Animal Transport Flashcards
What is an open circulatory system?
Blood not held within blood vessels
What organisms use an open circulatory system?
Insects
How does the heart pump blood towards the head in an open circulatory system?
Peristalsis
What is a closed circulatory system?
Where blood is enclosed in the blood vessels
What are the benefits of a closed circulatory system?
Blood pumped at higher pressure, blood flow more rapid and efficient, more efficient delivery of O2 and nutrients and removal of waste products
What is the order of a single circulatory system, and where can you find it?
Found in fish
Heart - gills - body - heart
What is the order of a single circulatory system?
Pulmonary: heart - lungs - heart
Systemic: heart - body - heart
What are the advantages of a double circulatory system?
Increased pressure in systemic system, decreased pressure in pulmonary system, more efficient O2 and nutrient delivery
Which blood vessel pumps oxygenated blood away from the heart to the body?
Aorta
Which blood vessel pumps deoxygenated blood away from the heart to the lungs?
Pulmonary artery
Which blood vessel pumps deoxygenated blood towards the heart from the body?
Superior vena cava from brain
Inferior vena cava from below heart
Which blood vessel pumps oxygenated blood towards the heart from the lungs?
Pulmonary vein
What is the muscle in the middle of the heart called?
Septum
Where are the atrioventricular valves found? (tricuspid and bicuspid)
Between the atrium and ventricle on both sides of the heart
Where are the semi-lunar valves found?
Between the ventricles and either the aorta or pulmonary artery
How many stages are there in the cardiac cycle?
3
What happens in the first stage of the cardiac cycle?
Blood enters the atria via vena cava and pulmonary vein. Atria contracts, volume decreases, pressure increases
Atrioventricular valves are open Semi-lunar valves are closed
What happens in the second stage of the cardiac cycle?
Blood enters the ventricles down the concentration gradient through the atrioventricular valves
Atrioventricular valves are open Semi-lunar valves are closed
What happens in the third stage of the cardiac cycle?
Ventricles contract, volume decreases and pressure increase. Blood is forced through the semi-lunar valves into the aorta and pulmonary artery
Atrioventricular valves are closed
Semi-lunar valves are open
When do atrioventricular valves open?
When pressure in atria is greater than pressure in ventricles. Flow down a pressure gradient
When do atrioventricular valves close?
When pressure in ventricles is greater than pressure in atria. They close to prevent backflow of blood from ventricle to atrium
When do semi-lunar valves open?
When pressure in ventricles is greater than pressure in atria. Flow down a pressure gradient
When do semi-lunar valves close?
When pressure in atria is greater than pressure in ventricles. They close to prevent backflow of blood from aorta/pulmonary artery to ventricles
What does myogenic mean?
Happens automatically
What is diastole?
When the heart relaxes
What is systole?
When the heart contracts
What are the stages of electrical control?
SAN initiates wave of excitation
Causes atrial systole
Prevented from causing ventricular systole due to a thin no-conductive tissue layer
AVN delays the electrical impulse allowing atrial systole to finish before ventricles contract
Electrical impulse travels down bundle of His in the septum
Reaches the bottom of the ventricles and causes contraction
Travels up the purkinje fibres causing ventricular systole
Diastole occurs as electrical impulse is terminated
What does ECG stand for?
Electrocardiogram
What does bradycardia mean?
Fast
What does tachycardia mean?
Slow
What happens at the P wave of an ECG?
Depolarisation of the atria
Atrial systole
What happens as the QRS complex of an ECG?
Depolarisation of ventricles
Ventricular systole
What happens at the T wave of an ECG?
Repolarisation of ventricles
Ventricular diastole
What are the properties of arteries?
Thickest muscle wall and cell wall, most elastic, no valves, has an endothelium, small lumen
What are the properties of veins?
Thin muscle wall and thin cell wall, least elastic, has valves, has an endothelium, large lumen
What are the properties of capillaries?
No muscle, no elasticity, 1 cell thick, no valves, has an endothelium, smallest lumen
What is an endothelium used for in blood vessels?
Reducing friction
What are the layers of arteries and capillaries called from the outer layer inwards?
Tunica externa (elastin and collagen)
Tunica media (smooth muscle)
Tunica interna (endothelial cells)
What is the relationship between total cross-sectional area and velocity of flow?
As total cross-sectional area increase, velocity decreases as more friction and pressure spreads out
What happens at the arteriole end of the capillary bed in the formation of tissue fluid?
Hydrostatic pressure is high due to contraction of left ventricle.
Water potential of blood is lower than in the tissue fluid meaning water wants to move into blood via osmosis. However the high hydrostatic pressure causes net movement of fluids out of the blood and into the tissue fluid, making it be high in oxygen glucose and amino acids. Oxygen and glucose will be used by cells in respiration which ensures a concentration gradient is maintained. CO2 and waste products diffuse into tissue fluid.
What happens at the venous end of the capillary bed in the formation of tissue fluid?
Hydrostatic pressure is lost due to loss of fluid from the capillary. Due to RBC’s, WBC’s and plasma proteins, water potential in blood is lower than tissue fluid. Net movement of fluid into capillary by osmosis. Fluid contains a lot of waste products which will eventually be returned to the lungs and exhaled.
What is tissue fluid?
Fluid by which substances are exchanged between blood and cells. It supplies tissues with essential solutes in exchange for waste products to be exhaled
What happens to the levels of saturation within haemoglobin at a high partial pressure of oxygen (pp02) e.g. the lungs?
Haemoglobin has a high affinity for oxygen. Associates with oxygen very easily. Oxyhaemoglobin (Hb4O2) doesn’t release O2 easily.
What happens to the levels of saturation within haemoglobin at a low partial pressure of oxygen (pp02) e.g. the respiring tissue?
Haemoglobin has a low affinity for oxygen. Disassociates from oxygen very easily. Oxyhaemoglobin (Hb4O2) doesn’t easily load O2
What is the structure of haemoglobin?
Quaternary structure, contains 4 polypeptides, globular in shape
What does the sigmoid curve imply about the readiness of haemoglobin to associate with oxygen?
At low ppO2 the haemoglobin does not easily take up oxygen.
Once the first oxygen has associated, Hb changes shape making it easier for the next two oxygens to associate. At a high ppO2, is difficult for the last oxygen to attach as hard to reach 100% saturation.
What is the general rule of a dissociation curve that is displaced to the right?
The more the curve is displaced to the right , the more readily haemoglobin will dissociate from oxygen and less readily it will associate with oxygen
Why does the curve shift to the right?
CO2 diffuses into the RBC
The CO2 reacts with water in the presence of carbonic anhydrase
Carbonic acid forms
Splits into hydrogen ions and hydrogen carbonate ions
Hydrogen carbonate ions exit the RBC into the plasma
Chloride ions enter the RBC
Hydrogen ions bind to haemoglobin to form haemoglobinic acid and dissociate from the oxygen which is supplied to the respiring tissues
The oxygen dissociation curve will shift to the right. Called the Bohr shift
What is the general rule of a dissociation curve that is displaced to the left?
The more the curve is displaced to the right , the more readily haemoglobin will associate with oxygen and less readily it will dissociate from oxygen
How is myoglobin different to haemoglobin?
Myoglobin is found in muscle cells
Haemoglobin is found in RBC’s
Myoglobin only has one haem group and combines with one oxygen
Haemoglobin has four haem groups and combines with four oxygens at very high ppO2
Is the haemoglobin curve for a foetus to the left or the right of a maternal one?
Because pp02 is lower in placenta, so haemoglobin diffuses in. The foetal haemoglobin has a higher affinity for oxygen so associates and foetus uses the o2 for respiration. Therefore the curve is to the left
What is cooperative binding?
When oxygen binds to haemoglobin. 1st o2 molecule binds easily and changes shape of haemoglobin. Second molecule attaches and changes shape. Third molecule attaches but doesn’t change shape. Fourth molecule only attaches if large increase in ppo2
How does CO2 effect the oxygen dissociation curve?
The higher the CO2 levels, the further to the right the curve is. Due to oxygen competing with H+ ions for space on haemoglobin
What is the molecule with the chemical formula H2CO3?
Carbonic acid
What is the molecule with the chemical formula HcO3?
Hydrogen carbonate ions
What is the molecule with the chemical formula HHb?
Haemoglobinic acid
How does increasing carbon dioxide levels in the plasma cause haemoglobin to release the oxygen it is carrying?
- CO2 diffuses into RBC cytoplasm
- CO2 reacts with H2O to form carbonic acid which is catalysed by carbonic anhydrase. CO2 +H2O ⇌ H2CO3
- Carbonic acid is unstable and splits into H+ and HcO3-(hydrogen carbonate) ions. H2CO3 –> H+ + HCO3-
- Hydrogen carbonate ions diffuse out of RBC and chloride shift occurs to maintain correct charge
- H+ ions cause oxyhaemoglobin to dissociate and H+ binds to Hb to form HHB (haemoglobinic acid) and oxygen is ‘pushed off’ into tissue fluid and diffuses into cells
