Questions From Heart Anatomy Lecture (A&P II- Exam I)

{possible short answer} In what ways are cardiac muscle tissue and skeletal muscle tissue similar? How is cardiac muscle tissue different?

(Short answer will most likely ask for a list of -Like skeletal muscle, cardiac muscle is striated and made up of myofibrils (with sarcomere.) -But unlike it, cardiac muscle cells (aka, cardiocytes): -are quite small (50-100 Um in length) -usually uni-nucleate. -have more mitochondria and the mitochondria are HUGE (make up 25% of cell volume!) -Lots of myoglobin (stores oxygen) -even more richly vascularized than average skeletal muscle. -Cardiocytes have wider, but shorter T-tubules and less sarcoplasmic reticulum than skeletal muscle. -Additionally, in skeletal muscle, the trigger for contraction is the release of calcium from the SR. But in cardiac muscle it also involves the influx of calcium into the cell through these larger T-tubules. -Cardiocytes are typically branched (unlike simple cylinders of skeleton muscle.) -And are connected to several other cardiocytes at special sites called intercalated discs.

What are the muscular ridges on the inner surfaces of the ventricles called?

trabeculae carneae

What is meant by the coronary circulation? Why is it needed?

-Coronary Circulation is the blood supply of the heart. -Needed because the heart always needs oxygen and nutrients.

From where do the two coronary arteries emerge?

-Emerge from the base of the Aorta. -They emerge very close to the aortic semi-lunar valve.

What is the function of pericardial fluid?

- Pericardial fluid is a fluid that reduces friction between the beating heart and the surrounding tissues.

Where specifically in the body is the heart located? What side of the heart do we mostly see in the anterior view?

- The heart is directly posterior to the sternum; roughly from the 3rd costal cartilage to the end of the body of sternum. -The heart lies in the anterior mediastinum. (Space between the lungs) -The heart is also rotated such that in an anterior view of the body, we see mainly the right atrium and right ventricle.

What causes a heart attack? How is it different from angina pectoris?

--Caused by long-term insufficent supply of blood to one or more parts of the heart muscle that suddenly kills a patch of the myocardium. -The poor blood supply itself is due to a blood clot somewhere in the coronary arteries. --Different because its cause by SHORT-term slow down or blockage of blood flow. -e.g. A partially blocked coronary artery constricts temporarily.

Explain how and when most of the blood actually enters the coronary circulation

--When the left ventricle contracts, it forces blood into the aorta, but little blood flows into the coronary arteries. -Why? Cusps of valves block them. -Ventricles relax, the stretched walls of the aorta relax and recoil which results in elastic rebound which pushes blood further into the coronary arteries.

Describe the order in which the four chambers of the heart contract

-1st atria contracts simultaneously. Then ventricles contract (also simultaneously.)

Why are chordae tendinae and papillary muscles unnecessary for the semilunar valves?

-Because the pressure they need to withstand is much less (afterall, the ventricles are relaxed.)

What is another name for a mature cardiac muscle cell?

-Cardiomyocytes

Where is the foramen ovale found? What is its function? How does it differ from the fossa ovalis?

-Found in the interatrial septum that connects the right and left atria. -Functions to bypass the lungs (beneficial before birth.) -Differs in that, the Foramen ovale is an actual hole between the two atrium while the Fossa ovalis is just simply a closed spot that becomes a shallow depression that persists into adult hood.

What is meant by carditis? How may it affect the heart valves?

-Inflammation of the heart -Perhaps createsmore pressure on the valves, thus, making them leak blood in the wrong places.

What are intercalated discs? What are the two major types of junctions that are part of the intercalated disc, and what is the function of each type?

-Intercalated disks are special junctions between cells. They connect several other cardiocytes. -the type of junctions that are part of the intercalated disc are, desmosomes and gap junctions. -The desmosomes resist stretching and help transfer the force of contraction from cell to cell. -the gap junctions allow small molecules and ions to flow between the cells. Thereby electrically connecting the cells. (Side notes)(Gap junctions) -E.g. Action potential can quickly travel from cell to cell. -in a sense, they allow all the cardio cytes of the atria (or ventricles to act like a single huge cell.)

How does the cross-sectional shape of the right and left ventricles differ?

-Left ventricle is round in cross-sectional shape. -The right ventricle has a pouch-like shape.

Describe the function of the chordae tendinae and the papillary muscles?

-Play a vital role in holding the atrioventricular valves in place while the heart is pumping blood. (prevents leakage.) prevent over extension of cusps.

As applied to heart valves, what is meant by "regurgitation"?

-Regurgitation is each time ventricle contracts, there would be back flow into the atria.

What's the difference between an atrium and an auricle?

-The auricle (OR "ear") is when the atrium (both right and left) are not filled with blood in the outer portions of each atrium and instead deflates into a wrinkly flap.

Is the heart as situated in the body straight up and down or is it tilted? If tilted, how so?

-The heart is tilted. - Such that the apex (inferior, point tip) is about 3 inches left of the midline of the body.

Which ventricle has especially thick walls? Why?

-The left ventricle -Allows the the left ventricle to pump with much greater pressure than the right. -This is because the right ventricle only has to pump blood at low pressure a short distances (6inches) But the left has to pump blood throughout the systemic circuit. (Requires roughly 5x the pressure.)

What do we call the fibrous sac (bag) that surrounds the living heart?

-The pericardium

What specifically is the function of the atrioventricular (AV) valves? Do they block blood during ventricular relaxation or contraction?

-They prevent blood from being forced BACK into the atria when ventricles contract.(Helps pumping efficiency.) -Ventricular contraction.

What specifically is the function of the semilunar valves? Do they block blood during ventricular relaxation or contraction?

-To prevent the blood from leaking back into the ventricles when the ventricles are relaxed. -Ventricular relaxation.

Why is it beneficial that the heart cannot produce a sustained contraction?

-Twitches do not sum up as in skeletal muscle; therefore, the heart cannot produce a sustained contraction. -This is ultimately beneficial because if the heart became locked up, it couldn't pump blood.

From where does the superior vena cavae collect blood? the inferior vena cava?

-the superior vena cava (connects to the superior right atrium)(Carries deoxygenated blood from the upper body.) -and the inferior vena cava (connects to the inferior right atrium and carries deoxygenated blood from the lower body.)

What does it mean to say that cardiac muscle tissue is autorhythmic?

-the tissue contracts without neural stimulation.

What are the three major parts of the aorta called?

1.) Ascending Aorta 2.) Aortic Arch 3.) Descending Aorta

What are the two major branches of the left coronary artery? Where is each located?

1.) Circumflex branch of the LCA. -Supplies blood to the left atrium and posterior ventricle. 2.) Anterior interventricular (descending branch of the LCA) -Supplies blood to both ventricles.

What is the cardiac skeleton composed of, and what are some of its functions?

1.) Consists of Dense bands of tough elastic tissue that encircle the heart valves as well as the bases of the aorta and pulmonary trunk. 2.)These bands stabilize the heart valves and the bases of the great vessels. 3.) They also electrically insulate the cardiac cell of the ventricles from those of the atria. (This is important because you want the atria to contract at the same time.)

What type of tissues make up both the epicardium and the parietal pericardium? What about the endocardium?

1.) Epicardium: Consists of an outer layer of simple squamous EPI over an inner layer of areolar CT that clings to the myocardium 2.) Parietal Pericardium: - Consists of dense irregular and areolar CT with an inner lining of simple squamous EPI. 3.) Endocardium: -a simple squamous EPI that is continuous with the inner lining of the large blood vessels that attach to the heart (e.g, aorta.)

List and describe the three layers of the heart wall.

1.) Epidcardium(Same as the visceral pericardium): The outermost layer of the heart wall. 2.) Myocardium: The muscular wall of the heart. -forms both atria and ventricles. -composed of cardiac muscle tissue, blood vessels and nerves. -consists of concentric (Nesting) layers of muscle tissue. -The "Middle" of the heart. 3.) Endocardium: The inner most layer of the heart wall.

Describe the flow of blood among the coronary sinus, the cardiac veins, and the heart.

1.) Great Cardiac Vein: -Drains blood from the anterior of the heart. 2.) Middle Cardiac vein -Drains blood from the posterior heart. 3.) Coronary Sinus: -All cardiac veins empty into the coronary sinus which, in turn, empties into the right atrium.

What are three of the major cardiac veins? Where is each located?

1.) Great cardiac vein. -Runs alongside the anterior interventricular branch of the LCA. 2.) Middle Cardiac vein (aka. Posterior interventri. Vein.) -Runs alongside the posterior interventricular branch of the RCA. 3.) Coronary Sinus -it is a large, thin-walled vein on the posterior of the heart.

What's the difference between the parietal and visceral pericardium? What is the other name for the visceral pericardium?

1.) Parietal Pericardium- The outer layer - (Consists of dense irregular and areolar CT with an inner lining of simple squamous EPI.) 2.) Visceral peridcardium (aka. epicardium) - the inner layer that clings to the heart.)

What are some of the functions of the connective tissues of the heart?

1.) Physically support the muscle cells, nerve cells, and blood vessels of the heart. 2.) Prevent overexpansion of the heart. 3.) Help heart "Spring" back into its original size after contracting. 4.) Help distribute the force of contraction --so that one area doesn't suffer most of the wear and tear.

List the four valves of the heart, including any alternate names.

1.) Right Atrioventricular valve (Tricuspid Valve.) 2.) Pulmonary semilunar valve. 3.) Left Atrioventricular valve (Bicuspid Valve.)(or Mitral valve) 4.) Aortic Semilunar Valve.

List the four chambers of the heart.

1.) Right Atrium - Receives O2 poor blood from the body and passes it to the... [atrium = entry chamber] 2.) Right Ventricle - Pumps blood to the lungs. 3.) Left Atrium- Receives oxygen-rich blood from the pulmonary circuit and passes it to the... 4.) Left Ventricle - Pumps blood into systemic circuit.

Describe the path of blood through the heart and the great vessels beginning with the vena cava and ending with the descending aorta.

1.) Right atrium a.)Receives blood from the systemic circuit through two great veins: 2.) Right Ventricle 1.) Blood flows from the right atrium through the right atrioventricular (AV) valve into the right ventricle. (or called tricuspid valve.) 3.) Pulmonary Circuit A.) When the right ventricle contracts, it pumps blood through the pulmonary semilunar valve to enter the pulmonary trunk, which starts the pulmonary circuit. 4.)Left Antrium: A.) the right and left pulmonary veins deliver blood to the left atrium. 5.) Left ventricles -Blood flows from left atrium through the left atrioventricular (AV) valve into the left atrium. 6.)Aorta A.) blood is pumped by the strong left ventricle through Aortic Semilunar into the ascending aorta. So basically: Right atrium, right ventricle, pulmonary circuit, left atrium, left ventricles,and the aorta.

What's the difference between the pulmonary and systemic circuit?

1.) The pulmonary Circuit: -Carries blood to and from the lungs 2.) Systemic Circuit: -Transport blood to and from the rest of the body

What are the two major branches of the right coronary artery? Where is each located?

1.)Posterior Interventricular branch (descending) branch of the RCA(right coronary artery) -Supplies blood to both posterior ventricles. 2.) Right coronary Artery

When someone has either a heart attack or angina pectoris, where on the body do they typically feel the most intense pain?

The Chest.

To where do the right and left pulmonary veins deliver blood? The right and left pulmonary arteries?

The right and left pulmonary veins deliver blood to the left atrium. While the right and left pulmonary arteries deliver blood to the lungs to oxygenate it.

What is meant by the mediastinum?

The space between the lungs where the heart lies.

What is the thin wall between the right and left atria called? How about the thick wall between the right and left ventricles?

The thin wall between the right and left atria is the Interatrial spetum. The thick wall between the right and left ventricles is the interventricular spetum.

What are the major differences between veins, arteries, and capillaries?

Veins: -RETURN blood to the heart. Arteries: -Carry blood AWAY from the heart. (Even if un-oxygenated, e.g. pulmonary arteries which carry O2 poor blood to the lungs.) Capillaries: -Thin-walled, microscopic vessels that connect the smallest arteries to the smallest veins.

In what sense does the left ventricle help the right ventricle do its job?

When the left ventricle contracts, it bulges into the right ventricular cavity. This helps the right ventricle do its job.

What is the technical term for "heart attack"?

myocardial infarction