3.3.4.1 Mass Transport in animals Flashcards
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
Greater
If the oxygen dissociation curve is further to the right it means the haemoglobin has a _____________ affinity for oxygen
Lower
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?
- water and blood flow opposite directions
- blood always meets water with a higher concentration of oxygen
- diffusion gradient maintained across the full length of the gill
give 2 ways the aorta structure is suited to function
- Elastic tissue - stretch and recoil /spring back
- muscle layer for contraction
- Thick walls to resist pressure and stop it bursting
- smooth endothelium - reduces friction
- semi lunar valve - prevents back flow
How is an insects tracheal system adapted for gas exchange?
- tracheoles thin walls SO short diffusion distance
- highly branched so short diffusion distance
- highly branched so a large surface area
- 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
name the blood vessels that carry blood to the heart muscle
coronary arteries
binding of one molecule of oxygen to Hb makes it easier for a second oxygen to bind - why?
- binding of the 1st changes to tertiary structure
2, uncovering 2nd binding site
explain the difference in thickness between the pulmonary artery and the pulmonary vein?
- high pressure smooths out blood flow
- artery wall contains more collagen
the thickness in the aorta wall changes all the time during each cardiac cycle. explain why?
- aorta wall stretches because ventricle pressure increases
- aorta wall recoils because ventricles relax
- maintains smooth flow
which blood vessel shows greatest variation in wall thickness?
aorta
describe how tissue fluid is formed AND how it is returned to the circulatory system?
FORMATION
- high hydrostatic pressure
- forces fluid out
- large proteins remain in capillary
RETURN
- lower water potential in capillary
- due to plasma proteins
- water enters capillary by osmosis
explain how oxygen is loaded, transported and unloaded in the blood?
- haemoglobin carries oxygen
- association happens in lungs
- at high partial pressure of oxygen
- unloads to respiring cells and tissues
- at low partial pressures of oxygen
- unloading linked to higher co2 concentration
african lungfish are likely to survive for longer than australian lungfish when living in pools that dry up. why?
- most exchange is via lungs
- gills function less efficiently in air
high blood pressure leads to an accumulation of tissue fluid. explain how?
- high blood pressure = high hydrostatic pressure
- increases outward pressure from arterial end of capillary
- so more tissue fluid formed
describe and explain the mechanism that causes forced expiration?
- internal intercostal muscles contract
- external intercostal muscles and diaphragm relax
- ribcage moves down and in
- diaphragm domes up
- thorax volume decreases
- air pushed down pressure gradient
water potential of blood plasma is more negative at the venule end of the capillary than at the arteriole end of the capillary. explain why?
- water moves out of capillary
- large proteins remain because too large to exit capillary
- therefore lowering wp due to higher concentration of proteins
explain how asthma attack causes drop in mean FEV?
- muscle walls of bronchi contract
- walls of bronchi secrete more mucus
- diameter of airway reduced
- flow of air reduced
describe how oxygen in the air reaches capillaries surrounding alveoli in the lungs.
details of breathing not required
- bronchi, bronchioles, trachea, alveoli
- down pressure gradient
- down diffusion gradient
- across alveolar epithelium
the oxygen disassociation curve for haemoglobin shifts to the right during vigorous exercise. explain advantage of this shift?
- haemoglobin has lower affinity for oxygen
- oxygen unloaded MORE READILY
- to respiring cells
- for rapid respiration
describe and explain changes in rate of blood flow to different organs during a long dive?
- brain stays the same whilst all others fall
- during exercise blood rushes to brain as it needs constant supply
describe and explain how the lungs are adapted to allow rapid exchange of oxgen between air in the alveoli and blood in the capillaries around them?
- many alveoli - large surface area
- many capillaries - large surface
- so FAST diffusion
- alveoli wall lining thin - short dist between alveoli and blood
- flattened epithelium
- so SHORT diffusion pathway
- so FAST diffusion
- ventilation
- maintains diffusion gradient
- so FAST diffusion
bloods journey
- blood enters the heart in the vena cava (deoxygenated)
- moves through the right atrium, right ventricle
- blood pumped out of heart to the lungs via the pulmonary artery,
- exchange of oxygen and carbon dioxide occurs at the alveoli
- blood returns to the heart in the pulmonary vein (oxygenated) to the left side
- into the left atrium, left ventricle.
- then blood is forced out of the heart to the body in the aorta – delivering oxygen to respiring tissues.
define atheroma
build up of fatty plaque in arteries
define thrombosis
blood clot in arteries
define aneurysm
when stretchy endothelium balloons out through muscle of artery
atheroma problems
- can cause thrombosis and aneurysm
- can block arteries
- if blocks coronary arteries
- can cause myocardial infarction
- reduces flow of of oxygen and glucose to heart muscle
- CANT respire
abdominal pumping increases the efficiency of gas exchange between tracheoles and muscles tissue of insect
why?
- more oxygen enters quicker
- maintains GREATER diffusion gradient
abdominal pumping is an adaptation not found in many small insects
these small insects obtain sufficient oxygen by diffusion
explain how their small size enables gas exchange to be efficient without the need for abdominal pumping?
shorter diffusion distance
the ends of tracheoles connect directly with the insects muscle tissue and are filled with water
when flying, water is absorbed into the muscle tissue
removal of water from the tracheoles increases the rate of diffusion of oxygen between the tracheoles and muscle tissue
suggest why
greater surface area exposed to air
scientists investigated the benefits of breast milk compared with formula milk.
the scientists used kittens as model organisms
other than ethical reasons, suggest 2 reasons why they chose to use cats as model organisms
- are mammals - likely have same reactions as humans
- produce enough milk to extract
- use large amount
before starting their experiments, the scientists confirmed that, like human breast milk, cats milk also contained bile-activated lipase.
to do this, they added bile to cats milk and monitored the pH of the mixture
explain why monitoring the pH of the mixture could show whether the cats milk contained lipase
- hydrolysis of lipids produces fatty acids
- which lowers pH of mixture
