Circulatory System

Question 1

Functions of the circulatory system

Answer 1

> transport of substances
protection against disease
regulation of body temperature

Question 2

3 components that make up circulatory system

Answer 2

> the heart
blood vessels
the blood

Question 3

Substances transported by the blood

Answer 3

>oxygen (respiration)
>carbon dioxide (respiration)
>the products of digestion (glucose, amino acids, vitamins, minerals)
>urea (waste product from urine)
>hormones (adrenaline, insulin)

Question 4

By what processes are substances moved in and out of blood

Answer 4

> diffusion

>active transport

Question 5

3 major blood vessels

Answer 5

> arteries
veins
capillaries

Question 6

Arteries

Answer 6

Theses carry blood away from the heart

To accommodate high pressure they have the following features:
>thick outer wall with sub-layer or muscle and elastic fibres- this allows arteries to expand as blood flows through in a pulsatile way
>reduced diameter of the vessels lumen

Question 7

Veins

Answer 7

These carry blood back to the heart

> they have a small lumen as they are low pressure
contain valves- they guard against back-flow. They only open in one direction, if blood begins to flow backwards they are forced closed.

Question 8

Capillaries

Answer 8

These are responsible for exchange of substances

> they are one cell thick
gaps in between to minimise the diffusion distance
exchange of gases in the lungs and entry of nutrients to the blood both occur here

Question 9

Blood supply to organs

Answer 9

Each organ must receive blood for respiration and all will produce some sort of waste
To allow this:
>numerous arteries branch off the aorta to the organs of the body
>these vessels split up into smaller arteriolar and eventually into capillaries
>on leaving the organs the capillaries drain into veins
>the veins drain into the veins cava before returning to the heart

Question 10

Ventricles

Answer 10

The left ventricle is thicker than the right as it needs to generate greater to pressure to pump oxygenated blood to all the organs in the body.
The right ventricle only has to pump the blood to the lungs

Question 11

Double circulation

Answer 11

The right side of the heart pumps deoxygenate blood to the lungs to pick up oxygen.
The left is responsible for pumping oxygenated blood to all other organs.
To complete one lap of the body the blood has to travel through the heart twice

Question 12

Factors affecting heart rate

Answer 12

>gender
>diet
>body size
>stress
>size of heart
>injury
>fitness
>exercise

Question 13

Your pulse and heart rate

Answer 13

Pulse corresponds to the contraction of the left ventricle

-a reflection of the pulsatile flow through arterial system

Question 14

Athletes and their heart rate

Answer 14

The cardiac muscle reacts to exercise as other muscles do- the more they are used the larger they become
Athletes have a low resting heart rate (35bpm) as they have a larger heart
This means doesn’t have to contract so often as it holds a greater volume of blood

Question 15

Exercise and heart rate

Answer 15

Your heart rate and breathing increases this is because the demand of oxygen and fuel is increased for muscle tissue.
Blood has to be pumped to the cells more often to receive more oxygen and glucose for respiration

Question 16

Stress and heart rate

Answer 16

In times of stress the hormone adrenaline is released.

This has the effect of increasing heart rate in preparation for an event That will require more energy to be used

Question 17

What is tissue fluid?

Answer 17

On arrival to the capillary network the blood is under high pressure.

This factor combined with the leaky nature of the capillary wall forces plasma out of the capillaries into the space between the cells making up tissues.

This is known as tissue fluid and bathes all the cells of the body.

Question 18

Why is tissue fluid important

Answer 18

> It allows every cell to be supplied with the dissolved nutrients
it absorbs any waste materials produced by the cells

Question 19

Lymphatic system

Answer 19

This is the mechanism to remove tissue fluid (as it is constant) from tissues to prevent swelling.

The used tissue drains into the lymph vessels (fluid in vessels) and eventually returned to the main circulation (subclavian veins)

Question 20

Why does the right side of the heart appear on the left

Answer 20

Diagrams we use is like looking at someone in front of use/ mirroring image

Question 21

Why doesn’t the cardiac muscle tire?

Answer 21

With out the heart to circulate the blood organs wouldn’t receive the oxygen and glucose need for respiration to occur and we’d die.

Question 22

List of vessels the blood travels through

Answer 22

>pulmonary vein
>left atrium
>left ventricle
>aorta to the lower body
>vena cava
>right atrium
>right ventricle
>pulmonary arteries
>lungs

Question 23

Blood when resting

Answer 23

Blood flows into both sides of the heart when it’s resting between beats

Question 24

Exception to “arteries carry oxygenate blood and veins carry deoxygenated blood”

Answer 24

Pulmonary veins carries oxygenated blood

Pulmonary artery carries deoxygenated blood

Question 25

Which vessel is blood likely to be at its highest?

Answer 25

Aorta because it is closest to the left ventricle

Question 26

Why is fainting a safely mechanism

Answer 26

When standing the heart works over time to pump the blood from the lower body back to the heart to the brain. You faint so that gravity works with the heart so it doesn’t have to pump so hard

Question 27

Arterioles

Answer 27

Regulate blood flow/pressure to organs

Question 28

Atherosclerosis

Answer 28

This is furring up arteries by fatty substances. When this happens the blood flowing through the vessels is slowed down and target organs are not supplied with the nutrients and oxygen required to respire

Question 29

Cholesterol and heart attack

Answer 29

These fats are deposited on the blood vessels in area called plaque. This grows to a size where the vessel becomes blocked. If these happens in a coronary vessel a heart attack will occur.

Stress and sedentary lifestyle increases the risk

Question 30

Cholesterol and stroke

Answer 30

Cholesterol blocks a the vessel in the brain a stroke may occur

Question 31

Conditions increasing the risk of atherosclerosis

Answer 31

> high cholesterol

>smoking

Question 32

Smoking

Answer 32

Cigarette smoke contain toxins, some of which make the lining of the vessels more susceptible to fat being laid down.

Question 33

How to avoid atherosclerosis

Answer 33

> avoid fatty foods

>eat more foods rich in anti oxidants which can reverse it to a certain extent (fresh fruit and veg)

Question 34

How doctors prevent/minimise the growth of plaque and its effects

Answer 34

Insert tube into the vessel, this tube carries a deflated balloon. When the tube is passed to the point where the vessel is becoming furred the balloon can be inflated thereby compressing the deposit and keeping the vessels lumen open

Question 35

Catheterisation

Answer 35

To insert a more rigid stealth that will hold the vessel open or a tube can be inserted with a small cutting device that can remove the plaque completely

Question 36

Plaque making vessels rigid

Answer 36

If this happens in the arteries they are unable to accommodate the pulsing flow of blood. The vessel will burst and can lead to internal bleeding and sometimes death.