Transport in Animals

Open or closed circulatory system

Open e.g. insects

Closed, e.g. Mammals, earthworms

Open or closed system

Open circulatory system

Closed circulatory system

Blood pressure

Direct contact with organs

Blood is contained in

Direction of circulation

Respiratory pigment

Transport of oxygen

Single circulation e.g. fish

Double circulation e.g. mammals

Closed Circulations: Single and Double

Define pulmonary circulation:

Define systemic circulation:

Advantages of Double Circulation

A double circulation has a number of advantages compared with a single circulation.

1. Maintains a high blood pressure in the systemic (body) circulation2. Allows for a lower pressure in the pulmonary (lung) circulation3. Circulation is faster in the systemic system than in the pulmonary

Explain these advantages:

4. In addition, the oxygenated and deoxygenated blood is kept separate

Why is this important?

Blood Vessels and the Circulation System

The transport system in mammals consists of a CLOSED, DOUBLE CIRCULATORY SYSTEM.

Blood vesselsThe 3 major types of blood vessels that make up the circulatory system are called:•

•

•

Label your diagram

Drawings of veins, arteries and capillaries (T.S.)

ARTERY

VEIN

CAPILLARY

Structure and Function of the Blood Vessels

Arteries and veins have the same three-layered structure, but the proportions of the different layers vary:

•Endothelium. This in the innermost layer of the vessel and is one cell thick. It provides a smooth lining.

Q.Why do you think this is an important feature?

•Elastic fibres and smooth muscle. These components make up the middle layer of the vessel. In arteries the layer is much thicker than in veins.

What is the function of smooth muscle in arteries?

What is the function of elastic fibres in arteries?

•Collagen Fibres. These fibres are found in the outer layer of the vessels and are resistant to over-stretching.

Veins have wider diameter lumens and walls than arteries, as the pressure and flow inside is much lower. The thin muscle layer in the walls can be compressed easily, allowing contracting ______________ muscle to squeeze veins and push the blood along. ___________ in the veins ensure that blood flows in one direction (towards the __________).

How the valves work

•Blood above the valve tries to flow back

•Blood fills the pockets

•This forces the valve shut

Arteries have a thick layer of ______________ _____________ and ____________ _______________.

Arterioles are able to adjust their diameter to vary the blood supply to a capillary bed.

Capillaries walls consist only of _________________ and are _______ ______ ___________. Some capillaries also have pores in their walls. Capillaries are permeable to water and dissolved substances such as glucose, amino acids, urea , _____________ and carbon dioxide.

The thin capillary walls allow for a more efficient exchange of materials and gases as there is a shorter diffusion _______________ and a larger cross-sectional ____________.

Capillaries have a narrow lumen, this restricts blood flow (blood is slowed down).

Comparing vessels

Feature Arteries Veins Capillary

Function

Walls

Lumen

Valves?

Blood pressure

Blood O2 concentration

The HeartThe heart is four chambered and consists largely of cardiac muscle. This is a specialised tissue that is capable of rhythmical contraction and relaxation over a long period without fatigue.

Label the main structures of the heart:

Give the function of the tendinous chords in the heart:

External Structure of the Heart

______

________

______

______

___

State the function of the main vessels of the heart

•Aorta

•Vena cavae

•Pulmonary arteries

•Pulmonary veins

•Coronary arteries

•Coronary veins

Blood flow through the heart and around the body

Lungs

Body tissues

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The Cardiac Cycle

The cardiac cycle is a continuous process, so a description of it could begin at any stage. Complete the description below:

1. The _________ relax, the left _______ receives oxygenated blood from the _______________ vein and the right ________ receives deoxygenated blood from the _______________ .

2. When the atria are full the pressure forces open the atrioventricular valves, _______________ in the left atria and ______________ in the right atria.

3. Blood is drawn from the atria into the _____________ which are ______________.

4. The __________ contract which forces the remaining blood into the ventricles.

5. The _____________ now contract, forcing the blood out via the __________________ valves through the ___________ artery and _____________.

Both ___________ contract together and both ___________ contract together. A single heartbeat is one single contraction ( ______________) and relaxation ( ______________ )

Why do you think the left ventricle has a thicker muscular wall than the right ventricle?

Pressure changes in the heart

1. The atrio-ventricular valves open when the pressure of the blood in the atria is greater than in the ventricles. They close when the pressure of the blood in the ventricles is greater than in the atria. Label the graph to show when the atrio-ventricular valves open and close.

2. The opening and closing of the semi lunar valves depends on the relative pressures in the aorta and pulmonary arteries and the ventricles. Label the graph to show when the semi lunar valves open and close.

3. For how long are the atrio-ventricular valves open?4. For how long are the semi lunar valves open?5. How long is does one heartbeat last?6. Calculate heart rate per minute:

ventriclearteryatrium

Artery Arterioles Capillaries Venules Veins

How blood pressure changes as it flows through the body.

1 2 3 4 5

1.

2.

3.

4.

5.

Control of Heartbeat