cardiac cycle

What does the cardiac cycle refer to?

A complete heartbeat from its generation to the beginning of the next beat.

What is heart rate?

The frequency of the cardiac cycle measured in beats per minute (bpm).

What phase of the cardiac cycle is known as systole?

The emptying phase of the cardiac cycle, characterized by contraction and increased pressure.

What occurs during diastole?

The filling phase of the cardiac cycle marked by relaxation and decreased pressure.

What is the role of the Medulla Oblongata in heart rate regulation?

It autonomously controls heart rate; increasing heart rate through sympathetic stimulation and decreasing through parasympathetic stimulation.

What hormones does the adrenal gland release that affect heart rate?

Adrenaline (epinephrine) and norepinephrine, which enhance heart rate and contraction during stress or physical activity.

What is ventricular systole?

The phase of the cardiac cycle where blood pressure in major arteries increases.

What is measured in a blood pressure reading?

Systolic pressure (higher number) and diastolic pressure (lower number).

What does the sinoatrial (SA) node do?

Acts as the pacemaker of the heart, coordinating contractions and generating nerve impulses that cause both atria to contract.

What is the function of the Atrioventricular (AV) node?

Receives electrical impulses from the SA node and slows them down to allow atria to contract and empty.

What characterizes myocardial infarction (MI)?

A heart attack where the heart begins to die due to insufficient blood flow.

What are arrhythmias?

Any problems in the rate or rhythm of blood flow.

How does tachycardia differ from bradycardia?

Tachycardia is a heart rate above 100 bpm, while bradycardia is below 60 bpm.

What is the purpose of the electrocardiogram (ECG or EKG)?

A test that traces the electrical activity of the heart to detect underlying rate and rhythm mechanisms.

What does the P wave in an ECG represent?

Atrial contraction or atrial depolarization.

What is the composition of blood?

A connective tissue consisting of living cells suspended in a nonliving extracellular matrix (plasma).

What are the formed elements of blood?

Red blood cells (RBCs), white blood cells (WBCs), and platelets.

What defines the function of platelets in the blood?

Preventing blood loss through platelet plugs and clotting.

What does hematopoiesis refer to?

The process of blood cell production in red bone marrow.

What determines blood types?

Antigens on the surface of red blood cells, with corresponding antibodies in the plasma.

What are arteries primarily responsible for?

Carrying blood away from the heart with thick walls and high blood pressure.

What does systemic circulation encompass?

Blood flow from the left ventricle to all parts of the body and back to the right atrium.

How does blood pressure change during the cardiac cycle?

It increases during ventricular systole and decreases during ventricular diastole.

What is hypotension and what are some causes?

Low blood pressure (below 90/60) caused by dilation of arteries, dehydration, or blood loss.

What is hypertension and some of its causes?

High blood pressure caused by constriction of arterioles, excessive salt intake, obesity, or smoking.

Describe anemia.

A condition characterized by low hemoglobin and iron deficiency that leads to decreased oxygen availability to cells.

What is deep vein thrombosis?

The formation or presence of a blood clot (thrombus) within a blood vessel, often in the legs.