

Question 8

What is the aspiration effect?

Answer 8

o When the ventricle contracts, the volume occupied by the ventricle within the pericardial cavity is momentarily reduced
o Creates a negative pressure around the other chambers
o Causes them to expand
o Sucks in or aspirates blood from the returning veins

Question 9

Understand the cycle of contractions in blood to and from heart

Answer 9

o Returning venous blood/ Relaxation of the sinus venosus and atrium draws in blood via the hepatic and common cardinal veins

o Force of muscle contraction/Contraction of the atrium closes the sinoatrial valve and forces blood into the ventricle

o As the atrial walls relax again, blood enters the atrium

o Contraction of the ventricle forces blood through the bulbus arteriosus and distributes it to the aortic arches
o Cycle repeats

Question 10

Partial interatrial septum in lungfish

Answer 10

It partially divides the atrium into right and left chambers, helping to separate oxygenated and deoxygenated blood.

Question 11

Which vessel enters the left side of the atrium in lungfish

Answer 11

pulmonary vein

Question 12

Partial interventricular septum in lungfish

Answer 12

It helps in partially separating the ventricles, aiding in the separation of oxygenated and deoxygenated blood within the heart.

Question 13

Understand the path that oxygenated blood from the lungs takes to the body

Answer 13

o The pulmonary artery carries most of the deoxygenated blood to the lung

o Blood high in oxygen returning from the lung passes through the heart and then tends to enter the aortic arches without gills

o Blood is shunted directly to the general circulation

o When the lungfish breathes air, venous blood returning from systemic tissues flows through the heart and tends to be directed to the last aortic arch

Question 14

What are the functions of the ventricular trabeculae and the spiral valve?

Answer 14

Spiral valve: Oxygenated and deoxygenated streams depart by different exits to reach appropriate sets of arteries

Ventricular trabeculae: Separates streams of blood that differ in oxygen tension

Question 15

What is the function of the cavum venosum in turtles and squamates?

Answer 15

receives blood coming from the right atrium; Deoxygenated blood into there

Question 16

What is the function of the cavum pulmonale in turtles and squamates?

Answer 16

Venous blood from the right atrium enters the cavum venosum of the ventricle and crosses a muscular ridge to fill the cavum pulmonale momentarily

Question 17

What is the function of the cavum arteriosum in turtles and squamates?

Answer 17

Blood from the left atrium enters the deep cavum arteriosum

Question 18

Describe basic function of blood flow in turtles and squamates

Answer 18

Contraction of the ventricle squirts this blood through the interventricular canal, and then the blood departs via the left and right systemic arches

Upon ventricular contraction, most of this blood exits via the pulmonary artery

Question 19

Describe the orientation of the right and left systemic arches relative to the right and left ventricles in crocodilians

Answer 19

Right and left atria fill with deoxygenated systemic and oxygenated pulmonary blood

Right systemic arch goes to left ventricle, left systemic arch goes to right ventricle

Question 20

Crocodilian ventricle circulation

Answer 20

o Right and left systemic arch carries oxygenated blood, pulmonary artery carries doeoxygenated blood

Question 21

Describe crocodilian breathing

Answer 21

Oxygenated blood enters the left aortic arch via the foramen of Panizza

High pressure in the left systemic arch keeps the lunar valves at its base closed, leaving only the pulmonary route of exit for blood in the right ventricle

Question 22

Describe crocodilian diving

Answer 22

Right and left atria fill with deoxygenated systemic and oxygenated pulmonary blood

Ventricles fill

Resistance to pulmonary flow increases:
▪ Vasoconstriction of the vascular supply to the lungs, partial constriction of a sphincter at the base of the pulmonary artery, closure of aa pair of coglike, connective tissue valves

Blood in the right ventricle now tends to exit through the left aortic arch

Right systemic arch carrues oxygenated and deoxygenated, as well as does left systemic

Pulmonary artery carries little deoxygenated blood

Crocodilians able to stay under water around a half hour

Question 23

The pulmonary arch originates in which ventricle?

Answer 23

right ventricle, directing deoxygenated blood to lungs

Question 24

What is the Foramen of Panizza and what is its function?

Answer 24

a small opening between the left and right aortas that allows blood to shunt between them, aiding in the equal distribution of blood and helping to maintain blood pressure during various activities, like diving