Blood & Vessels Flashcards
What are the 3 types of blood cells?
- RBC
Transport & regulation - WBC
Protection
PLASMA
Intracellular substance of blood
What is haemostasis?
Clotting
The sequence of events that stops bleeding from a damaged blood vessel
What is a haematocrit?
The percentage of blood that is composed of RBC
What are the formed elements of blood & their major functions?
RBC - carry oxygen
WBC - immunity
Platelets - clotting
What are the 3 components of blood plasma?
water
proteins
- albumin
- maintain blood osmotic pressure
- globulins
- fibrinogen
solutes other than proteins
- electrolytes
- nutrients
- gases
- vitamins & wastes
What is haemopoiesis? Where does it occur?
Process which formed elements develop.
Before birth - occurs in liver, spleen, thymus & lymph nodes of a foetus
Last trimester & beyond - occurs in red bone marrow
What is the structure of an erythrocyte & what do they contain?
- biconcave disc
- lack of nucleus & other organelles
- consists of a plasma membrane, cytosol & haemoglobin
What is haemoglobin & what does it do?
- protein complex
- contains pigment called ‘haeme’ that binds to iron
- transports approx 13% of CO2
What is erythropoiesis?
Production of RBCs
What hormone controls erythropoiesis?
EPO - erythropoietin
- hormone that stimulates RBC production
- secretion increases in response to decreased blood oxygen level
- released by the kidneys
How are old & damaged RBCs removed from the blood?
- macrophages
- haemoglobin broken down
- iron recycled
What are WBCs & how are they classified?
- immune cells
- granular or agranular
What are the 5 types of WBCs?
GRANULAR
- neutrophils
- eosinophils
- basophils
AGRANULAR
- monocytes
- lymphocytes
GRANULAR WBCs
EOSINOPHILS
- anti inflammatory
- phagocytise antigen-antibody complexes
- attach parasitic worms
BASOPHILS
- releases histamine
- stimulate inflammation
- involved in allergic reaction
NEUTROPHILS
- attack bacteria & fungi
- release anti-microbial chemicals
AGRANULAR WBCs
MONOCYTES
- develop into macrophages & phagocytise microbes
- clean up cellular debris a following damage
LYMPHOCYTES
- B cells differentiate into cells that produce antibodies
- T cells attack viruses, cancer
- NK cells attack various infections, microbes & cancers
What are platelets?
- thrombocytes
- cell fragments
What are the 3 stages of haemostasis?
- vascular phase
- platelet phase
- coagulation phase
What activates blood clotting?
- clotting factors activated prothrombin is formed
- converted to thrombin
- thrombin converts fibrinogen to insoluble fibrin threads
- fibrin traps cells, platelets & fluid
What is the clot reaction?
- tightening of a fibrin clot
- platelets contract, pulls edges of damaged vessel together
- fibroblasts begin forming connective tissue over captured area
- new cells arise & vessel lining is repaired
What is fibrinolysis?
- breaking down or dissolving of blood cells
- fibrin is broken down
What are the ABO blood groups?
A
Surface antigen A only
Plasma contains anti- B antibodies
B
Surface antigen B only
Plasma contains anti- A antibodies
AB
Surface antigen A&B
Neither anti-A or anti-B antibodies
O
Lack both A&B surface antigens
Plasma contains both anti-A & anti-B antibodies
What are the Rh groups?
Rh positive
- RBC has the rhesus antigen
Rh negative
- RBC does not have the rhesus antigen
What are the main function of blood vessels?
- transport materials around the body
- carry nutrients to cells
- carry wastes away for excretion
- regulates BP & blood flow
- vasoconstriction & dilation
What are the 3 functions of blood?
- transportation
- regulation
- protection
What are the 2 different circuits of blood vessels?
PULMONARY
carries blood from the heart, to the lungs & back to the heart
SYSTEMIC
carries blood from the heart to the rest of the body & back to the heart
What are the 2 main systems of blood vessels?
ARTERIAL
Carries blood away from the heart
VENOUS
Carries blood to the heart
Blood vessels of the ARTERIAL system
ARTERIES
- carry blood away from the heart
- branch off into smaller & smaller arteries
ARTERIOLES
- connect arteries to capillaries
CAPILLARIES
- smallest vessels
- major site of exchange for nutrients, gas, wastes between blood vessels & tissues
Blood vessels of the VENOUS system
VENULES
- small vessels that connect to capillaries
- some molecules exchange
- merge with veins
VEINS
- carry blood towards the heart
- merge together to become large & larger
What is the general circulatory route of blood?
Heart Arteries Arterioles Capillaries Venules Veins Heart
What are the 3 main types of arteries & their main features?
ELASTIC ARTERIES
can handle larges fluctuations in BP
MUSCULAR ARTERIES
regulate blood distribution
SMALL ARTERIES
thinner walls
What are the 3 layers of arterial walls?
- tunica intima
- tunica media
- tunica externa
What is capillary exchange?
- movement of substances between blood & interstitial fluid
- at the arterial end of capillary, fluid leaves to go in to into interstitial fluid
- at venous end of a capillary fluid comes back in to the capillary
What 2 pressures effect capillary exchange?
Blood hydrostatic pressure
- pressure of blood pushing on to the vessel wall (capillary BP)
Colloid osmotic pressure
- concentration of solute a affects movements of water by osmosis
- blood is more concentrated then the interstitial fluid
What is vascular resistance & how is it related to BP?
Opposition to blood flow due to friction between blood & walls of vessels.
- increase in resistance, higher BP
- decrease in resistance, lower BP
What 3 factors effect vascular resistance?
Size of the lumen
- larger the lumen diameter, less resistance
Blood viscosity
- thinner blood = less resistance
Vessel length
- shorter length less resistance
