Physiology Flashcards

1
Q

What is homeostasis

A

stable internal environment, essential for normal cell and body function

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2
Q

what does a disruption in homeostasis do

A

disease or death

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3
Q

what is the intrinsic system (generally)

A

local control in cell

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4
Q

what is the extrinsic system (generally)

A

regulatory mechanisms outside organ by nervous action or endocrine glands

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5
Q

what is positive feedback

A

amplifies initial change

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6
Q

what is negative feedback

A

main homeostatic control

it opposes the initial change by using a sensor, control centre and effector

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7
Q

what is feedforward

A

response made in anticipation to change

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8
Q

Name the vital signs

A
Heart rate 
oxygen saturation
blood pressure
capillary refill rate 
respiratory rate 
consciousness 
temperature
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9
Q

What is NEWS

A

National Early Warning System - chart used to record vitals

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10
Q

True/false - values on NEWS overrides clinical concern

A

FALSE - clinical concern and judgement will always override the news score

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11
Q

What else do you do besides vitals

A

Ask and observe how the patent is feeling

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12
Q

what is the sound heard in blood pressure

A

Korotkoff sounds

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13
Q

which korotkoff sound measures BP

A

the first sound meaurtes systolic pressure and the last muffled sound followed by an absence of sound measures the diastolic

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14
Q

What is blood pressure

A

hydrostatic pressure exerted by blood on blood vessel walls

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15
Q

Define systolic and diastolic

A

Systolic - pressure exerted by blood on blood vessel walls when heart contracts
Diastolic - pressure exerted by blood on blood vessel walls when heart relaxes

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16
Q

What is pulse pressure

A

difference between systolic and diastolic blood pressure

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17
Q

What is MAP

A

average arterial blood pressure during 1 cardiac cycle

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18
Q

How is MAP measured

A

[(2xDiastolic) + Systolic]/3

DBP + 1/3 pulse pressure

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19
Q

What is the minimum map to perfuse brain heart and kidneys?

what is the average MAP

A

60 mmHg

70-105 mmHg

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20
Q

what are baroreceptors and where are they located?

A

stretch sensitive receptors that depending on stretch cause impulses to be sent to NTS more or less
located on carotid artery and aorta

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21
Q

How is MAP calculated?

A

HR x SV x SVR

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22
Q

What is systemic vascular resistance

A

sum of resistance across all circulatory system vasculature

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23
Q

what neurotransmitter increases heart rate

A

noradrenaline

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24
Q

what neurotransmitter decreases heart rate

A

acetylcholine

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25
Q

how is stroke volume increased

A

sympathetic nerves further stimulate ventricular myocardium which causes it to increase contraction force

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26
Q

hormones regulate MAP in the _____

A

long term

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27
Q

what is normal core body temp

A

around 37.8C

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28
Q

what is normothermia

A

normal core body temp - optimum for cell metabolism and function

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29
Q

what ways can temperature be measured

A

Rectal (36.7-37.5) - most accurate
Tympanic (35.5-37.5) - most common
Oral - unreliable

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30
Q

what is basal metabolic rate

A

minimum energy required to sustain body function - hormonally influenced

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31
Q

what ways can heat be produced?

A

oxidation of food

movement of skeletal muscles - shivering and moving

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32
Q

Methods of heat exchange?

A

Conduction
Convection
Radiation
Evaporation

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33
Q

what detects heat gain or loss

A

central and peripheral thermoceptors

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34
Q

what effectors conserve or help to generate heat

A

skeletal muscles, arterioles and sweat glands

35
Q

What is the control centre for thermoregulation

A

Hypothalamus
Posterior hypothalamus for cold
Anterior hypothalamus for warmth

36
Q

Fever temperature

A

38-40C

37
Q

Hyperthermia temperature

A

uncontrolled rise above 40C

38
Q

Hypothermia temperature

A

under 35C

39
Q

Describe the mechanism of fever

A

chemicals released from macrophage acting as endogenous pyrogen - stimulating prostaglandins in hypothalamus
Prostaglandins reset core body temp to greater temperature to initiate posterior hypothalamus in cold response
cycle can be broken when pyrogen or prostagandins reduced or ceased. hypothalamus cools body back to normal set point

40
Q

What is the importance of cell membranes

A

Controls nutrient entry and exit of waste - selectively permeable
Differences in ion concentration
Joining cells to form tissues and organs
Allowing cells to respond to environmental signals

41
Q

What is the cell membrane composed of

A

Majority phospholipids

42
Q

What are phospholipids composed of

A

Glycerol backbone with polar head and phosphate group and 2 fatty acid tails

43
Q

The phospholipid bilayer is _______ and phospholipids are ____ in terms of movement

A

fluid

free

44
Q

What helps to stiffen the bilayer

A

Cholesterol

45
Q

True/false - water soluble molecules can easily diffuse across the cell membrane

A

False - it is difficult for water soluble molecules to get across the cell membrane with the exception of some uncharged polar molecules (oxygen, carbon dioxide and water

46
Q

Peripheral proteins

A

not embedded in membrane

adhere tightly to an extracellular surface

47
Q

Integral proteins

A

embedded in membrane

can be linked to lipid or fatty acid component

48
Q

Transmembrane proteins

A

spans the entire membrane

pores, carriers, channels, pumps

49
Q

What is the glycocalyx

A

short carbohydrate molecules that are bound to proteins and lipids

50
Q

What is a molecule passing through the cell membrane dependent on?

A

Solubility in lipid

Particle size

51
Q

Simple diffusion

A

Diffusion through lipid bilayer that will continue to dynamic equilibrium
if the substance is insoluble in lipid simple diffusion cannot occur

52
Q

What are the factors of fick’s law?

A
Magnitude of concn gradient 
Surface area of membrane 
Lipid solubility of substance 
Molecular mass
Diffusion distance - usually constant within body
53
Q

What is the electrochemical gradient

A

net effect of simultaneous electrical and concentration gradients

54
Q

What is the net rate of diffusion proportional to? (Q)

A

∆C x A x P

55
Q

What is osmolarity

A

concentration of osmotically active particles in a solution

56
Q

What is tonicity

A

effect a solution has on cell volume

57
Q

What are the characteristics surrounding carrier transport

A

Specificity
Saturation
Competition

58
Q

Primary active transport

A

energy required directly to remove substance against concn gradient

59
Q

Secondary active transport

A

carrier utilises energy from an ion concn gradient (sodium usually) - a driver force

60
Q

Symport

A

solute and sodium move in the same direction

61
Q

Antiport

A

solute and sodium move in opposite directions

62
Q

Sodium potassium pump

A

3 Na out and 2K in
Used in regulating cell volume
Energy used to drive the pump serves as an energy source for secondary active transport

63
Q

What is Em

A

membrane potential - the difference in charge between ECF and ICF

64
Q

What cells can produce membrane potential typically

A

Nerve and muscle

65
Q

What is the equilibrium potential for potassium and what does it rest at

A

-90mV

where there is no net movement of potassium out of cell by concn gradient or in by electrical gradient

66
Q

What is the nernst equation

A

Eion=61log x [ion]o/[ion]i

67
Q

What is the equilibrium potential for sodium and what doe sit rest at?

A

+60mV

68
Q

What is the overall resting membrane potential?

A

-70mV

69
Q

why is Em not equal to Ek?

A

there is an inward leak of sodium down the electrochemical gradient

70
Q

Why is the value of Em more negative than was thought to be?

A

potassium is more permeable to the membrane hence why it is more negative

71
Q

what is haemostasis

A

arrest of bleeding while keeping blood vessels open

72
Q

Stages of anticoagulation

A

platelet plug - primary haemostasis
fibrin clot - secondary haemostasis
fibrinolysis

73
Q

what do platelets release when bound to a wound to form a fibrin clot

A

calcium

74
Q

what tissue factor binds to phospholipid/platelet layer

A

VII

75
Q

what do factor V and X do

A

catalyse conversion of prothrombin to thrombin

76
Q

what does thrombin do

A

catalyses conversion of fibrinogen to fibrin, which acts on factor VIII/ IX to form a fibrin clot

77
Q

single clotting factor deficiency

A

hemophilia

hereditary

78
Q

multiple clotting factor deficiencies

A

Acquired generally

Disseminated intravascular coagulation

79
Q

What is fibrinolysis

A

plagminogen is converted to plasmin by TPA - plasmin breaks fibrin into fibrin degradation products

80
Q

how do serine protease inhibitors act as anticoagulants

A

produces anti thrombin III which inhibits action and production of thrombin and therefore factor VII, V, X, VIII, IX

81
Q

how do PC/PS act as anticoagulants

A

activated by thrombin and acts on factors V, X, VIII, IX to inhibit further clot formation

82
Q

What is arterial thrombosis and how is it treated

A

caused by atherosclerosis build up and forms a platelet rich thrombus
Treated with aspirin and anti platelet drugs - risk factors for atherosclerosis modified

83
Q

What is venous thrombosis and how is it treated

A

low pressure system with no platelets activated so cascade of coagulation due to inactivity, fibin rich
Can cause PE and DVT
Treated with heparin and warfarin

84
Q

what is virchows triad

A

risk factors for venous thrombosis

stasis, vessel wall injury, hypercoagulability