1 2 think about… 8.1 the transport system 8.2 the blood 8.3 the blood vessels 8.4 the heart 8.5...

Think about…8.1 The transport system8.2 The blood8.3 The blood vessels8.4 The heart8.5 Blood circulationRecall ‘Think about…’Summary concept map

The patient has lost a lot of blood.

He needs blood transfusion.

donated blood

blood donor

donated blood

artificial blood

bacteria producing haemoglobin

What are thefunctions of blood in our body

What is its role in the body

What is haemoglobin2

Can artificialblood totally replace donated blood

8.1 The transport system

In our city:

• transport system to carry goods and people around

How are substances moved in organisms?

In very small organisms:

nutrientswaste

• by diffusion

In multicellular organisms:

substances need to move long distance

• by a transport system

human transport system

lymphatic system

(淋巴系統 )

circulatory system

(循環系統 )

Human circulatory system

• carries nutrients and waste

blood vessels (血管 )

• distributed throughout the body

• as a pump to drive blood

1 Humans are organisms. A is needed to carry substances from one place to another over long distances within the body.

multicellulartransport system

2 The human circulatory system consists of:

blood vessels

8.2 The blood

What is the composition?

centrifugation

Composition of blood8.2 The blood

Composition of blood

plasma

blood cells

8.2 The blood

1 Plasma

• 90% water• 10% soluble substances

8.2 The blood

• 10% soluble substances

- plasma proteins

- nutrients

- waste

- respiratory gases

- hormones

1 Plasma8.2 The blood

2 Blood cells8.2 The blood

blood platelet

red blood cellwhite blood cell

Red blood cells

White blood cells

Blood platelets

Shape Biconcave disc

Irregular Small & irregular

Red blood cells

White blood cells

Blood platelets

Nucleus

Colour

No Large No

Red Colourless Colourless

2 Blood cells

due to haemoglobin

8.2 The blood

Red blood cells

White blood cells

Blood platelets

Size Small (7-8 μm)*

Phagocyte: large (10-29 μm)* Lymphocyte: small (6-10 μm)*

< red blood cells (1-4 μm)*

* Diameter

Red blood cells

White blood cells

Blood platelets

Number (/mm3)

Function

5.4 million 7000 250 000

Carrying oxygen

Killing germs

Blood clotting

2 Blood cells

by haemoglobin

8.2 The blood

Red blood cells

White blood cells

Blood platelets

Made in

Life span

Bone marrow

Bone marrow, spleen

Bone marrow

120 days A few days A few days

Red blood cells

White blood cells

Blood platelets

Break down in

Liver and spleen

Killed by germs;

Passed out in faeces

Liver and spleen

What are the functions of blood?

8.2 The blood

Functions of blood1 Transport of substances

Red blood cells

oxygen

8.2 The blood

Functions of blood1 Transport of substances

Plasma

carbon dioxidenutrientsurea

8.2 The blood

hormonesheatantibodies

Functions of blood2 Protection against diseases

• engulfs and digests germs

Phagocyte

8.2 The blood

• produces antibodies

Lymphocyte

kill germs or neutralize toxins

8.2 The blood

• help in blood clotting

Blood platelets

prevents further blood loss and entry of germs

through the wounds

blood platelet

red blood cell

white blood cell

blood cellsplasma

8.2 The blood

carries heat and

2 Functions of blood:

Plasma

dissolvedsubstances

8.2 The blood

contain to carry oxygen

Red blood cells

haemoglobin

8.2 The blood

protect us against

White blood cells

diseases

8.2 The blood

help in

Blood platelets

blood clotting

8.2 The blood

8.3 The blood vesselsThree types of blood vessels

• arteries• veins• capillaries

arteries

arterioles

capillaries

venules

venae cavae

capillary network (微血管網 )

arteriole (小動脈 )

artery (動脈 )

venule (小靜脈 )

vein (靜脈 )

8.3 The blood vessels

Arteries and veins

artery vein

Arteries and veins

artery

thin layer of fibrous tissue

smaller lumen

thick layer of muscles and elastic tissue

thicker wall

Arteries and veins

thick layer of fibrous tissue

thin layer of muscles and

elastic tissue

thinner wall

larger lumen

Arteries and veins8.3 The blood vessels

Why do arteries have a thicker muscular wall?

artery vein

contracts and relaxes

diameter changed

regulates amount of blood flow

thick muscular wall

Arteries and veins

Arteries and veins8.3 The blood vessels

Why do artery walls contain more elastic fibres?

artery vein

when heart relaxes

arteries recoil (反衝 )

continuous blood flow

Arteries and veins

Arteries and veinsVein Artery

Direction of blood flow

Away from the heart

Towards the heart

arteryvein

Nature of blood

OxygenatedDeoxygenated

oxygenated blooddeoxygenated blood(not in pulmonary vein and umbilical vein)

(not in pulmonary artery and umbilical artery)

Wall Thinner Thicker

arteryvein

(fewer elastic fibres)

(more elastic fibres)

Lumen Large Small

small lumenlarge lumen (resistance )

Blood pressure

Low High

due to pumping of heart

due to resistance in capillaries

Force for blood flow

Contraction of muscles

Pumping of heart

blood flow

pumping contraction

blood flow

squeeze veins

Presence of valves

Present Absent

except at the base of pulmonary artery and aorta

prevent backflow of blood

Arteries and veins

veinvalve

muscle

1 Muscles contract.

2 They press against the vein.

to heart

Arteries and veins3 The vein is

squeezed.

4 The blood is forced to flow.

to heart

Arteries and veinsto heart

5 Muscles relax.

6 Valves prevent blood from flowing back.

Location Close to body surface

Deep inside the body

capillary network (微血管網 )

arteriole (小動脈 )

artery (動脈 )

venule (小靜脈 )

vein (靜脈 )

Capillaries

small lumen

one-cell thick capillary wall

differentially permeable

Capillaries

outside

inside

capillary wall

Capillaries

• small substances, e.g. O2, glucose and metabolic waste can pass through

outside

inside

Capillaries

• blood cells and proteins are too large to pass through

outside

inside

1 Wrap a small living fish in moist paper towels and put it in a Petri dish. Put a slide over the tail fin.

Examination of the capillary flow in a fish tail fin

2 Using low power magnification of a microscope or an image analysing device, observe the movement of blood in the capillary network in the tail fin.

red blood cell

Results of observation

The blood flow in the capillary network is quite slow. The direction of flow is one way. Red blood cells have a similar diameter to that of the capillaries.

red blood cell

Blood pressurebl

arteryarteriole

pumping of heart:• blood pressure

high & changes periodically

Blood pressurebl

artery

narrow diameter:• high resistance

blood pressure drops

capillaryarteriole

Blood pressurebl

artery

long distance from heart:• great friction

blood pressure further drops

capillaryarteriole venule

aorta arteries

pumps blood into

branches into

branch into

drain blood into

join to form

arterioles

capillaries

venules

branch into a network of

(exchange of materials)

join to form

aorta arteries

veinsvenae cavae

pumps blood into

branches into

branch into

drain blood into

join to form

22 Arteries:• carries blood

(except artery and artery)

oxygenated

pulmonaryumbilical

22 Arteries:• wall contains thick layer of muscles to regulate the blood flow

• elastic fibres recoil to maintain blood flow

muscles

elastic

22 Veins:• carries blood

(except vein and vein)

deoxygenated

pulmonaryumbilical

22 Veins:• lumen to reduce resistance to blood flow

• present to prevent backflow of blood

valvesbackflow

blood flows in one direction

22 Capillaries:• allows exchange of materials between blood and body cells

exchange

contraction of muscles lying next to the veins

pumping action of the heart

3 Movement of blood:In arteries: pumping action

In veins: contraction

a great due to narrow diameter

4 Blood pressure:high

In arteries:

In arterioles:

In capillaries:

gradually

becomes even as the blood has overcome great friction and travelled a long distance

4 Blood pressure:

friction

In veins: lower

8.4 The heart3D Model

• in the thoracic cavity between the two lungs

8.4 The heart

• about the size of a fist (拳 )

8.4 The heart

• weighs about 300 g

8.4 The heart

• surrounded by pericardium (圍心膜 )

8.4 The heart

• mainly made up of cardiac muscles (心肌 )

Structure of the heart

left atrium (左心房 )

left ventricle (左心室 )

right atrium (右心

right ventricle (右心

8.4 The heart

aortapulmonary arterypulmonary veins

coronary artery

coronary vein

anterior vena cava

posterior vena cava

8.4 The heart

Structure of the heart• coronary arteries (冠狀動脈 )

- receive blood from aorta- supply oxygen and nutrients to

cardiac muscles

• coronary veins (冠狀靜脈 )

- carry away carbon dioxide and waste

8.4 The heart

Structure of the heart8.4 The heart

left atrium

left ventricle

right atrium

8.4 The heart

right ventricle

pulmonary veins

pulmonary artery

anterior vena cava

posterior vena cava

8.4 The heart

bicuspid valve

septum

tricuspid valve

semilunar valves

8.4 The heart

Structure of the heart8.4 The heart

• septum prevents mixing of blood on the two sides

deoxygenated blood

oxygenated blood

left atrium

left ventricle

right atrium

8.4 The heart

right ventricle

Atria• thin muscular wall

8.4 The heart

deoxygenated blood from head & arms

anterior vena cava

8.4 The heart

deoxygenated blood from head & arms

deoxygenated blood from legs & abdomen

oxygenated blood from lungs

posterior vena cava

pulmonary veins

8.4 The heart

left atrium

left ventricle

right atrium

8.4 The heart

right ventricle

Ventricles8.4 The heart

• thick muscular wall

Ventricles8.4 The heart

• left ventricle has thicker muscular wall

right left

Ventricles

left atriumright atrium

left ventricleright ventricle

pulmonary artery

lungsrest of body

8.4 The heart

Animation

bicuspid valvetricuspid

semilunar valves

8.4 The heart

septum

8.4 The heart

Heart valves

8.4 The heart

Heart valves

tricuspid valve (3 flaps)

bicuspid valve (2 flaps)

aortapulmonary arterysemilunar

valves

Heart valvesBicuspid valve and tricuspid valve

8.4 The heart

• prevent backflow of blood into atria

8.4 The heart

• held by tough heart tendons (心腱索 )

8.4 The heart

• held by tough heart tendons (心腱索 )

prevent valves from turning inside out

Heart valvesSemilunar valves

8.4 The heart

• prevent backflow of blood into ventricles

1 Identify the left and right sides, the dorsal and ventral sides, and the major blood vessels of a pig heart.

Dissection and examination of a pig heart

8.4 The heart

2 Run water slowly into each of the four major blood vessels in turn. Observe what happens.

8.4 The heart

ventral side

8.4 The heart

3 Cut the ventricles from the bottom into two halves horizontally. First along the left side, then along the middle and lastly along the right side. Remove the ventral halves of the ventricles.

4 Cut the atria into two halves to show the valves. Remove the ventral halves of the atria. Cut open the base of the pulmonary artery and identify the semilunar valves inside.

pulmonary artery

8.4 The heart

5 Move the pulmonary artery sideways to the left. Then cut open the base of the aorta and identify the semilunar valves inside.

8.4 The heart

Adaptation of the heart as an effective pumping organ

1 Cardiac muscles can contract and relax continuously

8.4 The heart

2 Ventricles have thick muscular wall

8.4 The heart

3 Bicuspid valve, tricuspid valve and semilunar valves prevent backflow of blood

8.4 The heart

4 Heart tendons prevent bicuspid and tricuspid valves from turning inside out

8.4 The heart

1 The supply oxygen and nutrients to the cardiac muscles.

The carry away carbon dioxide and other waste from the cardiac muscles.

coronary arteries

coronary veins

8.4 The heart

2 The heart consists of four chambers:

left atrium

left ventricle

right atrium

right ventricle

8.4 The heart

2 Valves also present to prevent backflow of blood:

bicuspid valve

semilunar valves

tricuspid valve

8.4 The heart

3 Blood vessels that carry blood into and out of the heart:

carry deoxygenated blood into the heart

venae cavae

8.4 The heart

carries deoxygenated blood to the lungs

pulmonary artery

8.4 The heart

carry oxygenated blood into the heart

pulmonary veins

8.4 The heart

carries oxygenated blood to all parts of body

8.4 The heart

8.5 Blood circulation

blood circulation

pulmonary circulation (肺循環 )

systemic circulation (體循環 )

pulmonary veins

venae cavae

pulmonary circulation

pulmonary artery

right left

pulmonary veins

venae cavae

pulmonary artery

all other parts of the body

systemic circulation

right left

blood circulation

pulmonary circulation (肺循環 )

systemic circulation (體循環 )

1 Pulmonary circulation

1 Right ventricle contracts.

2 Deoxygenated blood is pumped to the lungs.

pulmonary artery

3 Gas exchange takes place.

4 Oxygenated blood returns to the left atrium.

pulmonary veins

2 Systemic circulation

1 Oxygenated blood flows from left atrium to left ventricle.

body parts (except lungs)

2 Left ventricle contracts.

3 Blood is pumped to all body parts (except the lungs).

4 Exchange of materials takes place, the blood becomes deoxygenated.

5 Deoxygenated blood returns to the right atrium through veins.

venae cavae

head, neck, arms

anterior vena cava

2 Systemic circulationaorta

posterior vena cava

hepatic artery

liverhepatic vein

small intestine

hepatic portal vein(nutrient-rich blood)

posterior vena cava

1 After digestion, nutrient-rich blood is passed to liver through hepatic portal vein.

posterior vena cava2 The blood then

flows through hepatic vein and posterior vena cava to the heart.

The pumps deoxygenated blood through the to the lungs for gas exchange.

1a In the pulmonary circulation:

right ventricle

pulmonary arterylungs

The oxygenated blood flows through to the .

1a In the pulmonary circulation:

left atriumpulmonary veins

1b In the systemic circulation:

The oxygenated blood flows from the left atrium to the left ventricle .left ventricle

The left ventricle then pumps the blood through to all parts of the body except the lungs .lungs

Exchange of materials takes place in the capillary bed. The blood becomes .deoxygenated

The deoxygenated blood returns to the through the .

right atriumvenae cavae

What are the functions of blood in our body?1

Blood is the transport medium in our body. It is also important in protecting us against diseases.

What is haemoglobin? What is itsrole in the body?2Haemoglobin in red blood cells acts as oxygen carriers.

Can artificial blood totally replacedonated blood? Why?3

Artificial blood consisting mainly of haemoglobin can carry oxygen to the organs. However, it cannot serve for other functions of blood, such as defence against diseases and blood clotting.

is provided by

Transport in humans

circulatory system

consists of

blood blood vessels

lymphatic system

made up of

plasma blood cells

red blood cells

include

blood platelets

white blood cells

1 2 think about… 8.1 the transport system 8.2 the blood 8.3 the blood vessels 8.4 the heart 8.5...

blood blood vessels

donated blood slide

functions of blood

lot of blood

blood transfusion

transport system slide

artificial blood bacteria

germs blood clotting

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