BIOMED NOTES 24/25

Cell Counting = process of determining cells no 算细胞 importance, method, which method recommended importance of cell counting ensure accurate seeding densities 播种密度 monitors growth rates 成长 evaluates cytotoxicity or proliferation 细胞毒性与增殖 standardize experimental conditions  methods manual counting hemacytometer slide  requires a minimum of 1x10^6 cells/mL use trypan blue for viability test  viable cells not stained  cheap slow prone to error low sensitivity  electronic counting  original resistance-based counter based on the change in current generated when a cell passes through a narrow orifice 孔 image analysis software  scan stained & unstained cells in a special counting chamber & view  continuous monitoring of living cultures  work by counting cells or determine residual available growth area  rapid & low inherent 固有 error - more accurate  needs single cell suspension  flow cytometry  count by light scat...

AP = long distance GP = short  Membrane potential = electrical potential difference Ions down gradient - high to low concentration  Ion channel  leakage = non gated = open  membrane more permeable to K all type neuron ligand gated chemical ligand = neurotransmitter, hormone, ions dendrite  voltage gated  respond to direct change in MP  states: resting = inactivation gate open, activation gate close = no Na cross activated = both gate open = initiate AP = Na cross axolemma inactivated = inactivation gate close, activation gate open = no Na can pass = AP finish, return resting  mechanically gated  respond to stretch/touch, pressure, vibration Resting MP = -ve voltage - common -70Mv  Polarized = voltage difference aross PM not at 0Mv  negative ions along inside CM, positive ion outside  ECF rich NaCl  membrane more permeable to K  factors allow membrane return resting  unequal distribution of ions in ECF inability o...

Endocrine ds  Causes metabolic factor physical damage  congenital ds DM DMT1 autoimmune ds polyuria polydipsia glucosuria  DMT2 insulin resistance obesity  diabetic retinopathy diabetic nephropathy diabetic neuropathy  DI  low ADH polyuria dehydration thirst  Hypothyroidism  metabolism slow lethargy, fatigue cold intolerance weight gain loss appetite bradycardia = slow HR hyperlipidemia  Hyperthyroidism metabolism speed up heat intolerance weight loss increase appetite hyperreflexia tachycardia = abnormal HR Goiter enlarged thyroid gland high TSH unable to produce TH iodine deficiency  Grave's ds autoimmune ds high TH iodine load hyperthyroidism  Addison's ds primary adrenal insufficiency  autoimmune ds insufficient cortisol low aldosterone high ACTH Cushing's syndrome high cortisol  cause: corticosteroid medication hypertension DM Moon face Buffalo hump  Acromegaly  high GH no increase height bone size increase ...

Endocrine & Nervous rely on release of chemicals share many chemical mssger  regulated primarily by -ve feedback  common goal: to preserve homeostasis by coordinating & regulating activities of other cells, tissues, organs, systems  Hormone class peptide range from short polypeptide chain of aa to small proteins  water soluble = hydrophilic  cell surface receptor  insulin, glucagon, ACTH, PTH, TRH, GH steroid/lipid derivatives eicosanoid or cholesterol  lipophilic  + ic receptor  release by gonads, adrenal gland  estrogen, progesterone, corticosteroid  amino acid derivatives  tyrosine & tryptophan  TH catecholamine - EP, NE, dopamine Trp - melatonin  Water-soluble hormone action act on receptor in PM receptor coupled via G protein to >1 IC 2nd mssger mediate target cell response Insulin, glucagon hormone + receptor + G protein  ATP to cAMP  open ion channel & activate enzymes GHIH hormone ...