Topic 3 - Mass Transport in Animals Flashcards
What is the main fucntion of the mammalian blood system?
To transport nutrients like oxygen and ions and take waste away.
What are the four main components of the blood?
Plasma
Red Blood Cells
White Blood Cells
Platelets.
What is the function of red blood cells?
To transport oxygen
What is the function of white blood cells?
Immune response, protect from pathogen
What is the function of platelets?
Blood clotting
What is haemoglobin?
A red pigment that transports oxygen around the body.
What is the structure of haemoglobin?
Globular, soluble protein with quarternary structure.
How many haem groups does one haemoglobin molecule contain?
Four haem goups in one haemoglobin
How many oxygen molecules can bind to each haemoglobin molecule?
Each haem group can combine temporarily with with one oxygen molecule, so one haemoglobin can bind to four O2 molecules or 8 oxygen atoms.
How is oxyhaemoglobin formed?
From oxygen and haemoglobin combining.
What is the partial pressure of oxygen?
The partial pressure of oxygen is a measure of oxygen concentration.
What causes the pO2 to increase?
When oxygen loads onto haemoglobin
What causes the pO2 to decrease?
When oxyhaemoglobin unloads its oxygen.
What happens to pO2 during respiration?
When cells respire, they use up oxygen, lowering the pO2.
What does the oxyhaemoglobin dissociation curve show?
A dissociation shows how saturated the haemoglobin is with oxygen at any given partial pressure.
What does it mean if the oxygen dissociation curve for haemoglobin shifts right.
There is more CO2, giving up more oxygen for respiring cells.
What is CO2 converted to in red blood cells?
Hydrogen carbonate Ions (HCO3)
How does pressure impact the dissociation?
Haemoglobin gives up its oxygen more readily at high partial pressures of CO2 and the curve shifts to the right.
Why is the dissociation curve s-shaped?
The s-shaped curve for haemoglobin results from the cooperative binding of oxygen; once one oxygen has bound to a haem group, it becomes easier for the next three oxygen molecules to bind to the other three haem groups.
Where in the body is pO2 low?
In the respiring tissues
Where in the body is pO2 high?
In the lungs
What type of system is the circulatory system?
A double circulatory system: pulmonary system and systemic system
What are the two chambers in the heart?
Atrium and ventricle
What are the characteristics of the atrium?
Thin walled and elastic, the atrium can stretch when filled with blood.
What are the characteristics of the ventricle?
Thick muscular wall to pump blood around the body or to the lungs.
What is between the atria and ventricles?
The left and right atrioventricular valves
What are the four main vessels in the heart?
Aorta, Pulmonary artery, Pulmonary vein and vena cava
What is the structure and function of the aorta?
Connected to the left ventricle and carries oxygenated blood to all the body except the lungs.
What is the strcucture and function of the pulmonary artery?
Connected to the right ventricle and carries deoxygenated blood to the lungs where it is oxygenated and the CO2 is removed.
What is the structure and function of the pulmonary vein?
Connected to the left atrium and brings oxygenated blood back from the lungs.
What is the structure and function of the vena cava?
Connected to the right atrium and brings deoxygenated blood back from the tissues except the lungs.
Why is the heart reffered to as myogenic?
The heart is referred to as myogenic as it is able to initiate its own contractions.
What is the sinoatrial (SA) node?
SA node in the wall of the right atrium is the pacemaker of the heart.
What is the function of the SA node?
The SA node initiates a wave of electrical stimulation which causes the atria to contract at roughly the same time.
What is the function of the AV node?
It passes on the excitation to the ventricles, down the bundle of His to the apex of the heart.
What is the function of the bundle of His?
The bundle of His branches into Purkinje Fibres which carry the wave upwards. This causes the ventricles to contract, thus emptying them.
What are three stages of the cardiac cycle?
Cardiac diastole, Atrial systole and ventricular systole.
What happens in cardiac diastole?
1) Blood enters the atria.
2) AV valve opens.
3) Blood passes into the ventricle as there is a high pressure in the atria and low pressure in the ventricle.
4) AV valve closes as pressure is now higher in the ventricle than in the atria to avoid backflow.
5) SLV closes as there is higher pressure of blood in the arteries than in the ventricle.
What happens in atrial systole?
1) Atria pressure increases.
2) AV valve is open meaning blood goes into the ventricle.
3) SLV stays closed.
What happens in ventricular systole?
1) Ventricle pressure increases.
2) Pressure in the ventricle is higher than in the atria so the AV valve closes to avoid backflow.
3) Pressure in the ventricle becomes higher than in the arteries so SLV opens.
4) Blood leaves ventricles at high pressure.
What is the function of arteries?
Adapted to carrying blood away from the heart to the rest of the body.
How are the arteries adapted to their function?
Thick walled to withstand high blood pressure. Contain elastic tissue which allows them to stretch and recoil, smoothing blood flow. Smooth muscle allows a varied blood flow. Smooth endothelium reduces friction and eases the flow of blood.
What is the function of arterioles?
Branch off arteries
How are the arterioles adapted to their function?
Thinner and less muscular walls. Feed blood into the capillaries.
What is the function of capillaries?
Smallest blood vessels
How are capillaries adapted to their function?
Site of metabolic exchange.
One cell thick for fast exchange of substances.
What are venules?
Larger than capillaries but smaller than veins.
What is the function of veins?
Carry blood from the body to the heart.
How are the veins adapted to their function?
Wide lumen to maximise volume of blood. Thin walled as blood flows at low pressure. Contain valves to prevent backflow.
What is tissue fluid?
Fluid containing water, glucose, amino acids, fatty acids, ions and oxygen which bathes the tissue.
What is oncotic pressure?
When there is movement of fluid out of the capillaries, due to hydrostatic, the water potential of the capillaries becomes more negative.
How is tissue fluid formed?
1) Capillaries have small gaps in the walls so that liquid and small molecules can be forced out.
2) As blood enters the capillaries from arterioles, the smaller diameter results in a high hydrostatic pressure so water, glucose, amino acids, ions and oxyge are forced out in ultrafiltration.
3) Large molecules remain in the capillaries and therefore create a lowered water potential.
4) Towards the venule end of the capillaries, the hydrostatic pressure is lowered due to the loss of liquid, but the water potential is very low.
