Download Circulatory System - Greater Atlanta Christian Schools

Circulatory System
Circulation
• Distribution of needed compounds to each cell in
the body
• Diffusion is not sufficient to do this.
• As organisms grew bigger the method of
distribution had to change to accommodate
distribution
Types of system
• Open
• Fluid not in continue vessels
• Blood pools
• Limits size of organism.
• Closed
Functions of vertebrate
circulatory system
• Nutrient and waste transport
• Nutrients are picked up in the small intestine and
delivered to the rest of the body.
• Wastes are then picked up and passed through the liver
and the kidney to be removed.
• Oxygen is picked up in the gills or lungs by the
hemoglobin in the Red Blood Cells and carried to all
functioning cells
• There it diffuses into each cell and picks up Carbon
dioxide that will eventually removed as a waste
product
Functions
continued
• Temperature regulation
• Blood flow can be directed to different areas of body
to help with temperature control
• Hormone delivery
• Hormones and other regulatory materials are
delivered through the circulatory system.
• Immune system materials transported
Vessels
• ARTERIES
• Carry blood away from the heart
• Lined with smooth muscle
• Able to contract and expand with the flow of blood
• ARTERIOLES
• Smallest arteries can adjust to blood flow
• Narrows the flow of blood
Capillaries
• Smallest vessels
• Usually no more than 1mm long.
• Blood flow is narrowed so that RBC’s are single file
• BP forces fluid out of the blood at arteriole end to
make the blood more concentrated
• Exchange of materials can happen more efficiently in
concentrated blood.
• Water move back in near the veinule end of capillary
• Excess water is drained by the lymphatic system
Veins
• Carry blood back to the heart
• Have one way valves to help keep blood from backflow
• Veinules (smallest veins) empty into veins which empty
into vena cava and then the heart
• Blow flow is aided by skeletal muscle in the extremities
Heart
• Four chambers
• Four valves
• Right side deoxygenated blood leads to pulmonary
circulation.
• Left side oxygenated blood leads to systemic
circulation
• Left side is stronger
Path of blood
through the heart
• Inferior, superior vena cava-right atriumtricuspid valve-right ventricle-pulmonary semilunar valve-pulmonary arteries-lungspulmonary veins-left atrium-bicuspid valve-left
ventricle-aortic semi-lunar valve-aorta-rest of
body
Coronary arteries
• Small coronary arteries feed the heart muscle
• If blood flow through these arteries is blocked
it can cause a heart attack
Control of the
heart beat
• Heartbeat does not need nerves to happen
• Nerves can effect the rate of the beat
• Beat is regulated by the sinoatrial node. This is a group
of cells in the right atrium
• The ventricles must contract lightly after the atrium
• The AV node delays the contraction by 0.1 seconds
Heart Sounds
• Heart sounds occur when the blood hits the
valves as they close.
• The “lub” sound is when the blood hits the avvalves (cuspids)
• The “dub” sound is made when the blood hits
the semi-lunar valves
Cardiac output
• Stroke volume is the amount of blood pumped
per beat
• Heart rate is the number of beats per minute.
• CO=HR X SV
• Normally about 5L per minute
• An increase in either HR or SV will increase
CO
• A healthy heart will beat less and have a higher
stroke volume
Oxygen
• Whole blood can carry 240 ml of
Oxygen/Liter
• Hemoglobin is most important
• Oxygen is picked in lungs and carried to rest of
body
• About 25 % is diffused at rest
• Body keeps 4-5 minutes in reserve
Blood
• AVG. person has 5L of blood
• Plasma 55% of blood-fluid part of blood that
carries a variety of dissolved substances
• This includes gases, glucose, hormones and
waste products
• Also carries proteins
• Albumen-carries lipids
• Fibrinogens-clotting
Blood continued
• Cells 45% of blood
• Red Blood Cells (RBC) (erythrocytes)
• 1ml blood= 5 million RBC’s
• Continuously made in the marrow
• Shaped like biconcave disk to increase surface area for
exchange
• Lack nucleus for more space for hemoglobin
• Live for about 4 months
• Glycoproteins on surface create different blood types
Blood continued
• White blood cells (WBC’s) (leukocytes)
• Less than 1% of cells in blood
• Part of immune system
• Platelets
• Important to
• Platelets stick to wounded area
• Cause fibrinogen to become fibrin and create clot blood
clotting
Heart Disease
• Heart attack
• Blocked coronary arteries
• Atherosclerosis
• Plaque deposits on the arterial walls
• Peripheral vascular disease
• High blood pressure