THE
CENTRAL NERVOUS SYSTEM (CNS) &
THE PERIPHERAL NERVOUS SYSTEM (PNS)
BIO 1007 Lecture Outlines | BIO 1007 Resources | Mrs. Caley Opsal's Home | IVCC Home | Contact Us
I. Connective Tissue Coverings of the Brain and Spinal Cord (meninges)
A. Dura Mater ("Tough Mother"...and it is!)
1. Tough, white fibrous CT (two layers)
2. Dural sinuses - blood vessels that drain venous blood and cerebrospinal fluid
3. Epidural space - between Dura Mater and vertebrae
B. Arachnoid Mater
1. Thin, web-like membrane of epithelial cells and thin collagen and elastic fibers
2. Subarachnoid space - contains cerebrospinal fluid (CSF)
3. Arachnoid granulations (villi) - drain CSF and deposit it in the dural sinuses
C. Pia Mater
1. Thin, innermost layer that lies on the nervous tissue of the brain like a "hair net"
2. Contains an abundance of blood vessels
3. Nourishment
D. Meningitis
II. Areas of the Brain
A. Cerebrum
1. Structure
a. Cerebral hemispheres
b. Corpus callosum
c. Gyri (long i) (sing. Gyrus)
d. Sulci (long i) (sing. Sulcus)
e. Fissures
f. Lobes
1. Frontal
2. Parietal
3. Temporal
4. Occipital
5. Insula
g. Cerebral cortex -
h. Inner white matter with islands of gray matter (Basal or Cerebral Nuclei) mixed in
2. Functions of the Cerebrum
a. Sensory
b. Motor
c. Memory
d. Personality
e. Learning and reasoning
3. Motor Areas of the Cerebral Cortex
a. Primary Motor Cortex ¸ precentral gyrus
- Pyramidal cells here (pyramidal tracts in spinal cord)
b. Broca's Area (also called the Motor Speech Area)
4. Sensory Areas of the Cerebral Cortex
a. Primary Somatosensory Cortex
b. Primary Visual Cortex
c. Primary Auditory Cortex
d. Olfactory Area
e. Wernicke's Area - (usually left side)
5. Association Areas - connections between sensory and motor areas
a. Analyze and interpret sensory information
b. Coordinate motor responses
c. Reasoning, verbalizing and judgment
d. Emotions
Visual Association Area - anterior to Primary Visual Cortex; involved with combining visual images with other sensory experiences (i.e. recognizing your friend/mother/brother, etc...).
Prefrontal Cortex - anterior portion of frontal lobe; involved with elaboration of thought, intelligence, motivation & personality; judgment, persistence, planning, consciousness.
6. Hemisphere Dominance - >90% population is left-side dominant for speech, writing and reading.
7. Memory - Each of the approximately 10 billion neurons in the cerebral cortex can make tens of thousands of synaptic connections to other neurons...a potential for 60 trillion synapses!!! One area of the brain, the hippocampus is involved, among others.
8. Cerebral (Basal) Nuclei (or Basal Ganglia)
a. Clusters of gray matter deep within the cerebrum
b. Consists of Caudate nucleus, Putamen, and Globus pallidus
c. Functions:
1. Inhibits excessive movements
2. Involuntary control of motor activity
3. Involved with the patterns and rhythm associated with movements like walking (especially stopping the act of walking)
d. Parkinson's Disease is due to deficiencies of the neurotransmitter _________________________
Symptoms:
1. Increased muscle tone or rigidity
2. Resting tremors
3. Slowness in motor behaviors
9. Ventricles - cavities within the brain
a. Lateral ventricles (right and left)
b. Interventricular Foramen (of Monroe)
c. Third ventricle
d. Cerebral (Mesencephalic) aqueduct
e. Fourth ventricle
f. Subarachnoid space and central canal of the spinal cord
g. Cerebrospinal fluid (CSF)1. Produced continuously by ____________ __________ with the help of these glial cells:______________________
2. Clear, somewhat viscous fluid
3. Cushions brain and spinal cord
4. Nutritive and carries wastes away
5. Reabsorbed by __________________________
6. Lumbar punctures (spinal taps, see page 72 in Applications Manual) - to obtain samples of CSF from the lumbar region of the spine
B. Diencephalon = Thalamus and Hypothalamus
1. Important structures near the diencephalon:
a. Optic Tracts -
b. Optic chiasma (chiasm = a crossing over or decussation)-
c. Pituitary gland
1. Anterior pituitary (adenohypophysis)
2. Posterior pituitary (neurohypophysis)
d. Mammilary bodies - pea-like nuclei involved with olfaction and swallowing reflexes
e. Pineal gland - endocrine organ that may be involved with sleep-wake cycles and responses to light
2. Thalamus
a. Relay station for sensory information (except olfaction)
b. Filters much useless sensory information
c. Coordination of motor commands (voluntary and involuntary)
3. Hypothalamus
a. A neuroendocrine organ - what does this mean??
b. Direct neural connection to the posterior pituitary
c. Neural functions include:
1. Heart rate and blood pressure
2. Body temperature
3. Water and electrolyte balance
4. Hunger
5. Peristalsis and glandular secretions
6. Sleep and wakefulness
d. Endocrine functions include:
1. Production of the hormones antidiuretic hormone (ADH) and oxytocin
2. Produces "releasing" and "inhibiting" hormones that control the release of hormones from the anterior pituitary
C. Brain Stem (Midbrain, Pons, and Medulla)
1. Midbrain
a. Cerebral (Mesencephalic) aqueduct
b. Cerebral peduncles
c. Corpora Quadrigemina: the "butts" of the brain!
1. Superior colliculi -
2. Inferior colliculi -
2. Pons
a. Ascending, descending and transverse fiber tracts
b. Connects the cerebellum with the brain stem
c. Pons nuclei -
3. Medulla oblongata (Medulla)
a. Ascending and descending tracts cross over here ______________________________
b. Vital Reflex Centers
1. Cardiac center
2. Respiratory center
3. Vasomotor center
D. Other Functional Areas of the Brain
1. Limbic system - our "emotional brain" (a more "primitive" brain area)
a. Major structures include the hippocampus, hypothalamus, thalamus, mammilary bodies, and amygdala.
b. Olfaction
c. Links our emotions with visceral responses (hypothalamus)
d. Tightly tied with our cognitive brain (cerebral cortex)
2. Reticular Formation - a group of neurons with an important job (especially for night students taking 3-hour classes!)
E. Cerebellum
1. Folia -
2. Arbor vitae -
2. Functions
a. Equilibrium and balance
b. Proprioception
II. The Spinal Cord
A. Structure of the Spinal Cord
1. 31 segments
2. Cervical enlargement - gives rise to nerves of the upper limbs
3. Lumbar enlargement - gives rise to nerves of the lower limbs
4. Conus medullaris - inferior "tip" of the cord (approx. at level of L2)
5. Filum terminale - continuation of pia mater at the conus medullaris
6. Cauda equina - from L2-S5, nerve roots from inferior aspect of spinal cord
B. Cross section of the Spinal Cord: Be able to sketch one and label the following:
1. Inner gray matter, outer white matter
2. Anterior, lateral and posterior horns
3. Central canal (contains CSF)
4. Dorsal and ventral roots outside of the spinal cord
5. Dorsal root ganglion (sensory neuron cell bodies)
6. Dorsal root + ventral root = spinal nerve (mixed nerve)
C. Functions of the Spinal Cord
1. Conduction of Nerve Impulses along....
a. Ascending tracts -
1. Posterior White Column Pathways
2. Anterior White Column Pathways
3. Lateral White Column Pathwaysb. Descending tracts -
1. Corticospinal ("Pyramidal") tracts -
2. Reflex center
a. Patellar reflex - see handout
b. Withdrawal reflex
III. Homeostatic Imbalances of the Nervous System (see Applications Manual for details)
A. Cerebrovascular Accident (CVA)
B. Transient Ischemic Attack (TIA)
C. Alzheimer's Disease
D. Huntington's Disease
E. Multiple Sclerosis
A. Cervical nerves C1 - C8
B. Thoracic nerves T1 - T12
C. Lumbar nerves L1 - L5
D. Sacral nerves S1 - S5
E. Coccygeal nerves C0
Remember: each spinal nerve = dorsal root + ventral root (a mixed nerve)
Dorsal root =
Ventral root =Dermatomes - "maps" of areas of the skin in which the spinal nerves innervate
II. Plexuses
A. Cervical Plexus
-Phrenic nerve
B. Brachial Plexus
-major nerves formed from this plexus are: ulnar, median, radial & axillary
C. Lumbosacral Plexuses
-the longest and thickest nerve in the body, the Sciatic nerve, arises here
Last Updated 05/26/06