1. Nervous System

2. Nervous System Brain Central Nervous System Spinal Cord Sensory Nerves
Peripheral Nervous System
Somatic
Motor Nerves
Automatic

3. Function of the nervous system:
Controls and coordinates functions throughout the body

4. The Neuron – nerve cell Dendrite – reception of nerve impulses
nucleus
Axon terminals
Dendrite – reception of nerve impulses
from other cells
Cell body – contains the cell nucleus
Axon – carries the nerve impulse away
from the cell body
Myelin sheath – insulating membrane
Cell body
Myelin sheath
nodes
axon
dendrites

5. Nerve Impulse
Moves like the flow of electrons through a wire

6. Nerve Impulse
2 Phases:
resting potential – the neuron membrane is positive outside and negative inside; the sodium-potassium pump moves sodium out while bringing in potassium
action potential – negative outside and positive inside; as the nerve impulse moves along the neuron from the dendrites through the cell body to the axon, polarity changes across neuron membrane;

8. Practice A
Label the indicated parts. B C

9. Synapse location where nerve impulse moves from one neuron to the next
Tiny gap where the nerve impulse is transferred by chemical neurotransmitters

10. Divisions of the nervous system
Central nervous system (CNS) – brain & spinal cord
Peripheral nervous system (PNS) – nerves to other parts of the body
Sensory – provides brain with information from the senses
Motor – carries information from the CNS to the muscles & glands, divided into somatic nervous system (voluntary movement) and automatic nervous system (involuntary movement)

11. The Brain Controls and coordinate body activities
Meninges – tough covering over the brain & spinal cord
Cerebrum (gray matter) – controls voluntary activities, intelligence
Cerebellum – back of skull; coordinates & balances actions of muscles & body

12. The Brain Brainstem – pons and medulla oblongata
regulates the flow of information between the brain & body
controls blood pressure, heart rate, breathing, & swallowing

13. The Brain
Thalamus – receives messages from the senses & sends them to cerebrum
Hypothalamus –
control center that detects and analyzes hunger, thirst, fatigue, anger, & body temperature
controls and coordinates nervous & endocrine systems

14. cerebrum
cerebellum
pons
Medulla oblongata
thalamus
hypothalamus
midbrain

15. Practice
Which part of my brain…?

16. Reflex Arc
Quick automatic response to stimulation like blinking or sneezing
Nerve impulse goes to the spinal cord & back to muscles without passing through the brain

17. The Senses
Eye – light passes though the cornea, pupil (opening at the front of the eye) & lens to the retina.
Retina – consists of rods (sensitive to light) & cones (distinguishes color)
Optic nerve – sends messages from the retina to the brain

18. Vitreous humor
Muscle
Lens
Fovea
Aqueous humor
Cornea
Optic nerve
Pupil
Iris
Blood vessels
Ligaments
Retina
Choroid
Sclera

19. Ear Has 3 tiny bones - hammer, anvil, stirrup
Conduct sound vibrations: tympanum, hammer, anvil, stirrup, oval window, cochlea
Semicircular canals – three fluid-filled tiny canals, assist in balance

20. Stirrup
Hammer
Oval window
Anvil
Semicircular canals
Cochlear nerve
Cochlea
Bone
Auditory canal
Tympanum
Eustachian tube
Round window

21. Taste buds – on the tongue, detect taste

22. Smell – detected by olfactory bulbs in nasal passages
Touch – skin has sensory receptors to temperature, touch, and pain

23. Drugs that affect the nervous system:
Stimulants – increase actions (heart rate, increase neurotransmitters in brain)
Include: caffeine, nicotine, cocaine
Depressants – decrease activity (heart rate)
Include: marijuana, alcohol