Periphial Nervous System Flashcards
Know the anatomy of a transverse section of the spinal cord and the associated functions.
Gray Matter: Horns
White Matter: Roots
Spinal Nerves: 31 pairs
What is the pathway of an ascending signal? Descending signal?
Asc:
Sensory receptor, Sensory neuron, Ascending pathway
Des:
Motor cortex,
Descending pathway,
Motor neuron
decussation
crossing of nerve fibers from one side of the body to the other
hemidecussation
nerve fibers from one side of the body cross over to the opposite side
contralateral
the opposite side of the body or the opposite hemisphere of the brain
ipsilateral
the same side of the body
What is a plexi? What is its importance? Where are they found?
network of nerves that come from the branching of several individual nerves.
The importance of plexuses lies in their ability to provide more efficient and effective innervation to a specific area of the body.
Found through out body/spine
What are the four characteristic of a reflex?
Involuntary
Quick
Protective
Needs stimulus
Know the pathway of a somatic reflex.
- Sensory receptor stimulus
- Sensory neuron
- Interneuron
- Motor neuron
- Response
What is the function of the muscle spindle?
detect changes in muscle length and velocity of stretch
What is the difference between intrafusal vs extrafusal fibers?
Extra: fibers generate the force required for muscle contraction
Intra: fibers detect changes in muscle length
what is the autonomic nervous
system funtion
The PNS division that regulates the body’s involuntary functions and maintains homeostasis
What is the main effector organ for the somatic motor division?
the skeletal muscle
what Nuerotransmitters do the parasympathetic and sympathetic nervous systems use
PSNS: acetylcholine
SNS: norepinephrine and epinephrine
The dorsal horns of the spinal cord bring in ________information
Sensory
The ventral horn of the spinal cord puts out________information
motor
Where are the lateral horns located on the spinal cord? What are they associated with?
located in the thoracic and upper lumbar regions of the spinal cord
associated with the SNS
How is a nerve packaged? What is the outermost layer that covers the entire nerve? What is the layer that covers the bundle/fascicles? What is the layer that covers a nerve fiber?
Epineurium - outermost cover the entire nerve
Perineurium - covers the bundle/fascicles
Endoneurium - covers each individual nerve fiber
- Know the 5 parts of a reflex in order
receptor, sensory neuron, interneuron, motor neuron, and effector
What are the different types of Muscle spindles
Nuclear bag fibers:
Nuclear chain fibers:
- What are the 5 general characteristics of a somatic reflex?
Involuntary
Rapid
Stereotyped
Polysynaptic
Localized
- What is the thoracolumbar division? What part of the autonomic nervous system is this associated with?
associated with the SNS, which is responsible for activating the body’s response to flight or fight
- What are the three pre-synaptic pathways that leave the thoracolumbar division? What are their target organs?
paravertebral - target organs located in the head, neck, thorax, and abdomen
prevertebral - target organs in the abdominal and pelvic cavities
adrenal medulla- target organs throughout the body to promote the fight or flight response.
- Where are the adrenal glands found?
located on top of the kidneys, one on each side
- What division of the autonomic nervous system is the craniosacral region of the spinal cord associated with?
The PSNS
- What does the enteric nervous system control?
controls the function of the GI tract and regulating the secretion of digestive enzymes and hormones
- Which division of the motor nervous system has polysynaptic pathways? Monosynaptic?
Somatic
Mono- involves only one synapse between the sensory and motor neurons
poly- involves one or more interneurons in addition to the sensory and motor neurons,
- Sympathetic pre ganglionic fibers are _______and post ganglionic fibers are ________, where as parasympathetic pre ganglionic fibers are _________and post ganglionic fibers are _________. Why is this?
Short, Long
Long, Short
SNS fibers are located close to the spinal cord while PSNS fibers are located close to the target organ
- What do cholinergic fibers secrete? What do adrenergic fibers secrete?
Chol: acetylcholine (ACh)
Adren: norepinephrine (NE)
- Where are cholinergic fibers found? Where are adrenergic fibers found?
Chol: both the somatic and autonomic NS
Adren: primarily in the sympathetic nervous system
- What are the two types of cholinergic receptors? What neurotransmitter do they respond to? Where are they found? Do they excite or inhibit?
nicotinic: ACh, found in the neuromuscular junction, ecitation of the postsynaptic neuron or muscle cell.
muscarinic: ACh, found in the parasympathetic nervous system, excite or inhibit the postsynaptic neuron,
- List out all 4 types of adrenergic receptors. What neurotransmitter do they respond to? Do they excite or inhibit? List example of specific function of target tissue.
Alpha 1: constriction
Alpha 2: ease of norepinephrine and other neurotransmitters.
Beta 1:increase in heart rate
Beta 2 : relaxation of smooth muscle
- Explain dual innervation Do all organs have dual innervations?
where an organ is innervated by both the ANS and PSNS, not all orangs are dual
- What ANS system is stimulated by meth? What are 3 signs of meth mouth?
The SNS
- Bruxism
-Poor oral hygiene
-hyposalivation
- What four parts of the brain are involved in autonomic nervous system control?
Hypothalamus
Brainstem
Midbrain
Cerebral Cortex
Where do both Ascending and Descending tracts decussate?
The Medulla
What is the function of the golgi tendon
detect changes in muscle tension and force generated during muscular contractions
Which muscle fiber is most common? Intrao or extra
Extrafusal
Intrafusal is located in the ________
Muscle Spindle
Intrafusal is innervated by _____ Motor neurons, while extrafusal is innervated by _____ motor neurons.
Gamma, Alpha
What does the ANS include?
two main divisions: the sympathetic nervous system and the parasympathetic nervous system.
What do the 2 types adrenal glands secrete?
Outer cortex- cortisol, aldosterone, and androgens
Inner medulla- epinephrine and norepinephrine
antagonist and agonistic effects.
Agon: Both divisions work together
Antag: they work against each other
