Cardiovascular System

The Cardiovascular System is part of the Anatomy and Physiology section which provides High Yield information for the MCAT exam needed for Medical School.

Cardiovascular System

Pulmonary Circuit

2119 Pulmonary Circuit
OpenStax College / CC BY

Systemic Circuit

2101 Blood Flow Through the Heart
OpenStax College / CC BY

Arteries and Veins

ArteryA blood vessel that carries oxygenated blood away from the heart to vital organs and the extremities.
ArteriolesSmall-diameter blood vessels that extend and branch out from an artery and lead to capillaries; the primary site of vascular resistance.
CapillariesThe smallest blood vessels that supply blood to the tissues, and the site of all gas and nutrient exchange in the cardiovascular system. They connect the arterial and venous systems.
VenulesSmaller divisions of veins.
VeinsBlood vessels that carry deoxygenated blood toward the heart from vital organs and the extremities.

Arterial Diseases

ArteriosclerosisA chronic disease in which thickening, hardening, and loss of elasticity of the arterial walls result in impaired blood circulation; develops with again, and in hypertension, diabetes, hyperlipidemia, and other conditions.

Arterial and Venous System

Circulatory System en
LadyofHats / Public domain

Blood Composition

BloodThe fluid component of the cardiovascular system that links the internal environment of the body to the external environment by transporting materials between the two environments as well as among the various cells and tissues. Therefore, its primary function is transportation.
PlasmaThe liquid portion of the blood responsible for carrying hormones, plasma proteins, food materials (e.g., carbohydrates, amino acids, lipids), ions (e.g., sodium, chloride, bicarbonate), and gases (e.g., oxygen, nitrogen, carbon dioxide) throughout the body.
PlateletsOne of the disc-shaped components of the blood; involved in clotting.
Red blood cellsContains hemoglobin to transport oxygen
White blood cellsInvolved in protecting against infection
Amount of Blood in the Body4.7 Litres in the average Human body
Four Blood TypesA, B, O, AB

Heart Anatomy

HeartServes as a pump, pushing blood throughout the body; located between the lungs and lies just left of center, behind the sternum; divided into four chambers, and is often considered two chambers in one, as the right two chambers are responsible for pulmonary circulation and the left two chambers are responsible for systemic circulation.
AortaLargest artery in the body
The large arterial trunk that carries blood from the heart to be distributed by branch arteries through the body.
Atriumthe top two chambers of the heart
VentricleBottom portion of the heart, thicker-walled and larger
Each of the two lower chambers of the heart that pumps blood out of the heart
Interventricular SeptumMuscular wall that separates the right and left sides of the heart, preventing the mixing of blood from the two sides of the heart.

Blood Flow thru the heart

Vena cavaBrings deoxygenated blood from systemic circulation into the right atrium
Right atriumDeoxygenated blood from systemic circulation enters the heart here
Tricuspid valveBetween the right atrium and ventricle
Right ventricleThis chamber receives deoxygenated blood from the right atrium and sends it out through the pulmonary artery to the lungs
Pulmonary valveValve between right ventricle and pulmonary artery
Pulmonary arteryThis vessel carries deoxygenated blood from the right ventricle to the lungs
Pulmonary veinThis vessel carries oxygenated blood from the lungs to the left atrium
Left atriumThis chamber receives oxygenated blood from the lungs
Bicuspid valveBetween the left atrium and ventricle
Left ventricleThis chamber receives oxygenated blood from the left atrium and pumps it into the systemic circulation through the aorta
Aortic valveValve between left ventricle and aorta
AortaThis vessel transports oxygenated blood from the left ventricle into the systemic circulation
Diagram of the human heart (cropped)
Wapcaplet / CC BY-SA

Electrical conduction of the heart

(SA) node
this node is known as the pacemaker of the heart. Controls the pace and rhythm of the heart beat
(AV) node
small mass in the lower septum of the right atrium that passes impulses from the sinoatrial node toward the ventricles
Bundle of Hisa collection of heart muscle cells specialized for electrical conduction that transmits the electrical impulses from the AV node (located between the atria and the ventricles) to the point of the apex of the fascicular branches via the bundle branches.
a bundle of the modified heart muscle that transmits the cardiac impulse from the atrioventricular node to the ventricles causing them to contract

Clinical and Physiological Values

Heart ratea measure of cardiac activity usually expressed as the number of beats per minute
Cardiac CycleThe period from the beginning of one heartbeat to the beginning of the next heartbeat; the systolic and diastolic phases and the interval in between.
reflects the force the blood exerts against the walls of the arteries during contraction (systole) and relaxation (diastole) of the heart
the pressure generated by the left ventricle during systole
Diastolic pressureblood pressure that remains between heart contractions
Pulse pointplace where artery may be compressed against bone with fingertips to feel pulse
Radial pulsethe pulse located on the inside of the wrist, where the radial artery runs just beneath the skin; thumb side of arm
Brachial pulsebeating or throbbing felt over the brachial artery, usually palpated in the antecubital space
Apical pulseA method of determining heart rate by placing the stethoscope over the apex of the heart


Blood functions1. Transport
2. Protection
3. Regulation

Heart Anatomy MC