The Circulatory System

Consists of the heart, the blood vessels, and blood

Functions of the Circulatory System

1.Transports O2 & nutrients (sugars, amino acids) to body cells

2.Transports hormones throughout body

3.Carries wastes away from cells

4.Works with the immune system to protect body against disease causing pathogens

Parts of the Blood

1. Plasma – fluid portion– transports all of the material

2. Red Blood Cells: (RBC’s)

a.Transports oxygen to body cells

b.Removes waste from body cells

3. White blood cells: (WBC’s)

a.Protect against infection; fight parasites & attack bacteria

4. Platelets: cell fragments

a.Release proteins that help clot blood

Plasma

Platelets

WBC’s

RBC’s

Blood Cells

Red blood cells (erythrocytes)

MOST NUMEROUS, DISK-SHAPED,

CARRIES O2 TO ALL CELLS IN THE BODY,

HEMOGLOBIN

White blood cells (leukocytes)

LARGER IN SHAPE THAN RBC BUT

FEWER IN NUMBER, HELP FIGHTS DISEASE

Blood Vessels1. Arteries: large vessels; carry blood away from heart

a.Most arteries carry O2 rich blood

2. Veins: large blood vessels; return blood to heart

a.Have valves to keep blood from flowing backwards

3. Capillaries – smallest blood vessels

a.Bring nutrients & O2 to cells

b.Absorb CO2 & wastes from body cells

arteriesveins

capillaries

Pulmonary artery

Left atrium

Left Ventricle -

Right ventricle:

Superior Vena Cava AORTA

Right atrium Pulmonary

vein

Septum

Inferior Vena Cava

Bicuspid ValveTricuspid Valve

Semilunar Valve

The Heart1. Heart – muscular organ

a. 4 chambers

b. Pumps blood from heart to lungs & back to heart, to tissues throughout body

2. Septum: muscular wall in heart

a. Separates right side from left side

b. Keeps O2 poor & O2 rich blood from mixing

The Heart3. Atria – 2 upper chambers

a. Receive blood from body (right) or lungs (left) & pump blood into ventricles

4. Ventricles – 2 lower chambers

a. Pump blood out of heart to lungs (right) or aorta (left)

2 Pathways of Circulation

blood FLOW between the heart & lungs

Rt ARt Vpulmon. Artery LUNGSL A

L ALVaortabodyvena cava Rt A

a.Transports O2 poor blood to lungs and O2 rich blood back to the heart

b. Blood travels from right side of heart to lungs

How the Heart Works: Pulmonary Circulation

c. Blood picks up O2 & releases CO2 in lungsd. O2 rich blood returned to left side of heart

Blood pumped from the right side of the heart to lungs and to left side of the heart

Pathway: Pulmonary Circulation

a. O2 rich blood exits left ventricle & enters aorta

b. O2 rich blood travels through arteries then capillaries

c. O2 diffuses out of capillaries & into cells; blood picks up CO2 & other wastes

d. Veins return O2 poor blood to right side of heart (right atria)

How the Heart Works: Systemic Circulation

Blood pumped from left side of heart to the body and back to the right side of the heart.

Pathway: Systemic Circulation

Circulatory System DiseasesLeukemia: bone marrow produces abnormal

WBCs which crowd out normal WBCs, RBCs & platelets.

Hemophilia: inherited disorder; person cannot produce clotting factors and bleeds longer than normal. Also has internal bleeding, mainly into muscles & joints.

Circulatory System Diseases

High Blood Pressure: AKA hypertension

BP 140 / 90 or higher for an extended period of time. Damage to heart & blood vessels; makes it harder to pump the heart. Can lead to stroke or heart attack

SICKLE-CELL DISEASE Red Blood Cells are mis-shapened causing blood cells to “CLOG” vessels. Hereditary

Anemia - when the blood transports too little oxygen.

Arteriosclerosis: arteries become hard & brittle because calcium is deposited in their walls. Vessels become thickened & lose elasticity. Blood pressure increases & blood clots may form.

Circulatory System Diseases

Stroke: blood clot blocks artery or a blood vessel breaks, interrupting blood flow to an area of the brain.  Brain cells begin to die & abilities controlled by that area of the brain are lost.