7

Question 1

Pain sensation

Answer 1

Is not due to over stimulating of other sensations
Pre potent stimulants

Question 2

Receptors Pain

Answer 2

free nerve endings Types:

Question 3

Mechanism of stimulation of pain receptors

Answer 3

They are stimulated by tissue damage
which release certain substances as
bradykinin, histamine, prostaglandin,
acids, excess K+ ions & serotonin.

Question 4

Types of Cutaneous Pain

Answer 4

1- Fast pricking type of pain :
a-Well localized.
b-Conducted in A delta fibers
c-Inform the person very rapidly about the
damaging stimulus to start protective reflexes.
2- Slow burning pain : a-Poorly localized.

Question 5

Reactions to cutaneous pain

Answer 5

1-Somatic effects : In the form of protective withdrawal reflexes
2-Autonomic effects Mild or moderate pain results in sympathetic effects in the form of Tachycardia & Rise of arterial blood pressure
Sever pain results in parasympathetic effects produced as bradycardia & and hypotension

Question 6

Deep pain
Origin: Afferent Nature Localization Causes

Answer 6

Origin: pain receptors in the deep structures as muscles , ligaments, joints and periosteum
of bones
Afferent: non myelinated C- fibers
Nature: dull aching.

Question 7

Visceral pain
Origin: Afferent Nature Localization Causes

Answer 7

Origin internal viscera

Nature colicky, dull

Afferent non myelinated C fibers

Localization poorly

Question 8

Associated changes
Deep pain

Answer 8

1- Somatic changes: spasm of nearby skeletal muscles.
2- Autonomic reactions: parasympathetic to
decrease heart rate & blood pressure. 3- Emotional reactions: anxiety, fear, crying & depression

Question 9

Causes of visceral pain

Answer 9

1 - Ischemia of viscera by

Question 10

Headache
Renal pain,
Uterine and labor
Appendicular
Angina pain
Gall Bladder pain,

Answer 10

Headache : surface of the head
Renal pain, : testis loin
Uterine and labor : The back
Appendicular :umbilical ,epigastrium
Angina pain: little finger medial side of the left arm, Jaw or root the neck, retro sternum
Gall Bladder pain,: right shoulder

Question 11

Mechanism of referred pain

Answer 11

1-Convergence projection theory: Afferent pain fibers from the skin area and the diseased viscera converge on the same second order neuron and finally stimulate the same cortical neuron.
2-Facilitation theory Visceral pain afferent fibers send collaterals to
facilitate the second order neuron of pain
pathway from the skin area of reference
facilitating the pain sensation from this area

Question 12

Pain control system

Answer 12

1-Stress analgesia
2-The pain felt from an injured area is reduced when the skin around the injured area is rubbed or stroked
3-Morphine injected in minute doses
experimental animals in the third ventricle of the brain produce marked analgesia

Question 13

Types of pain control systems:

Answer 13

1- Supra spinal pain control system.

2- Spinal pain control systems.

Question 14

Opiate receptors

Answer 14

They are 4 types
1- Mu receptors
2- Delta receptors
3- Kappa receptors
4- Sigma receptors

Question 15

each type is more sensitive to special type of internal opioids which are:

Answer 15

A

Some of theses transmitters are secreted by
pituitary gland and hypothalamus during
stress.

A Enkephalins B- Endorphins (Beta endorphins) C- Dynorphin

Question 16

Sites of opiate receptors

Answer 16

a- Periventricular structures of the third ventricle
b-Periaqueductal gray matter in midbrain and pons
c- Substantia nigra d- Dorsal raphe nucleus of the medulla
Electrical stimulation of the above areas produce marked analgesia

Question 17

Gate theory of pain:

Answer 17

The cells of the SGR in layer II of the cord gray matter act as a gate through which pain impulses reach the lateral spinothalamic tract

Question 18

Spinal pain control systems.

Answer 18

1- Collaterals from large myelinated A beta fibers of touch sensation end on the central termination of the C fibers and produce pre-synaptic inhibitory transmitter (GABA ) which inhibit the release of substance P.
2- fibers that carry pricking pain end on neurons inlayer I of the cord gray matter and send collaterals that end around inter-neurons between layers I andII. These neurons produce inhibition of cells of SG of
sor rolandi through the release of enkephalins.

Question 19

Supraspinal pain control system

Answer 19

1- Opioid receptors combine with opioid peptides,an Enkeph. from pituitary and hypothalamus as well
as exogenous morphine leading to their stimulation
2- the stimulation areas send impulses to the Medullary raphe nucleus which, in turn send impulses to activate inhibitory inter-neurons in the cord (the chemical transmitter is serotonin).
3-The stimulated interneurons release enkephalin between layer I and II of the gray matter of the as
cord to inhibit the neurons of the S.G.R.
thus, transmission of pain impulses is inhibited.
g