MRCS Physiology Flashcards

1
Q

5 reasons for right shift Hb on curve?

A

Increased CO2, increased temp, increased H+ conc (low pH), increased DPG, HbSS

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2
Q

6 reasons for left shift Hb O2 curve?

A

Low temp, low DPG, low CO2, low H+ (increased PH), met/CO Hb and fetal Hb

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3
Q

What shift does fetal Hb cause in o2 Hb curve?

A

Left

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4
Q

pH of venous blood normally?

A

5.33

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5
Q

What do kupffer cells of liver do?

A

Recycle old red blood cells

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6
Q

Vitamin D production site and 2 step hydroxylation process sites?

A

Produced in skin via sunlight (D3)
Then hydroxylated in liver to 25hydroxy vit D calcifediol
Then hydroxylated again in kidney to 1 25 HVD calcitriol

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7
Q

How does activated vit D work? 3 ways

A

Increases Ca and Po4 uptake gut
Increases renal reabsorption of Ca and Po4
Promotes osteoclast activity

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8
Q

Where is calcium absorbed in GI tract?

A

Duodenum

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9
Q

What do haptoglobins do? Why might they be low?

A

Eliminate free Hb from plasma

In hemolytic anaemia get saturated and absorbed by RES

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10
Q

What does platelet derived growth factor do? What disease process is it implicated in?

A

Stimulates intimal smooth muscle proliferation and synthesis of collagen and elastin
Development of atheroma

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11
Q

What secretes platelet derived growth factor? 2 things

A

Macrophages

Endothelium

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12
Q

What is the blood supply to atheromatos plaque called?

A

Vasa vasorum

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13
Q

Bph stands for?

A

Benign prostatic hyperplasia

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14
Q

What does thymus do?

A

Receives immature T cells and does positive and negative selection

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15
Q

4 phases of wound healing w time scales?

A

Haemostasis - minutes
Inflammation - day 1 to 5
Regeneration - day 5 - 56
Remodelling - 6 weeks to 1 year

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16
Q

When does granulation tissue appear in wound healing?

A

Regeneration phase - day 5 to 56

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17
Q

Stage 1 of haemorrhagic shock?

A

Less than 750 ml blood (15%)

Normal everything, normal or high pulse pressure

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18
Q

What is circulating volume in L approx?

A

5L

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19
Q

Stage 2 of haemorrhagic shock?

A

750-1500 mls 15-30%

Tachycardia, falling pulse pressure, mild high RR but normal BP

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20
Q

Stage 3 of haemorrhagic shock?

A

1500-2000mls 30-40%
Tachy over 120
Bp drops
Confused

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21
Q

Stage 4 of haemorrhagic shock?

A

Anuric less than 5 ml per hour
BP drops
Lethargic and drowsy

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22
Q

If BP drops which stage of haemorrhagic shock?

A

At least 3

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23
Q

If tachycardia with decrease pulse pressure which stage of haemorrhagic shock?

A

At least 2

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24
Q

What is type 2 hypersensitivity? Examples?

A

Cytotoxic- IgG/M against cell surface antigens e.g. ABO incompatibility/AIHA, Goodpastures

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25
Q

Type 3 hypersensitivity? Examples?

A

Immune complex IgGMA deposition, soluble antigens, e.g. SLE or aspergillus

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26
Q

Type 4 hypersensitivity? Examples?

A

T cell mediated delayed immune

E g. Granuloma formation, contact dermatitis, GVHD

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27
Q

Mnemonic for types 1 to 4 hypersensitivity?

A
A naphylactic
C ytotoxic
I mmune complex
D elayed immune
Has bad allergies
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28
Q

3 phases of secretion of gastric acid? Mediators?

A

Cephalic (smell/taste) - vagal mediated Hcl and gastrin release
Gastric (stretch) - gastrin release
Intestinal (duodenal food) - CCK and secretin

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29
Q

3 factors increasing gastric acid secretion?

A

Gastrin
Vagal nerve stimulation
Histamine

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30
Q

3 things reducing gastric acid secretion?

A

CCK
Secretin
Somatostatin

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31
Q

How does somatostatin reduce gastric acid release?

A

By inhibiting histamine

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32
Q

What secretes gastrin? What does it do?

A

G cells
Increases HCl pepsinogen and IF secretion
Increases gastric motility and emptying

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33
Q

What secretes CCK? What does it do? In response to?

A

I cells in upper duodenum in response to fat TGLs and protein
Delays gastric emptying increases pancreatic secretions and causes gallbladder contraction

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34
Q

What secretes secretin? What does it do?

A

S cells in duodenum

Increases pancreatic secretions in response to acid and chyme

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35
Q

What does VIP do and where is it secreted?

A

Small intestine and pancreas - increase pancreatic secretions in response to neural stimulation

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36
Q

What secretes somatostatin? What does it do?

A

D cells in pancreas and stomach

Stops everything basically, inhibits histamine and produces mucous

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37
Q

Which part of the immune system is complement involved in?

A

Innate immune system

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38
Q

Which part of the complement system is involved in response to pathogen surfaces?

A

MBL

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39
Q

What arr the 3 parts of complement system?

A

Classic - Ag/Ab complexes
Alternative - activating surfaces e.g. pathogen or injured tissue
MBL - direct response to pathogen surfaces

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40
Q

What is classical complement system activated by?

A

AgAb complexes

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41
Q

What is alternative complement system activated by?

A

Surfaces e.g. injured tissue or pathogen

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42
Q

Which part of complement system activates mast cells?

A

Anaphylotoxin - C5a

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43
Q

Which part of complement system primes opsonization for phagocytosis?

A

C3b

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44
Q

What is main complement mediator for inflammation and chemotaxis?

A

C3a

45
Q

What forms the MAC in complement and what pathway is this called?

A

C5b to c9

Lytic pathway

46
Q

MAC Deficiency can lead to which infections?

A

Neisseria and gram negatives

47
Q

What innervates long head of triceps and what does it do?

A

Radial nerve - stabilises shoulder in abduction

48
Q

What cord and roots form radial nerve?

A

Posteiror cord

C5 to t1

49
Q

What is the branch of the radial nerve in the arm innervating supinator, extensor carpi radialis longus and brevis and abductor policis longus?

A

Posterior interosseus

50
Q

What nerve innervates brachioradialis?

A

Radial

51
Q

7 things innervated by radial nerve?

A
Triceps 
Brachioradialis
Supinator
Extensor carpi radials
Extensor carpi longus and brevis 
Abductor policis longus
52
Q

What is the extrinsic pathway activated by? What does this do?

A

Tissue factor

Activates 7 to 7a

53
Q

Which test measures extrinsic pathway?

A

PT

54
Q

Which test measures intrinsic pathway?

A

APTT

55
Q

What activates intrinsic pathway? What does this do?

A

Exposed collagen via tissue injury
Does TENET
Twelve Eleven Nine Eight Ten activation

56
Q

What is the joint goal of intrisnic and extrinsic coag pathways?

A

Activating factor 10 for the common pathway

57
Q

What does factor Xa do? What helps it?

A

Actiavtes prothrombin to thrombin (2 to 2a)

Reauires factor 5 to 5a and calcium

58
Q

What does thrombin do in coag cascade?

A

Activates fibrinogen to fibrin (1 to 1a)

59
Q

What clotting factor cross links fibrin to form clot with platelets?

A

13a

60
Q

How do protein C and S work? What do they do? Relation between warfarin and protein C?

A

Modulate coag cascade - anticoagulants

Warfarin inhibits protein C to transients make clotting more likely

61
Q

Where are the cell cycle stop checkpoints? What are they?

A

G1, S/G2 and M
G1 - restriction point, go to G0 fails
S/G2 - Dna damage checkpoint
M - spindle checkpoint

62
Q

Outline PMAT?

A

P - spindle fibres form, membrane breaks down
PM - spindles attach to chromosomes
M - chromosomes align
A - centromes divide and sister chromatids migrate to opposite poles
T - nuclear membrane reforms, chromosomes decondense and fibres disappear

63
Q

Where is carotid body? What about carotid sinus?

A

Body is behind carotid bifurcation

Carotid sinus is at origin of ICA

64
Q

What type are carotid body receptors and what are the stimulated by primarily? To cause what?

A

Chemoreceptors stimulated primarily by low O2 to stimulate ventilation

65
Q

Hormonal control of lactation?

A

Prolactin causes development of breast, mammary gland proliferation, milk production following suckling
Oxytocin causes contraction and milk expulsion in response to suckling

66
Q

What does PTH do to phosphate?

A

Reduces reabsorption in PCT to lower level

67
Q

Where is most phosphate reabsorbed in kidney?

A

PCT

68
Q

Why does PO rise in AKI?

A

Less filtration

69
Q

How does calcitonin lower calcium?

A

Suppresses osteoclast activity to reduce bone breakdown

70
Q

With what percentage of stenosis is carotid endarterectomy indicated?

A

Over 70%

71
Q

Which antibody type is involved in alternative complement payhway?

A

IgA

72
Q

At which spinal level is ampulla of vater?

A

L2

73
Q

What do alpha receptors do?

A

Vasoconstriction peripherally

74
Q

What do beta receptors do?

A

Positive chronotropism and isotropic for heart

Also bronchodilation

75
Q

How does norad work?

A

Peripheral vasoconstriction via alpha agonism

76
Q

How does dobutamine work?

A

Beta 1 agonism - increases contractility and cardiac output

77
Q

Around what days does spinal cord extend rostrally and caudally in development?

A

D 24 and 26 respectively

78
Q

What is a Jefferson fracture?

A

Bilateral C1 fracture anteiror and posterior due to axial loading

79
Q

What is a hangman’s fractufe?

A

Bilateral pars fracture due to hyperextension

80
Q

Describe the low and high dose dexamethasone test?

A

Give low dose and check cortisol - should be suppressed

Give high dose and check cortisol - if suppressed by high but not low suggests primary cushings disease

81
Q

What suggests cushings disease in dex suppression test?

A

High dose suppresses but not low

82
Q

What if cortisol not suppressed by high or low dose dex? What to check then?

A

Suggests not Cushings disease - check ACTH. If high suggests ACTH oma e.g. ectopic lung, if low suggests primary hypercortisolism

83
Q

What is cushings disease?

A

ACTH secreting pituitary adenoma (secondary hypercortisolism)

84
Q

What does otic ganglion do? Associated nerve?

A

Parasymp to parotid

CN 9

85
Q

What does ciliary ganglion do? Associated nerve?

A

Eye - parasymp via CN3 to pupillary sphincter and ciliary muscle

86
Q

What does pterygopalatine ganglion do? Associated nerve?

A

Facial - greater petrosl nerve

To lacrimal glands and nasal mucosa

87
Q

What does submandibular ganglion do? Associared nerve?

A

Chorda tympani of 7, lingual nerve of V3

To submandibular and sublingual glands secretomotor

88
Q

What does stellate ganglion do? Where? Relevance?

A

Sympathetic - can be cut to reduce raynauds or hyperhidrosis sx

89
Q

What vessels usually used for AVF in ACF?

A

Cephalic vein brachial artery

Or brachiobasilic

90
Q

What is JVP vessel?

A

IJV because estimation of CVP

91
Q

Adenocarcinoma is generally what to radiotherapy?

A

Insensitive

92
Q

Which infection is associated with sulfur granules?

A

Actinomycosis

93
Q

Where does nadolacrimal duct drain?

A

Inferior meatus

94
Q

Which muscle specifically is affected by recurrent laryngeal nerve palsy? Effect?

A

Posterior cricoarytenoid - failure of abduction of vocal folds

95
Q

What cartilage is at C6? Significance?

A

Cricoid

Trachea begins below this

96
Q

What is cardiac index? Usual?

A

Cardiac output over body surface area

Usually 2.5-4

97
Q

What is only intrinsic muscle of larynx not innervated by rec laryngeal nerve?

A

Cricothyroid - ext branch of sup

98
Q

Sensation of ttachea below vocal cords?

A

Rec laryngeal nerve

99
Q

What immediate volume of blood is massive haemothorax from chest drain?

A

1500ml

100
Q

Within what distance of anal canal is AP resection suitable?

A

Lesss than 8cm

101
Q

Flow is directly proportional to what 2 things?

A

4th power of radius

Pressure head of flow

102
Q

Flow is indirectly proportional to what 2 things?

A

Viscosity

Length of tube

103
Q

Most important determination factor of flow?

A

Radius of tube

104
Q

What muscle do inf wpigastrics lie on inner surface of? What are they covered by?

A

Transcersus abdominis

Covered by parietal peritoneum

105
Q

Blood supply to breast?

A

Lat thoracic from SCA and internal thoracic/mammary from axillary

106
Q

What does anatomical neck of humerus fracture have risk of? Why?

A

AVN of head - because of circumflex vessels

107
Q

Surgical neck of humerus fracture can cause what nerve damage?

A

Axillary

108
Q

Resting myocardial blood flow?

A

250 ml per min 5%

109
Q

Borders of popliteal fossa?

A

Lateral - 2 heads of gastrocneums inferiorly, biceps femoris sup lat, semimemb/tend sup med