Transport in HumanTransport in Human(( 人類的運輸系統人類的運輸系統 ))

Every cell requires Every cell requires foodfood, , oxygenoxygen & & oother useful materialsther useful materials for for metabolismetabolismm (( 代謝作用代謝作用 )) ..

FoodFood

OxygenOxygen

UsefulUsefulmaterialsmaterials

Metabolism

Metabolism produces Metabolism produces toxic toxic waste productswaste products which must be which must be removed.removed.

Metabolism

Toxic waste productse.g. carbon dioxide

Many cells are far away from Many cells are far away from the small intestine and the the small intestine and the lung.lung.

O2

CO2

Food

A transport systemtransport systemis developed to increase

the efficiency ofexchange and transport

of materials.

Transport Transport SystemSystem

Blood 血液

Blood vessels 血管

Heart 心臟

Blood CellsBlood Cells

BloodPlatelet

White BloodCell

Red Blood Cell

BloodBlood

Blood cells (Blood cells ( 血細胞血細胞 )) (45%)(45%) Red blood cellsRed blood cells White blood cellsWhite blood cells Blood plateletsBlood platelets

Plasma (Plasma ( 血漿血漿 ) (55%)) (55%) 90% 90% waterwater Dissolved substances:Dissolved substances:

Dissolved food substancesDissolved food substances Plasma ProteinsPlasma Proteins WastesWastes

Red Blood CellsRed Blood Cells

carry carry oxygenoxygen from lungs to all from lungs to all parts of bodyparts of body

White Blood White Blood CellsCells

kill kill germsgerms ( ( 病菌病菌 )) help to help to defenddefend ( ( 防衛防衛 ) us against diseases) us against diseases

Blood PlateletsBlood Platelets

are involved in are involved in blood clottingblood clotting (( 凝血作用凝血作用 ))

Blood cells are produced byBlood cells are produced by bone marrowbone marrow (( 骨髓骨髓 ).).

Blood VesselsBlood Vessels

Heart

Capillaries ( 微血管 )

Vein( 靜脈 )

Artery( 動脈 )

carry blood from heart to other parts of the body

thick wall with muscles

branch into capillaries

ArteriesArteries

CapillariesCapillaries

the smallest blood vessels reach every part of the body

CapillariesCapillaries

glucoseO2

CO2, wastes

Tissue cell

have very thin walls => substances can diffuse across their walls

are the places for exchange of materials between the blood and the cells

VeinsVeins Capillaries join up to form

veins. carry blood back to heart thinner walls with less mu

scles have valves (( 瓣膜瓣膜 )) to prev

ent backflow of blood ( 血液倒流 )

How do valves preventHow do valves preventbackflow of blood?backflow of blood?

Musclecontracts

Musclerelaxes

Valves closed

Valves closed

Valves open

Valves open

Blood is propelled forward

Backflow of blood isprevented by valve.

Which one is Which one is arteryartery??Which one is Which one is veinvein? Why?? Why?

Because the wall of artery is thicker than that of vein.

HeartHeart

Structure of a HeartStructure of a HeartAorta ( 大動脈 )

Right auricle( 右心耳 )

Right ventricle( 右心室 )

Pulmonaryartery

( 肺動脈 )

Left auricle( 左心耳 )

Left ventricle( 左心室 )

Coronary blood vessels( 冠狀血管 )

- supply blood- supply bloodto the heartto the heart

AuriclesAuricles

Right

Left

From other

parts of body

From lungs

VeinsPulmonary

veins

- receive blood from body

Heart structure

VentriclesVentriclesRigh

tLeft

To lungs

To other parts of

body

PulmonaryArtery

Aorta

- pump blood out of the heart

Heart structure

Structure of a human Structure of a human heartheart

Pulmonaryartery

Vein

Rightauricle

Vein

Rightventricle

Aorta

PulmonaryveinsLeft

auricle

Valves

Leftventricle

Blood Circulation (Blood Circulation ( 血液循環血液循環 ))

Blood flow is maintainedby pumping action of theHeart.

body

DeoxygenatedBlood ( 缺氧血 )

Deoxygenated blood ( 缺氧血 ) returns from body to the right auricle.

Right auricle contracts and pump blood to the right ventricle.

Pulmonary Circulation (Pulmonary Circulation ( 肺循肺循環環 ))

Gaseous exchange ( 氣體交換 ) in lungs; blood becomes oxygenated blood ( 含氧血 )

OO22 COCO22 OxygenatedBlood

( 含氧血 )

Oxygenated blood flow back to left auricle and then to left ventricle through pulmonary vein.

Right ventricle pumps blood to lungs through pulmonary artery.

Systemic Circulation (Systemic Circulation ( 體循體循環環 ))

Left ventricle pumps oxygenated blood to all parts of body (except lungs) via aorta.

body

After flowing through body, the blood becomes deoxygenated.

body

DeoxygenatedBlood ( 缺氧血 )

The blood flows back to the heart.

OxygenatedBlood

( 含氧血 )

Double CirculationDouble Circulation ( ( 雙循環雙循環 )) Blood flows through the heart Blood flows through the heart

twicetwice in one complete in one complete circulationcirculation

Consists of 2 circuits:Consists of 2 circuits:

1.1. Connection between Connection between heart heart with lungs with lungs ..

2.2. Connection between Connection between heart heart with the rest of the body with the rest of the body ..

Is it possible that Is it possible that blood flows blood flows

backwards in backwards in heart?heart?

Why?Why?

Backflow of blood in Backflow of blood in heart is prevented by heart is prevented by

valves valves ..

Valves (Valves ( 瓣膜瓣膜 ))

Useful Useful WebsitesWebsites

http://www.ehc.com/vbody.asphttp://www.ehc.com/vbody.asp

http://www.mercksharpdohme.chttp://www.mercksharpdohme.com/disease/heart/coronary_healom/disease/heart/coronary_health/anatomy/home.htmlth/anatomy/home.html

Eating for healthy Eating for healthy transport systemtransport system

Takes in too much Takes in too much fatfat in diet will m in diet will make us put on weight easilyake us put on weight easily

Fatty foods also contain a lot ofFatty foods also contain a lot of chcholesterololesterol

Cholesterol is a fatty Cholesterol is a fatty substance found in the substance found in the bloodblood. . It is used to makeIt is used to make cell membrancell membraneses and some hormones.and some hormones.

Eating for healthy Eating for healthy transport systemtransport system

Do you remember the chart Do you remember the chart used in teaching used in teaching Diet and Diet and HealthHealth??

we can also obtain nutritive we can also obtain nutritive values of common food from values of common food from the website of the website of Centre for Food Centre for Food SafetySafety ( (食物安全中心食物安全中心 )) ：：http://www.fehd.gov.hk/niis/presearch3.http://www.fehd.gov.hk/niis/presearch3.htmlhtml

Too much cholesterol can Too much cholesterol can deposit on the deposit on the inner wallsinner walls of blood vessels and of blood vessels and harden the walls. harden the walls.

The vessels cannot expand The vessels cannot expand easily when blood is forced easily when blood is forced into them. This will result into them. This will result in in high blood pressurehigh blood pressure..

Eating for healthy Eating for healthy transport systemtransport system

Cholesterol deposits may Cholesterol deposits may block the block the coronary arteriescoronary arteries that supply that supply oxygenoxygen && nutrientsnutrients to the heart muscleto the heart muscle and and cocoronary heart diseaseronary heart disease results. results.

The heart may stop beating The heart may stop beating due to the lack of oxygen and due to the lack of oxygen and this may cause this may cause deathdeath..

Eating for healthy Eating for healthy transport systemtransport system

If there is a blockage or rupture If there is a blockage or rupture in the in the brain arteriesbrain arteries, , strokestroke may may result. This may result in result. This may result in paralysisparalysis..

To avoid the trap of cholesterol To avoid the trap of cholesterol in the bodyin the body, i, it is recommended t is recommended that we limit our average daily that we limit our average daily cholesterol intake to less than cholesterol intake to less than 300 mg300 mg..