Autonomic Nervous system Flashcards
1
Q
Divisions of the Autonomic NS
A
- sympathetic and parasympethic
- Also afferent and efferent connections
- innervates involuntary musucles glandular tissue
2
Q
Function of the ANS
A
- regulates activity of internal organs and vasculature
- homeostasis: circulation, HR, BP, RR, digestion, secretions, temperature
- reproduction
3
Q
Sensory receptors of the Autonomic NS
A
- mechanoreceptors
- chemoreceptors
- nocioceptors
- thermorecepetors
4
Q
Similarities between somatic and Autonomic NS
A
- specialized afferents and efferents
- reflex connections
- ascending and descending connections to CNS
5
Q
Differences between somatic and Autonomic NS
A
somatic
- thalamus receives most ascending info
- cerebral cortex is source of descending info
- one neuron system to PNS
autonomic
- hypothalamus receieves much of the ascending infor
- hypothalamus is source of descending info
- a two neuron system to PNS (a lightly myelinated axon to autonmic ganglia and unmyelinated axon to organ)
6
Q
Afferent system
how does it enter the CNS
A
info from visceral receptors enters the CNS via two routes:
- into spinal cord via dorsal roots
- into brainstem via cranial nerves
7
Q
Regulation of Autonomic NS
A
- viseral afferent to efferents = reflex is initiated via the afferent system
- visceral info enters the brainstem via cranial nerves to converge in the solitary nucleus
- solitary nucleus controls areas in pons and medulla and modulates areas in the hypothalamus, thalamus and limbic system
8
Q
the efferent system of Autonomic NS
control of the efferent system
A
- medulla regulates the autonomic efferent system in spinal cord and vagus nerve
- hypothalamus is the master controller of homeostasis via pituitary, brainstem, and spinal cord
- visceral info from thalamus projects to limbic system (increase HR with anxiety)
- connect with somatosensory nociceptive afferents as in referred pain
- connect with somatic efferents as in muscle guarding
9
Q
How is the CNS connected to the autonomic effectors
A
- preganglionic from CNS to ganglion
- post ganglionic connects ganglion with organ
10
Q
what are the three systems within the Autonomic NS
A
- sympathetic NS
- parasympathetic NS
- enteric NS
11
Q
comparision of sympathetic and parasympathetic NS
A
- sympathetic nervous system also known as the thoracolumbar or adrenergic system and postganglionic neurotransmitter = NE
- parasympathetic NS is known is cranosacral and postganglionic NT = AcH
12
Q
function of the Sympathetic NS
A
- optimal blood supply to organs (orthostatic hypotension if this doesnt happen)
- respose to flight or fear
- maintain blood pressue with change of position
- regulation of body temperature (adrenal medulla releases epi.)
- blood flow regulation in skeletal muscules
13
Q
Fight or flight response
A
- sweating
- hair cells
- pupil dilation
- vasoconstriction in skin and gut to increase blood flow to active muscules
- blood glucose levels increase
- bronchi and coronary vessels dilate
- BP/HR increase
- sympathetic firing decreases digestive system activity
14
Q
Sympathetic NS efferent
preganglionic
A
- cell bodies of preganglionic neurons are in lateral horn of spinal cord T1-L2
- preganglionic neurons innervate adrenal medulla a specialized sympathetic ganglion
- secretes epinephrine and norepinephrine into blood stream
- preganglionic neurons to paravertebral ganglion where they synpase or go up or go down trunk to synpse in another ganglion
- ganglia are interconnected and form a trunk runnign beside vertebrae
15
Q
Sympathetic NS efferent
postganglionic
A
- cell bodies of postganglionic neurons are in paravertebral ganglion
- postganglionic axon enters a peripheral nerve via a rami communicant
- then travels in a dorsal or ventral ramus to target organ
16
Q
Sympathetic NS efferent
paravertebral ganglion
A
- cervical paravertebral ganglion that carry the preganglionic fibers from thoracolumbar area to head, face, and UE
- lower lumbar and sacral paravertebral ganglion descend from upper lumbar cord
17
Q
Sympathetic NS efferent
Preganglionic axons to abdominal and pelvic organs
A
- pass through sympathetic ganglia without synpasing
- synpases is with an organ
- signals to GI tract: stop or slow peristalsis
- reduce gland secretion
- signals to seminal vesicles elicit ejaculation
18
Q
Parasympathetic NS structure
A
- also known as cranial sacral
- arises from CNs and spinal levels S2-S4
- cholinergic system
- post ganglionic NT = acH
19
Q
function of
Parasympathetic NS
A
- releases ACh onto end organs
- involved in more sedentary functions
- decrease pupil size, increase gastic secretion and peristalsis, slowing heart rate
- energe conservation and storage
20
Q
enteric NS
A
- function is to serve the alimentary canal
- motility of the gut can function without the CNS, though if properly functioning is modulated by sympathetic and parasympathetic systems
- the enteric NS is entirely outside CNS inculding sensory nerves, interneurons and visceral motor neurons
21
Q
ANS clinical disorders
Horners syndrome
A
- lesion affects the sympathetic pathway to the head
- sympathetic activity on one side of the head is decreased
- results in ipsilateral drooping of the upper eyelid, constriction of the pupil, skin, vasodilation with absence of sweating on the ipsilateral face and neck
22
Q
ANS clinical disorders
autonomic dysfunction: spinal shock
A
- complete lesions above T6
- autonomic dysreflexia
- poor thermoregulation
- orthostatic hypotension
23
Q
ANS clinical disorders
Autonomic dysfunction: peripheral region
A
- peripheral nerve severed = interruption of sympathetic efferents
- causes loss of vascular control, temperature regulation and sweating in region supplied by the peripheral nerve
- may lead to trophic changes in the skin
- postural orthostatic tachycardia syndrome (POTS)
24
Q
ANS clinical disorders
Autonomic dysfunction: brainstem
A
- descendign control of heart rate, BP and respiration
- cranial nerve nuclei = interference of pupil constriction, tear/saliva production, regulation of thoracic/abdominal viscera
25
Q
ANS clinical disorders
Autonomic dysfunction: cerebral region
A
hypothalamus damage disrupts homeostasis
26
Q
Syncope
A
- brief loss of consciousness due to inadequate blood flow to the brain
- high emotion
- vasovagal attack
27
Q
types of
syncope
A
- neural reflexive
- orthostatic hypotension
- cardiac arrhythmias
28
Q
Syncope
neural reflexive
A
- neurocardiogenic/vasovagal-emotional distress
- situational-cough, sneeze, defecation, urination
- carotid sinus hypersensitivity
29
Q
Syncope
orthostatic hypotension
A
- decrease of at least 20mmHg systolic BP or 10 mmHg during the first 3 minutes of standing
- gravity induced pooling of blood in the lower limbs, compromising venous return and cardiac output = decrease in arterial pressure
- spinal cord disorders, PD, peripheral neuropathy
30
Q
tests of
autonomic function
A
- BP regulation with position changes
- sweat test: amout of salt in sweat
- vasomotor test
- valsava test: blow into closed tube with small hole
