Physiology Flashcards

1
Q

what are the levels of organisation in physiology?

A

cells > tissues (a group of similar structure and specialised function) > body organs (made up of 2 or more types of primary tissue that function together to perform particular functions

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2
Q

what is a body system?

A

a group of organs that perform related functions and work together to achieve a common goal. systems work in harmony and are highly sophisticated

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3
Q

what must the body maintain to remain healthy?

A

highly regulated optimum physiological conditions

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4
Q

what is human physiology?

A

the study of normal functions of the human body and the integrative mechanisms that control them.

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5
Q

what is physiology essential for in a clinical setting?

A

understanding the body function in health and disease
understanding the patient presentations
planning and interpretation of patient investigation
planning patient management options
providing health promotion and disease prevention advice

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6
Q

in the cell where does a lot of physiological control occur?

A

the membrane

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7
Q

what is the change in membrane potential?

A

the voltage across the membrane between the inside and the outside of a cell

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8
Q

what is the membrane potential important for?

A

the functionality for nerve and muscle cells

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9
Q

what level do many pharmacological agents act at?

A

level of cell membrane to produce their therapeutic effect

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10
Q

what is homeostasis?

A

the maintenance for a stable internal environment by coordinated physiological mechanisms. several variables within the internal environment must be tightly regulated within a narrow niche

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11
Q

what are physiological control systems important for maintaining?

A

homeostasis

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12
Q

what are the two desired responses that physiological control systems produce?

A

intrinsic controls and extrinsic controls

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13
Q

what are intrinsic controls?

A

local controls that are inherent in an organ

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14
Q

what are extrinsic controls?

A

regulatory mechanisms initiated outside an organ

accomplished by nervous and endocrine systems

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15
Q

what is a feedforward response?

A

responses made in anticipation of a change

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16
Q

what is a feedback response?

A

responses made after change has been detected

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17
Q

what are the type of feedback systems?

A

positive: amplifies an initial change
negative: opposes an initial change (main type)

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18
Q

what is the primary type of homeostatic control mechanism?

A

negative feedback

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19
Q

what are core temperature and blood glucose regulated by?

A

negative feedback mechanisms

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20
Q

what must a negative feedback control system be able to do, to maintain homeostasis?

A
sense deviations (sensor) from desired range in a regulated variable that needs to be kept within a narrow range (set point)
integrate information with other relevant information (control centre)
make appropriate adjustment (effectors) in order to restore regulated variable to its desired range (set point)
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21
Q

what is blood pressure?

A

outwards (hydrostatic) pressure exerted by the blood on blood vessel walls. often measure the systemic arterial blood pressure and express it as systolic and diastolic blood pressures.

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22
Q

what is systemic systolic arterial blood pressure?

A

the pressure exerted by the blood on the walls of the aorta and systemic arteries when the heart contracts

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23
Q

what is the systemic diastolic arterial blood pressure?

A

pressure exerted by the blood on the walls of the aorta and systematic arteries when the heart relaxes

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24
Q

what is the normal systemic arterial blood pressure?

A

between 120/80 and 90/60, this varies between individuals

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25
Q

what is hypertension?

A

high blood pressure, clinical blood pressure of 140/90 mmHg or higher, daytime blood pressure 135/85 mmHg or higher

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26
Q

which way round do the systolic and diastolic numbers go?

A
systolic = top
diastolic = bottom
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27
Q

what is pulse pressure?

A

pulse pressure is the difference between the systolic and diastolic blood pressures. usually between 30 and 50 mmHg

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28
Q

what is the mean arterial blood pressure (MAP)?

A

the average arterial blood pressure during a single cardiac cycle which involves the contraction and relaxation on the heart.

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29
Q

True of false, the systolic portion is twice as long as the diastolic portion

A

false - the diastolic portion is twice as long as the systolic

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30
Q

what is the simplest way to estimate MAP?

A

[(2x diastolic) + systolic] / 3 or DBP +1/3 of pulse pressure

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31
Q

what value should MAP be in order to perfuse vital organs like brain, heart and kidneys?

A

at least 60mmHg. must be regulated within a narrow range to ensure pressure is high enough to perfuse vital organs but not too high to damage the blood vessels or place a strain on the heart and other organs

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32
Q

what are baroreceptors?

A

mechanoreceptors which are sensitive to stretch

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33
Q

what are two important baroreceptors?

A

carotid and aortic baroreceptors

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34
Q

what happens to the firing rate in baroreceptors afferent neutrons when the mean arterial blood pressure increases/decreases?

A

increases when MAP increases

decreases when MAP decreases

35
Q

where do baroreceptors send afferent impulses to?

A

the cardiovascular control centre in the medulla of the brain stem

36
Q

what are the sensors, control centre and effectors in the baroreceptor reflex?

A

sensor: baroreceptors
control centre: cardiovascular control centre (medulla)
effector: heart and blood vessels

37
Q

what is the systemic vascular resistance?

A

sum of resistance of all vasculature in the systemic circulation

38
Q

what is the cardiac output?

A

the volume of blood pumped by each ventricle of the heart per minute

39
Q

what is the stroke volume?

A

the volume of blood pumped by each ventricle per heart beat

40
Q

what can the mean arterial blood pressure be regulated by?

A

heart rate, stroke volume and systematic vascular resistance

41
Q

how does the heart pump blood?

A

electrically controlled muscular pump which sucks and pumps blood

42
Q

what is autorhythmicity?

A

when the heart beats rhythmically in the absence of external stimuli

43
Q

how is heart rate modified?

A

by the autonomic (involuntary) nervous system (ANS)

44
Q

what does sympathetic division stimulation do to heart rate?

A

increase heart rate (tachycardia)

45
Q

what does parasympathetic division stimulation do to heart rate?

A

decrease heart rate (Brady cardia)

46
Q

what happens to the stroke volume if the contractile strength of the heart increases?

A

increases

47
Q

what regulates stroke volume?

A

autonomic system

48
Q

what is SVR regulated by?

A

vascular smooth muscle

49
Q

what happens when vascular smooth muscle contracts?

A

causes vasoconstriction and increases SVR and MAP

50
Q

What happens when vascular smooth muscle relaxes?

A

causes vasodilation and decreases SVR and MAP

51
Q

what is vasomotor tone?

A

when vascular smooth muscle are partially constricted at rest caused by discharge of sympathetic nerves resulting in continuous release of noradrenaline

52
Q

what is noradrenaline?

A

acts on B1 receptors

53
Q

what is acetylcholine?

A

acts on muscarinic receptors

54
Q

what happens when sympathetic discharge increases?

A

vasomotor tone will increase, vasoconstriction will increase, SVP and MAP will increase

55
Q

what do baroreceptors respond to?

A

acute changes in arterial blood pressure

56
Q

what happens if high arterial blood pressure is sustained?

A

baroreceptors firing decreases

57
Q

in the long term what is MAP controlled by?

A

blood volume via hormones

58
Q

what are commonly assessed vital signs?

A

pulse , blood pressure, respiratory rate, oxygen saturation temperature
consciousness, capillary refill time

59
Q

why is skin not a good site for monitoring temperature?

A

temperature varies more widely

60
Q

what’s normothermia?

A

when the normal core body temperature is kept within a narrow range. optimum for cellular functions and metabolism

61
Q

what does increasing body temperature to cellular metabolism?

A

increases it

62
Q

how is temperature measured in clinical practice?

A

infrared tympanic thermometer

63
Q

what is a very low temperature called?

A

hypothermia

64
Q

what is diurnal variation in body temperature?

A

body temperature varies throughout the day, lowest temperature in early morning

65
Q

what is basal metabolic rate (BMR)?

A

the minimum amount of energy required to sustain the vital body functions

66
Q

how can your BMR be increased?

A

by hormones such as adrenaline

67
Q

how does shivering increase heat production?

A

by increasing muscle activity

68
Q

how much of the bodies heat is out through radiation?

A

around half

69
Q

what does heat conduction mean for the body?

A

heat moves from warmer to cooler objects, heat conduction depends on temperature gradient and thermal conductivity

70
Q

what does convection mean for the body?

A

transfer of heat energy by air (or water) currents that help to carry heat away from the body

71
Q

what does evaporation mean for the body?

A

energy is required to convert water in the skin surface and lining of the respiratory airways into vapour, sweating is an active evaporative heat loss process controlled by the sympathetic nervous system

72
Q

what are the sensors, control centre and effectors for the negative feedback in temperature control?

A

sensors: central thermoreceptors, peripheral thermal receptors
control centre: hypothalamus
effectors : skeletal muscles, skin arterioles, sweat glands

73
Q

what is the body thermostat?

A

hypothalamus

74
Q

what is the anterior/posterior hypothalamus activated by?

A

posterior - cold

anterior - warmth

75
Q

what’s the difference between shortness of breath acute and chronic?

A

acute - comes on suddenly and unexpectedly

chronic - comes on gradually

76
Q

why do we need to breath?

A

our body system is made of cells, the cells need a constant supply of oxygen to produce energy, the carbon dioxide produced by cellular reactions must be removed from the body

77
Q

what are some causes of shortness of breath?

A

respiratory, cardiovascular, physiological, haematological, psychological, endocrine and metabolic causes

78
Q

why with the diastolic arterial pressure not fall to zero during diastole?

A

elastic recoil of the aorta and large arteries and the intact aortic valve

79
Q

what are the two main factors that affect extracellular fluid volume?

A

water recess or deficit and Na+ excess or deficit

80
Q

what is the ECF volume?

A

the plasma fluid and the interstitial fluid, the fluid that the cells bathe in and acts as a go-between the blood and body cells

81
Q

what happens if the plasma volume drops?

A

compensatory mechanisms shift fluid from the interstitial compartment to the plasma compartment

82
Q

what regulates extracellular fluid volume?

A

hormones that act as effectors by regulation the water and salt balance in our bodies. water input should equal water output

83
Q

what hormones regulated extracellular fluid volume?

A
the Renin-Angiotensin-Aldosterone System 
natriuretic peptides (NPs) 
antidiuretic hormones (arginine vasopressin)