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
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
3
Q
What shift does fetal Hb cause in o2 Hb curve?
A
Left
4
Q
pH of venous blood normally?
A
5.33
5
Q
What do kupffer cells of liver do?
A
Recycle old red blood cells
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
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
8
Q
Where is calcium absorbed in GI tract?
A
Duodenum
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
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
11
Q
What secretes platelet derived growth factor? 2 things
A
Macrophages
Endothelium
12
Q
What is the blood supply to atheromatos plaque called?
A
Vasa vasorum
13
Q
Bph stands for?
A
Benign prostatic hyperplasia
14
Q
What does thymus do?
A
Receives immature T cells and does positive and negative selection
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
16
Q
When does granulation tissue appear in wound healing?
A
Regeneration phase - day 5 to 56
17
Q
Stage 1 of haemorrhagic shock?
A
Less than 750 ml blood (15%)
Normal everything, normal or high pulse pressure
18
Q
What is circulating volume in L approx?
A
5L
19
Q
Stage 2 of haemorrhagic shock?
A
750-1500 mls 15-30%
Tachycardia, falling pulse pressure, mild high RR but normal BP
20
Q
Stage 3 of haemorrhagic shock?
A
1500-2000mls 30-40%
Tachy over 120
Bp drops
Confused
21
Q
Stage 4 of haemorrhagic shock?
A
Anuric less than 5 ml per hour
BP drops
Lethargic and drowsy
22
Q
If BP drops which stage of haemorrhagic shock?
A
At least 3
23
Q
If tachycardia with decrease pulse pressure which stage of haemorrhagic shock?
A
At least 2
24
Q
What is type 2 hypersensitivity? Examples?
A
Cytotoxic- IgG/M against cell surface antigens e.g. ABO incompatibility/AIHA, Goodpastures
25
Type 3 hypersensitivity? Examples?
Immune complex IgGMA deposition, soluble antigens, e.g. SLE or aspergillus
26
Type 4 hypersensitivity? Examples?
T cell mediated delayed immune
| E g. Granuloma formation, contact dermatitis, GVHD
27
Mnemonic for types 1 to 4 hypersensitivity?
```
A naphylactic
C ytotoxic
I mmune complex
D elayed immune
Has bad allergies
```
28
3 phases of secretion of gastric acid? Mediators?
Cephalic (smell/taste) - vagal mediated Hcl and gastrin release
Gastric (stretch) - gastrin release
Intestinal (duodenal food) - CCK and secretin
29
3 factors increasing gastric acid secretion?
Gastrin
Vagal nerve stimulation
Histamine
30
3 things reducing gastric acid secretion?
CCK
Secretin
Somatostatin
31
How does somatostatin reduce gastric acid release?
By inhibiting histamine
32
What secretes gastrin? What does it do?
G cells
Increases HCl pepsinogen and IF secretion
Increases gastric motility and emptying
33
What secretes CCK? What does it do? In response to?
I cells in upper duodenum in response to fat TGLs and protein
Delays gastric emptying increases pancreatic secretions and causes gallbladder contraction
34
What secretes secretin? What does it do?
S cells in duodenum
| Increases pancreatic secretions in response to acid and chyme
35
What does VIP do and where is it secreted?
Small intestine and pancreas - increase pancreatic secretions in response to neural stimulation
36
What secretes somatostatin? What does it do?
D cells in pancreas and stomach
| Stops everything basically, inhibits histamine and produces mucous
37
Which part of the immune system is complement involved in?
Innate immune system
38
Which part of the complement system is involved in response to pathogen surfaces?
MBL
39
What arr the 3 parts of complement system?
Classic - Ag/Ab complexes
Alternative - activating surfaces e.g. pathogen or injured tissue
MBL - direct response to pathogen surfaces
40
What is classical complement system activated by?
AgAb complexes
41
What is alternative complement system activated by?
Surfaces e.g. injured tissue or pathogen
42
Which part of complement system activates mast cells?
Anaphylotoxin - C5a
43
Which part of complement system primes opsonization for phagocytosis?
C3b
44
What is main complement mediator for inflammation and chemotaxis?
C3a
45
What forms the MAC in complement and what pathway is this called?
C5b to c9
| Lytic pathway
46
MAC Deficiency can lead to which infections?
Neisseria and gram negatives
47
What innervates long head of triceps and what does it do?
Radial nerve - stabilises shoulder in abduction
48
What cord and roots form radial nerve?
Posteiror cord
| C5 to t1
49
What is the branch of the radial nerve in the arm innervating supinator, extensor carpi radialis longus and brevis and abductor policis longus?
Posterior interosseus
50
What nerve innervates brachioradialis?
Radial
51
7 things innervated by radial nerve?
```
Triceps
Brachioradialis
Supinator
Extensor carpi radials
Extensor carpi longus and brevis
Abductor policis longus
```
52
What is the extrinsic pathway activated by? What does this do?
Tissue factor
| Activates 7 to 7a
53
Which test measures extrinsic pathway?
PT
54
Which test measures intrinsic pathway?
APTT
55
What activates intrinsic pathway? What does this do?
Exposed collagen via tissue injury
Does TENET
Twelve Eleven Nine Eight Ten activation
56
What is the joint goal of intrisnic and extrinsic coag pathways?
Activating factor 10 for the common pathway
57
What does factor Xa do? What helps it?
Actiavtes prothrombin to thrombin (2 to 2a)
| Reauires factor 5 to 5a and calcium
58
What does thrombin do in coag cascade?
Activates fibrinogen to fibrin (1 to 1a)
59
What clotting factor cross links fibrin to form clot with platelets?
13a
60
How do protein C and S work? What do they do? Relation between warfarin and protein C?
Modulate coag cascade - anticoagulants
| Warfarin inhibits protein C to transients make clotting more likely
61
Where are the cell cycle stop checkpoints? What are they?
G1, S/G2 and M
G1 - restriction point, go to G0 fails
S/G2 - Dna damage checkpoint
M - spindle checkpoint
62
Outline PMAT?
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
Where is carotid body? What about carotid sinus?
Body is behind carotid bifurcation
| Carotid sinus is at origin of ICA
64
What type are carotid body receptors and what are the stimulated by primarily? To cause what?
Chemoreceptors stimulated primarily by low O2 to stimulate ventilation
65
Hormonal control of lactation?
Prolactin causes development of breast, mammary gland proliferation, milk production following suckling
Oxytocin causes contraction and milk expulsion in response to suckling
66
What does PTH do to phosphate?
Reduces reabsorption in PCT to lower level
67
Where is most phosphate reabsorbed in kidney?
PCT
68
Why does PO rise in AKI?
Less filtration
69
How does calcitonin lower calcium?
Suppresses osteoclast activity to reduce bone breakdown
70
With what percentage of stenosis is carotid endarterectomy indicated?
Over 70%
71
Which antibody type is involved in alternative complement payhway?
IgA
72
At which spinal level is ampulla of vater?
L2
73
What do alpha receptors do?
Vasoconstriction peripherally
74
What do beta receptors do?
Positive chronotropism and isotropic for heart
| Also bronchodilation
75
How does norad work?
Peripheral vasoconstriction via alpha agonism
76
How does dobutamine work?
Beta 1 agonism - increases contractility and cardiac output
77
Around what days does spinal cord extend rostrally and caudally in development?
D 24 and 26 respectively
78
What is a Jefferson fracture?
Bilateral C1 fracture anteiror and posterior due to axial loading
79
What is a hangman's fractufe?
Bilateral pars fracture due to hyperextension
80
Describe the low and high dose dexamethasone test?
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
What suggests cushings disease in dex suppression test?
High dose suppresses but not low
82
What if cortisol not suppressed by high or low dose dex? What to check then?
Suggests not Cushings disease - check ACTH. If high suggests ACTH oma e.g. ectopic lung, if low suggests primary hypercortisolism
83
What is cushings disease?
ACTH secreting pituitary adenoma (secondary hypercortisolism)
84
What does otic ganglion do? Associated nerve?
Parasymp to parotid
| CN 9
85
What does ciliary ganglion do? Associated nerve?
Eye - parasymp via CN3 to pupillary sphincter and ciliary muscle
86
What does pterygopalatine ganglion do? Associated nerve?
Facial - greater petrosl nerve
| To lacrimal glands and nasal mucosa
87
What does submandibular ganglion do? Associared nerve?
Chorda tympani of 7, lingual nerve of V3
| To submandibular and sublingual glands secretomotor
88
What does stellate ganglion do? Where? Relevance?
Sympathetic - can be cut to reduce raynauds or hyperhidrosis sx
89
What vessels usually used for AVF in ACF?
Cephalic vein brachial artery
| Or brachiobasilic
90
What is JVP vessel?
IJV because estimation of CVP
91
Adenocarcinoma is generally what to radiotherapy?
Insensitive
92
Which infection is associated with sulfur granules?
Actinomycosis
93
Where does nadolacrimal duct drain?
Inferior meatus
94
Which muscle specifically is affected by recurrent laryngeal nerve palsy? Effect?
Posterior cricoarytenoid - failure of abduction of vocal folds
95
What cartilage is at C6? Significance?
Cricoid
| Trachea begins below this
96
What is cardiac index? Usual?
Cardiac output over body surface area
| Usually 2.5-4
97
What is only intrinsic muscle of larynx not innervated by rec laryngeal nerve?
Cricothyroid - ext branch of sup
98
Sensation of ttachea below vocal cords?
Rec laryngeal nerve
99
What immediate volume of blood is massive haemothorax from chest drain?
1500ml
100
Within what distance of anal canal is AP resection suitable?
Lesss than 8cm
101
Flow is directly proportional to what 2 things?
4th power of radius
| Pressure head of flow
102
Flow is indirectly proportional to what 2 things?
Viscosity
| Length of tube
103
Most important determination factor of flow?
Radius of tube
104
What muscle do inf wpigastrics lie on inner surface of? What are they covered by?
Transcersus abdominis
| Covered by parietal peritoneum
105
Blood supply to breast?
Lat thoracic from SCA and internal thoracic/mammary from axillary
106
What does anatomical neck of humerus fracture have risk of? Why?
AVN of head - because of circumflex vessels
107
Surgical neck of humerus fracture can cause what nerve damage?
Axillary
108
Resting myocardial blood flow?
250 ml per min 5%
109
Borders of popliteal fossa?
Lateral - 2 heads of gastrocneums inferiorly, biceps femoris sup lat, semimemb/tend sup med
