UNIT A: MAINTAINING HEALTH: CIRCULATION AND IMMUNITY
CHAPTER 1: CIRCULATORY SYSTEM
➢ Cardiac Output Calculation
• Cardiac Output: the volume of blood pumped by the heart in one minute, which is
equal to the product of stroke volume and heart rate
• Cardiac Output (ml/min) = Stroke Volume (ml/beat) x Heart Rate (beats/min)
➢ Anatomy of the heart
o Vena Cava: either superior or inferior vena cavae, delivers oxygen-depleted blood to the
ride side of the heart
o Right/Left Ventricle: the larger V-shaped bottom chamber that pumps blood from the
heart
o Right/Left Atrium: the smaller upper chamber that receives blood returning to the heart
o Pulmonary Artery: carry blood with relatively low oxygen content and high carbon
dioxide content into the lungs
o Pulmonary Vein: receive oxygenated blood from the lungs and delivering it to the left
atrium, where it can then enter the left ventricle to be circulated throughout the body.
▪ Only vein that carries oxygenated blood
o Coronary Artery: the vessels that supply the heart muscle with oxygen-rich blood
o Aorta: is the largest artery in the body. The heart pumps blood from the left ventricle
into the aorta through the aortic valve.
o Heart Valves: thin flaps of tissue in the heart that open and close to ensure the proper
direction of blood flow
, ➢ Difference between veins, arteries, and capillaries
# Arteries Veins Capillaries
1 Responsible for the Collect blood through Connect arteries and veins
transportation of blood capillaries and transport it
from the heart to all parts towards the heart
of the body
2 All arteries carry All veins carry These carry mixed
oxygenated blood except deoxygenated blood oxygenated and
pulmonary arteries which except the pulmonary deoxygenated blood
carry deoxygenated blood veins which carry
oxygenated blood
3 Arteries have no valves in Valves are present in There are no valves in
them except at the base of veins. These valves capillaries
the pulmonary trunk and prevent the backflow of
aorta blood.
4 Arteries have high blood Veins have low blood There is falling pressure in
pressure pressure them
5 In arteries, waves of blood There is no pulse There is no pulse
pressure or pulse due to
heartbeat can be detected
6 Blood flows rapidly The rate of blood flow Blood flow is slowest
between 400-500mm per increases from smaller to which is less than 1mm
second in the aorta and larger veins per second
decreasing in the arteries
and arterioles
7 Arteries have a smaller Veins have a larger bore Capillaries have a larger
bore and thick walls and thin walls bore and the wall is of one
cell in thickness
8 There are thick muscular There are thin muscle No muscles are elastic
layers and elastic fibres layer and less elastic fibres fibres are present.
present. The elasticity present in veins.
helps to change the
pulsating flow of blood.
9 There is no exchange of There is no exchange of These are responsible for
materials. materials. the exchange of gases and
nutrients.
CHAPTER 1: CIRCULATORY SYSTEM
➢ Cardiac Output Calculation
• Cardiac Output: the volume of blood pumped by the heart in one minute, which is
equal to the product of stroke volume and heart rate
• Cardiac Output (ml/min) = Stroke Volume (ml/beat) x Heart Rate (beats/min)
➢ Anatomy of the heart
o Vena Cava: either superior or inferior vena cavae, delivers oxygen-depleted blood to the
ride side of the heart
o Right/Left Ventricle: the larger V-shaped bottom chamber that pumps blood from the
heart
o Right/Left Atrium: the smaller upper chamber that receives blood returning to the heart
o Pulmonary Artery: carry blood with relatively low oxygen content and high carbon
dioxide content into the lungs
o Pulmonary Vein: receive oxygenated blood from the lungs and delivering it to the left
atrium, where it can then enter the left ventricle to be circulated throughout the body.
▪ Only vein that carries oxygenated blood
o Coronary Artery: the vessels that supply the heart muscle with oxygen-rich blood
o Aorta: is the largest artery in the body. The heart pumps blood from the left ventricle
into the aorta through the aortic valve.
o Heart Valves: thin flaps of tissue in the heart that open and close to ensure the proper
direction of blood flow
, ➢ Difference between veins, arteries, and capillaries
# Arteries Veins Capillaries
1 Responsible for the Collect blood through Connect arteries and veins
transportation of blood capillaries and transport it
from the heart to all parts towards the heart
of the body
2 All arteries carry All veins carry These carry mixed
oxygenated blood except deoxygenated blood oxygenated and
pulmonary arteries which except the pulmonary deoxygenated blood
carry deoxygenated blood veins which carry
oxygenated blood
3 Arteries have no valves in Valves are present in There are no valves in
them except at the base of veins. These valves capillaries
the pulmonary trunk and prevent the backflow of
aorta blood.
4 Arteries have high blood Veins have low blood There is falling pressure in
pressure pressure them
5 In arteries, waves of blood There is no pulse There is no pulse
pressure or pulse due to
heartbeat can be detected
6 Blood flows rapidly The rate of blood flow Blood flow is slowest
between 400-500mm per increases from smaller to which is less than 1mm
second in the aorta and larger veins per second
decreasing in the arteries
and arterioles
7 Arteries have a smaller Veins have a larger bore Capillaries have a larger
bore and thick walls and thin walls bore and the wall is of one
cell in thickness
8 There are thick muscular There are thin muscle No muscles are elastic
layers and elastic fibres layer and less elastic fibres fibres are present.
present. The elasticity present in veins.
helps to change the
pulsating flow of blood.
9 There is no exchange of There is no exchange of These are responsible for
materials. materials. the exchange of gases and
nutrients.
