BIOD 331/BIOD 331 Module 6(Complete Solution)Latest Updated A+ Score Guide Solution/

BIOD 331 Module 6(Complete Solution)

(Organization & Function of Nervous System I


I. Nervous System Overview

● Acts as the control center, receiving sensory input, integrating information, and
producing responses.
○ SENSATION (Sensory receptor) sensory neurons →INTEGRATION (percept)
Motor neurons → REACTION (effectors - skeletal muscle, heart muscle as an
example)

● Divided into:

○ Central NS (brain + spinal cord); vital organs, cant be regenerated, so encased in
meninges, membranes and skeleton → integration and processing.
■ Brain can be subdivided into 3 regions:
● The hindbrain
● The midbrain
● The forebrain

○ Peripheral NS (nerves outside CNS); sensory receptors, cranial nerves, spinal
nerves → carries info to/from CNS.
■ Autonomic division - involuntary - innervating internal organs - glands and
smooth muscles
● sympathetic nervous system SNS - activates and prepares body
for vigorous muscular, activity, stress, and emergencies
● parasympathetic nervous system PNS - normal resting
situations, permitting digestions and conservation of energy ■
Somatic division - voluntary - skeletal muscles, skin and joints


II. Central Nervous System

● HINDBRAIN: Affected by sleep disorders and cerebrovascular accidents (CVAs).
○ Cerebellum (coordination, posture, balance), Pons, Medulla (vital functions like
respiration/HR).

● MIDBRAIN: the tracts are main motor nerve pathway - area regulates eye movement,
visual and auditory processing
○ Cerebral peduncles, bundle of nerve fibers that make up the corticospinal tracts.

, ● FOREBRAIN: most rostral part of brain (towards nose)
○ diencephalon (thalamus and subthalamus, hypothalamus)

○ cerebral hemispheres (lobes) connected via corpus callosum

■ Frontal: motor control, planning, judgment.

■ Parietal: sensory input.

■ Temporal: auditory processing, memory.

■ Occipital: vision.

● Basal ganglia: masses of white matter located deep to the cerebral cortex
○ Unlearned postural movements, smooth movements; dysfunction = Parkinson’s.

● Limbic system: located toward the medial aspect of the cerebrum
○ emotion; stimulation in this area = pleasure, anxiety, rage, etc


III. Spinal Cord

● Extends skull → L1/L2; continues as cauda equina which are ventral and dorsal nerve
roots that extend beyond the cord itself.

● Oval in shape

● Tissue divisions:

○ Gray matter: butterfly shape, contains cell bodies of neurons. Extensions are
horns.
■ Dorsal horn: sensory input (afferent) - from periphery
● Posteriorly within the cord, they receive sensory info by way of
afferent neurons from periphery to be transmitted and interpreted
■ Ventral horn: motor output (efferent) - to periphery
● Contain different efferent neurons which carry motor info from
CNS to periphery
○ White matter: myelinated tracts (ascending sensory, descending motor).


IV. Protective Systems

● Meninges: connective tissue sheaths that surround the brain and spinal cord

, ○ The pia mater (innermost, blood vessels)
○ arachnoid (encases the entire CNS, non vascular and water proof - subarachnoid
space is where CSF circulates)
○ The dura mater (tough outer).

● CSF: cushions, nutrient/waste exchange; produced by choroid plexus.

● Ventricles: lateral → 3rd → aqueduct → 4th → subarachnoid space.

Peripheral Nervous System

● Made up of nerves and ganglia located outside of CNS.
○ 12 pairs of cranial nerves
○ Also includes 31 pairs of spinal nerves original from spinal cord that innervate the
entire body
■ Cervical nerves - 8 pairs
■ Thoracic nerves - 12 pairs
■ Lumbar nerves - 5 pairs
■ Sacral nerves - 5 pairs
■ Coccygeal nerves - 1 pair
V. Cranial Nerves (I–XII) PNS

1. I Olfactory Sense of SMELL - olfaction

2. II Optic Sense of sight - VISION

3. III Oculomotor PUPILLARY constriction, accommodation, EYE movement and EYE
LID movement

4. IV Trochlear Movement of EYE DOWN and INWARD

5. V Trigeminal Mastication (chewing), sensation to face, nose, and mouth

6. VI Abducens EYE LATERAL movement

7. VII Facial Fascial expression, anterior tongue taste

8. VIII Vestibulocochlear HEARING, balance, equilibrium

9. IX Glossopharyngeal SWALLOWING muscles, posterior tongue taste

10. X Vagus Digestion, HR REG, sensation in digestive tract

11. XI Accessory Cervical rotator muscles, trapezius muscle

, 12. XII Hypoglossal Voluntary TONGUE movements

Sample exam questions for this section

1. Lateral eye movement issues - Cranial nerve VI
2. Voluntary tongue movements which cranial nerve - Cranial nerve XII
3. Each of the following are true regarding org of nervous system EXCEPT (pick out FALSE
statement)

a. The PNS has an afferent and efferent division (true)

b. The somatic nervous system can be further divided into the sympathetic and
parasympathetic divisions (false - autonomic nervous system is divided into
sympathetic and parasympathetic nervous system

c. The CNS contains the hindbrain, midbrain, and forebrain (true)

d. The PNS contains the cranial nerves (true)

4. Each of the following statements is true regarding the organization of the nervous system
EXCEPT, select ALL that apply:
a. CNS has an efferent and afferent division (false - PNS)
b. The autonomic nervous system can be divided further into the sympathetic and
parasympathetic divisions (true)
c. The CNS contains cranial nerves (false)
d. The PNS contains spinal nerves (true)
5. Efferent neurons deliver ___input from CNS to the periphery Answer:
Motor
6. ___neurons delivery sensory input from periphery to CNS Answer:
Afferent
7. The _____houses the cerebral peduncles Answer: Midbrain
8. Specialized ependymal cells that project into the ventricles and
produce CSF are called
___
Answer: Choroid Plexus
9. Connective tissue that sheaths that surround the brain and spinal
cord providing protection are called the ____
Answer: Meninges