Please enable JavaScript.
Coggle requires JavaScript to display documents.
Nervous System
Maria Chuc Garcia
P.1, image, Generating an Action…
-
-
Generating an Action Potential
1. Resting state: All gated Na+ & K+ channels are closed
2. Depolarization: Na+ channels open
3. Repolarization: Na+ channels are inactivating, K+ channels open
4. Hyperpolarization: Some K+ channels remain open, & K+ channels RESET
Propagation of an Action Potential
- Allows AP to transmit from origin down entire axon length toward terminals
- Once initiated, AP is self-propagating
- Na+ channels closer to AP origin are inactivate, NO new AP generated
Threshold & the ALL-or-NONE phenomenon
- NOT all depolarization events produce APs
- For axon to "fire", depolarization must reach threshold voltage to trigger AP
-ALL OR NONE= AP happens completely or doesn't happen
ANS vs. Somatic N.S
- Efffectors
ANS- Cardiac muscle, smooth, gland
SNS- Skeletal Muscle
- Efferent Pathways and Ganglia
SNS- Single, thick myelinated group, axon extend in spinal/cranial nerves directly yo SKELETAL muscle
ANS- pathways uses two-neuron chain;
- preganglionic Neuron- Cell body in CNS, light myelinated, preganglionic axon extended to ganglion
- Postganglionic Neuron- cell body synapse with preganglionic axon in autonomic ganglion with nonmyelinated postganglionic axon
- There are 31 pairs of spinal nerves
- All are mixed nerves named from pint of issue to spinal cord
- Supply all EXCEPT head and part of neck
- Every spinal nerve connected to spinal cord VIA 2 roots
Ventral Roots
Dorsal Roots
- Ventral and dorsal branched ROOTLESS
- Acetylcholine(ACh), First identified and best understood, released at neuromuscualr junction
- Biogenic Amines
- Catecholamines: Dopamine, norepinephrine (NE), & epinephrine
- Indolamine: serotonin, made from amino acid
Histamine: made from histidine
- Amino Acids: Make up all proteins; difficult to prove which ones's are neurotransmitters.
- Purines; Monomers of nucleic acids that have effect in CONS and PNS
- Facial: Fibers from pons travele through internal acustic and enlarge
8. Vestibulocochlear: Afferent Fibers from hearing receptors. Mostly sensory function, small motor component
- Glossopharyngal: Fibers from medulla have skull viajuglar. Motor function; inneravate part of tongue.
- Vagus: Only cranial nerves that extend beyond head and neck region.
- Accessory Nerves: Formed from ventral rootless. Rootlkess pass into cranion to each foreman magnum
12. Hyoglossal: Fibers from medulla exit still via hypeglossal canal
- Protected by bone, meninga s , CSF
-Epidural Space; Fat & network of veins in between vertebrae and & spinal dura mater
- Spinal C. terminates in cone-shaped structure ( conus medullaris)
- Brain Stem( Midbrain, Pons, Medulla); Control automotic behaviors for survival. Has white nuclei in white matter
- Cerebellum- Imput from c0rtex, brain stem, and sensory receptors provide coordinated mov. of skeletal muscle. THINKING, LANGAUGE, & EMOTION. Balance and COORDINATION
- Motor
- Carry Impulses from CNS to effectors
-Multipolar
- Cell bodies located in CNS( expect some autonomic neurons)
- Interneurons
-Called Association Neurons
- Life between motor and sensory neurons
- Shuttle signals through CNS pathways
Neuroglia
- 4 main support CNS Neurons
- Astrocytes, microglial cells, ependymal ells, and oligodendrocytes
- Satellite cells surround neuron cell bodies
