Module 13 V1 - Flashcards
What is the FUNCTION of the VISCERAL NERVOUS SYSTEM?
Maintain homeostasis within the body by controlling the functions of the:
- internal organs
- blood vessels
- ertain structures in the skin.
The visceral nervous system has both sensory & motor components.
A. True
B. False
TRUE
Explain the function of VISCEROSENSORY NEURONS
- Carry sensory information from the internal organs.
- This info is processed and used predominantly without conscious awareness.
What are the two divisions of the viscerosensory system?
- Sympathetic division
- Parasympathetic division
Explain the FUNCTION of the SYMPATHETIC division of the viscerosensory system.
- Carries info from nociceptors located in:
i. heart
ii. respiratory structures
iii. gastrointestinal tracts
iv. urogenital tracts. - This information is used to mediate reflexes at the level of the spinal cord and it is conveyed to brain regions via the ALS.
Explain the FUNCTION of the PARASYMPATHETIC division of the viscerosensory system.
- Carries information from physiological receptors that convey
innocuous stimuli and monitor the functions of visceral structures (mediation of reflexes will be most important) - and this information is CARRIED ON cranial nerves
- and PROCESSED BY the solitary nucleus or on pelvic nerves
- and PROCESSED AT the level of the spinal cord
- and CONVEYED TO brain regions via the ALS.
A _______ receptor is a type of physiological receptor. (Hint: think mechanic)
Mechanoreceptor.
Mechanoreceptors can be _______ or _______ adapting. (Hint: think speed)
Rapid adapting or slow adapting
Rapid adapting mechanoreceptors fire when …
a stimulus is applied and stop firing with sustained stimulation.
Rapid adapting mechanoreceptors are well suited to signal …
movement or sudden changes in pressure.
Rapid adapting mechanoreceptors are located in …
thoracic, abdominal, and pelvic organs
Slowly adapting mechanoreceptors will continue to fire …
in the presence of a stimulus.
Visceral pain is generally poorly localized and often referred to a somatic body part.
A. True
B. False
True
Explain the steps in which visceral pain is referred to a somatic body part. (Hint: 5 steps from organ to cortex)
- Visceral afferents from the organ join somatic afferents in the spinal nerve.
- Information at the spinal cord is where the cross-talk occurs between the two afferents, in which the visceral afferent activates the somatic dorsal horn cell.
- Fibers enter the anterior right commissure & travel to the cortex through the ALS (anterolateral system)
- Fibers contact another neuron in the chain of communication.
- Information is conveyed to the cortex.
Identify where the visceral pain from the organ would manifest on the somatic body part for the following examples:
A. heart disease
B. gall bladder disease
C. pancreatic disease
A. Heart disease = chest wall or arm
B. Gall bladder disease = back or between scapulae
C. Pancreatic diseases = back
Lecture Video Question 1
The sympathetic division of the viscerosensory system conveys innocuous information from the viscera.
A. True
B. False
B. False
Explanation:
This statement is false: the sympathetic division of the viscerosensory system conveys pain information and the parasympathetic division conveys innocuous sensory information (e.g., stretch/tension in hollow organs contributing to the sense of fullness; blood composition).
Lecture Video Question 2
Visceral pain is poorly localized and often referred to along a dermatome of the somatic nervous system secondary to “cross talk” between the visceral and somatic sensory systems.
A. True
B. False
A. True
Explanation:
This statement is true: visceral pain is poorly localized because of low receptor density and the large receptive fields of viscerosensory neurons, and because there is a small area of the cortex processing visceral sensory information (in comparison to somatosensory information). Sympathetic viscerosensory neurons travel in spinal nerves and often contact somatic dorsal horn cells. This “cross talk” results in visceral pain being interpreted as coming from the dermatome supplied by that spinal cord segment.
Visceromotor neurons control _______, _______, _______, and these components are often referred to as the autonomic nervous system. (Hint: 2 muscles and 1 gland)
A. smooth muscle
B. cardiac muscle
C. secretory glands
Innervation of structures of the head & body requires _______ from the _______ & _______ divisions, and outflow produces _______ results.
A. dual innvervation
B. parasympathethic
C. sympathetic
D. opposing results
Provide an example of opposing results from outflow between the parasympathetic and sympathetic divisions.
Parasympathetic outflow = pupillary constriction
Sympathetic outflow = pupillary dilation.
Innervation of structures of the body wall and limbs (i.e., blood vessels supplying skeletal muscles and skin, sweat glands, and the arrector pili muscles) are regulated by the _______.
sympathetic system
Communication in the ANS involves which 2 neurons?
- preganglionic neuron
- postganglionic neuron
For PREGANGLIONIC NEURONS, where is the cell body located and where do the axons of these neurons project?
Cell bodies located in either BRAINSTEM or SPINAL CORD.
Axons will project to an AUTONOMIC GANGLION.
For POST GANGLIONIC NEURONS, where is the cel body located and where do these axons project?
Cell bodies located in AUTONOMIC GANGLION.
Axons will project to VISCERAL TARGETS (ie. smooth muscle, cardiac muscle cells).
STRUCTURAL COMPARISON OF DIVISIONS
Where do the preganglionic cells originate for the sympathetic and parasympathetic divisions?
Preganglionic cells originate in the…
Sympathetic:
Intermediolateral cell column (T1 - L2) lateral horn cells
Parasympathetic:
cranial visceromotor nuclei (cranial outflow) and S2 - S4 (sacral outflow) spinal segments.
Cranial visceromotor nuclei include: Edinger Westphal nuclei, inferior & superior salivatory nuclei, & dorsal motor vagal nuclei.
STRUCTURE COMPARISON OF DIVISIONS
Where are the postganglionic neurons located for the sympathetic and parasympathetic divisions?
Postganglionic neurons are located in the…
Sympathetic:
Sympathetic chain of ganglia or prevertebral ganglia (near abdominal/pelvic arteries)
Parasympathetic:
Ganglia in the head region & intramural ganglia (near/in organs).
Ganglia head region includes: ciliary ganglion, pterygopalatine ganglion, submandibular ganglion, & otic ganglion
STRUCTURE COMPARISON OF DIVISIONS
What are the neurotransmitters for the sympathetic and parasympathetic divisions?
Neurotransmitters are:
Sympathetic:
Acetylcholine (pre-ganglionic) & norepinephrine (post-ganglionic)
Parasympathetic:
Acetylcholine (pre & postganglionic)
Outline the steps of sympathetic outflow.
- PREGANGLIONIC cells from interomedial cell column (T1-L2) using neurotransmitter acetylcholine project to…
- POSTGANGLIONIC neurons in the sympathetic chain of ganglia or prevertebral ganglia (near abdominal/pelvic arteries, which then use the neurotransmitter norepinephrine to communicate to…
- Target cells (smooth muscle).
Outline the steps for parasympathetic flow.
- PREGANGLIONIC neurons in cranial visceromotor nuclei (cranial outflow) and S2 - S4 (sacral outflow) communicate using neurotransmitter acetylcholine to…
- POSTGANGLIONIC neurons in ganglia of head region and intramural ganglia (near organs) use acetylcholine to communicate
FUNCTIONAL COMPARISON OF DIVISIONS
What is the difference between the effect on heart rate for the sympathetic and parasympathetic divisions?
Sympathetic:
INCREASE heart rate, blood pressure, blood flow to skeletal muscles, and blood glucose level.
Parasympathetic:
DECREASE heart rate
FUNCTIONAL COMPARISON OF DIVISIONS
What is the difference between the effect on the gut and blood flow in the area for the sympathetic and parasympathetic divisions?
Sympathetic:
DECREASE gut motility, digestive glandular secretion, and blood flow to viscera and skin.
Parasympathetic:
INCREASE digestive glandular secretion, blood flow to the gut & motility of the gut.
FUNCTIONAL COMPARISON OF DIVISIONS
What is the difference between the effect on the pupils and bronchiole for the sympathetic and parasympathetic divisions?
Sympathetic:
DILATION of pupil and bronchiole, sweating, and piloerection (hair standing).
Parasympathetic:
CONSTRICTION of the pupil and bronchiole, and accommodation of the lens of the eye.
Explain what HORNER SYNDROME is.
INTERRUPTION of the pathway through the SUPERIOR CERVICAL GANGLION results in horner syndrome.
Explain the pathway sequence for HORNER SYNDROME.
- Preganglionic sympathetic visceral motor neuron at the level of T1. This axon enters the sympathetic chain of ganglia.
- Ascends to postganglionic neuron and project to the superior cervical ganglia.
- Post ganglion will innervate target tissue in the eye and face.
What are the signs of HORNER SYNDROME?
On the affected eye you will see the following if a person were placed under a heat lamp:
- Miosis : constriction of the pupil
- Ptosis: drooping of the upper eyelid
- Flushing of the face
- Anhidrosis : diminished or absence of sweating because of loss of sympathetic innervation of the sweat glands.
HORNERS SYNDROME
Would you see damage ipsilateral or contralateral to the injury?
Ipsilateral
What are the different signs between Oculomotor Nerve Palsy and Horner Syndrome?
Oculomotor Nerve Palsy:
dilated pupil and pstosis (drooping of upper eyelid)
Horner Syndrome:
miosis and pstosis (drooping of upper eyelid)
Central Control of ANS
Visceromotor pathways operate locally at the level of the ________ and ________ (aka reflexes) and are influenced by a variety of “higher centers” collectively called the ________.
A. spinal cord
B. brainstem
C. central autonomic network
Central Control of ANS
Which parts are responsible for the SHORT TERM REGULATION of the ANS (ie. heart rate & blood pressure during changes in body position)?
A. Central Autonomic Network
B. Spinal cord
C. Brainstem
D. B & C
D. spinal cord & brainstem (medulla plays a key role) reflexes
Central Control of ANS
Which parts are responsible for the REGULATION of COMPLEX RESPONSES of the ANS (ie. elevated heart rate & blood pressure related to anxiety)?
A. Central Autonomic Network
B. Spinal cord
C. Brainstem
D. B & C
A. Central Autonomic Network
Central Control of ANS
What brain region is the highest integrator of autonomic and endocrine functions?
A. Hippocampus
B. Cerebrum
C. Hypothalamus
D. Amygdala
C. Hypothalamus
Central Control of ANS
The hypothalamus has reciprocal connections with which of the following? Select all that apply.
A. Limbic system
B. Solitary nucleus
C. Basal nuclei
D. B & C
A. Limbic system
B. Solitary nucelus
Central Control of ANS
The hypothalamus projects directly onto which of the following? Select all that apply.
A. pregangiolic neurons in the dorsal motor vagal nucleus (DMVN)
B. neurons in the anterolateral medulla
C. intermediolateral cell column (IMLCC) of the spinal cord
D. neurons in the posterolateral medulla
A. pregangiolic neurons in the dorsal motor vagal nucleus (DMVN)
B. neurons in the anterolateral medulla
C. intermediolateral cell column (IMLCC) of the spinal cord
Control of the ANS
Match the following:
- dorsal motor vagal nucleus (DMVN)
- intermediolateral cell column (IMLCC)
A. parasympathetic outflow
B. sympathetic outflow
- DMNV = parasympathetic outflow
- IMLCC = sympathetic outflow
LECTURE VIDEO QUESTION 3
The blood vessels of the skin and skeletal muscles of the body wall and limbs are innervated by only the sympathetic division of the ANS.
A. True
B. False
A. True
Explanation:
This statement is true: Innervation of structures of the body wall and limbs (i.e., blood vessels supplying skeletal muscles and skin, sweat glands, and the arrector pili muscles) are regulated by the sympathetic system only; smooth muscle, cardiac muscles, and glands of the head and body receive dual innervation from both divisions that produce opposing results.
LECTURE VIDEO QUESTION 4
Which of the following statements correctly describes the structural components of the parasympathetic division of the ANS? Select all that apply.
A. Preganglionic neurons are located in cranial visceromotor nuclei & at sacral levels of the spinal cord.
B. Preganglionic neurons are located in the intermediolateral cell column at the levels of T1-L2.
C. Post-ganglionic neurons are located in ganglia in the head region and intramural ganglia.
D. Post-ganglionic neurons are located in the sympathetic chain of ganglia.
E. Acetylcholine is the neurotransmitter that allows communication between the pre and postganglionic neurons, as well as between the postganglionic neurons and the target tissue.
A. Preganglionic neurons are located in cranial visceromotor nuclei & at sacral levels of the spinal cord.
C. Post-ganglionic neurons are located in ganglia in the head region and intramural ganglia.
E. Acetylcholine is the neurotransmitter that allows communication between the pre and postganglionic neurons, as well as between the postganglionic neurons and the target tissue.
Explanation:
The preganglionic neurons of the parasympathetic division are found in the cranial visceromotor nuclei (cranial outflow) & S2 – S4 (sacral outflow) spinal segments. The post-ganglionic neurons are located in ganglia in the head region and intramural ganglia (near organs), an the neurotransmitter that allows communication to take place between the neurons and between the neuron and the target tissue is acetylcholine. The preganglionic neurons of the sympathetic division originate in the intermediolateral cell column (T1-L2) and the post-ganglionic neurons are located in the sympathetic chain of ganglia or prevertebral ganglia (near abdominal/pelvic arteries). Acetylcholine is the neurotransmitter that allows communication between the neurons and norepinephrine is the transmitter that allows communication between the post-ganglionic cell and the target tissue.
LECTURE VIDEO QUESTION 5
Your patient sustained a neck injury that damaged the right superior cervical ganglion. You anticipate seeing which of the following clinical signs. Select all that apply.
A. left facial flushing
B. right facial flushing
C. right ptosis
D. right pupil constriction
E. left anhidrosis
B. right facial flushing
C. right ptosis
D. right pupil constriction
Explanation:
Damage to the right superior cervical ganglion reduces sympathetic outflow to the structures of the head/face: this will result in an ipsilateral Horner syndrome: right pupillary constriction (unopposed parasympathetic outflow), right ptosis (weak/paralyzed superior tarsal muscle); right facial flushing (loss of vascular tone); and absence of sweating on the right side (loss of innervation of sweat glands).
MICTURITION REFLEX
What is the micturition reflex?
Emptying of the urinary bladder.
MICTURITION REFLEX
Fill in the blanks with RELAXATION or CONTRACTION:
- ________ of the detrusor muscle (smooth muscle of bladder wall) mediated by the parasympathetic outflow.
- ________ of the smooth muscle of the INTERNAL URETHRAL SPHINCTER mediated by parasympathetic outflow.
- ________ of the skeletal muscle of the EXTERNAL URETHRAL SPHINCTER - mediated by the somatic motor system (S3-S4 PUDENDAL NERVE).
- contraction
- relaxation
- relaxation
