34.1 Circulatory System

Circulatory SystemSection 34.1

Circulatory System· body's transport system

delivers nutrients to cellspicks up waste from cells

· composed of blood vessels, the heart, blood and the lymphatic system· functions

transportation of nutrients/wastehelps immune system fight infectionhelps prevent blood losshelps regulate body temperature

Blood Vessels· responsible for carrying blood throughout the body· arteries - carry blood away from the heart to body

oxygen-rich bloodthick walls to accommodate high pressure

· capillaries - smallest blood vessels1 cell thickexchange nutrients and wastes with cells

· veins - cary blood from body to heartoxygen-poor bloodvalves prevent blood from flowing backward

The Heart· muscular organ about the size of your fist · double pump

pumps oxygen-rich blood to the body

pumps oxygen-poor blood to the lungs

· composed of cardiac muscle and an electrical system

Heart Structure

R ventricleInferior vena cava

Tricuspid valve

R atrium

Aorta

Superior vena cava

Aortic semilunar valve

Pulmonary semilunar valve

Pulmonary trunkL atrium

Bicuspid valve

L ventricle

· 4 chambersR and L atria receive blood returning to the heartR and L ventricles pump blood out of the heart

· R and L separated by a thick muscular wall· atria and ventricles separated by valves

Heart Beats· 2 phases

atria contractventricles contract

· sinoatrial (SA) node causes both atria to contract

responds to the body's need for oxygen

· atrioventricular (AV) node causes both ventricles to contract

34.1 Circulatory System

Pulse & Blood Pressure· pulse - represents the # of times your heart beats

about 70 times per minute· blood pressure - amount of pressure exerted against a blood vessel wall by blood

systole: contractiondiastole: relaxationnormal: 120/80 mm Hg

Blood· transports nutrients/wastes throughout the body· average adult male has about 5L

5.2 quarts or 10 pints· 55% plasma + 45% formed elements

plasma = watery fluidformed elements = cells

(RBC, WBC, platelets)

Plasma· liquid portions of blood· 90% water, 10% dissolved materials· 3 main plasma protein groups

albumins - regulate water conc. in bloodglobulins - help fight diseasefibrinogen - forms blood clots

Red Blood Cells (RBC)· small, biconcave disk shaped cells· no nuclei· develop in bone marrow· live for about 120 days· hemoglobin

carries O2 to blood cells

Platelets· cell fragments· important in forming blood clots

stick together and release a chemical that produces fibrin (a protein)

fibrin forms a web over the injury that traps platelets and RBCs forming a clot

White Blood Cells (WBC)· larger than RBC· have a nucleus· NO hemoglobin (appear white)· fewer in number· disease fighters

34.1 Circulatory System

Blood Groups· 2 systems used: ABO and Rh· antigens - protein markers that appear on the surface of cells

"Hello, my name is..."· antibodies - proteins that react with an antigen

recognize cells as friend or foe

ABO Blood Groups· 4 types

A, have A antigensB, have B antigensAB, have both A and B antigensO, no antigens

· blood with different antigens than yours is recognized as foe and clumps together

dangerous because it blocks blood flow

Rh Group· if RBC mem. has Rh antigen Rh+

· if RBC mem. lacks Rh antigen Rh-

· Rh- people do not normally have antibodies to the Rh factor, but their body produces antibodies after exposure to the Rh factor

like getting the chicken pox· next time an Rh- person comes in contact with Rh+

blood it will clump