transport in animals

Question 1

Why do large animals need a transport system?

Answer 1

• size
• level of metabolic activity
• sa:v as large animals have a smaller surface area to volume ratio

Question 2

What is a single circulatory system?

Answer 2

One in which blood flows through the heart once for each cycle of the body e.g. in fish

Question 3

What is a double circulatory system?

Answer 3

One in which the bloods flows through the heart twice for each circuit of the body

Question 4

What is an open circulatory system?

Answer 4

When blood is not contained in blood vessels but blood fluid circulates through the body cavity

Question 5

What are the disadvantages of an open circulatory system?

Answer 5

Blood pressure is low as it is not contained within blood vessels so blood flows slowly . in addition blood circulation may be effected by body movements or lack of movement

Question 6

What is a closed circulatory system?

Answer 6

when the blood is contained within a network of blood vessels

Question 7

What re the advantages of a double circulatory system?

Answer 7

high blood pressure so flow is quickermeanin git can provide a rapid delivery of 02 and nutrients

Question 8

What is the structure of the tunica intima?

Answer 8

Blood vessels consisting of three layers. The inner layer is called the tunica intimacy - made of endothelial layer, connective tissue and elastic fibres. the endothelium is one cell thick and lines the lumen, elastic allows it to stretch and recoil to maintain pressure

Question 9

What is the structure of the tunica media?

Answer 9

Made of a thick layer of smooth muscle which allows it to withstand high pressure and contract and narrow the lumenW

Question 10

What is the structure of the tunica adventitia?

Answer 10

consists of a thick layer of collagen and elastic tissues, collagen prevents overstretching.

Question 11

What are arterioles?

Answer 11

small blood vessels that dsitribute blood from an artery to the capillaries

Question 12

What are capillaries?

Answer 12

Thin walls to allows the exchange of materials between the blood and tissue fluid, have a narrow lumen the right size for RBCs

Question 13

What are venules?

Answer 13

Venules connect capillaries to the veins, have thin layers of muscle elastic and collagen because blood is at a low pressure.

Question 14

What are veins?

Answer 14

Carry blood to the heart, have thin walls and a larger lumen than arteries to ensure that blood is returned to the heart at an adequatenspeed , contain valves which are used to prevent the back flow of blood.

Question 15

What is tissue fluid?

Answer 15

The fluid surrounding tissues and cells which supplies them with oxygen and nutrients. It is formed when plasma leaks from the cappilaries.

Question 16

What is the tissue fluid formation process?

Answer 16

When an artery reaches the tissues it branches into arterioles and then to a network of capillaries which link up with venules that carry blood to veins.

At the arterial ends of the capillary is relatively high hydrostatic pressure which pushes fluid out the capillary walls . It surrounds body cells to allow exchange .

Question 17

How does tissue fluid return to the blood?

Answer 17

Blood pressure at the venous ends of the capillary is much lower which allows some of the tissue fluid to return to the capillary carrying waste products with it.w

Question 18

Where does excess tissue fluid that doesn’t enter the blood go?

Answer 18

Some is directed to the lymphatic system

Question 19

Describe blood entering the atrium

Answer 19

Deoxygenated blood from the body flows through the vena cave into the right atrium and oxygenated blood from the lungs flows through the pulmonary vein into the left atrium.

Question 20

How does blood move from the atrium to the ventricles?

Answer 20

From the atria the blood flows down through atria ventricular valves into ventricles. the valves have tendinous chords which are attached to prevent valves turning inside out when the ventricle walls contract

Question 21

What is the septum?

Answer 21

The septum operates the ventricles form each other to separate oxygenated and deoxygenated blood

Question 22

How does blood leave the ventricles?

Answer 22

Oxygenated blood leaves the left ventricles flows into the aorta which takes it to parts the body, and blood leaving the right ventricle flows into the pulmonary artery to the lungs.

Question 23

What is the cardiac cycle?

Answer 23

The sequence of events in one full beat of the heart.

Question 24

What is atrial systole?

Answer 24

Both right and left atria contract together, the muscles is thin so a small amount of pressure is created to push blood into the ventricles

Question 25

What is ventricular systole?

Answer 25

Both the right and left ventricles pump together, the ocontractions start at the base of the heart so blood is pushed up towards the arteries.

Question 26

What is diastole?

Answer 26

All walls of all heart chambers relax,

Question 27

What is the action of atrioventricular valves?

Answer 27

after atrial systole ventricular walls relax and recoil. pressure in the ventricles is below the pressure in the aorta is blood in the atria pushes the valves open so blood entering heart flows though atria into the ventricles causing atrial and ventricular pressure to uncrease

Question 28

What is the action of semilunar valves?

Answer 28

During ventricular systole pressure incresaes so the valves open, once walls have contracted diastole occurs so elastic tissue recoils and muscle stretches out.

Question 29

What 3 ways is carbon dioxide transported?

Answer 29

1. 5% dissolved in plasma
2. 10% combined with haemoglobin
3. 85% transported in the form of hydrogen carbonate ions

Question 30

How are hydrogen carbonate ions formed?

Answer 30

Co2 in blood plasma diffuses into blood cells which combines with water to form carbonic acid which is catalysed by the enzyme carbonic anhydrase.
carbonic acid dissociates to release H+ atoms and hydrogen carbonate ions which then diffuse out of red blood cells into the plasma. The change in RBCs acidity is maintained by Cl_ ions known as the chloride shift.

Question 31

What is the bohr effect?

Answer 31

describes the effect of increased carbon dioxide concentration on haemoglobin. Co2 enters the res blood cells to form acid and releases h+ios. The changes in pH of the cytoplasm mean the the tertiary structure of the haemoglobin is changed which reduces the affinity of oxygen wo it is unable to hold as much 02.

Question 32

How is oxygen transported?

Answer 32

Transported un the blood cells which contains haemoglobin.
haemoglobin + oxygen –> oxyhemoglobin.