Test 2 Study Guide 2 Flashcards
How many cranial nerves arise from the forebrain?
How many from the midbrain and hindbrain?
2
10
SAME DAVE:
Sensory Afferent Motor Efferent. Dorsal Afferent Motor Efferent
Mixed nerves:
Sensory nerves:
Motor nerves:
Most nerves are mixed
Olfaction, eyesight and other special senses are purely sensory.
No nerves are only motor, but some are predominately motor
There are 31 pairs of spinal nerves:
- Cervical:
- Thoracic:
- Lumber:
- Sacral:
- Coccygeal:
- Cervical: 8
- Thoracic: 12
- Lumber: 5
- Sacral: 5
- Coccygeal: 1
How many nerves are involved in a normal reflex arc?
3 (sensory, association neurons, motor)
How is the knee jerk reflex different from most nerve arcs?
Monosynaptic reflex
It only involves a sensory and motor nerve tract.
Reflexes proceed sensation by the brain
True
Visceral define:
Within the body
Where are somatic cell bodies located?
They are all in the CNS (no motor ganglia)
How many neurons are in the efferent pathway for:
- Somatic:
- Autonomic:
1
2
How does the autonomic nervous system conduct efferent firing (all of it will be efferent firing):
Preganglionic cell will activate a post ganglionic cell using nicotinic Ach receptors (always)
Postganglionic cell can use a variety of different neurotransmitters
How do autonomic reflexes work?
Same as somatic, 2 synapse reflexes
Which nerve is the ninth cranial nerve
Glossopharyngeal nerve
The glossopharyngeal and vagus nerve are both mixed nerves. What does this mean?
They also bring sensory information, for example blood pressure, plasma pH and oxygen information
Somatic vs Autonomic nerves:
- What happens to the muscle when the nerve is cut?
- Ach
Somatic go flaccid.
Autonomic still can retain tension and sometimes functionality (they also undergo denervation sensitivity)
Nicotinic, always excitatory for muscles. Muscuranic (or nicotonic), not always excitatory for autonomic
The heart can function automatically (pacemaker within it) how do autonomic nerves effect organs such as this?
They increase or decrease its pace.
Craniosacro division:
Thoracolumbar division:
Craniosacro division:
Parasympathetic
Thoracolumbar division:
Sympathetic (heart is in the thorax, thoracolumbar) (the adrenal gland is located with the thoracolumbar region, activation of the adrenal gland is tied to sympathetic)
Thoraco lumbar division:
- location of the ganglia:
- Nomenclature of ganglia:
- location of the ganglia: Sympathetic ganglia are normally located parallel to the spinal cord, on both sides of the spinal column - Nomenclature of ganglia: * Sympathetic chain of Ganglia Paravertebral Ganglia
Rami Communicantes:
- Gray:
- White:
- Gray:
Unmyleinated post-ganglionic sympathetic axons which leave the autonomic (sympathetic ganglion) from the sympathetic chain of ganglia and regions the spinal nerve - White:
Myelinated preganglionic sympathetic axons which depart the spinal nerve to enter the sympathetic ganglia. These nerves can travel up the sympathetic chain of ganglia up to synapse with their postganglionic cell.
What is a ramus or rami?
A branch or a part which splits apart
Explain how convergence and divergence relate to sympathetic ganglia?
What effect is caused by this?
Pre-ganglionic neurons synapse with multiple post-synaptic neurons (this can be both up, down, or at the same point in the sympathetic chain of ganglia.
Post-ganglionic neurons are also receiving receiving input from multiple pre-ganglionic neurons.
Mass activation
: allows integration of the system, so activation causes activation of the entire system. Which is always activated to some extent but can become more active by individual signals.
Splanchnic means:
Relating to the viscera.
How do splanchnic nerves differ from the normal behavior?
What are the three ganglion within which splanchnic nerves synapse?
Splanchnic nerves still take the white rami communicatus into the sympathetic ganglionic chain, however they keep going right through it and instead synapse within…
The celiac, superior mesentaric or inferior mesenteric ganglia.
One splanchnic nerve does not go to a ganglion. What does this splanchnic nerve go to?
This nerve goes to the adrenal medulla.
Define the Sympathoadrenal system:
Because of mass activation the sympathetic nervous system will activate their effector cells at the same time that the adrenal medulla will produce predominately epinephrine and some norepinephrine
What are the implications of parasympathetic nerves not traveling with the spinal nerves?
They do not reach cutaneous effectors (blood vessels, sweat glands, arrector pili) and blood vessels in the muscle system. (these recieve only sympathetic stimulation.
Four of the cranial nerves contain preganglionic parasympathetic fibers: they are?
- How is the tenth cranial nerve different from the other four?
III oculomotor
VII facial
IX glossopharyngeal
X vagus
Vagus does not synapse solely in the head but goes to widespread regions in the body.
Describe how the use of parasympathetic axons in the oculomotor nerve work.
Oculomotor nerve is the 3rd cranial nerve.
Preganglionic fibers synapse with postganglionic within the ciliary ganglion. The post ganglionic nerve stimulates the constrictor muscle of the iris, and causes a contraction of the eye.
How do you remember that parasympathetic constricts the eye?
Constriction of the eye reduces light, and you need less light in relaxed state. During an alert state you will need a lot of light.
Where is the cell body of the paired vagus nerves?
The medulla.
Do parasympathetic or sympathetic nerves have longer preganglionic axons?
Parasympathetic, as the nerves from the craniosacral division must reach the terminal ganglia located next to the effector organs.
Effector cells of both the parasympathetic and sympathetic nervous system are always governed by postganglionic axons with what exception?
Pregonglionic innervation of the adrenal medulla
What neurotransmitter is released by the sympathetic postsynaptic ganglia?
What neurotransmitter is released by the parasympathetic postsynaptic ganglia?
Sympathetic:
Norepinphrine (adronergic)
Parasympathetic:
Acetylcholine, muscurinic receptors (cholinergic)
Varicosity:
A swelling in the axon of a post-ganglionic neuron. These varicosities for synapses in passing (synapses en passant).
Synapses in passant:
- Define:
- explain how it works in tissue:
- Define:
Synapsis in passing (refers to varicosities) - explain how it works in tissue:
Sympathetic and parasympathetic synapsis in passing occurs often on the same cells. These neurons will often have antagonistic effects.
What are the types of adronergic receptors:
Define adronergic receptors:
Alpha1: Alpha2: Beta1: Beta2: Adronergic receptors bind norepinephrine or epinephrine, both produces by the adrenal gland (thus adronergic)
What type of receptors are adrenergic receptors?
Are adrenergic receptors specific to norepinephrine or epinephrine?
G protein-coupled receptors
It appears they can bind both.
Alpha 2 receptors:
- Locale and general functionality:
Different subtypes exist.
One subtype is located on pre-synaptic neurons (alpha-1 is on post-synaptic neurons), release of norepinephrine activates both alpha-1 and alpha-2, but alpha-2 activation inhibits release of norepiniphrine from the presynaptic neuron acting as a negative feedback loop.
What drug acts as an adronergic alpha-2 agonist?
What is the effect of this?
Clonidine
Clonidine stimulates alpha-2 receptors in the brain, which acts to reduce release of norepiniphrine related to parasympathetic (and possibly other) responses in the brain. This lowers your blood pressure. Clonidine relaxes the entire sympathoadrenal system.
What is the second messenger used by:
beta receptors:
Alpha-1 receptors:
beta receptors:
cAMP
Alpha-1 receptors:
Ca2+
What do Alpha-1 receptors do:
Associated with constriction, usually of smooth muscle:
- Often constrict vascular/smooth muscle
- constriction of skin and visceral vessels (reduce blood flow to skin and internal organs)
- Sphincters constrict and slow the passage of food in small intestine
- Radial fibers of iris constrict, dialating the eyes.
- Helps in secretion of glucose and glycogenolysis from the liver
What do Beta-1 receptors do:
Increase heart rate and contraction strength
What do Beta-2 receptors do:
Associated with relaxation of smooth muscles
- arterioles dilate
- Bronchioles dilate do to smooth muscle relaxation
- Glycogen release
Can sympathetic nerves cause relaxation?
- Examples:
Yes
Lungs relax, some blood vessels
Can Parasympathetic nerves cause excitation?
- Examples:
Yes
Stomach contractions
Parasympathetic ganglia which are located next to, or within their effector organ.
Terminal Ganglia
