Transcript The Nervous System

•Protected by bone:
skull and vertebrae
*not protected by bone
Controls VOLUNTARY body
movements, through the action of
skeletal muscles. Interacts with
surroundings using senses
Maintains INVOLUNTARY actions
such as heart rate, digestion,
sweating, sexual arousal
Vigorous activity.
Ex: “Fight or Flight” response
Non-emergency activity.
Ex: “Rest and Digest”
Examples:
Sympathetic
Structure
Parasympathetic
Rate increased
Heart
Rate decreased
Force increased
Heart
Force decreased
Bronchial muscle relaxed
Lungs
Bronchial muscle
contracted
Pupil dilation
Eye
Pupil constricted
Food motility reduced
Intestine
Digestion increased
Sphincter closed
Bladder
Sphincter relaxed
Decreased urine
secretion
Kidneys
Increase urine secretion
Sympathetic Responses
Dominance by the sympathetic system is
caused by physical or emotional stress
-- “E situations”
– emergency
- embarrassment
- excitement
- exercise
• Alarm reaction = flight or fight response
– dilation of pupils
– increase of heart rate, force of
contraction & BP
– decrease in blood flow to
nonessential organs
– increase in blood flow to skeletal
& cardiac muscle
– airways dilate & respiratory rate
increases
– blood glucose level increase
Parasympathetic Responses
• Enhance “rest-and-digest”
activities
• Mechanisms that help conserve
and restore body energy during
times of rest
• Normally dominate over
sympathetic impulses
• SLUDD type responses =
salivation, lacrimation, urination,
digestion & defecation and 3
“decreases”--- decreased HR,
diameter of airways and diameter
of pupil
• Paradoxical fear when there is
no escape route or no way to win
– causes massive activation of
parasympathetic division
– loss of control over urination and
defecation
Neuron: nerve cell
dendrites
Cell body
(soma)
axon
Myelin sheath
(yellow padding)
axon
Node of Ranvier
(gap)
Axon
terminals
Multiple Sclerosis
Dendrite
Axon
Soma
“Afferent” : Ascending
Sensory neuron receives
information from the
senses (environment)
and sends it to the CNS
“Efferent”: Descending
A motor neuron receives
information from the CNS
and sends it to a muscle or
gland.
Stimulus (fire)
Optic: eye
Auditory: ear
Olfactory: smell
Taste: taste buds
Touch: skin receptors
Muscle
gland
Response (pull away)
2 Additional neurons
1. Interneuron
– Found in the CNS only.
– They associate or “connect” sensory neurons
and motor neurons.
2. Mirror Neurons
• allow humans to “mimic” each other
• possibly allow us to learn speech, signal
meaning to one another, and to feel empathy
•New field of study (1990s)
Mirror neurons are found all over the brain
and they look just like other neurons.
What makes them special is the web of
connections that link these neurons in the
motor and sensory systems to the limbic
centers that process visceral and
emotional reactions.
While they may be in
place at birth, they are
vastly expanded through
experience. A baby
smiles…her mother smiles
back…the brain sets up a
circuit.
Evidence for mirror neurons:
When a researcher would pick up raisins or
sunflower seeds, neurons that a macaque would
use when engaged in the same task would fire.
In humans, the same neurons fired when subjects
felt a glove brush their leg and when they watched a
video of an actor’s leg being brushed by a glove.
The thought of a loved one’s hand receiving an
electric shock lights up many of the same brain
areas as shocks that are directly experienced.
Can even indicate strength of emotion…
The same mirror neurons fired when the subjects saw a
hand reaching for both of these, BUT…
Neurons fired strongly
neurons fired more weakly
The Neurons that Shaped Civilization
Lecture on Mirror Neurons (7min)
http://www.ted.com/talks/vs_ramachandran_the_neurons_that_shape
d_civilization.html
PBS; Mirror Neurons (15 min)
Synapse
• Point of communication between
two nerve cells.
• Three parts:
• presynaptic membrane
• synaptic cleft (gap)
• postsynaptic membrane
neurotransmitter
• A __________________is
the chemical
that is exchanged at the synapse. This
allows the chemical message to
be______________________________
Passed from one neuron to the next
Click for animation
Action Potential
http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter14/a
nimation__the_nerve_impulse.html
Synapse
http://highered.mcgrawhill.com/sites/0072495855/student_view0/chapter14
/animation__chemical_synapse__quiz_2_.html
http://www.youtube.com/watch?v=90cj4NX87Yk&fe
ature=related
Questions
•
•
The brain and spinal cord make up the _______________________
Which of the following do not belong in this grouping
–
Autonomic – sympathetic – parasympathetic – central nervous system
•
•
•
•
•
•
•
Stimuli from the environment are received by _______________
The insulating sheath of the axon is composed of ________________
Impulses that go to the brain are? Ascending or Descending
The gaps between the myelin in a neuron are called? ________________
The gaps that exist between two neurons are called _____________________
The part of the neuron where the nucleus is found is the __________________
What is “fight or flight”?
•
What part of the nervous system would be responsible for flight or flight?
•
Explain what else happens to your body during this response.
•
Why might yawning be contagious?
Nervous System
Central Nervous
System
Peripheral Nervous
System
Somatic
Autonomic
Sympathetic
Parasympathetic
Brain Plasticity
(video clip)
Nerve Proliferation and Pruning: “use it or
lose it” in the brain.
Babies have about 15,000 connections per
neuron while adults have about a third less
(10,000).
The brain undergoes two major
developmental phases, one in the womb and
the second during the childhood/teen years.
Links that are used are reinforced and
strengthened while the ones that aren’t used
are “pruned” or die off.
Spinal Nerves:
31 pairs of nerves leave the
spinal cord and carry
impulses to and from the rest
of the body (except for the
head which is served by the
cranial nerves).
•8 pairs of cervical
•12 pairs of thoracic
•5 pairs of lumbar
•5 pairs of sacral
•1 pair of coccygeal
Spinal Cord Injuries
Nervous System Animations
CranialNerves
Number
Name
Function
I
Olfactory Nerve
Smell
II
Optic Nerve
Vision
III
Oculomotor Nerve
Eye movement; Pupil dilation
IV
Trochlear Nerve
Eye movement
V
Trigeminal Nerve
Somatosensory information (touch, pain) from the face and head; muscles for chewing.
VI
Abducens Nerve
Eye Movement
VII
Facial Nerve
Taste (anterior 2/3 of tongue);Somatosensory information from ear;Controls muscles used
in facial expression.
VIII
Vestibulocochlear Nerve
Hearing; Balance
IX
Glossopharyngeal Nerve
Taste (posterior 1/3 of tongue);Somatosensory information from tongue, tonsil, pharynx;
Controls somemuscles used in swallowing.
X
Vagus Nerve
Sensory, motor and autonomic functions ofviscera (glands, digestion, heart rate)
XI
Spinal Accessory Nerve
Controls muscles used in headmovement.
XII
Hypoglossal Nerve
Controls muscles of tongue
* Largest part of the brain
• Cerebrum (cerebral cortex)
• Thalamus
• Pituitary
Also:
Limbic System
• Limbic System
• Hypothalamus (regulates
homeostasis…hunger, thirst, temp,
sexual behavior, fighting, activity level)
• Hippocampus (build new memories)
• Amygdala (emotional responses)
• fear, anger, aggression, sexual
desire
Consists of:
•Cerebellum
• Pons
• Medulla oblongata
Parietal Lobe
Frontal Lobe
Occipital Lobe
Temporal Lobe
Cerebellum
Brainstem
* There are two hemispheres in the brain: Left and Right.
RIGHT
Which one is shown in this diagram? __________________
Left Hemisphere
controls RIGHT side
of the body
Right Hemisphere
controls LEFT side of
the body
Frontal Lobe:
Functions:
• How we know what we are doing within our environment (Consciousness).
• How we initiate activity in response to our environment = reasoning / thinking
• Controls our impulsive responses.
• Controls our expressive language.
• Controls motor functions.
• Involves word associations.
• Memory for habits and motor activities.
Frontal Lobe
Observed Problems:
• Loss of simple movement of various body parts (Paralysis).
• Inability to plan a sequence of complex movements.
• Loss of spontaneity in interacting with others.
• Loss of flexibility in thinking.
• Persistence of a single thought (Perseveration).
• Inability to focus on task (Attending).
• Mood changes (Emotionally Labile).
• Changes in social behavior.
• Changes in personality.
• Difficulty with problem solving.
• Inability to express language (Broca's Aphasia).
Parietal Lobe
Function
•Location for visual attention.
•Location for touch perception.
•Goal directed voluntary movements. Manipulation of
objects.
•Integration of different senses that allows for
understanding a single concept.
Observed Problems:
•Inability to attend to more than one object at a time.
•Inability to name an object.
•Inability to locate the words for writing.
•Problems with reading (Alexia).
•Difficulty with drawing objects. Difficulty in distinguishing
left from right.
•Difficulty with doing mathematics (Dyscalculia).
•Lack of awareness of certain body parts and/or
surrounding space (Apraxia) that leads to difficulties in
self-care.
•Inability to focus visual attention. .
Parietal Lobe
Occipital Lobe:
Location: Most posterior lobe, at the back of the head.
Functions:
• Vision
• Color recognition
Occipital Lobe
Observed Problems:
• Defects in vision (Visual Field Cuts).
• Difficulty with locating objects in environment.
• Difficulty with identifying colors (Color Agnosia).
• Visual illusions - inaccurately seeing objects.
• Word blindness - inability to recognize words.
• Difficulty in recognizing drawn objects.
• Inability to recognize the movement of an object
(Movement Agnosia).
• Difficulties with reading and writing
Temporal Lobe:
Location: Side of head above ears.
Functions:
•Hearing ability
•Memory acquisition
•Some visual perceptions
•Categorization of objects.
Temporal lobe
Observed Problems:
•Difficulty in recognizing faces
•Difficulty in understanding spoken words (Wernicke's Aphasia).
•Disturbance with selective attention to what we see and hear.
•Difficulty with identification of, and verbalization about objects.
•Short-term memory loss.
•Interference with long-term memory
•Increased or decreased interest in sexual behavior.
•Inability to categorize objects.
•Right lobe damage can cause persistent talking.
•Increased aggressive behavior
Motor functions
Cognition
Problem solving
Information
processing
Planning
Reasoning
Pain/touch
sensation
Judgment
Spatial orientation
Impulse
Speech
memory
Visual perception
Vision
Emotional response
Color recognition Hearing
Memory
Speech
Broca’s area
Wernicke’s Area
“Language output”.
Responsible for spoken
language. People with
damage to this area have
trouble creating words and
sentences.
“Language input”.
Responsible for language
comprehension. People
with damage to this area can
speak, but it is incoherent.
•Motor speech.
•Sensory speech
* These parts are found in the left hemisphere only!!
Motor Speech
Sensory speech
Cerebellum:
Location: at the base of the skull
Functions:
•Coordination of voluntary movement
•Balance and equilibrium
•Some memory for reflex motor acts.
Observed Problems:
•Loss of ability to coordinate fine
movements.
•Loss of ability to walk.
•Inability to reach out and grab objects.
• Tremors.
•Dizziness (Vertigo).
•Slurred Speech (Scanning Speech).
•Inability to make rapid movements
cerebellum
Brain Stem:
Location: Deep in Brain, leads to spinal cord.
Brain Stem
Functions:
•Breathing
•Heart Rate
•Swallowing
•Reflexes to seeing and hearing (Startle Response).
•Controls sweating, blood pressure, digestion, temperature
Observed Problems:
•Decreased vital capacity in breathing,
•important for speech.
•Swallowing food and water (Dysphagia).
•Difficulty with organization/perception of the environment.
• reflex control
Major Parts:
Midbrain
Pons
Medulla Oblongata
midbrain
pons
Medulla oblongata
Brain Parts
Cerebral Cortex
Cerebellum
Brainstem
Brain Glands
Thalamus
Hypothalamus
Pituitary
Thalamus:
Location: found in the center of the brain
Function:
•Translates sensory information and
relays it to the cerebral cortex.
•Responsible for levels of awareness,
such as sleep.
•Maintains consciousness
Observable Problems:
•Damage can lead to permanent coma
•If sensory information is not
transported to the cerebral cortex, you
will not respond to the external stimuli.
thalamus
Hypothalamus:
Hypothalamus
Function:
•The hypothalamus is like your brain's inner
thermostat
•The hypothalamus knows what temperature
your body should be (about 98.6° Fahrenheit
or 37° Celsius).
•If your body is too hot, the hypothalamus
tells it to sweat.
•If you're too cold, the hypothalamus gets you
shivering.
•Both shivering and sweating are attempts to
get your body's temperature back where it
needs to be.
PITUITARY GLAND: (“master gland”)
Pituitary Gland
•The pituitary gland is very small — only about
the size of a pea!
•Its job is to produce and release hormones into
your body. (Growth Hormone).
•This gland is a big player in puberty, ultimately
producing sperm in males and eggs in females
• This little gland also plays a role with lots of
other hormones, like ones that control the
amount of sugars and water in your body. And it
helps keep your metabolism going. Maintains
homeostasis.
• The pituitary controls other glands…therfore
called the “Master Gland”.
With each heartbeat,
arteries carry about 20 to 25
percent of your blood to your
brain, where billions of cells
use about 20 percent of the
oxygen and fuel your blood
carries.
When you are thinking hard,
your brain may use up to 50
percent of the fuel and
oxygen.
Carotid artery
Skull bone
Meninges
brain
Cause: Inflammation of the meninges. Can be caused by a
virus or bacteria and can be extremely harmful and
contagious.
Symptoms:
stiff neck, sore back, light irritation, nausea,
body aches, sleepy, confused, fever
sensations
sight
smell
sound
Motor
movement
Generate thoughts,
problem solve,
make plans
Form and store
memories
The positron emission
tomography (PET) scan on
the left shows typical patterns
of brain activity associated
Reading
with:
thinking
Hearing
speaking
Kluver-Bucy Syndrome
• Caused by damage to the temporal lobe and amygdala.
• Inability to recognize familiar objects.
• Lack of fear of objects such as snakes, spiders, fire, and other
commonly feared objects
• Inappropriate or unnatural oral fixations
• Inappropriate sexual behavior, such as public masturbation
Deterioration of brain cells.
Observable shrinkage, shriveling,
cell death and tissue loss.
Cerebral cortex
shrivels up. Affects
thinking, planning,
and memory
Hippocampus is
destroyed.
Responsible for new
memories
Early Alzheimer’s
Thinking and
planning
Learning and
memory
Late Alzheimer’s
•Deterioration of cell in a portion of the
brain called Substantia Nigra (“black
substance).
•No longer release the neurotransmitter
Dopamine.
•Responsible for control of
movement and balance and is
essential to the proper functioning
of the central nervous system
•Leads to slowed and/or
uncontrolled movements, tremors,
and rigidity.
The convolutions of the brain are made
up of “ridges and grooves”
Grey matter: dark areas around the
outside of the cerebral cortex. The dark
color is the soma of the neurons found
here.
Cross section of the cerebral cortex
White matter is the “lighter” inner layer of the
brain section. This is composed of the axon
part of the neuron and it is responsible for
connecting to the billions of other neurons in
the brain.
What’s it’s function? _________________________________
Longitudinal fissure:
Long groove that
separates the left and
right hemispheres in the
brain
Gyrus: “Ridges” that lie
between the grooves in
the brain
Sulcus: “Grooves” in the
brain
Together the gyrus and sulcus make up
the “folded” pattern you see in the brain.
This patterns are called convolutions of
the brain.
1. _________________
5. _______________
9. _______________
2. _________________
6. _____________ (lobe) 10. ______________
3. _________________
7. _____________ (lobe) 11. ______________
4. _________________
8. _____________ (lobe) 12. ______________
Cross section