Peripheral Nervous System

Question 1

Receptor structure classification of sensory receptors

Answer 1

Special sense receptors

General sense receptors

• Non-encapsulated (free) nerve endings. Respond to temperature and pain and itching. Tactile (Merkel) Disks. Hair follicle receptors.
• Encapsulated nerve endings. Tactile corpuscules, lamellar corpuscules, bulbous corpuscules, muscle spindles, tendon organs, joint kinesthetic receptors.

Question 2

Location classification of sensory receptors

Answer 2

Extero receptors

Intero receptors

Proprioreceptors

Question 3

Stimulus type classifications of sensory receptors

Answer 3

Mechanoreceptors

Thermoreceptors

Chemoreceptors

Photoreceptors

Nociceptors

Question 4

Cranial nerves

Answer 4

Mostly serve head and neck. 12 pairs, numbered I - XII. Numbered by function. eg - 1 is olfactory (smell). 2 is the optic nerve (vision).

Question 5

Components of a reflex arc

Answer 5

1 - receptor
2 - sensory neuron (to the PNS)
3 - interneuron (in the PNS)
4 - motor neuron (from the PNS)
5 - effector

Question 6

Spinal nerves

Answer 6

Labelled similar to vertebrae.
Cervical (C) Thoracic (T) Lumbar (L) Sacral (S) Coccycal (Co).
The Phrenic nerve (in C) for respiration.
Sciatic nerve (starts in L and goes down)

Question 7

Significant reflexes and tests

Answer 7

Knee-jerk or patellar reflex.

Plantar reflex - curling toes. If the Plantar reflex is faulty - Babinski’s sign - big toe goes up, other toes spread

Question 8

Gate Control Theory of Pain

Answer 8

• Nociceptors send nerve impulses up a small nerve channel. Gates open, positive ions rush in, experience pain.
• Other receptors (mechano-, thermo-, etc, send impulses up large nerve channels. Open large channel closes the smaller pain channel.
• Theory is that if you massage a patient, warm them, sooth them, the ‘pain gates’ close.

Question 9

Components of the Nervous System

Answer 9

Central Nervous System and Peripheral Nervous System (PNS)
From the PNS, branches of sensory neurons and motor neurons.
From motor neurons, branches of somatic (voluntary) and autonomic (involuntary).
From autonomic, branches of sympathetic (mobilises for emergency) and parasympathetic (conserves energy)

Question 10

Dermatomes

Answer 10

Sections of skin that relate to specific nerves.