Cardiovascular system

AKA CIRCULATORY SYSTEM

CARDIOVASULAR SYSTEM

Consists of heart, blood vessels, and blood

Transportation system

O2 and nutrients to body cells

CO2 and metabolic waste away from cells

Heart

Muscular “pump”

Located in the mediastinal cavity

Btwn lungs

Behind sternum

Above diaphragm

Three layers & septum

Endocardium—smooth inner lining

Myocardium—thick muscle middle layer

Pericardium—outer covering

Muscular wall that divides rt. & lt.

Prevents blood flow btwn rt. & lt.

Chambers Four chambers

Two upper—ATRIA

Two lower—VENTRICLES

RA receives blood as it returns from body cells

RV receives blood from RA

RV pushes blood thru pulmonary artery to lungs

LA receives oxygenated blood from lungs

LV receives oxygenated blood from LA

LV pushes blood thru aorta to be carried to the body cells

Valves

Tricuspid btwn RA & RV

Pulmonary btwn RV & pulmonary artery

Mitral btwn LA & LV

Aortic btwn LV & Aorta (largest artery)

Heartbeat Cycle

Electrical impulses originating in the heart causes the myocardium to contract

One cycle consists of a period of contraction (systole) & rest (diastole)

Atria contract to push blood into the ventricles

While atria relax & refill, ventricles contract

Heartbeat Cycle cont…

Blood in rt. Side of heart is low in O2 & high in CO2

When it gets to the lungs CO2 is released (exhaled) and O2 is picked up

So now blood in lt side of the heart is high in O2 and low in CO2

Blood Vessels Arteries

Vessels that carry blood away from the heart

AortaLargest artery in body: eventually branches into arterioles

VeinsVessels that carry blood back to the heartVenules are smallest branches Inferior & superior vena cava are largest

veins in the body

Blood Vessels cont…

Capillaries

Connect arterioles with venules

Have thin walls (one layer of cells)

Allow oxygen & nutrients to exit thru to cells

Allow carbon dioxide & waste products from cells to enter

Blood Composition 5-6 quarts circulate continually

Transports:

Oxygen

Carbon dioxide

Nutrients

Metabolic waste

Heat

Hormones

Blood Composition cont…

Plasma—fluid part, 90% water

Erythrocytes (rbc)—contains (hemoglobin) to carry iron, O2 & CO2

Leukocytes (wbc)—main function is to fight infection

Thrombocytes—aka platelets, contains enzymes for clotting

Components of blood

Diseases and conditions of the cardiovascular

system

Anemia Inadequate amount of erythrocytes,

&/or hemoglobin

Iron deficient—inadequate iron

Aplastic—caused by injury to bone marrow Little or no production of RBC: can be fatal

Pernicious—poor absorbtion of vitamin B12

Sickle cell—chronic inherited disease

Occurs almost exclusively in African-Americans

Anerurysm

Ballooning out of weak area of wall of artery

Most common sites are cerebral, aortal, and abdominal

If it ruptures, could cause death

Atherosclerosis Fatty plaques of

cholesterol on walls of arteries

Causes narrowing (stenosis)-reduces flow

If plaque breaks, it can circulate thru blood stream (emboli)

Tx is low cholesterol diet, exercise, meds

Congestive Heart Failure (CHF)

Heart muscle does not beat adequately to supply bloods needs of the body

Symptoms: edema, dyspnea, pallor, cynosis, distention of neck veins, weak, rapid pulse, cough with pink frothy sputum

Tx: drugs, diuretics oxygen therapy, bedrest, low sodium diet.

Embolus & Hemophilia

Foreign substance circulating in blood: air, blood clot, bacterial clump, fat globule

Inherited disease, where blood is not able to clotOccur almost always

in males

Hypertension

Systolic > 150 mmHg

Diastolic > 90 mmHg

Tx: medications, diuretics, lower stress, avoiding tobacco, losing wt

Leukemia

Malignant disease of bone marrow or lymph tissue

Can be acute or chronic

Tx: chemo, radiation, bone marrow transplant

Myocardial Infarction (heart attack)

Blockage in coronary artery cuts off blood supply to the heart

Affected heart tissue dies (infarct)

Myocardial Infarction (heart attack) cont…

Symptoms: severe crushing pain in chest, jaw, neck, armPressure in chestPerspirationCold clammy skinDyspneaChange in blood pressure

Tx: CPR, (inc. defibulator ad lib)AnticoagulantsMedications

Opening clogged arteries

Risk factors for cardiovascular diseases

Risk factor—factors in the environment, or chemical, physiological or genetic element, that are thought to “pre-dispose” an individual to the development of a disease

Over 1 million people a year will have a fatal episode of some type of cardiovascular disease!

Two categories of risk factors:

Things that cannot be changed: Age Heredity Gender Race

Things that can be changed Smoking Hypertension Cholesterol level Physical inactivity Obesity Excessive stress