Outline  There are exceptions.

A. Autonomic nervous system

Videos from Medicosis Perfectionalis

Notes → via Transcript
Playlist → ANS Physiology

Video 1 – ANS

ϫ Introduction
– Rule → draw an imaginary line down the central
gyrus
♪ Anything in front of line → motor ♪ Mn → FM bs
† Anything behind of line→ sensory † Fm radio bull shit
♪ Also ϫ Examples in brain
† Motor → Efferent – Examples of sensory areas

† Sensory → Afferent ♪ Primary somato sensory cortex → sensory  →

 Mn → ME – SA behind the line.

 Me playing San Andreas ♪ Primary visual cortex → sensory  → behind

the line
♪ Understanding speech → speech is listened via
auditory sense → sensory  wernicke’s area
→ behind the line
– Examples of motor areas

♪ Primary motor cortex → motor  → in front of

line
♪ Moving your eyes up down left right by frontal
eye field → motor  → in front of line
♪ Talking – movement of tongue by broca’s area
→ motor  → in front of line.
♪ Same rule for spinal cord →
† Draw an imaginary line in center of spinal
cord.
† Anything in front of line → motor
† Anything behind of line → sensory
 not in the sacral area... Why not?
♪ 6. Somatic nerves have a fibers while autonomic
ones have b and c fibers... Why?
♪ 7. Somatic fibers do not relay in ganglia... Why
not?
♪ 8. Sympathetic fibers have cervical ganglia even
though they're only thoracolumbar... Why?
♪ 9. Lateral sympathetic ganglia are 12 in the
thorax, but only 3 in the cervical area... Why?
ϫ Examples of spinal cord ♪ 10. Collateral sympathetic ganglia follow blood
– Example of sensory areas vessels (fibers embedded in the wall of the
♪ Dorsal gray horn → sensory  → behind the vessel)...why?
line. ♪ 11. Parasympathetic preganglionic fibers relay
– Example of motor areas in terminal ganglia inside the wall of the target
organ... Why?
♪ Somatic nerve fiber lie in anterior horn →
motor  → front of line. ♪ 12. Sympathetic preganglionic fibers do not
relay in terminal ganglia inside the wall of the
♪ Autonomic fiber lie in lateral horn → motor in
target organ... Why not?
function  front of line.
♪ 13. Postganglionic parasympathetic fibers
† Note → autonomic nervous system is always
secrete ach, whereas those of the sympathetic
motor – never sensory
secrete nor- epinephrine. However, the
sympathetic fibers that supply the sweat glands
secrete ach why?

ϫ Classification of nervous system

Nervous system is divided into
♪ Central nervous system
† Lies in centre
† Consists
 Brain
– Questions that will be answered in
neurophysiology  Spinal cord

♪ 1. There are more somatic nerves that ♪ Peripheral nervous system

autonomic ones... Why? † Def → anything coming out of central
♪ 2. There are more sympathetic nerves than nervous system is peripheral nervous system
parasympathetic ones... Why? † Example →
♪ 3. The somatic nerves exit via the ahc whereas  Cranial nerves come out of brain
autonomic ones exit via the lhc...why?  Spinal nerves come out of spinal cord
♪ 4. Cranial autonomic nerves are
Anatomy versus physiology
parasympathetic fibers, but not sympathetic...
Why? 5. ♪ Structural unit of central nervous system →
neuron
♪ There are lhcs in the thoracolumbar area, but
♪ Functional unit of CNS → reflex arc
 † Reflex arc constitutes of → ♪ Only innervate skeletal muscles
† A stimulus felt by receptor → ♪ Is both
† An afferent sensory fiber to CNS → † Motor → locomotion
† Typically to Spinal cord (which may or may † Sensory → example golgi tendon organs
not ascend to brain) to →  In fact → Somatic sensory 2 subtypes
† An efferent motor fiber to → (Google)
† Effector organ example bicep → Effector ž detection of mechanical stimuli → light
organs causes a response. touch, vibration, pressure, and
Parts of Nervous System cutaneous tension

– CNS ž detection of painful stimuli

♪ Brain → – Autonomic →

† Cerebrum ♪ Not under conscious control

† Cerebellum † Aka automatic + involuntary

† Brain stem ♪ Always motor

♪ Spinal cord is fived into areas → ♪ Innervates

† Cervical area † Cardiac muscles

† Thoracic area † Smooth muscles

† Lumbar area † Glands.

† Sacral area ♪ Parts of autonomic nervous system →

† Coccygeal area † Sympathetic

– Peripheral nervous system † Parasympathetic

♪ Cranial nerves → † Enteric → composed of

† 12 pairs  Myenteric plexus → for motility

† Some sensory  Submucosal (Meisner’s) plexus → for

Secretions.
† Some motor
‫ ؞‬Mn → Enteric is MS.
† Some mixed
ž Even if we cut vagus + cut sympathetic
♪ Spinal nerves
chain → git will still show peristalsis.
† 31 pairs
† All are mixed
– CNS embryology crux
 Cervical → 8 pairs
♪ Central nervous system → derived from neural
ž Note → only seven vertebra but eight
tube.
cervical nerves
♪ Peripheral nervous system → derived from
 Thoracic → 12
neural crest cells.
 Lumbar → 5
 Sacral → 5
Video 2 – Embryology of ANS
 Coccygeal → 1
♪ – Skipped

Somatic vs autonomic Video 3 – Somatic Vs Autonomic

– Somatic nervous system →

♪ Under conscious control

ϫ Introduction ♪ That's why a nerve is always in peripheral
– Upper motor neuron → runs within central nervous system whether nerve is cranial or
nervous system brain to spinal cord  part of cns spinal.

♪ Lower motor neuron runs outside the cns  part

of peripheral nervous system. Brief embryology background
– Somatic vs autonomic – Trilaminar embryo →
♪ Scenario → a person running from a tiger → † Ectoderm
motor activity † Mesoderm
♪ Pathway of umn → † Endoderm
† Primary motor cortex →
† Internal capsule →
† Brain stem – cross to opposite side in
medulla →
† Spinal cord – anterior grey horn of spinal
cord
♪ Lower motor neuron → ends on a muscle
† Alpha motor fibers → myelinated 100 meters
per second
♪

Neuron

– Ectoderm give rise to →

♪ Skin
♪ Nerve impulses jump at nodes of ranvier ♪ Cns
– Nucleus → collection of cell body in cns ♪ Respiratory tract
♪ Ganglion → collection of cell bodies in pns ♪

† Examples → – Endoderm →

 Ciliary ganglion ♪ Git

 Sympathetic chain ♪

– Tract → collection of axons in cns – Mesoderm give rise to →

♪ Nerve → collection of axons in peripheral ♪ Muscles

nervous system ♪ Bones
 ♪ Connective tissue
♪ Blood
♪

– Ectoderm two subtypes →

♪ Surface ectoderm
† Give rise to epidermis of skin
♪ Neuroectoderm
† Is a/c the one which gives rise to NS.
† Give rise to →
 Neural tube
– Notochord
 Neural crest cells
♪ is part of mesoderm
♪ Neural tube give rise to →
♪ forms nucleus pulposus of intervertebral disc
† All cns cells
Intervertebral disc lies between one vertebra and
 Cns neurons next vertebra.
 Oligodendrocytes
 Glia – Myelinated vs unmyelinated
 Ependymal cells (cells which line ♪ Myelinated → include a fibers and b fibers
ventricles & make csf)
† A fibers → thick myelin sheath → 100 m/s
† Mechanism
† B fibers → thin myelin sheath → 10 m/s
 Neural tube → 2 parts
♪ Unmyelinated → include c fibers
 Cranial part → Anterior neuropore
† Speed → 1 m/s
 Caudal part → posterior neuropore
 We cannot myelinate all fibers as myelin
ž Anterior neuropore → forms brain is expensive.
ž Posterior neuropore → forms spinal  To myelinate all neurons we will eat seven
cord. or eight meals a day just to survive
† A cavity lies inside neural tube → ♪ Clinical →
 Give rise to cavity of ventricles in brain & † Multiple Sclerosis → Demyelination within
cavity of central canal in spinal cord. CNS.
♪ Neural crest give to → – Regeneration of neuron
† All pns cells ♪ Neurons cannot regenerate by mitosis but can
 Pns neurons repair damaged axons.
 Schawn cells ♪ All neurons have a neurilemmal sheath
 Glia important in regeneration.
† Adrenal medulla → † Mn → all of them have it.
 Adrenal medulla is ac a modified ganglion ♪ If an axon is severed (cut from middle) cut parts
→ males epinephrine + norepinephrine. will fuse back together, axon will heal because
of neurilemmal sheath
 ♪ Anterior is somatic motor horn
♪ Then efferent to your muscles
♪

♪ Q/a → why somatic fibers start in anterior horn

cells while autonomics start at lateral horn cells
♪ All motor fibers lies in ventral horn yeah ventral
horn has motor fibers whether they are somatic
or usually since somatic fibers have to be fastest
because you're running from a tiger let's put it as
close as possible to exit this is far away usually
♪ That's why when you were running from tiger
takes a lot of time until they leave here and they
motor fibers you needed a fibers fastest in order
go here and go here but look at somatic oh you
to survive
because you're running from a tiger it has to be
♪
fastest and that's why it's closest to exit
– Segments of spinal cord medicine may fine tuning in his feet ask a
♪ White matter pianist whether he or she would love some fine
♪ Grey matter tunings

♪ Recall rule → imaginary line ♪

† Anything in front → motor Somatic vs autonomic

† Anything behind → sensory – Rule

 Mn → fm bs ♪ For somatic → everything is 1

 Fm radio bull shit ♪ For autonomic → everything is 2
♪ Therefore → – Subtype

† Dorsal horn of spinal cord + posterior aka ♪ Somatic →

dorsal root → sensory → afferent in function † One type – no sub type.
† Anterior horn of spinal cord + anterior aka ♪ Autonomic →
ventral root → motor root → efferent in
† Two subtypes
function
 Sympathetic
 Parasympathetic
– Target organ / efferents to

♪ Somatic efferents
† Only skeletal muscles
♪ Autonomic 2 efferents
† Muscles
† Glands
♪ Muscle and glands also have subtypes
† Muscles
♪ Reflex arc
 Cardiac muscles
♪ Sensory or afferent or dorsal ramus → posterior
 Smooth muscles
horn and
† Glands
♪ Then directly to anterior horn
 Exocrine
♪ Relay in anterior horn
  Endocrine fibers.
– Function † Mn → economy flight with multiple stations
♪ Somatic only function → † Significance of ganglion in autonomic →
† Contraction of skeletal muscles. they are relay stations for regulation.

♪ Autonomic dual function →

† Increase or decrease
 ↑ or ↓ cardiac contractility
 ↑ or ↓ gastric motility
 ↑ or ↓ secretions
† Because it increase or decrease activity –
sometimes called coordinator.
– Fibers  For instance, to increase the secretion and
motility of your stomach one
♪ Somatic →
preganglionic relays into a ganglia which
† One type of fibers → a fiber or alpha fiber can decide to supply either
♪ Autonomic → ž Fundus of the stomach
† Two types of fibers ž Body of the stomach
 B fibers ž Antrum of stomach
 C fibers ž The duodenum
 One preganglionic can supply the fundus
of the stomach the body of the stomach the
antrum of the stomach and the duodenum
– Neurotransmitter

♪ Somatic →
† One neurotransmitter → acetylcholine
♪ Autonomic →
† 2 neurotransmitters
 Acetylcholine
 Epinephrine
– Ganglions † Preganglionic fibers they actually secrete
♪ Somatic → acetylcholine but posting glionic fibers it
depends if it's parasympathetic we'll secrete
† No ganglia in between – only one efferent
acetylcholine if it's sympathetic it will secrete
relay directly to skeletal muscles.
norepinephrine with the tiny exception of
† Rx → the more the synapses in an efferent sweat glands the post-ganglionic sympathetic
the slower the response fibers going to the sweat gland are going to
† Remember we are running from a tiger secrete acetylcholine
† Mn → somatic is private jet – Number
♪ Autonomic → ♪ Somatic fibers > autonomic fibers
† Have 1 ganglia and two type of efferents ♪ Rx
 1 preganglionic → type b fiber † Somatic fibers carry out fine movements in
 1 or many postganglionic fibers → type c our extremities & since somatic fibers do not
 relay large number of fibers required for
every single movement.
† Ans carry out crude functions for instance
increasing gastric acid secretion one
preganglionic can relay to multiple
postganglionic fibers.
– Control

♪ Somatic → voluntary
♪ Autonomic → involuntary
– Location

♪ Somatic →
† Faster
† Anterior horn cell closer to exit
♪ Autonomic → ♪ Autonomic ganglia → lie in the peripheral
nervous system
† Relatively slower
♪ Includes →
† Lateral horn cells farther to exit
† Sympathetic chain for sympathetic nervous
 This also answers the question →
system.
 Why somatic fibers start in anterior horn
† Terminal ganglia for parasympathetic
cells while autonomics start at lateral
nervous system
horn cells.
 One exception of peripheral nervous
system that lies in the central nervous
system
♪

Video 4 – Ganglion

♪ Most points of this video added in previous

video points.
– Ganglia is a collection of cell bodies in the
peripheral nervous system
– Examples →
Video 5 – Sympathetic NS
♪ Dorsal root ganglia → lies in peripheral nervous
– Rule → adrenal medulla secrete both epinephrine
system → sensory somatic ganglia
and norepinephrine but
♪ Sympathetic nerve endings only secrete
norepinephrine.
♪ Rx → lack enzyme pnmt – phenyl
 ethanolamine-n-methyl transferase (pnmt) only ♪ Dorsal root ganglia → sensory ganglia.
present in adrenal medulla.
♪

– Neuron is structural unit

♪ Reflex arc is functional unit

♪ Components of reflex arc → Mn – Arabic word
SRACEER (means a cockroach)
† Sensory stimulus → hot kettle
† Receptor → thermoceptors
† Afferent to CNS (in case of a painful ♪
stimulus – synapse monosynaptic directly
♪
relays to effector neuron) →
– Fibers of autonomic nervous system
† C for centre → CNS (in this case spinal cord)
♪ Preganglionic fibers →
† Efferent neuron →
† Type b fibers
† Effector organ
† Myelinated
† Response → pull away hand.
♪ Postganglionic fibers
♪
† Type c fibers
– Ganglia of autonomic nervous system
† Unmyelinated.
♪ Sympathetic ganglia → 2
♪ Myelin appears white
† Lateral (paravertebral) or
†  type b fibers or pre-ganglionic fibers also
† Collateral (pre–vertebral)
known as white ramus communicans
♪
♪ Unmyelinated appear gray
♪ Parasympathetic ganglia →
†  type c or post ganglionic fibers are also
† Are terminal ganglia
called gray ramus communicans
† Embedded within wall of target organ such as
♪ This rule is same for both sympathetic &
 Ciliary ganglia parasympathetic.
 Submandibular ♪ Note → fibers of Somatic NS →  fibers
 Sphenopalatine † Rx → fastest
 Otic ganglia – Fiber length
† Because PNS ganglia embedded / very close ♪ Preganglionic of sympathetic fibers is very
to target organ → PNS has a localized short relay in a ganglia in sympathetic chain or
response. collateral chain then post ganglionic fiber is
† In contrast SNS ganglia are far from the very long.
distance of target organ & this is why the ♪

Sympathetic response is more potent & ♪ Preganglionic of parasympathetic opposite

generalized. † Preganglionic is very long → relay in

– Ganglia of somatic nervous system terminal ganglia embedded within wall of

♪ No ganglia target organ
† Postganglionic is very short they are
♪ Relay directly to effector muscle.
– Ganglia of sensory nervous system
  Sympathetic chain extends from cervical
to sacral region.
ž Significance → we have sympathetic
ganglia in the cervical area because
some sympathetic fibers need to supply
– One preganglionic autonomic fiber synapses to → eye
† 8 to 15 postganglionic fibers ž Post ganglionic from cervical ganglia
♪ Preganglionic autonomic fibers cell bodies → will

† In lateral horn cells ‫ ؞‬Dilate pupil

† Secrete acetylcholine ‫ ؞‬Elevate upper eyelid

†  fibers called → cholinergic fibers ‫ ؞‬Exophthalmos

♪ Postganglionic autonomic fibers cell body →  Makes all ganglia of sympathetic chain
except abdomen and pelvis (made by
† Located in ganglion outside the cns
collateral ganglia)
† Neurotransmitters →
 Total 21-22 pairs of ganglia in sympathetic
 Sympathetic autonomic postganglionic
chain
fibers secrete → norepinephrine +
ž 3 in cervical region (cervical ganglia)
epinephrine
ž 11 in thoracic region
  fibers called → adrenergic fibers
ž 4 in lumbar region
 Parasympathetic autonomic postganglionic
fibers secrete → acetylcholine ž 4-5 in sacral region
† Collateral aka prevertebral
  fibers are called cholinergic fiber.
 In midline in front of spinal cord
 Not part of sympathetic chain
– Grey matter of autonomic nervous system
 Collateral ganglia includes celiac and
♪ Sympathetic nervous system cell bodies →
superior mesenteric ganglia and inferior
thoracolumbar region of spinal cord.
mesenteric ganglia.
† Entire thoracic spinal segment
 These ganglia exclusive for abdomen &
† 2 lumbar spinal segments
pelvis.
♪ Parasympathetic nervous system cell bodies →
 Only supplies gastrointestinal tract.
craniosacral
 Significance → postganglionic fibers for
† Only four cranial nerves → 3 7 9 and 10
git embedded with vessels that supply git
 Mn → 1973. in order to pierce gi tract.
† Sacral → only 1 nerve – pelvic nerve or
pelvic splanchnic nerve originates from
sacral region.
♪ Post ganglionic sympathetic fibers are present in
each 31 pairs of spinal nerves.
– Ganglia of sympathetic autonomic nervous

♪ 2 types
† Lateral aka paravertebral aka ganglia →
 2 chains parallel to spinal cord on both
sides called sympathetic chain
 energy
♪ Sources of energy →
† Glucose.
† Amino acids
† Glycerol
† Free fatty acid
♪ During sympathetic responses →
† Glycogen in liver catabolized into glucose
via glycogenolysis
† Lipid into free fatty acid via lipolysis
♪ Glucose + free fatty acid in presence of oxygen
yields energy atp.
–

– Organ response during fight or flight

♪ Who's going to supply energy to all of our cells

your heart your cardiovascular system therefore
– Sympathetic ganglia of git include →
sympathetic needs to increase heart rate increase
cardiac contractility and vasoconstrict your
♪ Coeliac ganglion.
vessels why number one to raise your blood
♪ For instance, vessel of foregut celiac trunk what pressure because you're running from a tiger
was blood vessel of midgut superior mesenteric and to reduce bleeding let's say that while
artery high in gut inferior mesenteric artery and running from a tiger you hit a branch of a tree
that's why sympathetic collateral ganglia and then you cut dorsum of your hand do you
include celiac ganglion superior mesenteric want to bleed in this moment shut up no so you
ganglion inferior mesenteric ganglion so better
sympathetic fibers let's supply stomach.
♪ Vessels
† Vasoconstriction of all vessels except
♪ Sympathetic ganglia are
 Coronary vessels
♪ Sympathetic autonomic nervous system supply
 Skeletal muscle vessels
in abdomen →
 Cerebral vessels
† Greater splanchnic sympathetic nerve.
♪ Skeletal muscles
† Relay in collateral ganglion.
† Bloof flow to skeletal muscle ↑ → blood
♪ Sympathetic autonomic nervous system supply
vessels dilate
in pelvis →
♪ Lungs
† Lesser splanchnic sympathetic nerve.
† Bronchodilation to breathe faster and deeper
† Relay in collateral ganglion.
♪ Heart →
♪ Parasympathetic autonomic nervous system
supplying pelvis → † Increase in all cardiac properties

† Pelvic nerve aka pelvic splanchnic nerve. † ↑ heart rate

♪
† ↑ stroke volume to provide more blood to
brain, muscles (and skin)
– Sympathetic autonomic response is catabolic.
 Skin because →
♪ Rx → running from a tiger need source of
♪ Eye →
 † Upper eyelid elevates to widen visual field raising my packed cell volume and that's a
† Pupils dilated → to see better nerve that can raise hematocrit

† Eyeball → protruded – called exophthalmos ♪ Urinary bladder

to see better. † Constrict internal sphincter
♪ † Internal is involuntary – controlled by
♪ Adrenal medulla autonomic nervous system

† Secrete epinephrine + nor epinephrine † External is somatic – under voluntary control.

† These ↑ heart rate and stroke volume to

constrict vessels and raise blood pressure. ♪ Git
♪ † Halt of peristalsis during fight or flight.
♪ Kidney → † Rx → flow of blood to git is averted to cns
† Secrete renin and skeletal.

† Renin convert angiotensinogen to angiotensin † (recall → o2 needed for energy – peristalsis

i is energy dependent)

† Angiotensin i converted to angiotensin ii ♪

† Angiotensin ii → two main functions ♪ Answer to question

 Constrict vessels and ↑ your blood ♪ Q– why do we have more sympathetic nerves
pressure. than parasympathetic

 Na+ retention → also raises blood pressure ♪ Because some organs only have sympathetic
nerve supply
♪ Penis
♪ Example → s organs
† No erection
† Skeletal
♪ Spleen
† Skin
† Storage organ of all blood lineages → red
blood cells white blood cells and platelets † Sweat gland

† During sympathetic response → ↑ release of † Spleen

blood cells into system by spleen increasing † Suprarenal gland ?
hematocrit value or packed cell volume ♪

† Hematocrit → ♪

 Blood made up of plasma and blood cells.

Video 6 – Sympathetic Response
 Def → volume of blood occupied by rbcs.
 Expressed as percentage of the volume of ϫ Sympathetic function region wise
the whole blood sample. Head and neck
 In 100 ml blood – 45 ml is occupied by rbc ♪ Cell bodies origin of preganglionic nfs →
 45 % of total blood volume is occupied by lateral horn spinal cord – t1 and t2
red blood cells called hematocrit. ♪ Relay → cervical ganglia of sympathetic chain
† Significance → ↑ rbcs → ↑ o2 delivery to ♪ Postganglionic sympathetic fibers in head and
tissues. neck → ciliary nerve.
† An example of a nerve that can raise – Sympathetic function in h & n →
hematocrit value → greater splanchnic nerve ♪ Eye →
 Sympathetic can contract spleen squeeze † Elevation of upper eyelid
blood out of it especially red blood cells † Mydriasis → dilation of pupil
 † Exophthalmos → protrusion of eyeball ♪

♪ Thorax
♪ Skin – ♪ Cell bodies origin of preganglionic nfs →
† Vasoconstriction of vessels to → lateral horn spinal cord – t1 to t4

 Shift flow of blood to heart and skeletal ♪ Relay → cervical and upper thoracic ganglia of
muscle. sympathetic chain

 To ↑ blood pressure ♪ From ganglia → arise post ganglionic fibers

postganglionic nerve (no nerve name
† Erection of piloerector muscles →
mentioned)
 Not prominent in humans but prominent in
– Sympathetic function in thorax →
animals such as cats their hair just
straighten ♪ Heart
♪ Salivary glands † Increase all cardiac properties
† Production of thick saliva † ↑ heart rate
† Thick saliva makes thirst → body replenishes † ↑ stroke volume
if has dehydration or cool down after running † Vasodilation of coronary vessels
from a tiger
♪ Lungs
† Maintain a robust blood pressure
† Bronchodilation
♪ Associated diseases → Horner syndrome
† ↓ in secretion
 Mn → letter S → S in HS – S in SANS.
♪
† Patho →
Abdomen
 Lesion in cell bodies of t1 and t2 (T1 to T3
♪ Cell bodies origin of preganglionic nfs →
in medicall) spinal segments → mcq
lateral horn spinal cord – t7 to t12
ž OR
♪ Relay → celiac and superior mesenteric ganglia
 Lesion in cervical ganglion of sympathetic of prevertebral chain (collateral chain)
chain mainly superior cervical ganglion.
♪ Postganglionic sympathetic fibers in abdomen
† Cause → lung cancer → cancer at apex of → greater splanchnic nerve.
lung.
† Mn → sympathetic in abdomen → greater
† CF → splanchnic nerve
ž all functions of SANS reversed. † Sympathetic in pelvis → lesser splanchnic
ž CF always Ipsilateral nerve
 Instead of elevation of upper eyelid → – Sympathetic function in abdomen
drooping of upper eyelid (ptosis) ♪ General → constrict all of vessels to direct
 Instead of mydriasis (dilation of pupil) → blood to heart and skeletal muscles
miosis – constriction of pupil. ♪ Gi tract
 Instead of exophthalmos – enophthalmos † Inhibits digestion or absorption
 Instead of sweating – anhidrosis ( warm ♪ Spleen
red skin) + facial flushing.
† Contracts to release more rbcs to ↑ o2
 Anisocoria → pupils of different sizes. carrying capacity of blood – this raises
† Location → ipsilateral hematocrit.
 If lung cancer on right side → horner’s ♪ Adrenal medulla
syndrome on right side. † Secrete epinephrine, norepinephrine and
 small amount of dopamine.  Descending sigmoid rectum
♪ Kidney † Internal sphincter → contracts so no urine
† Urine production is halted output.

† Raas system activated. † Internal is involuntary

† Liver ♪ Male copulatory organ

 Breakdown of glycogen into glucose. † No erection

 Also breakdown of fat into fatty acids –

Pelvis Sweat Glands

♪ Cell bodies origin of preganglionic nfs → ♪ Sweating is sympathetic response

lateral horn of spinal cord – t12 to l1 l2 ♪ Sweating ↑ during fight or flight.
♪ Relay → inferior mesenteric ganglia of † Normal sweating in a day → 600 to 800 ml
prevertebral chain (collateral chain) → mcq.
♪ Postganglionic sympathetic fibers in pelvis → – Piloerector Muscles
lesser splanchnic nerve + sacral nerve. ♪ Piloerector muscles in skin are innervated by
– Sympathetic function in pelvis sympathetic nervous system.
♪ Git – Stress Hormones

† Excretion inhibited. ♪ Activation of SANS → ↑ release of Cortisol.

† Occurs via contraction of → ♪ Cortisol is a stress hormone.
 Distal one third of transverse colon
–

–
–

–
 epinephrine/norepinephrine called → adrenergic
fibers.

– Neurotransmitter of nervous system ♪ Receptors for epinephrine/norepinephrine → α

and β receptors.
♪ Synthesis steps
† Phenylalanine →
† Tyrosine →
† Dopa →
† Dopamine →
† Norepinephrine →
† Epinephrine (epinephrine only synthesized in
adrenal medulla)
 Rx → adrenal medulla have enzyme pnmt
→ only enzyme capable to convert
norepinephrine to epinephrine.
 Postganglionic sympathetic fiber lacks
PNMT → can only norepinephrine.
♪ Site of synthesis → cell body of axon
♪ Site of storage and release → axon terminus

Preganglionic autonomic
♪ All preganglionic fibers of both sns and pns
secretes → acetylcholine ach
♪ Preganglionic fiber to adrenal medulla as well
Somatic
♪ Somatic fibers innervating skeletal muscles
secrete → acetylcholine ach
Postganglionic autonomic
♪ Post ganglionic of sympathetic secrete
→norepinephrine – ne
♪ Post ganglionic of parasympathetic secrete →
acetylcholine ach
♪ Adrenal medulla is ac a modified ganglion
† Fibers that it gives out are actually
postganglionic which secrete → ne +
epinephrine.

Neurotransmitter of sympathetic nervous system

† Epinephrine
† Nor epinephrine
♪ Fibers which secrete
 – Tip → vagus nerve supplies entire gi tract

♪ Storage → exception of upper end and lower end

† Granular vesicles ♪ Upper end (tongue and salivary glands ) →

supplied by nerves 7 and 9.
† They have a protein called granin.
♪ Lower end ( distal half of colon) → supplied by
♪ Release of norepinephrine
pelvic nerve.
† Action potential →
♪ Sacral → s2 – s4
† Calcium ions influx via voltage-gated
♪
calcium channel →
– Distribution
† Calcium is hero of contraction →
♪ Parasympathetic nervous system reach
† Exocytosis of NT
everywhere where sympathetic nervous system
♪ Recycling
reaches
† NE is recycled via reuptake
♪ Exception → are areas where only sympathetic
 Mn → NR – ns supplies
† Epinephrine is recycled via degradation by ♪ Skeletal muscle blood vessels
two enzymes
♪ Skin
 MAO → monoamine oxidase
♪ Sweat glands
ž Found at mitochondria of
♪ Spleen
‫ ؞‬Kidney
♪ Super renal gland aka adrenal gland
‫ ؞‬Liver
† This is why we have more sympathetic
‫ ؞‬Nervous system nerves than parasympathetic nerves
 COMT → no deets ♪

♪ Post ganglionic sympathetic fibers always ♪

secrete norepinephrine
– Sympathetic preganglionic fibers relay to
† Two exceptions sympathetic chain or collateral chain which lie in
 Sweat glands → have ACh receptors close proximity of spinal cord.
 Blood vessels supplying skeletal muscles ♪ Parasympathetic preganglionic fibers relay on
→ have ACh receptors terminal ganglia
♪ ♪ These ganglia embedded within wall of target
organ
Video 7 – Parasympathetic NS
♪ For instance ganglia from cranial
Background parasympathetic →
– Sympathetic is thoracolumbar † Ciliary ganglion for oculomotor nerve CN
– Parasympathetic is craniosacral III in head & neck.
♪ Involves cranial nerves 3 7 9 and 10 † Sphenopalatine and submandibular ganglia
† Mn → 1973 for facial nerve cn VII in head & neck.

†
† Otic ganglia for glossopharyngeal nerve cn
XI near ear.
♪ Because parasympathetic has less fibers relative
to sympathetic fibers → lateral horn of spinal † Ganglia for vagus nerve – CN X multiple &
cord in parasympathetic regions is not as lie in target organs of organ they supply.
prominent as sympathetic since less nerves  Mn 1973
come out. † Note → Pterygopalatine ganglion is also one
 of the 4 major Parasympathetic ganglion in † Anterior salivary glands i.e. Submandibular
head & neck and sublingual gland.
 However → mixed ganglion  Ganglia → submandibular ganglia.
 Contains both sympathetic & † Lacrimal glands
parasympathetic fibers.  Ganglia → sphenopalatine ganglion.
 Parasympathetic fibers → Facial nerve ♪

 Sympathetic fibers → sympathetic chain ♪ Note → minor salivary glands are glands that
from cervical region. suffer in sjogren’s syndrome
ž No idea why it is not mentioned by MP. ♪ Such as glands in lips
♪ Ganglia from sacral parasympathetic → ♪ Tongue
† S2 to s4 → pelvic nerve or pelvic splanchnic ♪ Buccal mucosa etc
nerve
–
† Ganglia embedded in wall of distal half of ♪ Glossopharyngeal nerve supplies →
colon. † Posterior one third of tongue
 Distal half includes → † Posterior salivary gland → parotid gland
ž Distal one-third of transverse colon † Ganglion → otic ganglion
ž Descending colon ♪

ž Sigmoid colon ♪ Vagus supplies →

ž Rectum and † Heart
ž Anal canal (some part only) above † Lungs
pectinate line
† Stomach
♪
† Small intestine – duodenum + jejunum +
♪ Below pectinate line → sensation is somatic it's ileum
not autonomic
† Colon
♪ This is why below pectinate line is sensitive to
† Ascending colon
pain because it's somatic sensory
† Proximal two-thirds of transverse colon
♪ Above pectinate line is autonomic is not
sensitive to pain but sensitive to stretch † Appendix

♪ That's why external hemorrhoids very painful † Cecum

♪ Internal hemorrhoids are not painful → only ♪ Since autonomic not sensitive to pain but
feel a stretch but not pain sensitive to stretch
♪
♪

– Parasympathetic functions

♪ Cn iii – oculomotor nerve →

† Miosis → pupillary constriction to minimize
light entering lens.
† Accommodation → of lens into spherical
rather than flat form.
♪ Cn vii – facial nerve supplies →
† Anterior two-thirds of tongue – chorda
tympani branch.
 † Mucus glands in respiratory tracts
 ↑ mucus secretions
 Rx → PNS is secretomotor.
♪ Heart
† Decrease all cardiac properties to conserve
energy
† ↓ HR – bradycardia
† ↓ SV
† Mechanism → mcq
 Muscarinic receptor activation in heart →
opening of K+ channels in SA node → K
efflux → hyperpolarization → ↓ HR.
† First sign of Cholinergic overdose →
Bradycardia → mcq.
♪ Eye
† Miosis → pupillary constriction
 Sympathetic dilate pupil through
♪
contracting dilator pupillae muscles (radial
muscles)
– Parasympathetic response is anabolic
 Parasympathetic constrict pupils by
♪ Builds glycogen from glucose → glycogenesis
constricting constrictor pupillae muscles
♪ Convert free fatty acids and glycerol into
(circular muscles)
triglycerides → lipogenesis

– Organ response during rest & digest

♪ Vessels
† Vasodilation
† Rx → parasympathetic is secretomotor →
vasodilation → more blood → more plasma
available for modification by different organs
to secrete

 Tears
 Saliva
 Gastric secretion
 Duodenal secretion
♪ Respiratory System
† Lungs
 Bronchoconstriction → rest & digest → ↓ † Accommodation → lens becomes more
breathing rate. spherical or near vision
 Increased bronchial secretions → to clear  Sympathetic accommodation → lens
out irritants. flattened for far vision.
  Mn → flat for far. Neurotransmitter of Parasympathetic n s
♪ Lacrimal gland † Ach
† Parasympathetic secretomotor ♪ Fibers which secrete acetylcholine →
† ↑ tear production from lacrimal gland cholinergic fibers.
♪ ♪ Receptors for ACh includes →
♪ Anterior two-thirds of tongue → submandibular  Nicotinic receptors
and sublingual cellular  Muscarinic receptors
♪ Nerve → seven † Nicotinic receptors → 2 subtypes
♪ Ganglion → submandibular ganglion  NN → donates Nicotinic receptors on
♪ Posterior 1/3rd autonomic neuron
♪ Nerve → glossopharyngeal ž All autonomic postganglionic fibers
♪ Parotid gland  NM → donates nicotinic receptors on
♪ Otic ganglion skeletal muscles

♪  Depolarization / activation

♪ ž Na influx

♪ Gastrointestinal tract † Muscarinic receptors → on involuntary

muscles.
† Salivary gland → ↑ saliva secretion.
 Location
 Secretion ↑ to digest and absorb
ž On Cardiac Muscles
† ↑ peristalsis
ž On GIT muscles
† Sphincter → relaxation of internal sphincter
ž On smooth muscles of blood vessels.
 Internal is involuntary
ž Sweat glands
 Mn → IN both.
ž Lacrimal Glands etc.
† Gallbladder → contracts to secrete secretions
to help digest and absorb.  5 sub types

– ž M1

♪ Urinary bladder ž M2

† Wall contraction ž M3

† Sphincter relaxation ž M4

♪
ž M5

♪ Copulatory organ ‫ ؞‬Only M1 M2 M3 functional →

Speed Pharmacology.
† Erection of penis in males
 Depolarization / activation (M1 M3 M5
† Erection of Clitoris in females.
only)
 Mechanism → dilation of penile or clitoral
ž Ca influx
arteries.

– Pearls

♪ Organ most affected by PNS → GIT

♪ Organ least affect by PNS → pupillary dilator
muscle.
–
 ‫ ؞‬Mn → p in plasma – p in
hepatocytes.
♪ Action of ach → localized – metabolized in
plasma.
 Action of NE is generalized
† Rx – once it reaches blood lead to dumbbells
which is fatal
♪ Receptor
† Acetylcholine acts on nicotinic and
muscarinic receptor
♪ Synthesis → † Nicotinic → receptors for Ach on autonomic
† Acetyl coa + choline → enzyme choline ganglia + NMJ of skeletal muscles.
acetyl transferase → ACh † Muscarinic → receptors for Ach on
♪ Site of synthesis → axon terminus involuntary muscles innervated by
† Ne synthesis → cell body of axon. parasympathetic NS.

♪ Storage → axon terminus

 Similar to ne
† Stored inside clear vesicles.
♪ Release of ach
† Action potential →
† Calcium influx via activation of voltage
gated calcium channel
† Exocytosis of nt
♪ Recycling →
† Acetylcholine is recycled via degradation
 Mn → AD – Ano Domini.
† Acetylcholine if not degraded → fatal
† Lead to → dumbbells
 Diarrhea
 Urination
Miosis + Muscle Weakness
Video 8 – Control of ANS


 Bradycardia
– Instead of control of ANS the Control centres in
 Emesis → nausea & vomiting CNS (brain + spinal cord) were discussed.
 Lacrimation – Control centres in brain
 Sweating ♪ Limbic system

† For emotions and behavioral reflexes

 Salivation
♪ Hypothalamus
† Degradation via enzyme acetylcholine–
† Mn → hypothalamus has all stats
esterase.
† Thermostat → regulates temperature
 Two types of acetylcholine–esterase † Glucostat → regulates glucose
ž True → location axon terminus † Appestat → regulates appetite

ž Pseudo → plasma & hepatocytes

  Patients with hypothalamic lesion you find them organ supplied by
morbidly obese or morbidly anorexic parasympathetic and exceptions in case of its
♪ Midbrain sympathetic especially sweat glands very few
♪ Center of reflexes. textbooks will also mention blood vessels of
† Coordinate reflexes of skeletal muscles skeletal muscles
† Light reflex ♪ Can add slide 11

† Superior colliculus → visual reflex – Pharmacology

† Inferior colliculus → auditory reflex ♪ All cholinergic muscarinic and adrenergic

 Mn → eyes are superior – ears are receptors have an agonists and antagonists
inferior. ♪ Agonist → stimulate receptor to increase its

♪ Pons function
† Micturition centres → Higher centres of ♪ Antagonist → decrease its function

micturition – control & influence Sacral ♪ Rest unimportant

micturition levels. †

♪ Medulla – Baroreceptors
† 4 centres ♪ Baro mean → pressure
 Two vital centres → cannot survive ♪ Receptors that sense pressure in aortic arch and
without. carotid sinus
 Two non vital centres → survive without. ♪ Baroceptor in carotid sinus → cn 9
† Vitals ♪ Baroreceptor in aortic arch → cn 10
 Cardiovascular center → essential for † Mn → ca mind made in class 9 10

heartbeat. ♪ Mechanism
 Respiratory center → essential to breathe. † Car accident – loss of blood → hypotension

† Two non vital. → baroreceptors signal brain of hypotension

 Swallowing centre → ↑ adh secretion to retain water +
 Vomiting centres sympathetic ans activated → epinephrine and
– Spinal cord centres. norepinephrine → ↑ heart rate + contractility
♪ Sacral centres → vasoconstrict arteries and veins to increase
† Micturition blood pressure to normal.
† Erection  Also → ↓ blood flow to kidney →
† Defecation juxtaglomerular complex secretes renin →
 Mn → MED convert angiotensinogen to angiotensin 1
→ converted into angiotensin 2
– Chemical transmitters of autonomic nervous  Angiotensin 2 → vasoconstrict arterioles +
system. secrete aldosterone to retain na + water.
♪ Imagine that your crazy professor said hey † Person has hypertension → vagus secrete ach

students stand up how many types of → ↓ heart rate + ↓ contractility to decrease →

cholinergic receptors do you know you should vasodilation of arterioles → decrease blood
answer professor with all due respect i know pressure to normal
two types eight has got two sides what do you †

mean two types nicotinic and muscarinic each ♪

has got two sides where do you find nicotinic – Sympathetic have 2 receptors  and 
cholinergic receptors at motor end plate also ♪ Why not one.
known as neuromuscular junction this is n sub ♪ Two receptors have two different functions
m but i can also find them in post-ganglionic ♪ In general
cell bodies oh you mean in ganglia exactly and †  → is excitatory
these are n sub n what's other type muscarinic †  → is inhibitory
 † Excitation means contraction †   1 cAMP activity → ↑ cardiac
† Inhibition means relaxation contractility
♪ Subtypes †  2 cAMP activity → relaxes smooth
† α1&α2 muscles.
† 1&2
♪  2 are tocolytic agent.
♪

– Rule 1 † lysis mean → inhibition

♪ α in general → excitatory † toco mean → Contraction
†  in general → inhibitory † Tocolytics → inhibit contraction of uterus.
Therefore, if pregnant patient having
♪  All tissues to be stimulated have α1
premature contraction before due time →
receptors EXCEPT
† Heart
administer  2 agonists aka tocolytic agent.
– Pharmacology
† JG complex of kidney (All hormones as per

MP) ♪  2 agonist causes hypokalaemia

♪ Used to treat hyperkalaemia
† Adipose cells (↑ lipolysis thus ↑ metabolism)
♪ mechanism
 They have  1 receptors
† stimulate sodium potassium ATPase, causing
 ↑ glycogenolysis since ↑ metabolism.
potassium influx → less potassium outside
– (a/c to an mcq →  1 blocker also inhibits
→ hypokalaemia
conversion of T4 to T3)
† beta 2 increases potassium uptake into
♪ All tissues to be inhibited have 2 receptors
smooth muscles → ↓ potassium in blood
EXCEPT
treating hyperkalaemia.
† Presynaptic neurons
– Norepinephrine vs epinephrine
† Platelets
♪  1 vs  2
† Insulin secreting cells of Pancreas ( & since
† Mn →
have  2 receptors are called  cells )
† One heart →  1
– Rule 2 † Two lungs →  2
♪ Alpha two and alpha one opposite of each other ♪ Muscarinic receptors
† alpha two → anti-sympathetic → † M1 in brain

 Brain more important than heart

 decreases norepinephrine release
† M2 in heart
 decrease sympathetic functions.
 SA node
† Alpha 1 → pro-sympathetic →  AV node
 increases all sympathetic functions. ž Predominantly ins SA node

ž SA node Receptors > AV node

– Second messengers of  & 
receptors.
♪  1 → since excitatory → Gq coupled
† M3 in rest of the body example
† Contraction need calcium therefore
 smooth muscle of eye
† Gq yields calcium
ž Sphincter
† Calcium is hero of contraction
ž Ciliary
♪  2 inhibitory → Gi coupled
 smooth muscle of lungs
♪ 
 smooth muscle of digestive tract
† All  subtypes → Gs coupled.
ž Stomach
† Gs coupled second messenger → ↑ cAMP. ž Intestine
† cAMP pathway → ž oesophagus
 contraction in heart (↑ cardiac properties)
 smooth muscle of Bladder
 relaxation in smooth muscles.
 smooth muscle of vessels
  exocrine glands converting epinephrine into inactive
ž sweat metabolites
ž salivary

ž Glands of stomach

ž Glands of Respiratory tract.

ž Lacrimal Gland


– Similarities epinephrine vs norepinephrine
♪ Both are hormones
♪ Both come from adrenal medulla

♪ Both are chemical transmitters

♪ Both are found in CNS ♪ Inactivation / Degradation / Recycling

– Differences epinephrine vs norepinephrine † Epi → degradation by COMT enzyme

♪ Only adrenal medulla can synthesize both NE +  COMT places a methyl group other than

E Normal position → degrades epinephrine

† Sympathetic nerve ending lacks enzyme † Norepinephrine →

PNMT which converts NE → E  Either recycled via Na+ dependent active

†  sympathetic post ganglionic nerve fibers reuptake into presynaptic ending via Nor
only synthesize NE. Epinephrine Transporter (NET)
♪ Adrenal medulla → secretion  Degraded by COMT in synaptic vesicle
ž Inside presynaptic membrane →
† epinephrine → 80 %

† Norepinephrine → 20 % ‫ ؞‬NE either degraded by MAO

♪ Chemical Differences ‫ ؞‬NE recycled to be used again.
† Epinephrine is simply methylated

norepinephrine.
† PNMT enzyme puts methyl group on

chemically normal position.

† NE lacks methyl in normal position.

† Methyl group transforms norepinephrine into

even more potent epinephrine.

♪ Methyl group comes from → methyl donor –
SAM.
♪ Steps
† Methylene THF → methionine

† Methionine → SAM .

♪ Methylation is a double-edged sword.

† It can add methyl group to end position,

giving epinephrine, or
† it can add a methyl group onto O position,

giving end product of epinephrine. ♪ Receptors Affinity

 PNMT enzyme add methyl group into † Epinephrine →  = 
normal position → converting epinephrine † Norepinephrine →  > 
into more potent epinephrine  More specifically → 1 > 2 > 1
 COMT enzyme aka catecholamine O  α → typically found on blood vessels.
(which means zero methyl transferase) ž Activation cause vasoconstriction → ↑

transfers methyl group into O position → total peripheral resistance or systemic

 vascular resistance → ↑ BP (diastolic
BP)
† Note → for ease of remembering – note rule

 Systolic blood pressure depends on cardiac

output.
 Diastolic blood pressure depends on
systemic vascular resistance aka
constriction in your vessels.
♪ Potency
† Epinephrine > nor epinephrine

 Rx → Methyl group on epinephrine makes

Epinephrine more potent.
 Rx 2 →
ž  receptors on heart – Central fibers
ž Epinephrine equal affinity for α &  – ♪ fibers before ganglia secrete ACh  cholinergic
while NE affinity α >  fibers
ž Heart more important & ♪ includes

ž   more important that  † fibers of skeletal muscle

ž  epinephrine is more potent because it † fibers of autonomic ganglia

acts more on  which is more † Fibers to adrenal medulla

important.  AM a modified ganglion

† Epinephrine is removed more slowly ♪ we disagree if i'm parasympathetic also create

relatively. acetylcholine hashtag cholinergic but if i am

♪ Second messenger sympathetic of secret nor adrenaline hashtag
† adrenergic with exception of sympathetic to
♪ Actions sweat glands these fibers secrete acetylcholine
† DOA of epinephrine → longer and stronger hashtag cholinergic so you have central fibers
† DOA norepinephrine weaker relatively. peripheral fibers central fibers some of them are
† somatic this is n sub m m for muscle some of
them are preganglionic autonomic receptor is n
♪
sub n for neuron because okay gluten is a
Video 9 – Cholinergic vs Adrenergic neuron so
– Peripheral Fibers
Cholinergic vs Adrenergic fibers ♪ Parasympathetic peripheral fibers secrete

acetylcholine  cholinergic.
– Cholinergic → fibers which secrete Ach
– Adrenergic → fibers which secrete NE. ♪ Sympathetic peripheral fibers secrete NE 
♪ All pre-ganglionic fibers secrete acetylcholine adrenergic fibers.
† 2 exceptions of Sympathetic secrete Ach on
called  cholinergic fibers.
 Sweat glands
♪ All post-ganglionic parasympathetic secrete
 Smooth muscles of the heart
acetylcholine called cholinergic
– Receptors for fibers
♪ All post ganglionic sympathetic secrete
♪ cholinergic fibers receptors include →
norepinephrine  called adrenergic.
† Nicotinic receptor

† Muscarinic receptor

♪ Adrenergic fibers receptors include

† Alpha
 † Beta † Gi tract because actually parasympathetic in
Gi tract is not inhibitory it's stimulatory it's
going to require Gq not Gi just in case you
Video 10 – Acetylcholine vs Nor-Epinephrine
were wondering
– No need – points already covered in previous. †

– Rule → to learn remember muscarinic receptors

are for parasympathetic
Video 11 – Nicotinic vs Muscarinic
– M1 → brain
Muscarinic Receptors ♪ Rx → brain most important
– Ach – M2 heart

♪ Fibers which secrete acetylcholine → ♪ Heart is second most important

cholinergic fibers. ♪ Decrease firing of sa node and av node →
♪ Receptors for ach includes → † ↓ heart rate
 Nicotinic receptors † ↓ contractility
 Muscarinic receptors  SA node → lengthens depolarization
– Muscarinic receptors → on involuntary muscles  AV node → ↑ AV nodal delay.
♪ Location – M1 and M3
† On cardiac muscles ♪ Are present on Acinus glands → glands
† On git muscles involved in secretions.
† On smooth muscles of blood vessels. † ↑ Gastrointestinal secretion
† Sweat glands † ↑ Tear production
† Lacrimal glands etc. † ↑ Saliva production
♪ 5 sub types † ↑ Bronchial secretions
† M1 † ↑ Sweat production.
† M2 – M3 → Eye

† M3 ♪ Contract sphincter papillae muscles → miosis

† M4 ♪ Contraction of ciliary muscle → causing
† M5 accommodation for near vision.

♪ G protein coupling – M3 → Lungs

† M1 M3 M5 → Gq coupled → stimulatory in ♪ ↑ secretion

function. ♪ ↑ contraction of bronchi → bronchospasm
 Stimulation of Gq → ↑ intracellular Ca – M3 → GI tract

 Ca mother of contraction ♪ ↑ contraction of smooth muscles if gi tract

 ↑ intracellular contraction bring about ♪ ↑ gastric secretion
contraction of smooth muscles. ♪ This ↑ digestion absorption
† M2 M4 → Gi coupled → inhibitory in – M3 → blood vessels
function
♪ Relaxation of smooth muscles of vessels →
 Stimulation of Gi → opening of K+ vasodilation
channels → ↑ intracellular K+
 ↑ intracellular K+ → hyperpolarization →
Some pharmacology
↓ of HR
– Drugs can act on all receptors → † beta agonist
♪ Agonist on nicotinic receptors † beta blocker.
♪ Antagonists on nicotinic receptors ♪ alpha and beta agonists.
† Antagonists on NM → neuromuscular † Norepinephrine can act on
blockers. † alpha one
† Target for anesthesiologists. † alpha two.
† Paralysis of skeletal muscles. †  one
♪ Agonists on muscarinic receptors † α 2 → anti-sympathetic
♪ Antagonists on muscarinic  decreases release of norepinephrine.
♪ Alpha agonists † α 1 → pro-sympathetic.
♪ Alpha blockers (blockers)
♪ beta receptors,
♪ Beta agonists
† beta 1 → heart
♪ Beta blockers (blockers)
† beta 2 → bronchi
♪
† beta 3 → lipolysis.
Video 12 – Epinephrine Vs NE ♪ Epinephrine and NE are mixed Adrenergic
medications.
– Intro
♪ act on both α and  receptors.
♪ upper limit → systolic blood pressure
♪ Norepinephrine
♪ lower limit → diastolic blood pressure
♪ agonist on both α and  ,
♪ in middle → mean arterial blood pressure
♪ Affinity → α1 > α2 > 1
† Slightly closer to diastolic pressure because
♪ α1 .
formula for MABP →
 2/3 DBP + 1/3 SBP † constricts arteries → ↑ afterload → ↑
diastolic BP.
♪ after receiving drug compared to base line →
see pic ♪  1.

† systolic blood pressure increased † increase all cardiac properties.

† diastolic blood pressure increased † ↑ HR ↑ SV ↑ CO

† MABP ↑ † When you increase heart rate and

contractility → systolic blood pressure
† heart rate → bradycardia.
increases.
– Pharmacology
† Also don't forget that alpha 1 will squeeze
♪ These can be tweaked via your veins, increasing your preload, which
† nicotinic agonist will increase also your systolic blood
† nicotinic antagonist pressure. So here we have increased systolic
† muscarinic agonist blood pressure and increased diastolic blood
pressure. But rise in systolic was greater than
† muscarinic antagonist.
rise in diastolic and that's why your
† agonists,
♪
† direct agonist
† In essence α 1 activity will ↑ mean arterial
† indirect agonist.
blood pressure as both systolic pressure &
† alpha agonist diastolic pressure increase.
† alpha blocker ♪
 † If there is increased mean arterial blood norepinephrine cannot be reversed because
pressure as a negative feedback as a norepinephrine lacks beta 2.
baroreceptor reflex, you can experience † Now this is most important slide in entire
reflux bradycardia. You can thank Vegas and stinking video. Epinephrine is dose
M2 receptors. This is parasympathetic. dependent,
What's gonna happen to my heart rate? It
♪ at low dose
depends. Your heart rate just by beta 1 can go
† beta 1 and beta 2
up. By reflex, bradycardia can go down, so
it's just a matter of who wins. † 1 increase heart rate and contractility, →
increasing systolic blood pressure.
– Epinephrine

♪ Also acts on both α and  receptors †  2 dilate vessels → decreasing diastolic

blood pressure
♪ Affinity → equal agonist – α = 
† decrease in diastolic greater than increase in
♪ Epinephrine dose dependent affinity
systolic →  mean blood pressure will drop
† At low dose → Affinity –  1 =  2 agonist, slightly.
† At high dose, epinephrine acts as NE † pulse pressure – Def → difference between
 Affinity – α1 > α2 > 1. systolic and diastolic,
†  1 agonist → ↑ all cardiac properties.  increase dramatically.
 increase systolic blood pressure. ♪ At high dose.

†  2 dilate vessels, ↓ systemic vascular † Same as NE

resistance, ↓ diastolic blood pressure → ♪ At intermediate dose
overall decreasing blood pressure. † α 1 and  2
♪ How to differentiate between epinephrine and  both of them hate each other.
NE since they are almost same?
† α 1 activity → constrict vessels → increase
† Difference → hypertension caused by your diastolic blood pressure.
epinephrine can be reversed
 Constriction also ↑ preload → ↑ systolic
 hypertension caused by NE cannot be blood pressure.
reversed.
†  2 → dilate vessels and decrease diastolic
† Give alpha 1 blockers to each one of them.
blood pressure.
 If you give alpha one blocker to
† And actually Beta 2 has one. Alpha 1 will
epinephrine system, ONLY alpha one
say, okay, I'm gonna constrict your veins,
blocked → Epinephrine still work on beta
increasing your preload and increasing your
two → inhibit vasoconstriction → lower
systolic blood pressure. Beta 1 will agree
blood pressure → reversing hypertension.
with that and also increase your systolic
† alpha one blocker to NE. blood pressure.
 NE no activity on  2 † End result → systolic increased
  2 stimulation → vasodilation d  diastolic decreased
 α 1 inhibited  mean blood pressure has remained same.
 But  2 not stimulated → No dec in BP → † heart rate
NE never lower blood pressure.  beta 1 can increase heart rate.
 That's why hypertension caused by † No reflex bradycardia
epinephrine can be reversed with alpha † No reflex tachycardia?
one blockers, while hypertension of
– Epinephrine and norepinephrine clinical uses.
 † cardiac arrest → intravenous epinephrine/NE deamination
 Intramuscular slower than intravenous – Catabolism of thyroid hormones → deiodination

† heart block or AV nodal block (when heart – Catabolism of TSH demethylation.

rate is very slow) → epinephrine / NE ♪

† as adjunct to local anesthetics. → ♪

epinephrine/ NE constrict vessels → local

ϫ Pearls
anesthetic remain in that local location for a
longer period of time, prolonging effect of – Pheochromocytoma →
local anesthesia. Perfect. We can use them if ♪ Tumor of adrenal medulla → ↑ Epi + NE.
you have hypotension or a shock. ♪ Tx → α +  blockers
– Only Epinephrine uses ♪

♪ Cardiac Arrest → epinephrine ♪

♪ Anaphylactic shock (Type 1 HSR) → ϫ

epinephrine. Video x – Parasympathetic NS
♪ Severe asthma attacks (known as status
asthmaticus) → Epinephrine only PNS

† Remember from EpiPen Diaphragm muscle

† There is no norepinephrine pen → Rx → NE Chief muscle of respiration.
not that potent.
♪
– Both Epi + NE uses

♪ Hypotensive shock → epinephrine.

–

– Question, does epinephrine help people with

hereditary angioedema?
♪ Answer not really.
♪ anaphylactic reactions caused by histamine.
And that's why anti histamines medicines
administered.
† Also Epinephrine prevents further release of
histamine.
♪ Hereditary angioedema → problem is not
histamine, problem is bradykinin.
♪ epinephrine not helpful. Bradykinin inhibitors
are DOC.
ϫ
Video 13 – Alpha vs Beta

– Points added where needed.

ϫ Pearls
– Catabolism (recycling) of Epinephrine →