human miterm review

CNS is made up of

brain and spinal cord

Peripheral Nervous System is made up of:

sensory receptors(afferent)motor receptors(efferent) - somatic and autonomic

somatic nervous system

voluntary - sense receptors to CNS

Autonomic Nervous System

involuntary movements using smooth muscle tissue(Enteric

Enteric NS

Controls the gastrointestinal systemsensory stretchesmotor contracts

parasympathetic

rest and digest

sympathetic

fight or flight

What are 3 functions of the NS

Integrativesensorymotor

Integrative nervous system

analyzes and stores data

decides which stimuli are important

sensory nervous system

senses changes in the internal and external environment

motor nervous system

carries instructions from the brain down to the body tissues

Name the parts of a neuron

Axon - conduct impulsescell body - contains organellesdendrites - receive inputsynapse - neural connection siteneurofibrils - forms cytoskeleton

All of the above

a) works with the endocrine system to maintain homeostasisb) communicates with the body via action potentials (nerve impulses)c) is responsible for perceptions and behaviorsd) initiates voluntary movementse) all of these are correct

sensory neurons (afferent)

neurons that carry incoming info from the sensory receptors to the brain and spinal cord

motor neurons (efferent)

neurons that carry outgoing information from the brain and spinal cord to the muscles and glands

Interneurons (association neurons)

found in neural pathways in the CNS

Neuroglia

supporting cells of nervous tissue

no electrical excitability

list 4 types of neuroglia in the CNS

1. Astrocytes - support2. oligodendrocytes - form myelin sheath3. Microglial cells - phagocytosisependymal - produce cerebrospinal fluid

List 2 types of neuroglia in the PNS

1. Schwann Cells - form myelin sheath2. Satellite Cells - structural support

myelin sheath

fatty tissue layer that insulates the axon and increases the speed of nerve impulses

gaps are called Node of Ranvier/ neurofibril nodes

White matter

myelinated axons

the autonomic nervous system is part of the:

PNS

Grey matter

neural cell bodies and short

ganglia

clusters of cell bodies in the PNS

nerves

bundles of axons in the PNS

nucleus

collection of cell bodies in the CNS

Tracts

bundles of axons in the CNS

Graded potential

Communicates over a short distance

Action potentials

communication over long distances or short ones

what are 4 types of ion channels

1. leak channels2. ligand-gated channels3. mechanically-gated channels4. voltage-gated channels

leak channels

randomly open and close

ligand-gated channels

open in the presence of a neurotransmitter/chemical

mechanically gated channels

opens by mechanical vibration or touch

voltage gated channels

open and close in response to changes in membrane action potential

What is the resting membrane potential?

-70mV

more negative charge inside the cell

name the factors affecting the resting membrane potential:

1. unequal distribution of ions2. anions cannot leave the cell3. Na/K pump moves Na out as compensation

Graded potential cont.

shift in membrane potential (hyper/depolarized)

in dendrites and cell body

result from mechanically gated or ligand-gated channels

summation cannot occur

Summation

added graded potentials

Depolarizing phase

flips charge

Na+ opens and moves in -55mv to +30

repolarizing phase

recovery to resting potential

open k channels and close Na+ Channels

k moves out

hyperpolarizing phase

the membrane potential inside is temporarily more negative than the resting level

threshold

the level of stimulation required to trigger an action potential

Sub-threshold stimulus

a stimulus too small to create an action potential in a neuron

suprathreshold stimulus

generates an action potential and often more than one action potential

all-or-none principle

the law that the neuron either fires at 100% or not at all

absolute refractory period

another impulse cannot be generated at all

relative refractory period

can only be triggered by suprathreshold stimulus

action potentials cont.

in voltage-gated channels for Na/K and consists of depolarizing and repolarizing phase

summation cannot occur

propagation of the action potential

the transmission of an action potential down an axon

keeps strength

continuous conduction

step by step depolarization of the plasma membrane (slower)

saltatory conduction

nerve impulse in which impulse jumps from node to node (faster)

Factors Affecting propagation

1. diameter - larger conduct impulses faster2. myelinated fibers - conduct impulses faster than unmyelinated3. nerve fibers - conduct impulses faster when warmed

presynaptic neuron

neuron that sends the signal

What is a synapse

the junction between neurons that permits information transfer

what are postsynaptic neuron/effector cells and what are the 2 types

receives many signals at once1. excitatory PSN - depolarizing (closer to threshold)2. Inhibitory PSN - hyperpolarizing

what is an electrical synapse?

ions spread through gap junctions and allow fast communication

What is an chemical synapse?

Production and release of neurotransmitters

cause either excitatory or inhibitory graded potential

iontropic receptors

bind to ion channels (ex. GABBA)

metabolic receptors

G-protein coupled receptors

does not bind directly and needs 2 channels (Ach binds to receptor

another receptor can open)

What 3 ways can neurotransmitters be removed?

1. diffusion2. enzymatic degradation3. uptake into cells

what is summation of postsynaptic potentials? what are 2 types?

when several presynaptic bulbs release a neurotransmitter at the same time and generate a nerve impulse1. spatial summation - multiple presynaptic neurons flood neurotransmitters2. temporal summation - one presynaptic neuron fires rapidly

The dendrites of a neuron:a) are the main receiving region of a neuronb) secrete neurotransmittersc) conduct impulses toward another neurond) do not carry potentials

only axons do

neurotransmitters can be...

excitatory or inhibitory

Name the small-molecule neurotransmitters

1. ACh - excitatory or inhibitory2. amino acids - glutamate/aspartate are excit. and GABA and glycine are inhib.
* everything else excitatory*3. biogenic amine - norepinephrine

describe the repair of nervous tissue

the nervous system exhibits plasticity

can change with learningPNS - can be repaired if the cell body is intactCNS - little to no repair

functions of the spinal cord

1. process reflexes2. integrate EPSPs and IPSPs3. conduct sensory impulses to the brain and motor impulses to effectors

What protects the spinal cord?

1. vertebrae (bone)2. meninges (CT)3. cerebrospinal fluid

what are 3 parts of the meninges from most superficial to deep?

1. dura mater2. arachnoid mater3. pia mater

dura mater

thick

made of irregular CT

arachnoid mater

middle layer

thin and avascular

loosely arranged collagen and elastic fibers

subdural space

space between dura mater and arachnoid mater

contains fluid

Pia mater

thin

highly vascularized

subarachnoid space

between arachnoid mater and pia mater contains cerebrospinal fluid

Cervical enlargement

lumbar/lumbosacral enlargement

where nerves that supply the lower limbs enter and exit the cord

gray matter of spinal cord

nerve cell bodies arranged in a butterfly shape with anterior and posterior "horns" (anterior is motor

white matter of spinal cord

This area surrounds the gray matter. It is composed of both myelinated and unmyelinated axons. contains white funiculi

central canal

in the center of the gray commissure and contains cerebrospinal fluid

cauda equina

collection of spinal nerves below the end of the spinal cord

anterior median fissure and posterior median sulcus

penetrate the white matter and divide into right and left sides