9.2 mammalian circulatory system

8/9/2019 9.2 Mammalian Circulatory System

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process by which substances move in or out of cells or aredistributed within cells and organisms

What is transported?

Oxygen and nutrients are supplied to cells while carbondioxide and metabolic wastes are taken away from cells.

Why is transport needed?1) Cells must receive required materials and get rid of waste

materials.2) The cells of a complex organism must be in contact with theoutside environment to exchange material.

Transport for us is accomplished by our circulatory system.


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1) a fluid to carry the materials - blood

2) a system of tubes (blood vessels) or bodyspaces through which to move the fluid

arteries, veins, capillaries

3) a pumping mechanism to move the fluid

through the tubes/body spaces heart

http://videos.howstuffworks.com/hsw/16766-introduction-to-the-circulatory-system-video.htm


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C & C

1) Open Circulatory System (arthropods, mollusks)- blood is not contained within tubes, yet directlyflows over body tissues in body spaces.

- blood is under very low pressure but is movingfast enough to meet the needs of the organism

2) Closed Circulatory System (earthworms)- blood is contained within a network of tubes.- blood is under pressure which causes it to movefaster


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Closed, complete, double system.

Blood vessels organized into 3 primary cycles:1. Cardiac circulation: route taken by the blood within the

heart.

2. Pulmonary circulation: flow of blood between heart andlungs.

3. Systemic circulation: route from heart to rest of body.

http://www.bbc.co.uk/schools/gcsebitesize/pe/appliedanatomy/0_anatomy_circulatorysys_rev1.shtml
http://www.bbc.co.uk/schools/gcsebitesize/pe/appliedanatomy/0_anatomy_circulatorysys_rev1.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/pe/appliedanatomy/0_anatomy_circulatorysys_rev1.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/pe/appliedanatomy/0_anatomy_circulatorysys_rev1.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/pe/appliedanatomy/0_anatomy_circulatorysys_rev1.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/pe/appliedanatomy/0_anatomy_circulatorysys_rev1.shtml


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carry blood away from the heart

carries oxygenated blood.

Thick, elastic walls which enable them towithstand the high blood pressure created by

hearts beating.

no valves needed

as an artery enters a tissue or organ it divides

to form smaller arteries called arterioles.


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The ARTERY

thick muscle and elastic

fibres

Arteries carry blood away from the heart.

the elastic fibres allow the artery to

stretch under pressure

the thick muscle can contract topush the blood along.


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carry blood towards the heart.

carry deoxygenated blood.

thin wall, less elastic tissue because blood pressure is much lower

in veins One-way valves that keep blood moving toward heart. When these valves do not work properly, blood builds up within

the veins resulting in varicose veins. veins branch smaller and smaller to form venules.

Exceptions: pulmonary artery carries O2 poor blood from heart tolungs, pulmonary vein returns O2 rich blood from lungs back toheart to be pumped into systemic circulation.


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The VEIN

Veins carry blood towards from the heart.

thin muscle and elasticfibres

veins have valves which act to stopthe blood from going in the wrongdirection.

body muscles surround the veins so that when theycontract to move the body, they also squeeze theveins and push the blood along the vessel.


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microscopic blood vessels which are only 1 cell layer thick.

Blood cells pass through in single file.

regulate movement of fluids into and out of blood stream.

connect arterioles to venules.

http://www.bbc.co.uk/schools/gcsebitesize/pe/appliedanatomy/0_anatomy_circulatorysys_rev3.shtml
http://www.bbc.co.uk/schools/gcsebitesize/pe/appliedanatomy/0_anatomy_circulatorysys_rev3.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/pe/appliedanatomy/0_anatomy_circulatorysys_rev3.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/pe/appliedanatomy/0_anatomy_circulatorysys_rev3.shtmlhttp://www.bbc.co.uk/schools/gcsebitesize/pe/appliedanatomy/0_anatomy_circulatorysys_rev3.shtml


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The CAPILLARY

Capillaries link Arteries with Veins

the wall of a capillaryis only one cell thick

they exchange materials between theblood and other body cells.

The exchange of materials between the

blood and the body can only occurthrough capillaries.


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http://www.klbschool.org.uk/interactive/science/heart_hlp.htm

http://videos.howstuffworks.com/hsw/17092-the-circulatory-system-the-blood-vessels-video.htm
http://www.klbschool.org.uk/interactive/science/heart_hlp.htmhttp://www.klbschool.org.uk/interactive/science/heart_hlp.htm


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Blood

Helps maintain homeostasis inorganisms.

Complex mixture of cells, water, and

various proteins and sugars.

Contains many dissolved and suspendedmaterials that travel through the vesselsto every part of the body.

55% is plasma (liquid).

45% is solid.

http://videos.howstuffworks.com/hsw/5950-blood-the-components-of-blood-video.htm
http://videos.howstuffworks.com/hsw/5950-blood-the-components-of-blood-video.htmhttp://videos.howstuffworks.com/hsw/5950-blood-the-components-of-blood-video.htmhttp://videos.howstuffworks.com/hsw/5950-blood-the-components-of-blood-video.htmhttp://videos.howstuffworks.com/hsw/5950-blood-the-components-of-blood-video.htmhttp://videos.howstuffworks.com/hsw/5950-blood-the-components-of-blood-video.htmhttp://videos.howstuffworks.com/hsw/5950-blood-the-components-of-blood-video.htmhttp://videos.howstuffworks.com/hsw/5950-blood-the-components-of-blood-video.htmhttp://videos.howstuffworks.com/hsw/5950-blood-the-components-of-blood-video.htmhttp://videos.howstuffworks.com/hsw/5950-blood-the-components-of-blood-video.htmhttp://videos.howstuffworks.com/hsw/5950-blood-the-components-of-blood-video.htmhttp://videos.howstuffworks.com/hsw/5950-blood-the-components-of-blood-video.htmhttp://videos.howstuffworks.com/hsw/5950-blood-the-components-of-blood-video.htmhttp://videos.howstuffworks.com/hsw/5950-blood-the-components-of-blood-video.htmhttp://videos.howstuffworks.com/hsw/5950-blood-the-components-of-blood-video.htmhttp://videos.howstuffworks.com/hsw/5950-blood-the-components-of-blood-video.htm


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Blood is considered a liquid tissue which has 3 major functions:

1. Transportation oxygen and nutrients are sent to the bodyscells. Wastes are carried away from cells to organs where wastesare removed.

2. Regulation chemical messengers are produced and releasedin one part of the body and carried by the blood to other areas,which regulate cell activity. Blood will also regulate things such asbody temperature, pH level and water balance.

3. Protection blood carries specialized cells and chemicals whichdefend the body against disease causing organisms.

** Also helps to regulate body temperature.


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whats in

red blood cells white blood cells

platelets

plasma

carbon dioxide

digested food

waste (urea)

hormones

oxygen


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straw coloured liquid portion of blood made mostly of water with a variety of dissolved

substances in it (e.g. salts, glucose, etc.)

3 major proteins are present in plasma:1. Albumin (keeps water from leaving the bloodand entering surrounding cells through osmosis)2. Fibrinogen (involved in blood clotting)

3. Globulins (some involved in transport ofproteins, others are antibodies proteins that helpdestroy foreign substances in the body)

http://videos.howstuffworks.com/hsw/5951-

blood-plasma-video.htm


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Plasma

A straw-

coloured liquid

that carries the

cells and the

platelets which

help blood

clot.

carbon dioxide

glucose

amino acids

proteins

minerals

vitamins

hormones waste materials

like urea.

It also contains useful

things like;


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carry oxygen and carbon dioxide

contain no nucleus

Contain haemoglobin (which contains iron) whichgives them their characteristic red colour and helpsthem carry oxygen.

made in the bone marrow

average life span of 120 days and are removed fromthe blood by the spleen, liver, bone marrow, or lymphnodes when they are worn out.


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Anemia: condition caused by low levels of red blood cellsand hemoglobin.

These conditions will lower the amount of oxygen a

person can carry in their blood. Therefore the cells of thebody will not receive enough oxygen.

Anemia can be caused by the following:

Loss of blood due to injury,

Infestations of blood-sucking parasites, or

Low levels of red cell production due to poor nutrition.


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Red Blood Cells

contain haemoglobin, a

molecule specially designed tohold oxygen and carry it to cells

that need it.

can change shape to anamazing extent, without

breaking, as it squeezes single

file through the capillaries.

a biconcave disc that is round

and flat without a nucleus


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colourless blood cellswith a nucleus

Number increase when

body is fightinginfection.

these protect the bodyfrom disease causing

organisms.

produced in bonemarrow and lymphaticsystem


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1. Neutrophils - fight disease by migrating to the point ofinfection, absorbing bacteria, and destroying them. (phagocytosisof small particles)

2. Monocytes (phagocytosis of large particles)

3. Eosinophils (release clot-digesting enzyme, also combat allergy-causing substances); They contain most of the histamine proteinin the blood, which is an indication of allergic reaction whenelevated.

4. Basophils (release an anticoagulant and a histamine);responsible for the symptoms of allergies, including inflammation

5. Lymphocytes (produce antibodies and cells that destroy foreigncells and substance)


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Neutrophil (purple) migrating through tissue to enbacteria through phagocytosis.

Basophils

Monocyte

Lymphocyte


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White Blood Cells

there are many different types and all

contain a big nucleus.

the two main ones are the lymphocytes

and the macrophages.

some lymphocytes fight disease by making antibodies to destroy invaders

by dissolving them.

other lymphocytes make antitoxins to break down poisons.

macrophages eat and digest micro-

organisms .


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4. Platelets

cell fragments that are involved inblood clotting.

produced in bone marrow and live forabout 7 days.

Contain proteins on their surface thatallow them to stick to breaks in theblood vessel wall and also to stick toeach other and change shape.

Contain granules that can secreteother proteins required for creating afirm plug to seal blood vessel breaks.


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Platelets

Platelets are bits of cell

broken off larger cells.

Platelets produce tiny

fibrinogen fibres to

form a net. This net

traps other blood cellsto form a blood clot.


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The tears in the blood vessel are quickly

patched over with a solid mass o blood called

a blood clot. The process of solidification ofblood at the site of injury is called clotting.


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When a tear is found in the blood vessel, the plateletsof the blood will clump at the site of the rupture. Ifthe tear is minor, the platelets will seal the leak. If thetear is more serious, then blood clotting is triggered.

1. Platelets at the site of the tear will release anenzyme called thromboplastin

2. Thromboplastin will initiate a series of enzyme-controlled reactions to turn prothrombin intothrombin

3. The thrombin (an enzyme) will convert solubleplasma fibrinogen into insoluble strands offibrin.

4. This fibrin will form a network of strands that trapsred blood cells and platelets to form a clot.


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Fibrin is a thread-like mass produced by

fibrinogen (fibrous protein in blood) and

thrombin. Fibrin holds the red blood cells, white blood

cells, and platelets together to form a blood

clot. http://videos.howstuffworks.com/hsw/8463-

blood-thrombocytes-video.htm
http://videos.howstuffworks.com/hsw/8463-blood-thrombocytes-video.htmhttp://videos.howstuffworks.com/hsw/8463-blood-thrombocytes-video.htmhttp://videos.howstuffworks.com/hsw/8463-blood-thrombocytes-video.htmhttp://videos.howstuffworks.com/hsw/8463-blood-thrombocytes-video.htmhttp://videos.howstuffworks.com/hsw/8463-blood-thrombocytes-video.htmhttp://videos.howstuffworks.com/hsw/8463-blood-thrombocytes-video.htmhttp://videos.howstuffworks.com/hsw/8463-blood-thrombocytes-video.htmhttp://videos.howstuffworks.com/hsw/8463-blood-thrombocytes-video.htmhttp://videos.howstuffworks.com/hsw/8463-blood-thrombocytes-video.htm


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Clots are formed to stop the bleeding. They willeventually contract and harden. This will allow timefor the growth of new cells to replace the cellsdamaged by the injury. When the new cells have

taken over, a plasma enzyme called plasmin isactivated and dissolves the blood clot.

What prevents blood clots from forming in anuninjured vessel?

a. the smoothness of the inner wall of the vesselprevents platelets form becoming activated.

b. there are substances in the blood which act asanticoagulants.


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people may not have enough platelets in their blood or lackvitamin K (needed for the synthesis of prothrombin). This willcause problems in their ability to form blood clots, which has beennamed haemophilia.

people with haemophilia are able to receive injections of themissing clotting factor to prevent over-bleeding.

clots may also be able to form inside uninjured vessels, which cantravel throughout the circulatory system. This may cut off orreduce the blood flow to an organ. For example, a heart attackmay be caused b a clot forming in the coronary artery.

These failures can be prevented or their damage can be limited byinjecting an enzyme into the blood stream, which digests bloodclots within the first few hours of a heart attack or other organfailure.


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SUMMARY

Arteries take blood _____ from the heart. The walls of an artery are made up of

thick _________ walls and elastic fibres. Veins carry blood ________ the heart

and also have valves. The _________ link arteries and veins, and have a one cell

thick wall. Blood is made up of four main things ______, the liquid part of the

blood; Red Blood Cells to carry ______; White Blood cells to protect the body

from disease and _________ to help blood clot.

away

platelets

towards

capillaries

plasma

oxygen

muscular

9.2 mammalian circulatory system

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