DAY 1 – CHAPTER 15

Cardiovascular

System

Overview

Vascular System

blood circulates

inside closed transport systems

Anatomy of the Heart

General Size: approximately the size of a

person’s fist Location: in the mediastinum - the

cavity in the center of the chest

Coverings: Pericardium Double layered sac Contains roughly half an ounce of

pericardial fluid to reduce the friction of the beating heart

Parietal layer: fibrous membrane; outer layer

Visceral layer: serous membrane; also called the epicardium; attached to myocardium

Heart Wall

Myocardium: heart muscle; thicker on left side of the heart

Endocardium: lining of heart chambers; endothelial tissue continuous with the lining of the blood vessels

Chambers of the Heart

Atria 2 upper chambers of heart; thin walls, smooth inner surface Responsible for receiving blood Right atrium receives deoxygenated (oxygen poor) blood from

the body through the superior and inferior vena cava Left atrium receives oxygenated (oxygen rich) blood from the

lungs through the pulmonary veinsVentricles

2 lower chambers of the heart; thicker walls, irregular inner surface

Contain papillary muscles and chordae tendineae (prevent heart valves from turning inside out when ventricles contract)

Left wall 3x as thick as right wall; forms apex of heart Responsible for pumping blood away from the heart Right ventricle sends deoxygenated blood to the lungs via the

pulmonary arteries Left ventricle sends oxygenated blood to all parts of the body

via the aorta

Chambers of the Heart (ctd.)

Accessory Structures Septum:

muscular wall dividing the heart into right and left halves

Heart valves: prevents the backflow of blood

Papillary muscles Chordae

tendineae

Great VesselsSuperior and inferior vena cava: receive

deoxygenated blood from all parts of the bodyCoronary sinus: returns deoxygenated blood

from the myocardium to the right atriumPulmonary arteries: carry deoxygenated

blood to the lungs from the right ventriclePulmonary veins: carry oxygenated blood to

the left atrium from the lungsAorta: carries oxygenated blood to distribute

to all parts of the body

Blood Vessels

Types of Blood Vessels: Arteries Arterioles Capillary beds Venules Veins

Anatomy of Blood Vessels

Three coats (tunics):1.Tunica intima: endothelium

lines the interior of vessels; decreases friction as blood flows

2.Tunica media: smooth muscle & elastic tissue (dilates & constricts vessels)

3.Tunica externa: fibrous connective tissue on outside supports and protects vessels

ArteriesCarry blood AWAY from the heartAll BUT pulmonary arteries carry

oxygenated bloodAorta: largest artery; 1 inch in

diameterArterioles: smallest arteriesCoronary arteries: most important;

supply blood to the heart muscle Left and right main coronary artery

Left coronary artery - left anterior descending, left circumflex branch

Right coronary artery - right atrium and right ventricle

VeinsCarry blood TOWARD the

heartAll BUT pulmonary veins

carry deoxygenated bloodLayers much thinner, less

elasticSeries of internal valves

that work against the flow of gravity to prevent reflux

Superior and inferior vena cava: largest veins

Venules: smallest veins

Vericose Veins

People stand for long periods of time inactivity or pressure on veins

Blood pools in feet and legs

Valves weaken veins become twisted & dilated

Treatment: compression stockings, exercise, laser treatment, surgery

Capillaries

Tiny, microscopic vessels

Walls one cell layer thick

Function: to transport and diffuse essential materials to and from the body’s cells and the blood

ArteriesArteries CapillariesCapillaries VeinsVeins

• Blood away from heart• Thicker walls• Withstand

high pressure

• Walls 1-cell thick• Exchange

gases between blood and tissue cells

• Blood back to heart• Thinner walls• Low pressure• Large lumen• ValvesValves:

prevent blood backflow• Skeletal

muscles enhance venous return

Vital SignsPulse:

expansion & recoil of an artery with each beat of left ventricle

Pressure points (eg. carotid artery, radial artery) Normal resting: 70-

76 beats/min

DAY 2

Cardiovascular System

Cardiovascular Circuits

Pulmonary circuit: transport of blood from the right side of the heart to the lungs and then back to the left side of the heart

Systemic circuit: transport of blood from the left side of the heart to all parts of the body and then back to the right side of the heart

Coronary circuit: transport blood from the left side of the heart to the heart tissues and back to the right side of the heart

Heart Valves

Tough fibrous tissue between the heart chambers and major blood vessels of the heart

Gate-like structures to keep the blood flowing in one direction and to prevent regurgitation or backflow of blood Atrioventricular valves: when ventricles contract, blood is

forced upward and the valves close Tricuspid valve: between the right atrium and the right

ventricle Bicuspid/mitral valve: between the left atrium and the left

ventricle Semilunar Valves: 3 half moon pockets that catch blood and

balloon out to close the opening Pulmonary semilunar valve: between the right ventricle and

the pulmonary arteries Aortic semilunar valve: between the left ventricle and the

aortic arch/aorta

How the Heart Works Each heartbeat has two phases, systole when the heart

pumps and diastole when the heart chambers fill with blood. Blood enters the right atrium from the body via the vena

cava. It travels through the tricuspid valve into the right

ventricle. A systolic heartbeat sends the blood through the pulmonary

valve, which separates the right ventricle and the pulmonary artery, to the lung.

In the lung, oxygen is delivered to red blood cells and carbon dioxide, a waste product of metabolism, is removed.

The oxygenated blood returns to the left atrium where it travels through the mitral valve into the left ventricle.

The systolic heartbeat also causes the left side of the heart to contract and send the blood through the aortic valve that separates the left ventricle and the aorta.

Blood passes through the aorta to the body delivering oxygen to the body's tissues.

Heart Sounds

When the AV (atrioventricular) and semilunar valves close, they make the sound heard as “lub-dub” (auscultated with stethoscope) First sound (S1): ventricles are contracting and

forcing blood to the lungs and entire body (AV valves closing)

Second sound (S2): atria are contracting and the semilunar valves are closing

Abnormal heart sounds = murmur; valve pathology (M1, M2)

Vital SignsBlood pressure:

pressure of blood on inner walls of blood vessels

Systolic pressure: peak of ventricular contraction

Diastolic pressure: ventricles relaxedWritten:

Systolic/DiastolicNormal: 100-140;

60-90

Homeostatic Imbalances

Hypertension: high blood pressure (>140/90)

Circulatory shock: acute hypotension Blood loss Atherosclerosis – artery walls thicken due

to fatty deposits (plaques)

Bypass Surgery

One of the most common surgeries performed

During surgery, a blood vessel is removed or redirected from one area of the body and placed around the area or areas of narrowing in order to "bypass" the blockages and restore blood flow to the heart muscle. This vessel is called a graft. These substitute blood

vessels can come from your chest, legs, or arms.

Stent Procedure

A stent is a wire mesh stainless steel tube that holds an artery open and keeps it from closing again.

It becomes a permanent part of the artery.

How is it Done?

The doctor will insert a tiny, flexible plastic tube called a catheter through an artery in the groin, leg, or arm.

A special dye is injected so blood flow through the arteries is visible on monitors. 

The doctor moves a balloon catheter, and then a stent, to the site of the blockage. The balloon is inflated and stretched wide against the

artery walls, which opens the blockage.  Then the balloon is deflated and taken out, leaving the

stent in place.

Congenital Heart Disease

Defects in the heart that occurred during embryologic and fetal development

Involves defective communication between the chambers, malformation of valves, and malformation of septa Cyanotic: inability of individual to get adequate blood

oxygenation due to extensive cardiac abnormalities that cause blood to be shunted away from lungs

Some association with pregnant mother having German measles (rubella)

Congestive Heart Failure

Progressive weakening of heart

Low heart efficiency circulation inadequate to meet tissue needs

Caused by: Coronary atherosclerosis Persistent high blood

pressure Multiple heart attacks – scar

tissue