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SHHS - Science - NEW AQA A-Level Biology (Year 1) > Mass Transport in animals > Flashcards

Flashcards in Mass Transport in animals Deck (31):

Give some ways in which cardiac output is increased during vigorous exercise

Increased heart rate
Increased stroke volume
More adrenaline


Explain what causes the blood pressure in the aorta to be higher than the blood pressure in the pulmonary artery

Left ventricle has thicker muscle


Explain why a vein is described as an organ

It's made of tissue


Explain how the elastic tissue helps even out the pressure of the blood going through the arteries

Elastic tissue stretches when pressure gets too high
And recoils when pressure returns to normal


The Cardiac cycle is controlled by the sinoatrial node (SAN) and the atrioventricular node (AVN). Describe how

The SAN initiates heartbeat
SAN sends waves of electricity across the atria causing atrial contraction
AVN delays to allow the atria to empty (and the ventricles to fill up) before the ventricles contract
AVN them sends a wave of electrical impulses down "bundle of His"
This causes the ventricles to contract from the base up (ventricular systole)


An increase in respiration in the tissues of a mammal affects the oxygen dissociation curve of haemoglobin. Describe and explain how

Increase in carbon dioxide so the curve moves to the right


People living in high altitudes have more red blood cells than people living at sea level l. Explain the advantage of this to people living at high altitudes

They will have more haemoglobin so can pick up more oxygen in the lungs


Explain how having a low protein diet can result in the accumulation of tissue fluid

The water potential in the capillaries is not as low as it is in a protein rich diet
So more tissue fluid is formed at the arteriole end and less water is absorbed into the capillaries (at the venular end) by osmosis


Explain ways in which the composition of tissue fluid differs from that of blood plasma

Tissue fluid contains little protein (as protein molecules are too large to pass through the capillary walls)
Tissue fluid contains less glucose as some of the glucose will have entered tissue cells


Explain how fluids leave the capillaries at the arterial end

Hydrostatic pressure is greater than the osmotic effect so molecules are forced out


Explain the meaning of the term atheroma

A fatty deposit forming in cells in the artery wall


Explain why atheroma may lead to a blood clot

The fatty substance narrows the arteries
This results in an uneven flow of blood and can damage the endothelium


Explain how the shape of a red blood cell allows it to take up a large amount of oxygen in a short time

It's has a large surface area to volume ratio for diffusion

It is flat and thin so oxygen can reach all haemoglobin rapidly


Describe how the increase in pressure of the blood in the arteries is a result from the events in the cardiac cycle

Increase in blood pressure caused by blood leaving the heart and entering the arteries
This is a result of ventricular systole


Describe the part played by proteins in the plasma in returning tissue fluid to the capillaries

A high concentration of protein produces a lower water potential so water moves into the capillaries by osmosis


Give some changes that will increase blood flow through the skeletal muscles

Increase in heart rate
Increased volume of blood pumped per beat
Dilation of vessels
Increased blood pressure


Explain some advantages of increasing the blood flow through the skeletal muscles during exercise

More oxygen supplied for respiration so less anaerobic respiration
More glucose supplies for respiration
Carbo dioxide rapidly removed from respiring cells


Describe how the regular contractions of the atria and the ventricles is initiated and coordinated by the heart itself

Cardiac muscle is myogenic
SAN sends a wave of electrical impulses across the atria
This initiates the contraction of the atria
AVN then spreads an electrical signal across the ventricles causing the ventricles to contract once they have filled with blood


During exercise the oxygen dissociation curve moves tot the right. Explain the advantage of this

Haemoglobin releases more oxygen for respiration


Describe how haemoglobin loads and unloads oxygen in the body

Haemoglobin picks up oxygen at high partial pressures e.g. In the lungs
Haemoglobin unloads oxygen at low partial pressures e.g. In respiring tissues


Explain how the structure of arterioles enables the regulation of blood flow to different parts of the body

Muscles in the walls for the arterioles contact increasing blood flow


When is the arterial pressure at its maximum value?

When the ventricles are contracting


If the oxygen dissociation curve is further to the left it means the haemoglobin has a _____________ affinity for oxygen



If the oxygen dissociation curve is further to the right it means the haemoglobin has a _____________ affinity for oxygen



the hydrostatic pressure falls from the arteriole end of the capillary to the venuole end - why?

loss of fluid/water


give 2 ways the structure of the fishes gills are adapted for gas exchange

many lamellae/filaments so a large SA
thin so a short diffusion pathway


How does the countercurrent flow in fish ensure max amount of oxygen passes into the blood flowing through the gills?

1. water and blood flow opposite directions
2. blood always meets water with a higher concentration of oxygen
3. diffusion gradient maintained across the full length of the gill


give 2 ways the aorta structure is suited to function

1. Elastic tissue - stretch and recoil /spring back
2. muscle layer for contraction
3. Thick walls to resist pressure and stop it bursting
4. smooth endothelium - reduces friction
5. semi lunar valve - prevents back flow


How is an insects tracheal system adapted for gas exchange?

1. tracheoles thin walls SO short diffusion distance
2. highly branched so short diffusion distance
3. highly branched so a large surface area
4. abdonimal pumping to move air SO maintains concentration gradient


Role of the heart in TF formation?

contraction produces a high pressure
This forces WATER (and dissolve substances) out of the capillaries


Blockage of lymphatic system could cause lymphodema - HOW?

prevents EXCESS TF from returning