Cellular Physiology Pt 2 Flashcards
Atrial natriuretic peptide (ANP) and nitric oxide (NO) act through _________ that converts GDP to _________ which is the second messenger
Guanylyl cyclase; cyclic GMP
Insulin acts through _____ _____
Tyrosine kinase
Associated with enzymatic activity in receptors (no G proteins)
Catalytic receptor mechanism
How do beta 2 stimulants affect lungs?
Terbutaline— acts on receptors via Gs protein, activates adenyl cyclase which increases cAMP.
cAMP activates protein kinases which cause brinchodilation
How do phosphodiasterase inhibitors affect lungs? (Aminophylline)
Inhibit breakdown of cAMP, meaning increased cAMP levels, more protein kinase, bronchodilation
How does ipratropium (Atrovent) affect lungs?
Inhibits inhibits M3 (cholinergic miscarinic) receptor leading to bronchodilation
What causes bronchoconstriction?
Stimulation of M3 receptor and G protein causes formation of IP3 which releases Ca from ER
cAMP Mechanism drugs/hormones
ACTH LH, FSH TSH ADH (V2 receptor) HCG B1 & B2 receptor A2 receptor Calcitonin PTH Glucagon Muscarinic (M2)
IP3 mechanism list
GnRH TRH GHRH ADH (V1 receptor) Oxytocin A1 receptor Angiotensin-II Muscarinic: (M1, M3)
Steroid hormone mechanism list
Glucocorticoids Estrogen Testosterone Progesterone Aldosterone Vitamin D Thyroid hormone
Activation of tyrosine kinase
Insulin
IGF-1
cGMP
Nitric oxide (NO) ANP
Opening of Na/K pump channels
Nicotinic:
Nm (N1)
Nn (N2)
Upstroke of action potential
Na moving into the cell
Downstroke of action potential
K moving out of the cell
What causes resting membrane potential?
Leaky K channels
Absolute refractory period
Period when another action potential CANNOT be elicited
Relative refractory period
Period when an action potential can be elicited by larger than usual stimulus
________ protects the cell from over-excitation and allows a recovery period between the action potentials
Refractory period
______ inhibit Na/K pump leading to hyperkalemia
Beta blockers
Are continuous with the cell membrane
Invaginate the cells at the Z lines and carry AP into the cell interior
T tubules
Site of storage and release of Ca++ for excitation-contraction coupling
Sarcoplasmic reticulum
______ block entry of Ca in L-type calcium channels. How does it affect HR?
CCB; HR slows down
Why do cardiac cells not respond to tetanus?
They have high refractory period and will not respond to the stimuli
A series of myosin head movements that result in sustained contraction
Tetany
MOA dobutamine
Beta agonist
Increases cAMP, activation of protein kinase, increased Ca into myocardial cell, increased force of contraction
MOA beta blockers
Inhibit Na/K pump. K stays extracellular and can cause hyperkalemia
Caffeine, aminophylline, milrinone MOA
Phosphodiasterase inhibitors. Decrease breakdown of cAMP
Diltiazem MOA
CCB. Block entry of Ca through L-type (dihydropyridine receptors) channels. Decreases HR
Dantrolene MOA
Blocks Ca release channels (ryanodine receptors) on sarcoplasmic reticulum
