Valley Module 1 a - Cell Physiology Flashcards
what does not diffuse through lipid bilayer
large water soluble molecules & Ions ( ions are least likely to penetrate lipid bilayer)
give example of pinocytosis?
proteins reabsorbed from the proximal tubule of the kidney
give example of phagocytosis
macrophages phagocytize bacteria
give exocytosis example
neurotransmitters are released from the nerve terminals
what is a ligand & give examples
what attaches to a ion channel ( iontropic receptor)
- ligand is a chemical, drug, neurotransmitter or hormone
- 5ht3, GABAa, Glutamate
what are metabolic receptors & give examples
- receptors that control membrane bound enzymes
- GPCR & most adrenergic receptors ( adrenergic becuase they use adrenealine)
what are catalytic receptors & give examples
Insulin, EPO, ANP, Growth factors
- most are enzyme themselves or part of enzyme cascade
what are nuclear receptorss & give examples
Steriod hormones
- located in cytosol & nucleus
what is result of Na K ATPase Pump
3 Na move out & 2 K move in
why give insulin in hyperkalemia
Insulin moves K into cell by stimulating Na-K pump.
talk about Beta 2 agonist & Na -K pump
Beta 2 adreneric agonist stimulate Na K pump (like ritodrine & terbutaline). and thus get hypokalemia
what do G proteins do?
relay or shuttle messages from receptors to enzymes
name some 2nd messengers?
cAMP, cGMP, calcium, calmodulin, IP3, DAG
why must we know what tissue we are in
2nd messengers produce different repsonses in different tissues, like in heart cAMP increases Ca and contractility, but in bronchial smooth muscle increased cAMP decrease Ca and produces bronchdilation
what is so important about 2nd messengers
second messenger action is tissue specific
Gs and adenylate cyclase
increase contractility from B1 and bronchdilation from B2 both use Gs & AC.
what are steps of cAMP 2nd messenger?
- Ligand binds
- receptor activates G protein
- G protein activates adenylyl cyclase
- ATP –> cAMP by AC
- cAMP make protein kinase phosphoralte protein
- tissue specific response
examples EPI & Ach
what are steps of Ca 2nd messenger?
- ligand binds
- activates G protein (Gq)
- activates Phospholipase C
- Phospholipase C becomes IP3 & DAG
- IP3 releases Ca
Bronchoconstriction
How does NO (Nitric Oxide) work?
activates cGMP by diffusing through membrane, does not bind outside.
get Bronchodilation
hwo do NTG & Nitroprusside affect bronchus?
promote bronchodilationby increasing concentration of cGMP.
how does IP3 cause an effect?
IP3 from M3 receptor stimulation results in conversion of PIP2 to IP3 by Phospholipase C. IP3 release Ca which promotes Bronchoconstriction.
What medications can block M3 in the lungs
Atropine & Ipratropium (Atrovent) block M3 and cause bronchodilation
which first messenger dose not bind to a cell membrane receptor
NO diffuse thru the cell to turn GTP to cGMP
(just as ATP becomes cAMP)
which substance least penetrates lipid Bilayer
IONS
