Mass transport in animals

• structure and role of arteries

  • thick layer of collagen to act as connective tissue
  • thick layer of smooth muscle which allows the change in diameter of the lumen to control the blood flow
  • elastin layer which tissue expands and then recoils to maintain high hydrostatic pressure
  • endothelium which is one cell thick
• adaptations of red blood cell

  • flexible so able to be transported around the vessels
  • the cells are tiny and very thing which allow a short diffusion pathway
  • no nucleus to allow space for hemoglobin
  • biconcave shape to allow a greater surface area for exchange
• adaptations and role of capillaries

  • trillions in number which give large surface area
  • narrow lumen which slows the flow of substances and so allows exchange to occur
  • endothelium is one cell thick which provides a short diffusion pathway
  • fenestration is evident to allow larger molecules through
• adaptations and role of veins

  • thin layer of collagen
  • smooth muscle layer
  • elastin layer
  • endothelium
  • valves to prevent backflow as flood is carried at low pressure
  • wide lumen to allow more blood to pass through
• heart rate = number of times per minute that ventricles contract
• stroke volume = amount of blood pumped out by the left ventricle with every contraction
• cardiac output = stroke volume x heart rate
• what are the components of the blood?

  plasma, erythrocytes, white blood cells and platelets
• why is tissue fluid needed to be reabsorbed

  otherwise swellings can occur in the body due to lack of liquid in the blood
• what is not forced out with the tissue fluid?

  plasma proteins as they are too large which decreases the water potential and so water cam be reabsorbed by the venule end via osmosis
• describe the formation of tissue fluid

  high hydrostatic pressure forces the tissue fluid of of the capillary walls near the arteriole end which is known as ultrafiltration. the high pressure is caused by the small diameter of the lumen
• function of tissue fluid

  • delivers oxygen and nutrients to the cell
  • collects waste products from cells
  • facilitates gaseous exchange
• role of lymphatic system

  some liquid may not get reabsorbed due to the reaching of equilibrium of water potential. therefore rest goes into the lymphatic system. the system uses it lymph vessels and capillaries to eventually drain back the tissue fluid back into the bloodstream near the heart
• structure of hemoglobin

  • quaternary globular structure
  • 4 different chains of polypeptides
  • each haem group can bind to one oxygen molecule
  • can bind with 4 oxygens to form oxyhaemoglobin
• what effect does increased pp02 have

  • haemoglobin will have a higher affinity for oxygen and so a higher saturation of oxgyen
• what effect does a lower pp02 have

  haemoglobin will have a lower affinity for oxygen and so its dissociation increases, releasing the oxygen, resulting in a lower saturation
• why is there a steep part in the dissociation curve

  to represent how a small change in pp02 has a very large change of saturation and how it is hard to gain the first oxygen molecule but after cooperative binding is much easier
• describe the s shaped dissociation graph

  • when hb combines with its first 02 molecule its shape alters to allow the easier binding of the other molecules
  • but as the hb starts to become saturation it gets harder for more oxygen molecules to join
• explain the bohr shift

  when the line shifts to the right, hb behaves in a way where it has a lower affinity for oxygen and so will dissociate more
• describe the relationship between a fetal and it mothers affinity for oxygen

  at the same pp02, the mothers saturation will be lower as there is a higher dissociation of the oxygen in the haemoglobin. the fetus has a much higher affinity for oxygen and so a higher saturation
• explain the effect of sport on the affinity for oxygen

  in sport, exercise leads to a high amount of respiration in the muscles ad so large amounts of c02 is being released which produces carbonic acid which alters ph in the blood. As a result the affinity of haemoglobin for oxygen decreased so more oxygen is given out and dissociates by the haemoglobin to the tissues to use for further respiration.
• explain the effect of increasing altitude of affinity for oxygen

  at high altitudes, there is a decrease pp02 and decrease amount, as a result it is beneficial to have a haemoglobin with a higher affinity for oxygen in order to take and bind cooperatively as much as possible
• what is sclerosis

  the hardening of the wall
• what is stenosis

  narrowing of the lumen
• what is a heart attack otherwise known as

  myocardial infarction
• what is angina

  where the heart muscle cells havent got enough oxygen and so respire anaerobically
• what stems the coronary heart issues

  muscle of the heart is deprived of oxygen and so cannot respire so will die
• what is an aneurism

  blood vessel wall is weakened and when blood passes through the area is grows and will pop
• what is an atheroma

  if the endothelium is damaged by high blood pressure there is an inflammatory response where white blood cells and platelets go behind the cell. this can build and block the lumen of the artery and restrict the blood flow
• what is atherosclerosis

  blood vessel becomes stiffer and prevents elastic from recoiling
• what is it called when a muscle is contracting?

  systole
• what is it called when a muscle is relaxing

  diastole
• when do the chambers of the heart contract?

  both atriums contract and the same time and so do the two ventricles.
• role of tendorous cords

  anchor the valves and prevents inversion of valves
• describe the muscle of the heart

  cardiac muscle and is myogenic so makes itself contract to force movement of the blood
• when do the av valves close?

  when the ventricular pressure is greater than the atrial
• when doe the semiluna valves open

  when the ventricular pressure is greater than the aortic
• when do the semi luna valves close

  when the aortic pressure is greater than the ventricular
• when do the av valves open

  when the atrium pressure is greater than the ventricular pressure
• describe the difference in ventricular volume

  when ventricle contracts and is in systole the volume decreases and pressure increases

  when ventricle relaxes and blood flows in as the valves open the volume increases