1. PERCEPTION &
COORDINATION

2. Sympathomimetics
• Drugs that stimulate the sympathetic nervous
system and mimic the sympathetic
neurotransmitters
(norepinephrine, epinephrine).
• They act on one or more adrenergic receptors
sites located on the cells of smooth muscles
such as the heart, bronchiole
walls, gastrointestinal tract, urinary
bladder, and ciliary, muscle of the eye.
The Anatomy & Physiology
of the nervous system

3. Sympathomimetics
Classification
The Anatomy & Physiology
of the nervous system

4. Sympathomimetics
Epinephrine
• Administered SC, IV, topically, or by inhalation. It is
not to be given orally as it is metabolized quickly in
the GI tract resulting to inadequate serum levels.
• It is frequently used in emergencies to combat
anaphylaxis.
• It is a potent inotropic drug that causes the blood
vessels to constrict; thus blood pressure
increases, the heart rate increases, and the bronchial
tubules dilate.
The Anatomy & Physiology
of the nervous system

5. Sympathomimetics
Albuterol Sulfate (Proventil, Ventolin)
• Selective beta2 adrenergic receptor
agonist which response is bronchodilation.
• Used primarily in asthmatic patients
The Anatomy & Physiology
of the nervous system

6. Sympathomimetics
Isoproterenol HCl
• Activates both beta1 and beta2 receptors.
It is more specific than epinephrine
becauseit acts on two different adrenergic
receptors but is not completely selective.
• Used to control asthma
The Anatomy & Physiology
of the nervous system

7. Sympathomimetics
Clonidine (Catapres) and Methyldopa
(Aldomet)
• They are selective alpha2 adrenergic drugs
that are used primarily to treat
hypertension.
• They regulate the release of
norepinephrine by inhibiting its release.
• They cause cardiovascular depression by
stimulating alpha2 receptors in the CNS
leading to a decrease in blood pressure.
The Anatomy & Physiology
of the nervous system

8. Sympatholytics
• Drugs that block the effects of the
adrenergic neurotransmitters. They act as
antagonists to the adrenergic agonists.
• Inhibits the release of the
neurotransmitters norepinephrine and
epinephrine.
The Anatomy & Physiology
of the nervous system

9. Sympatholytics
Alpha-Adrenergic Blockers
• Drugs that block or inhibit a response at
the alpha-adrenergic receptor site.
• They are divided into 2 groups: selective
alpha-blockers (those that block alpha1)
and nonselective alpha-blockers (those
that block alpha1 and alpha2).
The Anatomy & Physiology
of the nervous system

10. Sympatholytics
Beta-adrenergic Blockers
• These drugs cause a decrease in heart rate
and a decrease in blood pressure.
• They are divided into 2 groups: selective
beta-blockers (those that block beta1) and
nonselective beta-blockers (those that
block beta1 and beta2).
The Anatomy & Physiology
of the nervous system

11. Sympatholytics
Adrenergic Neuron Blockers
• Drugs that block the release of
norepinephrine from the sympathetic
terminal neurons.
• Its clinical use is to decrease blood pressure.
They are potent antihypertensive agents.
• Examples of this drugs are guanethidine
monosulfate (Ismelin) and guanadrel sulfate
(Hylorel).
The Anatomy & Physiology
of the nervous system

12. Parasympathetic Nervous System
• The parasympathetic system dominates
control of many visceral effectors under
normal, everyday conditions.
• The ANS is responsible for regulation of
internal organs and glands, which occurs
unconsciously.
The Anatomy & Physiology
of the nervous system

13. Parasympathetic Nervous System
• The two types of receptors are
1. muscarinic receptors - stimulates the
smooth muscles and slow heart rate
2. nicotinic receptors - stimulates skeletal
muscles for contraction
The Anatomy & Physiology
of the nervous system

14. Parasympathetic Nervous System
STRUCTURE
• Parasympathetic
preganglionic neurons –
dendrites and cell bodies
are located in the gray
matter of the brainstem and
the sacral segments of the
spinal cord.
The Anatomy & Physiology
of the nervous system

15. Parasympathetic Nervous System
STRUCTURE
• Parasympathetic
preganglionic neurons –
axons extend some
distance before
terminating in the
parasympathetic ganglia
located in the head and in
the thoracic and
abdominal cavities close
to the visceral effectors
that they control
The Anatomy & Physiology
of the nervous system

16. Parasympathetic Nervous System
STRUCTURE
• Parasympathetic
postganglionic neurons –
dendrites and cell bodies
lie in the outlying
parasympathetic
ganglia, and their short
axons extend into the
nearby structures.
The Anatomy & Physiology
of the nervous system

17. Autonomic Neurotransmitters
The Anatomy & Physiology
of the nervous system

18. PNS Neurotransmitters
(Postganglionic Neurons-Effectors}
• Acetylcholine
• 2 Types of Receptors
a) Muscarinic – stimulates smooth muscles
(Cardiac Muscle)
b) Nicotinic – stimulates skeletal muscles
(neuromuscular)
The Anatomy & Physiology
of the nervous system

19. Parasympathetic Responses
The Anatomy & Physiology
of the nervous system

20. Parasympathomimetics
(Cholinergics)
• These are drugs that stimulate the
parasympathetic nervous system.
• They mimic the parasympathetic
neurotransmitter acetylcholine.
The Anatomy & Physiology
of the nervous system

21. Parasympathomimetics
Classification
The Anatomy & Physiology
of the nervous system

22. Parasympathomimetics
Direct-Acting Cholinergics
Bethanicol Chloride, Metoclopramide
HCl, Carbachol
• They are primarily selective to the
muscarinic receptors and are nonspecific
because the muscarinic receptors are
located in the smooth muscles of the GI
and genitourinary tracts, glands, and the
heart.
The Anatomy & Physiology
of the nervous system

23. Parasympathomimetics
Direct-Acting Cholinergics
• Eye: pilocarpine
• These drugs constricts the pupils of the
eyes thus opening the canal of Schlemm to
promote drainage of aqeous humor. This is
used to treat glaucoma by relieving fluid
(intraocular) pressure in the eye.
The Anatomy & Physiology
of the nervous system

24. Parasympathomimetics
Classification
The Anatomy & Physiology
of the nervous system

25. Parasympathomimetics
Indirect-Acting Cholinergics
• demecarium bromide, echothiophate
iodide, isoflurophate
• These group of drugs do not act on
receptors, instead they inhibit or inactivate the
enzyme cholinesterase, thus permitting
acetylcholine to accumulate at the receptor
sites. Thus they are called cholinesterase
inhibitors or anticholinesterases.
The Anatomy & Physiology
of the nervous system

26. 2 Types of Indirect-Acting
Cholinergics
Reversible Cholinesterase Inhibitors
• Ex. ambenonium chloride, edrophonium
chloride
• These drugs are used
1. to produce papillary constriction in the treatment
of glaucoma
2. to increase muscle strength in clients with
myasthenia gravis.
The Anatomy & Physiology
of the nervous system

27. 2 Types of Indirect-Acting
Cholinergics
Irreversible Cholinesterase Inhibitors
• Ex. neostigmine, neostigmine
methylsulfate, pyridostigmine bromide
• These are potent agents because their effect
are long lasting. With irreversible inhibitors the
bond between the irreversible cholinesterase
inhibitor and cholinesterase are permanent.
The Anatomy & Physiology
of the nervous system

28. Parasympatholytics
(Anticholinergics)
• Drugs that inhibit the actions of
acetylcholine by occupying the
acetylcholine receptors.
• The major responses to anticholinergics
are a decrease in GI motility, a decrease
salivation, dilation of pupils
(mydriasis), and an increase in pulse rate.
The Anatomy & Physiology
of the nervous system

29. Parasympatholytics
(Anticholinergics)
The Anatomy & Physiology
of the nervous system

30. Parasympatholytics
(Anticholinergics)
Atropine
• Atropine acts on the muscarinic
receptor, but they have little effect on the
nicotinic receptor.
The Anatomy & Physiology
of the nervous system

31. Parasympatholytics
(Anticholinergics)
Atropine
Uses of Atropine
1. Pre-operative medication to decrease salivary
secretions
2. Antispasmodic drug to treat peptic ulcers
because it relaxes the smooth muscles of the GI
tract and decreases peristalsis
3. Agent to increase the heart rate when
bradycardia is present.
4. This can also be given as an antidote for
muscarinic agonist poisoning.
The Anatomy & Physiology
of the nervous system

32. Disorders of the Autonomic Nervous
System
1. Stress-Induced Disease
– Heart Disease
– Digestive Problems
– Reduced resistance to disease
2. Neuroblastoma
– is a malignant tumor of the sympathetic
nervous system.
–Occurs in the developing nervous systems of
young children and metastasizes rapidly to
other parts f the body.
The Anatomy & Physiology
of the nervous system