CHAPTER 2 : BLOOD CIRCULATION & TRANSPORT2.1 : Transport
System in Human
2.2 : Human blood2.3 : Transport
System in Plants
2.1 : Transport System in HumanGeneral 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
2.1 : Transport System in HumanDetailed 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 ?
2.1 : Transport System in HumanDetailed 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 ?
2.1 : Transport System in HumanDetailed Structure of the Human Heart
Each ventricle & atrium is linked to one big blood vesselvLeft atrium
pulmonary veinvRight atrium
vena cavavLeft ventricle
aortavRight ventricle
pulmonary artery
Pulmonary artery
2.1 : Transport System in HumanDetailed Structure of the Human Heart
The one-way flow of blood in the heart is controlled by three types of valvesvBicuspid valve (mitra
valve) controls blood from left atrium to left ventricle
vTricuspid valve controls blood from right atrium to right ventricle
vSemilunar valve controls blood fromleft ventricle to
aortaright ventricle to
pulmonary artery
Bicuspid valve
Semilunar valve
Tricuspid valve
Semilunar valve
2.1 : Transport System in HumanFunctions 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
2.1 : Transport System in HumanFunctions 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
Aorta
Pulmonary artery
Pulmonary veins
Left atrium
Bicuspid valve
Left ventricle
Semilunar valve
Septum
Aorta
Right ventricle
Tricuspid valve
Right atrium
Pulmonary veins
Semilunar valve
Vena cava
From le( lung
To le( lung
To body
From right lung
To right lung
From body
To body
1
1 2
3
4
5
6
67
8
9
10
11
12
2.1 : Transport System in HumanPathway 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)
2.1 : Transport System in HumanTypes 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
2.1 : Transport System in HumanTypes of Blood Vessels
There are 3 types of blood vessels :ArteryVeinCapillary
As blood is pumped out of the heart, it travels through arteries, veins and capillaries
2.1 : Transport System in HumanTypes 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
2.1 : Transport System in HumanTypes of Blood Vessels
ARTERY The artery wall is
thick, elastic and muscular to withstand high blood pressure
Arteries dont have valves except pulmonary artery and aorta
Arteries which branch into smaller blood vessels are known as arterioles
2.1 : Transport System in HumanTypes 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
2.1 : Transport System in HumanTypes 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
2.1 : Transport System in HumanTypes 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
2.1 : Transport System in HumanTypes 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
2.1 : Transport System in HumanThe 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
2.1 : Transport System in HumanThe 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