A&P LECTURE 18 TERMINOLOGY

what does the autonomic NS subdivide into

- Sympathetic ANS - Parasympathetic ANS - Enteric NS

afferent vs efferent neurons

- afferent neurons carry sensory information to the CNS -- afferent = approach the CNS - efferent neurons carry motor information from the CNS to a muscle or a gland -- efferent = exit the CNS

multipolar - how many neuronal processes - what do the neuronal processes consist of

- multiple - many dendrites and a single axon

unipolar - how many neuronal processes? - does the axon split? -- if so, what is at each end? - where does the soma sit? - what are the two portions that the axon appears to be divided into?

- one - yes -- to one end is all dendrites -- to the other end is axon that wakes a synaptic connection with a target - alongside the axon -peripheral process and the central process

bipolar neurons - how many neuronal processes -what does each end of the neuronal processes consist of

- two - at one end is dendrites, and the other process includes the axon

central process - what kind of nerve does it belong to ? - what does it carry and where does it carry it to?

- unipolar - carries APs away from the soma to the CNS

peripheral process - what kind of nerve does it belong to - what does it contain - what does it carry and where does it carry that something to? - how long is it normally?

- unipolar - dendrites - and AP from the periphery toward the soma - about a meter in length

what is different about axon injuries in the PNS from the CNS

CNS - no neurolemma - no regrowth occurs

what are the two main divisions of the nervous system

CNS, PNS

what are neurogila

Cells that support and protect neurons

what are the gaps in the myelin sheath called

Nodes of Ranvier

what is the sympathetic ANS a division of and what does it do

PNS --> Motor --> Autonomic - fight or flight

what is your enteric nervous system a division of and what does it relate to

PNS --> Motor --> Autonomic - related to the GI tract

what is the parasympathetic ANS a division of and what does it do

PNS--> Motor --> Autonomic - rest/ digest

what are the two types of neuroglia in the PNS

Schwann cells and satellite cells

what is a glioma

a brain tumor originating from the neurogila

tract

a bundle of axons in the CNS

nerve

a bundle of axons in the PNS

a neuron consists of:

a cell body, and processes (dendrites and axons)

ganglion

a cluster of somas in the PNS

nucleus

a cluster of somas within the CNS

what is the myelin sheath

a miltilayered lipid and protein covering

neuron

a nerve cell

dendrite

a neuronal process that brings information into the cell

axon

a neuronal process that sends information form the cell to a target

where is the gray matter in the brain

a thin layer outside of cortex, and also covering the cerebrum and cerebellum

afferent vs efferent

afferent - carry sensory information from the PNS towards the CNS efferent - carry motor information (from the CNS toward and effector in theRNS) -- the effector being either a muscle or a gland

the axon generates what

an action potential

what are the four types of neuroglia in the nervous system

astrocytes, oligodendrocytes, microglia, and ependymal cells

what kind of nerve would you use for your special senses

bipolar

what are oligodendrocytes

cells that form myelin sheath around axons in the CNS

What is multiple sclerosis?

demyelinating disease

what kind of nerve is a unipolar nerve

general sensory -- touch -- afferent

gray vs white matter

gray - contains unmeylinated parts of the nervous tissue -- somas, dendrites, unmeymlinated axons, axon terminals and neuroglia white - composed of aggregations of myelin processes

Myelinated vs. Unmyelinated

has a myelin sheath vs does not have a myelin sheath

the electrical insulation that the myelin sheath provides to the axon ___ the speed at which the AP travels

increases

nervous system

is responsible for controlling all our behaviors, memories, and movements also helps maintain health and homeostasis

what is demyelination

loss or destruction of the myelin sheath

the soma is the ____ of the neuron. Like the dendrites, it ______ signals from other cells and sends them towards the _____

main nutritional and metabolic region, receives, axon

if your neuron is not unipolar or bipolar then it is

multipolar

what is the most common neuron in your body

multipolar

where is the trigger zone on a unipolar neuron

near the junction of the dendrites and the axons

which are more abundant, neurons or neuroglia

neuroglia

what are the chemicals that are used to bridge the synapse

neurotransmitters

are neuroglia excitable?

no

do the Schwann cells touch each other?

no, this is how the AP "jumps" (is propagated) quickly

what are the two types of neuroglia that produce the myelin sheath

oligodendrocytes and schwan cells

dendrites ___ incoming signals from other cells and ___ them towards the ____

receive, send, axon

the dendrites and the some constitute both the ___ and the ___ regions of the neuron

receptive and integrative

what are the three basic functions of the nervous system

sensation, integration, response

the PNS is divided into __ and __

sensory and motor units

what are your special senses

sight, smell, taste, and hearing

what kind of nerve is a bipolar nerve

special senses -- all but touch -- afferent

he dendrites and somas also ___ and ___ the incoming signals

sum up and integrate

what do neuogila do

support neurons, attach neurons to blood vessels, produce the myelin sheath around axons, carry out phagocytosis

What does the myelin sheath do?

surrounds and electrically insulates the axons

what is the place of communication between a neuron and its target cell?

synapse

what is the autonomic NS a branch of and what does it consist of

the PNS --> Motor - autonomic efferent neurons -- carry motor information form the CNS to involuntary (cardiac and smooth) muscles and glands

What is the somatic NS a branch of and what does it consist of

the PNS --> Motor - somatic efferent neurons -- send information from the CNS to the voluntary (skeletal) muscles

what does the outermost layer of the myelin sheath consist of

the Schwann cell's cytoplasm, and the nucleus

what does electrical excitability mean

the ability to respond to a stimulus and convert it to an AP

if the integrated signals are large enough, where will the outgoing signal be generated

the axon hillock, aka the trigger zone

neurology

the branch of medical science that deals with nervous tissue

soma

the cell body

what are functional classifications of a neuron based on?

the function of the neuron

Where is the gray and white matter in the spinal cord?

the gray is the "gray H" in the white snow

what do the motor components of the PNS consist of and is it afferent or efferent

the motor portion is subdivided into -- somatic NS -- Autonomic NS -efferent

what happens when a neuron in the PNS is injured

the neurolemma forms a regeneration tube which stimulates regrowth of the axon

what are structural classifications of a neuron based on?

the number of processes extending from the soma

what is the neurolemma

the outer nucleated cytoplasmic layer of the Schwann cell which encloses the myelin sheath

where does the axon conduct the action potential to

the target cell

the axon is the ___ or ___ region of the neuron

transmitting , conductive

What kind of neurons are sensory neurons?

unipolar

what kind of nerve is a multipolar nerve

used for motor and inter neurons --efferent

are neurons electrically excitable?

yes

can neuroglia multiply and divide? if so, where?

yes, in mature nervous systems

what do the sensory components of the PNS consist of and is it afferent or efferent

-somatosensory -special sensory -visceral sensations - afferent

what are the three steps of formation of the myelin sheath

1) Schwann cells begin to form myelin sheaths around axons during fetal development 2) each of the Schwann cells wraps itself around 1mm of the axon's length by spiraling many times 3)the hundred wrappings of the Schwann cell's membrane make up the myelin sheath