Transport in Animals M3 Flashcards Preview

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Flashcards in Transport in Animals M3 Deck (17)
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1
Q

Explain and compare the circulatory systems of a fish and a mammal.

A

Fish - a heart, with one ventricle and atrium, closed single system, lower metabolic rate, ectotherms. Mammals - a heart with two ventricles and two atria. Close double circulatory system, blood is pumped faster at a higher pressure

2
Q

Compare a closed and open circulatory system.

A

Closed, blood is carried in vessels where gases can be exchanged (fish/mammals) Supports high metabolic processes, more effective at transport blood all around the body. Open, means they don’t have veins and the blood flows freely through the cavities of the body and blood comes in direct contact with cells, where exchange happens.. (insects)

3
Q

What are the main reasons that make a transport system necessary in an animal?

A
  1. cells need oxygen + nutrients and to remove CO2. 2. diffusion pathway is large so diffusion is to slow. 3. With larger animals, their SA:V ration decrease and their so demand for oxygen + nutrients are greater than possible supply. 4. As activity increase, metabolic rate increase, need for O2 + nutrients increases and high oxygen demand can not be met with diffusion alone. 5. land animals are to dry for diffusion, need a moist surface,
4
Q

How do capillary networks change pressure and blood flow rate

A

slows blood down and it provides resistance so that diffusion can occur.

5
Q

Suggest why insects can have an open circulatory system but not mammals.

A

The blood in insects does not carry oxygen to the tissues or collect carbon dioxide because the system of tracheae and tracheoles carries out this function.
Therefore there is no need for a highly efficient circulatory system.
In mammals, blood must deliver oxygen efficiently to the tissues and remove CO2 as well as glucose.

6
Q

Explain Diastole

A

The ventricle walls relax and the pressure in the ventricles falls. Blood starts to flow from the atria into the ventricles again. Atrial pressure is higher than the ventricular.

7
Q

Explain Atrial systole

A

The walls of the atria contract. This reduces the volume of the atria, increasing the pressure. More blood passes through the already open atrioventricular valves into the ventricles.

8
Q

Explain ventricular systole

A

The walls of the ventricles now contract, reducing the volume in the ventricles. The pressure increases and blood is forced into the arteries. Atria walls relax and starting to fill again

9
Q

Describe the layers in blood vessels.

A

TUNICA EXTERNA - a thick layer of COLLAGEN gives strength to the wall so it can WITHSTAND high pressures. TUNICA MEDIA - Eklastic fibres STRETCH when the hearts in systole and RECOILS when its in diastole to MAINTAIN pressure.

10
Q

Why are arterioles important?

A

Control distributions of blood, by vasoconstriction and vasodilation, so they have a high proportion of smooth muscle

11
Q

How are veins adapted to their function

A

Blood pressure is low, so walls are thin and valves help maintain blood flow in the right direction

12
Q

How are capillaries adapted to their function?

A
  1. one cell thick endothelium makes a short diffusion pathway for blood. 2. large SA for diffusion 3. permeable to gases, water and solutes. 4. narrow lumen offers resistance to flow giving time for diffusion to take place. 5.
13
Q

Describe and explain how tissue fluid is formed and reabsorbed as blood flows along a capillary …6 marks

A

At the ARTERIOLE END of the capillary, the HYDROSTATIC PRESSURE is high
It is greater than the force created by water potential-(ONCOTIC POTENTIAL) so fluid (water and solutes) are forced out through the gaps in the capillary.
PLASMA PROTEINS and cells are too large to leave the capillary and produce high oncotic pressure and low water potential.
At the VENULE END of the capillary, the oncotic pressure is now HIGHER THAN the hydrostatic pressure, so water returns into the capillary by OSMOSIS, down a water potential gradient.
Some TISSUE FLUID is absorbed into LYMPH VESSELS.

14
Q

Where does loading take place?

A

the capillaries in the lungs, where there is lots of oxygen. Oxygen combines with haemoglobin to form oxyhemoglobin

15
Q

Where does unloading take place?

A

the capillaries of the tissues where the partial pressure of oxygen is low (ppO2). Oxygen dissociates from haemoglobin.

16
Q

key points that cause the Bohr shift/effect.

A
  1. muscle contraction causes respiration rate to go up. 2. More CO2 is produced by tissues/muscle cells 3. Lowers the pH of the blood, as more CO2 is dissolved in it, becomes more acidic. 4. Causes haemoglobin to change shape. 5. Haemoglobin releases and it unloads its oxygen is available to the cells fro respiration
17
Q

How is CO2 transported through the blood in different ways.

A

5% of CO2 transported in solution in the plasma. 10% is transported, as it combines with haemoglobin as carboaminohaemoglobin. 85% is transported as hydrogen carbonate ios (HCO-) in the blood.