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ANS
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- 1What is ANS?System of motor nerves (efferents) that function to regulate activity of SM, CM, glands & neurons in GI tract (ENS)
Critical 4 homoeostasis (regulates GI motility, BP, body T...). Self-governing - 2What r 3 subdivisions of ANS?SY, PASY, ENS
- 3What's the function of the ENS? What does it consist of? How is related 2 rest of ANS?Works autonomously 2 control activity GIT
Mainly myenteric plexus (between circular & longitudinal SM in ME)but also SM plexus
Receives autonomic innervation from PASY & SY divisions - 4What is function of SYNS?SY: fight or flight=>increased delivery O2+ glucose 2 muscles (increased HR & SV=>increased CO, vasodilation at muscles, vasoconstriction at viscera, glucose release into blood, increased light entering eyes - better visual accuity)
- 5What is function of PASYNS?PASY: rest & digest=>conserve body resources (decrease HR 2 lower BP, increase secretion enzymes, increase digestion & GI motility, promote removal waste products)
- 6What is basic organisation of ANS?Preganglionic neuron (CNS)=PNS=> Autonomic ganglion=>Postganglionic neuron=>target
- 7What is basic anatomy of PASYNS (origin, innervation, effects of stimulation)?Originates brainstem & sacral SC, sacral preganglionic neurons don't join spinal nerve (own nerves: pelvic splanchnic nerves=>contracts bladder), cranial preganglionic neurons travel w/axon in cranial nerves: vagus/X (lungs=> constricts bronchi, heart=>slows heartbeat, stomach+small intestine=> peristalsis & secretion, liver=>bile release), occulomotor/III (pupil size=> constricts pupils, lens strength), facial/VII (salivary glands=>stimulates flow saliva), glossopharyngeal/IX (SM & glands of throat, viscera of thorax & abdomen)
- 8What r characteristics features of PASY NS wiring? What r NT & R used in PASY NS?Preganglionic fibres long & branched, innervate ganglia located on/close 2 target organ, postganglionic neurons short projections 2 innervate target organ
Preganglionic neuron=>ACh=>nAChR=> postganglionic neuron=>ACh=>mAChR=> effector organ - 9What is basic anatomy of SYNS (origin, wiring features, stimulation effects)?Originates thoracic & upper lumbar SC, short unbranching preganglionic neurons, innervates ganglia close vertebral column, postganglionic neurons long branching projections innervate target organs (dilates pupils, inhibits salivation, relaxes bronchi, accelerates heartbeat, inhibits peristalsis & secretion, conversion glycogen 2 glucose & release in liver, secretion A & NA, inhibits bladder contraction, orgasm) SY preganglionic neurons arise LH spinal GM, axons leave SC ventral root, travel white rami enter SY chain, then can 1) synapse w/postganglionic neurons in SY chain, 2) travel along SY chain b4 leaving along nerve 2 innervate outlying ganglion or adrenal gland, 3) leave SY chain to innervate collateral ganglion
- 10What r 3 SYNS pathways from CNS 2 effector organs (w/ adrenergic R)?1. PreGN=>ACh=>nAChR=>PostGN (SY chain)=>NA=>AR=>effector organ
2. PreGN=>ACh=>nAChR=>PostGN (collateral ganglion)=>NA=>AR=>organ
3. PreGN=>ACh=>nAChR=>chromaffin cell (adrenal medulla)=>A=>AR=>effector organ - 11Where does neurotransmission happens between ANS & SM?Varicosities
- 12Do autonomic neurons only release NA (SY) or ACh (PASY+SY)?No, other transmitters often co-released like NPP (VIP, NPY, substance P) or small molecules like 5-HT, ATP, NO
- 13What r main features of nAChR?LGIC, activated by nicotine (& ACh), non-selective cation channel (main response influx Na+ but also permeable K+)
- 14What r main features of mAChR (PASY)?5 types encoded by 5 genes: M1-M5
Grouped into 3 classes: M1R (excitatory e.g. stimulation vagus=>secretion gastric acid), M2R (inhibitory in heart & nerve terminals CNS & PNS e.g. slowing heart via vagus), M3R (excitatory in secretory glands & SM e.g. contraction visceral SM) - 15How does α1-AR work?A/NA=>α1-AR (Gq)=>PLC=>PIP2=>IP3+DAG =>Ca2+(ER)+PKC=>phosphorylate+respons
- 16How do α2-AR & β-AR work?A/NA=>α2-AR (Gi)=|AC=|cAMP=|PKA=| phosphorylation=|response
A/NA=>β-AR (Gs)=>AC=>cAMP=>PKA=> phosphorylation=>response - 17What r main features of AR?2 major classes:
α (1, 2)=excitatory
β=excitatory (1, 3) or inhibitory (2)
β1=>stimulates CM, β blockers treat hyperT
β2=>relaxes bronchial SM, A treat asthma
β3=>excitatory effect on adipose tissue - 18PostGN of SYNS are only adrenergic (T/F)F: very few are cholinergic=>secrete ACh to activate mAChR e.g. sweat glands, piloerector muscles
- 19What is the effect of a) SY & b) PASY on: 1. eye 2. lacrimal gland 3. salivary gland 4. heart 5. blood vessels 6. lungs 7. liver 8. adrenal gland 9. GIT 10. Kidneys 11. Genitalia 12. Sweat glands 13. Hair follicles 14. Urinary bladder 15. Metabolism1. a) pupil dilation b) pupil constriction
2. a) no effect b) secretion of tears
3. a) vasoconstriction, secretion viscous fluid b) vasodilation, copious secretion saliva
4. a) +ve chronotropy, +ve inotropy
b) -ve chronotropy
5. a) mainly vasoconstriction, vaso-dilation in muscle b) no effect
6. a) bronchodilation b) broncho-constriction, mucous secretion
7. a) glycogenolysis, gluconeogenesis, release glucose b) bile secretion gall bladder
8. a) secretion A+NA b) no innervation
9. a) decreased motility & secretion b) increased motility & secretion
10. a) vasoconstriction & decreased urine output b) no effect
11. a) ejaculation b) erection
12. a) secretion sweat b) no innervation
13. a) piloerection b) no innervation
14. a) inhibits micturition b) initiates it
15. a) increase b) no effect - 20Describe autonomic control of heartSAN: β-AR increase HR, M2 decrease HR
AVN: β-AR increase conduction, M2 decrease conduction
Ventricle: β-AR increase contraction - 21Which common therapeutics rely on ANS?I-V A: wide SY effect (anaphylactic shock);
α1-A A: nasal decongestants, benign prostatic hyperplasia; β1 B: decrease BP;
β1 & β2 B (β blockers): vasodilation & decreased HR & contractility;
β2 A: stimulate bronchodilation via relaxation of airways (asthma) - 22Describe the baroreflexIncrease BP=>baroR carotid sinus & aortic arch=>SY inhibition+PASY activation=> bradycardia+vasodilation=>decrease BP
- 23Where are baroR located? How are baroR innervated?Carotid sinus R: carotid sinus nerve=>nerve IX (glossopharyngeal)
Aortic arch R: vagus nerve X - 24What happens when you move from a supine to upright position in terms of BP?Move supine 2 upright=>↓venous return=> ↓SV=>↓CO=>↓BP=>↓baroR activity=>↑SY activity heart & blood vessels+↓PASY activity heart=>↑TPR+(venoconstriction=> ↑venous return=>)↑CO=>↑BP
- 25Which higher centres involved autonomic control (apart from SC & brainstem)?Hypothalamus, forebrain, amygdala, hyppocampus, many others
- 26How are higher centres involved in fight or flight response?Potential danger needs be recognised (forebrain), hypothalamus initiates & maintains response (activates SY, inhibits PASY, alters sensitivity baroreflex, promotes cortisol secretion)
- 27Where do PASY & SY originate?PASY: CN III, VII, IX, X; S 2-4
SY: T1-L3 - 28What is special about neurotransmission in ANS (e.g. as opposed 2 that in somatic NS)?Target cells ANS no specialised R sites - synaptic transmission multiple sites along highly branched axon (varicosities)
NT diffuse some distance b4 R (+diffuse control than somatic NS - V transmission) - 29What r 2 major classes of AChR? What r respective A, B & effects (EPSP/IPSP)?nAChR: A=nicotine, B=curare/ hexamethonium, effect=excitatory
mAChR: A=muscarine, B=atropine, effects=excitatory/inhibitory - 30Describe main features of each of ARα1: vascular SM, pupil; NA>A; IP3; EPSP
α2: CNS, platelets, A/NA terminals (autoR), adipose tissue; NA>A; inhibits cAMP; EPSP
β1: CNS, CM, kidney; NA=A; +cAMP; EPSP
β2: blood vessels, respiratory tract, uterus; A>>NA; +cAMP; IPSP
β3: adipose tissue; NA=A; +cAMP; EPSP - 31How does ANS regulates pupil diameter?PASY: stimulate circular muscle(constriction
SY: stimulates radial muscle (dilation) - 32Is fight or flight response only regulated by ANS?No, integrated activity of ANS and somatosensory NS: cortex (PFC+insula)> amygdala (subcortical, limbic system)> somatic motor nuclei (brain+SC) // hypothalamus (diencephalon)> PASY nuclei (brainstem)+SY neurons (SC)
- 33Why is hypothalamic pituitary axis important?Controls secretion many hormones
Regulates e.g. body T, BP, hunger/satiety... - 34Contrast anterior and posterior lobes of pituitary glandAnterior (adenohypophysis): parvo-cellular neurosecretory cells=hormone transport axons=>hypophysiotropic hormones released=portal system=> stimulation/inhibition anterior pituitary hormone release=blood=>organs
Posterior (neurohypophysis): magno-cellular neurosecretory cells produce neurohormones in soma=transport in vesicles down axon: neurosecretory tract =>release blood (posterior lobe)=>organs - 35What are tropic hormones?Cause the release of other hormones
- 36What are 3 wiring pathways of SYNS?PreG soma in SC (T1-L3), fibres via white rami 2 SY chain (paravertebral) ganglia each side SC, axons preGN may: 1) synapse postGN in 1/+ paravertebral ganglia; 2) synapse peripheral ganglia (prevertebral/collateral: e.g., coeliac, mesenteric); 3) synapse adrenaline producing cells (adrenal medulla). Axons postGN w/soma SY chain either: 1) pass back in2 spinal nerves (via grey rami) 2 innervate vascular SM (blood vessels of skin & SKM), sweat glands or piloerector muscles; 2) pass in2 visceral nerves (e.g., cardiac, splanchnic, renal SY nerves)
- 37What is divergence & convergence in pre to postganglionic synaptic transmission?Divergence: w/in ganglia axons preGN branche 2 innervate a nº of postGN
Convergence: each postGN innervated by >1 preGN - 38What r main actions SYNS?1. ↑HR+F CM contraction=>↑CO
2. relaxes SM airways (via A)=>↓airway R
3. pupil dilation
4.↑blood glucose (A from adrenal medulla)
5. piloerection
6. ↓activity GI tract - 39What r main actions PASYNS?1. ↓HR (=>↓CO)
2. constricts SM airways (↑ airway R)
3. pupil constriction
4. ↑activity GI tract
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- Physiology Karteikarten am ANS, erstellt von Francisco Sacadura am 01/04/2017.
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- Francisco Sacadura
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