Transcript Nervous System Anatomy

Main Function:
This communication
system controls and
coordinates functions
throughout the body and
responds to internal and
external stimuli.
Our nervous system
allows us to feel pain.
nervous system
Consists of:
Sensory division
and Motor
division
-includes all
sensory neurons,
motor neurons,
and sense organs
Consists of: brain, spinal cord, nerves and
sense organs
Sense Organs: Eyes, Skin, Ears, Nose & Tongue
A nerve is an organ
containing a bundle
of nerve cells called
neurons.
Neurons carry
electrical messages
called impulses
throughout the
body.
Picture shows hundreds of
severed neuron axons
dendrite
Axon
cell body
cell
body
TYPICAL MOTOR
NEURON
synapse
muscle
tissue
Because neurons never touch, chemical
signalers called neurotransmitters must
travel through the space called synapse
between two neurons.
Neurotransmitters (pink
spheres)
Synapse (gap)
The message
is transferred
when
RECEPTORS
receive
neurotransmitters.
Parts of a Neuron
1. Cell body: contains nucleus & most of the
cytoplasm
2. Dendrites: projections that bring impulses into
the neuron to the cell body.
3. Axon: long projection that carries impulses away
from cell body
1
2
3
Sensory
Neuron
Interneuron
Synapse
Synapse
Motor
Neuron
Interneuron
Synapse
Motor
Neuron
Sensory
Neuron
Muscle
Contracts
Sensory
Neuron
carry impulses from
sense organs to
spinal cord & brain
Fun Fact:
Where can the
largest cells in the
world be found?
The giraffe’s sensory and
motor neurons! Some
must bring impulses from
the bottom of their legs
to their spinal cord
several meters away!!
Interneuron
-processes impulses
in brain and spinal
cord
- connect sensory and
motor neurons
Motor Neurons
carry impulses from the
brain & spinal cord to
muscles & glands
Axon End
Axons branching out
to muscle fibers
• Nerves work together with muscles for
movement. An impulse begins when one
neuron is stimulated by another neuron or
by the sense organs.
• The impulse travels down the axons of
Sensory neurons to the brain cells called
Interneurons.
• The brain will then send an impulse
through motor neurons to the necessary
muscle or organs, telling it to contract.
A reflex is an
involuntary
response that is
processed in the
spinal cord not
the brain.
Reflexes protect
the body before
the brain knows
what is going on.
Reflex Arc
Consists of: Brain and Spinal Cord
Cerebrum
brain
Cerebellum
Medulla Oblongata
Spinal Cord
The Brain
• weighs 1300 - 1400 g
• made up of about 100
billion neurons
• “the most complex
living structure on the
universe” Society for
Neuroscience
• makes us who we are
Brain structure
Cerebrum
cerebellum
hypothalamus
Pituitary gland
medulla
brain functions
Cerebrum
(forebrain)
Largest part of the brain,
surface is greatly folded;
divided into right and left
hemispheres
Voluntary or conscious
activities of the bodylearning, judgment
Cerebellum
(hindbrain)
10% of brain volume; 5%
of brain’s neurons
Coordinates and balances
the actions of the muscles
(develop as a child)
Medulla
Oblongata
(Brain Stem)
attached to the spinal
cord at the base of the
brain; contains gray
matter that receives
signals from the spinal
cord
Controls involuntary
actions like blood pressure
(vasometer centre), heart
rate (cardiac centre),
breathing (respiratory
centre), and swallowing
Parts of the Cerebrum
alcohol and the brain
Parts of the cerebrum
memory game
Divisions of the Cerebrum
• frontal lobe: motor areas (control muscles),
integration of info (think, reason and plan
action)
• parietal lobe: received sensory info from
the skin and skeletal muscles; sense of taste
• occipital lobe: receives info from the eyes
• temporal lobe: receive info from eyes
Forebrain Structures
• Thalamus
• Hypothalamus
• Pituitary gland
Thalamus
contains paired masses of gray matter that are
arranged into bodies called nuclei and act as a relay
station – receives sensation of touch, pain, heat and
cold and info from the muscles
HYPOTHALAMUS
Controls physiological equilibrium of the
body via nerve impulses acting a main
control center for the autonomic nervous
system and endocrine system
The master gland – attached to the hypothalamus and under
its control
Made up of two glands – posterior (back) lobe that releases
ADH and oxytocin and the anterior (front) lobe
Produces hormones that control many of the endocrine
glands
Located in the
brainstem; the pons
contains bundles of
axons travelling
between the
cerebellum and the
rest of the CNS
(bridge)
Functions with the
medulla in regulation of
breathing and has
reflex centres involved
in head movement
MIDBRAIN
• short segment of the brainstem between the
cerebrum and pons
• contains fibers that transmit sensory
impulses from the spinal cord to the
thalamus and motor impulses from the
cerebral cortex back to the spinal cord
• also involved with sight and hearing
ventricles
• cavities within the brain that produce and
store cerebrospinal fluid (cushions the
brain)
• include lateral, third and fourth
The cerebral cortex is the thin outer layer of the brain (covers
cerebrum) often referred to as gray matter (billions of cells).
Enables us to experience sensation, voluntary movement and all
thought processes associated with consciousness.
Layer of white matter that joins the
two cerebral hemispheres and carries
signals between
Animations
• http://www.youtube.com/watch?v=Li5nMs
Xg1Lk
• http://www.g2conline.org/?gclid=CNP54O
G0_J0CFZho5QodXFRpqg