Heart

What are the basic functions of the circulatory system?

The circulatory system's main functions are to transport substances like oxygen, nutrients, and waste throughout the body, help regulate temperature and pH, support the immune system, and maintain fluid balance.

Where is the heart located within the chest?

The heart is located in the chest slightly left of center behind the sternum.

What is the pericardium?

The pericardium is a protective sac around the heart.

The walls of the heart contain myocardium and endocardium. What is the specific function of these layers of the heart wall?

The heart walls consist of the myocardium (muscular layer) responsible for the heart's pumping action and endocardium (lining) of the heart chambers and valves, providing a smooth surface for blood flow.

How are the atria different from the ventricles in terms of their size, location, and function?

Atria are smaller, upper chambers that receive blood; ventricles are larger, lower chambers that pump blood out.

How is pulmonary circulation different from systemic circulation? Which side of the heart drives the two different circulations?

Pulmonary circulation carries blood to the lungs for oxygenation, while systemic circulation delivers oxygenated blood to the body. The right side of the heart drives pulmonary circulation; the left side drives systemic circulation.

What path does the blood follow through the heart and lungs starting with the right atrium?

Blood flows from the right atrium to the right ventricle, then to the lungs for oxygenation, returning to the left atrium, then to the left ventricle, and finally to the body.

How many valves are in the heart?

Four - tricuspid valve, pulmonary valve, mitral valve (bicuspid), and aortic valve.

What is the function of the AV valves? When are they open and closed?

AV valves (tricuspid and mitral) prevent backflow of blood into the atria during ventricular contraction. They are open during heart relaxation (diastole) and closed during ventricular contraction (systole).

What is the function of the semilunar valves? When are they open and closed?

Semilunar valves (pulmonary and aortic) prevent blood from flowing back into the ventricles after contraction. They are closed during diastole and open during ventricular contraction (systole).

How are cardiac muscle cells different from skeletal muscle cells?

Cardiac muscle cells have automaticity and conductivity, allowing them to contract without nerve stimulation.

Two systems act to regulate heart activity?

The autonomic nervous system and the endocrine system regulate heart activity.

Function of the sinoatrial (SA) node in heart function? Where is it located?

The SA node initiates the heartbeat and is located in the right atrium.

Function of the atrioventricular (AV) node in heart function? Where is it located?

The AV node delays the electrical impulse to allow atria to contract before ventricles and is located in the lower part of the right atrium.

Function of the atrioventricular (AV) bundle in heart function? Where is it located?

The AV bundle conducts the impulse from the AV node to the ventricles and is located in the interventricular septum.

Function of the Purkinje fibers in heart function? Where are they located?

Purkinje fibers distribute the impulse throughout the ventricles and are located in the walls of the ventricles.

How is systole different from diastole?

Systole is the contraction phase, diastole is the relaxation phase.

Cardiac output measure?

Cardiac output measures the volume of blood pumped by the heart per minute.

Factors that contribute to cardiac output?

Heart rate and stroke volume.

Factors that can increase cardiac output?

Exercise, sympathetic stimulation, and certain hormones (e.g., epinephrine) can increase cardiac output.

Factors that can decrease cardiac output?

Factors like dehydration, heart disease, and certain medications can decrease cardiac output.

Five types of vessels the blood travels in throughout the body?

Blood travels through arteries, arterioles, capillaries, venules, and veins.

Arteries similar to veins?

Arteries and veins both transport blood around the body.

Arteries different from veins?

Arteries carry oxygenated blood away from the heart, veins carry deoxygenated blood back to the heart.

Physiology of Circulation

Vital signs

temperature, pulse rate, respiration rate, and blood pressure.

Blood pressure?

the force exerted by blood against the walls of blood vessels.

How is the systolic pressure different from the diastolic pressure?

Systolic pressure is the pressure during ventricular contraction. Diastolic pressure is the pressure during ventricular relaxation.

How do vasoconstriction and vasodilation help regulate blood pressure?

Vasoconstriction narrows blood vessels, increasing blood pressure. Vasodilation widens blood vessels, decreasing blood pressure.

Factors that can increase blood pressure?

Factors like stress, obesity, and high salt intake can increase blood pressure.

Factors that can decrease blood pressure?

Factors like dehydration, bleeding, and shock can decrease blood pressure.

myocardial infarction

Death of heart muscle due to blocked blood flow.

Fibrillation

Abnormal heart rhythm causing rapid, irregular contractions.

Tachycardia

Abnormally fast heart rate.

Bradycardia

Abnormally slow heart rate.

Hypertension

High blood pressure.

Hypotension

Low blood pressure.

orthostatic hypotension

Sudden drop in blood pressure upon standing.

circulatory shock

Inadequate blood flow to meet the body's needs.