Blood and Haemoglobin Revision Carousel Flashcards
Why can proteins known as plasma proteins not leave the blood?
They are too large to pass between the squamous cells of the capillary wall
Describe how capillaries are adapted for exchange.
-Narrow lumen;squeezes red blood cells against walls so transfer of oxygen is better to the tissues
-Walls consist of a single layer of endothelial cells:reduces diffusion distance
-Permeable walls:allow blood plasma and dissolved substance to leave the blood
Describe how veins are adapted to carry blood back to the heart.
-Wide lumen to ease blood flow
-Thin layers of elastic/muscle/collagen in walls as no need to stretch and recoil
-valves to prevent back flow of blood
What is the role of arterioles?
-Take blood from artery to capillary
-Have a layer of smooth muscle which contract restricting and slowing blood flow
With reference to protein structure, explain how increasing hydrogen ion levels affects haemoglobin.
-More hydrogen ions = lower pH (more acidic cytoplasm)
-Tertiary structure to Hb is altered which reduces its affinity for oxygen
What is the process known as by which oxyhaemoglobin releases its oxygen to respiring cells?
Dissociation
What substance might affect the oncotic pressure of blood?
Dissolved solutes such as mineral ions, sugars and proteins
Describe the role of lymph fluid.
A system of tubes that returns excess tissues fluid to the blood system
Describe the simple structure of haemoglobin.
-4 subunits each with a polypeptide chain and haem group
-Haem groups each contain an Fe2+ iron at the centre which can attract and hold an oxygen molecule
What is oncotic pressure?
The pressure created by the osmotic effects of the solutes
What is the inner tissue lining of a blood vessel called? What is its role?
Endothelium which reduces friction with the flowing blood
What is the main difference between foetal haemoglobin and adult haemoglobin?
It has a higher affinity for oxygen than adult haemoglobin
What is the net result of the Bohr effect?
More oxygen is released where more carbon dioxide is produced in respiration
Describe the function of a venule.
Takes blood from capillaries to veins
State the cell types that are most likely to be found in blood plasma, tissue fluid and lymph.
Blood Plasma-RBC’s, neutrophils and lymphocytes
Tissue Fluid-neutrophils (especially during infection)
Lymph-lymphocytes
