Download Nervous System - Belle Vernon Area School District

Nervous System
Functions
1.
2.
3.
4.
5.
I. Division of the Nervous
System
A. Central Nervous System
(CNS)
1.
2.
B. Peripheral Nervous
System( PNS)
1. Nervous that are
outside the CNS
a.
b.
2. Sub divisions of the PNS
a.
(afferent)-conducts action potential from
sensory receptors to the CNS.
b.
(efferent) – conducts action potential from
CNS to PNS. (muscle or glands)
a.
- serves sensory nerves,
receptors (skin) sensory organs (head) & motor
nerves that stimulate the skeletal muscle voluntary nervous system
b.
- automatic
1.
- involving
stressful activities
2.
- normal
functioning
II. Nerve Tissue
A.
- support &
maintain neurons
1.
- Provide
insulation covering around
large axons.
2.
neurons
- Anchor
to blood capillaries.
3.
- form &
circulate cerebrospinal fluid.
4.
- phagocytize
invading microorganisms.
5.
- insulation
covering around the CNS.
B.
- functional unit of the nervous
system
1. Structure
a.
- receive impulses
b.
- typical to other cells
1.
- similar to RER
2.
threads
- network of fine
c.
(nerve fiber) - carries impulse
away from the cell body.
1. One axon to every neuron
2.
– side branches
3.
– site of the axon
missing Nissl bodies
d.
insulating barrier from a
schwann cell around a axon.
1. Nourishment
e.
cytoplasm & nuclei of the
schwann cell on the outer
covering.
f.
- gaps where
myelin sheaths are absent.
g.
gray matter
h.
white matter
-
2. Types of Neurons
a.
- many dendrites (signal to muscles).
b.
- 1 dendrtie & axon (eyes, ears, & nose).
c.
d. Sensory (afferent)
CNS.
e. Association (interneurons)
the CNS.
f. Motor (efferent)
CNS.
3. Function
a.
potential Polarized mv
sodium ions
the neuron than
.
potassium ions
the neuron than
.
-this is maintained by the
.
-but
due to
the large
ions stuck inside.
b.
potential – (excitable) Nerve impulse +
mv
– sodium moves into the cell
– potassium moves outside the cell.

C.
period - hyperpolarized
mv. Inside is more
.
Review
Where do you find the following ions in
relations to the neuron?
chloride, sodium, potassium
Why do they call it a sodiumpotassium pump?
What is a threshold signal?
4. All or None Response
a.
- minimum strength
that can cause an
action potential.
b.
cannot initiate a
response.
-
c.
- series
of subthreshold stimuli
can have a cumulative
effect.
5. Transmission of impulse
a. Synapse
b. Presynaptic
c. Postsynaptic
d. Synaptic end bulb
e. Synaptic vesicles
f. Neurotransmitters (50
different)
6. Excitatory vs. Inhibitory
transmissions
a. Excitatory causes a
(more
Na allowed to enter the
postsynaptic)
b. Inhibitory
III. The Central Nervous
System
A.
- Conduction
pathway for impulses
between the brain & the
PNS, reflex center.
Protected by
.
Compose of
matter.
Conduction pathway
between the brain &
nerves.
Reflex center
long.
cm
B. Protective coverings membrane layers.
1.
- outermost,
thick, & tough.
- space
filled with fat between
the bone & dura
matter.
2.
- middle layer
of collagen fibers.
Subarachnoid space
filled with
Cerebrospinal fluid
(CSF) - shocking
absorning &
transporting.
3.
- inner
most, attached to the
spinal cord.
C. Structures
1.
segments each with a
pair of spinal nerves.
2.
- center
of the cord (looks like an H).
a.
terminal endings of
sensory neurons.
b.
- motor
neurons of the
autonomic nervous
system.
c.
- motor
neurons to skeletal
muscle.
3.
- Surrounds the
gray matter
a. Anterior Columns b. Lateral Columnsc. Posterior Columns -
D. Conduction Pathways
1.
- sensory info to the brain.
2.
- motor info from the brain.
neurons to the effectors.
E. Spinal nerves
1. Mixed nerves because they contain both sensory
and motor neurons.
2. Organizied into regions that they emerge.
C–
T–
L–
S–
Co –
3. Plexus – nerves come together and separate.
a. three main ones
cervical c1-c4
brachial – c5-t1
lumbosacral – l1-s4
E. Reflex Center
1. Reflex is an
way of responding to an
emergency situation.
a.
at the end of
the sensory neuron.
b.
neuron to the
CNS Associated neuron in
the spinal cord (reflex
center).
c. Motor
2. Types of reflexes
a.
- actions involve
skeletal muscles.
1. Withdrawal – protective
2. Pattellar - knee jerk (2
neurons, sensory to the
motor)
3. Stretch reflex
b.
- smooth &
cardiac to maintain
homeostasis.
1. Breathing,
vomiting,
sneezing, &
coughing
IV Brain - integrative center of the
nervous system
billion neurons.
One of the largest internal organs.
A. Protective coverings - Meninges membrane layers.
1.
thick, & tough.
- outermost,
- space filled
with fat between the bone &
dura matter.
2.
- middle layer of
collagen fibers.
Subarachnoid space filled with
Cerebrospinal fluid (CSF) shocking absorbing &
transporting.
3.
- inner most,
attached to the spinal cord
B. Cerebrum “
Largest structure in the brain
”-
1. Cerebral hemispheres
2. Convolutions
- upwards folds
- inward folds
3. Fissures
4. Four lobes
a.
– smell,
motivation, aggression,
mood.
b.
– touch, pain,
temperature, balance, taste
c.
– sight
d.
– smell,
hearing, memory
5. Sensory Functions
a. small portion of the sensory
input results in sensation.
b.
– sends signals to the brain.
-each tract is limited ex…
ex. Lateral spinothalamic
tract
pain & temperature.
ex. Dorsal column
touch, position,
pressure
-most tracts have 2 or 3
neurons to the brain.
-almost all end in the
thalamus.
C.
– between brain stem & cerebrum
1.
- relay station for sensory impulses (except
smell) entering the brain.
2.
– pineal body (puberty)
2.
- Primary control for the autonomic
nervous system (homeostasis).
a. Thermostat control for body
temp
b. regulates food & water uptake
c. maintain walking & sleeping patterns.
d. associated with emotion (rage,
aggression, sex drives
1. Pituitary glands - endocrine glands
D.
- reflexes for rapid eye, head & trunk movements
E.
- Bridges the cerebrum & cerebellum
F.
- part of the brain stem & most inferior brain
structures
1. Cardiac & respiratory center
G.
- sends signals to the skeletal muscles
Cranial Nerves
Cranial Nerves
V. Disorders
A.
– inflammation of the brain
B.
– inflammation of the meninges.
C.
– viral disease transmitted by saliva of a animal
bite.
D.
– bacterial disease that produces a neurotoxin
that affect lower motor neurons in the spinal cord & brain
stem.
E.
– autoimmune disorder caused by a viral
infection
F.
– general, defects in motor functions from
several types of brain damage or birth related injury.
G.
– muscular rigidity, lack of movement
H.
I.
– mental deterioration (dementia).
J.
– group of brain disorders that cause
seizures
K.
- shingles
VI. Effects of Aging
A. Natural decline in functioning neurons, including sensory neurons.
(balance loss, coordination, blood pressure, bladder)
B. By the age of 60 up to 50% loss of lower motor neurons in lumbar
region.
(loss of muscle mass & increase fatigue)
C. Size and weight of the brain decreases, but other neurons can
compensate for this loss.
D. Short term (problem solving, thinking) memory decreases slowly
until the age of 60. Afterwards increase rate of memory loss,
especially after 70.
E. Long term memory seems to be unaffected.
F. More time to fall asleep, more walking periods during the night,
and longer amount of time being awake at night.
G. Many older people shoe no change and some show a 10%
increase in thinking ability due to education, health, motivation.