autonomic nervous system Flashcards
ANS is the – branch of – division of the PNS and it controls the body’s — environment aka – activities in a coordinated manner as:
- internal organs/ visera controlled by ans are:
- involuntary
- efferent
- internal
- visceral
- hear rate and circulation, digestion , and respiration
- heart lungs stomach git spleen pancreas bladder and rectum kidney and liver and eye ( pupil )
-A muscle or gland innervated by autonomic fibers is called an —
-If the autonomic nerve fibers to an effector organ are cut, the organ may continue to —-, but will lack the capability of —-to changing conditions.
- effector organ
- function
- adjusting
- CNS has a —
- the regions regulating ANS are:
1- — and — in — which control the:
2- — which has a major role
3- —– for:
- central control
- medulla and pons in brain stem for controlling cvs respiratory and digestive fats
- hypothalamus (-> HPA, Hypothalamus-Pituitary-Adrenal Axis) for heart rate bp , respiration( via medulla)
- spinal cord for:
Integrates autonomic reflexes not subject to higher control e.g. urination, defecation
the 2 divisons of ANS are: and these are — activated under most circumstances aka – activity
- symothatic and para
- partial
- tonic activity
( Technically, the enteric nervous system is a 3rd division: vast network of nerve fibers that innervate the digestive tract
—– is for restoring and maintaining - rest and digest and is not rewired for emergencies which allows us to conserve and unwind energy
—– is activated in emergency situation in fight or flight and involves stress
- advantages of dual system includes :
- para
- sympthayic
- Advantage of „dual system“”
-Rapid and precise control over organ/tissue‘s activity
-Like having an accelerator and a brake on a car
e.g. like letting up on accelerator vs applying brake
-Very rapid transitions from rest state to fight or flight
—- promotes normal maintences and secretion ad mobility of different parts of digestive tract and at involves urination and defecation
para
—- emergency situations, body needs sudden burst of energy
1- it increases —- and pulmonary —
2- routes — to —
3- raises — and — digestion
4- kidney —- and other fucntions not needed in emergencies
- the whole —-system tends to go off together but — doesnt
- sympthatic
- caridac output
- pulmonary ventilation
- blood to muscle
- raise blood glucose
- slows down digestion
- filtration
- sympthatic
- para
-Each ANS pathway from CNS to organ/effector is —-
from CNS —> —- > —-> —>
- two-neutron chain
- pre ganglion —> ganglion — > postganglion — > organ
( check slide 15 pls)
origins of symothatic and para are from different parts of cns
1- para:
1- pregnaglionic : —– and —- , the preganglionic nerves are — and —-
2- postganglionic nevose are — and —
- cranial ( x-vagus nerve ) and sacral ( lower spinal cord )
-long and myleinated - short and unmylinated
( check slide 18 pls)
origins of sympthetic:
- pregangloinc from : —- and — of the spinal cord
- these are — and —
- symothatic postganglioni are — and —-
- sympthatic ganglia lie in — either side of spinal cord and have sympathetic trunk
- thoracic and lumbar ( T1-L3)
- short and myelinated
- long and unmylinated
- chain
( check slide 20 )
ANS uses 2 main neurotransmitters which are: — and —-
- all preganglionc ANS release —
- achetcholine ( ACh )
- noradrenaline ( NA)
-ACh ( so both pre and postganglionic release ach)
check slide 22 plsss
1-Each autonomic NT can stimulate activity in some tissues but have lower activity in others
- na — heart rate and — contraction of digestive tract
- repose is property of — not —
- tissue/organ targets possess — receptor by binding of nt induce —
- increases
- decreases
- tissue
- not nt
- one or more
- tissue-specific réponse
check slide 24 soo important
1- in para:
- all are receptors for:
- but ACh receptor is different at — and —
2- in sympathetic:
- AChR at — and NA-R at —
- ACh
- ganglion and target tissue
- ganglion
- target tissue
cholinergic receptor- 2 types that bind to acetylcholine:
1- nicotine:
- found in all —–
- r activated by ach released from —-
- r also activated by — derivative nicotine
- its —- hence 000 responses
2- muscarninc:
- binds ACh released from —-
- found on —-
- r also activated by —
- – types of muscarine ACh receptor
- all G protein-coupled —– receptors
- === acting effect
- post ans cell bodies
- pre either para or symp
- tobacco
- inotropic
- fast
( *NN or N2 – the NM or N1 is at the skeletal neuromuscular junction) - post of para nerves
- effector cell menrvabes as smooth muscle glands or cardiac muscle
- mushroom poison muscarine
- 5
- metabolic
- slow
muscarinic receptors:
1- M2: has —- response
- located on —
- receptor couples to increase —- and inhibits —
- eg:
2- m3 has — response
- located in —
- G proteins couples to —
- example :
- inhibitory
- cardiac tissue
- k+ conductance
- calcium channels
- decrease heart contraction
- excitatory
- digestive ssutyem
- ca+2 second messenger system
- increase granular secretion and increase GIT motility
( check slide 35 , 37)
adrenergic receptors are found only at — in —-
- 2 major classes that binds to :
- alpha and beta all couple to — but —- differs
-effecor organ in post and after postganglionic sympthatic nerves
- NA and AD
- G proteins
- intracellular coupling ( check slide 41)
1- alpha1:
- has – repose
- located on most —-
- G proteins couples to —
- examples:
2- alpha 2:
- has — response
- located on —
- g rrptein couples to inhibits —
- example:
- b1:
- has — response
- located in –
- couples —
- example:
- b2:
- has — repose
- located in —-
- couples via —
- exmaple :
- excretory
- most sympthatic cells
- ca+2 second messenger system
- increase contraction arterioles –> raised blood pressure
- inhibitory
- digestive sytem
- CAMP system
- decrease smooth muscle contraction – > reduced GIT motility
- extirtoy
- heart
- couples via G protein to cyclic AMP/PKA
- contraction of cardiac muscle –> increase rate n force
- inhibitory
- Skeletal muscle, smooth muscle of some vessels & organs
-Couples via G protein to cyclic AMP/PKA
-e.g. relaxation of smooth muscle → bronchiolar dilation
t or f:
Effector organs/tissues express receptors for the NT of both types of postganglionic fibres:
as in post para and post sym
true
termination of NT effect:
1- acetylcholine is destroyed by —- at —
2- noradrenaline reuptake by — then —
- acetylcholinesterase at synpases
- Re-uptake by pre- and post-synaptic cell then metabolized/re-cycled
adrenal medulla :
1- extension of —
2- 2 adrenal glands next to —
3- has —-
4- medulla modified sympthatic ganglion without —-
5- preganglionic fiber directly stimulates hormone release from —
- sympthatic nervous system
- adrenal next to kidney
- outer portion , adrenal cortex , inner adrenal medulla
-postganglinic fiber - chromffin cells
( 20% nor and 80% adrenaline )
-Salivary gland secretion increased via —–
- sweat gland mainly — and –
- via both sympathetic and parasympathetic input
((Parasympathetic innervation controls most of the flow of saliva, while
sympathetic innervation modulates the composition of the saliva) - Sweat glands
Mainly sympathetic innervation and terminal fibre release ACh(!) not NA(!)
steps of neurochemical transmission for potential targets of pahrmacolgocial intervention
1- nerve terminal for —
2- post synaptic membrane for —
3- neurotransmitter effect termination for —
- neruotrasmitter release
- nerotransmiter-receptor reaction
- neurotransmitter degradation
drugs:
Drugs can selectively mimic (agonists) or inhibit (antagonists) ANS responses at receptors
Some are therapeutically useful
Muscarinic antagonist (all mAChR): Atropine
Blocks muscarinic R
Blocks parasympathetic actions at effector tissues
Reduces salivary and bronchial secretion (e.g. during surgery
1-salbutamol :
- a adreneginc —
- activated inhibitory —
- used for:
- lack of effect at — so no effect in —
2- atenolol :
- is adrenegnic —
- blocks excitory —-
- cvs:
- agonist
- b2 adrenergic receptor
- dilated bronchioles for treatment of asthma/COPD
- b1 so no effect on heart
- antagonist
- blocks excitatory b1 adrenergic receptors
- Lowers blood pressure - treatment of hypertension
— is an autonomic dysfunction
- dysautonomia
Many forms: Orthostatic hypertension, neurocardiogenic syncope, chronic stress disorders (chronic activation of HPA (hypothalamic-pituitary-adrenal) axis)
Trauma, Inflammation, Drugs, Neurodegenerative disease
E.g. deficiency of sympathetic activity to lesion /compression (trauma, tumor) in Horner’s syndrome: drooping eyelid (ptosis) + constriction of pupil (miosis) together with anhydrosis (decreased sweating)
