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Anatomy and Physiology Unit 3 Nerves


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What tissue groups does the Central Nervous System consist of?
Brain and Spinal Cord
What are the divisions of the Peripheral Nervous System?
Somatic & Autonomic
What is the Central Nervous System?
The portion which lies within the skull and vertebral column.
What is the Peripheral Nervous System?
It lies outside of the skull and vertebral column and includes the cranial and spinal nerves.
What is the Somatic system?
Part of the Peripheral Nervous System and supplies skeletal muscle and skin.
What is the Autonomic system?
Part of the Peripheral Nervous System and supplies smooth muscle, cardiac muscle and the various glands of the animal body. Most organs receive nerves from the two divisions of the Autonomic system to control their activities and maintain homeostasis.
What are the two divisons of the Autonomic system?
Parasympathetic division and Sympathetic division
What does the Parasympathetic division supply?
impulses to organs (tissues) that tend to maintain normal function and conserve body resources.
What does the Sympathetic division supply?
impulses that tend to cause an acceleration of processes that resist stress.
What are the three basic functions of the nervous system?
Sensory, Motor, and Integrative (anaylyze sensory information to make decisions)
What are the two principal kinds of cells in the nervous system?
Neuroglia and neurons
What percentage of neuroglia are there in the CNS?
How do neuroglia compare to neurons in size?
Neuroglia and smaller than neurons
Are neuroglia capable of dividing (mitosis) in the mature nervous system?
What can be derived from neuroglia?
Brain tumors (many are derived this way)
What are the six types of Neuroglia?
Astrocytes, Ologodendrocytes, Microglia, Ependymal, Neurolemmocytes, and Satellite
Which four types of neuroglia are found in the CNS?
Astrocytes, Ologodendrocytes, Microglia, Ependymal
participate in the metabolism of neurotransmitters, maintain potassium ion balance
most common, form a supporting network by wrapping around neurons
small phagocytic cells that protect the CNS
form CSF, line ventricles and central canal of cord
PNS in origin, produce myelin sheaths
support neurons (PNS) in ganglia
Why is the insulation of the axon important?
The conduction of the nerve impulse is more efficient; without it the electrical impulse going to the brain would "fizzle out" before reaching its primary destination.
How does the thinness of a nerve relate to insulation?
The thinner the wire the more necessary adequate insulation
What are neurons?
the excitable and conductible units of the nervous system
Can mature neurons divide?
No, They lack centrioles after adolescence so this suggests and inability to divide.
What are the two inclusion structures found only in neural cytoplasm?
Nissl Bodies and Neurofibrils
tiny hollow tubes, running through the entire cytoplam, which serves supporting and nurtitive functions
Nissl bodies
contain RNA. They have ribosomes associated with them and apparently synthesize the proteins that neurons use for structural and physiological mechanisms.
What are the two types of processes that the neural cell body gives rise to connect the cell body to other neurons via a synapse?
Dendrite and Axon
generally multiple, highly branched, relativelt short, which connect nerve impulses toward the cell body.
long, usually singular, sparsely branched and regular processes which conduct nerve impulses away from the cell body.
What is afferent?
Conducts impulses toward the CNS
What is efferent?
Conducts impulses away from the CNS
Internuncial neurons
(association) found between afferent and efferent neurons in the CNS
Myelin Sheath
a segmented fatty covering formed by glial cells (connective supportive, and nutritive components).
What produces myelin in the Peripheral nerve fibers?
the glial cells called Schwann cells
What does the myelin sheath do?
Increase the speed of impulse conduction
Term used to describe a process with a myelin sheath
Schwann Sheath-a thin membrane external to the myelin and consists of the cyoplasm and membranes of the Schwann cells
What does the neurilemma do?
aids in the regeneration of injured nerve fibers and components.
When does development of the CNS begin?
begins in the third week with the appearance of the neural plate.
What are the three primary vesiscles of the anterior portion of the nerual tube develop into?
Prosencephalon (forebrain), Mesencephalon (midbrain), and Rhombencephalon (hindbrain).
How much does the adult brain weigh?
2-3 pounds
The adult brain can be divided into what four principle parts?
Brain Stem, Cerebellum, Diencephalon (thalamus and hypothalamus), and Cerebrum (right and left halves)
What is one of the problems with aging on the CNS?
Continual loss of neurons
What senses decline as a result of aging?
Smell, vision, and hearing
What types of nerve receptors are associated with the skin?
Free nerve endings, Ruffini corpuscle, Meissner's corpuscle, Krause's bulb, Pacinian corpuscle, and Neuromuscular spindle
What skin nerve receptor is associated with cold?
Krause's bulb
What skin nerve receptor is associated with heat?
Ruffini corpuscle
What skin nerve receptor is associated with pain?
Free nerve endings
What skin nerve receptor is associated with pressure?
Pacinian corpuscle
What skin nerve receptor is associated with touch?
Meissner's corpuscle
What skin nerve receptor is associated with position tension?
Neruomuscular spindle
aortic body
One of the small bilateral structures, attached to a small branch of the aorta near its arch, and containing chemoreceptors that respond primarily to decreases in blood oxygen concentration.
carotid body
A chemoreceptor located near the bifurcations of the carotid arteries that monitors changes in the oxygen content of the blood and helps control respiratory activity.
What are the two basic properties of neurons?
Exciteability: ability to respond to stimuli
Conductivity: ability to transmit, as a nerve impulse, the disturbance resulting from the reaction to a stimulus
How does excitablity result?
From the seperation of ions on two sides of a semipermiable mebrane
What state is the term for the resting state in nerve conduction?
What state is the term for the active state in nerve conduction?
What is the rate of nerve conduction?
~100 meters/second
What is a synapses?
Juctions between neurons and conduct one-way and are areas of functional but not anatomical association
How does an impulse cross a synapse?
chemically by chemical transmitter substances.
Where are the chemical transmitter substances stored?
In the ends of the axon storage areas known as vesicles
So the chemical transmiiter does not continue to exert it effect in the synapse what is used?
An enzyme will inactivate the transmitter substance.
Where is ACh found and what enzyme is its inactivator?
Myoneural juction; peripheral synapses between neurons; brain stem; thalamus, and cerebral cortex.
Where is Norepinephrine found and what enzyme is its inactivator?
Autonomic system neurons, midbrain, pons, and medulla
Monamine oxidase (MAO)
Where is Seratonin found and what enzyme is its inactivator?
Hypothalamus, spinal cord

Where is Histamine found and what enzyme is its inactivator?

What does hypoxemia do to the synapse?
Low blood oxygen causes cessation of synaptic activity
What is fatigue of the synapse?
When transmitter substances are used up faster than it can be produced which results in the slowing or even stopping of tranmission
What are the five parts of a Reflex Arc?
Receptor, Affernt neuron, CNS synapse, Efferent neuron, and effector
Can peripheral nerve fibers regenerate?
Yes they may
Can CNS nerve fibers regenerate?
Little to none
largest portion of the brain in mammals, what is traditionally thought of as the brain
What divides the cerebrum into right and left halves?
Longitudinal Fissure
Gyri or gyrus
Folds of the Cerebral cortex
Sulci or sulcus
The grooves between the folds
What divides the frontal and parietal lobes?
The central sulcus or the Fissure of Rolando
What divides the temporal from the frontal and parietal?
The lateral sulcus or the Fissure of Sylvius
At what age of development does the rolling of the brain occur?
8 months as a fetus and into the newborn baby
What are the basic functions of the cerebrum?
Perform all functions above consciousness, Memory, Foresight, Emotions, Sight and hearing, and Speech
Second largest part of the brain
What seperates the cerebellum from the cerebrum?
The transverse fissure
What is the exterior of the cerebellum composed of?
gray matter
What is the interior of the cerebellum composed of?
white matter
Is the cerebellum grooves with sulci like the cerebrum?
What are the two large lateral masses of the cerebellum?
cerebellar hemispheres and a central section calld the vermis
What is the internal white matter of the cerebellum composed of?
Some short and some long tracts
What do the short association tracts of the cerebellum do?
Connect the cerebullar cortex with nuclei located in the interior
What do the long projection tracts of the cerebellum do?
Connect the cerebellum with other parts of the brain and with the spinal cord
What are the three lobes of the cerebellum?
Flocculonode, Neocerebellum, and Paleocerebellum
What function does the Flocculonode have?
aids in equilibrium, controls motion sickness
What function does the Neocerebellum have?
coordinates the eye and the ear
What function does the Paleocerebellum have?
damage to this area causes erratic movement and dysmetria (inability to judge distance in picking up an object).
Multimucleated (several centers), acts as a relay station for sensory impulses on their way from the periphery to the somatic sensory area of the cerbal cortex.
Which part of the brain plays a part in the arousal and alerting mechanism?
Which part of the brain associates sensory impulses with feelings of pleasantness or unpleasantness?
What are the functions of the hypothalamus?
monitor many physiological parameters such as pH, osmotic pressure and glucose levels. Body Temperature
What are the hormones produced by the hypothalamus?
ADH and oxytocin
What hormones does the hypothalamus regulate?
regulates hormone released by the neurohypophysis and signals the relases of adenohypophysial hormones by RF
What part of the brain is the coordinating center for ANS?
What part of the brain maintains water balance?
What part of the brain has the appetite and satiety centers?
What part of the brain maintains the waking state?
Which cranial nerve is number I?
Which cranial nerve is number II?
Which cranial nerve is number III?
Which cranial nerve is number IV?
Which cranial nerve is number V?
Which cranial nerve is number VI?
Which cranial nerve is number VII?
Which cranial nerve is number VIII?
Which cranial nerve is number IX?
Which cranial nerve is number X?
Which cranial nerve is number XI?
Which cranial nerve is number XII?
What is the origin of Cranial Nerve I?
What is the origin of Cranial Nerve II?
What is the origin of Cranial Nerve III?
What is the origin of Cranial Nerve IV?
What is the origin of Cranial Nerve V?
What is the origin of Cranial Nerve VI?
What is the origin of Cranial Nerve VII?
What is the origin of Cranial Nerve VIII?
What is the origin of Cranial Nerve IX?
What is the origin of Cranial Nerve X?
What is the origin of Cranial Nerve XI?
What is the origin of Cranial Nerve XII?
What is the inability to speak termed?
What is agraphia?
Inability to write
Is the spinal cord part of the somatic nervous system?
Are parasympethetic and sympethetic divisions of the ANS Antagonistic?
Are neuroglia smaller than neurons?
Are neuroglia capable of mitosis?
Which direction to dendrites conduct impulses?
Toward the body cell.
What unites the cerebral hemispheres on the inferior surface?
The corpus callosum
The central sulcus is also known as what?
The Fissure of Rolando
The cerebrum is divided into right and left halves by what fissure?
The longitudinal Fissure
Who developed the EEG?
What part of the brain acts as a relay station?
What is the second largest part of the brain?
The cerebellum
What is the function of 3,1,2 of Brodmann's Area?
General sensory area
What is the function of 17 of Brodmann's Area?
Primary visual area
What is the function of 18,19 of Brodmann's Area?
Secondary visual area
What is the function of 41, 42 of Brodmann's Area?
Primary auditory
What is the function of 44, 45 of Brodmann's Area?
Broca's motor speech area
What is the function of 6 of Brodmann's Area?
Secondary motor area
What is the function of 4 of Brodmann's Area?
Primary motor area
What part of the brain coordinates the eye and ear?
What part of the brain regulates body temperature?
What part of the brain regulates emotions?
What part of the brain is the site of TSH RF production?
What part of the brain is the site of vital centers?
What part of the brain has auxillary respiratory functions?
What part of the brain is the site of TSH production?
What part of the brain controls pupillary reflexes and eye movements?
What part of th brain is the site of ADH production?
What part of the brain is the site of TSH function
What is the pituitary gland also know as?
the Hypophysis
Which will transmit faster, a smaller nerve fiber ot a larger nerve fiber?
The larger nerve fiber will transmit faster
What must an individual already have has in order to experience shingles?
Chicken pox
The virus that causes fever blisters on the lip has an affinity for what nerve and its branches?
The Trigeminal
Does man, among mammals, have the "best" hearing, coordination and head-eye control?
Does man, among mammals, have the most advanced Broca's Area?
What is anti-pyogenic?
Any material that lowers body temperature
Can the human adult replace cerebral "higher Center" cells by mitosis?
Does the brain store large amounts of glucose?
What is a "mild stroke"?
A blood clot blockage occurs in the brain in an area that does not cut of blood supply to vital areas or higher centers so the damage that occurs is minimal or "mild".
What is a "massive" stroke?
A blood clot or blockage causes many Higher centers or vital areas of the brain to be blocked off from the blood supply and therefore oxygen permanemently causing damage to those centers that cannot be fixed.
What is the "Circle of Willis"?
A series of arteries that forms a ring on the ventral surface of the brain around the hypophysial stalk and serves to provide a connection between the major arteries to the brain.
What is another name for the "circle of Willis"?
Cerebral Arterial Circle
How does the hypothalamus regulate water balance?
When the hypothalamus senses increased blood concentration (blood is thicker) the hypothalamus responds by secreting ADH which goes to the kidneys and causes them to conserve water by decreasing the water that is excreted in urine.
What are four hormones synthesized and released by the adenohypophysis?
What does the basial ganglia do?
As a group control muscle tone, inhibit movement and control tremor.
How many pairs of cranial nerves are there?
12 pairs
What part of the brain attaches to the spinal cord?
What is the blood brain barrier?
Semipermiable membrane restricting molecules from passage into the CSF.
What function does the Cerebral Spinal Fluid have?
Acts as a shock absorber for the bnrain and cord and helps to compensate for drastic changes in the blood volume.
What is the daily volume of CSF produced?
500 mL
If a persons CSF were drained at any one time, how much would be in the body?
150-250 mL
What is the caudal end of the spinal cord called?
conus medullaris
What are the fine nerves at the caudal end of the spinal cord termed?
caudaul equine or spinal horse hair
How many spinal nerve pairs are there?
31 pairs
What are the three membranes that surround the spinal cord and brain collectively called?
What is the outer memmbrane of the meninges called?
dura mater
What is the middle membrane of the meninges called?
What is the inner membrane of the meninges called?
pia mater
What is the greatest diamter of the spinal cord itself?
It does not exceed 3/4 of an inch.
Where do receptors for smelling occur?
In the olfactory epithelium of the nasal cavities
What does odor classification depend on?
Molecule shape
What is the pathway for smell?
Olfactory cells to olfactory bulb to olfactory tracts to frontal and temporal lobes
What kind of sense is smelling?
A chemical sense
Where do receptors for taste occur?
primarily on the tongue
What are the four basic taste sensations?
Sour, bitter, salty, and sweet
How are sour tastes produced?
by H ions or acids
How are bitter tastes produced?
caused by alkaloids such as quinine and caffeine as well as many long chain organic molecules
How are salty tastes produced?
By Na+, NH4+, Ca++ and K+
How are sweet tastes produced?
the presence of compounds containing OH- groups
What is the eye?
What eye muscle moves the eyeball out?
Lateral rectus
Wht eye muscle moves the eyeball in?
Medial rectus
What eye muscle moves the eyeball up and in?
Superior rectus
What eye muscle moves the eyeball Down and in?
Inferior rectus
What eye muscle moves the eyeball Up and out?
Inferior oblique
What eye muscle moves the eyeball Down and out?
Superior oblique
What three tissue layers is the eye composed of?
Sclera, Uvea, Retina
What is the sclera?
outer most coat of the eye; posteriorly it is opaque and forms the "white of the eye" Anteriorly it is clear and forms the cornea.
What is the Uvea?
Middle coat od the eye; anteriorly, it consists of the cilliary body, including the ciliary muscle, iris, lens and lens ligaments. Posteriorly it is composed of the vascular choroid.
What is the retina?
inntermost layer of the eye, extends only as far anteriorly as the posterior border of the iris. It contains the rods and cones which are the visual receptors of the eye. Its nerve fibers are made of the same neurons as the optic nerves, thus the retina is actually just an evagination of neural tissue.
What is aqueous humor?
watery material that fills the portion of the eye anterior to the lens.
What secretes aqueous humor?
ciliary body
What drains the humor for the anterior chamber?
A ring of veins known as the canal of Schlemm
What results from a blockage of the canal that drains the humor?
Glaucoma because interocular pressure is raised higher than normal
What is the normal interocular pressure for the anterior portion of the eyeball?
15-20 mmHg
What is the rest of the eyeball filled with that serves tto maintain the eyeball shape?
vitreous humor
Why do people have a "blind spot"?
blood vessels that are responsible for eye nourishment enter the eyeball from behind the optic disc which is where the optic nerve leaves the eye and is void or visual receptors.
What does the lacrimal gland do?
secretes tear composed of antibiotic emzymes.
Where is the lacrimal gland located?
in the optic orbit, above and to the lateral side of the eye
What is Emmetropic vision?
Normal vision -focuses inverted image directly on the retina
What is Myopic vision?
Nearsighted-focuses images in front of the retina, because the eyeball is too long for refracting power of the eye
What is Hypermetropic vison?
Farsighted-also called hyperopia-focuses images behind the retina because the eyeball is too short for the refracting power of the eye.
What is an Astigmatism?
This occurs when the cornea or lens is shaped mroe like a teaspoon instead of having the same curvature vertically and horizontally. The unequal curtvature cause two seperate focal points and double vision.
What is Strabismus?
Cross-eye; result of improper convergence of the image on the retina
What is a Cataract?
lens clouds and there is a failure to transmit light rays to the retina
What is color blindness?
hereditary; lack of specific cones in the retina will result in red, green or blue color blindness
What part of the body does one hear with?
The brain
What function does the outer ear serve?
Gathers sound waves and conducts these sound waves to the tympanic membrane
What function does the middle ear serve?
Transmits tympanic vibrations via the malleus, incus, and stapes (the ossicles) They increase and decreas pressure of the stapes on the oval window of the cochlea.
What does the middle ear contain?
conists of middle ear cavity, ossicles and Eustachian tube
What does the inner ear contain?
Contains the cochlea (organ of hearing) and the structures associated with balance and equilibrium
What are the semicircular canals?
Three fluid-filled channels in each ear. Movement of fluid in these cannals trigger nerve impulses that allow fir proper orientaion of the head position. The canals detect motion and initiate motor responses via the cerebellum to maintain posture.
What is transmission deafness?
Occurs when sound waves are not allows to reach the tympanic membrane or by failure of the ossicles to transmit sound waves to the cochlea.
What are some causes of hearing loss?
Inflammation of the middle ear, fusion of the ossicles or fixation of the stapes in the oval window, wax collection, and ruptured tympanic membrane
What causes motion sickness?
Repetitive changes in angular and linerar acceleration affecting the receptors. The brain controls excessive movement of fluid by inducing nausea and vomiting.
What can cause a loss of equilibrium?
Infection of or damage to the vestibular nerve
What is Lou Gehrig's Disease?
Also known as ALS- progressive destruction of the anterior horm motor neurons and fibers of the pyramidal tract. Person losses ability to speak, swallow, and breathe.
What is Cerebral Palsy?
neuromuscular disability in which muscles are poorly controlled or paralyzed as a result of brain damage. Deficit is nonreverible and is single laregest cause of crippling in children
What is Huntington's Disease?
hereditary disorder that leads to massive degeneration of the basal nuclei and later of the cerebral cortex. Progressive and usually fatal within 15 yeats of onset
What is Parkinson's Disease?
Results from inadequate dopamine release by the substantia nigra. General symptoms include tremor, shuffling gait, lack of facial expression
What is Alzheimer's Disease?
progressive degenerative disease of the brain that ultimately results in mental deterioration and death.
What is a concussion?
bruising caused by intense jarring, shaking or blunt trauma.
What is a CVA?
Cerebrovascular Accident-
A stroke; occurs when blood circulation to a brain area is blocked and brain tissue in that area ceases to function.
What is ischemia?
The deprivation of blood to any tissue
What is TIA?
Transient Ischemic Attack-temprary numbness, paralysis and impaired speech occurring because of a blood clot that soon disintegrates.
How many of the brain's nerve cells does the cortex contain?
12-15 billion
What cranial nerves exite through the jugular foramen?
What spaces of the cerebrun is CSF produced?
the Choroid plexus
What artery gives rise to the posterio cerebellar artery?
The internal carotid

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