vasculature and blood cells

Question 1

what is vasculature

Answer 1

network of blood vessels in the body or within an organ

Question 2

types of blood vessels

Answer 2

arteries, veins and capillaries

Question 3

where does the gas exchange happen

Answer 3

in capillary bed (O2 and CO2)

Question 4

layers of an artery and a venule

Answer 4

tunica interna (intima), tunica media and tunica externa (tunica adventitia)

Question 5

what type of cells line the lumen

Answer 5

endothelium

Question 6

what forms the tunica interna (intima)

Answer 6

layer of epithelial cells (endothelium)

Question 7

what forms the tunica media

Answer 7

smooth muscle and elastic tissue

Question 8

what forms the tunica externa (tunica adventitia)

Answer 8

connective tissue

Question 9

what is the difference between the layers of arteries and venules

Answer 9

tunica media in arteries:

• thicker because it has to pump blood around body
• less elastic fibres, mostly smooth muscle
• small lumen compared to wall thickness

Question 10

what happens if arteries are constricted

Answer 10

blood pressure goes up

Question 11

what is an anastamosis

Answer 11

point where 2 blood vessels join/merge

there is communication between arterial branches

Question 12

what is the advantage of anastomosis

Answer 12

it gives an alternative route for blood supply if one fails - collateral circulation

Question 13

what is the circle of willis

Answer 13

anastomoses at the base of the brain - very important for brain blood supply - blood can come from another vessels if one is blocked

Question 14

what is atherosclerosis

Answer 14

an inflammatory disease where cholesterol enters the vessel wall - build up of fat in the vessel wall

Question 15

what are the consequences of atherosclerosis

Answer 15

it narrows lumen and render wall less elastic
more resistance to blood
less blood circulation
myocardial infarction or stroke

Question 16

what causes myocardial infarction or stroke

Answer 16

fat particles on the vessel wall fall off and get into the bloodstream - can cause a blockage - embolia

Question 17

what are capillaries

Answer 17

smallest blood vessels, exchange vessels

Question 18

wall of capillaries

Answer 18

only tunica intima:

single layer of endothelial cells and basement membrane - this makes them very permeable for gas exchange

Question 19

the 3 structural type of capillaries

Answer 19

continous, fenestrated and sinusoid

Question 20

characteristics of continuous capillaries

Answer 20

complete basement membrane 
endothelial layer (tunica intima) has intercellular clefts to allow proteins in

Question 21

characteristic of fenestrated capillaries

Answer 21

complete basement membrane
fenestrations in endothelial layer
in kidneys and luver for nutrient exchange

Question 22

characteristics of sinusoid capillaries

Answer 22

incomplete basement membrane intercelular

Question 23

two types of venules

Answer 23

post capillary and muscular

Question 24

characteristics of post capillary venules

Answer 24

smallest, 
no tunica media, 
sparse tunica externa
very porous
site of white blood cell migration

Question 25

characteristics of muscular venules

Answer 25

microscopic tunica media 1-2 layer of smooth muscle sparse tunica externa no more exchange with interstitial fluid

Question 26

how is pressure in veins

Answer 26

low pressure

Question 27

layers of veins

Answer 27

large lumen | poorly developed tunica media

Question 28

what causes varicose veins

Answer 28

vein walls loose elasticity -> they weaken and dilate incompetent valves so backflow can't be prevented abnormal blood flow so veins dilate even more

Question 29

what is blood

Answer 29

the fluid of the circulatory system (plasma and cells)

Question 30

functions of blood

Answer 30

1. transportation: nutrients and waste (co2) 2. protection: immune system 3. regulation: hormones, proteins, etc

Question 31

what is haematopoiesis

Answer 31

blood production

Question 32

what is haemorrhaging

Answer 32

blood loss

Question 33

blood components (4)

Answer 33

1. red blood cells (erythrocytes) 2. white blood cells (eukocytes) less than 1% 3. platelets (thrombocytes) involved in clotting - block a leakage 4. plasma

Question 34

where are blood cells produced

Answer 34

in bone marrow (inner bone) and in kidney

Question 35

what forms the red blood cells

Answer 35

haemoglobin protein | no nucleus

Question 36

what is anaemia

Answer 36

low number of erythrocytes - low iron

Question 37

functions of white blood cells (leukocytes)

Answer 37

protection and phagocytosis

Question 38

major classes of leukocytes

Answer 38

1. granulocytes: neutrophils, eosinophils and basophils | 2. agranulocytes: lymphocytes and monocytes

Question 39

abnormal leukocyte levels

Answer 39

leukopenia: low white blood cell count -> infection leukocytosis: high white blood cells -> inflammation

Question 40

what are platelets (thrombocytes)

Answer 40

cell fragments which control blood loss

Question 41

platelet counts

Answer 41

normal: 150,000-450,000 platelets/uL thrombocytosis: >450,000 - blood test thrombocytopenia: <150,000 - they'll bleed out and take longer to clot

Question 42

what is plasma

Answer 42

is the straw-coloured liquid in which the blood cells are suspended half of our blood is made of plasma

Question 43

composition of plasma

Answer 43

1. water: 92% 2. proteins - major protein= albumin involved in water regulation 3. glucose 4. electrolytes