Autonomic Reflex Arc Flashcards
Preganglionic nerve fibers in the sympathetic nervous system are:
Study on!!!
The autonomic nervous system is a complex and well-coordinated network of —– arcs
visceral reflex arcs
The autonomic nervous system is a complex and well-coordinated network of visceral reflex arcs that work in concert to maintain whole-body —–.
homeostasis
Additionally, these reflex arcs are tightly integrated with the —– system
endocrine system
Additionally, these reflex arcs are tightly integrated with the endocrine system. The key points of integration include the —– axis
Renin-Angiotensin-Aldosterone axis
Additionally, these reflex arcs are tightly integrated with the endocrine system. The key points of integration include the renin-angiotensin-aldosterone axis as well as regulation of…
antidiuretic hormone,
mineralocorticoids,
glucocorticoids, and
insulin
The reflex arc allows for fine adjustments by —– and —– feedback mechanisms
positive and negative feedback mechanisms
What are the 5 major components of the Autonomic Reflex Arc?
- Sensor
- Afferent pathway
- Control center
- Efferent pathway
- Effector organ
*You may want to remember the mnemonic —– to remember the order of afferent and efferent pathways.
“ACE”
(Afferent - Control - Efferent)
—– monitor the environment and informs the CNS of changes within the environment
Sensors
When a change occurs, the stimulus alters the —– of the sensor.
Electrical potential
When a change occurs, the stimulus alters the electrical potential of the sensor. Next, the sensor transduces the stimulus into an —–.
Action potential
The —– pathway links the sensor to the control center
Afferent pathway
Afferent Pathway conducts the action potential towards the —–.
CNS
Which 3 Control Centers receive the bulk of sensory input from the body?
Hypothalamus, Brainstem, and Spinal cord
The cerebral cortex is —— of the autonomic reflex arc per se
Not a component
While the cerebral cortex is not a component of the autonomic reflex arc per se, it can modulate autonomic output that may occur with —–.
emotions
While the cerebral cortex is not a component of the autonomic reflex arc per se, it can modulate autonomic output that may occur with emotions, such as with —– and —–.
fear and anxiety
The —– pathway links the control center to the effector organ
efferent pathway
The efferent pathway conducts the —– towards the effector organ
action potential
The efferent pathway almost always consists of two nerve fibers:
1 preganglionic nerve, and
1 postganglionic nerve
The —– is the site where the preganglionic nerve and the postganglionic nerve form a synapse
ganglion
The preganglionic neuron is a —– fiber
myelinated B-fiber
The preganglionic neuron exits the CNS and synapses with the —– fiber
postganglionic fiber
The preganglionic neuron exits the CNS and synapses with the postganglionic fiber in an —– ganglion
autonomic ganglion
The preganglionic neuron releases —–.
acetylcholine
The preganglionic neuron releases acetylcholine onto a —– receptor
nicotinic type-N receptor
The preganglionic neuron releases acetylcholine onto a nicotinic type-N receptor in the —–.
ganglion
The postganglionic neuron is —– fiber
an unmyelinated C-fiber
The postganglionic neuron exits the ganglion and innervates the —– organ
effector organ
In the PNS, the postganglionic neuron is a —– postganglionic fiber
cholinergic postganglionic fiber
In the SNS, the postganglionic neuron is a —– postganglionic fiber
adrenergic postganglionic fiber
In the PNS, a cholinergic postganglionic fiber releases —– onto its effector organ
acetylcholine
In the SNS, an adrenergic postganglionic fiber releases —– onto its effector organ.
norepinephrine
In the PNS, a cholinergic postganglionic fiber releases acetylcholine onto its effector organ.
In the SNS, an adrenergic postganglionic fiber releases norepinephrine onto its effector organ.
What are some exceptions to this rule?
Adrenal medulla, sweat glands,
piloerector muscles, and some blood vessels
The Effector Organ elicits a —– change to restore homeostasis
physiologic change
Preganglionic nerve fibers in the sympathetic nervous system are:
Correct Answer:
Myelinated B-fibers
The efferent limb of the ANS reflex arc consists of 2 nerve fibers. The preganglionic fiber is a —– fiber
myelinated B- fiber
The efferent limb of the ANS reflex arc consists of 2 nerve fibers. The postganglionic fiber is a —– fiber
unmyelinated C-fiber
References**:
- Barash. Clinical Anesthesia**.* 8th ed.* *201*7. *p. 333-335**.
- Hall.* Guyton and Hall Textbook of Medical Physiology 12th ed. 2013. p. 560 & 729- 7**31.
