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
|
|
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, |
|
|
