Post on 06-Mar-2018
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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