Transcript supplies the skeletal muscles & skin Autonomic Nervous

NERVOUS SYSTEM
CENTRAL NERVOUS SYSTEM (CNS)
Brain
Spinal Cord
PERIPHERAL NERVOUS SYSTEM
Cranial & Spinal Nerves
Somatic -- supplies the skeletal muscles & skin
Autonomic Nervous System (ANS)
-- supplies smooth muscles, cardiac, & glands
1. Sympathetic Nervous System
2. Parasympathetic Nervous System
NEURON -- structural unit of the nervous system
Dendrites -- conducts impulse towards the cell body
Cell Body
-- contains the nucleus
Axon
-- conducts impulses away
from the cell body
Nervous tissue contain cells called Neuroglial (glial)
-- supply nutrients
-- cleans up debris
-- assist in the production
Cerebrospinal fluid
Schwann Cell
-- type of neuroglial cell found outside
the CNS & forms the Myelin Sheath
a connective tissue that binds nerve
fibers together
Neurilemma Sheath
-- is that part of the Schwann cell that
contains the nucleus & allows for
regeneration of the nerve
The Myelin sheath acts as an insulator
& speeds up nerve transmission
Nodes of Ranvier
-- are bare spots where myelin is not present
-- allows impulse to “jump” from one node
to the next & further increase speed of
transmission
Synapse or Synaptic Cleft
-- junction between the
Axon of one neuron &
the Dendrite of another
TYPES OF NEURONS
SENSORY (AFFERENT)
send impulses to the
brain & spinal cord
MOTOR (EFFERENT)
send impulses away from
the brain & spinal cord
INTERNEURON
found only in the CNS &
can be sensory or motor
--the more complex the required action, the
greater the number of interneurons involved
NEUROTRANSMITTERS
-- are certain chemicals releases from the axon of
one neuron that changes the permeability of
the cell membrane of the receiving neuron to
allow Sodium into the cell
Epinephrine
Norepinephrine
produced by the Adrenal Medulla
Acetylcholine -- released at the neuromuscular
junction
Dopamine -- found only in the brain & helps regulate
body movement & facial expression
Others:
-- Serotonin
-- GABA
-- Histamine
-- Endorphins
-- Prostaglandin
-- Glutamate
SPINAL CORD
-- contains 31 pairs of spinal nerves
-- consists of gray & white matter
1. It is a pathway for conducting
impulses to and from the brain
& spinal cord
2. It is an area of reflex activity
Spinal Tracts are nerve fibers in the cord
-- found in the columns of white
matter
-- Ascending Tracts -- carries
sensory impulses
-- Descending Tracts -- carries
motor impulses
Spinal Roots
-- Each spinal nerve is attached to the cord by
2 roots or horns located in the gray matter
Ventral Root -- carries motor signals
Dorsal Root -- carries sensory signals
-- these roots are combined in the spinal
nerve as it leaves the vertebral column
making all spinal nerves Mixed Nerves
-- Areas where roots combine:
Cervical -- serves muscles & skin of neck & diaphragm
(Phrenic Nerve)
Brachial -- serves muscles & skin of the arms & hands
(Radial Nerve)
Lumbosacral -- serves muscles & skin of lower abdomen,
genitalia, legs & feet (Sciatic Nerve)
CEREBRUM-- contains 2 hemispheres ( right & left)
Frontal
lobe
Corpus
Parietal
lobe
callosum
Temporal
lobe
Lateral
ventricle
Third
ventricle
Occipital
lobe
Midbrain
Thalamus
Hypothalamus
Pituitary
Cerebellum
Pons
Medulla
oblongata
Fourth
ventricle
Thalamus & Hypothalamus together is called the Diencephalon
FUNCTIONS OF THE
HYPOTHALAMUS
1. Body Temperature
2. Some emotions, such as fear & pleasure
3. Control of the Autonomic
Nervous System
Link between
nervous &
4. Control of the Pituitary gland endocrine systems
5. Water balance
6. Appetite
7. Sleep
8. Center for mind over body phenomena
Cerebral Cortex (Cerebrum)
--tissues of the brain are convoluted
Gyri
-- area of brain responsible for consciousness
& functions in intelligence
Major Functions
1. Sensory perception
2. Voluntary control of movement
3. Language
Sulci
4. Personality Traits
5. Sophisticated mental events
a. Thinking
d. Creativity
b. Memory
e. Self-consciousness
c. Decision making
Lobes of the Brain
Frontal Lobe
-- thought association
-- judgement
-- discrimination
-- control of skeletal muscles
-- Broca center located in the left hemisphere
(damage to this area causes APHASIA)
Parietal Lobe
-- sensory area for pain, touch,
& temperature
-- understanding speech & using
speech to express thoughts & feelings
Temporal Lobe
-- sensory area for hearing
& smelling
-- interpreting what we see,
hear, and smell
Occipital Lobe
-- responsible for vision
-- combining visual images
-- These areas when stimulated or depressed will
result in certain expected symptoms
BRAIN STEM
Midbrain
-- connects cerebellum, brain stem,
spinal cord & cerebrum
-- acts as a relay center for
sight, hearing, & feeling
Pons
-- also acts as connection for the cerebrum &
spinal cord
-- helps to regulate breathing along with the Medulla
-- reflex center concerned with head movement
in response to visual & auditory stimuli
Medulla Oblongata
-- is a relay center & contains
many vital functions:
1. Respiratory Center
-- regulates rate, depth, &
rhythm of respiration
-- sensitive to decreased O2, increased
2
CO , & change in pH
2. Cardiac Center
-- regulates rate & force of the heart beat
3. Vasomotor Center
-- contracts or dilates blood vessels to regulate
blood pressure
-- also contains cough, vomiting, & swallowing centers
-- may affect hiccups
-- area where nerve fibers shift
so that right side of brain
control left side of body
& visa versa
-- Reticular Activating System (RAS)
area between the Pons & Medulla
responsible for keeping us awake
CEREBELLUM
-- aids in the co-ordination
of voluntary muscles
-- it integrates impulses
received from the cerebrum
(Frontal Lobe)
-- helps maintain balance by receiving
information from the inner ear
-- aids in muscle tone, so that all muscle fibers
are slightly tensed
CEREBROVASCULAR ACCIDENT (CVA)
-- a disorder of the blood system to the cerebrum
resulting in death of tissue
-- also called a Stroke
-- may be due to a blood clot or broken blood vessel
-- area of dead tissue is called an Infarct
ISCHEMIA
-- a deficiency of blood
to a body part
Transient Ischemic Attack
(TIA)
Central Nervous System is protected by:
1. Skull & vertebrae
2. Meninges
A. Dura Mater
-- thickest & toughest
layer
-- contains sinuses to
collect venous blood
B. Arachnoid membrane
-- middle web-like covering
-- cerebrospinal fluid flows
in the web-like spaces
C. Pia Mater
-- thin delicate layer that follows the contour
of the brain & spinal cord
Cerebrospinal Fluid
-- occupies the spaces between the middle layer
of the meninges
-- it cushions & nourishes
the brain & spinal cord
-- it is obtained from the
circulatory system
-- it is formed by the Choroid
Plexuses (capillaries in the
walls of the ventricles)
Pathway: Lateral ventricle
Third ventricle
Fourth ventricle
Foramen of Munro
Aqueduct of Sylvius
into the subarachnoid space
around the brain & spinal cord & returned to
the circulatory system
CRANIAL NERVES
On Old Olympus, Towering Tops, A Fin Visiting
Germany Viewed Some Hops
I. Olfactory
Smell
Sensory
II. Optic
Sight
Sensory
III. Oculomotor Controls eye muscles
IV. Trochlear
V. Trigeminal
Supplies one eye muscle
Motor
Motor
Deals with pain, touch, &
Both
temperature of the face
Supplies muscles for chewing
VI. Abducen
Supplies one eye muscle
Motor
VII. Facial
Deals with facial expression
taste, salivary & lacrimal
glands
Both
VIII. Vestibulocochlear Hearing & balance Sensory
IX. Glossopharyngeal Supplies tongue,
Both
parotid gland, &
muscles for swallowing
X. Vagus
Supplies thoracic &
abdominal organs
and digestive glands
-- when stimulated
can drop the heart rate
Both
XI. Spinal Accessory Supplies muscles
of neck & back
Motor
XII. Hypoglossal Allows for tongue
movement
Motor
AUTONOMIC NERVOUS SYSTEM (ANS)
-- part of the Peripheral Nervous System
-- supplies smooth muscles, cardiac muscles, & glands
-- functions to maintain homeostasis and is
concerned with involuntary functions
Sympathetic
Parasympathetic
--begins in
-- begins in the
the thoracic
cranial area
region &
& in the
extends to
lower
the 2nd
sacral area
lumbar
spinal
nerve
Function of the Sympathetic &
Parasympathetic Nervous Systems
-- Sympathetic nervous system stimulates while
the Parasympathetic inhibits the activity
of a given organ
-- acceleration
versus
slowing down
-- sympathetic system is involved with energy
expenditure
-- parasympathetic system is concerned with
restorative process
FUNCTIONS OF THE AUTONOMIC NERVOUS SYSTEM
SYMPATHETIC RESPONSE
ORGAN
Increase rate
HEART
Decrease rate (to normal)
BRONCHIOLES
(Smooth muscle)
Constrict (to normal)
Dilate
Pupils dilate
PARASYMPATHETIC RESPONSE
IRIS
Pupils constrict (to normal)
Decrease secretion
SALIVARY GLANDS
Decrease peristalsis
STOMACH & INTESTINES
(Smooth muscle)
Increase peristalsis for
normal digestion
Decrease secretion
STOMACH & INTESTINES
(Glands)
Increase secretion for
normal digestion
Contracts to prevent
defecation
INTERNAL ANAL
SPHINCTER
Relaxes to prevent
urination
URINARY BLADDER
Increase secretion (to
normal)
Relaxes to permit defecation
Contracts for normal
urination
Fight or Flight Syndrome
-- what happens to our body when under stress;
whether frightened or angry
-- increases heart rate, respiratory rate,
dilates pupils & inhibits digestive
& urinary tract
-- Most organs receive both Sympathetic &
Parasympathetic stimulation
-- Like the gas pedal and a brake on a car