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Flashcards in M&R Deck (37)
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What is hereditary spherocytosis? Pattern of inheritance

Autosomal dominant

Sphere shaped RBCs, more prone to rupture --> anaemia.


What is hereditary elliptocytosis? Pattern of inheritance?

Autosomal dominant

elliptical RBCs, prone to rupture -- > anaemia. Caused by defect in cytoskeleton meaning the RBCs do not return to their usual shape after leaving microvasculature


What cells myelinate peripheral axons and CNS axons?

Peripheral - Schwann

CNS - oligodendrocytes


What 3 factors affect conduction velocity?

  1. Membrane capacitance - ability to hold charge
  2. Membrane resistance - high resistance = high conduction velocity
  3. Axon diameter


How does an AP at the presynapse result in AP at the post synapse?

  1. Calcium comes in
  2. Binds to synaptotagmin
  3. Results in vesicle brought to membrane and snare complex forming
  4. Neurotransmitter release
  5. Binds to receptors on post synapse


What are the 2 types of blockers of nicotinic receptors?

Depolarising and competitive.

Depolarising blockes - depolarise the membrane over a long period of time and inactivate any nAChRs, preventing new APs.


Where is calcium stored in the cell? How can it be released from its stores?

Stored in ER

  1. GPCR activated --> IP3 --> IP3 receptors on ER --> Calcium release
  2. Calcium induced calcium release - T tubule depolarised --> activated of VOCC --> calcium in subplasmalemmal area --> activates ryanodine receptors in SR membrane.


Give the 4 ways a lipid molecule can move in a lipid bilayer

  1. Flexion
  2. Rotation
  3. Diffusion
  4. Flip flop


How does cholesterol increase membrane fluidity

Reduced phospholipid packing

Stabilises membrane by H bonding


What is the RBC cytoskeleton made up of?

Actin and spectrin bound to membrane by ankyrin and glycophorin


How does diarrhoea occur?

Phosphorylation of CFTR results in excess loss of Cl- and therefore water


Explain phagocytosis, pinocytosis, and receptor mediated endocytosis

phagocytosis - ligand binds to receptor on phagocyte, results in zipper mechanism 

Pinocytosis - PM invaginates and internalises molecule

RME - Ligand binds to receptor and recruits clathrin coated pits to internalise it.


Explain RME using cholesterol as an example. How does it differ for transferrin containing iron ions and insulin?

  1. LDL binds to LDL receptor on surface
  2. Clathrin coated pit recruiting and phagosome forms
  3. Fuses with endosome, low pH causes dissociated of LDL and receptor.
  4. Receptors recycled and endosome fuses with lysosome for digestion

Same for transferrin. With insulin both receptor and insulin degraded. 


What are the adrenergic and cholinergic receptors linked to: alpha, inhibitory or stimulatory g proteins? What does each g protein do?

Adrenergic Q - alpha 1 - Galpha

                     I - alpha 2 - Ginhib

                    S - beta 1 - Gstim

                    S - beta 2  - Gstim


Cholinergic Q - M1 - Galpha

                      I - M2 - Ginhib

                     Q - M3 - Galpha


Galpha - +PLC

Ginhib - (-AC)

Gstim - (+AC)


What is the kd of a drug?

dissociation constant 

concentration at which 50% of the receptors are occupied


What is the Emax and EC50 of a drug?

Emax - Conc of drug needed to get 100% response

EC50 - conc of drug needed to get 50% response.


What is affinity and efficacy of a ligand?

Affinity - how easily it binds

Efficacy - How good it is at effective a response from the receptor.


What is a partial agonist?

a ligand that cannot amount a 100% response


What are class 1 and class 2 drugs?

Class 2 drugs - bind to albumin to allow class 1 drugs freedom to act

Class 1 drugs - Object drug


What is first order and zero order kinetics? When does each take place?

First order - Fraction of drug eliminated per unit time. Occurs when conc of drug is less than Km

Zero order - Rate of elimination is constant per uni time. Occurs when conc of drug is greater than Km


How does pH affect how much drug is excreted?

if drug is acidic and urine acidic reabsorbs more drug and vice versa


What enzymes breaks down ACh and NA in cleft?

ACh - acetyl cholinesterase

NA - monoamine oxidase


What is tachyphylaxis?

Reduced sensitivity to a drug due to repeated exposure.


where are phospholipid made



what are integral rbc proteins

Ban 5

glycophorin A


give example peripheral RBC proteins

spectrin and actin


what is function of ribophoryn

anchors ribosome to RER


how can phospholipid move

flex, rotate, lateral diffusion, flip flop



actions of cholesterol

increase fluidity by decrease phospholipid packing. decrease fluidity by decrease phospholipid motion. prevents cell state changing


how can membrane protein move

rotate, conformational change, lateral diffusion