Other physiology Flashcards

Question

Liver physiological functions

Answer 1

Metabolic - Storage of glycogen - Breakdown of glycogen to increase glucose, glycolysis and glyuconeogeneis - lipolysis and lipogenesis - protein metabolism - storage of other compounds e.g. iron, copper - break down of drugs Immuno - kipper cells specialised macrophages antigen recognition phagocytosis Synthetic functions - albumin and plasma proteins - clotting factors Endocrine - hormones e.g. IGF-1 and angiotensinogen, hepcidin - hormone binding proteins e.g. thyroxine binding globulin - Vit d 25-hydroxilation Blood reservoir

Answer 2

Phase 1 - aim to make water soluble - more polar, hydrophilic via CYp450 - oxidation, reduction, hydrolysis - drugs then transported in plasma to kidneys and excreted Phase 2 - drugs that aren't rendered water soluble by phase 1 - addition of further group and increasing polarity - sulphation, gluroindation, acetylation

Answer 3

Pre-hepatic - bili prduced exceeds liver capacity to conjugate - unconjugated (water insoluble, negative urine) Post-hepatic - conjugated leaks into circulation - water soluble Hepatic - reduced ability to conjugate and excrete. can be conjugated and unconjugated

Answer 4

Acinus 2 porta triads and central vein in middle - zone 1 - high o2 - most energy consuming processed e.g. gluconeogenes - zone 2 - intermediate - zone 3 - least energy consuming e.g. drug metabolism

Answer 5

1/3 arterial 2/3 portal venous auto regulation to MAP of 60 via HA PV flow directly proportional to pressure gradient HA buffer response - compensate for reduced PV flow - vasodilation via adenosine extrinsic mechanisms - SNS - constrict HA - SNS activation causes benoconstriction and 250ml blood returning to circulation

Answer 6

- Antagonism of Ca CVS - reduce vascular smooth musclee tone - decreased PVR, SVR - inhibition of catecholamine - reduced myocardial contractility Resp - reduce smooth muscle tone - bronchodilator MSK - Ca responsible for nerve impulse transmission at NMJ - antagonised by Mg. Loff deep tendon reflexes, muscle paralysis, cardiac conduction abnormalities

Answer 7

circulating volume within 24hrs half circulating volume in 4 hrs

Answer 8

RBC - plasm removed, citrate adenine and glucose added. stored at 4C, 42 shelf life FFP - plasma removed from whole blood, stored at -30, 1yr shelf life. coagulation factors Cryoprecipitate - FFP frozen to -70, thawed and centrifuged. Factors VIII, XIII, fibrinogen, VwF platelet - pooled from multiple donors, room temp, 5 day shelf life, irradiated

Answer 9

haemolytic - recipients plasma contains antibodies to donor red cells leading to haemolysis - Immediate - ABO incompatibility rapid intravascular haemolysis - delayed - exposure to minor rh antigens - re-exposure delayed reaction 7-21 days later febrile non-hemolytic -recipient antibodies react with antigesn on donor leucocytes. rare since leucodepletion anphylaxis - foreign protein in donor blood cross reacts with recipient IgE TRALI - antibodies in donor blood attack recipient tissue (immune TRALI). Non-immune TRALIE - neutrophil activated GVHD - imunocompormised patient T lymphocytes in donor blood launch immune response against recipient

Answer 10

infective - septicaemia - bacterial contamination e.g. platelets stored at room temp - ID transmission - Hep, HIV non-infective - TACO - haemosierosis

Answer 11

Hypothermia (cold blood transfused) Dilutional coagulopathy (balanced protocols) Hypocalcaemia / citrate toxicity - citrate used in storage to prevent coagulation. massive transfusion --> citrate toxicity hyperkalaemia - stored blood has high K+ acidosis - stored blood has pH 6.8=

Answer 12

BMI < 18.5 underweight 18.4 - 24.9 - healthy weight 25 - 29.9 - overweight 30 - 34.9 - class 1 obesity 35- 39.9 - class 2 obesity 40 + = class 3 obesity

Answer 13

Resp - difficult airway, OSA - reduced complicance - reduced FRC (below CC) - atelectasis, V/Q mismatch - Increased O2 consumption CVS - Increased CO - Hypertension - IHD - dyslipidaemia, DM - HPVC --> RVF GI - GORD - intragastric pressure - Fatty liver and gallstones Endocrine - Insulin resistance and T2DM MSK - OA - Gout Immune - low grade inflammatory state - cancer

Answer 14

- higher difficulty with practical procedure, including access, RA, surgery, intubation - monitoring - BP cuffs - positioning - special equipment

Answer 15

PK models derived from normal weight Marsh - TBW for induction and maintenance. in morbid obesity will lead to overdose, limited to 150kg Scnider - age, height, TBW to calculate LBM, only accurate up to BMI 42 - higher maintenance infusion

Answer 16

resuscitation - glucose free crystalloid Na 131 - 154 - 10ml/kg (10-20ml/kg in neonate) maintenance - isotonic, non-glucose - 4:2:1 ml/kg/hr - 100:50:20 ml/kg/day Measure plasma electrolytes daily in neonatal period may need glucose

Answer 17

decline in physiological reserve across numerous organ systems which results in reduced capacity to compensate for external stressors - adverse outcomes - assessed by rockwood, Edmonton, timed up and go

Answer 18

Resp - Airway - edentulous - easier laryngoscopy, harder BVM. cervical spondylosis - reduced neck ext. - loss of elastic tissue - increased compliance, offset by reduced chest wall compliance (calcification of costal cartilages). - FRC increases, higher resting lung volume - weaker respiratory muscles - greater A-a gradient - V/Q mismatch, reduced diffusion capacity of alveoli CVS - stiff arteries - hypertension - greater pressure required by LV - LVH - LVH impairs relaxation, diastolic dysfunction, dependent on atrial kick - reduced Beta adrenergic activity - less increase in HR with exervise - conduction system fibrosis - arrhythmias - valvular calcification and degeneration CNS - loss of brain cells - atrophy - loss of DA - PD - cognitive impairment 20% 80+ - sensory impairment - visual / auditory Renal - reduced GFR - progressive loss of glomeruli Hepatic -reduced size and blood flow, reduced protein synthesis skin/msk - thin skin, reduced subset tissue - fragile veins - pressure sores - sarcopenia - bone deformity and thinning, arthritis

Answer 19

1. locomotion 2. posture and joint stability 3. support of soft tissues e.g. pelvic floor 4. sphincters - voluntary control over swallowing, mictuiriton 5. heat production 6. venous return

Answer 20

macroscopic - muscle fibres (myocytes) supported by connective tissue - endomysium - CT surrounding each myocyte - perimysium - surrounds 100 myocytes - epimysium - thick CT surrounding whole muscle all merge to form tendon, connecting to bone microscopic - sarcoplasmic reticulum containing calcium - t-tubules - invaginations in muscle surface memrane which relays action potential into interior - myofibrils - contractile apparatus of cell - length of myocyte, anchored to sarcolemma so when contract shortens / extends - myofilament - actin / myosin. bundles make up myofibrils

Answer 21

functional unit of the myocyte - thick filament - myosin - thin filament - actin 1:6 my-filaments regular overlapping pattern - striated appearance myosin - 2 heads , long tail, heads have actin / ATP binding site actin- double strand chains, myosin binding sites along length. two proteins lie in actin - tropomyosin (obstructs access) and troponin T / C / I. Different bands ZIAH z --> I --> A --> H

Answer 22

process of muscle fibre contraction following excitatory stimulus AP from NMJ --> depolarisation --> T-tubule --> DHPR --> SR --> Ryanodine receptor --> calcium from SR --> trop C --> tropomyosin away from actin --> myosin/actin crosslink

Answer 23

Myosin head binds ATP, hydrolysed to ADP, energised myosin head binds to actin myosin head flexes on actin binding site, pulling actin closer to centre of sarcomere myosin head binds another ATP which allows dissociation from actin crosslinking continues until intracellular calcium level drops and tropomyosin and troponin return to resting configuration

Answer 24

single alpha motor neurone and the muscle cells it innervates - single AP will cause contraction of all the myecites within the motor unit type 1 - slow twitch - postural muscles, fatigue resistant 2b - fast twitch, anaerobic - short, powerful movements

Answer 25

1. T4 - 90% of hormone released by thyroid gland. Weakly biologically active. highly protein bound to thyroxine binding globulin, long half life. 50% converted to T3. 2. T3 - 10% thyroid output. highly bound to albumin, short half life.

Answer 26

T3 regulates gene transcription in cell nucleus - increase BMR, increased availability of metabolic substrates - resp - increased MV due to increased o2 consumption and co2 production - CVS - increased CO, increased HR (increases B receptors in heart) - CNS - increased anxiety - MSK - protein catabolism and proximal myopathy

Answer 27

Thyroid gland - spheres of follicular cells, surrounding thyroglobulin Iodide uptake (secondary active transport from Na cotransporter) stimulated by TSH Iodide diffuses across follicular cell Iodide oxidised to I2 using H2O2 - promoted by TSH I2 reacts with tyrosine residues on thryoglubilin Iodination in 1 (MIT) or 2 (DIT) positions Iodidinated tyrosine residuals couple together DIT + DIT = T4 MIT + DIT = T3

Answer 28

Graves disease - Autoantibodies IgG mimic action of TSH - stimulating thyroid gland to release T3/4. also targets extraoccular muscles - proptosis, exophthalmos Hashimotos thyroiditis - autoantibodies against thyroglobulin - reduced T3/4 output

Answer 29

30 + groups Most important are ABO and rhesus ABO - carbohydrate based antigen Either - O - none A B A + B

Answer 30

Immune system develops antibodies to foreign matierial, including non-self RBC antigens - exposure to similar environment antigens - exposure to foreign RBCs e.g. following transfusion Antibodies to ABO antigens are IgM Blood group O - anti-A and anti-B antibodies A - Anti-B antibodies B - Anti-A antibodies AB - No antibodies Antibodies to rhesus D - IgG therefore cross placenta - acquired on exposure to foreign RH (fetal-metrnal haemorrhage - of blood of RH+ fetus and RH- mother mix)

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