Transcript 1-nervous_system

NERVOUS SYSTEM
Major functions of the nervous
system-the 3 C’s
Control
Communicate
Coordinate
Receive stimuli
Process information and decide output
Direct response
Nervous System Anatomy
Central Nervous System
Includes the
brain and spinal
cord
Controls all body
functions
Peripheral Nervous System
(PNS)Includes
cranial nerves
and nerves
from spinal
cord
Nervous system Sensory/Afferent
Sensory: afferent neurons
Receive a stimulus
Can come from organs
(visceral)
Can come from the body
(somatic)
Efferent
Motor (efferent neurons)-response
Voluntary: muscles
Involuntary:
Parasympathetic—maintain
homeostasis
Sympathetic--fight or flight--stress
response
Reflexes
Nerve cell structure (Neuron)
Dendrite--receive impulse
Cell Body--processes impulse
Nucleus--control center of cell body
Mitochondria--powers the cell
Nissl bodies--manufacture protein
Nerve cell structure (Neuron)
Axons--transmits impulse
Schwann cells--conducting cells
Myelin sheath—insulation—speeds up impulse
Nodes of Ranvier--speeds up impulse
Nerve cell structure (Neuron)
Axon terminals—end of axons
Terminal end buds (Synaptic end bulbs) -contain neurotransmitters
Types of Neurons
Interneurons--connecting
neurons
Unipolar--one process
Bipolar--one axon and
one dendrite
Multipolar--branches to
create many dendrites or
axon terminals
Neuroglia cells --supporting cells of the
CNS and PNS
CNS include:
Astrocytes-Blood-brain barrier
Protect brain
Astrocyte
Microglia-CNS supporting cells
Macrophages
Clean up debris and
excess ions
Protect neurons
Oligodendrocyte--CNS
Make myelin for
CNS
Cannot repair if
damaged
Ependymal cells--CNS
Line spinal cord
cavity
Line cranial cavity
Circulate CSF
(cerebrospinal fluid)
PNS NEUROGLIAL CELLS
Schwann Cells –
form myelin sheaths
around axons
Holds neurons in
place
Speeds up
transmission
Can repair if
damaged
Keeps messages
from being
scrambled
Satellite cells--PNS
Surround ganglia
cell bodies
Provide nutrients
and support
Types of Matter
Gray Matter –
non-myelinated
neurons
White Matter –
Myelinated neurons
Meninges
Protective membranes for the brain
Dura mater--tough mother
Arachnoid mater--spider mother--contains
CSF
Pia mater--soft mother
Nerve impulse conduction
Is ion exchange
Nerve impulse conduction
Continuous and Saltatory conduction
Reflex arc
Predictable, automatic response to stimuli
5 parts--Sensory receptor--->sensory neuron--->
integrating center (processing center)---> motor
neuron--->effector (completes action)
Nerve tracts
Bundles of neurons
Many are long tracts
Brain
Cerebrum
Largest
part of
brain
Cerebral cortex
Gray matter of
the brain
Gyruselevations
Sulcusgrooves
Fissure-deep
grooves
Cerebellum
“Little brain”
Coordinates
skeletal muscle
movements
Inferior to
cerebrum
Diencephalon
Epithalamus—
sleep-wake cycle
Thalamus-emotional center
Hypothalamus-connection
between brain and
endocrine system
Regulates vitals
Lobes of the brain
Frontal lobe
Anterior portion
Concentration
Planning
Problem solving
Writing
Speech
Parietal lobe
Sensation of
touch,
pressure, and
pain
Helps us
understand
speech
Helps us use
words to
express
feelings
Temporal lobe
Hearing and
balance
Memory of
visual scenes
and music
Helps us
interpret
sensory
experiences
Occipital lobe
Vision
Helps us
combine vision
with other
sensory
experiences
Brainstem
Functions as a relay
station for nerve
impulses
Midbrain--reflex center
for hearing and vision
Pons--regulates rate and
depth of breathing
Medulla oblongata-controls vitals, plus
coughing, sneezing,
swallowing and vomiting
Cerebrospinal fluid
Watery cushion that protects
the brain and spinal chord
In ventricles of the brain and
arachnoid space of the
meninges