module 6 Flashcards
(48 cards)
what does the sympathetic nervous system do
Prepares the body for heightened activity.
Involved in flight or flight
increases cardiovascular and respiratory activity:
Shuts blood to skeletal muscle and heart
Reduces blood flow to nonessential organs
Dilates bronchioles
causes liver to release glucose
Increases sweat gland activity
Dilates pupil (to allow distance vision)
Decreases digestive functions and urination
what does the parasympathetic nervous system do
stimulates abdominal visceral activity, conserves energy=rest and digest
Directs digestions, diuresis/micturition, defecation
Decreases cardiovascular and respiratory activity
Constricts pupils (to allow near vision)
Eg, relaxing and reading after a meal
in what ways are the somatic and autonomic nervous system different
Neural (efferent) pathways
Effectors
Organ response
Neurotransmitters
whats the somatic nervous system do
Conducts motor impulses from primary motor cortex to skeletal muscles
what motor pathways does the somatic nervous system involve
upper motor neurons
Lower motor neurone
whats somatic output control
voluntary movement Somatic reflexes (involuntary movement)
whats the automomic nervous system do
- Conducts motor impulses from hypothalamus to cardiac and smooth muscle and glands.
- May involves brain steam nuclei (medulla oblongata)
- Influences by cerebral cortex and limbic system.
what motor pathways does the autonomic nervous system include
CNS interneuron
Pre ganglionic neuron
Post ganglionic neuron
what autonomic output controls
involuntary activities
visceral organ function
Glandular activity
Visceral reflexes.
whats the somatic motor pathway
Efforts (skeletal muscle) innervated by a LMN that exits the CNS via a:
Spinal nerve: LMN cell body located in a motor nucleus of anterior grey horn, Axon exits the spinal cord via a ventral root of a spinal nerve
Cranial nerves: LMN cell body located in a brainstem nucleus
LMN heavily myeilated
LMN releases acetylcholine (ACh) at the synapse with the effector
ACh= always excitatory, resulting in a skeletal muscle contradicti
whats the preganglionic neuron autonomic motor pathway
cell body in CNS- motor nueclei in brain stem or lateral gray matter (parasympathetic) of spinal cord, or lateral gray horn (sympathetic) of spinal cord.
Lightly myelinated axon exits CNS via a cranial or spinal nerve and synapses with postganglionic neuron in a ganglion
Releases ACh, always excitatory (always results in an action potential in postganglionic neuron)
whats the post ganglionic neuron autonomie motor pathway
cell body located in a ganglion (near CNS or near effector)
Unmyelinated axon exits the ganglion to innervate the effector
Neurtranimiters release:
Sympathetic neurons eg noradrenalin
Parasympic neurons eg achtocholine
similarities of sympathetic and parasympathetic
serve many of the same organs
Preganglionic neurons: thing, lightly myelinated, release ACh
Postganglionic neurons: unmylinated
Presence of ganglia
whats the difference between sympathetic and parasympathetic ns
both divisions do not innervate all organs
Site of exit from the CNS
Length of the axons
Location of the ganglia
whats the parasympathetic division also called
cranioscaral division
whats the parasympathetic division neurons
Preganglionic neurons arise from opposite ends of the CNS; brain and sacral region of spinal cord
Ganglia located close to or within target organ
Preganglionic axon=long
postganglionic= short
whats the parasympathetic cranial pathway
Pregangionic axons leave motor nuclei of brain stem via cranial nerves
CN III=oculmotor nerve, controls diameter of pupil
CN VII= facial verve, salivary, nasal and lacrimal glands, tears
**CN X= viragos nerve, neck, thoracic and abdominal visceral organs. ONLY one that extends from the neck region.
whats the parasympathetic scram pathway
Preganglionic neuons:
cell body in motor nuclei of lateral gray matter(not horns)
Axon exists via ventral root of the spinal nerves associated with the sacral spinal cord.
Postganglionic neurons innervate:
pelvic organs (balddre, reproductive organs)
Distal portion of large intestine
whats the sympathetic division also called
thoracolumbar division
whats the neurons in the sympathetic division
All preganglionic fibres arise within spinal cord segments T1 to L2. Exist spinal cord via spinal nerves Ganglia located close to spinal cord Preganglionic axon= short Postganglionic axon= long
whats the sympathetic trunk
chain of 23 ganglia connected by fibres to form sympathetic trunk, flanks both sides of the vertebral column, extends from neck to pelvis
wheres the adrenal medulla located
inner region of the adrenal gland
whats the adrenal medulla part in the sympathetic response
Sympathetic preganglionic fibres:
Synapse with endocrine cells within the adrenal medulla
Release ACh which stimulate these endocrine cells to secrete adrenaline (A) and noradrenaline (NA) to interstitial fluid to the blood. **ONCE IN BLOODSTREAM the neurotransmitters are known as hormones
A and NA move through vassal system —-> effect any cell bearing receipts for these hormones
** therefore enhances and prolongs the sympathetic response
whats the visceral reflexes
automatic motor response to a stimulus to act to preserve homeostasis
Reflex may be facilitated or inhibited by higher centres (eg hypothalamus)
EXAMPLES:
Baroreceptor reflex, controls blood pressure
Pupillary (consensual light) reflex
