Circulatory System

Human Circulatory System• This is the transport system of the body and

has four main functions;

Human Circulatory SystemThis is the transport system of the body and has

four main functions; 1. Transportation of H2O, O2 and CO2

2. Distribution of nutrients (from digestion) and removal of wastes

3. Maintenance of body temperature (Vasoconstriction/Vasodilation)

4. Circulation of Hormones

What does the system need in order to meet all of it’s functions?

• Needs to be able to reach every cell in the body

• To distribute the necessary nutrients in a usable form

• Has to do all of this without disrupting the other systems in the body.

What does the system need in order to meet all of it’s functions?

• Needs to be able to reach every cell in the body- Arteries, Veins and capillaries stretch throughout the whole body in order to reach every cell.

• To distribute the necessary nutrients in a usable form- Blood is a fluid in which nutrients are supported.

• Has to do all of this without disrupting the other systems in the body- A pump (the heart) pushes the fluid (the blood) through the body (arteries, veins and blood vessels) without affecting other systems

Circulatory VS Cardiovascular• On your own, you have two minutes to find

the difference between the Circulatory system and the Cardiovascular system.

• What each system does, what parts of the body are involved, how they may overlap?

Put these into a Glossary page• Circulatory-A system that circulates blood

throughout the body, consisting of the heart and blood vessels as well as the lungs.

• Cardiovascular- System that involves the heart and blood vessels

What is blood?

• Red Blood cells• White blood cells• Plasma• Platelets

Plasma

• 55% of blood by volume is plasma of that 91% is water, the remainder largely consists of dissolved protein

• Plasma suspends red blood cells• Buffers the Ph of blood• Promotes clotting

White blood cells

• Less than 1/10th of 1% of blood by volume• Destroy foreign cells• Remove debris• Immune response• Life is variable, shorter if infection is present

Red blood cells

• 45% of blood is red blood cells

Red blood cells

• Transport oxygen via haemoglobin• Haemoglobin is a protein containing iron

which oxidises in the presence of oxygen• Therefore oxygenated blood is red• Have no nuclei• Last for 120 days• Produced in the bone marrow

Platelets

• Less than 1/100th of 1% of blood by volume• Clump together to block holes in blood vessels• Platelets membranes break releasing clotting

factors• Converts soluble protein to insoluble fibrin• Causes blood cells to stick together• Live about 1 week

Blood disorders

• Leukaemia; high numbers of white blood cells• Anaemia; too few red blood cells• Polycythemia; too many red blood cells• Haemophilia; deficiency in clotting agents

• Carbon Monoxide Poisoning-

Glossary• Red Blood cells (erythrocytes)- Transport Oxygen

around the body via haemoglobin, have no nucleus, large % of blood is RBC (45%).

• White blood cells (leukocytes)- Protect the body against micro-organisms and toxins and contains a nucleus. Involved in the immune response.

• Plasma-Liquid component of blood, • Platelets- Blood clotting agent. 1/100th of 1%

(.01%) of blood by volume.

Concept!• Blood is the fluid of the circulatory system. It is

essential to life. • It consists of a solid part, the cells, and the

liquid part, plasma. • Blood carries oxygen and nutrients to and

from the cells via arteries, veins and capillaries.

The Heart

The Heart• The heart is a two sided, four chambered

pump. • It is made up mostly of muscle. • Unlike all the other muscles in the body, the

heart muscle cannot afford to get tired....Why?

The Heart1. The heart is the size of a fist. 2. It is made of a very strong muscle. 3. The heart is divided into four chambers: right

atrium, right ventricle, left atrium, left ventricle. 4. A series of valves open to allow blood flow

from one chamber to the next. 5. A muscle wall called the septum separates the

left and right side of the heart

Functions1. It contracts sending

oxygen-rich blood to the tissues and oxygen-poor blood to the lungs.

2. The nervous system controls heart beat and tissue known as the pacemaker also controls heart beat.

Glossary

• Heart- The heart is divided into four chambers: right atrium, right ventricle, left atrium, left ventricle. It acts as a pump to move blood and nutrients around the body

YouTube Clip

• Circulatory Systemhttp://www.youtube.com/watch?v=D3ZDJgFDdk0

Getting the Blood around the body

• How do we do this? What is involved?• There are three varieties of blood vessels:

arteries, veins, and capillaries. • During blood circulation, the arteries carry

blood away from the heart. • The capillaries connect the arteries to veins.

Finally, the veins carry the blood back to the heart.

A VERY VERY long system• If you took all of the blood vessels out of an

average child, and laid them out in one line, the line would be over 96,000 km long!

• An adult's vessels would be closer to 160,000 km long

Glossary• Aorta- the largest artery leading out of the left

ventricle to the rest of the body.

• Vena Cava- The main veins that receive blood from the rest of the body.– Inferior: Drains lower body– Superior : Drains head and arms.

Arteries• Carry oxygenated blood away

from the heart• An artery has three layers:

– an outer layer of tissue, – a muscular middle, – and an inner layer of epithelial

cells. • The muscular wall of the

artery helps the heart pump the blood.

Capillaries• The capillaries are one epithelial

cell thick. RBC only pass through them in single file.

• The exchange of oxygen and carbon dioxide takes place through the thin capillary wall.

• The tissue releases its waste products, like carbon dioxide, which pass through the wall and into the red blood cells.

Veins• Veins are similar to arteries but

transport blood at a lower pressure.• Veins have three layers:

– an outer layer of tissue, – muscle in the middle, – and a smooth inner layer of epithelial cells.

However, the layers are thinner, containing less tissue.

• Receive waste-rich blood from capillaries and take it back to the lungs and heart.

• Valves are like gates that only allow blood to move in one direction.

Valves

Glossary• Arteries- Are thick walled blood vessels that

transport oxygenated blood from the heart to the body

• Capillaries- blood vessels that connect the arteries to tissues, then tissues to the veins. Very thin, only 1 RBC thick.

• Veins- blood vessels with thinner walls and valves that take blood to the heart.

• Valves- allow blood flow in one direction only.

Getting Oxygen into the Blood Stream1. Air Passes into the lungs through the nose and mouth

3. Trachea branches into two bronchi, which lead to the lungs

4. Each bronchus divides into smaller tubes called Bronchioles.

5. Each bronchiole ends in a cluster of tiny air sacs called alveoli

2. Travels past the throat and larynx into the trachea

Getting Oxygen into the Blood stream6. Gas exchange occurs at the Alveoli. 700 million alveoli in the lungs give a surface area of approximately the size of a tennis court.

7. Each alveolus has a network of capillaries around it.

9. The distance between the alveolar and a RBC is less than 1 micrometre, so gas exchange is very easy.

8. The thin wall of the alveolar cell and the one cell thick capillary wall separate the two.

Controlling Breathing• Note. Breathing is

controlled by the movements of the ribs and the diaphragm.

-Inhalation; Muscles lift ribs upwards and outwards

-while the muscular diaphragm contracts and moves downwards.

-This increases the volume of the chest cavity

Controlling Breathing• The reverse happens

for exhalation– Ribs come

downwards and inwards

– Diaphragm expands and moves upwards

– Decreasing volume of chest cavity

Pulmonary vein

Right atrium

Right ventricle

Posteriorvena cava Capillaries of

abdominal organsand hind limbs

Aorta

Left ventricle

Left atrium

Pulmonary vein

Pulmonaryartery

Capillariesof left lung

Capillaries ofhead and forelimbs

Anteriorvena cava

Pulmonaryartery

Capillariesof right lung

Aorta

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YouTube• Circulatory Songhttp://www.youtube.com/watch?v=q0s-1MC1hcE