Nervous System Study Guide

Green Handout
	Events in Nerve Cell
1	Acetylcholine placed on Nerve Cell (Dendrite)
2	Charge outside of cell membrane changes from + to – (because NA^+ moves into the cell) Action Potential – change of cell membrane from positive to negative
3	CA^++ is released from the synaptic vesicles within the axonal terminals

1. The nucleus of a nerve cell (neuron) is in what part of the cell? (pg 390) The Cell Body

2. What carries the impulse away from the nerve cell body? (pg 392) The Axon

What carries the impulse toward the nerve cell body? The Dendrite

3. Define Saltatory conduction. (pg 406) The action potentials are triggered only at the Nodes of Ranvier; the part of the axon not covered with myelin. The electrical signal jumps from node to node in quick succession; drastically increases the speed of the signal

4. What is the Neuroglia that makes myelin sheaths? (pg 389-390) Schwann Cells in the peripheral nervous system (PNS); Oligodendrocytes in the central nervous system

What is the function of the myelin sheath? To increase the speed of transmission of nerve impulses

What is the myelin sheath composed of? Primarily Fat

What are the gaps in the sheath formed between? Schwann Cells

What are the nodes of Ranvier? The gaps in the myelin sheath between the Schwann cells

What parts of the neuro may be myelinated? The Axon (only)

What is the white colored matter of the brain and spinal cord from? The myelin sheath on the Axons

5. Repair of the axons and dendrites in the peripheral nervous system can occur if the nerve cell bodies are intact and if the Neurilemma is intact.

Is there repair in the central nervous system? No regeneration because there is no Neurilemma; the cell body of the Schwann cell located on the myelin

At what age do all neurons lose the ability to undergo mitosis? Before birth; at 6 months after fertilization

6. What does a buildup of neurotransmitter by a single nerve cell that has fired two or more times result in? Temporal Summation

7. Look at White Handout : Nerve Reflux Arc

In order, name the components of a reflex arc.

	Components	Description / Location / Path
1	Receptor	Along Dendrite; In through Dorsal Root
2	Sensory Neuron	Dorsal Root Ganglion; cell body; In Dorsal Root; into Spinal Cord
3	Association Neuron	Not always present; In Spinal Cord or Brain
4	Integrating Center	Anterior (ventral) horn of grey matter; Site of Polio problems
5	Motor Neuron	Along Ventral Root; out to effector; Down Axon
6	Effector	Example: Neuro-Muscular Junction

Name examples of effectors. Any Muscle

Name examples of receptors. Merkel’s discs; Meissner’s corpuscles; Ruffini’s corpuscles; Pacinian corpuscles; etc.

What is the tapping of the knee an example of? The Stretch Reflex

Motor (efferent) nerve cells conduct impulses in what direction? Away from the spinal cord

Sensory (afferent) nerve cells conduct impulses in what direction? Toward the spinal cord

All spinal nerves are mixed nerves. What does that mean? (pg 480) They contain Sensory and Motor fibers

What part of the spinal nerve only has sensory (afferent) cells? The Dorsal Root

What part of the spinal nerve only has motor (efferent) nerve cells? The Ventral Root

The dorsal root ganglion contains nerve cell bodies of the sensory nerve cells.

What structure does the Polio virus attack? The Anterior horn of the grey matter

What part of the spinal cord is the integrating center between sensory and motor nerve cells? The Grey Matter

What are nerve cell bodies in the peripheral nervous system called? Ganglion; in the dorsal root

Central Nervous System (CNS)

8. What is the cauda equina formed from? (pg 462-63) The spinal nerves that extend from the end of the spinal cord

Between what vertebrae is a needle inserted during a spinal tap (lumber puncture)? L₃ & L₄ or L₄ & L₅

9. What is found in the central canal of the spinal cord? Cerebral Spinal Fluid

What is the superior end of the central canal continuous with? The 4^th Ventricle of the brain

What is the color of the matter next to the central canal? Grey

Which foramen in the skull does the spinal cord pass through? The Foramen Magnum

At what vertebra does the spinal cord begin? C₁

At what vertebra does the spinal cord end? L₁

10. Name and locate the 3 meninges of the central nervous system. (pg 454-455)

1. Pia meter; clings tightly to Brain and Spinal Cord

2. Arachnoid mater; loose brain covering; creates subarachnoid space between itself and the Pia Mater

3. Dura mater; superficial to and in contact with the Arachnoid Mater; usually double layers

In what two general areas of the brain does cerebral spinal fluid (CSF) circulate?

1. Ventricles & Central Canal

2. Subarachnoid space

What does the epidural space contain? Fat; padding; site for injection of anesthetic during childbirth

What is the dura mater composed of? Dense irregular connective tissue

What is the name of the highly vascular, innermost meninx? The Pia Mater

What is the middle avascular meninx? The Arachnoid Mater

The superior sagittal sinus is found between 2 layers of what? Dura Mater

This and all other sinuses in the CNS contain what? Extra cerebral spinal fluid

11. Spina Bifida and Anencephaly are defects in what? (pg 468-469) No formation of the ventricles & canal; called Neural 2 Defects

These defects are associated with the lack of what in the diet of the mother? Folic Acid

12. What is the connective tissue covering individual nerve cells called? Endoneurium

Spinal Nerves (pg 491 – 493)

13. What is the largest nerve in the body? The Sciatic nerve

What plexus is this nerve a part of? (pg 499) The Sacral Plexus

What nerve stimulates the diaphragm? (pg 494) The Phrenic Nerve

If a patient is on a respirator, this patient has damage to what plexus? (pg 494) The Cervical Plexus

What nerves are involved in this situation? C₁ – C₄

Vertebrae C₅ through C₈ form what plexus? (pg 496) The Brachial Plexus – nerves to the arm

Brain

14. Describe the function of the arachnoid villi. They are projections of the Arachnoid Mater through the first layer of Dura Mater that allow the flow of extra CSF into the Dura sinuses; leading to the drainage of extra CSF into the internal jugular vein

15. Locate the four ventricles of the brain. (pg 432-433)

1^st & 2^nd – Left & Right Lateral ventricles; look like horns of big horn sheep; in the cerebral hemispheres

3^rd – at the Thalamus; the Ventricle is surrounded by the Thalamus

4^th – just dorsal of Pons & Medulla

What are cavities within the brain called? Ventricles

Where is Cerebral Spinal Fluid made? In the ventricles; at the choroid plexus, on the roof of several ventricles

What does the blockage of the flow of CSF result in? Hydrocephaly; too much CSF in the ventricles; leads to swelling of the head in infants

16. Locate and name the parts of the human brain. (pg 449) See Table below

What part is involved in body coordination and balance? Cerebellum

What part is involved in body temperature control? Hypothalamus

What part is involved in habitual or automatic actions in sequence like walking? Basal Ganglia

What part of grey matter in the cerebrum affects muscle tone? Basal Ganglia

What grey matter is the site of crude localization of sensory input? In the Thalamus

What is the relay center between the spinal cord and the cerebral cortex? Thalamus

What is the function of the Thalamus? Crude sensory perception; relay station between the spinal cord and cerebral cortex

What part of the brain affects involuntary emotions? The Limbic System

What does the pineal gland make? Melatonin

What does this hormone promote? Sleepiness

What makes the hormones secreted by the posterior lobe of the pituitary gland? Hypothalamus

What controls the secretion anterior and posterior lobes of the pituitary gland? Hypothalamus

What makes up the brain stem? Medulla (bottom), Pons (middle), Midbrain (top)

What is the significance of the decussation of pyramids? If there is damage to the left side of the brain the right side of the body is affected; area of crossing

What controls the diameter of the blood vessels? Medulla

What controls swallowing, vomiting, and coughing? Medulla

Where are the pneumotaxic and apneustic centers located? In the Pons; regulate rhythm of breathing

What are white fibers that are attached to the opposite cerebral hemisphere? The Corpus Callosum

What does damage to the cerebellum cause? Ataxia; drunken movements

Major Brain Regions and Functions
Cerebral Hemispheres
Cortical Grey Matter		Localizes and interprets sensory inputs	Controls voluntary and skilled skeletal muscle activity			Functions in intellectual & emotional processing
Basal Ganglia		Subcortical motor centers	important in initiation of skeletal muscle movements			Gross motor movement and muscle tone
Diencephalon
Thalamus		Crude sensory perception		Relay station between the spinal cord and cerebral cortex; cerebral cortex & lower motor centers			Involved in memory processing
Hypothalamus		Aids the Medulla in automatic (involuntary) nervous system		Regulates body temperature, food intake, water balance, thirst, bio rhythms & drives			Regulate hormone output of anterior pituitary gland
Hypothalamus		Part of the Limbic System along with cerebral structures		Makes two hormones; mediates emotional “gut” feelings			Involved in memory processing
Brain Stem
Pineal Gland	Makes Melatonin				Helps put you asleep
Midbrain	Conduction pathway between higher and lower brain centers				Visual & auditory reflex centers			Subcortical motor centers
Pons	Works with Medulla to control respiratory rate and depth				Relay information between the cerebrum & cerebellum
Medulla Oblongata	Site of decussation of pyramids – where left & right functions criss-cross				Controls heart rte, blood vessel diameter, respiratory rate, vomiting, coughing, etc.			Sensory relay to cerebellum
Cerebellum
	Controls coordination, balance, posture		Controls learned fine motor movements				Damage results in Ataxia; drunken movements

Cerebral Cortex

Cerebral Cortex
Frontal Lobe
Area		Location	Function		Damaged Behavior
Primary Somatomotor Cortex		Precentral Gyrus; anterior of central sulcus	Consciously control the precise or skilled voluntary movements of skeletal muscles		Unable to control movements of skeletal muscles
Premotor Cortex		Just anterior to Precentral Gyrus	Controls learned motor skills of repetitious or patterned nature (playing instrument); planning movements		Forget how to play instruments or other planned or learned skills
Broca’s Area		Anterior to the inferior part of Precentral Gyrus; Usually only in Left Hemisphere	(1)Motor Speech Area – directs the muscles of the tongue, throat, lips involved in speech production; (2)active when prepare to speak; (3)think about many voluntary motor activities		Problems with speech formulation; thinking about other motor functions
Frontal Eye Field		Partially in & anterior to Premotor Cortex; Superior to Broca’s Area	Controls voluntary movement of the eyes		Unable to look at what you want
Parietal Lobe
Primary Somatosensory Cortex		Postcentral Gyrus; posterior of central sulcus	Receive information from sensory receptors in skin & proprioceptors in skeletal muscles; identify the body region being stimulated – Spatial Discrimination			Unable to feel stimulation of skin or have spatial awareness
Somato-sensory Association Cortex		Just posterior to the primary somatosensory cortex	Integrate different sensory inputs from somtosensory cortex to have comprehensive understanding of an object being felt; i.e. reaching in pocket and recognizing coins or keys			Can not recognize objects without looking at them
Gustatory (Taste) Cortex		Just deep of the Temporal Lobe; in the postcentral gyrus	Involved in the perception of taste stimuli			Unable to taste
Occipital Lobe
Primary Visual Cortex	Extreme posterior tip of occipital lobe; most buried in medial aspect of lobe			Receives visual information that originates on the retinas of the eyes		Results in functional blindness; unable to see
Visual Association Area	Surrounds the primary visual cortex; covers much of the lobe			Interprets visual stimuli using past experiences; enable us to recognize & appreciate objects		Can see but unable to comprehend what we are seeing
Temporal Lobe
Primary Auditory Cortex	Superior margin of temporal lobe abutting lateral sulcus			Receives auditory information from cochlear receptors		Results in functional hearing loss
Auditory Association Area	More posterior of the Primary Auditory Cortex			Permits perception of sound stimulus; to “hear” as speech, music, noise, etc.		Can hear but unable to comprehend what we are hearing
Olfactory (smell) Cortex	Medial aspects of temporal lobe & in Frontal lobe just above the orbits			Receive input from receptors in nasal cavities; results in conscious awareness of odors		Unable to process and comprehend odors

17. Locate and describe the function of the parts of the cerebral cortex. (pg 434) See above table

Predict what might happen to behavior if each lobe was damaged. See table above

The somatomotor is in what gyrus? Frontal (precentral)

The somatosensory is in what gyrus? Parietal (postcentral); behind the dividing line

Locating sensory information is the function of what part of the cortex? Somatosensory

Most conscious sensation are interpreted and relayed by what? The Thalamus

After the Thalamus nerve impulses go to what lobe of the cortex? The Parietal or Somatosensory part of the Parietal lobe

What are the four kinds of brain waves generated by the cortex?

Alpha – just awoken; not really thinking clearly

Beta – focusing; thinking; concentration; REM- restorative

Theta – having a crisis

Delta – when you are asleep; Non-REM sleep

What are the functions of the reticular activating system? It helps keep you awake; Reticular Formation

What structures have proprioceptors? Skeletal Muscle; it is the sense of where your body parts are in relation to your environment; without sight or sound

Nerve Arc for Actions that Require the Brain At Least 5 Nerves
		Location of Cell Body	From	To
1	1^st Order Sensory	Dorsal Root	Receptor (skin)	Spinal Cord
2	2^nd Order Sensory	Spinal Cord	Spinal Cord	Thalamus
3	3^rd Order Sensory	Thalamus	Thalamus	Cerebral Cortex
4	Upper Motor	Cerebral Cortex	Cerebral Cortex	Spinal Cord
5	Lower Motor	Anterior Horn	Spinal Cord	Muscle

18. Where are the cell bodies of the first order sensory neuron located? (pg 537) In the Dorsal Root

What does the first order sensory neuron conduct impulses from to the CNS? From the Receptor (i.e. skin) to the Spinal Cord

Third order sensory neurons extend from the Thalamus to the Cerebral Cortex .

Where do synapses between the 2^nd order and 3^rd order neuron occur? In the Thalamus

Where are the cell bodies for the upper motor neurons located? The Cerebral Cortex

Where are the cell bodies of the lower motor neurons located? The Anterior Horn (Ventral) of Grey Matter; in the Spinal Cord

The axon of the lower motor neuron may leave by what? The Ventral Root

19. What may pain under the right shoulder indicate? (pg 523, Figure 14.8) Gall bladder Problems

What are the apparent causes for referred pain? The same spinal segments innervate both areas; we use the same nerves or they are very close to each other for the different things (areas)

20. List the 4 stages of Non-REM sleep. (pg 549)

Types and Stages of Sleep
Stage	EEG Pattern	Description	Vital Signs	Dream	If Stimulated	Muscles
1	Alpha waves	Eyes closed; thoughts flit in & out, drifting sensation; normal	Normal		Arousal is immediate	Relaxation begins
2	More irregular	Sleep Spindles – sudden, short high voltage wave bursts appear; 12 – 14 Hz			Arousal is more difficult
3	Theta & Delta waves	Sleep deepens; usually reached 20 minutes after stage 1	Begin to Decline	Common		Skeletal muscles very relaxed
4	Delta waves	Called Slow-wave sleep because of Delta waves dominate; bed-wetting & sleep walking may occur; also a restorative sleep	Lowest normal levels		Arousal is difficult	Skeletal muscles relaxed; normal turns every 20 min.; digestion increases
REM	Beta waves	EEG reverts through NREM stages to stage 1; lack of REM makes person moody & depressed	Increase	Most dreams occur		Skeletal muscles (except for ocular) are inhibited; Digestion activity declines

What is REM sleep? Rapid eye movement; dream sleep; restorative sleep

Cranial Nerves

21. List the names, numbers and functions of the 12 cranial nerves. (white Handout)

Cranial Nerves
#	Name	Function	Poem 1 (Old)	Poem 2	Nerve	Poem
1	Olfactory	smell	On	On	Sensory	Some
2	Optic	vision	Old	Occasion	Sensory	Say
3	Oculomotor	movement of eyelid & eyeball	Olympus	Our	Motor	Marry
4	Trochlear	movement of eyeball	Towering	Trusty	Motor	Money
5	Trigeminal	chewing	Tops	Truck	Both	But
6	Abducens	movement of eyeball	A	Acts	Motor	My
7	Facial	facial expressions	Finn	Funny	Both	Brother
8	Vestibulocochlear (Auditory)	hearing & equilibrium	And	Very	Sensory	Says
9	Glossopharyngeal	taste & swallowing	German	Good	Both	Bad
10	Vagus	lungs, esophagus, airways, heart, stomach, small intestine, most of large intestine, gallbladder	Viewed	Vehicles	Both	Business
11	Accessory (Spinal)	helps vagus	Some	Any	Motor	Marry
12	Hypglossal	swallowing	Hops	How	Motor	Money

22. The olfactory nerve enters the brain through what bone? The Cribiform Plate of the Ethmoid bone

What nerves have only sensory nerve cells? #1, 2, 8

What nerves have only motor nerve cells? # 3, 4, 6, 11, 12

What are the 3 cranial nerves that cause movement of the eyeball? Oculomotor/3, Trochlear/4, Abducens/6

What nerve allows chewing and sensory input from most of the face? Trigeminal, #5