1. The Nervous System
Part II-The Brain

2. I. Central Nervous System: The Brain
Cerebrum
Largest part
Sensory & motor functions
Higher mental functions (memory, reasoning, etc)
Brainstem
Connects the cerebrum to the spinal cord
Cerebellum
Coordinates voluntary muscle movements
Diencephalon
Processes sensory info

3. A. The Cerebrum Divided into right and left cerebral hemispheres
Covered by folds called convolutions and grooves called sulci (little groves) and fissures (big grooves)
Connected by the corpus callosum
It has a cortex: an outer covering about 2 mm thick
Gray matter vs. white matter
The cerebral cortex is divided into LOBES which control various functions

5. 1. Frontal Lobe (Brain 1 handout)
Control of voluntary muscles in the body
Motor speech (Broca’s area)
Voluntary eye movement
Concentration, planning, problem solving
Rational thought, intelligence

6. 5. Primary Motor Area (frontal)
2. Parietal Lobe
Somatosensory area- touch, taste and other sensory info
understanding speech, using words (Wernicke’s)
3. Temporal Lobe
smell and hearing
interpretation of sensory experiences
4. Occipital Lobe
visual senses
5. Primary Motor Area (frontal)
movement of skeletal muscles

7. 6. Pre-Motor Area (frontal)
learned motor skills
7. Motor Speech Area (Broca’s) (frontal)
controls mouth movement for speech
8. Somatosensory Area (parietal)
conscious awareness of sensations
interpretation of sensory experiences
9. Auditory area (temporal)
Hearing is processed
10. Visual Area (occipital)
Processes input from optic nerves

8. Cerebral Hemispheres Hemisphere = half of sphere (brain)
The right side of the brain controls the left side of the body and vice versa
Hemispheres connected by the Corpus callosum

9. B. The Cerebellum
Processes sensory information about limbs, joints, and other body parts to determine desired positions.
Balance, coordination of skeletal muscle, posture

10. C. Brainstem Brainstem: Connects the cerebrum to the spinal cord
Midbrain: visual and auditory reflex center
Pons: transfers nerve impulses from cerebrum to cerebellum
Medulla Oblongata: controls heart and breathing rates, controls blood pressure, vessel changes

11. D. Diencephalon
Thalamus-Receives all sensory impulses and relays them to the appropriate region of the cerebral cortex
Produces awareness of sensation
Hypothalamus –Links the nervous system to the endocrine system
Regulates heart rate, blood pressure, body temp, hunger, gland secretions, sleep etc.
Maintains homeostasis-links nervous to endocrine system

12. The limbic system is a collection of structures involved in emotional behavior and your feelings
Includes the thalamus, hypothalamus, amygdala and hippocampus (long term memory)
Fear, anger, pleasure, sorrow
Olfaction travels through the limbic system so scent is related to feelings.

13. II. Neurotransmitters Excitatory neurotransmitters
1. Increase postsynaptic membrane permeability to Na+
2. Threshold is reached for message to be sent
B. Inhibitory neurotransmitters
1. Decrease permeability to Na+
2. Decreases chance nerve impulse will occur.

14. Types of Neurotransmitters

15. Pathways: Brain uses Neurotransmitters
The Brain Reward Pathway
Beyond Reward

16. A. Acetylcholine (ACH) First neurotransmitter discovered (1921)
Excitatory
Used for skeletal muscle contraction at neuromuscular junctions & synapses between the brain and spinal cord
Message causes muscles to contract or continues impulses
Nicotine inactivates ACH receptors and causes brain to create more receptors

17. B. Serotonin
Found in the brain, released by regions in the brainstem but effect entire brain.
Sleep, mood, pain and temperature regulation
Antidepressants (Prozac, Zoloft, Paxil, etc) work by allowing serotonin to accumulate in the synapse,
“SSRI’s” or Selective Serotonin Reuptake Inhibitors
feel more content
LSD mimics serotonin, and MDMA (aka: ecstasy) releases excess serotonin

18. C. Dopamine AKA “the brain reward”
Regulates emotions, moods and subconscious control of skeletal muscle
Cocaine
interferes with the process by which dopamine is taken back up (leaves more in the synapse)
Methamphetamine
excess dopamine release

19. Dopamine - cont’d
Dopamine also sends signals that help coordinate your skeletal muscle movements
Parkinson’s Disease
deficient dopamine production
tremors

20. D. Endorphins Flood the synaptic cleft during pain or stress
Usually inhibit neurons from firing, causing an analgesic effect
At lower levels can excite the next neuron
Reduces pain and makes one feel good
“Opiates” (heroin, codeine, morphine, oxycodone, hydrocodone, etc)
bind to endorphin receptors and mimic endorphins

21. E. Anandamide
Involved in working memory, regulation of feeding behavior, generation of motivation and pleasure
Anandamide receptors are called cannabinoid receptors
A lot of cannabinoid receptors in the hippocampus (short term memory), cerebellum (coordination) and basal ganglia (unconcious muscle movement) of brain
THC (found in marijuana) mimics anandamides and binds to cannabinoid receptors