Chapter 15 PowerPoint Flashcards
The autonomic nervous system is often associated with the ____ ____ ____ response
Fight or flight
What 7 things occur when the flight or flight response is activated?
Adrenaline is secreted into the circulatory system
Heart rate increases
Bronchi of lungs dilate
Pupils also dilate
Blood vessels dilate
Blood pressure increases
Sweat glands are activated
What are two divisions of the nervous system?
Somatic nervous system
Autonomic nervous system
What does the somatic nervous system control?
Skeletal muscle contraction
What 3 things does the autonomic nervous system control?
Controls cardiac muscle, smooth muscle, and glandular secretions
Which division of the nervous system is voluntary?
Somatic nervous system
Which division of the nervous system is involuntary?
The autonomic nervous system
What are the two division of the autonomic nervous system?
Sympathetic division and parasympathetic division
What response is associated with the sympathetic division?
Fight or flight response
What response is associated with the parasympathetic division?
Rest and digest response
What is another name for the sympathetic division?
Thoracolumbar division
What is another name for the parasympathetic division?
Craniosacral division
____ is a balance between the two divisions of the autonomic nervous system?
Homeostasis
What is an example of homeostasis in the autonomic nervous system? (circulatory system)
For eg., the heart is innervated by nerves from both systems to either speed up the heart (sympathetic) or slow it down (parasympathetic)
What occurs during activation of the sympathetic division of the ANS?
-What systems are activated?
-What prevents overheating?
-What system is deactivated?
Respiratory, cardiovascular and musculoskeletal systems are all activated to facilitate delivery of O2 and other nutrients to skeletal muscles
Sweating keeps the body from overheating during increased skeletal muscle usage
Blood flow to the digestive system is shunted since there are higher priorities at this moment
The sympathetic division is also known as the ____ ____ to reflect the origins of the spinal nerves?
Thoracolumbar system
The majority of ganglia of the sympathetic division belong to the ____ ____ ____ that run alongside the vertebral column?
Sympathetic chain ganglia
Thoracolumbar system?
Alternate name for the sympathetic division of the autonomic nervous system that is based on
the anatomical location of central neurons in the lateral horn of the thoracic and upper lumbar spinal cord
Sympathetic chain ganglia?
Series of ganglia adjacent to the vertebral column that receive input from central
sympathetic neurons
Ganglia vs nucleus/nuclei?
Bundle of neuron cell bodies found in the PNS vs bundle of cell bodies found in the CNS/brain
What are paravertebral ganglia?
Autonomic ganglia superior to the sympathetic chain ganglia
How many ganglia are on each side of the spinal cord per area/segment?
3 cervical
12 thoracic
4 lumbar
4 sacral
=23 total
The ____ and ____ levels of the sympathetic chain ganglia do not connect directly to the spinal cord via spinal roots?
Cervical and sacral
What is an effector?
A cell that performs a specific function in response to a stimulus
What are the three types of junctions within the sympathetic system?
a. Sympathetic nerve projects at same level as the target effector
b. If target is superior or inferior to the spinal segment
c. Associated with splanchnic nerves
White ramie communicantes?
Myelinated structures that provide a short connection
from a sympathetic chain ganglion to the spinal nerve that contains the preganglionic sympathetic fiber
(singular = ramus communicans)
Gray rami communicantes?
Unmyelinated structures that provide a short connection
from a sympathetic chain ganglion to the spinal nerve that contains the postganglionic sympathetic fiber
(singular = ramus communicans)
Superior cervical ganglion?
One of the paravertebral ganglia of the sympathetic system that projects to the head
Another name fore paravertebral ganglia?
AKA?
Autonomic ganglia superior to the sympathetic chain ganglia
Cervical ganglia
Collateral ganglia?
What?
Which 3?
Where situated?
Ganglia outside of the sympathetic chain that are targets of sympathetic preganglionic fibers
Celiac, inferior mesenteric, and superior mesenteric ganglia
Situated anterior to the vertebral column
What three ganglia are associated with splanchnic nerves?
Celiac ganglion
Superior mesenteric ganglion
Inferior mesenteric ganglion
Spinal nerve tracks up until it reaches the ____ ____ ____?
Superior cervical ganglion
Celiac ganglion?
One of the collateral ganglia of the sympathetic system that projects to the digestive system
Superior mesenteric ganglion?
One of the collateral ganglia of the sympathetic system that projects to the digestive
system
Inferior mesenteric ganglion?
One of the collateral ganglia of the sympathetic system that projects to the digestive
system
(Gonads/external genitalia)
What are the two types of synapses and what is released in each type?
Cholinergic – acetylcholine (ACh) is released
Adrenergic – norepinephrine (NE) is released
When thinking about cholinergic and adrenergic synapse, we need to consider both the ____ and the ____?
Agonist and the receptor
Agonist vs antagonist?
Agonist-any exogenous substance that binds to a receptor and produces a similar effect to the endogenous ligand
Antagonist-any exogenous substance that binds to a receptor and produces an opposing effect to the endogenous ligand
Ligand?
An atom or small molecule binds to another molecule resulting in the formation of a complex
Types of cholinergic receptors?
What do they bind to?
What do they activate?
Nicotinic receptors: binds to AChR (Acetylcholine receptor) to activate ligand-gated ion channel
Muscarinic receptors: binds to AChR (Acetylcholine receptor) to activate G protein-coupled receptor (GPCR)
How are cholinergic receptors named?
Named based on exogenous ligands (ie., nicotine and muscarine), ligands from outside of the body
Cholinergic receptors?
A synapse at which acetylcholine is released and binds to the nicotinic or muscarinic receptor
Nicotinic receptors?
A type of acetylcholine receptor protein that is characterized by also binding to nicotine and is an
ionotropic receptor
Muscarinic receptors?
A type of acetylcholine receptor protein that is characterized by also binding to muscarine and is a
metabotropic receptor
G protein-coupled receptor?
A membrane protein complex that consists of a receptor protein that binds to a signaling
molecule—a G protein—that is activated by that binding and in turn activates an effector protein (enzyme) that
creates a second-messenger molecule in the cytoplasm of the target cell
Exogenous ligands?
Ligands made outside the body such as nicotine and muscarine
What are the two types of adrenergic receptors?
What do they bind to?
What are there classes?
Alpha (α) adrenergic receptor: GPCR that binds norepinephrine; includes α1 and α2 classes
Beta (β) adrenergic receptor: GPCR that binds norepinephrine; includes β1, β2 and β3 classes
Another name for adrenaline?
Epinephrine
Another name for norepinephrine?
Noradrenaline
Alpha adrenergic receptors?
One of the receptors to which epinephrine and norepinephrine bind, which comes in
three subtypes: α1, α2, and α3
Beta adrenergic receptors?
One of the receptors to which epinephrine and norepinephrine bind, which comes in
two subtypes: β1 and β2
Epinephrine?
Signaling molecule released from the adrenal medulla into the bloodstream as part of the sympathetic
response
Norepinephrine?
Signaling molecule released as a neurotransmitter by most postganglionic sympathetic fibers as part of
the sympathetic response, or as a hormone into the bloodstream from the adrenal medulla
What chemical signaling system is used in preganglionic fibers?
Sympathetic
Acetylcholine–>nicotinic receptor
Parasympathetic
Acetylcholine–nicotinic receptor
What chemical signaling system is used in preganglionic fibers?
Sympathetic
Norepinephrine → α- or β-adrenergic receptors
OR
Acetylcholine → muscarinic receptor (associated with sweat glands
and the blood vessels associated with skeletal muscles only)
Parasympathetic
Acetylcholine →
muscarinic receptor
What are released at synapses?
Neurotransmitters like ACh, E, and NE are released at synapses
What can be neurotransmitters and hormones?
Neurotransmitters like E and NE are released at synapses
E and NE can also be released as hormones into the bloodstream via the adrenal medulla
Neurotransmitters?
A signaling chemical released by nerve terminals that bind to and activate receptors on target cells
Hormones?
The body’s chemical messengers that send signals into the bloodstream and tissues
What is varicosity?
The structure of some autonomic connections that is not a typical synaptic end bulb, but a string of swellings
along the length of a fiber that makes a network of connections with the target effector
Synapses look different at the junction between ____ ____ and ____ ____?
Some texts call this the ____ ____; and neurotransmitters are referred to as ____?
Synapses look different at the junction between postganglionic fibers and target effectors
Some texts call this the neuroeffector junction; and neurotransmitters are referred to as neuromodulators
Reflex arc?
A circuit of a reflex that involves a sensory input and motor output, or an afferent branch and an efferent branch,
and an integrating center to connect the two branches
What is the main difference between somatic and autonomic system reflex arcs?
Main difference: types of effectors
Autonomic effectors are typically cardiac muscle, smooth muscle, & glands
Efferent branch?
Component of a reflex arc that represents the output, with the target being an effector, such as muscle or glandular tissue
The ____ ____ is one area of major difference between somatic and autonomic nervous system structure?
Efferent brach
How is the efferent branch one area of major differences between somatic and autonomic nervous system structure?
The output of a somatic reflex arc is a motor neuron that synapses directly with an effector (ie., skeletal muscle)
The output of a visceral reflex arc is a preganglionic fiber (or cranial nucleus neuron) which projects to a ganglion, followed by a postganglionic fiber
Visceral reflex?
A reflex involving an internal organ as the effector, under the control of the autonomic nervous system
Preganglionic fiber?
An axon from a central neuron in the autonomic nervous system that projects to and synapses with a
ganglionic neuron; sometimes referred to as a preganglionic neuron
Postganglionic fiber?
An axon from a ganglionic neuron in the autonomic nervous system that projects to and synapses
with the target effector; sometimes referred to as a postganglionic neuron
The ____ ____ is often the same between somatic and visceral reflexes?
Afferent branch
Afferent branch?
A component of a reflex arc that represents the input from a sensory neuron, for either a special or general sense
Sensory neurons from the ____ often project into the CNS to initiate the reflex?
Periphery
Although much of the sensory input derives from special or somatic senses, some visceral sensory input is ____ ____?
Not perceptible
What are baroreceptors?
Carotid arteries–> ____ nerve?
Aorta–> ____ nerve?
A mechanoreceptor that senses the stretch of blood vessels to indicate changes in blood pressure
A type of mechanoreceptor that detects changes in pressure in the carotid sinuses and the aorta
(Carotid arteries–>glossopharyngeal nerve
Aorta–Vvagus nerve)
Sometimes the ____ stimulation achieve conscious awareness and, if strong enough, will be perceived?
Visceral
Only a ____ ____ of the sensory homunculus is dedicated the perception of internal stimuli?
Small portion
Sensory homunculus?
A topographic representation of the sensory distribution of the body found in the cerebral cortex
When particularly strong visceral sensations rise to the level of conscious perception, sensations are often felt in unexpected places in what is called ____ ____?
Referred pain
Referred pain?
The e conscious perception of visceral sensation projected to a different region of the body, such as the left shoulder and arm pain as a sign of a heart attack
Why does referred pain project pain to different areas of the body?
Referred pain projects pain to a different area of the body due to the visceral sensory fibers entering into the same level of the spinal cord as the somatosensory fibers of the referred pain location
What are the two types of reflexes?
Long reflexes
Short reflexes
Long reflexes?
A reflex arc that includes the central nervous system
Short reflexes?
A reflex arc that does not include any components of the central nervous system
What is the chief difference between short and long reflexes?
Involvement of the CNS
Describe Kehr’s sign?
Presentation of pain in the left shoulder, chest, and neck regions following the rupture of the spleen
-The sympathetic and parasympathetic fibers that connect to the spleen do not overlap at the cervical region to result in shoulder pain
-Blood accumulates in the superior portion of the spleen to produce pressure on the diaphragm
-Nerves from the diaphragm take a special route
-The phrenic nerve connects at cervical levels 3-5 which is responsible for the shoulder pain
(Page 668)
Enteric Nervous system?
The peripheral structures, namely ganglia and nerves, that are incorporated into the digestive system organs
Enteric Nervous System:
In some instances, the sensory neuron may project directly to the ganglionic neuron which omits the involvement of the ____?
The myenteric plexuses of the enteric system can in some instances directly influence ____ function?
Stretch receptors being activated stimulates a ____ reflex that helps increase digestive motility?
CNS
Digestive
Short
The sympathetic and parasympathetic divisions each ____ at the target effector?
This is a ____ between chemical signals?
Compete
Competition
Postganglionic ____ fibers release ____ which binds to ____ receptors? (two answers)
Sympathetic… Norepinephrine… Adrenergic
Parasympathetic… ACh… Muscarinic
What is dual innervation?
The sympathetic and parasympathetic divisions each compete at the target effector
What are the exceptions to dual innervation?
Postganglionic sympathetic fibers that contact blood vessels within skeletal muscle; and, contact sweat glands release ACh instead of NE
There is no parasympathetic input to sweat glands that would interfere
In dual innervation the effector response is based on which ____ is released; and what ____ is present?
Neurotransmitter
Receptor
Neurotransmitter?
A signaling chemical released by nerve terminals that bind to and activate receptors on target cells
Receptor?
A protein molecule that contains a binding site for another specific molecule (called a ligand)
Dual innervation?
The pacemaker regions of the heart are contacted by postganglionic fibers of both divisions.
If NE is released onto the cardiac pacemaker cells, the cells _______________________?
If ACh is released, it binds to a muscarinic receptor that causes the cells to _________________________?
Depolarize faster and HR increases
To hyperpolarize resulting in a slowing of the heartrate
Without the parasympathetic input, resting heart rate would be ___bpm. The parasympathetic system slows it down to the resting rate of___-___bpm?
100… 60-80…
Pupillary Size:
The afferent branch responds to the light that strikes the ____ –> ____ ____ ____ –> ____ ____
–> ____
Pupillary Size:
The afferent branch responds to the light that strikes the retina –> retinal ganglion cells –> optic nerve –> diencephalon
What happens in low light conditions for pupillary size and why?
If light is low, the sympathetic system communicates via the superior cervical ganglion of the sympathetic chain
The postganglionic fiber then projects to the iris where it releases NE onto the radial fibers of the iris (sm. Muscle) causing dilation
What happens in high light conditions for pupillary size and why?
If light is high, the parasympathetic division sends a signal from the Edinger-Westphal nucleus through the oculomotor nerve
The fiber synapses with the ciliary ganglion in the posterior orbit
The postganglionic fiber then projects to the iris where it releases ACh onto the circular fibers of the iris causing constriction
What is autonomic tone?
For each organ system, either the sympathetic or parasympathetic division dominates which produces an autonomic tone
What are two examples of autonomic tone?
E.g., because the resting heartrate is directly influenced by the parasympathetic system which lowers it from 100bpm 60 – 80bpm, this system is said to be in a parasympathetic tone
E.g., blood pressure is influenced by contraction of smooth muscle in the walls of blood vessels. The smooth muscle possesses adrenergic receptors, but no significant parasympathetic connection. Therefore, the sympathetic system determines blood vessel tone
Sensory homunculus?
A topographic representation of the sensory distribution of the body found in the cerebral cortex.
The optic nerve projects directly to the ____ which in turn relays information to the ____ ____ ____?
Another projection of the optic nerve goes to the ____?
The optic nerve projects directly to the thalamus which in turn relays information to the occipital visual cortex
Another projection of the optic nerve goes to the hypothalamus
What controls the pupillary reflex?
They hypothalamus
What division of the autonomic nervous system is activated in high light? What about in low light?
In high light, the parasympathetic response is activated
In low light, the sympathetic response is activated
Output from the hypothalamus follows which two main tracts?
Along these tracts, the hypothalamus can influence the:
Edinger-Westphal nucleus of the ____ ____; or,
The ____ ____ of the thoracic spinal cord
Dorsal longitudinal fasciculus and the Medial forebrain bundle
Along these tracts, the hypothalamus can influence the:
Edinger-Westphal nucleus of the oculomotor complex; or,
The lateral horns of the thoracic spinal cord
Dorsal longitudinal fasciculus?
A major output pathway of the hypothalamus that descends through the gray matter of
the brain stem and into the spinal cord
Medial forebrain bundle?
A fiber pathway that extends anteriorly into the basal forebrain, passes through the
hypothalamus, and extends into the brain stem and spinal cord
Where is the amygdala?
The amygdala is one of the structures that projects into the hypothalamus through the forebrain bundle
Where is the amygdala?
The amygdala is a group of nuclei in the medial region of the temporal lobe that is part of the limbic lobe
What does the amygdala do?
Involved in emotional responses
When anxious or scared, the amygdala signals via the medial forebrain bundle which stimulates fight-or-flight
The preganglionic fibers that increase heart rate are called the ____ ____ ____?
Cardiac accelerator nerves
The preganglionic fibers that constrict blood vessels are called ____ ____?
Vasomotor nerves
The medulla of the brain contains nuclei called the ____ ____?
Cardiovascular center
Cardiovascular center?
The region in the medulla that controls the cardiovascular system through cardiac accelerator nerves and vasomotor nerves, which are components of the sympathetic division of the autonomic nervous system
Cardiac accelerator nerves?
The preganglionic sympathetic fibers that cause the heart rate to increase when the
cardiovascular center in the medulla initiates a signal
Vasomotor nerves?
The preganglionic sympathetic fibers that cause the constriction of blood vessels in response to signals from the cardiovascular center
Endogenous chemical?
A chemical that the body produces to interact with receptors on neurons
Exogenous chemical
A chemical introduced to the system from outside of the body (ie., a pharmaceutical or natural extract)
How does the exogenous chemical nicotine work on blood vessels?
E.g., nicotine – binds to nicotinic ACh receptors which causes depolarization of ganglionic neurons
Because nicotinic indiscriminately activates both divisions, and there is no parasympathetic input for blood vessels, blood pressure increases in response to this drug
How does nicotine affect the heart?
The heart receives both sympathetic and parasympathetic input
Nicotine would activate both pathways, causing both depolarization and hyperpolarization
Could result in an arrhythmia
Go over the chart on sympathetic and parasympathetic effects of different drug types?
Slides 50-51 of chapter fifteen or page 682
Solitary nucleus?
Receives sensory input about blood pressure and cardiac function from the glossopharyngeal and vagus nerves; activates sympathetic stimulation of heart & blood vessels
Dorsal motor nucleus of vagus nerve?
Parasympathetic functions ascribed to vagus nerve, including decreased HR, relaxing bronchioles in lungs and activating digestion
Location of parasympathetic neurons that project through the vagus nerve to
terminal ganglia in the thoracic and abdominal cavities
Nucleus ambiguous?
Contributes to parasympathetic output of the vagus nerve and targets muscles in the pharynx and larynx for swallowing and speech; contributes to parasympathetic tone of heart
