Lecture 11 - Blood vessels and coronary circulation

Question 1

2 types of blood vessels

Answer 1

elastic arteries and muscular arteries

Question 2

what are elastic arteries

Answer 2

arteries that originate from the heart itself - aorta pulmonary

Question 3

muscular arteries

Answer 3

more distal - artery, arterioles

Question 4

transverse section of artery

Answer 4

lumen, endothelium, tunica intima, media and adventitia,

Question 5

Internal elastic lamina

Answer 5

layer between intima and media

Question 6

external elastic lamina

Answer 6

layer between media and adventitia

Question 7

What is the difference between elastic and muscular artery

Answer 7

elastic artery has a bigger lumen and tunica media is a lot thicker in muscular artery

Question 8

what does the tunica media contain and why is it important

Answer 8

it contains a lot of vascular smooth muscle and it is important because it is vital in constriction and relaxation.

Question 9

blood supply to elastic artery and muscular artery

Answer 9

has its own blood supply but more distally in circulation, more dependent on diffusion

Question 10

laminar flow

Answer 10

in a parabolic shape, central lumen, velocity is quicker and sides slower. resistance and heat is produced due to contact with endothelium at the sides.

Question 11

turbulent

Answer 11

not uniform. occurs during pathologies. can be caused due to atherosclerosis, branch points in blood vasculature and narrowed valve (aortic stenosis), will hear a murmur.

Question 12

why would laminar flow become turbulent?

Answer 12

in normal physiological states, in laminar flow, perfusion pressure and flow has a linear relationship. higher perfusion pressure, higher drive, higher flow. flow is reduced in turbulent flow.

Question 13

what is reynolds number?

Answer 13

threshold at which laminar flow becomes turbulent

Question 14

how can you observe flow in vessels?

Answer 14

injecting due during early systole.scattered due - turbulent

Question 15

Flow is determined by 2 key phenomenon

Answer 15

difference in pressure (between left ventrical - highest and right atrium-lowest) and resistance (proportional to radius to the power 4)

Question 16

What is the difference between flow and velocity

Answer 16

flow - volume of blood moved in a given period of time

velocity - speed of flow

Question 17

Flow formula

Answer 17

velocity x cross sectional area

Question 18

Total cross sectional areas in vessels

Answer 18

capillaries have the highest cross sectional area to diffuse properly followed by venules and arterioles. lowest in aorta and vena cava

Question 19

where is the velocity highest?

Answer 19

aorta and then arteries. lowest in capillaries.

Question 20

Blood flow is directly proportional to

Answer 20

pressure gradient (left ventricular and right atrial difference)

Question 21

blood flow is inversely proportional to

Answer 21

resistance

Question 22

what parameters determine resistance

Answer 22

length of blood vessel
radius of vessel ultimately determines
eta - viscosity of blood

Question 23

flow equation

Answer 23

flow= delta P/R

Question 24

Pulse pressure

Answer 24

difference between systolic and diastolic pressure

mostly 40 mm/hg

Question 25

Mean pressure

Answer 25

diastolic pressure + 1/3rd of pulse pressure around 93 80+ 13

Question 26

Active hyperaemia

Answer 26

increase in local blood flow in response to a local metabolic activity. may be mediated by chnages in conc of many substances in interstitial fluid - O2, CO2, K and H+

Question 27

Vascular endothelium produces

Answer 27

prostacyclin and nitric oxide - vasodilators

Question 28

Endothelium derived relaxing factor

Answer 28

Nitric oxide - released by endothelial cells on a continuous basis in response to chemical signals

Question 29

importance of nitric oxide

Answer 29

key mediator in vascular function, anti-atherosclerotic effects, anti-inflammatory

Question 30

nitric oxide is mediated by?

Answer 30

by an increase in intracellular calcium

Question 31

how is nitric oxide produced?

Answer 31

arginine is converted to citrulline and nitric oxide is produced in the process. migrates smooth muscle and activates guanlyl cyclase and converts GTP to cGMP and causes relaxation

Question 32

Where does the right and left coronary arteries originate from?

Answer 32

in the coronary sinuses at the bottom of the aorta

Question 33

where is the cardiac vein

Answer 33

runs parallel with the LAD

Question 34

what are the veins of the heart

Answer 34

small, middle and great cardiac vein which drains into the coronary sinus, drains into the right atrium

Question 35

atheroma formation

Answer 35

within lumen of the vessel.

Question 36

pathophysiology of atheromatous disease

Answer 36

atheroma is early initiator of atherosclerosis. with time, there is a increase in lipid deposits. this activates macrophages and forms foam cells. activates immune system, pro-inflammatory environment results in vascular smooth muscle proliferation. this surrounds lipid deposit. this is called a fibrous cap. can cause angina on exertion.

Question 37

acute coronary syndrome

Answer 37

acute plaque rupture of fibrous cap that has been developing for a long time. exposure of the collagen stimulates the formation a thrombus. can cause occlusion of the vessel.

Question 38

Pathologies in ECG in MI

Answer 38

ST segment elevation