INTRO TO NERVOUS SYSTM, SYNAPSES, SUMMATION AND SPINAL CORD

PNS =

peripheral nervous system

CNS=

central nervous system

Voltage

measure of potential energy genertaed between two points

more charge difference = ____ voltage 

higher

insulators have ___ resistance

high

conductors have ___ resistance

low

resistance is the

hinderance of charge flow from one place to another

Leakage (Non gated channels) are ____ open

Always

gated channels ____

open and close

chemically (liagand) gated channels open when

a specific chemical binds

volage gated channels open

in response to change in membrane potential

mechanically gated channels open

in response to physical deformation of receptors

Ions want to be at the ___ energy state

lowest

What are the characteristics of the neuroglia in the CNS and PNS?

The oligodendrocytes and Schwann cells perform similar functions in different parts of the nervous system

Neuron RMP is

~ -70mV

Astrocytes are found in the ____ nervous system

Central

Microglial cells are found in the ___Nervous System

Central

Ependymal Cells are found in the ___ Nervous system

Central

Oligodendrocytes are found in the ___ nervous system 

Central

Satellite Cells are found in the ___ nervous system

Peripheral

Schwann Cells are found in the ___ nervous system

Peripheral

Neuroglia are found in the ___ nervous system

central and peripheral

What are the two divisions of the motor (efferent) division of the CNS?

Somatic Nervous System and the Autonomic nervous system

What is the function of myelin sheaths?

insulates axons and incresses speed of impulse transmission

____ form myelin sheaths in the PNS

Schwann Cells

____ form myelin sheaths in the CNS

Oligodendrocytes

the ECF has higher ___ than the ICF

NA+

ICF has higher ___ than the ECF

K+

Graded potentials are caused by

incoming signals causing local changes

Action Potentials are caused by

long distance signals of axons

Depolarization is …

a decrease in potential (toward zero and above)

Hyperpolarization is …

an increase in membrane potential (away from zero)

Depolarization ____ but ____ quickly

Spreads, Decays

An Action Potential is a

Signal of communication for neurons

Synapses are

junctions that mediate the transfer of information from one neuron to another cell

What are the two types of synaptic neurons?

Presynatic and postsynaptic neurons

What are the two main methods of synaptic communication?

Chemical and Electrical

What type of synapse is most common?

chemical

The chemical synaptic cleft prevents ___

direct transfer of information to ensure unidirectional communication

The higher impulse frequency the more ___ of vesicles

exocytosis

What is summation?

The addition of both EPSPS and IPSPS

EPSP stands for

Excitory Postsynaptic potential

IPSP stands for

Inhibitory postsynaptic potential

An EPSP is...

a temporary change in a neuron's membrane potential that makes it more likely to fire an action potential

AN IPSP is

a change in a neuron's membrane potential that makes it less likely to fire an action potential

What factors contribute to the effect of neurotransmitters?

The type of neurotransmitter, its concentration, and the type of receptor

Which structures are mixed nerves vs motor or sensory only nerve fibers?

Dorsal roots contain sensory nerves while ventral roots contain motor nerves

What parts of the spinal cord horn are responsible for efferent and afferent conduction?

The dorsal horn is responsible for sensory information

The membranes and organization of the nerve fibers is very similar to what tissue?

Skeletal muscle

What are the two types of summation?

Temporal and Spatial

Temporal Summation

One or more presynaptic neurons transmit impulses w/ varying frequency

Spatial Summation

Postsynaptic neuron stimulated by large number of terminals simultaneously

True or False: Temporal and Spatial Summation can happen at the same time

True

Neurotransmitters are classified by

Chemical Structure and Function

Acetylcholine is released at the ___

neuromuscular junction

Inhibitory or excitatory: Acetylcholine

Both

Inhibitory or excitatory: Dopamine

Both

Inhibitory or excitatory: Norepinepherine

Excitatory

Inhibitory or excitatory: GABA

Inhibitory

The effects of neurotransmitters are determined by ___

The receptor to which it binds

Cauda Equina (Horse Tail)

Nerve roots extending inferiorly

Filum Terminale

Thin thread of fibrous tissue at the end of the conus medullaris, attaches to coccygeal ligament

The spine beings at the ____ and ends at the ____

Foramen Magnum of the skull, L1-L2 Spine (Conus Medullaris)

WhWhat are the three spinal meninges?

Pia Mater, Dura Marer and Arachnoid Mater

Posterior Root contains

Axons of sensory neurons

Anterior Root contains

Axons of motor neurons

Dorsal root ganglia contains

cell bodies of sensory neurons

Endoneurium 

loose connective tissue around axons and myelin sheaths

Perineurium

Coarse connective tissue around fibers into fascicles

Epineurium

Tough fibrous sheath around all fascicles to form nerve

there are ____ pairs of mixed nerves in the spine

31

Ventral roots

Motor fibers that innervate skeletal muscle 

Dorsal Roots

Sensory fibers from dorsal root ganglia that conduct impulses from receptors

What are the three banches of the spinal nerves?

Dorsal Ramus, Ventral Ramus, Meningeal Branch

Dorsal Ramus

Small Branch of the spinal nerves that innervates the posterior body trunk

Ventral Ramus

Large branch of spinal nerves that innervates the body trunk and limbs

Meningeal Branch

Branch of spinal nerves that innervate the meninges and blood vessels

True or False?: Rami can carry both sensory and motor signals

True

True or False?: Roots can carry both sensory and motor signals

False

Dermatomes

overlapping areas of Skin innervated by cutaneous branches of single spinal nerve