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Phys-3
NEUROPHYSIOLOGY: GENERAL PRINCIPLES & SENSORY PHYSIOLOGY
20
Physiology
Graduate
10/14/2011

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Term
What are the two types of synaspes? Describe each.
Definition

a.Chemical-almost all CNS synaspes, axonal ends secrete NT, NT can be stimulatory or inhibitory

b. Electrical-rare in CNS, signal transmission via gap junctions 

Term
What is the Ionophore component?
Definition
A component of the a postsynaptic receptor protein that extends inside through the membrane of the cell and acts as either a ligand-gated ion channel or second messenger activator 
Term
Excitatory receptors most commonly openswhat and depress what?  What about Inhibitory receptors and what do they increase?
Definition

ER-open Na channels and depresses conductance in Cl and K

IR-open Cl channels and increases conductance of K

Term
Characteristics of small molecule, rapidly acting NT
Definition

Effect most acute nervous system responses

Synthesized in cytosol of presynaptic terminals and transported to vesicles

usually increase or decrease ion channel conductance

vesicles are recycled

Ex:E,NE,DA,GAGA,Ach, serotonin

Term
Characterisitics of Nueropeptide, Growth factors-slow acting NT
Definition

cause prolonged actions

ribosomal synthesis in nueronal cell bodies, golgi packaging

axonal streaming transport to terminal

vesicles not recycled

110 times potent as small NT

Term
What is the key to one way transmission?
Definition
AP begins in proximal axon, not postsynaptic membrane
Term
Excitatory PS Potential causes and influx of what? What about IPSP?
Definition

EPSP-influx of Na(deporalization)

IPSP-influx of Cl or efflux of K(hyperpolarization)

Term
What causes presynaptic inhibition?
Definition
GABA-acts on axon upstream from terminus, Cl influx, AP diminishes
Term
What are teh two types or NT release summations and describe?
Definition

1)Spatial-multisynaptic NT release to exceed threshold

2)Temporal-monosynaptic NT release in rapid succession to exceed threshold 

Term
Can dendrites generate an AP?
Definition
No, not enough ion voltage-gated channels. They promotes summation by sending an electrotonic current to the soma.
Term
What does fatigue, pH, Hypoxia. theophylline(caffeine), Strychine, anesthetics do to synaptic transmission?
Definition

FAtigue-reduce AP firing with repetitive stimulation(NT depletion)

pH-Acidic-decreases excitability, Basic-increase excitability

Hypoxia-decreases excitability

Caffeine-reduces excit threshold

Strychnine-inhibits inhibitory NT

Anesthetics-stabilize membranes, increase threshold

Term
What is the labeled line theory?
Definition

sensory receptors transmit only modality(can only distinguish one thing) because these impulses go to 1 part in CNS

Ex. anterolateral system nerves can only preceive pain, where as the dorsal column only senses touch or pressure 

"labeled" for one sensory Fx

Term

Slow adapting receptors are called?

fast?

Definition

slow-tonic

fast-phasic

Term
which summation signals a variation of "parallel" fibers in a single nerve. What about one fiber?
Definition

multi-spatial

one-temporal

Term
what are the two major highways of somatic signals to the brain?
Definition
dorsal column abd anterolateral
Term

 

describe the dorsal column-medial lemniscal system and the anterolateral system.

Definition

DC-ML-crosses in the medulla, large and fast fiber, transmit diverse sensory modalities.

AL-crosses immediately, small slow fibers, transit limited sensoryh modalities

Term
features of area 1 and 2 of the somatosensory cortex.
Definition

1-sensory signals for all contralateral modalities end here, regional organization correspongind to body areas

2-poorly understood, input from area 1 is needed for fx

Term
differences bw fast and slow pain.
Definition
fast-onset les than .1 sec, superficial note generated in deep tissue,
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