Cell phys. Vosco lecture 1 Flashcards by Duke A

The Sodium- Potassium Pump:
• Maintains Na+ K+ concentration gradient
•Requires ATP
•___ Na+ out for __ K+ in
•Makes resting membrane potential more negative

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Ions will flow until:
•______ _______ (equilibrium potential is
reached)
•There is a physical barrier that prevents ionic flow from continuing (______-gated channels)
• Nernst potential of potassium = -90
• Nernst potential of sodium = ____
• Nernst potential of chloride = -70

Nernst potential

voltage

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____ dictates the resting potential of the cell

potassium

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There are two types of postsynaptic responses to neurotransmitters released to the synapse

Graded responses
–EPSPs
•Mediated by \_\_\_\_ influx
–IPSPs
•Mediated by \_\_\_\_influx
•Action potential
– All-or-none
–Action potentials are the sum result of graded responses, but only to a certain point

Na+

Cl-

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Ionotropic = ______-gated (faster)

ligand

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Metabotropic binding = __-____ _____(slower)

Metabatropic is also known as:
1. _______
2. Muscarinic

G-protein coupled

GPCR

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membrane potential = ___Mv

trigger zone = ______

-55

Hillock

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voltage gated _____ channels open at -55Mv which work with voltage gated ________ channels causing an increase in sodium and decrease in potassium in the cell

sodium

potassium

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the action potential has properties specific to the ion channels that carry it… so in the graph sodium channels open –> more sodium channels open –> sodium channels close and potassium channels open causing repolarization–> potassium channels close at about ___Mv

-70

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voltage gated sodium channels = _____ ______ ______

Voltage gated potassium channels = ______ _______ ______

Absolute refractory period

relative refractory period

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_________ is the term used to describe the degree to which ion channels are open for a given area on the cell membrane
__________ is the inverse of resistance
Increasing diameter increases the number of ion channels that can fit in an area and thus increase its conductance

Conductance

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______ conduction is when the current only enters through unmyelinated portions of the axon. i.e. ____ __ _____

Saltatory

Nodes of Ranvier

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•Vesicles are tied to the active zones by docking proteins, including ____ and synaptophysin
•When AP is generated toward the terminal
end of the axon, voltage gated ___ channels are opened
•Ca2+ causes actin to contract, brings vesicles forward to the membrane. Also, ca2+ activates ______, which causes expulsion of contents of vesicle into the cleft

actin

ca2+

calmodulin

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A fixed amount of neurotransmitter is

released for each Action Potential; this is known as _____

quanta

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• Amino acids
–Aspartate

–\_\_\_\_\_\_\_\_—most prevalent excitatory NT
•Ionotropic (ie ligand-gated)
–AMPA— \_\_\_\_ influx
–Kainate
– NMDA—Requires depolarization, some Mg2+ and then Na+ and Ca2+ influx in addition to glutamate binding

•Metabotropic—big variation. Over 100 subtypes
–MGLURs

Glutamate

Na+

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–GABA—most prevalent inhibitory NT
•Ionotropic
–_____ A—Cl-influx

GABA

faster

IPSPs

Glycine— found all through the body. Synthesized form ______ via _______. Particularly active in spinal cord.

glucose

serine

Glutamate and GABA are both recycled with help from ________

astrocytes

Biogenic amines–Acetyl choline(Ach).
•All motoneurons on _____ muscle use Ach.

•Degraded by acetyl _________.

•______ (ionotropic)— skeletal muscle. Na+
and Ca2+ influx.
–More nicotonic in PNS

•________ (metabotropic).
–More muscarinic in CNS and smooth muscle

skeletal

cholinesterase

Nicotinic

Muscarinic

–Dopamine
»D1 (Excitatory) and D2 (Inhibitory) receptors
** both of the above are ________

»GPCRs
»Two major areas are from SUBSTANTIA NIGRA and VENTRAL TEGMENTAL AREA (VTA)
»Substantia nigra is involved with basal ganglia circuit and loss of dopamine here is cause of ________ Disease
»VTA involved with both addiction and
schizophrenia

metabatrophic

Parkinson’s

Monoamines–catecholamines
–Norepinephrine
»Produced in the _____ ______ in the pons
»All about arousal alertness and attention
»PNS sympathetic neurotransmitter
»2 alpha and 2 beta receptor
subtypes (both are _______)

-beta receptors can bind ______ pretty well

Locus Ceruleus

metabatrophic

epinepthrine

•\_\_\_\_\_\_\_ ( 5-HT)
–Related to depression, pain inhibition
–Raphe nuclei of the brainstem (midbrain)
–At least 7 different receptor subtypes
–SSRIs

Serotonin

electrical synapses are also known as ____ _______

-______ links 2 dendrites together

gap junctions

conexins

Glia
• _______: glucose delivery, blood brain
barrier, inflammatory response, ATP release,
glutamate recycling

•___________: myelinate axons in the central nervous system

• Microglia: major immune response,
phagocytosis
** microglia is derived from ______

•Ependymal cells: help produce and move
____ through the brain

Astrocytes

Oligodendrocytes

monocytes

CSF

sensory system --> _______ -->change in energy effectors= ______ and glands

transduction muscles

Peripheral fibers named according to myelination and axonal thickness ``` •“A”:myelinated sensory and motor fibers –Alpha: LMNs – Beta: Sensory receptors for light touch, pressure –Gamma: Axons to intrafusal fibers –______: sharp pain, cold ``` •*In “A” fibers, the “A” is often omitted and only the greek letter is used to describe the subtype •“B”:________ visceral fibers: preganglionic autonomic • “C”:Unmyelinated fibers: post ganglionic autonomic, slow pain, heat, itch **these are arranged from fastest to slowest**

Delta myelinated

``` •I –Ia: Muscle Spindles –Ib: _____ _____ _____ •II—Same as A-Beta or A-Gamma Fibers •III— Same as A-Delta or B Fibers •IV— Same as C Fibers ``` ** arranged from fastest to slowest**

Golgi Tendon organs

somatic motor neurons travel from the ventral horn to the motor end plate (neuromuscular junction) and ___acts on the effector which is _______ then theres contraction of skeletal muscle

Ach nicotinic

autonomic motor neurons travel from the lateral horn to an autonomic gagnglion where theres Ach then this travels to postganglionic neuron and works with ___ (muscarinic) and ___ (alpha or beta) then theres smooth muscle contraction or glandular secretion

Ach NE

receptor potentials =_____ and _____ Generator potentials = action potential specific to receptor terminals

EPSP IPSP

* Nicotinic receptors between Pre and post ganglionic * Muscarinic are on all ______ cells * Sweat glands are exception to the NE-Ach rule

effector

______ are the individual contractile fibers of the muscle

Sarcomeres

* Part of myofibril, between two Z Discs * Z DISC or Z lines= filamentous proteins, borders of sarcomere * I bands= ONLY ____ filaments * A bands= all of myosin filaments and portion of _____ overlap * H zone= ONLY ______, no actin overlap (disappears during contraction)

ACTIN actin MYOSIN

Binding of _____ to troponin moves tropomyosin, exposes myosin binding site on actin. this is known as _____-_____ coupling.

Ca2+ excitation-contraction

in the ear; the intracellular ions are ______ and the extracellular ions are _______

sodium potassium

______ tells up and down direction and the ______ relates side to side acceleration

sacule utricle