physiology BRS by Costanzo summary

Cell physiology:

 Cell membrane:
 Composed of phospholipids and proteins.
 Lipid bilayer:
 Phospholipids with glycerol.
 Lipid soluble substances (O2,CO2 and steroid hormone)
 Water soluble substances (Na+, Cl-, glucose and H2O)
 Proteins:
 Integral proteins: nachored and imeded in the cells membrane through hydorphbic
interaction. And it spans the cell membrane. Such as Ion channels, transport protein.
Receptors.
 Peripheral proteins: not imbedded, not covalent binded and loosely attached
through electrostatic interaction.
 Intercellular connections:
 Tight junctions: zona occludens
 Attachment btw cell. Tight in the renal DCT. And leaky in the PCT, gallbladder.
 Gap junctions: permit interceullar communication.
 In the cotransporter and counter one there is inhibition of the ATP Na+ pump.
 Transport across cell membrane:
 Simple diffusion:
 Not carrier mediated.
 Down the electrochemical
 No energy needed





 Permeability:
 Ease of the solute to diffuse through membrane.
 Increase by decrease radius of the solute, increase the oil/water partition, and
decrease the membrane thickness.
 Carrier mediated transport:
 It is stereospecific.
 Has saturation limit.
 Has competition for molecules.
 Facilitated diffusion:
 Down electrochemical.
 Passive.
 Rapid than simple diffusion and carrier mediated one. i.e. glucose in insuline
response
 Primary active transport:
 Against electrochemical.
 Needs energy. Carrier mediated. Such as Na+/K+, Ca2+ pump and H+,K+ pump.
 Secondary active transport:

,  Coupled transport. Symport (Na+, glucose) vs antiport( Na+, Ca2+)
 Osmosis:
 Osmolarity:
 Can be measured by freezing point depression.
 Osmosis: is the flow of the water across semipermeable membrane according to the
gradient.
 Calculating the osmotic pressure.





 It increases when the amount of solutes increases.
 Reflection coeffieient if is One it is not Permeable. If is Zero it is Super Permeable.
 AP, RMP and diffusion potential:
 Ion channels:
 Integral proteins.
 Selective ones.
 Voltage gated channels: responds to change in tehj membrane potential.
 Ligand gated channels respond to the hormones and second messenger.
 Diffusion and equilibrium potentials:
 The size diffusion potential depends on the difference of the concetration gradient





 Resting membrane potential:
 -70 mV.
 Na+/K+ pump contribute indirectly.
 Results form the difference in the pearmeation potential to the diffusion of ions.
 Action potentials:
 Depo, makes the membrane potential less negative.
 Hyperpola, make it more negative.
 Accommodation occurs when the cell membrane is held at depolarized levels.
Without firing AP. Due to inacitavton of Na+ channels. Seen during hyperkalemia.

, 
 Spatial summation when two AP arrive at the same time to the postsynaptic junction.
 Temporal when we have different timed interval AP generated.
 Dopamine:
 D1 receptor work by activation adenylase cyclase thru Gs proteins
 D2 receptor inhibit adenylase cyclase thru Gi protein.
 Parkinson disease involves the degeneration of D2 receptor.
 Schizophrenia involves increase D2 receptor.
 Serotonin: from tryptophan and converted to melatonin.
 GABA:
 Gaba A works thru Cl- conductance.
 Gaba B work thru K+ conductance.
 Skeletal muscle:
 Muscle fibers has bundles of myofibrils. Surrounded by SR, and invaginated by T tubules.





 Thick filament: has myosin. With the two heads attach to single tail.
 Thin filament contain actin. With troponine and tropomyosin
 Tropomysin has 3 segments. T attached to tropomyosin. I inhibits interaction, actin,
and myosin. C Ca2+ bind protein.
 Isometric contraction is the length
is constant, no shoretening.
 Isotonic contraction isteh load
held is constant and there is
shortening of the muscle.




 Neurophysiology:

,  Autonomic nervous system:
 Set of pathway from CNS to regulate Smooth muscle, Cardiac muscle and Glands.
 Organization of ANS:
 Parasymp ganglia located near the effector organ
 Symp ganglia located near the paravertebral chain.
 Preganglionic neurons: have their cell bodies in CNS and synapse in autonomic ganglia.
 Preganglionic of sympathetic nervous originated from T1 to L3 thoracolumba .
 Preganglionic of the parasympathetic nervous system originated form sacral part S2-S4
and craniosacral part.





 Neurotransmitter of the ANS.
 Adregenic neuron secrets Norepinephrine.
 Cholinergic neurons which secrets acetylcholine.
 Nonadregenic, Noncholinergic releases substance P, VIP, NO.
 Receptors types in the ANS:
 a1 Receptors: located in the vascular smooth muscle. Of skin and splanchnic regions. GI,
Bladder sphincter and iris. Prduce contraction. Acts thru Gq protein to increase
phospholipase C and thus increase in IP3 and Ca2+.
 a2 Receptors: on the symp. Postganglionic nerve terminals. Platelets, fat cells. And the
wall of GI. Produce inhibtion. Thru Gi. Decrease in cAMP,
 B1 receptors. Located in the SA, AV, nodes and ventricular muscle of the heart. Produces
contraction. Thru Gs and increases cAMP.
 B2 receptors: located on the vascular smooth
muscle of the skeletal, bronchial, and GI, bladder
walls. Produce relaxation /dilation . thru Gs
increase cAMP.
 Cholinergic receptors:
 Nicotinic receptors: located in the
autonomic ganglia, of neuromuscular and
adrenal medulla. Activated by
acetyl/nicotine. Produces excitation.
 Muscarinic receptors: M1 nervous, M2
heart, M3 smooth and glands. Inhibitory in
heart(Gi). Excitatory in smooth and glands
(Gs). Activated by muscarin/acetyl.
 Autonomic centres: