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FBS1 > Principles of Physiology and Pharmacology > Flashcards

Principles of Physiology and Pharmacology Flashcards

1
Q

Which is the myelinating cell-type in the PNS?

A

Schwann cell

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2
Q

What does excitation-contraction coupling start with?

A

Propagation of APs along sarcolemma

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3
Q

Concerning body fluids and osmolality, select the incorrect statement

a) Plasma osmolality is 290mosmol/kg H2O
b) Isotonic saline has 150mmol/L of NaCl
c) 500ml of water containing 20mmol of CaCl2 has an osmolarity of 80mosmol/kg H2O
d) Normal blood has a haematocrit of 0.47 in adult males

A

500ml of water containing 20mmol of CaCl2 has an osmolarity of 80mosmol/kg H2O

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4
Q

Renal clearance values…

a) For insulin are a measure of GFR
b) Greater than the GFR indicates tubular secretion
c) Less than GFR are always indicative of tubular reabsorption
d) Can be measured non-invasively

A

Greater than the GFR indicates tubular secretion

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5
Q

How long is a cardiac action potential?

A

200 to 400 milliseconds

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6
Q

What type of Ca channels are found at the T-tubule membrane?

A

L-type/Dihydropyridine (DHP) receptors

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7
Q

What cells does omeprazole act on?

A

Parietal cells

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8
Q

Where are components of Herring bodies synthesised?

A

Preoptic and paraventricular nuclei of hypothalamus

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9
Q

What is the terminal cisternae?

A

The area where the sarcoplasmic reticulum on the myofibrils meet

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10
Q

What is nebulin?

A

Actin-binding protein that extends from Z band along length of actin filament
Acts as template to regulate actin length

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11
Q

What is titin?

A

Protein than extends Z-line to M-line

Anchors myosin to maintain central position in sarcomere

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12
Q

What are the 3 functional stages of the sarcomere?

A

Resting Stage
Contracting Stage
Stretched Stage

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13
Q

What type of contraction is present in the contracting stage of the sarcomere?

A

Concentric contraction

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14
Q

What type of contraction is present in the stretched stage of the sarcomere?

A

Eccentric contraction

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15
Q

What complex on tropomyosin blocks the head of actin?

A

Troponin

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16
Q

What does Calcium bind to when released into the sarcoplasm?

A

Troponin complex (Troponin C)

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17
Q

How many stages are there to muscle contraction and what they called?

A 
5 stages
Attachment
Release
Bending
Force Generation
Reattachment
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18
Q

How does muscle relax?

A

Calcium AT into sarcoplasmic reticulum to remove from cytosol
Stops binding to troponin

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19
Q

What are the 3 types of muscle fibres?

A

Slow twitch - oxidative type 1
Fast twitch - oxidative, glycolytic type 2A
Fast twitch - glycolytic type 2B

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20
Q

What is the length-tension relationship in a muscle?

A

Tension a muscle can generate related no of cross bridges formed between thick and thin filaments

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21
Q

What percentage of our body weight is water and what is it made up of?

A 
60% water (42L)
40% of water - intracellular space (28L)
(3.5L of which is blood cells)
15% is interstitial space  (10.5L)
5% is plasma space (3.5L)
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22
Q

What is the water content of lean tissue?

A

0.7L/kg

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23
Q

How to calculate interstitial space?

A

Interstitial space = ECS - plasma volume

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24
Q

How to calculate intracellular space?

A

Intracellular space = TBW - ECS

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25
Q

How would you measure plasma volume?

What does the substance have to be like?

A

Something that can’t cross capillaries

Evans Blue, labelled Inulin, Albumin

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26
Q

How would you measure extracellular space?

What does the substance have to be like?

A

Something that doesn’t enter cell easily

Na-24, Sucrose

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27
Q

How would you measure total body weight?

What does the substance have to be like?

A

Something that distributes with all water

H2O-8

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28
Q

What is the difference between osmolarity and osmolality?

A

Osmolarity - 1 osmole p/litre

Osmolality - 1 osmole p/kg

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29
Q

What causes crystalloid osmotic pressure?

A

Due to small diffusable ions (e.g. Na, Cl, K in body fluid)

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30
Q

What causes oncotic osmotic pressure?

A

Proteins that can’t cross cell membranes and displace water molecules

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31
Q

What is the main ion in plasma and what does it control?

A

Sodium, Blood volume

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32
Q

What is the main ion in intracellular fluid and what does it control?

A

Potassium, Cell volume

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33
Q

What are the 3 plasma proteins and what do they do?

A

Albumin - oncotic osmotic pressure, buffering of pH,
Alpha, beta, gamma globulins - haemostasis, transport, immune system
Fibringon - haemostasis

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34
Q

What is the lifespan of RBC?

A

120 days

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35
Q

What percentage of leucocytes is lymphocytes and what do they do?

A

20-40%

Produce immunoglobins

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36
Q

What percentage of leucocytes is monocytes and what do they do?

A

2-8%

Form macrophages

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37
Q

What makes up granulocytes in leucocytes and what does each do?

A

Neutrophils - 50-70%, phagocytosis, chemotactic
Eosinophils - 1-4%, phagocytosis, allergy
Basophils - ~0.5%, release His + heparin

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38
Q

What are platelets?

A

Fragments of megakaryocytes

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39
Q

What are the 3 types of negative feedback?

A

Neuronal
Endocrinal
Local

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40
Q

What is normalization?

A

Change in variable being regulated is compared against a set-point
Causes a response that tends to move variables back to the set point

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41
Q

What is amplification?

A

Change in variable triggers a response that causes further change in that variable

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42
Q

Where are the neuronal integrating centres for physiological control located?

A

Midbrain and Brain-stem

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43
Q

What are the endocrine organs (8)?

A 
Hypothalamus
Pituitary
Thyroid
Parathyroid
Adrenal cortex + medulla
Pancreas
Testes
Ovaries
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44
Q

What are the releasing hormones of the hypothalamus?

A

GHRH - Growth Hormone Releasing Hormone
CRH - Corticotrophin Releasing Hormone
TRH - Thyrotrophin Releasing Hormone
GnRH - Gonadotrophin Releasing Hormone

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45
Q

What are the inhibiting hormones of the hypothalamus?

A

Somastostatin

Dopamine

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46
Q

What hormones are secreted by the posterior pituitary?

A

Neuroendocrine
Oxytocin
ADH - anti-diuretic hormone

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47
Q

What hormones are secreted by the anterior pituitary?

A 
Endocrine
GH - Growth hormone
Prolactin
FSH - Follicle Stimulating Hormone
LH - Luteinizing Hormone
TSH - Thyroid Stimulating Hormone
ACTH - Adrenocorticotrophic Hormone
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48
Q

What are the types of hormones?

A 
Peptides
Polypeptides
Glycopeptides
AA derivatives
Steroids
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49
Q

What hormones have tyrosine as a derivative?

A 
Thyroxine T4 (in the thyroid)
Adrenaline (adrenal medulla)
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50
Q

What hormones do the ovaries secrete?

A

Progesterone

Estrogens

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51
Q

What type of hormones do the testes secrete?

A

Androgens e.g testosterone

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52
Q

What hormones does the adrenal cortex secrete?

A

Glucocorticoids e.g. Cortisol

Mineralocortocoids e.g. Aldosterone

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53
Q

What hormones have their receptor location in the plasma membrane and mechanism of action?

A

Peptides, Proteins, Glycoproteins, Catecholamines

Secondary messengers to change enzyme activity

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54
Q

What hormones have their receptor location in the intracellular (cyto/nucleus) and mechanism of action?

A

Steroids, thyroid hormones

Alter gene transcription

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55
Q

What is a natural example of positive feedback?

A

Parturition - contraction of uterus to expel fetus

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56
Q

What are the 2 types of circulation?

A

Pulmonary circulation - in series with systemic

Systemic circulation - mostly parallel with each other

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57
Q

How to calculate cardiac output?

A

Cardiac Output = Stroke Volume x Heart Rate

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58
Q

What is laminar flow?

A

Viscous drag at sides of tube slows fluid

Fastest in centre

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59
Q

What is the Fahraeus-Lindquist effect?

A

Cells tend to become aligned in fast-moving fluid

Axial streaming

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60
Q

What is turbulence?

A

Partial narrowing of artery

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61
Q

What can turbulence trigger?

A

Can trigger production of reactive oxygen species

Induce proliferation and migration of vascular sm cells

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62
Q

In the left ventricle, what does the pressure oscillate between?

A

0-120 mmHg

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63
Q

In the right ventricle, what does the pressure oscillate between?

A

0-20 mmHg

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64
Q

How are electrical events in cells measured?

A

Intracellular - Electrode inside cell
Extracellular - Electrode outside cell
Patch Clamping - Electrode sealed to cell surface

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65
Q

What types of medical diagnostic tools use extracellular recordings?

A

ECG - Electrocardiogram
EMG - Electromyograph
EEG - Electroencephalogram

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66
Q

When a membrane is at rest, what ion is it more permeable to?

A

Potassium

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67
Q

What is the difference between permeability and conductance?

A

Permeability - ease with which an ion can enter a membrane, (no of open channels)
Conductance - measure of current that gets across cell membrane

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68
Q

How many subunits does a potassium channel have?

A

4

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69
Q

A transmembrane current can either be…?

A

Resistive - ion flows through channels

Capacitative - ion approaches 1 surface of membrane and another is expelled from other side

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70
Q

What is a consequence of demyelination?

A

Current dissipates over a distance

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71
Q

What are heart cells connected by?

A

Intercalated discs

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72
Q

What are MEPPs?

A

Sub Threshold Minature Endplate Potentials

small depolarisations of post-synaptic terminals caused by release of single vesicle into synaptic cleft

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73
Q

What response can MEPPs cause?

A

EPSP - Excitatory Post-Synaptic Potential

IPSP - Inhibitatory Post-Synaptic Potential

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74
Q

Between skeletal and cardiac muscle, which one is triad and which one is dyad?

A

Skeletal - Triad

Cardiac - Dyad

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75
Q

Why is a cardiac action potential longer than a skeletal?

A 
Prevents tetany (involuntary contraction of muscle)
Protects against re-entrant arrhythmias
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76
Q

What type of receptor is present on Ca release channels?

A

Ryanodine receptors

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77
Q

How is Ca removed from the sarcoplasm?

A 
Via SERCA (sarco/endoplasmic Ca ATP-ase)
Via sarcolemmal Na/Ca exchanger
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78
Q

What is the force-frequency effect (in heart)?

A 
Increasing rate of cardiac contraction results in an increased tension development 
Gives treppe (staircase) effect on slow chart recorder
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79
Q

Do smooth muscle cells have striations?

A

No

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80
Q

What type of receptor does noradrenaline bind to and what does it activate?

A

Alpha 1 receptor

G-protein - activates phospholipase C - breakdown PIP2 (phosphatidyl inositol 4,5 biphosphate)

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81
Q

What receptor does adrenaline bind to?

A

Beta 1/2

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82
Q

What is unitary smooth muscle?

A

Not all cells have synaptic input

Excitation spreads through tissue by gap junctions

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83
Q

What is multi-unit smooth muscle?

A

Each smooth muscle cell has a synaptic input

Allows finer control of muscle

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84
Q

What g-protein is alpha-1 adrenergic receptor associated with and what does it stimulate?

A

Gq

IP3/Ca + DAG secondary messenger pathways to raise cellular [Ca]

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85
Q

What g-protein is alpha-2 adrenergic receptor associated with and what does it stimulate?

A

Gi

Inhibits adenylate cyclase to decrease cellular cAMP

86
Q

What g-protein are beta adrenergic receptors associated with?

A

Gs

87
Q

Where are each of the beta adrenergic receptors mainly located?

A

beta-1 - cardiac
beta-2 - vascular + airways
beta-3 - adipose, bladder

88
Q

What non-adrenergic, non-cholinergic neurotransmitters can be released that promote vasoconstriction?
(Along with what NT?)

A

Neuropeptide Y
ATP

NA

89
Q

What non-adrenergic, non-cholinergic neurotransmitters can be released that promote vasodilation?
(Along with what NT?)

A

Nitric oxide
Vasoactive intestinal polypeptide

AcH

90
Q

Under normal circumstances, what branch of the nervous system is heart rate under the control of?

A

Peripheral Nervous System

91
Q

What is the NTS in the brain stem?

A

Nucleus Tractus Solitarus

92
Q

What does the Botulinum toxin A do and what is it used to treat?
(How treat?)

A

Binds to and degrades SNAP-25, preventing exocytosis of AcH and other N.T
Treat an overactive bladder - prevent stimulation of muscarinic receptor on detrusor muscle

93
Q

Where should a drug be targeted for:

a) widespread effect
b) specific target

A

a) Sympathetic nerves in CNS/Sympathetic ganglion

b) Neuroeffector junction

94
Q

What drug can be used to inhibit noradrenaline synthesis?

A

Alpha methyl tyrosine

95
Q

What drug can inhibit noradrenaline storage and what does it do?

A

Reserpine

Block VMAT

96
Q

How is noradrenaline normally uptaken into vesicles?

A

Via Vesicular Monoamine Transporter (VMAT)

97
Q

What is noradrenaline metabolised by if not reuptaken?

Other hormones with this enzyme as well

A 
Monoamine Oxidase (MAO)
Dopamine, Serotonin
98
Q

What drug(s) can inhibit noradrenaline release and how?

A

Clonidine

Alpha-2 adrenergic receptor specific agonist and activation of these receptors inhibits N.T. release

99
Q 
What drug(s) can promote noradrenaline release?
(Secondary effect of one?)
A

Amphetamine - also inhibits MAO, increase free NA
Tyramine
Ephedrine

100
Q

What selective blocker(s) block alpha 1 adrenergic channels?

A

Doxazosin

Tamsulosin

101
Q

What is an example(s) of a non-selective beta blocker?

A

Labetolol

Propanolol

102
Q

What is an example(s) of a beta-1 selective blocker?

A

Atenolol

103
Q

What are some adverse effects of beta blockers?

A 
Fatigue
Reduced Peripheral Blood Flow
Bronchoconstriction
Increased risk of Cardiac Failure
Risk of hypoglycemia
104
Q

What receptor does Salbutomol effect?

A

Selective agonist of beta-2 receptor

105
Q

What 2 enzymes are endogenous and exogenous catecholamines broken down by?

A

MAO - Monoamine Oxidase

COMT - Catechol-O-Methyl Transferase

106
Q

What drugs inhibit MAO?

A

Phenylzine
Moclobemide
Selegiline

107
Q

What is the top, middle and bottom bit of the stomach called?

A

Fundus
Corpus
Antrum

108
Q

What chemical messengers are parietal cells acid secretion regulated?

A

AcH
Histamine
Gastrin

109
Q

What enzymes do the pancreas, SI, and salivary glands secrete to digest carbs?

A

Pancreas - alpha amylase
Salivary glands - alpha amylase
SI - 1,6-glucosidase

110
Q

What enzymes does the stomach, pancreas and SI secrete to digest proteins?

A

Stomach - pepsins, HCl
Pancreas - Carboxypeptidases
SI - Amino-peptidases, dipeptidases

111
Q

What hormone causes contraction of gall bladder and where is it secreted from?
(What else does the hormone cause?)

A

Cholecystokinin
Secreted by cells in duodenum
Relaxation of sphincter of Oddi

112
Q

What is bilirubin?

A

Yellow compound that occurs in normal catabolic pathway

From breakdown of heme

113
Q

What are enterocytes?

A

Intestinal absorptive cells

Columnar epithelial, line inner surface of SI and LI

114
Q

What are chylomicrons?

A

Re-esterified LCFA, monoglyc, lysophospholipids, cholesterol (absorbed by enterocytes)
Have specific apoproteins

115
Q

Where are apoproteins made in enterocytes and where do they go?

A

In RER

Moves to SER + associates with newly synthesised trigylcerides

116
Q

What is the receptor for AcH in the heart?

A

Muscarinic AcH receptor (mAcHR)

117
Q

What nerve supplies the parasympathetic innervation for the heart?

A

Vagus nerve carries parasymp preganglionic axons

118
Q

What is the receptor for noradrenaline in the heart?

A

Beta-1 adrenoreceptor

119
Q

How is noradrenaline synthesised from tyrosine and what are the enzymes involved?

A

Tyrosine ==> DOPA (Tyrosine hydroxylase)
DOPA ==> Dopamine (DOPA Carboxylase)
Dopamine ==> Noradrenaline (Dopamine beta-hydroxylase)

120
Q

What is the drug imipramine and what does it do?

A

Tricyclic antidepressant

Increases amount of noradrenaline in synapses by inhibiting uptake

121
Q

How is AcH formed and what is the enzyme?

A

AcCoA + Choline ==> AcH (choline acetyl)

Choline acetyl transferase

122
Q

Is AcH excitatory or inhibitory at:

a) Heart cells
b) Skeletal muscle

A

a) Inhibitory

b) Excitatory

123
Q

What is the receptor in the skeletal muscle for AcH?

A

Nicotinic AcH Receptor (nAcHR)

124
Q

What is myasthenia gravis?

A

When body produces antibodies against nAcH receptors

125
Q

What receptor is on blood vessels in the gut for noradrenaline?

A

Alpha-1 adrenergic

126
Q

What receptor is on blood vessels in skeletal muscle for noradrenaline?

A

Beta-2 adrenergic

127
Q

What receptor is on sweat glands for AcH?

A

Muscarinic AcH receptor

128
Q

What is pilocarpine?

A

Muscarinic AcH receptor agonist

129
Q

What nerve is associated with parasympathetic stimulation of the salivary glands?

A

Chorda lingual nerve

130
Q

What is the max rate of salivary flow in humans?

A

1ml/min.g

131
Q

What is intrinsic factor?

A

Glycoprotein combines with vitamin B12

Aiding absorption in ileum

132
Q

What is the section of the stomach just before the duodenum?

A

Pylorus

133
Q

What are the 3 stages of stomach digestion?

A

Propulsion
Grinding
Retropulsion

134
Q

What cell(s) in the stomach secrete HCl?

A

Parietal (oxyntic) cells

135
Q

What cell(s) in the stomach secrete mucus?

A

Superficial epithelial cells

Mucous neck cells

136
Q

What cell(s) in the stomach secrete pepsin and other digestive enzymes?

A

Chief cells

Endocrine cells

137
Q

What are fenestrated capillaries?

A

Capillaries that have pores that allow larger molecules through

138
Q

What is the constant concentration parietal cells secrete H+?

A

150mEq/L

139
Q

What is an ECL cell?

A

Enterochromaffin-like cell

Neuroendocrine found in gastric glands of gastric mucosa beneath epithelium

140
Q

What endocrine hormone(s) does the D cell secrete and what does it do?

A

Somatostatin

Binds to g cell in stomach epithelium, limits further gastrin secretion

141
Q

What does the drug omeprazole do?

A

Selectively and irreversibly inhibits H+, K+, ATP-ase by forming a disulphide link
Prevent acid secretion

142
Q

What cells help regulate the rhythmic cycles of activity of the visceral smooth muscle?

A

Pacemaker cells (interstitial cells of Cajal)

143
Q

How many litres of food are ingested before the stomach pressure stops being constant?

A

1L

144
Q

What is the frequency of peristaltic waves in the stomach when food is being digested?

A

3 per minute

145
Q

How much chyme is usually delivered to the duodenum?

A

3ml

146
Q

What are the hormones involved in the regulation of gastric activity?

A

Secretin
Cholecystokinin (CCK)
Gastric Inhibitory Peptide (GIP)
Motilin

147
Q

What are the 2 interconnected plexuses in the enteric nervous system?

A

Myenteric

Submucosal

148
Q

What transporter transports fructose?

A

GLUT5

149
Q

What are oligopeptides?

A

Peptide molecule that have small no of AA residues

150
Q

How are oligopeptides absorbed into the intestine?

A

H+/Oligopeptide cotransporter PepT1

Into enterocyte across apical membrane

151
Q

What are the 2 membranes in an enterocyte?

A

Apical membrane

Basolateral membrane

152
Q

What is Hartnup disease?

A

Autosomal-recessive disorder
L-phenylalanine cannot be uptaken
Can absorb if in form dipeptide L-phenylalanyl-L-leucine

153
Q

What is cystinuria?

A

Autosomal recessive disorder
L-arginine cannot be uptaken
Can absorb if in form dipeptide L-arginyl-L-Leucine

154
Q

How is vitamin A absorbed from intestine?

A

Absorbed and transported in newly synthesised chylomicrons

Taken up by liver for further hydrolysis of retinyl esters

155
Q

How is vitamin E absorbed?

A

Absorbed primarily in form of alpha and gamma tocopherol

Incorporated into chylomicrons + VLDL

156
Q

What enzymes hydrolyse dietary retinyl esters in the lumen?

A

Pancreatic triglyceride lipase (PTL)
Pancreatic Lipase-related Protein 2 (PLRP2)
Intestinal brush border enzyme - phospholipase B (PLB)

157
Q

What happens to unesterified retinol(ROH)?

A

Passively diffuses into enterocytes
Complexed with cellular retinol binding protein type 2 (CRBP2)
Re-esterified by retinol acyltransferase

158
Q

What is the active form of vitamin D called?

A

Calcitriol

159
Q

What are the 2 types of nephrons?

A

Cortical (85%) - outer 2/3 of cortex, short loops of Henle

Juxtamedullary (15%) - inner 1/3 of cortex, long loops of Henle

160
Q

What are the names of the capillaries around the loops of Henle?
(Name when not around loops of Henle?)

A

Vasa recta

Glomerular + peritubular

161
Q

What is glomerular filtration rate(GFR)?

A

Volume of fluid filtered from glomeruli p/min in ml/min

162
Q

What 3 factors does GFR rely on?

A

Starling forces
Surface area of filtration interface
Hydraulic permeability of capillaries

163
Q

What does PAH clearance equal?

A

Renal plasma flow

164
Q

Where is sodium reabsorbed in the loop of Henle?

A

Passive in thin ascending limb
Actively in thick ascending limb
Not in descending limb

165
Q

What are the 2 types of cells in the collecting ducts?

A

Principal cells

Intercalated cells

166
Q

What is urea?

A

Breakdown product of protein

167
Q

What is tonicity?

A

Concentration of only non-penetrating solutes

168
Q

What type of aquaporins are on the:

a) Luminal membrane
b) Basolateral membrane

A

a) AQP2

b) AQP3 + AQP4

169
Q

What does a low water intake do to plasma osmolality?

A

Increase it

170
Q

What is diuresis?

A

Increases/excessive production of urine

171
Q

What factors other than osmoreceptors can control ADH and what are their effects?

A

Inhibit - alcohol

Stimulate - nicotine, nausea, pain, stress

172
Q

What are the 2 main types of diabetes insipidus?

A

Neurogenic - congenital/head injury

Nephrogenic - inherited (mutated V2 receptor)/aquired

173
Q

What 3 elements maintain K balance?

A

Renal excretion
Gastrointestinal losses
Cellular shifts

174
Q

What is hypokalemia?

A

Plasma [K+] < 3.5mM

175
Q

What is hypokalemia caused by?

A

Increased external losses
Redistribution into cells
Inadequate K+ intake
Increased external losses in urine

176
Q

What is hyperkalemia?

A

Plasma [K+} > 5.5mM

177
Q

What is hyperkalemia caused by?

A

Decreased external losses

Redistribution out of cells

178
Q

What are the 5 actions of angiotensin II?

A 
Stimulates proximal tubule Na+ reabsorption
Stimulates ADH release
Causes aldosterone secretion
Causes thirst
Vasoconstricts small arterioles
179
Q

What is the AT1 receptor, where is it located and what does it cause?

A

Angiotensin II Type 1 receptor
Present on luminal + basolateral membrane
Stimulates Na+ reabsorption

180
Q

What peptides are released when the heart stretches due to high blood volume/pressure?

A

Natriuretic peptides (NP)

181
Q

What are the 2 types of NP?

A

ANP - secreted from atrial myocardium

BNP - secreted from ventricular myocardium

182
Q

Where does bicarbonate (HCO3-) reabsorption occur?

A

Proximal tubule
Ascending LoH
Cortical collecting duct - intercalated cells type A

183
Q

What is the cause of respiratory acidosis?

A

Caused of insufficient CO2 excretion by lungs

184
Q

What are the 2 types of respiratory acidosis?

A

Acute - abrupt failure in ventilation

Chronic - 2ndary to many diseases e.g. airway obstruction, lung damage

185
Q

What are the 3 main responses in the body to regulate acid-base status?

A

Chemical buffers
Brainstem respiratory centre
Renal mechanisms

186
Q

What is metabolic acidosis characterised by?

A

A fall in plasma bicarbonate conc

187
Q

What is the cause of respiratory alkalosis?

A

Excessive central respiratory drive

188
Q

Does colon epithelium have villi?

A

No, it’s flat with deep crypts

189
Q

What are the 2 types of water absorption?

A

Paracellular - via tight junctions between cells

Transcellular - across cell membranes via aquaporins

190
Q

What is action of the cholera toxin?

A

Permanently activates adenylyl cyclase
Elevating cAMP in crypt cells
Enhancing secretion

191
Q

What is the most prevalent bacteria in gut flora?

A

Gram negative bacteria

Bifido bacteria

192
Q

What type of bacteria can breakdown fibre?

A

Colonic bacteria

193
Q

Calculation for mean arterial blood pressure (MABP)?

A

MABP = CO x TPR

cardiac output x total peripheral resistance

194
Q

What 2 things does increasing the length of the sarcomere cause?

A

Increased cross-bridge overlap

Increased Ca sensitivity of myofilaments (troponin C)

195
Q

Briefly describe vascular smooth muscle contraction with noradrenaline

A

Noradrenaline binds to alpha 1 receptor
Activates g protein, activates phospholipase C which breaks down PIP2 ==> IP3 + DAG
IP3 - open channel on SR, release Ca2+
DAG - Open RGC, increase Ca2+ + membrane depolarisation by opening VGCC
Goes to neighbouring cells via gap junctions

G protein also activates rho kinase which increases Ca2+ sensitization

196
Q

Briefly describe NO-mediated vasodilation

A

NO activates guanylate cyclase, converts GTP ==> cGMP which activates protein kinase G
Opens K+ channels on membrane + membrane hyperpolarized (also VGCC closed so x Ca2+ enter)
SERCA + PMCA ATPases activated so Ca2+ decrease

cGMP broken down ==> GMP by phosphodiesterase (PDE)

197
Q

Briefly describe cAMP mediated vasodilation

A

Binding of adrenaline/adenosine/prostacyclin to beta 1/2 receptors
Activates adenylate cyclase which ATP ==> cAMP
Activates protein kinase A, same effects as protein kinase G

cAMP broken down ==> AMP by PDE

198
Q

What are spontaneous oscillations in smooth muscle called?

A

Slow wave (most visceral sm)

199
Q

What are autacoids?

A

Physiologically active factor released by cells typically acts locally + briefly on other cells

200
Q

How many subunits in a nicotinic receptor and what receptors are found in muscle + ganglionic?

A 
5 subunits
Muscle receptor (N1) - 2 x alpha 1 type, beta 1, gamma, epsilon
Ganglionic receptor (N2) - 2 x alpha 3 type, 3 x beta 4 type
201
Q

What is the difference between antagonist and agonist?

A

Antagonist blocks receptor + blocks response

Agonist binds to receptor + stimulates response

202
Q

What causes gallstones?

A

Too much H2O absorption from bile
Too much bile acid absorption from bile
Too much cholesterol in bile
Inflammation of epithelium

203
Q

Outline cobalamin handling by stomach + proximal SI

A

Cobalamin bound to proteins in food - acid pH + pepsin release it from dietary protein
Gastric glands secrete haptocorrin, bind to CBL
Gastric parietal cells secrete IF
Pancreas secretes HCO3- + proteases
CBL released after proteolytic degradation of haptocorrin
IF-CBL complex forms which ileal enterocyte absorbs

204
Q

How do glomerular mesangial cells alter their S.A for filtration?

A

Contain sm filaments that can contract cell

205
Q

What Na transporters are present on the luminal membrane of the proximal tubule?

A

Na+-H+ exchanger (NHE3) (Na+ into cell)

Na+-Glc/AA symporter

206
Q

What Na transporters are present on the luminal membrane of the thick ascending limb?

A

Na+-K+-2Cl- cotransporter
(N+, K+ into cell)
K+ channel (K+ into filtrate)

207
Q

What Na transporters are present on the basolateral membrane of the thick ascending limb?

A

Na+-K+ ATPase pump

208
Q

What Na transporters are present on the basolateral membrane of the distal tubule?

A

Na+-K+ ATPase pump

209
Q

What Na transporters are present on the luminal membrane of the distal tubule?

A

Na+-Cl- cotransporter

210
Q

What Na transporters are present on the luminal membrane of the principal cells of collecting duct?

A

Na+ channel

211
Q

What Na transporters are present on the basolateral membrane of the principal cells of collecting duct?

A

Na+-K+ ATPase pump

212
Q

What do these values of Ch2o reflect?

a) >0
b) = 0
c) <0

A

a) Hypo-osmotic (dilute) urine
b) Iso-osmotic urine
c) Hyper-osmotic (concentrated) urine

FBS1 (5 decks)

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