Organisational Complexity of the Human

Circulation System

You need to know……

Lymphatic system ABO blood groups

Composition of blood Rhesus Factor Blood pressure

Pulse

Coronary arteries & veins supplying the heart muscle

Role of muscle and valves in heart and blood vessels

Structure of the heart & path of blood path through it

Pulmonary & systemic circulation and portal systems

Arteries, arterioles, veins, venules and capillaries

The way a closed circulation system is organised

Two types of Circulation System

Heart pumps blood into vessels that are open ended ……eg in Insects

Blood remains in a continuous system of blood vessels…..eg in Humans

Open Circulation Systems

Closed Circulation Systems

Advantages of a Closed Circulation System

1. Blood can be pumped faster

2. Blood flow rate to different organs can be changed

Therefore nutrients can be delivered faster to cells allowing the organism to be more active

For example blood flow can be increased to the leg mucles when running

Main parts of Human Circulation System

1. Heart

2 Blood Vessels

Arteries

3. Blood

Veins

Capillaries

Arterioles

Venules

Main Blood VesselsArteries

Veins

Carry blood away from the heart

Carry blood under high pressure

Thick elastic wall

Narrow lumen

Carry blood towards the heart

Carry blood under low pressure

Have valves to prevent backflow

Thin wall

Wide lumen

Smaller Blood vessels

Arterioles

Venules

Arterioles connect arteries and capillaries

venules connect capillaries to the veins

Capillaries

The thin wall allows easy exchange of materials with cells

Tiny blood vessels linking arterioles and venules

Blood vessels under the microscope

Thick Wall

Arteries Veins

Narrow lumen

Thin Wall

Wide lumen

Have valves to prevent backflow

Collagen

Muscle andElastic fibres

Endothelium

Lumen

1 Give three differences between arteries and veins

2 What is the function of valves in veins

3 Name the blood vessels that connect capillaries and veins

4 Give one advantage of a closed circulation system

Muscle expand to allow increased blood flow through the vessel

Elastic fibres bring the blood vessel back to shape

Valves prevent backflow

Location Between the lungs, slightly to the left side of the thorax, above the diaphragm

Function To pump blood around the body

StructureA hollow structure made of cardiac muscle, surrounded by a double membrane

Role of Heart Muscle

1. The heart wall is made of Cardiac Muscle

2. Contraction of the cardiac muscle drives blood around the body

3. Cardiac Muscle does not fatigue

Human Two-Circuit Circulation

Pulmonary Circuit

Systemic Circuit

Pumps to the head, trunk and limbs and back to the heart

Pumps to the lungs and back to the heart

Advantages of a Double Circulation System

1. Separation of oxygen rich and oxygen poor blood

2. Blood pressure can be kept high

Pathway of blood Around Body

Portal systems

Hepatic Portal System

A blood pathway that begins and ends in capillaries

Connects the stomach and intestines with the liver

1 Name the blood vessel that connects the digestive system with the liver

2 Distinguish between the systemic the pulmonary blood circuits

3 Give one advantage of a double circulation system

Vena Cava

Right Atrium

Tricuspid Valve

Right ventricle

Left Ventricle

Left Atrium

Pulmonary Vein

Aorta

Pulmonary Artery

Bicuspid Valve

Septum

Cardiac muscle

Semi Lunar Valves

Blood pathway through heart

Right Atrium

Tricuspid valve

Right ventricle

Left atrium

Bicuspid valve

Left ventricle

Vena Cava

Pulmonary arteryAorta

Pulmonary vein

Role of Valves

Semi Lunar valves

Tricuspid valve

Bicuspid Valve

Prevent backflow into heart

Prevents backflow into left atrium

Prevents backflow into right atrium

Blood supply to the heart wall

Coronary arteries

Cardiac muscle is supplied with blood by the coronary arteries. These branch from the aorta just above the semi lunar valves ot the aorta

Coronary veins

Drain blood from heart wall into the right atrium

1 Where does blood go immediately after leaving the right ventricle ?

2 Name the blood vessel that enters the right atrium

3 What is the function of the coronary arteries ?

4 State the exact location of the opening into the coronary arteries

2 Name the valve between the left atrium and left ventricle

( Higher level material on heartbeat control in section 3.2.4 )

The heart beat consists of alternate contraction and relaxation of the cardiac muscle

The heart beat is controlled by the pacemaker in the right atrium. This sends an electrical signal to the cardiac muscle

The heart beat sound is caused by the closing of the heart valves

Pulse

A wave of expansion passes down the walls of arteries following a contraction of the left ventricle. The elastic fibres in the artery walls then bring about a contraction of the artery wall.

Average pulse rate is 72 beats per minute

The alternate expansion and contraction of arteries is called a pulse

Blood Pressure

As blood passes from arteries to veins pressure drops

Blood pressure is measured with an instrument that records the pressure it takes to stop the blood flow in an artery of the upper arm

Pressure in the due the to contraction of the ventricles which forces blood into the arteries

Effect of smoking on the circulation system

2. CO2 reduces the amount of O2 carried by the blood

1. Nicotine increases the heart rate and blood pressure

These puts a bigger workload on the heart

This reduces energy levels

3. Other chemicals in tobacco

Increase the chance of clots

Effect of Diet on the circulation system

High salt intake

High intake of fat causes a build up of cholesterol

Cholesterol may block arterioles and lead to stroke or heart attack

Raises blood pressure which can cause heart attack

Effect of Exercise on the circulation system

Exercise increases our ability to transport oxygen

Exersise strengthens the heart

This improves circulation

This gives increased energy levels

1 What causes the blood to be under pressure in the arteries ?

2 Explain the term Pulse

3 What controls the rate of heartbeat

4 Give two harmful effects of cigarette smoke on the circulation system

5 Explain why salt can have a negative effect on the circulation system

Lymphatic System

A secondary transport system consisting of one way system of vessels that collects and returns excess tissue fluid to blood system

1. Lymph vessels

2. Lymph Nodes

3. Lymph

Structure

Lymphatic System Functions

1. Collect tissue fluid and return it to the blood system

2. Fight Infection by

3. Transport digested fat away from intestine

(a) Filtering out microorganisms in the lymph nodes

(b) Destroying microorganisms by antibody production

(c) Mature and store lymphocytes

Plasma Liquid part of the blood

Red Blood Cells

White Blood Cells

Platelets

Composed of mainly water which acts as a transport medium for the cells and dissolved substances

Plasma

Red Blood Cells

White Blood Cells

Platelets

Carry Oxygen

Fight Infection

Clotting

Higher level

material in sec 3.2.3

Composed of mainly water which as a transport medium for the cells and dissolved substances

Digestion products ….Glucose, amno acids, Fatty acids, glycerol, minerals and vitamins

Waste….Carbon dioxide, urea

Hormones….eg Insulin

Antibodies

It is essential to know a persons blood group for safe blood transfusions

A

B

AB

O

Group

Another blood grouping system

Involvs antigen called factor D on the red cells

If you have factor D you are Rhesus positive or Rh+

If you haven’t you are Rhesus negative or Rh-

Rhesus factor is important in pregnancy as problems may arise in second and further pregancies if the mother is

Rh - and the baby is Rh +

1 Name the three main parts of the Lymphatic System

2 Name three substances dissolved in plasma

3 Name a blood grouping system other than the ABO System

4 What is the function of white blood cells

5 Give two functions of the Lymphatic System

See PowerPoint in section 3.2.3 for for higher level material on blood cells

See PowerPoint in section 3.2.4 for higher level material on heartbeat control