Cardiovascular System: HEART AND CIRCUITS

NO IMAGES JUST STRUCTURE AND FUNCTION

What cavity in the body contains the heart? 

ventral body cavity 

what is the subdivision in the ventral body cavity that contains the heart?

thoracic cavity

The heart is located in what region of the thoracic cavity and is surrounded by what cavity?

mediastinum, pericardial cavity

What is the space between the visceral and parietal layers of the serous membrane (component of the pericardial sac or the pericardium)?

pericardial cavity 

Which of the following lists correctly identifies all four types of major great vessels directly connected to the chambers of the heart

aorta, pulmonary trunk, pulmonary veins, superior venae cavae and inferior venae cavae 

The fibrous portion of the pericardium anchors the heart by fusion to which two primary structures?

The diaphragm and inside of the sternum

Which statement accurately describes the anatomical orientation and position of the human heart in the chest?

The base is directed toward the right shoulder, and the apex points towards the left hip, with the right atrium and ventricle forming the anterior surface

The anterior (sternocostal) surface of the heart is formed primarily by the Right Atrium and Right Ventricle. What is the most significant functional implication of this specific anatomical arrangement?

It places the lower pressure right sided chamber forward offering protection to the high pressure left ventricle that is posterior.

The heart’s apex is positioned pointing down, forward, and to the left. What is the main functional reason for this specific postioning?

It creates a specific spot ont he chest where the strongest beat can be felt and heard

The base is directed superiorly, posteriorly and to the right within the mediastinum. What is the most significant functional and structural role of this?

To provide the fixed points for the great vessels, ensuring the intimation of both systemic and pulmonary circulation

Anatomically, two-thirds of the heart’s mass lies to the left of the midsternal line. This structural features is a direct functional reflection of which requirement?

the necessity of the left ventricle having significantly greater muscle mass to generate the high pressure needed for systemic circulation

What is the primary function of fibrous pericardium (outermost layer)

prevents outstretching, provides protection, anchors the heart

What is the primary function of serous pericardium?

secretes fluid into the pericardial cavity

What are the two sub- layers of the serous pericardium

parietal layer, visceral layer (epicardium)

Which layer of the pericardium lines the inside of the fibrous pericardium

parietal layer

Which layer of the serous pericardium is adhering tightly to the surface of the heart?

visceral layer ( epicardium)

What is the function of pericardial fluid?

to reduce friction between layers of the serous pericardium as the heart moves

What is the approximate weight of an average adult heart?

300g

How is the shape of the heart commonly described?

cone-shaped or triangular

What is the pointed end of the heart called?

apex of the heart

What part of the heart is opposite of the apex?

base

The mediastinum, where the heart is situated, extends between which of the following?

form the sternum to the vertebral column, from the first rib to the diaphragm, and between the lungs

Where is the anterior interventricular sulcus located?

on the anterior surface of the heart

Where is the posterior intervenricular sulcus located?

around to the posterior surface of the heart

Where is the coronary sulcus located?

The boundary between the superior atria and inferior ventricles

Which of the following is found within coronary sulcus, anterior interventricular sulcus, and posterior interventricular sulcus?

blood vessels and fat

Which part of the heart forms the right surface?

right atrium

Which veins supply blood to the right atrium (3)

superior vena cava, inferior vena cava, and coronary sinus

How is the inside of the posterior wall of the right atrium described?

smooth

What causes the anterior wall of the right atrium to be rough?

Presence of muscular ridges called pectinate muscles

What is the thickness of the left atrium compared to the right atrium

the same thickness

What forms most of the base of the heart?

left atrium

Through which vessels does the left atrium recieve blood?

four pulmonary veins

Which part of the left atrium’s wall is smooth?

both anterior and posterior walls

Blood passes from the left atrium into the left ventricle through which structure?

left atrioventricular valve

Which surface of the heart does the right ventricle mostly form?

anterior surface

What are the ridges inside the right ventricle formed by?

trabeculae carneae

What type of tissue forms the traveculae carneae?

cardiac muscle fibers

What seperates the right ventricle from the left ventricle internally

interventricular septum

Which chamber of the heart is the thickest?

left ventricle

What part of the heart does the left ventricle form?

apex of the heart

Which structures are found in both the right and left ventricles?

Trabeculae carneae and chordae tendineae

What do the chordae tendineae in the left ventricle attach to?

papillary muscles

Through which valve does blood pass from the left ventricle into the ascending aorta?

aortic valve

Why is the wall of the left ventricle so much harder to compress inward than the wall of the right ventricle?

the left ventricle pumps blood to the entire body (systemic circulation), which required it to generate high pressure. It is therefore 3 times thicker and more muscular than the right ventricle wall which only pumps blood to the lungs (pulmonary circulation) at low pressure

The left ventricular wall is significantly thicker and less compressible than the right ventricular wall because

The left ventricle must overcome the high resistance of the systemic circulation.

Which chambers of the heart recieve blood returning from the veins

right atrium and left atrium

Compared to the ventricles, the atria have?

much less myocardial tissue in their walls

Why do the atria have less myocardial tissue than the ventricles?

Because they have a much lower workload

The function of the atria is to?

Receive blood returning to the heart from the veins

What are the two powerful pumps that eject blood into the arteries

right ventricle and left ventricle

What provides the force to pressurize the blood in the ventricles?

thick myocardium

Which part of the heart is responsible for driving blood circulation?

ventricles

What does the interventricular septum divide?

right ventricle from the left ventricle

What does the interatrial septum seperate?

right atrium from the left atrium

Which of the following correctly describes the function of the right pump

Receives deoxygenated blood and sends it to the pulmonary circuit (to the lungs)

The left pump is designed to handle which type of blood and send it to which circuit?

oxyginated blood to systematic circuit

In the heart’s double pump design, how is the blood type and circulation pathway correctly paired?

Left Pump: Oxygenated blood → Systemic Circuit

Right Pump: Deoxygenated blood → Pulmonary Circuit.

What is the purpose of the pulmonary circuit?

to transport deoxygenated blood to the lungs for gas exchange (pick up 02 and drop off CO2)

What is the purpose of the systemic circuit?

to transport oxygenated blood to the rest of the body (tissues and organs)

Why must blood return to the heart after the lungs?

to get a high pressure boost from the left ventricle for fast circulation throughout the systemic circuit

What is the primary benefit of separating oxygenated and deoxygenated blood?

To ensure body tissues receive blood with the maximum possible oxygen concentration, supporting the high metabolic rate of mammals/birds

What are the two names for the separate circuits and which side of the heart powers each one?

Pulmonary Circuit (Right Side) ➡ Lungs

Systemic Circuit (Left Side) ➡ Body.

What are the three layers of the heart wall?

epicardium, myocardium, and endocardium

What is the outermost layer of the epicardium called?

visceral layer of the serous pericardium

What type of cells compose the thin, transparent outer layer of the epicardium?

mesothelium

What tissue predominate beneath the mesothelium in the epicardium

adipose tissue

Over which part of the heart does the adipose tissue layer become tickest

ventricular surfaces

What texture does the epicardium impart to the outermost surface

smooth and slippery

What does epicardium contain?

blood vessels, lymphatics, nerves

Why is the epicardial adipose tissue important in relation to the heart vessels?

It houses the major coronary and cardiac vessels

What is the primary function of the middle myocardium?

Pumping action of the heart

The myocardium is composed mainly of which type of tissue

Cardiac muscle tissue

The muscle fibers in the middle myocardium are wrapped and bundled with connective tissue sheaths composed of:

Endomysium and perimysium

How are the cardiac muscle fibers in the myocardium organized?

In bundles that swirl diagonally around the heart

Cardiac muscle fibers are similar to skeletal muscle fibers in that they are:

Striated and wrapped in connective tissue sheaths

The connective tissue sheath called endomysium surrounds

Individual muscle fibers

What is the innermost layer of the heart called?

endocardium

What type of tissue primarily composes of endocardium

endothelium over connective tissue

What is the main function of endocardium

Providing a smooth lining for heart chambers and valves

How does the endocardium reduce friction within the heart?

Through its smooth endothelial lining

The endocardium is continuous with the endothelial lining of which structures?

The large blood vessels attached to the heart

Which layer lies directly beneath the endothelial layer of the endocardium?

connective tissue

What is the main function of the left ventricle?

to pump oxygenated blood from the heart, through the aortic valve, into the aorta, and then to the rest of the body

The structure that marks the external boundary between the ventricles on the posterior aspect of the heart is the

posterior interventricular sulcus.

Which chambers (atria or ventricles) have a thicker myocardial walls?

ventricles have the thicker walls because they pump blood under high pressure over a greater distance

What is the functional difference in the workload of the atria versus the ventricles?

Atria has low workload, which ventricles have a high workload

Why does the atria have a low workload?

it acts as recieving chambers and only need to pump blood a short distance

What does the ventricles have a high workload?

they are the main pumping chambers and must propel blood over long distances and against high resistance

How does the difference in myocardial quantity allow the difference in their workloads?

low pressure is only for a short distance, high pressure moves blood through the entire circulatory system

Where are the AV valves located

between atrium and the ventricle

What is the composition of AV valves?

it is open, and rounded ends of cusps projecting into the ventricle, they will close

WHat is the function of AV valves

when av valve is open it moves blood to high pressure in the atria to lower pressure in the ventricles (one way flow)

What is another function of AV valves with their seals and openings

closes the opening to stop backward flow

will ensure the seal holds against high pressure contraction

what are semilunar valves aka

aortic and pulmonary valve

What is the composition of semilunar valves

they are made up of 3 crescent moon shaped cusps, each will attach to an arterial wall

What is the function of the SL valve?

allow ejection of blood from the heart into arteries but prevents backflow of blood into the ventricles 

What is the function of chordae tendineae?

tendonlike, fibrous cords that connect the atrioventricular valves of the heart with the papillary muscles

What is the function of papillary muscles

prevents the atrioventricular valves from flapping back into the atria during ventricular contractions by pulling on the chordae tendineae

What is the function of pectinate muscles?

muscle bundles of the Anterior atrial walls and the lining of auricles for surface area and contractility