2. Essential Understandings
 Describe the basic structure of a neuron, and compare the functions of the
three classes of neurons.
 Explain how a nerve impulse is transmitted across a chemical synapse
 List the major regions of the brain and the main functions of each region.
 Describe the overall anatomy of the peripheral nervous system, including the
cranial nerves and spinal nerves.
 Explain how the somatic system differs from the autonomic system.
 Contrast the overall functions of the sympathetic and para-sympathetic
divisions of the autonomic nervous system.
 List all tissues that light passes through from when it enters the eye until it is
converted into a nerve impulse.
 Discuss the role of rods and cones in transducing a light stimulus into a nerve
impulse
 Distinguish the parts of the ear that make up the outer ear, middle ear, and
inner ear.
 Describe the mechanism by which sound waves in the outer ear are converted
into nerve impulses in the inner ear.

3. Regulation Processes by which a stable internal environment is kept.
Regulation is brought about by the Nervous and Endocrine system.
Neuron Cell specialized in transmitting impulses – a nerve cell
Dendrites part of nerve cell that receives impulses, towards the cell body
Axon carries impulses away from the cell body of a neuron
Terminal Branches The axons end that is in contact with another cell.
Synapse The GAP between the terminal branch and another cell.
Neurotransmitters Chemicals released from the tip of an axon into the
synapse when a nerve impulse arrives;
may stimulate or inhibit the next neuron

4. Nerves A bundle of axons or fibers, bound together.
Sensory neurons carry signals from receptors & transmit
information to brain and spinal cord
Motor neurons carry signals from central nervous system to the
muscles and glands.
Inter neurons process signals from one sensory neurons and relay
signals to motor neurons.
Receptors receive stimuli from the environment. The sense organs
Effectors A muscle or a gland that responds to a stimuli.
Reflex arc Pathway of sensory receptors ,neurons, effector(s)
that participate in a reflex

5. Central Nervous system (CNS)
Cerebrum part of the forebrain, associated with higher functions,
including language and abstract thought
Cerebellum concerned with fine motor coordination and body
movement, posture, and balance;
Medulla The region of the brain that, controls heart rate, constriction
and dilation of blood vessels, respiration, and digestion.
Spinal Cord receives sensory information and sends output motor signals;
with the brain, forms the central nervous system.
Peripheral nervous system
Somatic Nervous system -neurons that connect the CNS to skeletal
muscles (voluntary), the skin & sense organs
Autonomic nervous system Serves the internal organs of the body,
Usually no voluntary control. Ex. breathing
Malfunctions: Alzheimer’s, Parkinson’s, Multiple Sclerosis, stroke…

6. Brain
Spinal Cord
Peripheral nerves

7. Cerebrum
Cerebellum Medulla
Spinal Cord

9. Nucleus
More information
Dendrites
axon
Synapse
Myelin Sheath
Terminal Branch

13. How many neurons (nerve cells) are in the brain? How big are they?
It is estimated that there are 100 billion (100,000,000,000) neurons
in the human brain. To get an idea of how many 100 billion is, think
of this:
Assume that you were going to count all 100 billion cells at a rate of
1 cell per second. How long would it take you to count all 100 billion
cells? Calculations say it would take about 3,171 years!!!.

16. Central Nervous System
brain spinal cord
Peripheral Nervous System
cranial nerves spinal nerves
sensory fibers motor fibers
somatic nervous autonomic nervous
system (to skeletal system (to smooth
muscles) muscle, cardiac
muscle, and glands)
sympathetic parasympathetic
division division

17. Peripheral Nervous System
 Any neurons outside of the CNS.
 Sensory Division –
 bringsin stimuli from external environment
 monitors status of internal environment
 Motor Division –
 Somatic – carries signals to skeletal muscles
 Autonomic – coordinates functions of organs and
helps maintain homeostasis.
 Sympathetic and Parasympathetic
 Oftenhave opposite effects on the body.
 One system stimulates, the other inhibits

20. The
Sense
Organs

21. The
EYE

23. Main Parts of the Eye
 Cornea – light enters, transparent layer of cells
 Aqueous Humor – in anterior chamber, light passes
through
 Iris – colored part; regulates size of pupil
 Pupil – black dot; opening; light enters inner eye
 Lens – behind pupil; focuses light onto retina
 Vitreous Humor – fluid behind lens
 Retina – has photoreceptors
 Rods – black and white; extremely sensitive to light
 Cones – color, less sensitive to light. Concentrated in the
FOVEA.
 Optic Nerve – Carries impulses to the brain.
 Sclera and Choroid – outer layers of the eye

24. The EAR

25. Outer Ear
 Auricle (Pinna) – visible part of the ear.
Collects sound
 Auditory Canal – sound enters,
ear canal
 Tympanum(eardrum) -
membrane. Vibrates

26. Middle Ear
 Hammer(malleus) – bone…attached to
eardrum…accepts vibrations and
passes them to
 Anvil(incus) – bone – accepts
vibrations and passes them to
 Stirrup(stapes) = bone – accepts
vibrations and passes them to the Oval
Window

27. Inner Ear
 Oval Window – attached to stirrup…
creates pressure waves in the cochlea
 Cochlea - snail like. Fluid filled. Lined
with tiny sensory cilia that produce
nerve impulse…….taken to the…
 Auditory Nerve(cochlear nerve) – takes
impulse to the brain

28. Eustachian Tube
Connectthe EAR,
NOSE, AND THROAT

29. BALANCE
 Semicircular Canals – helps CNS maintain
balance and your sense of equilibrium.
 Filled with fluid…lined with ciliary sensory
nerves.
 When your head changes position, the
hairs sense and send impulses to the
brain.

30. TASTE AND SMELL
 Smell – chemoreceptor in the lining of
the nasal passages.
 Taste – taste buds on the tongue.
Sensitivity to taste varies on the area of
the tongue.
 Sweet, sour, bitter, salty.

33. Touch
 Not found in one particular place.
 All skin regions are sensitive to touch.
 Temperature (Hot and Cold), Pain,
Pressure, light touch.
 Greatest concentration of touch
receptors: face, hand, toes