high yield concepts for molecular/ cell physiology

[Anonymous]

1) Damage to nucleus - cell is always going to die (Ischemic injury, Hemorrhagic injury, granulomatosis)
2) Irreversible cell death- takes 6 hours for every cell in the body except brain hypoxia.
3) Know secondary transport esp secondary active co- and counter transport examples.
4)Concentration gradiet of ions like Na, K, cl, you will answer every question on it right. Any injury will affect concentration gradient. Also, limiting factor for fat soluble substances is concentration gradient.
5) Signal transduction
Protein hormone question- pick up 2nd messenger as choice most common by default is Gs alpha, ignore choices on DNA or RNA (these are for steroid hormones)
Steroid hormones- stimulate DNA, RNA protein synthesis, so ignore choices on 2nd messengers and look for protein choices on exam.
IP3/DAG- all hypothalamic hormones except CRH (Gs alpha), M3 receptors, Motilin
Ca-calmodulin- smooth muscle contraction, bladder, uterus at term, blood vessel in hypertension.
NO- ANP, nitrates, viagra, endotoxin.
Tyrosine kinase- insulin, growth hormone, IGF-1, all groeth factors in body, somatomedin.
6) Hyperkalemia- causes memb pot and equilibrium pot. is +ve (cell depolarize), so memb conductance increases.
7) Permeable substances- are lipid soluble gaseous (oxygen , nitrogen >urea>glycerol>glucose>Na.
Mem b permeability depends on size of molecule, lipid solubility, charge (main factors)
8) injection Ach decreases BP because of increase Nitric oxide release
Injection of NE causes increase in BP because of activation of phopholipase C in arteriolar smooth muscle.
9) lipophilic hormone will bind to which receptor? Steroid receptor.
10) if you block Na channel what will happen? Cell will not depolarize.
11) Atherosclerotic patient with high cholesterol where will you find it in blood vessel? They show a histology section…. Point to macrophage guys…..which receptor is upregulated? Scavanger receptor because cholesterol bings through these receptors via lipoproteins.

High yield concepts for USMLE- basic yet KEY CONCEPTS TO REMEMBER.