CHAPTER 2 : BLOOD CIRCULATION & TRANSPORT 2.1 : Transport

System in� Human �

2.2 : Human blood�2.3 : Transport

System in Plants �

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.1 : Transport System in Human General Structure of the Human Heart

•  Human heart is located inside the thoracic cavity, behind the breastbone & between the left and right lung

•  Cone-shaped and tilts slightly towards the left side of our body

•  Has a mass of about 300g & is built of thick and strong cardiac muscles

•  Entire heart is covered with a long lasting membrane

•  The space between the heart and the membrane is filled with fluid to reduce friction between the heart and other organs next to it Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.1 : Transport System in Human Detailed Structure of the Human Heart

•  There are four muscular chambers –  Left side : left

atrium, left ventricle

–  Right side : Right atrium, right ventricle

•  Septum separates the left and right chambers – WHY ?

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.1 : Transport System in Human Detailed Structure of the Human Heart

VENTRICLES •  Has a larger

volume of space than the atrium

•  Has a thicker wall than the atrium

•  Left ventricle is thicker and more muscular than the right ventricle – WHY ?

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.1 : Transport System in Human Detailed Structure of the Human Heart

•  Each ventricle & atrium is linked to one big blood vessel v Left atrium –

pulmonary vein v Right atrium –

vena cava v Left ventricle –

aorta v Right ventricle –

pulmonary artery

Pulmonary artery

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.1 : Transport System in Human Detailed Structure of the Human Heart

•  The one-way flow of blood in the heart is controlled by three types of valves v Bicuspid valve (mitra

valve) – controls blood from left atrium to left ventricle

v Tricuspid valve – controls blood from right atrium to right ventricle

v Semilunar valve – controls blood from ² left ventricle to

aorta ² right ventricle to

pulmonary artery

Bicuspid valve

Semilunar valve

Tricuspid valve

Semilunar valve

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.1 : Transport System in Human Functions of the Heart

Functions as a strong muscular pump to collect :- •  Deoxygenated

blood from the rest of the body – is pumped to the lungs

•  Oxygenated blood from the lungs – is pumped throughout the body

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.1 : Transport System in Human Functions of the Heart

Functions to circulate and transport :- •  Nutrients &

oxygen to the body cells

•  Excretory products (C02, urea & water) from the body cells to be removed from the body

Prepared  by  Ms  Sue  Soh  Ya  Lee  

Aorta  

Pulmonary  artery  

Pulmonary  veins  

Left  atrium  

Bicuspid  valve  

Left  ventricle  

Semilunar  valve  

Septum  Inferior  vena  cava  Right  ventricle  

Tricuspid  valve  

Right  atrium  

Pulmonary  veins  

Semilunar  valve  

Superior  Vena  cava  

From  le(  lung  

To  le(  lung  

From  body  

From  right  lung  

To  right  lung  

From  body  

To  body  

1 �

1 �2

3

4

5

6

67

8

9

10 �

11 �

12 �

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.1 : Transport System in Human Pathway of Blood Circulation

Vena cava

Right Atrium

Tricuspid valve

Right ventricle

Semilunar valve

Pulmonary artery Lungs

Pulmonary veins

Left atrium

Bicuspid valve

Left ventricle

Semilunar valve

Aorta (Whole body)

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.1 : Transport System in Human Types of Blood Vessels

•  Each blood vessel has lumen – the tract that allows blood to flow in the blood vessel

•  Lumen is important because the size of lumen affects the blood flow in the blood vessels –  Narrow lumen will be

an obstacle to the blood flow – blood flows faster & under high pressure

–  Wide lumen provides less resistance to the blood flow – blood flows more slowly & under low pressure Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.1 : Transport System in Human Types of Blood Vessels

•  There are 3 types of blood vessels : – Artery – Vein – Capillary

•  As blood is pumped out of the heart, it travels through arteries, veins and capillaries

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.1 : Transport System in Human Types of Blood Vessels

ARTERY •  Carries blood out of

the heart –  Aorta : artery that

carries blood from left ventricle of the heart

–  Pulmonary artery : artery that carries blood from the right ventricle to the lung

•  Carries oxygenated blood except pulmonary artery

•  Has narrow lumen Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.1 : Transport System in Human Types of Blood Vessels

ARTERY •  The artery wall is

thick, elastic and muscular to withstand high blood pressure

•  Arteries don’t have valves except pulmonary artery and aorta

•  Arteries which branch into smaller blood vessels are known as arterioles

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.1 : Transport System in Human Types of Blood Vessels

VEIN •  The blood vessel

that carries blood into the heart –  Vena cava :

transports blood to the right atrium of the heart

–  Pulmonary vein : transports blood from the lung to the left atrium

•  Transport deoxygenated blood except pulmonary vein

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.1 : Transport System in Human Types of Blood Vessels

VEIN •  Have wide lumen –

blood flow is slow and under low pressure

•  The wall is thin & less muscular

•  Have semilunar valves to ensure one-way of blood flow

•  Branch into smaller vessels called venules

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.1 : Transport System in Human Types of Blood Vessels

CAPILLARY •  Joins the artery to

the vein •  The narrowest

blood vessel •  Carries a

combination of oxygenated & deoxygenated blood

•  Its wall is very fine : one-celled thick – enables the exchange of gases & nutrients between blood & body cells

Vein  

Artery   Capillary  

Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.1 : Transport System in Human Types of Blood Vessels

CAPILLARY •  Blood flow is very slow and under low

pressure so that exchange of substance can take place more efficiently

•  Does not have any valves

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2.1 : Transport System in Human The Human Blood Ciculatory System

•  Heart is at the centre of the human circulatory system

•  Blood circulation in the body happens due to the pumping action of our heart

•  Human blood circulation is completed through 2 stages :- –  Pulmonary

circulation –  Systemic

circulation Prepared  by  Ms  Sue  Soh  Ya  Lee  

2.1 : Transport System in Human The Human Blood Ciculatory System

•  Both stages cause the blood to flow twice through the heart

•  Complete pulmonary circulation is the to-and-fro circulation from the heart to the lung

•  Pulmonary circulation alternates with the systemic circulation to complete the circulation around the body Prepared  by  Ms  Sue  Soh  Ya  Lee