Physiology Flashcards

1
Q

What do membranes do?

A

Control exit and entry of waste products, they are selectively permeable.
-Maintain ion concentration gradients and participate in the joining of cells

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2
Q

What is the plasma membrane?

A
  • Phospholipid bilayer
  • Cholesterol
  • Proteins
  • Carbohydrates
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3
Q

What does cholesterol add to plasma membrane?

A

Fluidity and stability

-Stiffens the membrane

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4
Q

3 types of proteins in plasma membrane?

A

Integral
Transmembrane
Peripheral

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5
Q

Where are integral proteins in membrane?

A

Embedded in bilayer

-Receptors

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6
Q

What are names of transmembrane proteins and where are they?

A

Transporters/channels

-Extend through membrane

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7
Q

What is different about peripheral proteins compared to transmembrane and integral?

A

They do not penetrate the membrane

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8
Q

What makes up the glycocalyx?

A

Glycoproteins

Glycolipids

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9
Q

Functions of lipid bilayer?

A

Basic structure of membrane
Hydrophobic interior serves as a barrier
Responsible for fluidity

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10
Q

Function of carrier/transport proteins?

A

Span the membrane and are substrate specific

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11
Q

Where are docking marker acceptors?

A

Inner membrane surface

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12
Q

How do docking membrane acceptors work?

A

Interact with secretory vesicles leading to exocytosis of vesicle contents

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13
Q

How do receptor proteins work?

A

Bind specific molecules - lock & key

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14
Q

Types of cell adhesion molecules (proteins)?

A

Cadherins

Integrins

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15
Q

What do cadherins do? And what are they?

A

Hold cells within tissues together

Cell adhesion molecules

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16
Q

What do integrins do?

A

Span membrane acting as a link between extra and intra-cellular environments

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17
Q

2 Functions of carbohydrates?

A
  • Serve as self identity markers enabling cells to identify and interact with one another (different cell types have different markers)
  • Role in tissue growth
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18
Q

3 types of specialized cell junctions?

A

Gap junctions
Tight Junctions
Desmosomes

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19
Q

Desmosomes?

A

Adhering junctions that anchor cells together

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20
Q

Tight junctions?

A

Join lateral edges of epithelial cells near luminal/apical membrane

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21
Q

Gap junctions?

A

Communicating junctions that allow movement of charge carrying ions and small molecules between 2 adjacent cells

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22
Q

What does Fick’s law of diffusion relate to?

A
  • Magnitude of conc gradient
  • SA of the membrane diffusion is taking place across
  • Lipid solubility of substance
  • Molecular weight of substance
  • Distance which diffusion must take place across
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23
Q

What is an electrochemical gradient?

A

Where an electrical and a concentration (chemical) gradient may be acting on a particular ion at the same time

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24
Q

Osmosis?

A

Net diffusion of water down a concentration gradient

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25
Q

What are water channels called?

A

Aquaporins

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26
Q

Osmolarity?

A

Concentration of osmotically active particles in a solution

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27
Q

What is osmolarity measured in?

A

Osmoles/Litre

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28
Q

Osmolarity of body fluids?

A

~300mOsm

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29
Q

Tonicity?

A

Effect a solution has on cell volume

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30
Q

Units of tonicity?

A

NO UNITS

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31
Q

What is carrier-mediated transport?

A

Substance binds to specific carrier and undergoes transformational change to transport substance

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32
Q

What is saturation another term for?

A

Transport maximum (Tm)

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33
Q

Fact file of facilitated diffusion?

  • Energy?
  • Mediated?
  • Gradient direction
A

No energy required

  • Carrier mediated
  • From high to low conc
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34
Q

Active transport fact file?
Energy?
Gradient?
Types?

A

-Energy required
-Low concentration to high concentration
-Primary= energy directly required
Secondary= Energy required but not used directly

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35
Q

Secondary active transport energy?

A
  • Energy required but not used directly

- It is stored in the form of an ion concentration gradient (usually Na+)

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36
Q

Mechanisms of secondary active transport?

A

2 mechanisms

  • Symport- contransport= solute and Na+ move in the same direction
  • Antiport - exchange/countertransport = Solute and Na+ move in opposite directions
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37
Q

What is K+/Na+ATPase used in? Where is it?

A

Primary active transport

Plasma membrane of all cells

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38
Q

Ratio of NA:K movement in primary AT?

A

3 Na out

2 K in

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39
Q

3 important roles of Na+/K+ATPase?

A
  • Establish Na/K concentration gradients across plasma membrane
  • Regulate cell volume by controlling concentration of solutes inside the cell
  • Energy used to drive the pump indirectly serves as energy source for secondary AT
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40
Q

Types of vesicular transport?

A

Endocytosis

Exocytosis

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41
Q

Endocytosis?

A

Membrane pinches off to engulf substance

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42
Q

Exocytosis?

A

Vesicle fuses with membrane, releasing contents to ECF

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43
Q

What is Em? Units?

A

Membrane potential - separation of opposite charges across membrane
-mV

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44
Q

Concentration gradient direction for K+?

A

Outward

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45
Q

Concentration gradient for Na+?

A

Inward

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46
Q

Electrical gradient for K+/Na+?

A

Both positively charged so the EG for both will be towards the negatively charged side of the membrane

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47
Q

Equilibrium potential for K+?

A

When concentration and electrical gradients balance eachother

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48
Q

Membrane potential at Ek?

A

-90mV

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49
Q

Membrane potential for Na+?

A

ENa+ +61mV

50
Q

Nernst equation?

A

Eion=

61Log10 [ion]0/[ion]i

51
Q

Resting membrane potential for a typical nerve cell?

A

-70mV

52
Q

What is the Nernst equation used for?

A

To find cell potential under non-standard conditions

53
Q

Why is Em of nerve cell close but not identical to Ek?

A

Slight inward leak of Na+ into the cell, K+ gradient is most important factor here

54
Q

Goldman-Hodgkin-Katz equation

A

Em= 61Log10 Pk+[K+]o + PNa+ [Na+]o
___________________________________
Pk+[K+]i + PNa+ [Na+]i

55
Q

What is the Goldman Hodgkin Katz equation used for?

A

Calculating overall membrane potential

56
Q

What does P stand for in Goldman Hodgkin Katz equation?

A

Relative permeability

57
Q

Hyperpolarization?

A

More negative

58
Q

Depolarisation?

A

More positive

59
Q

Which hormones control glucose in post absorptive and absorptive states?

A

Insulin

Glucagon (pancreas)

60
Q

Which hormone controls glucose in emergencies?

A

Adrenalin (adrenal gland)

61
Q

Which hormones control glucose during starvation?

A
Cortisol (Adrenal)
Growth hormone (pituitary)
62
Q

Types of pancreatic islets of langerhan?

A

Alpha
Beta
Delta

63
Q

What do alpha pancreatic islets of langerhan produce?

A

Glucagon

64
Q

What do beta pancreatic islets of langerhans produce?

A

Insulin

65
Q

What do delta pancreatic islets of langerhan produce?

A

Somatostatin

66
Q

What are pancreatic islets of langerhan located in?

A

Endocrine glands

67
Q
What happens to levels of
-Glucose 
-Insulin 
-Glucagon
in absorptive state?
A
  • Glucose rises
  • Insulin rises
  • Glucagon falls
68
Q

Which process does insulin favour?

A

Anabolism

69
Q

What is converted to what by insulin?

A

Glucose -> Glycogen
Fatty acids-> Triglycerides
Amino acids -> protein

70
Q

What is the hormone of the fed state?

A

Insulin

71
Q

Effects of insulin?

A
  • Lowers glucose by stimulating uptake from blood and activating liver enzymes
  • Promoting secretion= increased glucose= increased parasympathetic activity
  • Inhibiting secretion = decreased glucose = increased sympathetic activity
72
Q

Which process does glucagon favour?

A

Catabolism

73
Q

What is converted to what by glucagons presence?

A

Glycogen -> Glucose

Triglycerides-> Fatty acids

74
Q

What is glucagon the hormone of?

A

The hungry state

75
Q

Effects of glucagon?

A

Raises glucose by increasing glycogenesis, inhibiting liver glycogen synthesis, promoting liver gluconeogenisis, lipolysis

76
Q

What happens in type 1 diabetes?

A

Little/no insulin release
-Defect in beta cells
Insulin injections required
-Early onset

77
Q

Stimulation of release of glucagon?

A

Decreased blood glucose
Amino acids
Sympathetic nerve activity

78
Q

Stimulation of inhibition of release of glucagon?

A

Raised blood glucose

Insulin

79
Q

Type 2 diabetes?

A

Insulin secretion MAY be normal
-Defect in insulin sensitivity
-Diet/exercise/oral drugs
ADULT onset

80
Q

Adrenaline raises glucose. True or false?

A

True

  • Stimulates gluconeogenesis
  • Stimulates glycogenolysis
81
Q

When is adrenaline released?

A

During short term emergencies

82
Q

What does cortisol do to glucose levels?

A

Raises them

83
Q

What processes does cortisol stimulate?

A

-Protein catabolism
-Gluconeogenesis
-Lipolysis
-

84
Q

Where is growth hormone secreted from?

A

Anterior lobe of pituitary

85
Q

In response to ________, growth hormone does 3 things
1.
2.
3.?

A

Starvation

  1. Decreases glucose uptake by muscle
  2. Mobilises glucose form liver
  3. Promotes lipolysis in fat cells
86
Q

Where are baroreceptors located?

A

Aortic arch

Carotid sinus

87
Q

Process of baroreceptor activation?

A
  1. Sensitive to stretch

2. Firing rate increases when MAP increases (decreases when MAP decreases)

88
Q

What happens to baroreceptor firing if high blood pressure is sustained?

A

Firing decreases

They only respond to acute changes

89
Q

Definition of blood pressure?

A

The outwards (hydrostatic) pressure exerted by the blood on blood vessel walls

90
Q

Systolic pressure?

A

When the heart is contracting (normally <140mmHg)

91
Q

Diastolic pressure?

A

When the heart is relaxed (normally <90mmHg)

92
Q

MAP?

A

The average arterial blood pressure during a single cardiac cycle

93
Q

What is the average MAP range?

A

70-105mmHg

94
Q

MAP equations when you have diastolic and systolic?

A
MAP = [(2x diastolic) + systolic]/3 
MAP = DBP + 1/3 difference between SBP/DBP
95
Q

MAP equations?

A

MAP = Cardiac output (CO) x Total peripheral Resistance (TPR)

96
Q

CO equation?

A

CO = stroke volume (SV) x Heart rate (HR)

97
Q

How can MAP be regulated?

A

By regulating

  • HR
  • SV
  • TPR
98
Q

Which vessels control resistance?

A

Arterioles

99
Q

Tissue?

A

Group of cells with similar structure and specialized function

100
Q

Organs?

A

Two or more types of primary tissues which perform a particular function

101
Q

General idea of how homeostasis works?

A
  • Sense deviations from normal
  • Integrate this information
  • Make appropriate adjustments to restore controlled variable to a desired variable
102
Q

Intrinsic controls?

A

Local controls inherent in an organ

103
Q

Extrinsic controls?

A

Regulatory mechanisms initiated outside an organ

Accomplished by nervous and endocrine systems

104
Q

Feedforward?

A

Responses made in anticipation of change

105
Q

Feedback?

A

Responses made after a change has occurred

106
Q

What does positive feedback do?

A

Amplifies a change

107
Q

What temperature is the body homeostatically maintained at?

A

37.8 celcius

108
Q

What does having normothermia optimise?

A

Cellular metabolism

Cellular function

109
Q

What temperature range should your ear drum have?

A

35.5-37.5)

110
Q

What temperature range should rectal passage have?

A

(36.7- 37.5)

111
Q

Which hormones can increase metabolic heat?

A

Adrenaline, noradrenaline, thyroxine

112
Q

What is basal metabolic rate?

A

Basic level of heat production

113
Q

What is conduction dependent on and what is it?

A

Transfer of heat between objects

dependent upon temperature gradient and thermal conductivity

114
Q

Passive evaporation is called?

A

Sweating - controlled by sympathetic nervous system

115
Q

Maintaining core temperature negative feedback mechanism?

A
  • Sensor detects change in controlled variable
  • Sends signal to hypothalamus
  • Effectors (skin muscles, arterioles, sweat glands) triggered to respond and restore variable to normal
116
Q

What is the hypothalamus?

A

Small area in the brain

Body’s thermostat

117
Q

What happens in the posterior hypothalamic centre?

A

Controls cold

  • Vasoconstriction
  • Increased muscle tone
  • Shivering
118
Q

What controls warmth in the hypothalamus?

A

Anterior hypothalamic centre

  • Vasodilation
  • Sweating
  • Decreased muscle tone
119
Q

Mechanism of fever?

A
  • Macrophages release chemicals which act as endogenous pyrogen
  • Stimulates hypothalamus to release prostaglandins
  • Resets thermostat to higher temp
  • Hypothalamus initiated mechanism to heat body (cold response)
  • Thermostat reset to normal if pyrogen release is reduced/stopped
120
Q

What temperature is fever?

A

38-40 degrees celcius

121
Q

Hyperthermia?

A

> 40 degrees celcius

122
Q

Hypothermia?

A

<36 degrees or below