cardiovascular system Flashcards
(16 cards)
what is plasma and what does it contain?
plasma is the liquid part of blood
it contains: salts, urea, glucose, amino acids vitamins, etc
what is the function of leukocytes?
leukocytes are white blood cells that are part of the immune system, they help fight infections
what is the function of platelets?
involved in blood clotting, prevent excessive blood loss
what are erythrocytes?
red blood cells deliver oxygen and carbon dioxide throughout the body
what are the adaptations of red blood cells
binconcave shape: increase surface area for faster diffusion of oxygen
no nucleus or mitochondria: provides more room for haemoglobin
what does partial pressure mean?
pressure exerted by one gas in a mixture of gases
how is carbon dioxide transported?
10% of carbon dioxide diffuses into the red blood cells and combine with haemoglobin to form carbaminohaemoglobin
most CO2 reacts with water to form carbonic acid (catalysed by carbonic anhydrase)
carbonic acid dissociates into hydrogen ions and hydrogen carbonate ions (HCO3)
why does haemoglobin react with hydrogen?
haemoglobin acts as a buffer therefore combines with hydrogen ions to remove them from the blood so hydrogen ions don’t interfere with the pH of the blood.
what does the Bohr effect state?
In tissues, where the partial pressure of carbon dioxide is high, haemoglobin will release oxygen more readily to combine with carbon dioxide. This is essential for actively respiring tissues that require more oxygen.
what is the oxygen dissociation curve?
S shaped curve explains how haemoglobin releases and binds to oxygen.
The first binding with oxygen is hard therefore haemoglobin needs to go through conformational changes to make it easier for the next oxygen molecules to bind
what is fetal haemoglobin?
fetal haemoglobin has higher affinity for oxygen than adult haemoglobin. This allows the fetus to absorb oxygen from the mothers blood ensuring proper growth and development
what are the events of blood clotting?
- Damage to endothelium causes platelets to break open and release certain chemicals that trigger a cascade of reactions to form a clot.
2.Thromboplastin: catalyses the conversion of inactive prothrombin to active thrombin.
Serotonin: causes muscle contractions to narrow blood - Thrombin catalyses the conversion of fibrinogen into fibrin
- Fibrin creates a mesh that traps platelets are red blood cells to create a clot
what is the role and structure of arteries?
Arteries carry blood away from the heart
Structure: Inner layer (tunica intima): made out of endothelium which is a smooth lining that reduces friction and resistance, allows smooth blood flow
Tunica media (middle layer) consist of elastic fibres that allow stretching and recoiling of the arterial wall to help maintain constant blood pressure
smooth muscle: regulate the diameter of the artery, controlling blood pressure
Outermost layer: tough tissue to prevent rupture and withstand high pressure
Narrow lumen that increases blood pressure
what are the structure and function of veins?
Veins carry blood towards the heart
Structure: thin walls (blood is at lower pressure)
large lumen: allow a greater volume of blood flow
valves! prevent the back flow of blood and ensure a one way direction
what are the structure and function of capillaries?
Capillaries are responsible for the exchange of substances between blood and tissues
Structure: one layer of endothelial cells: allow rapid diffusion
Small diameter: maximises the time for diffusion to occur
