Human Biology: Cardiovascular System (Chapter 5)

This flashcard set covers the vocabulary and key concepts from Chapter 5 on the Cardiovascular System, including blood vessel types, heart anatomy, the cardiac cycle, blood pressure and circulation pathways, and common cardiovascular disorders.

Cardiovascular system

A biological system made up of the heart and blood vessels responsible for pumping blood and bringing nutrients to cells while removing wastes.

Interstitial fluid

The fluid through which the exchange of substances between blood and cells occurs.

Lymphatic system

A system that assists the cardiovascular system by collecting excess interstitial fluid and returning it to the blood.

Lymph

The name for fluid once it has entered the lymphatic vessels.

Artery

A blood vessel that carries blood away from the heart; its walls consist of an inner endothelium, a middle layer of smooth muscle and elastic tissue, and an outer layer of connective tissue.

Endothelium

The thin, inner epithelium that forms the innermost layer of blood vessels.

Arterioles

Small arteries whose middle layer is mostly smooth muscle; they contract or dilate to regulate blood flow and pressure.

Capillaries

Microscopic vessels between arterioles and venules where gas, nutrient, and waste exchange occurs across walls made only of endothelium.

Precapillary sphincters

Structures that control blood flow through a capillary bed; when closed, blood flows through an arteriovenous shunt.

Venules

Small veins that receive blood from the capillaries.

Veins

Blood vessels that carry blood toward the heart, often containing valves to prevent backward flow and storing approximately $70\%$ of the blood at any one time.

Myocardium

The cardiac muscle tissue that makes up the majority of the heart.

Intercalated disks

Structures connecting cardiac muscle fibers that contain gap junctions for unison contraction and desmosomes to prevent overstretching.

Pericardium

The sac surrounding the heart that secretes pericardial fluid for lubrication.

Septum

The internal wall that divides the heart into right and left sides.

Atria

The two upper chambers of the heart (singular: atrium).

Ventricles

The two lower chambers of the heart.

Atrioventricular (AV) valves

Valves reinforced by chordae tendineae located between the atria and ventricles, including the bicuspid (mitral) and tricuspid valves.

Semilunar valves

The pulmonary and aortic valves located between the ventricles and their respective major arteries.

Coronary arteries

The first branches off the aorta that supply the myocardium with its own blood supply.

Aorta

The largest artery in the systemic circuit through which the left ventricle pumps oxygen-rich blood to the body.

Systole

The phase of the cardiac cycle representing heart contraction.

Diastole

The phase of the cardiac cycle representing heart relaxation.

SA (sinoatrial) node

The pacemaker of the heart located in the right atrium that initiates the heartbeat with electrical signals.

AV (atrioventricular) node

A node in the right atrium that receives the impulse from the SA node and sends it through the AV bundle and Purkinje fibers to cause ventricular contraction.

Electrocardiogram (ECG)

A recording of the electrical changes in the heart muscle during a cardiac cycle, consisting of a P wave, QRS complex, and T wave.

Pulse

The surge of blood into an artery that causes walls to stretch and recoil, representing the heart rate which averages $60-80$ beats per minute.

Sphygmomanometer

The instrument used to measure blood pressure, usually in the brachial artery of the arm.

Systolic pressure

The highest blood pressure reached when blood is ejected from the heart during ventricular contraction.

Diastolic pressure

The lowest blood pressure reached when the ventricles relax.

Hypertension

High blood pressure, clinically defined as a systolic pressure of $140$ or higher or a diastolic pressure of $90$ or higher.

Skeletal muscle pump

A mechanism that assists venous return to the heart through the contraction of skeletal muscles.

Pulmonary circuit

The pathway that circulates deoxygenated blood through the lungs for gas exchange.

Systemic circuit

The pathway that circulates oxygenated blood through the body tissues.

Hepatic portal vein

A specialized vein that brings nutrient-rich blood from the digestive tract directly to the liver for filtration and processing.

Atherosclerosis

A cardiovascular disorder characterized by the buildup of plaque in the walls of blood vessels.

Thromboembolism

An embolus (a detached, moving clot) that has become lodged in a blood vessel.

Myocardial infarction (MI)

Commonly known as a heart attack, it occurs when part of the heart dies due to oxygen lack from a blocked coronary artery.

Aneurysm

A ballooning of a blood vessel wall, often caused by atherosclerosis and hypertension.

Angioplasty

A medical procedure where a tube and stent are inserted into a clogged artery to hold it open.