Test 4 nervous system Flashcards
The nervous system uses…
and it occurs in three steps…
…The nervous system uses cells called neurons to send messages from cell to cell, by chemical or electrical means
. the three steps are
Sensory input
Integration
Motor output
the nervous system is …
the master controlling and communicating system of the body
Sensory input is…
touch, pain, temp, vibration..
these travel from body to central nervous system
Integration is…
processing the information and will determine the correct response
Motor output
produces and responds
What are the two divisions of the nervous system
CNS Central nervous system-brain and spinal cord, sensory input
PNS Peripheral Nervous system-NERVES AND GANGLIA, motor output
What is a nerve
a bundle of nerve fibers(axons) wrapped in fibrous connective tissue
what is ganglion
a knot-like swelling in a nerve where neuron cell bodies of PNS are concentrated
CNS central nervous system contains…
brain and spinal cord. in center. understands the action
PNS peripheral nervous system contains…
arms, fingers, toes, chest, abdomen,
also contains spinal nerves to and from spinal cord and cranial nerves to and from brain
What does the sensory division do
sensory division(afferent) carries signals from receptors to CNS
There are two divisions
1. somatic
2. visceral
Somatic sensory division carries what…
signals from receptors in the skin, muscles, bones, and joints ex. touch, pain, temp, vibration
Visceral sensory division carries what…
carries signals from the viscera( heart, lungs, stomach, and urinary bladder ex.pain, filling of organs, bloating , distension, nausea
Motor(efferent) division carries signals from CNA to effectors which are…
glands and muscles that carry out the body’s response
4 kinds
Somatic
visceral
sympathetic
parasympathetic
What does somatic motor division do?
Somatic motor division(efferent)
carries signals to skeletal muscles.;causes voluntary muscle contraction and automatic reflexes
What does visceral motor division do
the visceral motor division ANS(autonomic nervous system) carries signals to glands, cardiac and smooth muscle;no voluntary control. called visceral reflexes
What does the sympathetic division of ANS do?
stimulates and prepares the body for action
What does the parasympathetic division of ANS do?
has a calming effect on the body
neurons are…
excitable, conductive and they secrete
What are the three functional classifications of neurons?
Sensory (afferent neurons which detect stimulus and transmit info to CNS
Motor neurons(efferent) sends signals out to muscles and glands.ie. flinching, flexing, producing saliva
Interneurons (inbetween) connect sensory neurons to motor neurons-our decision makers
Which matter has no myelin
Gray matter
Which matter has myelin
White matter
multipolar neuron is
most common type , the most neurons in CNS-one axon and multiple dendrites
unipolar neurons
or pseudo are found in PNS-single process leading away from cell body;splits into peripheral process and central process
Where are organelles contained
the cell body
Most numerous neurites, resembling branching of a tree; primary sites for receiving signals from other neurons
(can be one or thousands of them)
dendrites
Long, cylindrical extension, relatively unbranched but may give off ____collaterals; specialized for rapid conduction of nerve signals
Axon(nerve fiber)
Axon has its own membrane called…
axolemma
a neuron never has more than one …
Some neurons have..
axon
none
a neuron structure originates at…. mound on one side of cell body
axon hillock
a neuron structure ends in a_____ which forms a synapse with the next cell
bulbous axon terminal
bundle of axons in the CNS
tracts
bundle of axons in the PNS
nerves
many dendrites but no axon. found in brain, retina and adrenal gland
anaxonic neuron
Two- way passage of materials along an axon
Axonal transport:
Anterograde (move away from cell body)transport and
Retrograde transport(move toward cell body)
If there is movement away from the cell body, down the axon, driven by motor protein kinesin( materials made to be transported such as enzymes and ion channels) it is …
Anterograde Transport
If there is movement toward the cell body, driven by motor protein dynein
(materials for disposal)
Retrograde Transport
Non-neural supportive cells of the central nervous system are…
Glial cells
Glial cells are mature neurons and cannot divide which is called …
amitotic
most common glial cell… star shaped, maintain neuron environment, form the blood brain barrier
Astrocyte
form myelin sheath in CNS
oligodendrocytes
line brain cavities and secrete spinal fluid (CSF)
Ependymal cells
Immune cells-engulf debris, perform phagocytosis
Microglia
glia cells that form myelin sheath of the PNS
Schwann cells
(Neurolemmocytes)
surround nerve cell bodies of ganglia in PNS; provide insulation and regulate chemical environment
Satellite cells
mature neurons have little or no capacity for mitosis and seldom form ….
brain tumors
brain tumors arise from protective membranes of CNS called…
meninges
brain tumors arise from:
Meninges
Metastasis from other non-neural tumors in other parts of the body
Glial cells that are mitotically active through life
tumors of glial cells, grow rapidly and are highly malignant… called…
gliomas
Blood brain barrier decreases effectiveness of…
chemotherapy for tumors…
Radiation or surgery are main treatments for brain tumor
Most common types of brain tumors
More commonly in men, any age
Symptoms:
nausea, vomiting, headache, weakness, loss of balance, hearing seizures, paralysis
Astrocytomas
spiral layers of insulation around an axon
myelin sheath
formed by Schwann cells in PNS
and Oligodendrocytes in CNS
Production of myelin sheath is called…
myelination
when does the myelin sheath begin? and be completed?
During fetal development
proceeds rapidly in infancy and is complete by late adolescence
the myelin sheath consists of the plasma membranes of these cells…
20% protein
80% lipid
The speed at which a nerve signal travels down an axon depends on two factors…
Diameter-larger axons have more surface area and conduct more rapidly
Presence or absence of myelin-myelin speeds conduction
disabling disease of the brain and spinal cord.
Immune system attachs myelin sheath of CNS neurons
:numbness, weakness, electric shock sensations…etc
Multiple Sclerosis
auto-immune condition where the myelin sheath of the PNS is destroyed by the body
includes pain or sensation, muscle weakness
starts distally and moves proximally
Life threatening if respiratory muscles are affected
Guillain Barre Syndrome
Charge difference across a plasma membrane
typically 70 millivolts(mV) in and unstimulated “resting” neuron.
this is called…
Resting membrane potential
In RMP, negative value indicates..
more negatively charged particles on inside of membrane, compared to outside
neurons are excitable cells meaning…
they can change their resting membrane potential
Ions are unequally distributed between Extracellular and Intracellular fluid. The RMP results from the combined effect of …
- Diffusion of ions down their concentration gradient through membrane
- Selective permeability of the membrane-some pass more easily
3.Electrical attraction of cations and anions to each other
When gated channels are open, ions diffuse quickly. When it’s along chemical gradients…
it goes from high concentration to low concentration
When gated channels are open, ions diffuse quickly.
when it’s along electrical gradients…
it goes to the opposite charge
flow of ions creates an electrical current and voltage across
membrane. It’s called..
Electrochemical gradient
What structures are located in the axon terminal?
vesicles, neurotransmitters, and Ca2+
