Chapter 8 Flashcards
Two categories of motor division
Somatic and autonomic
Divisions of autonomic nervous system
Parasympathetic and sympathetic
Craniosacral
Parasympathetic
Regions where nerves arise
Thoracolumbar
Sympathetic
Regions where nerves arise
Chain ganglion extend a little past these
Parasympathetic
1.Rest and digest
Responsible for constriction of eyes
Parasympathetic
Responsible for slowing heart rate
Parasympathetic
Which division constricts bronchial tubules?
Parasympathetic
Which division stimulates bile release from liver
Parasympathetic
Which division causes blood vessels to constrict
sympathetic
Which division stimulates digestive activity?
Parasympathetic
Which division causes the uterus to relax?
Parasympathetic
Which division causes the urinary system to increase urinary output?
Parasympathetic
Which division causes pupils to dilate?
Sympathetic
Which division increases heartbeat
Sympathetic
Which division dilates the bronchial tubules
Sympathetic
Which division stimulates the secretion of sweat ?
Sympathetic
Which division increases the rate of glycogen to glucose in liver?
Sympathetic
Which division decreases the activity of the digestive system?
Sympathetic
Which division stimulates the production of adrenaline and non adrenaline via the adrenal glands?
Sympathetic
Which division causes vaginal contractions?
Sympathetic
Which division relaxes the bladder?
Sympathetic
Bile
Made by liver, secreted by duodenum of small intestines.
Help emulsify fats
Gives more surface area which makes them easier to break down.
How do blood vessels constrict?
Made of smooth muscle. Causes diameter of arteries to narrow
Layers of smooth muscle in digestive system
Inner circular layer
Outer longitudinal layer helps push food
Makes up 90% of neurons in the parasympathetic nervous system
Vagus
Chain ganglion
Rows on either side of spinal cord parallel
Differences in structure parasympathetic and sympathetic
Sympathetic :Short piece of neuron goes into ganglion, attaches to chain. Longer piece of ganglion goes to target organ
In parasympathetic, longer run from spinal cord to ganglion and then shorter run to target organ.
Polysaccharide in human body that’s used to store glucose
Glycogen
Where is glycogen stored?
In liver and skeletal muscles
Why are sympathetic and parasympathetic always at tug of war?
Depends on the amount of energy needed for certain activities.
Channel energy and extra blood flow to areas where it’s needed
NT for parasympathetic division?
Acetylcholine, also signals skeletal muscle contractions
NT for sympathetic division?
Norepinephrine
Both systems innervate a lot of the same organs but they don’t get activated at the same time because
They are controlled by different neurotransmitters
Why are sympathetic and parasympathetic at tug of war
They go off at same time but are controlled by different neurotransmitters
Autonomic tone
The dominance of either the sympathetic or parasympathetic divisions of the autonomic nervous systems
Sympathetic tone
Dominance of sympathetic nervous system
Dysautonomia
Body does not send appropriate sympathetic or parasympathetic messages
Dysfunction of certain target muscles or glands
Nuclei
Pocket of cell bodies embedded in white matter
CN3
Constrict pupil
Smooth muscle iris of eye
Accomodation
Muscles of ciliary body in eye are in suspensory ligaments that change shape of lens in eye
Helps maintain clear vision far away and close up
Gets harder with age
CN5
Stimulates lacrimal gland
Mucous membrane
Sub maxillary gland
Sublingual gland
Gland that is only sympathetic
Adrenal
Ejaculation is
Sympathetic
Which cranial nerves are part of parasympathetic division?
3,7,9,10
S4
In parasympathetic nervous system
Long, pre-synaptic ganglion and short post-synaptic ganglion
Opposite of sympathetic
3 things chain ganglia can do
1.Central neuron synapses with a ganglion at the same level within the chain ganglia
- Central neuron synapses within a more superior or inferior ganglion in the chain
- Central neuron projects through the white ramus but does not synapse in a chain ganglion. Instead it continues through one of the splanchnic nerves to synapse within a pre vertebral ganglion
Ganglion
Cell bodies that are synapsing with neurons that are headed downstream target effectors
Autonomic varicosities
Knob swellings of certain autonomic axons containing mitochondria and synaptic vesicles
Exist in series in autonomic motor neuron.
Which ganglion is myelinated?
Presynaptic, post synaptic is not
How do varicosities work?
1.As AP arrives to first varicosity, its going to release NT
- NT moves across ECF to bind to ligand receptors on target effector in smooth muscle
- AP moves past the varicosity to hit next one and release more NT
Autonomic efferent motor pathway
- Autonomic presynaptic axon is myelinated .
- Central neuron synapses with the ganglionic neuron.
- Post synaptic or post ganglionic neuron has varicosities and releases neurotransmitters down the line. Bind with ligand gated channels on smooth muscle cells
Somatic efferent pathway
- Leaves ventral root through very long axon.
- Reaches skeletal muscle cell and ends in synaptic knob, which releases acetylcholine which has ligand gated sodium channels on surface of sarcolemma. Lets Na rush into muscle cell
What leaves ventral root?
Motor neuron
Shooting pain that leaves left arm and upper back?
Heart attack
Myocardial infarction
Blockage in coronary artery that feeds heart muscle leads to lack of blood flow
Ischemia
Lack of blood flow
Hypoxia
Lack of oxygen
Leads to permanent death
Why do people experience pain in their left arm when Myocardial infarction
Sensory neuron picks up trouble in heart. Autonomic sensory neurons are very close to eachother
Heart sensory fiber that is sensing damage to heart is also causing the sensory pain fiber in the skin to fire. Think about wiring where if wire isn’t insulated, electrical charge may jump
Refered pain
Feeling pain in a region besides location of affected structure
Autonomic reflexes
Long or short
Long autonomic reflex
Goes all the way through spinal cord
- Sensory receptor cell is myelinated. Travels down axon
- Signal travels through dorsal root ganglion. Synapses with unipolar neuron cell body..
- Unipolar cell body synapses with motor neuron. Motor neuron goes out to preganglionic neuron
- Goes to post-ganglionic neuron synapse
- Goes to target effector
Short reflex
Does not go back to spinal cord
1. Sensory receptor cell
2. Sensory receptor cell synapses with motor neuron in peripheral ganglion
Peripheral nervous system parts
Cranial nerves
Spinal nerves
Ganglia
Which muscles cause pupil constriction?
Circular muscles
Which muscles cause pupil dilation
Radial muscles
Mydriasis
Sympathetic system causes dilation when norepinephrine binds to an adrenergic receptor in radial muscle of iris (smooth muscle)
Phenylephrine
Dilates eyes using drops
Limbic lobe function
Memory and emotional value added to memory
Formation of long term memories
Cingulate gyrus
Applies emotional value to experiences that people have
Helps remember things under extreme stress
PTSD can’t let go of memories
Types of ganglia in Sympathetic nervous system
Sympathetic chain ganglia or
Collateral ganglia located in viscera
Types of receptors for acetylcholine
Nicotinic
Muscarinic
Sympathetic division
Myelinated preganglionic neuron releases Acetylcholine
- ACH is picked up by receptors in the post ganglionic neuron. Sends AP down
- AP goes down to different types of adrenergic receptors
Adrenergic receptors
Activated by epinephrine and norepinephrine
Adrenergic receptor types
Alpha one
Alpha two
Beta 1, 2, 3
Sympathetic exception
Sweat glands
NT before effector is ACH binding to muscarinic receptor
Parasympathetic division
Longer preganglionic neuron synapses with shorter postganglionic motor neuron.
2.Releases ACH on muscarinic receptor
Sympathetic division
Adrenal medulla
Straight neuron goes directly to adrenal medulla.
To release epinephrine and norepinephrine
Straight shot
NuLev
IBS
Reduce parasympathetic tone
Slows down stimulation of digestive system.
Causes difficulty cooling off. Can be dangerous for older people because sweat glands aren’t as active.
Why does inhibiting the parasympathetic division cause excess heat?
Blocks PNS at NT ligand gated receptor level. ACh doesn’t reach muscarinic receptors that activate swear glands
Sinoatrial node
Sympathetic and parasympathetic innervation(can make faster or slower)
Act as pacemaker
80-100 bpm
Atrioventricular node
Left vagal nerve innervates as well as sympathetic system innervation.
Passes action potentials from atria to ventricles
Beta blockers
Affect receptors in heart and blood vessels. Prevents epinephrine and norepinephrine from binding
Slow SA node down. Slows heart rate letting left ventricle fill completely. Lowers heart workload
Dilates arteries lowering BP
White Rami communicantes contain which kind of fibers
Preganglionic sympathetic fibers to sympathetic trunks
The glossopharyngeal nerves IX are responsible for activating which glands?
Parotid salivary glands
Select the effector that is innervated by the vagus nerves?
Small intestine
Liver
Gallbladder
Stomach
Pancreas
Proximal half of large intestine
Otic ganglion location
Just inferior to foramen ovale of skull
Post ganglionic neurons from the pterygopalatine ganglia innervate which target?
Lacrimal gland and nasal mucosa
Which of the splanchnic nerves terminates in the adrenal gland?
Thoracic splanchnic. Terminate in adrenal gland
Pterygopalatine ganglion can be affected by
Trauma to maxilla may affect this ganglion and alter nasal and lacrimal glands
Post ganglionic neurons from ciliary ganglia innervate which target?
Smooth muscle of eye
Post ganglionic neurons from the submandibular ganglia innervate which target?
Submandibular and sublingual salivary glands
Which part of the parasympathetic division serves the pelvic organs and the distal half of the large intestine
Sacral
Where does the sacral part of the parasympathetic division arise from ?
Neurons in lateral gray matter of spinal cord segments S2-S4
Which fibers release Norepinephrine
Sympathetic post ganglionic fibers
Which system conducts the fastest impulses?
Cell bodies in CNS connected via heavily myelinated axon to effector organs. Release ACh at effector. Which activates effector
How do the somatic and autonomic nervous systems interact closely?
Higher brain centers regulate and coordinate both somatic and autonomic motor activities. Most spinal nerves and cranial nerves contain somatic and autonomic fibers.
When skeletal muscles work hard, they need more oxygen and glucose. Autonomic control mechanisms speed up heart rate and dilate airways to meet these needs and maintain homeostasis.
Where is ACh released?
All somatic motor neurons release ACh at synapse with skeletal muscle.
All autonomic preganglionic fibers release ACh
Why is the effect of ACh in somatic system always excitatory
If stimulation reaches threshold, muscle fibers contract
Most sympathetic post ganglionic fibers release which neurotransmitter?
Norepinephrine
NT secreted by postganglionic parasympathetic fibers
ACh
Can be excitatory or inhibitory depending on location
Differences between parasympathetic and sympathetic divisions of CNS
- Originate from different locations.
Sympathetic is thoracolumbar
Parasympathetic is craniosacral
- Parasympathetic: preganglionic fibers are long. Sympathetic: preganglionic fibers are short.
- Post ganglionic fibers parasympathetic: short
Postganglionic sympathetic fibers: long
- Ganglia
Parasympathetic ganglia: within or near visceral effectors
Sympathetic ganglia: close to spinal cord
Which preganglionic neurons are lightly Myelinated?
All preganglionic neurons of ANS
Which neurons are non Myelinated?
Postganglionic neurons of ANS
Why is ans communication system slower?
2 synapses and less myelination than Somatic nervous system communication.
Explain the two neuron chain
- The cell body of the first neuron is the preganglionic neuron. The preganglionic neuron is located in the brain or spinal cord. It’s axon is the preganglionic axon and it synapses with the second motor neuron.
- The postganglionic neuron (sometimes called ganglionic neuron) is the second motor neuron. The cell body of the second motor neuron is an autonomic ganglion outside the CNS. The axon of the second motor neuron is called the post ganglionic axon and it extends to effector organ.
Cold sweaty skin is caused by
Sympathetic activation
Innervates smooth and cardiac muscle and glands
ANS
Adrenal medullary cells function
Secrete Epinephrine and NE into blood when. Sympathetic division is mobilized.
NE and epinephrine Reinforce and prolong effects of sympathetic nervous system
Similarities between sympathetic and parasympathetic nervous system
- Both part of efferent (motor) division of peripheral nervous system.
- Both target smooth muscle, cardiac muscle and glands and well as a lot of the same organs
- Both involve two motor neurons to reach their targets
How does somatic motor system work?
- Cell bodies are in CNS and their axons extend in the cranial or spinal nerves all the way to skeletal muscles. Somatic motor fibers are heavily myelinated and thick. Conduct rapidly
Reinforce and Prolong effects of sympathetic nervous system
Epinephrine and norepinephrine
The parasympathetic fibers of the facial nerves VII do what?
Stimulate large glands in head
Which glands are stimulated by parasympathetic fibers of facial nerves VII
Nasal
Lacrimal
Submandibular salivary
Sublingual salivary
Function of parasympathetic fibers of oculomotor III nerves
- Innervates smooth muscle that causes pupils to constrict and lenses to bulge.
Helps focus on close objects
Submandibular ganglion
Trauma to lower jaw may affect this ganglion found deep to mandibular angle.
Three things that can happen once a preganglionic axon of sympathetic division reaches a trunk ganglion
- Preganglionic and post ganglionic axons can synapse at higher or lower level
- Preganglionic and post ganglionic axons can synapse together at the same level
- Preganglionic and post ganglionic axons can synapse in a distant collateral ganglion
Collateral ganglia
cluster of nerve cell bodies outside of the spinal cord. Found in sympathetic chain. runs parallel to spinal cord. coordinate organs in response to stress, danger or stimuli.
4 major groups of brachial plexus
Medial to lateral:
1.ventral rami (roots)
2.roots form trunks
3. Trunks form divisions
4. Divisions form cords
Really
Tired
Drink
Coffee
Most preganglionic fibers of sacral part of parasympathetic division synapse in
Intramural ganglia in walls of distal half of large intestine,
Urinary bladder,
Ureters, & reproductive organs
White Rami carry which axons?
Preganglionic axons to sympathetic trunks
Where are white Rami found?
T1-L2
Gray Rami
Postganglionic fibers that go to periphery issue from every trunk ganglion from cervical to sacral region
Function of gray rami
Lets sympathetic output reach all parts of the body
Efferent sympathetic outflow comes from
Lateral horn of spinal cord
T1-L2
Where does preganglionic neuron of efferent sympathetic nervous system exit spinal cord?
Ventral horn
Sympathetic trunk
Chain of ganglia that goes from base of skull to coccyx
Ganglia
Collection of neuronal cell bodies outside of cns
Paravertebral ganglia
sympathetic ganglia on either side of vertebral column
Dorsal root carries
Sensory info into spinal cord
Ventral root carries
Efferent motor info out of spinal cord
Dorsal root ganglion
Contains cell bodies of sensory neurons
Dorsal ramus
Small branch that comes from spinal nerve
Ventral ramus
Large branch that comes from spinal nerve
Meningeal branch
Tiny branch from spinal nerve that innervates meninges
Rami communicantes
Have autonomic (visceral nerve fibers)
Attach to base of ventral rami of thoracic spinal nerves
Roots
Medial and make spinal nerves. Each root is sensory or motor
Rami
Distal
Lateral branches of spinal nerves
Carry both sensory and motor fibers
What kind of Rami form plexuses?
Ventral
Which ventral rami don’t branch join one another and form nerve plexuses?
T2-T12
Nerve plexus
Made from branching ventral Rami that join one another lateral to ventral column
How many pairs of spinal nerves?
31
White ramus communicans,gray ramus communicans connect to
Sympathetic ganglia
Neuron leaving the spinal cord enters the sympathetic ganglion through
White ramus
Why is white ramus White
Preganglionic fibers are Myelinated
Grey ramus
Unmyelinated
Some preganglionic fibers synapse with the post ganglionic neurons within the sympathetic ganglion and then leave through grey ramus
Neurons that synapse with spinal nerve
Synapse at same level, enter via white ramus, synapse at the sympathetic ganglion and
Post ganglionic neuron leaving by gray ramus then joins
Back to spinal nerve
Follows spinal nerve to supply target organ
Sympathetic outflow is from
T1-L2
What happens to sympathetic fibers that supply head and neck
Sent to cervical ganglia
Post ganglionic splanchnic
Autonomic fibers that have their own nerves
Don’t join the spinal nerves. Travel within their own nerves
Splanchnic nerves
Synapse in sympathetic ganglion but postganglionic neuron doesn’t leave via gray ramus and into spinal nerve, instead the post ganglionic neuron goes into its own nerve
Preganglionic splanchnic
Some preganglionic neurons do not synapse in sympathetic ganglion and instead leaves and synapses in peripheral ganglion close to target organ
The sympathetic division is more complex than the parasympathetic division because
It innervates more organs
Visceral organs in internal body cavities,
Visceral structures in superficial part of body (sweat glands, arrector pili muscles, smooth muscle in the walls of all arteries and veins
Which visceral structures are only innervated by the sympathetic nervous system?
Sweat glands
Hair-raising arrector pili muscles
Smooth muscle in the walls of all arteries and veins, both deep and superficial
The post ganglionic neurons from the otic ganglia innervate which target
Parotid salivary gland
Trauma to the ____ causes damage to ciliary ganglion
Eye
Structures innervated by Superior cervical ganglion
Salivary glands
Irises of eye
Tarsal muscles of upper eyelid
Blood vessels of head
Sympathetic trunk ganglia
Segmented and paired ganglia that lie close to the spinal cord
What innervates the nasal mucosa and lacrimal glands
Postganglionic neurons of pterygopalatine ganglia
Terminal ganglia
within wall of organ served or close to organ
Parasympathetic
Collateral ganglia
Sympathetic unpaired, anterior to spinal cord
Muscarinic receptors
ACh binding receptors of the autonomic nervous system’s target organs.
Named for the activation by the mushroom poison muscarine
Nicotinic receptors
ACh binding receptors of all AUTONOMIC POSTGANGLIONIC neurons and skeletal muscle neuromuscular junctions. Named for activation by nicotine
Cholinergic fibers
Release ACh
Adrenergic fibers
Release Norepinephrine
Where to find nicotinic receptors
- All sympathetic and parasympathetic Postganglionic neurons
2.hormone producing cells of adrenal medulla
3.sarcolemma of skeletal muscle cells at neuromuscular junctions (which are somatic targets, not autonomic)
What kind of effect is produced when ACh binds to nicotinic receptors?
Stimulatory.
Depolarizes post-synaptic cell
Where to find muscarinic receptors
All effector cells stimulated by postganglionic cholinergic fibers
All parasympathetic target organs and a few sympathetic targets like eccrine sweat glands
What happens when ACh binds to muscarinic receptors?
Effect can be inhibitory or stimulatory. Depends on type of muscarinic receptor on target organ
ACh binding to cardiac muscle receptors results in
Slowing of heart activity
ACh binding to receptors on smooth muscle of GI tract results in
Increased GI motility
Which division of the autonomic nervous system controls blood pressure through constriction of blood vessels
Sympathetic
Main integration center of autonomic nervous system
Hypothalamic controls
Which structure links emotional responses to changes in autonomic function
Hypothalamus