College A&P Nervous System

decremental conduction

requires a voltage gated ion, gates all along the axon to open and allow Na+ to diffuse into the axon

saltatory conduction

the rapid, energy-efficient propagation of action potentials (nerve impulses) along myelinated axons, where the signal appears to "leap" between gaps

Role Na+ plays in process of nerve conduction

Na+ makes interior of nerve more positive, when increasing from -70mV to -55mV, it will open and allow Na+ gates to open.

Role potassium plays in the process of nerve conduction

K+ gates will open to repolarize and bring back down to -70mV

the factors that influence the speed of propagation of the nerve impulses

1. more myelin, faster speed

2. large diameter of axons, faster than smaller axons

3. temp: higher = faster propagation

axondentric

axons connects to dendrite of second

axosomatic

axon connects with second axon body cell

axoaxonic

axon connects with second axon

interneuron

neuron positioned between two neurons

electrical junction vs. chemical synapse

electrical junction is found in visceral smooth muscle, cardiac muscle and developing embryos

chemical synapse is two cells connected via gap junction

what is RMP of average neural cell

-70mV

what is threshold voltage of average neural cell

-55mV

3 divisions of peripheral nervous system

1. sympathetic

2. parasympathetic

3. enteric

leakage gated ion

opens and closes on their own

mechanically gated ion

opens and closes due to vibrations or any mechanical stimulus

voltage gated ion

Mv gets to -55 and then opens

ligand gated ion

opens and loses due to chemical stimulus

3 ways neurotransmitters are processed after they have been bound to their receptors

1. diffusion from receptors

2. active uptake back into presynaptic axon

3. degradation by enzymes

medulla oblongata

breathing, swallowing

hypothalymus

controls body temperature

cerebral cortex

conscious thought, memory

cerebellum

coordinates voluntary movement and balance

thalamus

triage center: decides what is important

what is autonomic nervous system?

system regulates involuntary control

what is EPSP and IPSP and how do they relate to the concept of summation

sometimes binding od nt causes post-synaptic neuron to become more negative (IPSP) or more positive (EPSP)

basic function of nervous system

bodys primary command control and communication network

motor vs. sensory nerve

motor: CNS to muscle (causes change)

sensory: external/internal receptors to CNS

Schwann cell

regenerates myelin sheath

oligodendrocytes

can create tumors, make myelin sheath and CNS

microglial

cleaner cells, smaller

astrocyte

blood brain barrier, large and stong

ependymal cells

lines spinals cords central canal

Gray Matter

unmyelinated axons/neural cell bodies

White matter

myelinated axons