circulatory system

Question 1

artery composition

Answer 1

endothelium
elastic tissue
smooth muscle
fibrous tissue

Question 2

vein composition

Answer 2

endothelium
elastic tissue
smooth muscle
fibrous tissue

Question 3

blood composition

Answer 3

92% Water
7% Protein
1% Dissolved organic molecules

Question 4

arteriole composition

Answer 4

endothelium
smooth muscle

Question 5

capillary composition

Answer 5

endothelium

Question 6

venule composition

Answer 6

endothelium
fibrous tissue

Question 7

Erythropoiesis

Answer 7

process of producing red blood cells (erythrocyte) in the body
occurs in the bone marrow

involves erythropoietin (EPO) : glycoprotein hormone
AND cytokines which are produced in the kidney

trigger for EPO to be released is hypoxia

Question 8

EPO mechanism

Answer 8

Erythropoietin acts on erythroid progenitor (precursor RBCs) cells in the bone marrow
–> causes proliferation (cell division), differientationan and matruation
–> erythrocytes (produces RBC)

produce erythrocytes == increase the oxygen-capacity in the blood

Question 9

blood doping

Answer 9

1. blood transfusions : INCREASE in RBCS
2. injection of EPO
3. injection of oxygen carriers : act as RBCs

Question 10

mechanism of heart contraction

Answer 10

1. Late diastole : all chambers are relaxed, ventricles filled passively
   –> sinoatrial node/ SA node in right atrium : generates electrical impulses to initiate the heartbeat by depolarization of cardiac muscle cells

–> the electrical implulses reach the AV node through the internodal pathways
2. Atrial systole : atrium contract blood
–> atrioventricular node / AV node delays the electrical impulse for atria to fully contract and ventricles filled with blood (regulates heartbeat)

–> signal travels through the Bundle of His
–> divide into smaller fibers called Purkinje fibers along the ventricles

3. isovolumic ventricular contraction : the AV valves are closed so the pressure builds in the ventricles but the semilunar values still closed, pressure not strong eough to open them yet
4. ventricular ejection : once the pressure is high enough, the semilunar valves open and blood is ejected
5. isovolumtc ventricular relaxation: ventricle relaxes (V increase, P decrease) thus semilunar valves close

Relaxation = diastole

Question 11

stroke volume

Answer 11

the volume ejected for each contraction
ml/beat
e.g 70ml/beat

Question 12

CO

Answer 12

cardiac output = SV x HR
= 70ml/beat * 72bpm = 5.4 L/min

Question 13

120/80 what do these numbers mea

Answer 13

120 is systolic pressure
80 is diastolic pressure

Question 14

postural hypotension

Answer 14

blood pools in the feet when we’re not moving
causes a decrease in blood pressure
inadequate flow of blood to the brain

Question 15

capillary transport

Answer 15

Three mechanisms of exchange
– Movement between endothelium
~ small molecules (e.g CO2, O2) diffuse through the lipid bilayer of the endothelial cells/ pass through intercellular clefts (gapes)
– Transcytosis (type of endoctyosis)
formation of vesicles within the endothelial cells that engulf the molecules from one side of the cell membrane and release them on the other side.
– Bulk flow
similar to diffusion except down pressure gradients and less selective