Transport in Humans- 2013- Lesson4- Blood Vessels

8/11/2019 Transport in Humans- 2013- Lesson4- Blood Vessels

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-Lesson 4 - Types of Blood vessels

-_ Blood vessels of the body.


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Lesson 4 Objectives:Students shall be able to

describe the structures of arteries , veins andcapillaries.

associate their structures to their functions.

Identify the major blood vessels of the body.


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What are blood vessels?

passageways through which blood isdistributed from heart to all parts of bodyand back to heart

Students shall be able todescribe the structures of arteries , veins and capillaries.


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Blood vessels


Arteries - carry blood away from heart

Arterioles- small arteries that deliverblood to capillariesCapillaries thin walled vessels allow forexchange between blood and tissue cells

Venules - collect and drain blood into

veinsVeins - return blood to heart


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Observe the images of the blood vessels and list atleast 2 characteristics for each ofthem.


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Arteries Carry blood awayfrom the heart

Carries blood at high pressure

Carry oxygenatedblood (except for the pulmonary

artery) Thick muscular walls 3 layers

Thin toughouter layer

Thick elastic and muscular middle layer

Thin inner layer of cells Small lumen

Do have a pulse

No valves


How are thesestructural featuresrelated to the

function ofarteries?


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Arteries Carries blood at high pressure so that it reaches

every cell in the body

Thick muscular walls to withstand the high

pressure of flow of blood & control blood supplyto the organs

Elastic walls to allow stretch and recoil

Small lumen to help maintain pressure for flow

Do have a pulsecorresponding to the contraction

and relaxation of the ventricles

No valves - pressure of flow does not permitbackflow

Students shall be able todescribe the structures of arteries , veins and capillaries.associate their structures to their functions.


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Veins Carry blood towardthe heart Carry blood at Low pressure

Carry deoxygenatedblood (except for the pulmonary

vein) Thinner more flexible walls 3 layers

Thick tough outer layer

Muscular middle layer

Thin inner layer of cells

Large lumen

Does not have a pulse

Valves present



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Veins Carry blood towardthe heart Carry blood at Low pressure no pump to return

blood to the heart

Carry deoxygenatedblood (except for the pulmonaryvein) oxygen diffused to the tissues

Thinner more flexible walls due to low pressure

Large lumen - no resistance to return of blood to

the heart

Does not have a pulse no pump to push it

Valves present to prevent backflow since blood is

returning to the heart



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Capillaries Penetrate all tissues

Very narrow only one cell wide

One cell thick wallsallows transport of oxygen and

nutrient into body cells and wastes out of cells



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Arteries VeinsTransport blood away fromthe heart; Transport bloodtowards the heart;

CarryOxygenatedBlood

(except in the case of the Pulmonary Artery);

Carry De-oxygenatedBlood

(except in the case of the Pulmonary Vein);

Have relatively narrow lumens(see diagram above); Have relatively wide lumens(see diagram above);

Have relatively more muscle/elastic tissue; Have relatively less muscle/elastic tissue

Transports blood under higher pressure(than veins); Transports blood under lower pressure(than arteries);

Do not have valves(except for the semi-lunar valves of

the pulmonary artery and the aorta).

Have valvesthroughout the main veins of the body.

These are to prevent blood flowing in the wrong

direction, as this could (in theory) return waste

materials to the tissues

Students shall be able todescribe the structures of arteries , veins and capillaries.associate their structures to their functions.


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Students shall be able to

outline the blood vessels of the body

Transport in Humans- 2013- Lesson4- Blood Vessels

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