Download HAP Study Guide: Nervous System and Special Senses

HAP Study Guide: Nervous System and Special Senses
Test will be on Monday, April 2, 2012
Chap. 12: Neural Tissue
 3 Functions (describe)
o Sensory input: Input from special senses, internal receptors (hunger, thirst, etc)
o Integration: Combining all available sensory input to make decision
o Motor output: reacting to sensory input based on integration to create muscle or
gland response.
 Organization
Anatomical
o CNS: Central Nervous System; includes brain and spinal cord.
Integration center/decision maker
o PNS: Peripheral Nervous System, includes all neurons not in CNS
Responsible for sensory input and motor output
Functional
o Sensory: Collect information from special senses and internal temperature,
hunger, thirst, blood sugar, blood pressure, etc sensors.
o Motor: React to integration center command to illicit response through activation
of skeletal muscle, smooth muscle, cardiac muscle, or gland response.
 Structure of Neurons
o Cell body: Metabolic center of the cell; contains nucleus and organelles
o Axon: Extension of cell body that transmits impulse AWAY from cell body
o Dendrite: Extension of cell body that transmits impulse TOWARD cell body
o Synapse: Gap between axon of one neuron and dendrite of next neuron
 Neurotransmitters: Chemical messenger released from axon terminal of
one neuron to bridge the synapse and activate the dendrite of the next
neuron
o Structural classification:
 Multipolar: Most common in CNS; multiple dendrites and single axon
 Bipolar: Found in special senses of eyes; single dendrite and single axon
 Unipolar: Found in touch receptors; single extension with cell body pushed
to side
 Anaxonic: multiple dendrites and single axon; cannot tell difference
between dendrites and axon
 Neuroglia: Function to……
o Astrocytes: Most numerous; supports axons and holds neurons in place
o Microglia: Phagocytic immune cells on CNS
o Ependymal cells: Line ventricles (spaces in brain) to produce cerebrospinal fluid
o Oligodendrocytes: Insulating cells of CNS
o Schwann cells: Insulting cells outside of CNS
Chap 14: Brain and Cranial Nerves
Figure 14-1: Introduction to Brain Structures and Functions.
 Cerebrum
o High-order thinking, processing, and sensory integration
o Memory storage
o Language processing and production
 Diencephalon
o Thalamus
 Traffic cop/relay center
o Hypothalamus
 Interacts with Endocrine System and hormone production
 Mesencephalon
o Relay Center
o Controls consciousness
o Visual integration
 Pons
o Relay center for sensory input
o Visceral motor response
 Medulla Oblongata
o Respiration and heart rate
o Temperature control
 Cerebellum
o Coordination of muscle movement
Cranial Nerves (See table from notes)
Chap. 15/16: Somatic/Autonomic Nervous System
 Somatic Nervous System: responsible for skeletal muscle response
 Autonomic Nervous System: responsible for smooth muscle, cardiac muscle, and gland
response
o Important for maintaining Homeostasis: maintaining a constant internal
environment even though the external environment is constantly changing
o Two “arms” of the ANS
 Sympathetic AKA Fight or Flight Response.
 Parasympathetic AKA Resting and Digesting.
Chap 17: Special Senses/Vision
 Accessory Structures of the Eye
o Conjuctiva: lining of inner eyelid and outer surface of cornea. Infection is called
conjunctivitis or Pink Eye.
o Lacrimal glands: Creates tears
o Tears: products of lacrimal glands; contains enzymes that offer immune protection
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Layers of the Eye
o Fibrous Tunic: Offers protection and support to the eye
 Cornea: Clear window on front of eye
 Sclera: White of the eye
o
Vascular Tunic: AKA Choroid Layer. Provides blood supply to the eye. Also contains:
Iris = colored portion of eye
Ciliary muscle = controls shape of lens
o
Neural (Sensory) Tunic: contains rods and cones, the photoreceptors that collect light to
transmit to the brain through the optic nerve
Fovea centralis is the pit of “perfect focus”
Chambers of the Eye
o Anterior chamber: between cornea and lens; contains the watery Aqueous Humor
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Posterior chamber: located behind lens; contains the jelly-like Vitreous Humor
Vision
o What is the order of structures/substances that light passes through?
1. Cornea
2. Aqueous Humor
3. Lens
4. Vitreous Humor
What is accommodation? The ability to focus light by changing the shape of the lens for far and
near vision.
The retina collects the light information in specialized photoreceptor cells called RODS and
CONES. Axons carry the impulses received from each of these receptors cells and are bundled
together on the posterior aspect of the eye. The leave the eye via the OPTIC NERVE.
The fibers from the medial side of each eye cross over to the opposite side of the brain at the
OPTIC CHAISM. This allows the visual fields to overlap, providing BINOCULAR VISION and DEPTH
PERCEPTION.
Emmetropia: perfect vision; 20/20
Hyperopia: Far-sighted; not common; glasses needed for reading not for far vision.
Myopia: Near-sighted; most common reason to wear lenses; glasses needed for far vision.
Presbyopia: Aging eyes; Lenses lose elasticity as aging happens requiring glasses for reading focus
Hemianopia: “without half vision”; blindness on one side of visual field.
Astigmatism: imperfection of cornea that scatters light as it enters the eye causing blurriness in one
location.
Glaucoma: Increase intraocular aqueous humor pressure; can damage retina and lead to blindness