TRANSPORT IN MAMMALS Flashcards
Describe the structure of an artery
Carry blood at high pressure away from the heart.
Narrow lumen relative to cell diameter
Thick walls:
Inner layer-Endothelium
Middle layer- Elastic fibre and smooth muscle
Outer layer-collagen and a little elastic fibre
Describe the structure of a vein
Carry blood at low pressure to the heart
Wide lumen relative to cell diameter
Thin walls
Contain semi-lunar valves
Structure of capillary related to its function
1) Thin wall made of a single layer of endothelium-shorter diffusion distances
2) They are numerous and highly branched therefore provide a large surface area for diffusion to take place on
3) Narrow lumen 7up - RBC can squeeze flat against them bringing them closer to the respiring cells enabling efficient transport of oxygen as diffusion distances are reduced
4) Have endothelial pores- Allow small substances such as glucose, amino acids, neutrophils to leak out of blood into the fluid surrounding the body- speeds up delivery and collection of substances
Structure of capillary related to its function
1) Thin wall made of a single layer of endothelium-shorter diffusion distances
2) They are numerous and highly branched therefore provide a large surface area for diffusion to take place on
3) Narrow lumen 7up - RBC can squeeze flat against them bringing them closer to the respiring cells enabling efficient transport of oxygen as diffusion distances are reduced
4) Have endothelial pores- Allow small substances such as glucose, amino acids, neutrophils to leak out of blood into the fluid surrounding the body- speeds up delivery and collection of substances
What are the dissolved substances found in plasma?
Nutrients - glucose and amino acids
Waste products - Urea
Ion- calcium and iron
Hormones- insulin and adrenaline
Plasma proteins-Fibrinogen, prothrombin, albumin
Respiratory gases- oxygen and carbon dioxide
Immuno-globins
What are the roles of water in blood plasma?
Solvent
high specific heat capacity
Describe the structure of Red blood cells related to its function
Biconcave shape- provides a large surface area to volume ratio of the cell which means that oxygen can diffuse quickly into and out of the cell
Very small -7up - No Hb molecules are far from the cell surface membrane of the red blood cell therefore can easily exchange oxygen from fluid outside
-It can squeeze through capillaries bringing it closer to cells
Flexible- able to squeeze through the capillaries and change shape and then spring back to their biconcave shape
Contain heamoglobin- carries oxygen from lungs to respiring tissues
Does not contain nucleus, endoplasmic reticulum, mitochondria- increases the space available for heamoglobin maximising the amount of oxygen which can be carried
Function of the coronary arteries
supply the heart with oxygen and nutrients
Septum
layer of tissue separating the left side of the heart from the right side
Aorta
Connected to the left ventricle and it transports oxygenated blood around the body
Vena Cava
It is connected to the right atrium
It brings deoxygenated blood from body to the heart
Pulmonary artery
Connected to the right ventricle
Carries deoxygenated blood from the heart to the lungs
Pulmonary Veins
Connected to the left atrium
Brings to the heart oxygenated blood from the lungs
Why are the walls of the ventricles thicker than the walls of the atria?
The atria is thin walled and elastic. It has very little resistance to blood flow as it passes blood to a short distance of the ventricle. Hence less cardiac muscle is required
Ventricles have thicker walls because they transport blood longer distances-either to the lungs or body- therefore they present a resistance to the blood flowing through them..to overcome this resistance more cardiac muscle is required.
Why are the walls of the left ventricle thicker than the right ventricle?
The right ventricle pumps blood to the lungs which is a short distance away. There is very little resistance to blood flow in pulmonary circulation therefore less cardiac muscle is required thus they have thinner walls.
The left ventricle pumps blood all around the body. It requires a thick muscular wall to enable it to contract and generate a high pressure to overcome the resistance in systemic circulation
