introduction to c&b

Question 1

what is pressure and its units

Answer 1

pressure= force/area
units= either pascal, atmosphere or mmHg

Question 2

what is 1 atmosphere equivalent to

Answer 2

1atm= 101.325kPa

Question 3

what is absolute pressure

Answer 3

• includes atmospheric pressure
• atmospheric pressure at sea level is 1
• partial pressures of oxygen at sea level 21% of 101.325kPa= 21.23kPa

Question 4

what is guage pressure

Answer 4

• does not include atmospheric pressure
• usually is above atmospheric pressure- looks at difference of pressure
• measurment of pressures in the body is guage pressure e.g. blood pressure
• so if systollic pressure is 120 that is 120 above atmospheric pressure

Question 5

what is volume measured in

Answer 5

• cm^3
  -ml
  -L

Question 6

what is boyles law

Answer 6

• decrease in volume causes an increase in pressure of gases
• graph is a negative reciprocal graph

Question 7

in liquids can pressure be exerted without a change in volume

Answer 7

yes

Question 8

what are the two types of flow

Answer 8

• turbulent flow- creates heart mummers
• laminar flow

Question 9

what are the factors that affect flow

Answer 9

• resistance is inversely proportional to flow
• increase in resistance decrease in flow

Question 10

flow equation

Answer 10

flow= change in pressure/resistance

Question 11

what affects resistance

Answer 11

• radius- increased radius decreased resistance
• viscosity- increased viscosity increased resistance
• vessel length- increased length increased resistance

Question 12

hagen-poiseullie equation

Answer 12

q= (change in pressure.r^4.π)/ (µ.L.8)

Question 13

in clinical situations what can we alter to change resistance

Answer 13

• radius of vessels
• dont really change viscosity or length as its harder to change

Question 14

what is the relationship between flow and radius

Answer 14

• flow is proportional to radius^4
• postive reciprocal graph

Question 15

what is cardiac output

Answer 15

• flow
• the volume of blood the heart pumps out in one minute

Question 16

what are the two equations for cardiac out put

Answer 16

co= stroke volume x heart rate
co= (map- rap)/ tpr(resistance)

Question 17

what is the equation for mean arterial pressure

Answer 17

MAP= DP + 1/3( sp-dp)

Question 18

across the peripheral cardiovascular system what changes and what stays the same

Answer 18

• pressure drops
• flow stays the same
• resistance changes

Question 19

why is decreased flow important and what are its clinical consequences

Answer 19

• decreased flow= less blood reaching tissues and therefore less oxygen
• cells need oxygen to undergo respiration
• decreased oxygen delivery= artherosclerosis
• no oxygen delivery= pulmanory embolus

Question 20

in terms of pressure how does inhalation happen

Answer 20

• during inhalation
• pressure outside is greater than pressure in lungs
• creates a pressure gradient and therefore air flows in

Question 21

in terms of pressure how does exhalation happen

Answer 21

• pressure in lungs is greater than pressure outside
• pressure gradient created this causes air to flow out from high pressure to low pressure

Question 22

what pressure does the lungs create

Answer 22

• negative pressure which allows air to flow into lungs from atmospheric pressure

Question 23

is inhalation, exhalation active or passive

Answer 23

inhalation- active
exhalation- passive

Question 24

how deos resistance in lungs affect air flow

Answer 24

• decreased diameter of airways increases reisistaance and therefore decreases flow in both inspiratory and expiratory

Question 25

what is compliance

Answer 25

refers to the vessel’s ability to respond to pressure changes by increasing or decreasing its volume
- something which is more compliant would stretch/change its volume more easily when theres small changes in pressure
- something which is less compliant would need large pressure changes to change its volume/ expand its vessel

Question 26

out of arteries, veins and hardened arteries what are the most compliant and what are the least

Answer 26

• veins most compliant
• arteries low
• hardened arteries- really low

Question 27

what is compliance affected by

Answer 27

• resistance to flow
• stiffness of system