Circulatory System

Consists of

• Heart

• Blood Vessels

• Blood

Function

• Transports oxygen and nutrients to the cells

• Transports carbon dioxide and metabolic waste away from the cells

Heart

• Define– Muscular, hollow

organ– Size of a clenched fist– Located in the center

of the chest, under the sternum, tipped slightly to the left

– Apex is the bottom of the heart

Layers of the Heart

• Endocardium– Epithelial tissue– Lines heart

• Myocardium– Middle layer– Cardiac muscle tissue

• Pericardium– Epithelial tissue– Covers outside of heart

Septum

Wall that divides

the heart into left

and right

Heart Chambers

• Atria (atrium)1. Right

3. Left

• Ventricle2. Right

4. Left

Heart Valves

• Tricuspid– Separates the right

atrium from the right ventricle

– Has 3 flaps

• Mitral– Separates the left

atria and the left ventricle

– Has 2 flaps

• Pulmonary valve– Separates the right

ventricle from the pulmonary artery

• Aortic valve– Separates the left

ventricle from the aorta

Cardiac Cycle

• Right and left atriums contract and work together

• Right and left ventricles contract and work together

• Systole – period of ventricular contraction

• Diastole – brief period of rest

Blood Pressure 120/70

• Diastolic– Bottom number– Heart relaxes as it

passively fills with blood

• Systolic– Top number– Highest pressure in

vessels when the ventricles contract

Pattern of Circulation • Superior and inferior vena cava• Right atrium• Tricuspid valve• Right ventricle• Pulmonary valve• Pulmonary artery• Lungs• Pulmonary veins• Left atrium• Mitral valve• Left ventricle• Aortic valve• Aorta• Arteries• Arteriole• Capillaries• Venules• Veins• Superior and inferior vena cava

Electrical Conductive Pathway

• Function– Electrical impulses in the heart cause the contraction

of the muscles– A group of nerve cells that send out an electrical

impulse which spreads out over the heart– SA Node

• Sinoatrial node• Located in the right atrium

– AV Node• Atrioventricular node• Located in the septum between the atriums and the

ventricles

• Bundle of HIS– Nerve cells in the

septum

• Right and Left Bundle Branches– Divides off Bundle of

HIS

• Purkinje Fibers– A network of nerve

fibers throughout the ventricles

EKG - Electrocardiogram

• Record of the movement of the electrical impulse as it travels through the heart

Normal EKG

Arrhythmias

• Abnormal or irregular heart rhythms

Defibrillators

• When the heart is in atrial or ventricular fibrillation, the heart must be shocked with an electrical current to stop the uncoordinated contraction and allow the SA node to regain control

Pacemakers

• A small battery powered device with electrodes that monitors the hearts activity and delivers an electrical impulse to stimulate contraction

• Fixed and demand

• Avoid electromagnetic forces like microwaves and cellular phones

Pacemakers

Blood Vessels• Arteries

– Carry blood away from the heart

– Largest is the aorta– Smaller arteries called

arterioles– After the blood leaves

the left ventricle the first branch off the aorta is the coronary arteries

– Walls are more muscular and elastic

VeinsCarry blood back to the

heart

Largest veins – superior and inferior vena cava

Veins are thinner and have less muscle tissue

Valves

Veins contain valves to prevent the backward flow of blood

CapillariesOne cell thick walls

Where the exchange of oxygen and carbon dioxide takes place

Capillary Bed

Blood

• Called a tissue because it contains many types of cells

• 4-6 quarts in the average adult

• Composed of plasma and formed elements called blood cells

• Plasma is 90% water with dissolved elements in it

Functions

• Carries oxygen from the lungs to the cells and carbon dioxide from the cells to the lungs

• Nutrients from the digestive tract to cells

• Metabolic waste from the cells to organs of excretion

• Carries heat produced by the body

• Carries hormones to body organs

Blood Types

• O, A, B, AB

• Rh factor positive or negative

Universal DonorO+

Universal Recipient

AB+

Blood Types• Out of 100 people, about:

       • 38 will be O +        • 7 will be O -        • 34 will be A +        • 6 will be A -        • 8 will be B +        • 2 will be B -        • 4 will be AB +        • 1 will be AB -

• Who Can Receive Whose Red Blood Cells:       • O - can only use O -        • O + can use O + or O -        • A - can use A - or O -        • A + can use A +, A -, O + or O -        • B - can use B - or O -        • B + can use B +, B -, O + or O -        • AB - can use AB -, A -, B - or O -       • AB + can use All Blood Types

Agglutination

Blood Cells• Erythrocytes

- Red Blood Cells RBC– Function to carry oxygen

and carbon dioxide– Live for 120 days– Shaped like a doughnut– Contains hemoglobin – a

blood protein– Amount of hemoglobin

gives blood its red color

– Carries the O2 and CO2

Leukocytes

• White blood cells - WBC• Function – fight infection• Live 3-9 days• Fight infection by

phagocytes• 5 types of leukocytes

Phagocytosis

Thrombocytes• Thrombocytes

– Platelets– Cell fragments– Formed in the bone

marrow

• Function– Clotting– Thrombus is a stationary

clot– Embolus is a moving clot

• Live– 5 to 9 days

Diseases

• Anemia– Too little RBS’s or

hemoglobin or both– Many types

Sickle Cell Anemia

Aplastic anemia

Pernicious anemia

Iron deficiency anemia

Sickle Cell Anemia

• Chronic inherited anemia

• Occurs almost exclusively in African Americans

• Cells are abnormally shaped like a sickle

• Crisis occur when they block the vessels and severe pain results

Aneurysm

• A ballooning out or weakness of an artery wall

• Usually asymptomatic• May rupture and

hemorrhage and death results

• Repair is possible if diagnosed early

Common Aneurysm SitesCerebral, Aortic, Abdominal

Repair of an Aneurysm

Arteriosclerosis

• Hardening of the arteries

• Results in the loss of elasticity and contractility

• Results of aging• Causes hypertension

Atherosclerosis

• Deposits of plaque on artery wall

• If plaque breaks loose circulates as an emboli and

Surgical Repair

• CABG– Coronary artery

bypass graft– A vein from the leg or

chest is used to go around or “bypass” the blockage

Stent

• Insertion of an expandable coil that

• Keeps the vessel open

• Some are medicated

Hemophilia

• Inherited disease that occurs mostly in males but carried by females

• Lack of a clotting factor (VII most common)

• Minor cut can cause prolonged bleeding

Hypertension

• Increased blood pressure

• Caused by a narrowing of the vessels or too much fluid in the vessel

• Controlled with medication and diet very effective

• Leading cause of stroke

Hypotension

• Low blood pressure• Due to dilation of the

blood vessels, shock, or hemorrhage

Leukemia

• Cancer of the bone marrow or lymph tissue

• Results in a high number of immature WBC”s

• Treatment– Radiation, chemo,

bone marrow transplant

Myocardial Infarction

• Heart Attack• Due to blockage in

the coronary arteries that cuts off the blood supply to the heart

• Treatment includes clot busting drugs, CABG, stents

Phlebitits

• Inflammation of a vein• If caused by a clot it is

called thrombophlebitis

Varicose Veins

• Dilated, swollen veins