Structure and Function of the Human Body: Cardiovascular System (Part A: The Heart)

These flashcards cover key concepts related to the structure and function of the heart as part of the cardiovascular system, including anatomy, blood flow, the cardiac cycle, and control mechanisms.

What is the primary function of the heart?

The heart pumps blood throughout the body.

Where is the heart located?

Between the lungs, directly behind the sternum.

Which structure is responsible for allowing cardiac muscle cells to contract in unison?

Intercalated disks.

What are the two types of valves in the heart that prevent backflow of blood?

Atrioventricular (AV) valves and semilunar valves.

What is the left AV valve called?

Bicuspid or mitral valve.

What is the right AV valve known as?

Tricuspid valve.

What condition occurs if there is blockage in the coronary arteries?

Coronary artery disease, which can lead to a myocardial infarction (heart attack).

What do coronary arteries supply to the myocardium?

Oxygen and nutrients.

Where do coronary veins drain into?

The right atrium.

What type of blood do the inferior and superior vena cava carry?

Oxygen-poor, carbon dioxide-rich blood.

What part of the heart does blood enter from the systemic veins?

The right atrium.

What is the function of the pulmonary veins?

They carry oxygen-rich, carbon dioxide-poor blood from the lungs to the left atrium.

What is the septum's role in the heart?

It separates the heart into two sides, preventing mixing of oxygen-rich and oxygen-poor blood.

What is the difference between the walls of the atria and ventricles?

Atria have thinner walls than ventricles.

What happens during the systole phase of the cardiac cycle?

The heart contracts.

What phase follows systole in the cardiac cycle?

Diastole, where the heart relaxes.

How frequently does the heart beat on average in a healthy adult?

About 70 times per minute.

What causes the 'lub' sound during a heartbeat?

Closure of the AV valves.

What causes the 'dub' sound during a heartbeat?

Closure of the semilunar valves.

What is the purpose of the SA node?

It acts as the pacemaker, initiating the heartbeat.

What does the AV node do?

It sends out electrical signals to contract the ventricles.

What does an electrocardiogram (ECG) measure?

The electrical activity of the heart.

What does the P wave in an ECG signify?

The depolarization of the atria before contraction.

What does the QRS complex represent?

The depolarization of the ventricles.

What is the T wave indicative of in an ECG?

The recovery of the ventricles after contraction.

What medical emergency is indicated by uncoordinated electrical signals in the ventricles?

Ventricular fibrillation.

What is the effect of sympathetic stimulation on heart rate?

It increases heart rate.

What is the role of hormones like epinephrine in the heart?

They stimulate the heart to increase its rate and force of contraction.

What happens when the heart is under stress?

Heart rate increases due to increased activity of the SA and AV nodes.

Where are the coronary arteries located?

On the exterior surface of the heart.

What do the valves of the heart prevent?

Backflow of blood.

What must happen for blood to pass from the right side of the heart to the left side?

It must go through the lungs.

Why does the left ventricle have thicker walls than the right ventricle?

It pumps blood throughout the entire body, requiring more force.

What is the primary role of the myocardial tissue in the heart?

It enables the heart to contract and pump blood.

How does blood pressure change as it moves through arteries?

Blood pressure decreases as it moves into smaller arteries and arterioles.

What is the significance of desmosomes in cardiac tissue?

They help hold the membrane of adjacent cardiac cells together and prevent overstretching.

What happens when there is an irregular ECG trace?

It may indicate a heart condition such as ventricular fibrillation.

How does the cardiac control center in the brain influence the heart rate?

It can increase or decrease heart rate based on the body's needs.

What is the function of Purkinje fibers?

They conduct electrical signals that stimulate ventricular contraction.