Download Blood vessels

Ch. 8, lesson 2: How materials move to and from cells
 Body cells must have a way to get oxygen and nutrients and get rid of wastes.
 Circulatory system carries food and oxygen to the cells throughout the body
and carries waste away from the cells.
 Heart: pumps blood
 Blood vessels: carries blood
 The heart:
 Main organ of circulatory system.
 Located between the lungs in the chest cavity.
 Most powerful organ in the body
 Made of cardiac muscle (cardiac = of the heart, related to heart)
 Heart contracts and relaxes automatically in a regular rhythm  heartbeat.
 70 times/minute when adults are not active.
 100,000 times/day.
 Pumps 7,000 + L/day
 Children/teenagers = faster heartbeat
 Active adult = much faster heartbeat
 Heart contracts to push blood through blood vessels  pressure builds
inside certain vessels  blood vessel bulges  can feel a pulse.
 Inside of wrist and side of neck
 How Blood circulates:
 Heart is made up of two sides left and right
 Each side has upper chamber  Atrium (atria) and lower chamber
Ventricle
 Flow of blood through body:
 Right atrium receives blood from body Right ventricle  Lungs Left
atriumLeft ventricleaorta bodyback to Right atrium
 Blood going to the lungs is low in oxygen and high in carbon dioxide.
 Carbon dioxide leaves blood and enters the lungs to be exhaled.
 Oxygen leaves the lungs and enters the blood to be taken to cells in the
body.
 Blood vessels:
 Blood travels only in one direction in a circular pattern
 Arteries: blood vessels that carry blood away from the heart.
 Most filled with oxygenated blood
 Aorta: largest artery
 Arteries get smaller as they move away from the heart.
 Capillaries: smallest blood vessels  walls are one cell thick to allow
transfer of nutrients, gases, and wastes.
 Veins: carries blood back to the heart.
 Become larger as they get closer to the heart.
 Most carry carbon dioxide to be released into the lungs.
 Pressure is lower than in arteries.
 One way valves that prevent blood from flowing backwards.
 Some veins are squeezed by muscles to help keep blood flowing.
 Muscles in legs used when walking
 Blood Pressure:
 Force of blood against the walls of blood vessels, usually arteries.
 When heart beats, blood is pushed into arteries which causes them to bulge
slightly.
 When blood vessels don’t stretch, blood pressure rises.
 Too high  damage to heart and other organs
 Blood and its parts:
 Delivers oxygen to cells and carbon dioxide to lungs
 Delivers nutrients from digestive system and waste products to kidneys.
 Carries materials that fight infections and heals wounds.
 Liquid part  plasma
 Mostly water – half of blood
 Contains dissolved substances  oxygen, food, minerals, and vitamins.
 Contains antibodies
 Proteins that fight disease
 Help a person become immune or resist disease.
 Fights harmful microorganisms and cancer cells
 Your body makes one kind of antibody for each different foreign
substance that enters your blood stream.
 Solid parts  cells in blood
 Red blood cells
 Filled with hemoglobin
 Protein that carries oxygen
 Blood is bright red when carrying oxygen.
 White blood cells
 Fewer than red blood cells (1 WBC for every 700 RBC)
 Protect the body against foreign substances.
 WBC can move to where they are needed.
 Trap invaders or make chemicals that kill harmful germs.
 Platelets:
 Tiny cell pieces that help clot blood.
 Thick mass of blood
 No regular shapes
 Collect at the place where skin is cut  stick to each other and
blood vessel to close openings.
 Blood Types:
 Four blood types
 Type A, type B, type AB, type O
 Caused by different proteins in the RBC.
 Blood type must be identified before blood can be given to a person.
 Only certain blood types can be given to people.
 Type O = universal donor Type AB = universal recipient
 Wrong blood type will cause blood to clump and cells are deprived of
oxygen and will die.