Blood Circulatory System

3.2  Blood Circulatory System

 

Definition

A tubular system that has pumps and valves that consist of three components, namely the heart, blood vessels, and blood to ensure blood flow occurs in one direction only

 The circulatory system for 3 classes of vertebrates:

 

The structure and function of the human heart:

 

Structure

Function

Left atrium

Pumping oxygenated blood to the left ventricle

Right atrium

Pumping deoxygenated blood to the right ventricle

Left ventricle

Pumps blood to all parts of the body except the lungs

Right ventricle

Pumping deoxygenated blood from the heart to the lungs

Vena cava

Carries deoxygenated blood from the rest of the body to the right atrium

Pulmonary artery

Carries deoxygenated blood from the right ventricle to the lungs

Aorta

Carries oxygenated blood from the left ventricle to all parts of the body (largest artery)

Pulmonary vein

Carries oxygenated blood from the lungs to the left atrium

Septum

Isolate the left chamber and the right chamber of the heart

Tricuspid valve

Prevents the recirculation of blood from the right ventricle to the right atrium during ventricular contraction

Bicuspid valve

Prevents the re-flow of blood into the left ventricle from the left atrium during ventricular contraction

Sickle valve

Prevents the re-flow of blood to the ventricles when the ventricles relax

 The functional efficiency of the human heart:

  • The heart wall is built of cardiac muscle that can contract and relax rhythmically

  • The ventricle has a thicker wall and contracts more strongly than the atrium

  • Has a valve that keeps the blood flowing in one direction only

  • Has a septum that ensures oxygenated blood and deoxygenated blood do not mix

The structure and function of human blood vessels:

 

Types of blood vessels

Vena

Function

Brings blood to the heart

Lumen size

Big

Wall thickness

- Thin

- Less muscular

- Less elastic

Valve

There is

Blood flow

Slow and under very low pressure

Type of blood transported

The blood is deoxygenated except the pulmonary veins

Types of blood vessels

Blood capillaries

Function

- Connecting arteries and veins

- Allows the exchange of substances between the blood and body cells

Lumen size

Very small

Wall thickness

The wall is one cell thick

Valve

None

Blood flow

Very slow and under very low pressure

Type of blood transported

Both types of blood is oxygenated and deoxygenated

Types of blood vessels

Artery

Function

Bringing blood out of the heart

Lumen size

Small

Wall thickness

- Thick

- Muscular

- Elastic

Valve

None

Blood flow

Fast and under very high pressure

Type of blood transported

Oxygenated blood except for pulmonary arteries

The human circulatory system:

  • The human circulatory system is a closed tubular system that is pumped throughout the body

  • Double circulatory system

  • Pulmonary circulation - blood is transported from the heart to the lungs and back to the heart

  • Systemic circulation - blood is transported from the heart to other parts of the body (except the lungs) and back to the heart

The blood pressure:

  • The pressure exerted on the walls of blood vessels due to blood circulation

  • Two readings, namely systolic reading (upper number) and diastolic reading (lower number)

 

Systolic readings

Diastolic readings

Low blood pressure

Under 90

Under 60

Normal

90 - 120 mmHg

60 - 80 mmHg

Pre high blood pressure

120 - 139 mmHg

80 - 89 mmHg

High blood pressure

140 - 160 mmHg

90 - 100 mmHg

 The systole and diastole:

  • When the heart beats, there are two phases namely the diastolic phase and the systolic phase

  • Diastolic phase - the ventricles relax and blood fills the ventricles

  • Systolic phase - the ventricles contract and blood fills the ventricles

  • Lub dub sounds result from closed tricuspid and bicuspid valves (lub) and closed sickle valves (dub)

The factors that affect the heart rate:

Gender

Females have higher pulse rates than males due to small body size and less muscle mass

Age

The normal pulse rate for adolescents at rest is 75/min and lower for the elderly

Health rates

Healthy individuals have low pulse rates at rest

Activity fitness

During vigorous activity, the pulse rate increases

The cardiac care measures:

  • Reduce salt and sugar in food

  • Control blood pressure and diabetes

  • Exercise regularly at least five times a week

  • Eat vegetables and fruits

Blood Circulatory System

3.2  Blood Circulatory System

 

Definition

A tubular system that has pumps and valves that consist of three components, namely the heart, blood vessels, and blood to ensure blood flow occurs in one direction only

 The circulatory system for 3 classes of vertebrates:

 

The structure and function of the human heart:

 

Structure

Function

Left atrium

Pumping oxygenated blood to the left ventricle

Right atrium

Pumping deoxygenated blood to the right ventricle

Left ventricle

Pumps blood to all parts of the body except the lungs

Right ventricle

Pumping deoxygenated blood from the heart to the lungs

Vena cava

Carries deoxygenated blood from the rest of the body to the right atrium

Pulmonary artery

Carries deoxygenated blood from the right ventricle to the lungs

Aorta

Carries oxygenated blood from the left ventricle to all parts of the body (largest artery)

Pulmonary vein

Carries oxygenated blood from the lungs to the left atrium

Septum

Isolate the left chamber and the right chamber of the heart

Tricuspid valve

Prevents the recirculation of blood from the right ventricle to the right atrium during ventricular contraction

Bicuspid valve

Prevents the re-flow of blood into the left ventricle from the left atrium during ventricular contraction

Sickle valve

Prevents the re-flow of blood to the ventricles when the ventricles relax

 The functional efficiency of the human heart:

  • The heart wall is built of cardiac muscle that can contract and relax rhythmically

  • The ventricle has a thicker wall and contracts more strongly than the atrium

  • Has a valve that keeps the blood flowing in one direction only

  • Has a septum that ensures oxygenated blood and deoxygenated blood do not mix

The structure and function of human blood vessels:

 

Types of blood vessels

Vena

Function

Brings blood to the heart

Lumen size

Big

Wall thickness

- Thin

- Less muscular

- Less elastic

Valve

There is

Blood flow

Slow and under very low pressure

Type of blood transported

The blood is deoxygenated except the pulmonary veins

Types of blood vessels

Blood capillaries

Function

- Connecting arteries and veins

- Allows the exchange of substances between the blood and body cells

Lumen size

Very small

Wall thickness

The wall is one cell thick

Valve

None

Blood flow

Very slow and under very low pressure

Type of blood transported

Both types of blood is oxygenated and deoxygenated

Types of blood vessels

Artery

Function

Bringing blood out of the heart

Lumen size

Small

Wall thickness

- Thick

- Muscular

- Elastic

Valve

None

Blood flow

Fast and under very high pressure

Type of blood transported

Oxygenated blood except for pulmonary arteries

The human circulatory system:

  • The human circulatory system is a closed tubular system that is pumped throughout the body

  • Double circulatory system

  • Pulmonary circulation - blood is transported from the heart to the lungs and back to the heart

  • Systemic circulation - blood is transported from the heart to other parts of the body (except the lungs) and back to the heart

The blood pressure:

  • The pressure exerted on the walls of blood vessels due to blood circulation

  • Two readings, namely systolic reading (upper number) and diastolic reading (lower number)

 

Systolic readings

Diastolic readings

Low blood pressure

Under 90

Under 60

Normal

90 - 120 mmHg

60 - 80 mmHg

Pre high blood pressure

120 - 139 mmHg

80 - 89 mmHg

High blood pressure

140 - 160 mmHg

90 - 100 mmHg

 The systole and diastole:

  • When the heart beats, there are two phases namely the diastolic phase and the systolic phase

  • Diastolic phase - the ventricles relax and blood fills the ventricles

  • Systolic phase - the ventricles contract and blood fills the ventricles

  • Lub dub sounds result from closed tricuspid and bicuspid valves (lub) and closed sickle valves (dub)

The factors that affect the heart rate:

Gender

Females have higher pulse rates than males due to small body size and less muscle mass

Age

The normal pulse rate for adolescents at rest is 75/min and lower for the elderly

Health rates

Healthy individuals have low pulse rates at rest

Activity fitness

During vigorous activity, the pulse rate increases

The cardiac care measures:

  • Reduce salt and sugar in food

  • Control blood pressure and diabetes

  • Exercise regularly at least five times a week

  • Eat vegetables and fruits