Cardiovascular system Pre-lab and recall questions

Pericardial cavity

A small potential space located between the two layers of the serous pericardium that contains serous fluid

Ms.F. visited her physician for a routine physical. During the exam, she explained that over the last two weeks, she had been feeling much more tired than normal and occasionally felt short of breath. Knowing that women usually present with atypical symptoms of a heart attack, her physician ran some diagnostic tests, and found that Ms. F. was indeed having a heart attack. a) Imaging studies showed that Ms. F. had blockages in both her right marginal artery and her anterior interventricular artery. What parts of the heart would be affected by these blockages? b) Ms. F.'s heart attack damaged one of her papillary muscles. What is the normal function of a papillary muscle? Predict the consequences of a malfunctioning papillary muscle.

A) These blockages would affect the anterior right and left ventricles (the anterior interventricular artery) and the lateral part of the right atrium and right ventricle (the marginal artery). B) The papillary muscles pull the chordae tendineae taut during ventricular contraction, which prevents prolapse of the atrioventricular valves into the atria. Dysfunction of a papillary muscle would prevent some of the chordae from functioning properly, which could lead to valvular prolapse.

Where do arteries carry blood? Is this blood generally oxygenated or deoxygenated? Does this rule have any exceptions? If yes, where?

Arteries carry blood away from the heart. Arteries generally carry oxygenated blood. Yes, the exceptions are the pulmonary and umbilical arteries.

Pulmonary trunk

Artery that carries deoxygenated blood from the right ventricle to the lungs

Pulmonary trunk

Bring(s) deoxygenated blood to the lungs

Pulmonary veins

Bring(s) oxygenated blood to the left atrium from the lungs

While in the hospital recovering from her heart attack Ms.F. developed a condition known as atrial fibrillation, in which the myocytes of the atria depolarize and contract individually. How are the cells of the heart supposed to contract? (Hint: Think about the functions of the intercalated discs.) Why would it impair the functions of the heart as a whole to have cardiac myocytes contracting individually?

Cardiac myocytes should contract as a unit, first in the atria, then in the ventricles. The intercalated discs couple cardiac myocytes electrically and physically, which allows them to contract simultaneously. This is important, as it allows the chambers to form a unified contraction that will eject blood. When individual myocytes contract, there is no unified contraction, and blood is not ejected from the chamber.

Endocardium

Endothelium that lines the chambers and valves of the heart

Chordae tendineae

Fibrous cord(s) that attach(es) to valves

Chordae tendineae

Fibrous cords attached to the cusps of the atrioventricular valves that anchor the cusps to the papillary muscles

Papillary muscles

Fingerlike muscular projections from the ventricles

Visceral pericardium

Inner layer of the serous pericardium

Pulmonary valve: how does it differ structurally from the tricuspid valve? What is the function of this valve?

It has three half-moon shaped cusps not attached to chordae tendineae. It prevents the backflow of blood from the pulmonary trunk to the right ventricle.

Mitral valve: What is the function of this valve? How does its structure differ from that of the pulmonary and tricuspid valves?

It prevents the backflow of blood from the left ventricle to the left atrium. It has two cusps.

A condition known as pulmonary hypertension is characterized by high blood pressure in the pulmonary circuit. Which chamber of the heart would this condition most directly affect, and why?

It would most directly affect the right ventricle, as this chamber is pumping into the pulmonary circuit. The higher pressure in the pulmonary circuit makes the right ventricle have to pump harder, and can cause it to enlarge and fail as a result.

Left ventricle: How does it compare with the thickness of the right ventricle? Why is there a difference?

Its wall is much thicker. The left ventricle pumps against much higher pressure and therefore requires a higher muscle mass.

Ventricles (right and left)

Large inferior chambers of the heart that eject blood into the arteries

Inferior vena cava

Large vein that carries blood from the inferior half of the body to the right atrium

Superior vena cava

Large vein that carries blood from the superior half of the body to the right atrium

Aorta

Largest artery in the body that carries oxygenated blood from the left ventricle into systemic circulation

Myocardium

Layer of the heart composed of cardiac muscle tissue

Mitral valve

Located between the left atrium and left ventricle

Aortic valve

Located between the left ventricle and the aorta

Tricuspid valve

Located between the right atrium and the right ventricle

In the heart dissection you performed, you noted the muscular walls of the ventricles. The walls of the atria, however, were much thinner. Why do you think the ventricular walls are so much thicker than the atrial walls?

Much of the blood from the atria drains into the ventricles simply by the force of gravity. As a result, there isn't much muscular force needed to push blood from the atria to the ventricles. In contrast, the ventricles are pumping against gravity and into higher-resistance blood vessels, so they need to generate more force when they contract. This causes them to have greater muscle mass.

Papillary muscles

Muscular projections from the ventricular walls that pull the chordae tendineae taut to prevent prolapse of the cusps of the atrioventricular valves

Parietal pericardium

Outer layer of the serous pericardium

Fibrous pericardium

Outermost layer of the sac surrounding the heart that anchors the heart to the surrounding structures

Aortic valve: Is it structurally more similar to the pulmonary valve or the mitral valve? What is the function of this valve?

Pulmonary valve It prevents the backflow of blood from the aorta to the left ventricle.

Atria (right and left)

Small superior chambers of the heart that receive blood from veins

The condition known as ventricular septal defect is characterized by the presence of a hole in the inter ventricular septum. How would this condition affect the normal pattern of blood flow? What effect would this have on the oxygenation of the blood?

Some of the blood could flow directly from the right ventricle to the left ventricle instead of flowing intothe pulmonary trunk. This would cause some of the blood to bypass the lungs and, therefore, not become oxygenated. As a result, the blood that the left ventricle pumps into the aorta, and out to the systemic circuit, is only partially oxygenated.

Tracing blood through the heart starting with Inferior/Superior venae cavae

Start: Inferior/Superior venae cavae ➜ right atrium ➜ tricuspid valve ➜ right ventricle ➜ pulmonary valve ➜ pulmonary trunk ➜ pulmonary arteries ➜ pulmonary arterioles ➜ pulmonary capillaries ➜ pulmonary venules ➜ pulmonary veins ➜ left atrium ➜ mitral valve ➜ left ventricle ➜ aortic valve ➜ End: Aorta

When the pericardium fills with blood, it produces a condition called cardiac tamponade, which can be rapidly lethal. Why is this condition so dangerous? (Hint: Consider the structure of the fibrous pericardium.)

The fibrous pericardium is not distensible, which causes the blood to put pressure on the heart, constricting it and reducing its ability to contract.

Serous visceral pericardium

The inner layer of the serous membrane around the heart that is part of the heart wall; also called the epicardium

Myocardium

The layer of the heart wall composed of cardiac muscle tissue and a fibrous skeleton

Where does the left atrium pump blood when it contracts?

The left atrium pumps blood into the left ventricle.

Where does the left ventricle pump blood when it contracts?

The left ventricle ejects blood into the aorta.

Serous parietal pericardium

The outermost layer of the serous membrane around the heart that is functionally fused to the fibrous pericardium

Where does the right atrium pump blood when it contracts?

The right atrium pumps blood into the right ventricle.

Where does the right ventricle pump blood when it contracts?

The right ventricle ejects blood into the pulmonary trunk.

Tricuspid valve: How many flaps do you see What is the function of this valve?

There are three flaps. It prevents the backflow of blood from the right ventricle to the right atrium.

Aortic valve

Three-cusped structure between the left ventricle atrium and aorta that prevents the flow of blood back into the left ventricle

Tricuspid valve

Three-cusped structure between the right atrium and right ventricle that prevents the flow of blood back into the right atrium

Pulmonary valve

Three-cusped structure between the right ventricle and pulmonary trunk that prevents the flow of blood back into the right ventricle

Mitral (bicuspid) valve

Two-cusped structure between the left atrium and left ventricle that prevents the flow of blood back into the left atrium

Where do veins carry blood? Is this blood generally oxygenated or deoxygenated? Does this rule have any exceptions? If yes, where?

Veins carry blood toward the heart. Veins generally carry deoxygenated blood. Yes, the exceptions are the pulmonary and umbilical veins.

Pulmonary veins

Veins that carry oxygenated blood from the lungs to the left atrium

Fill in the blanks: The two main branches of the left coronary artery are the ________ _________ artery and the ________ _________ .

anterior interventricular circumflex artery

The tricuspid and mitral valves are known as the chordaetendineae. semilunar valves. coronary valves. atrioventricular (AV) valves.

atrioventricular (AV) valves.

Fill in the blanks: Cardiac muscle cells are also known as _______ ________ . Adjacent cells are joined together by ________ _______ , which allow the heart to _______ ___ _ _____ .

cardiac myocytes intercalated discs contract as a unit

The main vein that drains the coronary circulation is the superior vena cava. pulmonary vein. small cardiac vein. coronary sinus.

coronary sinus.

The arteries of the systemic circuit carry ______________ blood, and the arteries of the pulmonary circuit carry ______________ blood. oxygenated;deoxygenated oxygenated; oxygenated deoxygenated; deoxygenated deoxygenated; oxygenated

oxygenated;deoxygenated

The function of the papillary muscles is to pull open the semi lunar valves. pull the chordae tendineae taut. pull open the atrioventricular valves. pull the semilunar valves closed.

pull the chordae tendineae taut.