ANS (Autonomic Nervous System) Lecture Flashcards
(20 cards)
ANS Subdivisions
- Parasympathetic
- Sympathetic
– ANS is INVOLUNTARY
Parasympathetic (Subdivision)
- characteristic
“rest and digest system”
- involved with normal homeostasis
Sympathetic (subdivision)
- characteristic
“flight or fight”
- involved with stress either emotional or physical stress (4-5 mile run)
Dual Innervation
Heart is influenced by both parasympathetic and sympathic
Parasympathetic (Anatomical)
“craniosacral division”
- vagus nerve (cranial nerve)
– length of neurons
(long PREgang. neurons + short POSTgang.)
– location of ganglia
(terminal ganglia; right on the organ, end of synapse)
- minimal branching caused by NO mass activation
Sympathetic (Anatomical)
“thoracolumbar division”
- thoracic and lumbar area
– length of neurons
(short PREgang. neurons + long POSTgang.)
– location of ganglia
(sympathetic trunk ganglia; alongside the vertebral column)
- extensive branching or “diveregence” caused by mass activation (many organs effected)
Parasympathetic (Functions)
- Postgang. secrete Ach
Sympathetic (Functions)
- Postgang. N secrete NE (norepinephrine)
^ those secreting to the Sweat Glands secrete ACH - Postgang. N stimulate adrenal glands = secretion of adrenaline
Adrenaline is what?
A hormone that is secreted into the blood, it will then travel throughout the body. Which enhances and prolongs the sympathetic nervous effects
Constriction vs Dilation
- Constriction means decrease of material flow by closing a passageway
- Dilation means an opening/widening a passageway to increase material flow
Effects of the parasympathetic
- pupils constrict
- decreased heart rate (normal 60-80 bpm)
- no effect on adrenaline secretion
- bronchoconstriction
- little effect on blood vessels
- increases peristalsis in the GI tract
- increase glucose uptake
- NO effect on metabolic rate, blood coagulation, lipolysis
Effects of the sympathetic
- under stress = dilation of the pupil
- increased H.R (~240 bpm)
- secretion of adrenaline = prolong/enhance the effect
- bronchodilation
- constriction of B.V (abdomen and skin)
- dilate B.V to the skeletal muscles = preservation
- slow peristalsis
- increased blood glucose
- increased coagulation of blood
- increased metabolic rate
- increased lipolysis (fat breakdown)
- decreased urine output
- stimulate sweat glands
Why do we have opposing effects (dilation, inhibit)
Because of different receptor types
- Beta 1 on heart and adipose (NE + Beta 1 = stimulatory)
- Beta 2 Receptor on the Bronchiole = inhibitory of bronchiole dilation
Receptor Types
- Cholinergic: responds to ACH
- Adrenergic: respond to NE
Cholinergic Receptors
- subtype
- Nicotinic Receptor: respond to nicotine and ACH
- found on ALL postgang. N and the adrenal medulla
- effect: excitatory (ex. cigs = increased nicotine in blood which stimulates the adrenal medulla = increased epinephrine overall increases H.R [ constriction of B.V + increased B.P / Metabolism - Muscarinic Receptor: targets all parasympathetic organs, for most it causes excitation
- found in the intestines = stimulates peristalsis
- inhibits cardiac muscle (decreased H.R)
Adrenergic Receptors
- subtype
- Beta 1 Receptors: On the Heart = increases heart rate when stimulates
- tend to be excitatory - Beta 2 Receptors: Found in the Lungs, most are on sympathetic organs
- tend to be inhibitory = bronchodilation, slows peristalsis, - Alpha 1 Receptor: most sympathetic organs
- constrict B.V = increase B.P
- found in the pupil
Effects of Drugs on the ANS
- Sympathomimetics: target adrenergic receptors which increase the release of NE
- Albuterol drug to treat asthma; dilates bronchioles + targets B2
- Phenylephrine; acts as a nasal decongestant
- binds to A1 receptors which thins out the secretion - Sympatholytic; target adrenergic receptor that will block them (disabling)
- Propranolol; beta blockers causing dilation of blood vessels. To treat hypertension - Nicotinic Agents
- Nicotine; stimulates the sympathetic NS causes increase in BP
What is it that controls the ANS
- Hypothalamus: peristalsis, body temp, water balance
- Medulla Oblongata: HR, vasomotor center, resp. center
- Limbic System: emotional response
ANS Disorders
- Hypertension “high BP”: BP is 140 over 90 OR greater, result from an overactive symp. NS could be stress
- damage to the heart and vessels
- beta blockers used as a treatment - Raynauds Disease: causes excessive vasoconstriction of the fingers or toes
- due to exposure to cold temps or emotional stress - Autonomic Dysreflexia: uncontrolled activation of the ANS
- due to quadriplegia occurring within the first year of injury
- causes increased BP 300 over 220
Epi-Pen
a syringe containing epinephrine
- used for severe allergies or bad asthma
- allergy has been activated they can either get bronchoconstriction (decreases O2) OR vasodilation ( decreases BP + BV)
- when injection has occurred to will cause brochodilation and vasoconstriction; reversing the above to save their life
