CHAPTER 4 Pharmacology

WHAT IS THE DIFFERENCE BETWEEN CNS AND PNS?

The brain + the spinal cord –The center of integration and control The nervous system outside of the brain and spinal cord Consists of: –12 Cranial nerves »Carry info to and from the brain –31 Spinal nerves »Carry info to and from the spinal cord 2 divisions: 2A. Somatic Nervous System (SNS) (voluntary) 2B. AUTONOMIC NERVOUS SYSTEM (ANS) (involuntary) --> *SANS & **PANS It is divided into 2 MAJOR categories:

DOES THE PNS CONTAIN SENORY, MOTOR OR BOTH?

THE PNS USE NEURONS THAT ARE SPECIALIZED TO CONDUCT INFORMATION FROM ONE PART OF THE BODY TO ANOTHER. BOTH

PNS – WHAT DOES THE SOMATIC NERVOUS SYSTEM CONTOL?

CONTROLS VOLUNTARY SKELETAL MUSCLE CONDUCTS SENSORY INFORMATION FIBERS PASS FROM SPINAL CORD DIRECTLY TO THE STRIATED MUSCLES VOLUNTARY MUSCLE

IS THE ANS VOLUNTARY OR INVOLUNTARY

AUTOMATIC MODULATING THE ANS FUNCTIONS AS AN AUTOMATIC MODULATING SYSTEM FOR MANY BODILY FUNCTIONS. IT IS THE PART OF PNS CONSISTING OF MOTOR NEURONS THAT CONTROL INTERNAL ORGANS. IT CONTROLS THE BODY’S ACTIVITIES THAT YOU DON’T THINK ABOUT: INVOLUNTARY INVOLUNTARY

WHAT IS THE FLIGHT AND FIGHT RESPONSE?

shocks physiologic processes into action during environmental and internal stress copes with sudden emergencies SANS -

WHAT IS MYDRIASIS?

DILATED PUPILS

The afferent (sensory) fibers say: “Hey…What’s happening?” The central integrating areas exclaim: “Let’s coordinate all this info! Hey what did you find out?” PREGANGLIONIC POSTGANGLIONIC While, the efferent (peripheral) motor PREGANGLIONIC & POSTGANGLIONIC fibers could respond like: “Begin sweating! Heart begin palpitating!”

WHAT IS THE SPACE BETWEEN THE PREGANGIOLIC AND POSTGANGLIONIC FIBERS?

The postganglionic neuron originates in the ganglia and innervates the effector (or target) organ or tissue THE SYNAPSE AREA

ARE PREGANGLIONIC FIBERS LONG OR SHORT?

PREGANGLIONIC FIBERS OF THE PANS ARE RELATIVELY LONG AND EXTEND NEAR TO OR INTO THE INNERVATED ORGAN, WHICH LEADS TO A DISCRETE RESPONSE POSTGANGLIONIC FIBERS, ORIGINATING IN GANGLIA (GANGLION/SYNAPSE), ARE USUALLY SHORT AND TERMINATE ON THE INNERVATED TISSUE LONG

NOTE: there is a difference in the length on the preganglionic fibers in the SANS vs the PANS In the SANS it is OPPOSITE: –Pre-ganglion fiber is short –Post-ganglion fiber is long Post-ganglion fibers will terminate at the effector organ or tissue

WHAT ARE PARASYMPATHOMIMETIC AGENTS?

1. Cholinergic (parasympathomimetic) agents  Classified as either direct or indirect acting agents.  Direct acting drugs act directly on the parasympathetic receptors (Eg. Pilocarpine acts on Nicotinic).  Indirect acting drugs either cause release of neurotransmitter which then goes to the receptor site OR they inhibit the enzyme cholinesterase (EG: Sarin (nerve gas) HAS no therapeutic use; it was used on a subway in Japan to poison riders) Table 4-3, p.39

WHAT IS BRADYCARDIA?

DECREASED HEARTRATE

WHAT DRUG IS USED IN PARKINSONS DISEASE?

An anticholinergic drug such as benztropine (Cogentin) reduce the tremors and rigidity associated with Parkinson and drug-induced Parkinson disease used occasionally in combination with levodopa COGENTIN

WHAT IS USED TO TREAT MOTION SICKNESS?

Scopolamine (CNS depressant action) is used to treat motion sickness SCOPOLAMINE

WHAT ARE THE NEUROTRANSMITTERS IN SANS?

1. EPINEPHRINE: IS RELEASED WITH STIMULATION FROM THE ADRENAL MEDULLA AND DISTRIBUTED IN THE BODY VIA THE BLOOD 2. NOREPINEPHRINE (NE): MAJOR TRANSMITTER RELEASED AT THE TERMINAL ENDINGS OF THE SANS 3. DOPAMINE: RECEPTORS ARE IMPORTANT IN THE BRAIN AND SPLANCHNIC AND RENAL VASCULATURE

WHAT ARE ADRENERGIC AGENTS USED FOR IN DENTISTRY?

Used in dentistry for their vasoconstrictive actions (hemostasis) on blood vessels. Added to local anesthetics to prolong the action of the LA, to reduce the risk for systemic toxicity, and to help to create a dry field. VASOCONSTRICTION

WHAT IS EPINEPHRINE REVERSAL?

Adrenergic Blocking Agents Clients pretreated with α-adrenergic blocking agents and then given epinephrine exhibit a predominance of beta effects (vasodilation), which lowers BP This is called EPINEPHRINE REVERSAL because BP goes down rather than up α-adrenergic blocking agents