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Y1 PRINCIPLES > Physiology > Flashcards

Physiology Flashcards

1
Q

Define ‘homeostasis’…

A

Maintenance of steady states within our bodies by coordinated physiological mechanisms

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2
Q

Main type of homeostatic control in the body…

A

Negative feedback

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3
Q

What are the components of a phospholipid?

A

Hydrophobic tail + hydrophilic head

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4
Q

Bonds between phospholipids are strong. True/False?

A

False

Bonds are weak - explains the fluid nature of the membrane

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5
Q

Cholesterol contributes to which two aspects of the membrane?

A

Fluidity and stability

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6
Q

What are the 3 main types of proteins found on the membrane?

A

Integral (receptors)
Transmembrane (channels, transporters)
Peripheral (enzymes)

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7
Q

The glycocalyx layer is formed by…

A

Short carbohydrate chains bound to proteins and lipids

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8
Q

What are desmosomes?

A

Adhering junctions that anchor cells together

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9
Q

What are tight junctions?

A

Join lateral edges of epithelial cells near their apical membranes

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10
Q

What are gap junctions?

A

Communicating junctions that allow movement of charge between adjacent cells

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11
Q

2 main factors that influence whether a particle can passively permeate the membrane

A 
Lipid solubility (non-polar pass easily) 
Size
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12
Q

Diffusion is movement from ___ to ___ concn

A

High to low

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13
Q

Fick’s law of diffusion describes the rate of net diffusion and is made up of…

A

Magnitude of concn gradient
SA available for diffusion
Lipid solubility and size/weight of substance
Distance over which diffusion must occur

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14
Q

Osmolarity is defined as…

A

The number of osmotically active particles present in a solution

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15
Q

How is osmolarity calculated?

A

Using molar concn (mM) and number of osmotically active particles (n)

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16
Q

150mM NaCl has osmolarity = ?

A

150 x 2 (Na+ and Cl-) = 300mOsm

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17
Q

A hypotonic solution will ____ in cell volume
A hypertonic solution will ____ in cell volume
A isotonic solution will ____ in cell volume

A

Increase (needs mOre water)
Decrease (needs lEss water)
Have no change

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18
Q

Facilitated diffusion requires energy. True/False?

A

False

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19
Q

Active transport transfers a substance from high to low concn. True/False?

A

False

Low to high

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20
Q

_ Na+ out for every _ K+ in with regards to Na-K pump

A

3, 2

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21
Q

Secondary active transport occurs by which 2 mechanisms? Define them

Primary active transport uses…

A

Utilises conc. gradient and ion movement:
Symport (co-transport): solute and ion move in same direction
Antiport: solute and ion move in opposite directions

ATP directly for energy

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22
Q

Membrane potential (Em) arises due to…

A

Separation of opposite charges across the membrane

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23
Q

At resting potential, the membrane is 100x more permeable to sodium than potassium. True/False?

A

False 100x more permeable to K+ than Na+

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24
Q

Em for K+ is approx…

A

-90mV

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25
Q

Em for Na+ is approx…

A

+60mV

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26
Q

Nernst equation

A

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

extracellular/intracellular conc.

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27
Q

Membrane potential is much closer to the potential of Na+ ions. True/False?

A

False

Much closer to Ek+ due to greater permeablity of K+

28
Q

Em for a typical nerve cell at rest = ?

A

-70mV

29
Q

GHK equation (used to calculate membrane resting potential)

A

Em = 61log x PK+[K+]o + PNa+[Na+]o /

PK+[K+]i + PNa+[Na+]i

30
Q

Normal blood glucose level

A

Around 5 mmol/l

31
Q

In the absorptive + post-absorptive states, which hormones control [glucose]p

A

Insulin and glucagon

32
Q

In emergencies, which hormone control [glucose]p

What is it released by?

A

Adrenaline

Released by adrenal gland

33
Q

In starvation, which hormones control [glucose]p

What are they released by?

A

Cortisol - Released by adrenal gland,

GH - Released by anterior lobe of the pituitary

34
Q

In pancreatic islet cells, _ cells release glucagon, _ cells release insulin and _ cells release somatostatin

A

alpha, beta, delta

35
Q

Insulin lowers [glucose]p by…

A

Stimulating uptake of glucose by muscle and fat cells Activating liver enzymes to convert glucose into glycogen
HARMONE OF FED STATE

36
Q

Diabetics can increase GLUT4 expression by doing what?

A

Exercising

37
Q

Glucagon increases [glucose]p by…

A

Increasing glycogenolysis/inhibiting glycogen synthesis

HARMONE OF HUNGRY STATE

38
Q

Cortisol increases [glucose]p by…

A

Stimulating protein catabolism, lypolysis and gluconeogenesis

39
Q

Which receptors control mean arterial BP? Where are the receptors, control centre + effectors located?

A

Baroreceptors, located in aortic arch + carotid sinus Control centre: CN IX + X to medulla oblongata
Effectors: heart + blood vessels

40
Q

Normal range for MAP?

A

Average arterial BP during single cardiac cycle

70-105 mmHg

41
Q

Formulae for calculating MAP?

A 
MAP = [(2x diastolic) + systolic]/3 MAP = diastolic + [systolic - diastolic]/3 
MAP = CO x TPR
42
Q

MAP of at least __ mmHg is needed to perfuse coronary arteries, brain and kidneys

A

60 mmHg

43
Q

Firing rate in baroreceptors ____ when MAP increases

A

Increases (sensitive to stretch: when you stretch them, firing increases)

44
Q

What is meant by BP, systolic and diastolic?

A

Outwards hydrostatic pressure exerted by blood on BV walls

  • when heart contracts
  • when heart relaxes
45
Q

Normal arterial BP

A

<140 systolic, <90 diastolic

46
Q

Cardiac output (CO) is…

A

The volume of blood pumped out by each ventricle per minute (SV x HR)

47
Q

Stroke Volume (SV) is…

A

Volume of blood pumped out by each ventricle per heart beat

48
Q

Increasing contractile strength of the heart causes stroke volume to ____

A

Increase

49
Q

What is meant by ‘autorhythmicity’?

A

Heart can beat rhythmically in abscence of external stimuli

50
Q

Influence of sympathetic and parasympathetic systems on HR and force of contraction…

A

Increase - NR on B1 receptors, Increase

Decrease - Ach on M receptors, No effect

51
Q

Main resistance vessels are…

A

Arterioles

52
Q

What is ‘total peripheral resistance’ and what is it controlled by?

A

Sum of all resistance of all peripheral vasculature in systemic circulation
Vascular SM especially arterioles - vasoconstriction (increase), vasodilatation (decrease)

53
Q

Vasomotor tone is described as…

Caused by?

A

Vascular smooth muscle being constricted at rest

Tonic discharge of sympathetic nerves

54
Q

Core body temperature is about…

A

37.8’C

55
Q

Basal metabolic rate is defined as…

A

The minimum amount of energy required to sustain body functions

56
Q

Which receptors monitor body heat? Where are they, the control centre and effectors located?

A

Thermoreceptors, located in the hypothalamus (CORE TEMP) and skin (PERIPHERAL TEMP)
Control centre: hypothalamus
Effectors: skeletal muscles, skin arterioles, sweat glands

57
Q

Mechanisms of heat gain…

A

Radiation
Convection
Conduction

58
Q

Mechanisms of heat loss…

A

Radiation
Convection
Conduction
Evaporation

59
Q

What contributes to half of total heat loss in the body?

A

Radiation - emission of energy as electromagnetic waves from a surface

60
Q

What term is used to describe ‘transfer of heat between objects in contact’?

A

Conduction

61
Q

What is convection?

A

Transfer of heat energy by air/water currents that carry heat away from the body

62
Q

What term is used to describe ‘the energy required to convert water in skin/ respiratory tract into vapour’

A

Evaporation

63
Q

What is the body’s temperature control centre? What parts are activated by the cold and warmth?

A

Hypothalamus
Cold = Posterior
Warmth = Anterior

64
Q

Fever is temperature between…

A

38-40’C

65
Q

Hyperthermia is temperature…

A

> 40’C

66
Q

Hypothermia is temperature below…

A

35’C

Y1 PRINCIPLES (10 decks)

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