Circulatory System 3 term 1

During systole, the ventricles are in a state of relaxation and filling.

The cardiac cycle is triggered by the spread of excitation through the arteries.

The cardiac cycle consists of only one phase.

The first heart sound is caused by the closure of aortic and pulmonary valves at the start of ventricular contraction.

Arteries carry blood from organs and tissues back to the heart.

Muscular arteries, such as the aorta and pulmonary artery, have numerous layers of elastin fibers in their vessel walls.

The tunica externa of blood vessels is the innermost lining of squamous endothelium.

Capillaries facilitate exchanges between blood and surrounding cells within organs.

The venules return blood to the heart after forming when capillaries re-join.

The elastic arteries expand when pressure of the blood decreases during ventricular systole.

Arterioles contain the highest percentage of smooth muscle in the vessel wall.

Capillaries have very thin walls consisting of a single layer of flat endothelial cells and a thin basement membrane.

Capillaries in the kidneys, intestines, and endocrine glands have larger holes in addition to narrow pores, providing greater permeability and rapid exchange.

Bulk flow is a mechanism of capillary exchange involving ultrafiltration and reabsorption of protein-free plasma.

Systemic veins have thin walls with little smooth muscle or elastin, resulting in high distensibility and little elastic recoil.

The main function of precapillary sphincters is to regulate blood flow via venules.

Arteries have a thicker layer of smooth muscle but are more elastic than arterioles.

Vessel radius supplying individual organs cannot be adjusted independently depending on the body’s momentary needs.

Continuous capillaries have larger holes (20-100 nm) in addition to narrow pores.

Bulk flow as a mechanism of capillary exchange involves diffusion down the concentration gradient.

The refractory period occurs for some time after a previously elicited action potential.

The duration of the refractory period differs for fast and slow response cells.

The natural pattern of excitation of the heart starts with the SA node, then goes to the ventricles before reaching the AV node.

The ECG records the electrical activity of the heart during repolarization only.

Cardiac muscle cells are interconnected to form branching fibers through specialized structures known as desmosomes.

Cardiac muscle cells become excited and contract individually rather than as a single unit.

Gap junctions in cardiac muscle fibers allow cell-to-cell communication.

The T wave in an ECG represents atrial depolarization.

Automaticity refers to the ability of all cardiac cells to initiate action potentials spontaneously.

The refractoriness protects against premature excitation and tetany.

The electrical activity of the heart is cyclically initiated and conducted in a disorderly sequence through the heart by autorhythmic cells.

Intercalated discs in cardiac muscle contain desmosomes for cell-to-cell communication.

During which phase of the cardiac cycle do the ventricles relax and fill?

What is the main function of elastic arteries?

Which type of blood vessel serves as rapid-transit conduits for blood from the heart to organs?

What is the term for the closure of AV valves at the start of ventricular contraction?

What do venules do with blood after forming when capillaries re-join?

What is the main function of muscular arteries?

Which layer of blood vessel walls is comprised of smooth muscle?

What happens to elastic arteries when the pressure of the blood rises during ventricular systole?

What is the innermost lining of squamous endothelium in blood vessels called?

What happens during isovolumetric relaxation?

What occurs during the ejection period?

What is the primary purpose of the refractory period in cardiac cells?

Which structure is responsible for the natural initiation of excitation of the heart?

What does the T wave in an ECG represent?

What is the main function of precapillary sphincters?

Which mechanism is involved in capillary exchange involving ultrafiltration and reabsorption of protein-free plasma?

What is the primary role of gap junctions in cardiac muscle fibers?

Which part of the heart is responsible for the spread of action potentials across muscle cell membranes?

What is the characteristic feature of automatic/pacemaker cells in the heart?

What role does AV conduction delay play in the heart?

What is indicated by the QRS complex in an ECG?

What is the function of desmosomes in cardiac muscle fibers?

What is the major function of precapillary sphincters in capillaries?

What is the main determinant of bulk flow in capillaries?

What is the function of systemic veins in the circulatory system?

What is the structure of continuous capillaries?

What is the primary characteristic of arterioles in terms of their function?

What is the primary function of capillaries within organs?

Which vessel type has a thicker layer of smooth muscle but less elasticity?

What is the primary role of veins in the circulatory system?

What is the primary factor that facilitates venous return in the circulatory system?

What is the main function of arterioles in the circulatory system?

Which vessel type plays a significant role in controlling arterial blood pressure?

Which type of blood vessel contains the highest percentage of smooth muscle in the vessel wall?

What is the primary function of precapillary sphincters?

What is the main determinant of bulk flow in capillaries?

Which type of capillaries has larger holes in addition to narrow pores, providing greater permeability and rapid exchange?

What occurs during isovolumetric relaxation?

What is the structure of continuous capillaries?

What role does AV conduction delay play in the heart?

What is the main function of muscular arteries?

During which phase of the cardiac cycle do the ventricles relax and fill?

What is the primary factor that facilitates venous return in the circulatory system?

What part of the cardiac cycle indicates closure of AV valves at the start of ventricular contraction?

What is indicated by the QRS complex in an ECG?

What is the primary purpose of the refractory period in cardiac cells?

Which structure is responsible for the natural initiation of excitation of the heart?

What is the characteristic feature of automatic/pacemaker cells in the heart?

What role does AV conduction delay play in the heart?

Which part of the heart is responsible for the spread of action potentials across muscle cell membranes?

What occurs during the ejection period?

What do venules do with blood after forming when capillaries re-join?

What is the main function of arterioles in the circulatory system?

What is the primary function of precapillary sphincters in capillaries?

Which phase of the cardiac cycle is characterized by ventricular contraction and emptying?

What is the term for the two sub-phases or periods during diastole?

Which type of arteries serve as rapid-transit conduits for blood from the heart to organs, and act as pressure reservoirs?

What type of vessels are formed when capillaries re-join to return blood to the heart?

What is the middle layer of the arterial walls composed of?

What is the main function of capillaries within organs?

What is the outer layer of arterial walls comprised of?

During which phase of the cardiac cycle do the ventricles relax and fill?

'Consists of Arteries – carry blood away from heart to tissues' - this statement refers to which component of the circulatory system?

What type of vessels direct the flow of blood from the heart to organs & tissues and back to the heart?

Which layer of blood vessel walls is composed of up to 3 'tunics' including tunica externa, tunica media, and tunica interna?

What are the two sub-phases or periods of systole?

What is the function of arterioles in the circulatory system?

What is the primary characteristic of arterioles in terms of their function?

What is the main determinant of bulk flow in capillaries?

What is the primary function of muscular arteries?

What is the structure of continuous capillaries?

What is the middle layer of the arterial walls composed of?

What happens to elastic arteries when the pressure of the blood rises during ventricular systole?

What type of vessels are formed when capillaries re-join to return blood to the heart?

What is the main function of systemic veins in the circulatory system?

What is the primary factor that facilitates venous return in the circulatory system?

What is the function of precapillary sphincters in capillaries?

What is the role of precapillary sphincters in the circulatory system?

What are the three main types of capillaries based on the size of water-filled pores?

What are the two mechanisms of capillary exchange between blood and surrounding tissues?

What is the primary function of venules in the circulatory system?

What are the determinants of bulk flow in capillaries?

What is the primary role of systemic veins in the circulatory system?

How is the control of the tone (constriction or dilatation) of arterioles mediated?

What is the main role of arterioles in the circulatory system?

What are the two sub-phases or periods during diastole?

How do continuous capillaries differ from fenestrated capillaries?

What is the characteristic feature of veins in terms of their structure?

How do arterioles contribute to controlling arterial blood pressure?

What is refractoriness in cardiac cells?

What is the primary basis of automaticity in cardiac cells?

What is the sequence of electrical conduction through the heart during the natural pattern of excitation?

What are the three distinct waveforms in a normal ECG and their corresponding representations?

What is the primary function of gap junctions in cardiac muscle fibers?

What differentiates the refractory period in fast response cells from slow response cells?

What is the primary function of the Electrocardiogram (ECG or EKG)?

What is the primary role of the AV conduction delay in the heart?

What is the structural basis for the functional syncytium of cardiac muscle?

What are the two types of membrane junctions present within an intercalated disc in cardiac muscle?

What is the primary characteristic of normal cardiac automatic or pacemaker cells?

What is the primary characteristic feature of cardiac cells during the refractory period?