1. The Nervous System

2. Functions of the Nervous System
1. Communication and coordination
Adapt and respond to changes from both inside and outside the body
2. Site of reasoning- your brain
3. Two main divisions
Central nervous system (CNS): brain and spinal cord
Peripheral nervous system- the nerves

3. Neuron- basic structural unit of the nervous system
Dendrites- carry impulses towards the cell
Axon-carry impulses away from the cell
Myelin sheath
Synaptic terminal
Epinephrine
Norepinephrine
Acetylcholine

4. Nerves are made of many nerve cells
Afferent/Sensory-sensory nerves carry message to brain
Efferent-motor neurons carry message from brain to muscle
Associate- do both and connect the afferent and efferent neurons once they are in the brain
Heads up

6. Central nervous system

7. Cerebrum-largest part of brain
Cerebrum-largest part of brain. Responsible for reasoning, thought, memory, speech, sensation, etc.
Divided into two halves/hemispheres
Further divided into lobes; occipital, parietal, temporal and frontal

8. Cerebellum-responsible for muscle coordination
Brain stem- most basic functions; respiration, swallowing, blood pressure. Lower part (medulla oblongata) is continuous with spinal cord

9. General Brain Functions
Thalamus
Hypothalamus
General Brain Functions
Brain Waves
Sleep
Memory/Thought

10. Memory Memory Short term memory Long term memory
persistence of learning over time via the storage and retrieval of information
Short term memory
activated memory that holds a few items briefly
look up a phone number, then quickly dial before the information is forgotten
Long term memory
the relatively permanent and limitless storehouse of the memory system

11. Encoding
Encoding
Effortful
Automatic

12. Encoding
Forgetting as encoding failure
Which penny is the real thing?

13. HOMES- Huron, Ontario, Michigan, Erie, Superior
Chunking
use of acronyms
HOMES- Huron, Ontario, Michigan, Erie, Superior
ARITHMETIC- A Rat In Tom’s House Might Eat Tom’s Ice Cream
organizing items into familiar, manageable units
*5 seconds

14. often occurs automatically
like horizontal organization
often occurs automatically

15. Both the brain and spinal cord are covered by a membrane system called the meninges
Spinal cord- begins at foramen magnum and ends at second lumbar vertebrae
Contains both afferent (to the brain) and efferent (motor neurons- away from the brain)

16. Peripheral nervous system Sensory and Motor Divisions
Somatic system
12 pairs cranial nerves
31 pairs spinal nerves
Autonomic
Sympathetic
Fight or flight
Parasympathetic

17. Senses Vision -Structures light travels through= Hearing and Balance
Outer
Middle
Inner
Smell
Taste
Touch and Related Senses

18. The Eye and Vision Vision is the dominant sense in humans
70% of sensory receptors in humans are in the eyes
40% of the cerebral cortex is involved in processing visual information
The eye (or eyeball) is the visual organ
Diameter 2.5 cm (1 inch)
Only anterior 1/6 visible
Lies in bony orbit
Surrounded by a protective cushion of fat

19. some pictures…

20. Cataract (opaque lens)

21. The eye is an optical device: predominantly the lens
(to a lesser degree, not shown here, the cornea also)
Note: images are upside down and reversed from left to right, like a camera
Resting eye set for distance vision: parallel light focused on retina
Resting eye doesn’t see near objects because divergent rays are focused behind retina
Lens accommodates (becomes rounder) so as to bend divergent rays more sharply, thereby allowing convergence on the retina

22. Photoreceptor neurons signal bipolar cells, which signal ganglion cells to generate (or not) action potentials: axons run on internal surface to optic nerve which runs to brain
*Know that axons from the retina form the optic nerve, CN II

23. Photoreceptors: 2 types
Rod cells
More sensitive to light - vision permitted in dim light but only gray and fuzzy
Only black and white and not sharp
Cone cells
High acuity in bright light
Color vision
3 sub-types: blue, red and green light cones
*Know that rods are for B & W and cones are for color

24. One of the Ishihara charts for color blindness
Commonly X-linked recessive: 8% males and 0.4% females

26. The Ear Parts of the ear Outer (external) ear
Middle ear (ossicles) for hearing)
Inner ear (labyrinth) for hearing & equilibrium

27. Skeletal muscles of middle ear
When loud, muscles contract, limiting vibration and dampening the noise

28. Inner ear = bony “labyrinth” of 3 parts
Cochlea - hearing
Vestibule - equilibrium
Semicircular canals - equilibrium
In petrous part of the temporal bone
Semicircular canals____
Filled with perilymph and endolymph
fluids
Vestibule___________
Cochlea_______________________

29. Smell (olfaction) Olfactory epithelium in roof of nasal cavity
Has millions of bipolar neurons = olfactory receptor cells
Only neurons undergoing replacement throughout adult life

31. TASTE Taste buds: mostly on tongue Two types
Fungiform papillae (small, on entire surface of tongue)
Circumvallate papillae (inverted “V” near back of tongue)

32. Types of taste
Sweet
Sour
Salty
Bitter
Glutamate (MSG)
Gustatory (taste) pathway to brainstem & cerebral cortex via two cranial nerves:
VII (Facial n.) – anterior 2/3 of tongue
IX (Glossopharyngeal n.) – posterior 1/3 tongue and pharynx

33. Disorders of the nervous system
Meningitis- inflammation of the linings of the brain and spinal cord
Encephalitis- inflammation of the brain
Epilepsy-seizure disorder. Excessive discharge from neurons. 1 in 200 suffer. Grand mal or petit mal seizures
Cerebral palsy- disturbance in voluntary muscular action
Parkinson’s –decreased neurotransmitter
MS multiple sclerosis- autoimmune where the myelin is stripped.