Divisions of The
Nervous System
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Bases of
Comparison
Sympathetic
Neurons
Parasympathetic
Neurons
Effect
Active body function
“fight or flight”
Normal activity
“rest and digest”
Neurotransmitter
Noradrenalin
Acetylcholine
Restoring enzyme
Monoamine oxidase
Acetylcholinesterase
SAME
SAME
Function automatically Function automatically
(involuntary)
(involuntary)
Serve all internal
organs
Serve all internal
organs
Fight or Flight
Adrenal Glands
Sudden simultaneous release of noradrenalin from
all the sympathetic neurons (as in times of fright)
has a critical effect.
It causes the release of the hormone adrenalin from the
interior of the adrenal glands located on top of the
kidneys.
The noradrenalin and the adrenalin initiate and sustain
what is known as the ‘Fight or Flight” response.
They prepare the body to respond to danger in the
following ways:
1. Increase heart rate so that more blood is supplied
to the body more quickly.
2. Widen air passageways so that more air can be
exchanged with each breath.
3. Sudden contraction of some muscles to
tense the body up for action. Included in this
is the contraction of the diaphragm. A
scared person will gasp, inhaling suddenly.
4. The iris of the eye contracts thus widening the
pupil to maximize visual alertness.
5. Increased blood flow to the skeletal muscles so
they are more able to act.
6. Decreased digestive activity, circulation and
control.
If you need help to label/colour your brain …
Try this …
http://www.youtube.com/watch?v=fPIcQ640EoE
ALSO!! Seriously … SERIOUSLY, you should have
worked your way through the simulations now.
Especially the ‘outreach harvard’, ‘whfreeman’,
‘phet.colorado’ and ‘mcgraw-hill’ links at a
MINIMUM!!
They are fast, educational, interesting, cool, and even
fun. No way that you can’t enjoy Mouse Party!
Brain:
Medulla Oblongata
-Brain Stem (bottom of the brain)
-Pathway between brain and spinal cord
-Controls: Vomiting, coughing, sneezing,
hiccoughing, swallowing.
-Controls: Heartbeat rate, breathing, and
blood pressure.
Cerebellum
-Butterfly shaped
-Rear, lower portion of the brain
-Second largest portion of the brain
-Controls: Muscle co-ordination (smooth
graceful motions) muscle tone, balance and
posture.
Hypothalamus
-Located just above the pituitary gland.
-Controls: The pituitary gland and production of
hormones
Hunger, thirst, sleep, body temp, water
balance, and BP.
Maintains homeostasis by controlling endocrine
system
Thalamus
-Above the hypothalamus
-Controls: Relay station for information going
to the cerebrum.
Channels info to appropriate place and
prevents sensory overload.
Cerebrum
-Largest part of the brain
-Controls: Conscious thought
Perceives sensory information
Initiates movements
-Contains 2 hemispheres (Right and left)
-Memory
Parts:
1.
2.
3.
4.
Frontal Lobe- Conscious thought
Parietal Lobe – Temperature, Touch and Pain
Temporal Lobe – Hearing and smelling
Occipital Lobe – Vision
Corpus Callosum
-Holds the hemispheres of the
Cerebrum together
-Conducts impulses from one side of
the brain to the other.
• Quick Review Questions
C
D
B
A
B
B
D
D
Hypothalamus would NOT make ADH (antidiuretic hormone) and would
NOT send it to the posterior pituitary gland. ADH would NOT be released
which would cause the collecting duct in the nephron in the kidneys to be
relatively impermeable to water. The urine would be more dilute and less
water would be taken back into the body.
What makes humans distinctive in animal
world?
• Is it the size of brain?
• Not really … (elephant and whales are larger)
• Has to do with the size, increase in the folds of the
cortex and the cortex’s ratio of the brain’s total
weight. (i.e. In shrews, the cortex accounts for 20%
of the brain's weight, and in humans, it accounts for
80%!)
• The increased folds, enable a larger cortical surface
area to fit inside the cranial vault, allow for a better
organization of complex behaviours.