blood Flashcards
blood is about what percentage of body weight
8%
what is the average volume of blood in women
5 litres
what is the average volume of blood in men
5.5 litres
what are the 3 types of specialized cellular elements suspended in plasma
Erythrocytes (red blood cells)
Leukocytes (white blood cells)
platelets
what is in plasma
water (90%)
electrolytes
nutrients, wasts, gases, hormones
plasma proteins
what is the function of electrolytes in plasma
Membrane excitability
osmotic distribution of fluid between ECF and ICF
buffer pH changes
what proteins are found in plasma
Albumins - most abundant
Globulins
Fibrinogen
what is the function of albumins
Contribute to the colloid osmotic pressure by virtue of their abundance
Transport molecules that are poorly soluble in plasma (eg) bilirubin
what are the subclasses of globulins
α, β and γ
what is the function of the α/β globulins in plasma
- α/β - Transport molecules (high specificity); blood clotting factors
what is the function of the α globulins in plasma
They inhibit certain blood proteases and show significant inhibitor activity
e.g. Angiotensinogen: Converted to angiotensin
what is the function of the γ globulins in plasma
- Immunoglobulins (antibodies) - Immunity
what is the function of Fibrinogen in plasma
clotting factor; converted to fibrin
what are the plasma proteins produced by
All produced by the liver - except for γ-globulins which are produced by lymphocytes
what is serum
plasma from which fibrinogen and other clotting proteins have been removed. When you centrifuge coagulated (clotted) blood the liquid portion is serum
how many Erythrocytes (red blood cells) are in the body
5 million per cubic millilitre
how long is the lifecycle of an Erythrocyte (red blood cells)
120 days
what is the production of blood cells called
Haemopoiesis
what is anemia
Refers to a below-normal O2-carrying capacity of the blood
what causes anemia
Reduced Haemoglobin content of RBCs (iron deficiency)
reduced RBC number ( reduced cell production)
name three types of anaemia
Nutritional anemia - Iron deficiency (can’t make sufficient haemoglobin)
Hemorrhagic anemia - Caused by losing a lot of blood
Aplastic anemia Failure of the bone marrow to produce enough RBCs
what is Thrombopoietin Hormone
produced by liver and increases number of
megakaryocytes and therefore increases platelet production
how do platelets work
Release serotonin to vasoconstrict & reduce blood flow to clot area
what is haemostasis
Process of keeping blood within a damaged blood vessel
what are the three steps of haemostasis
- vascoconstriction
- formation of a platelet plug
- blood coagulation (clotting)
describe the formation of the platelet plug
Platelets adhere to the exposed collagen in the damaged vessel wall
Platelets release ADP and serotonin which causes surface of nearby circulating platelets to become sticky and to adhere to first layer of aggregated platelets
describe blood clotting
A cascade of clotting factors (coagulation cascade) activates thrombin, an enzyme that converts fibrinogen into fibrin.
Fibrin fibers form a mesh around the platelet plug, stabilizing and reinforcing it into a strong blood clot (thrombus).
This clot prevents further blood loss and remains until tissue repair is complete.
what are the two pathways of blood clotting
Extrinsic: Shorter & faster
Intrinsic: Requires more upstream
factors
why is clotting potentially dangerous
Clot dissolution and Clot prevention
describe clot dissulution
plasmin is produced by plasminogen and dissolves clots
what is the function of thrombomodulin
Binds thrombin (So no fibrinogen
conversion)
Activates Protein C — anticoagulant
(inactivates active factors V and VIII).
what is Erthropoietin
glycoprotein hormone primarily produced by the kidneys in response to low oxygen levels in the blood (hypoxia). It stimulates the bone marrow to produce red blood cells
what are Gamma-globulins
globular proteins found in blood plasma, primarily composed of immunoglobulins (antibodies). They play a crucial role in the immune system by helping the body defend against pathogens.
what is vascoconstriction
Immediately after a blood vessel is injured, the smooth muscle in the vessel wall contracts, reducing blood flow to the area.
This vasoconstriction released platelet factors (like serotonin).
