Circulatory System

Endocardium

Smooth inner lining of the heart; serous membrane (endo- within, cardi- heart, -um membrane)

Myocardium

Muscular middle layer of the heart (myo- muscle)

Pericardium

Double-layered sac around the heart; contains fluid to reduce friction (peri- around)

Right Atrium

Receives deoxygenated blood from body (via vena cava)

Right Ventricle

Pumps blood from right atrium into pulmonary artery → lungs

Left Atrium

Receives oxygenated blood from lungs

Left Ventricle

Pumps blood into aorta → to body

Tricuspid Valve

Valve between right atrium & right ventricle

Pulmonary Valve

Valve between right ventricle & pulmonary artery

Mitral Valve

Valve between left atrium & left ventricle

Aortic Valve

Valve between left ventricle & aorta

Septum

Muscular wall dividing right & left sides of the heart

Interatrial Septum

Upper dividing wall between atria

Interventricular Septum

Lower dividing wall between ventricles

Atria

Upper chambers of the heart

Ventricles

Lower chambers of the heart

Diastole

Relaxation of the heart

Systole

Contraction of the heart

SA Node (Pacemaker)

Starts electrical impulse in right atrium

AV Node

Delays & transmits impulse between atria and ventricles

Purkinje Fibers

Spread impulse through ventricles for contraction

Arrhythmia

Abnormal heart rhythm (a- without, rhythm, -ia condition)

Pacemaker

Device used to regulate abnormal conduction

Cardiovascular System

Transportation system of body (heart + blood + vessels)

Functions

Transports nutrients, wastes, oxygen, carbon dioxide, hormones, antibodies

Blood Amount

4–6 quarts in average adult

Arteries

Carry blood away from heart (aorta = largest)

Capillaries

Connect arterioles to venules; site of gas & nutrient exchange

Veins

Carry blood back to heart (vena cava & pulmonary veins)

Plasma

90% water; carries substances

Erythrocytes

Red blood cells; carry oxygen (erythr- red, -cyte cell)

Hemoglobin

Protein on RBCs; carries O₂ and CO₂

Leukocytes

White blood cells (fight infection)

Thrombocytes (Platelets)

Help clot blood (thromb- clot)

Circulation Pathway Step 1

Deoxygenated blood → superior & inferior vena cava → right atrium

Circulation Pathway Step 2

Right atrium → tricuspid valve → right ventricle

Circulation Pathway Step 3

Right ventricle → pulmonary valve → pulmonary arteries → lungs

Circulation Pathway Step 4

Gas exchange in lungs (CO₂ out, O₂ in)

Circulation Pathway Step 5

Pulmonary veins → left atrium

Circulation Pathway Step 6

Left atrium → mitral valve → left ventricle

Circulation Pathway Step 7

Left ventricle → aortic valve → aorta → body

Anemia

Low RBCs or hemoglobin → low oxygen delivery (symptoms: fatigue, pale, SOB)

Sickle Cell Anemia

Inherited anemia; RBCs shaped like crescents → block vessels, carry less O₂

Aneurysm

Ballooning of artery wall; risk of rupture

Arteriosclerosis

Hardening/thickening of arteries (aging)

Atherosclerosis

Fatty plaque buildup in arteries → narrowing/blockage

Congestive Heart Failure (CHF)

Heart doesn’t pump effectively → fluid buildup, edema, SOB

Hypertension

High blood pressure; risk factors: family history, obesity, smoking, stress, aging

Embolism

Foreign substance in bloodstream (air, clot, fat, bacteria) blocking vessel

Varicose Veins

Dilated, twisted veins in legs due to weak valves/blood pooling

Myocardial Infarction (Heart Attack)

Blockage of coronary arteries → heart tissue death

Pumps ___ and nutrient-rich blood to the body through blood vessels.

Oxygenated

Pumps ___ blood to the lungs for gas exchange.

Deoxygenated

The heart is located ___ the sternum and ___ the lungs.

Under; between

The average heart is about the size of a person's ___.

Fist

The largest heart ever recorded belonged to a ___.

Blue whale

The heart has ___ valves to prevent the backflow of blood.

Four

The four valves are the ___, pulmonary semilunar valve, mitral valve, and ___.

Tricuspid; aortic semilunar

The purpose of heart valves is to prevent ___ and keep blood flowing in one direction.

Backflow

Deoxygenated blood enters the right atrium through the ___ and ___ vena cava.

Superior; inferior

Blood flows from the right atrium to the right ventricle through the ___ valve.

Tricuspid

The ___ pumps blood to the lungs via the pulmonary arteries.

Right ventricle

After receiving oxygen in the lungs, blood returns to the heart through the ___ veins.

Pulmonary

Blood from the left atrium passes through the ___ valve to enter the left ventricle.

Mitral

The left ventricle pumps blood to the body through the ___.

Aorta

___ circulation moves blood from the heart to the lungs and back.

Pulmonary

___ circulation moves blood from the heart to the body and back.

Systemic

The term for when the heart contracts is ___.

Systole

The term for when the heart relaxes is ___.

Diastole

The heart's electrical signal starts at the ___ node, also known as the pacemaker.

SA

The signal moves to the ___ node and then along the bundle of ___ and Purkinje fibers, causing the ventricles to contract.

AV; His

___ occurs when the heart is too weak or stiff to pump blood effectively.

Heart failure

A ___, also called a heart attack, happens when a coronary artery is blocked.

Myocardial infarction

___ is a condition characterized by high blood pressure.

Hypertension

Coronary artery disease (CAD) affects the ___ blood vessels that supply the heart.

Coronary

Irregular electrical impulses in the atria causing an irregular heartbeat is called ___.

Atrial fibrillation (AFib)

To prevent heart disease, it is recommended to exercise ___ minutes a day and avoid smoking.

30

A heart-healthy diet includes ___, ___, whole grains, and fish.

Fruits; vegetables