Nervous System 2 Flashcards
What are the divisions of the peripheral nervous system
Sensory/ afferent division
Motor/efferent division splits into Visceral Motor and Somatic Motor division.
Visceral Motor Splits into Sympathetic and parasympathetic
Also the Enteric
Define Afferent
carrying information into the central nervous system, usually considered synonymous with sensory information
Define Efferent
carrying information away from the central nervous system, usually considered synonymous with motor information
Define Somatic
relating to the body wall and limbs (muscles, skin, bones, joints).
Define Visceral
relating to the internal organs (heart, lungs, digestive system, kidneys, reproductive system, etc.).
What division of the nervous system controls the viscera?
Autonomic Nervous System
There are two divisions of the ANS that are responsible for the maintence of homeostasis. what are they?
Parasympathetic(“rest and digest”/ craniosacral)
and Sympathetic (“fight or flight”/ thoracolumbar)
Where is the parasympathetic neuron location?
parasympathetic preganglionic neurons arise from brain stem & from S2-S4 (Craniosacral).
Where is the sympathetic neuron location?
Preganglionic sympathetic neurons arise from lateral horns (grey matter) of T1-L2 (thoracolumbar spinal cord)
What controls the parasympathetic and sympathetic NS?
The hypothalamus
What does the autonomic nervous system have control over ?
Circulation of the blood
Activity of the Gastrointestinal tract
Body temperature
What organs/muscles/neurons does the ANS
Innervates smooth muscle, cardiac muscle and glands of internal organs (The viscera!).
Involuntary
Two neuron chain
preganglionic neurons – originate in the central nervous system (CNS); preganglionic efferent axons are lightly myelinated.
postganglionic neurons – originate in the ganglion located outside the CNS; postganglionic neurons are not myelinated
When is the sympathetic activated?
Names some examples of your bodies reactions?
When the body is under conditions of emergency
Dilated pupils, increased heart rates, increased blood pressure, induced sweating
What happens during exercise?
eg. sympathetic or parasympathetic
sympathetic vasoconstriction shunts blood from the skin and digestive viscera to the heart, brain & skeletal muscles
What is the role of the parasympathetic nervous system?
Conserves body energy and maintains body activities at basal levels - homeostasis
Is inhibition of the pancreatic enzymes sympathetic or parasympathetic?
sympathetic
Is dilation of the iris sympathetic or parasympathetic?
sympathetic
Compare the sympathetic and parasympathetic neurons .
Which has the longer preganglionic neuron?
Parasympathetic
Compare the sympathetic and parasympathetic neurons .
Where is the gap between pre and postganglionic neuron?
Sympathetic- close to spinal cord
Parasympathetic- close to organ it innervates
Compare the sympathetic and parasympathetic neurons .
Which receptors are used?
Sympathetic - usually Alpha and beta adrenergic but can be Muscarinic receptor
Parasympathetic- Muscarinic
Compare the features between autonomic and somatic motor systems.
How many Neurons?
Are they myelinated?
Somatic- one neuron myelinated, end is skeletal muscle
Autonomic- 2 neuron, myelinated then unmyelinated
How many pairs of nerves are in the spine.
What are they?
31 pairs 8 cervical nerves 12 thoracic nerves 5 lumbar 5 sacral 1 coccygeal
What is plexi?
The form nerves take when they innervate from limbs
How does the cauda equina form?
The bundle of posterior nerves are caused by the bone of the vertebral column elongating more than the spinal cord
Sensory or Motor?
Dorsal Root
Ventral Root
Dorsal Root- sensory
Ventral Root- motor
What is the name given to peripheral nerves in the head and neck?
Cranial nerves
emerge from the brainstem
Describe the structure of the spinal nerve
Roots that join to form mixed spinal nerves
Each segments of the cord gives rise to a pair of spinal nerves that consists of axons of
motor/sensory/sympathetic neurons
Describe the role of the Dermatomes and myotomes
Provides sensory and motor supply of an adjacent muscle mass (myotome) and the cutaneous supply of an area of skin (dermatome).
Define reflex
rapid, involuntary motor response to a stimulus.
Define reflex arc
receptor, sensory neuron, integration centre, motor neuron, and effector
Define spinal reflex
somatic spinal reflexes provides information on integrity of the reflex pathway and degree of excitability of the SC
Define motor neurone
a motor neuron and all the skeletal muscle fibres it innervates (these all contract together).
The finer the movement the _____ the muscle fibres/motor unit
The finer the movement the fewer the muscle fibres/motor unit
