Gross Anatomy of The Heart Quiz

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Questions and Answers

Where is the heart located?

Around the hips

Above the diaphragm

Between the second rib to the fifth (correct)

Behind the lungs

Which direction does the base of the heart point towards?

Left shoulder

Neck

Right shoulder (correct)

Left hip

What is the mass of the heart approximately?

~ 500 grams

~ 1000 grams

~ 300 grams (correct)

~ 750 grams

Which layer of the heart wall is also known as the visceral pericardium?

Epicardium Signup and view all the answers

In which cavity is the heart enclosed within a double-walled sac?

Pericardial cavity Signup and view all the answers

Where does the apex of the heart point towards?

Hip Signup and view all the answers

What is the main component of the Myocardium?

Cardiac muscle Signup and view all the answers

What structures allow ions to flow from cell to cell in the cardiac muscle?

Gap junctions Signup and view all the answers

Which chambers of the heart are primarily receiving chambers and not important in the pumping activity of the heart?

Atria Signup and view all the answers

Why are the walls of the left ventricle substantially thicker than those of the right ventricle?

It pumps blood over a longer pathway Signup and view all the answers

Which vessel splits into right and left pulmonary arteries?

Pulmonary trunk Signup and view all the answers

Which vessels return blood to the heart from regions above and below the diaphragm?

Venae cavae Signup and view all the answers

What is the role of the semilunar valves during ventricles relaxation?

Forced closed Signup and view all the answers

What causes the AV valves to open?

High blood pressure in the ventricles Signup and view all the answers

What happens to the AV valves when the ventricles contract?

They hang limply Signup and view all the answers

What prevents semilunar valve flaps from everting into the atria?

Atrial contraction Signup and view all the answers

When do the semilunar valves close?

During ventricular relaxation Signup and view all the answers

What forces open the semilunar valves?

Intraventricular pressure rise Signup and view all the answers

What is the function of intercalated discs in cardiac muscle tissue?

To conduct muscle action potentials Signup and view all the answers

Which protein complex is found on the thin filament in cardiac muscle cells?

Troponin Signup and view all the answers

What is the role of transverse tubules in cardiac muscle cells?

Allow muscle action potentials to conduct Signup and view all the answers

What holds cardiac muscle fibers together at their ends?

Desmosomes Signup and view all the answers

Where are the Z discs located in cardiac muscle fibers?

At the center of the fibers Signup and view all the answers

What is the function of gap junctions in cardiac muscle tissue?

To allow communication between muscle fibers Signup and view all the answers

What happens during the ventricular filling phase in the cardiac cycle?

Atrial contraction forces blood into the ventricles Signup and view all the answers

What is the volume of blood in the ventricles at the end of atrial contraction?

130 ml Signup and view all the answers

What characterizes the ventricular systole phase in the cardiac cycle?

The AV valves close to prevent backflow Signup and view all the answers

What occurs during the isovolumetric contraction phase of ventricular systole?

Ventricles are closed chambers with increasing pressure Signup and view all the answers

How does atrial contraction affect the volume of blood in the ventricles?

Increases it by 25 ml Signup and view all the answers

What leads to the closing of the AV valves in the cardiac cycle?

Increase in ventricular pressure Signup and view all the answers

Study Notes

Heart Location and Structure

The heart is located in the mediastinum, a region in the chest between the lungs.
The base of the heart points towards the right shoulder, while the apex points towards the left hip.
The heart's mass is approximately 250-350 grams in adults.
The epicardium, also known as the visceral pericardium, is the outermost layer of the heart wall.
The heart is enclosed within a double-walled sac called the pericardium, located within the thoracic cavity.

Cardiac Muscle Tissue

The myocardium, the middle layer of the heart wall, mainly comprises cardiac muscle tissue.
Intercalated discs, specialized junctions between cardiac muscle cells, allow ions to flow freely, enabling synchronized contractions.
Gap junctions within intercalated discs facilitate the rapid spread of electrical impulses throughout the heart.

Heart Chambers and Valves

The atria (right and left) are the receiving chambers of the heart, collecting blood returning from the body.
The ventricles (right and left) are the pumping chambers, propelling blood to the lungs and the rest of the body.
The left ventricle has thicker walls than the right ventricle to pump blood with greater force against higher resistance.
The pulmonary trunk splits into the right and left pulmonary arteries, carrying deoxygenated blood to the lungs.
The superior and inferior vena cava return deoxygenated blood to the right atrium from regions above and below the diaphragm, respectively.
Semilunar valves prevent backflow of blood from the ventricles into the great arteries during ventricular relaxation.
AV valves (tricuspid and bicuspid) open when ventricular pressure is lower than atrial pressure.
When the ventricles contract, the AV valves close to prevent backflow of blood into the atria.
Chordae tendineae anchor the AV valve flaps to papillary muscles, preventing them from everting into the atria.
The semilunar valves close when ventricular pressure drops below arterial pressure during relaxation.
The semilunar valves open when ventricular pressure exceeds arterial pressure.

Muscle Structure and Function

Intercalated discs in cardiac muscle tissue facilitate communication and synchronous contractions, ensuring coordinated heartbeat.
The troponin-tropomyosin complex is present on the thin filaments of cardiac muscle cells, regulating muscle contraction.
Transverse tubules (T-tubules) in cardiac muscle cells help transmit action potentials, ensuring uniform contraction of the muscle fibers.
Desmosomes, specialized junctions, hold cardiac muscle fibers together at their ends, providing structural integrity.
Z discs, anchoring points for the thin filaments, are located at the ends of sarcomeres in cardiac muscle fibers.

Cardiac Cycle

During ventricular filling, blood passively flows from the atria into the ventricles, followed by forceful atrial contraction to complete the filling
End-diastolic volume (EDV) is the volume of blood in the ventricles at the end of atrial contraction.
Ventricular systole is the period of ventricular contraction, marked by increased pressure within the ventricles.
Isovolumetric contraction occurs at the beginning of ventricular systole when both AV and semilunar valves are closed, allowing for a brief increase in ventricular pressure without changing volume.
Atrial contraction adds about 20% to the blood volume in the ventricles.
Increased ventricular pressure leads to the closing of the AV valves.

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Description

Test your knowledge on the gross anatomy of the heart, including details on shape, size, mass, and location within the human body. Explore the key characteristics of the heart's position in relation to other organs.