The PNS and ANS Flashcards
The ________ is composed of nervous system structures outside the brain and spinal cord; nerves, ganglia, sensory receptors and efferent nerve endings.
PNS
A nerve is a cordlike organ composed of numerous nerve fibers (________) bound together by connective tissue.
axon
A nerve may contain a few nerve fibers or
hundreds of thousands
Spinal nerve axons are grouped within connective tissue, what are these 3 layers
endoneurium, perineurium, epineurium
delicate layer of loose connective tissue
endoneurium
connective tissues around the nerve fascicles
perineurium
whole nerve is surrounded by a tough fibrous sheath
epineurium
Are these nerves innervated with numerous blood vessels?
Yes
Peripheral nerves, either cranial or spinal, are classified according to the __________ in which they transmit impulses.
direction
Most nerves contain both sensory and motor fibers, these are called what
mixed nerves
transmitting sensory from the body to the brain, these are called
Sensory, or afferent, nerves
transmit signals from the brain to the muscles and glands, these are called
Motor, or efferent, nerves
Ganglia associated with afferent nerve fibers are cell bodies of _________ neurons
sensory
ganglia associated with efferent nerve fibers are mostly cell bodies of _________ motor neurons.
autonomic
what is the difference between the regeneration of PNS vs CNS nerve fibers
PNS: if cell body remains intact, axons can regen
CNS: no chance
so what cells help rebuild fibers / support them for each the PNS and CNS
PNS: schwann cells, help regen
CNS: oligodendrocytes, do not support regrowth
What do sensory receptors do?
collect info about the environment and send it to the brain
what are the ways to classify sensory receptors?
(a) stimulus modality
(b) origin of the stimulus
(c) dist of receptors in the body
what are some examples of the stimulus modality
thermoreceptors, photoreceptors, nociceptors, chemoreceptors, mechanoreceptors
respond to temperature changes
thermoreceptors
in the eye respond to light
photoreceptors
respond to harmful stimuli that result in pain
nociceptors
respond to chemicals in solution and changes in blood chemistry
chemoreceptors
respond to mechanical forces such as touch, pressure, stretch, and vibrations
mechanoreceptors
what are some examples of classifying by origin of stimulus
exteroceptors, interoceptors, proprioceptors
sensory end organ that responds to stimuli from the external world
exteroreceptors
Nerve ending situated in a visceral organ; responds to changes and stimuli within the body’s internal environment
interceptors
Receptor that senses moment in the musculoskeletal system; more specifically, proprioceptors sense stretch in muscles, tendons, and joint capsules
proprioceptors
give an example of distribution of receptors in the body
general (somatic) senses, special senses
touch, pain, pressure, temperature, and proprioception is that general or special?
general (somatic) senses
taste, vision, hearing, and equilibrium is that general or special?
special senses
Are general sense receptors complex or simple?
simple, one or a few sensory nerve fibers
on a mircoscoping level what can you see in a sensory receptor
free nerve ending, cilia, encapsulated nerve endings at the dendrites of a-order sensory neurons, or separate cells that synapse w/ 1st order sensory neurons
what are the nerve endings that are wrapped in glial cells or CT that are mechanoreceptors for touch, pressure, and stretch
encapsulated nerve endings
__________ sensations are : sense of touch
tactile
________ touch refers to : general, vague sense of touch (ie something made contact)
crude
_____ touch provides specific information about : details -> location, size, shape, and texture
fine
_________: sense of continuous mechanical force
pressure
________ : perception of rapidly oscillating stimuli
vibration
_______ Receptors: specialized structures in the skin and other tissues that respond to specific stimuli and initate nerve impulses to the brain
sensory
_______ nerve endings: detect pain, temp, and light touch (epidermis)
free
________ ______: sustained pressure and texture (epidermis), fine touch discrimation
merkel’s (tactile) discs
_____ _____ plexuses : detect movement of hair or light touch
hair root plexuses
__________ (lamellated) _________: deep pressure and vibration (dermis)
Pacinian (lamellated) corpuscles
___________ _________: continuous pressure and stretch
Ruffini’s corpuscle
___________ Sensations : bodys ability to sense its position, movement, and orientation in space, even without visual input
proprioceptive
what are the 3 proprioceptors
Pacinian corpuscles, muscle spindles, Golgi tendon organs
which proprioceptor is the speed of joint movement
Pacinian corpuscles
which proprioceptor is for muscle length and stretch
muscle spindles
which proprioceptor is tendon tension and force
golgi tendon organs
In addition to tactile, touch, pressure/vibration sensations and proprioceptive sensations, what is the last one?
temperature - detect changes in temperature
_______ is a vital sensation because it provides us with information about tissue-damaging stimuli and with signs that may be used for diagnosis of disease or injury.
Pain
___________: Pain receptors in the body that detect potentially harmful stimuli, triggering the sensation of pain to protect the body from injury
nociceptors
What are the 2 types of pain recognized by the parietal lobe of the cortex
somatic and visceral
what is the difference between somatic and visceral pain
- somatic (superficial and deep)
- visceral: felt just under the skin, overlying an organ (associated w/ referred pain)
T or F: Projection pathways for pain are diverse and complex, and the sensation can originate anywhere along any of the routes.
T
How many main pathways does pain have, but it also has multiple subroutes
2
Pain signals from the head travel to the brainstem by way of four cranial nerves:
trigeminal (V), facial (VII), glossopharyngeal (IX) and vagus (X)
Okay so these 4 from the head are 2nd order and arise at the medulla, where to next
thalamus > cerebral cortex
Pain signals from the neck down travel by way of three of the ascending spinal cord tracts:
spinothalamic tract, the spinorecticular tract, and the gracile fasciculus
These from the neck down, thalamus relays most pain signals through 3rd order neurons to their final destination of
postcentral gyrus of the cerebrum
_______ ________ : A phenomenon in which pain is perceived in a location different from the site of the actual injury or underlying problem
Referred pain
how many pairs of cranial nerves attach to the brain and innervate the head and neck
12
the ________ nerves are the only pair that “wanders” into the thorax and abdomen.
vagus
T or F: C. Some cranial nerves (I, II,) contain only sensory fibers and are called sensory nerves. The rest are mixed nerves because they contain both sensory and motor fibers.
True
In terms of cranial nerve pathways, most motor fibers of these nerves begin in nuclei of the brainstem and lead to
glands and muscles
Cranial nerve sensory fibers begin in receptors located mainly in the head and neck and lead mainly to the _________
brainstem
Should you know all the cranial nerves, roman numerals, and functions?
Yes
What is the pneumonic to memorize these
O O O TO TOUCH AND FEEL VERY GOOD VELVET AH
Fibers transmit impulses associated with detecting odors – smell.
Olfactory nerve (CN I)
T or F: If I is damaged, the sense of smell is impaired; it can be tested by determining whether a patient can sense aromatic substances.
True
Fibers transmit impulses associated with vision.
Optic nerve (CN II)
If damaged, _______ occurs in part or all of the visual field; it can be tested by inspecting the retina and testing peripheral vision and visual acuity.
blindness
This nerve has motor impulses to muscles (that control mvmt of eyeball up, down, medially), focus lens (accommodation), and adjusting light entering eye (pupil diameter)
oculomotor nerve (CN III)
What may be a sign that the oculomotor nerve has been damaged?
dropping eyelid, dilated pupil, inability to move eye / difficulty tracking objects
What nerve controls the superior oblique muscle that rotates the eye laterally and depresses it
trochlear nerve (CN IV)
what may a patient experience with a damaged trochlear nerve?
double vision, cant rotate eye laterally, tilt head towards affected side
The largest and most important sensory nerve of the face and has three divisions, what is this nerve
Trigeminal nerve (CN V)
What do three divisions allow for?
sensation fo the face and motor control of chewing muscles
What are the “3 sisters” of the trigeminal nerve (CN 5)
- ophthalmic division
- maxillary division
- mandibular division
C) If this nerve is damaged, sensation is lost from the UPPER FACE; it can be tested by evoking the corneal reflex (blink in response to light touch to eyeball).
opthalmic division
If it is damaged, sensation is lost from the MIDDLE of the FACE; test the sense of touch, pain, and temperature.
maxillary division
If it is damaged, the patient may have loss of sensation and impaired chewing; assess motor functions by palpating masseter and temporalis while subject clenches teeth and test ability to move mandible side to side and open mouth
Mandibular division
If it is damaged, the patient is not able to turn the eye laterally, and at rest the eye turns medially; test for lateral eye movement.
Abducens nerve (CN VI) -> motor impulses to lateral rectus
Mixed nerve: has sensory function in taste (2/3 of the tongue) and is the major motor nerve of the facial muscles.
facial nerve (CN VII)
What would be signs of damage to facial nerve
faical sagging due to loss of muscle and distorted taste especially for sweet things
Aka acoustic or auditory nerve, responsible for hearing and balance
vestibulocochlear nerve (CN VIII)
What are the two branches of the vestibulocochlear nerve (CN VIII)
- vestibular branch (associated with vertigo and ataxia)
- cochlear branch
If vestibulocochlear is damaged, the patient experiences nerve deafness, dizziness, nausea, loss of balance, and nystagmus (what is this?)
invol oscillation of eye side to side
Mixed nerve with numerous sensory and motor functions in the head, neck, and thoracic regions, primarily control the tongue and pharynx.
Glossopharyngeal nerve (CN IX)
If ____________ is damaged, a person has impaired swallowing and loss of bitter and sour tastes. Test for the gag reflex (lift throat during swallowing) , ability to swallow and cough, and note any speech impediments, also test posterior third of tongue with sour and bitter substances.
glossopharyngeal
Mixed parasympathetic nerve: has the most extensive distribution of any cranial nerve, supplying organs in the head, neck, and most viscera of the thoracic and abdominopelvic cavities.
Vagus nerve (CN X)
If it is damaged, a patient may exhibit hoarseness or loss of voice, impaired swallowing and gastrointestinal motility, and even _______ if both vagus nerves are damaged. Test palatal movement during speech, abnormalities of swallowing, weak, hoarse voice, and absence of gag reflex.
death
Primarily motor nerve: involved in head, neck, and shoulder actions, is unusual in that it does not arise entirely from the brain but in part from the cervical spinal cord. The pair has a relationship with the vagus nerves.
Accessory nerve (CN XI)
what are the 2 branches of the accessory nerve
a. cranial branch
b. spinal branch (SCM)
If it is damaged, a patient exhibits impaired movement of head, neck, and shoulders, difficulty shrugging on affected side, and paralysis of _______ causing the head to turn toward injured side; test ability to rotate head and shrug shoulders.
SCM
Motor terminates at muscles of the tongue when speaking and swallowing
Hypoglossal nerve (CN XII)
If it is damaged, speech and swallowing are impaired, with __________ of the tongue toward injured side, with atrophy, or an inability to protrude the tongue if both left and right nerves are damaged; test movement of tongue.
deviation
______ pairs of mixed spinal nerves arise from the spinal cord and serve the entire body except the head and neck
31
Each spinal nerve connects to the spinal cord by a _______ root, containing motor fibers, and a _______ root, containing sensory fibers.
ventral, motor
dorsal, sensory
All spinal nerves are mixed except for the
first pair
________ fibers connecting to the skin and skeletal muscles
somatic
_________ fibers connecting to viscera
autonomic
There are ___ pairs of cervical nerves, ____ pairs of thoracic nerves, ____ pairs of lumbar nerves, ___ pairs of sacral nerves, and ___ pair of coccygeal nerves.
8
12
5
5
1
Where does the first cervical spinal nerve emerge from
between skull and atlas (CI)
For cervical, the nerve corresponds to the # of the vertebra ________ them
above (nerve C5 emerges above vertebra C5)
Below the cervical vertebrae, the pattern changes. The remaining spinal nerves emerge inferiorly to the corresponding numbered vertebrae, give an example for L3
nerve L3 emerges inferior to vertebra L3
Spinal nerves are the ______ of ventral root and a dorsal root. Roots are the two points of attachment that connect each spinal nerve to a segment of the spinal cord
union
(a) The posterior or dorsal (sensory) root contains sensory nerve fibers and conducts nerve impulses from the periphery into the spinal cord; the dorsal root _________ contains the cell bodies of the sensory neurons from the periphery.
ganglion
The anterior or ventral (motor) root contains motor neuron axons and conducts impulses from the spinal cord to the _________
periphery
the cell bodies of motor neurons are located in the ______ matter of the cord.
gray
. The nerve then exits the vertebral canal through the ___________ foramen; the nerve is thus a mixed nerve.
intervertebral
1) Shortly after passing through its intervertebral foramen, a spinal nerve divides into several branches; these branches are known as _____
rami
T or F: Branches of a spinal nerve include the dorsal ramus, ventral ramus, meningeal branch, and communicating rami.
True
(1)The __________branch : arises from the spinal nerve shortly after it exits the intervertebral foramen, supplies the meninges and blood vessels in the spinal canal
meningeal
(2)The _______ (posterior) rami : branches of the spinal nerve that primarly serve the posterior (back) portion of the body (supply both sensory and motor fibers)
dorsal
(3) The _______ (anterior) rami : larger branches of the spinal nerve that primarly supply the front sides of the body, of the limbs and anterior trunk.
ventral
The ventral rami of spinal nerves, except for T2-T12, form networks of nerves called ________
plexuses
Emerging from the plexuses are _____ bearing names that are often descriptive of the general regions they supply or the course they take
nerves
(ii) The ventral (anterior) rami of spinal nerves T2-T12 do not enter into the formation of plexuses and are known as
intercostal or thoracic nerves
The ventral ramus also gives off a pair of communicating rami that connect with a string of ________ chain ganglia in spinal nerves T1 through L2.
sympathetic
Except in the _________ region, the ventral rami branch and merge to form five weblike nerve plexuses: the cervical plexus, brachial plexus, lumbar plexus, sacral plexus, and coccygeal plexus.
thoracic
(a) The ________ plexus : buried deep in the neck, under the SCM muscle, and extends into the posterior triangle of the neck
cervical
The cervical plexus supplies the : _________ nerve (__-___)
Phrenic nerve (C3-C5)
What does the phrenic nerve supply blood to and why is it important?
innervation to the most vital resp muscle (diaphragm), if cut, resp arrest will occur
The ______ plexus : lies partly in the neck and partly in the axilla and gives rise to almost all of the nerve that supply the upper limb
branchial
The brachial plexus gives rise to what 4 nerves of the arm
- musculocutaneous: C5-C7
- axillary: C5-C6
- radial: C5-T1
- ulnar and median: C5-T1
(d) The sacral and lumbar plexuses overlap and because many fibers of the lumbar plexus contribute to the sacral plexus via the lumbosacral trunk, the two plexuses are often referred to as the _________ plexus.
lumbosacral plexus
(1) The lumbar plexus (___-____) supplies the lower abdomen, pelvis, and anterior and medial parts of the lower limbs
Lumbar plexus (L1-L5)
what 2 nerves does the lumbar plexus supply
- femoral nerve: L2-L4
- Obturator nerve: L2-L4
The_______ plexus supplies the buttocks, perineum, and part of the lower extremities. It consists of the ventral rami of L4-L5 & S1-S4 and is located anterior to the sacrum.
sacral
(i) The largest nerve arising from the sacral plexus (and the largest nerve in the body) is the _______ nerve.
sciatic
- L4 to S3 supplies post thigh & all below _____
knee
________ pain extends from the buttock down the leg to the foot
sciatica
2 Sciatic Nerve Branches
- common peroneal (fibular) nerve (anterolateral aspect)
- tibial nerve (deep)
Each spinal nerve except C1 receives sensory input from a specific skin area called a _________
dermatome
____ successive spinal nerves must be anesthetized or severed to produce total loss of sensation from one dermatome.
3
The ________ nervous system is a system of motor neurons that innervate the smooth muscle, cardiac muscle, and glands of the body.
Autonomic nervous system (ANS)
does the ANS innervate SKM?
NO
The ANS is the ________ visceral motor division of the peripheral nervous system.
general
How is homeostasis maintained in the ANS
sensory afferent input from receptors in organs, and efferent motor output to the same effector organs
Structurally, the ANS includes
- autonomic sensory neurons
- integrating centers in the CNS
- autonomic motor neurons
Functionally, the ANS usually operates _______ conscious control.
WITHOUT
Its primary target organs are the _______ of the thoracic and abdominopelvic cavities and some structures of the body wall, including blood vessels, sweat glands, and piloerector muscles.
viscera
Visceral ________ do not depend on the ANS to function, but only to adjust their activity to changing needs
effectors
If ANS nerves to cardiac or smooth muscle are severed, the muscle exhibits _________ responses (denervation hypersensitivity).
exaggerated
The ANS is regulated by centers in the brain, mainly the ____________ and ________ ___________, which receive input from the limbic system and other regions of the cerebrum.
hypothalamus, medulla oblongata
As an example, high blood pressure activates a visceral baroreflex
baroreceptors sense an increase in BP in carotid arteries > transmit signals via glossopharyngeal nerve to MO > MO integrates info and sends signals via vagus nerve to heart > slow HR, reduce BP
The ANS has two subsystems: the ________ and the _____________ divisions.
sympathetic and parasympathetic
These two divisions often innervate the same target organs and have cooperative or contrasting effects. This is called _______ _________
dual innervation
The __________ division increases alertness, heart rate, blood pressure, pulmonary air flow, blood glucose concentration, and blood flow to muscles, while reducing blood flow to the skin and digestive tract. Fight or Flight
sympathetic
The _____________ division has a calming effect on many body functions. It is associated with reduced energy expenditure and normal bodily maintenance (resting and digesting). Rest & Digest
parasympathetic
Normally both systems are active __________, exhibiting a background rate of activity called autonomic tone that shifts from one to the other depending on the body’s changing needs.
simultaneously
T or F: Neither division has universally excitatory or calming effects.
True
The ANS includes control nuclei in the ___________ and other brainstem regions, motor neurons in the spinal cord and peripheral ganglia, and nerve fibers that travel through the cranial and spinal nerves
hypothalamus
What are the main ways that autonomic motor pathways differ from somatic motor pathways
- types of effectors
- # of motor neurons forming the pathway
- speed of impulses along fibers
- types of ganglia
- NT released
In ________ pathways, a motor neuron in the brainstem or spinal cord extends a myelinated axon all the way to a skeletal muscle.
somatic
In ___________ pathways, the signal must travel across two neurons to reach the target, a gland or smooth muscle cell, and must cross a synapse where these two neurons meet in an autonomic __________
autonomic
ganglion
autonomic: The first neuron, the __________ neuron: whose cell body is in the CNS
preganglionic
The _____________ neuron: whose cell body is an automatic ganglion
postganglionic
- Sympathetic responses are stimulated by the four E’s, what are they? The fight or flight response.
emergency, embarrassment, exercise, and excitement
The cell bodies of sympathetic preganglionic neurons are in the _______ gray horns of the 12 thoracic and first 2 or 3 lumbar segments. This division is called the thoracolumbar division.
lateral
Preganglionic fibers leave spinal nerves through _______communicating rami and enter the paravertebral ganglia (or sympathetic trunk or vertebral chain).
white
The postganglionic fibers, which are unmyelinated, leave the ganglion by way of the ____ communicating rami and extend to the target.
gray
T or F: There is no simple one-to-one relationship between preganglionic and postganglionic neurons in the sympathetic division. Both neural convergence and neural divergence are present.
True
After entering the sympathetic chain, preganglionic fibers may follow any of three courses.
- end in the ganglion and synapse immediately w/ a postganglionic neuron
- travel up/down the chain and synapse in ganglia at other levels
- pass thru the chain w/o synapsing and continue as splanchnic nerves
A single sympathetic preganglionic fiber has many axon collaterals and may synapse with 20 or more postganglionic neurons and therefore the effects of sympathetic stimulation are more ___________ than the effects of parasympathetic stimulation.
widespread
EXCEPTION: preganglionic fibers to adrenal medulla ___ ______ synapse with postganglionic neurons. Developmentally, the adrenal medulla is a modified sympathetic ganglion and its cells are similar to sympathetic postganglionic neurons.
do not
What are some examples of sympathetic responses
increase ATP prod, dilation of pupils, increase HR/BP, increase bf to skm, increase glycogenolysis, increase lipolysis (for E), shoot
The effects of parasympathetic stimulation last for a ________ time and are less widespread than those of the sympathetic stimulation.
shorter
Preganglionic cell bodies are found in cranial nerve nuclei (III, VII, IX, and X) in the midbrain, pons and medulla and lateral gray horns of the 2nd - 4th sacral segments of cord. __________ division
craniosacral division
- Their long preganglionic fibers end in terminal ganglia in or ____ the target organ.
near
There is much less neural __________ in the parasympathetic division than in the sympathetic division. Preganglionic neurons usually synapse with 4-5 postganglionic neurons at viscera.
divergence
The _______ nerve (CN X). This nerve carries about 90% of all parasympathetic preganglionic fibers. It travels down the neck and forms three networks in the mediastinum of the chest:
vagus
- cardiac plexus
- pulmonary plexus
- esophageal plexus
What is the parasympathetic, rest and digest response (think acronym)
salivation, lacrimation, urination, digestion, defecation “SLUDD”
What are some examples of parasympathetic responses
decreased HR, decreased airway diameter, decrease pupil diameter, point, conserve/restore body E, decrease body functions that support PA
The visceral division of the PNS contains sensory as well as motor (autonomic) neurons; general visceral sensory neurons monitor stretch, temperature, chemical changes, and irritation within the visceral organs; referred pain is _________, not somatic in origin.
visceral
________ reflexes such as defecation, micturition, erection, and ejaculation are integrated in the spinal cord.
Autonmatic
The brain can inhibit defecation and urination consciously, but if the spinal cord is severed, spinal reflexes _______ control these functions.
alone
In spite of its name, the ANS is not __________; all of its output comes from the CNS, and it is influenced by other levels of the nervous system.
NOT INDEPENDENT
The ____________ controls and integrates the autonomic nervous system. It is connected to both the sympathetic and the parasympathetic divisions
HYPOTHALAMUS
Hypothalamus regulates Autonomic _______ - a balance between the sympathetic and parasympathetic activity and visceral functions - body temperature, hunger, thirst, water and electrolyte balance.
tone
Output from the hypothalamus travels to nuclei in more caudal regions of the brainstem and from there to the cranial nerves and sympathetic neurons in the ______ _______
spinal cord
Control of the ANS by the CEREBRAL CORTEX occurs primarily during __________ stress such as anger, fear, desire, and so on.
emotional
The _______ ________ is involved in many emotional responses and has extensive connections with the hypothalamus. It thus provides a pathway connecting sensory and mental experiences with the autonomic nervous system.
limbic system
_______ _________ regulates HT signals regarding cardiac, vasomotor and respiratory activities.
medulla oblongata
The midbrain, pons, and medulla oblongata house numerous autonomic nuclei, of which many belong to the _________ ___________ which extends from the medulla to the hypothalamus.
reticular formation
