week 14- pain

Question 1

Nociceptors:

Answer 1

• sensory pain receptors activated by noxious insults to peripheral tissues
• Transmit stimuli into action potentials transmitted through spinal cord

Question 2

transduction

Answer 2

nociceptors are stimulated by a noxious stimulus, and the injured tissue then releases neurotransmitters. These neurotransmitters propagate an action potential along the afferent nerve fibres to the spinal cord.

Question 3

transmission

Answer 3

impulses are transmitted to the CNS via specialised sensory (afferent) fibres. These are either myelinated A fibres (with greater conduction velocity resulting in fast pain) or unmyelinated C fibres (slower onset and longer duration). The majority of pain sensations travel via the C fibres, creating more of an emotional response.

Question 4

Perception

Answer 4

this occurs when there is an awareness and interpretation of pain sensations in the brain. Perception can be described in terms of pain threshold (the level of painful stimulation required for perception), and pain tolerance (the degree of pain one is willing to bear before seeking relief). Pain tolerance varies according to psychological, familial, cultural and environmental factors.

Question 5

Modulation

Answer 5

there is modulation of pain signals at multiple sites along the pain pathway, with descending pathways from the brain stem to the spinal cord producing a third set of neurotransmitters acting to slow or impede the pain impulse. The modulation process also involves the endogenous (from within the body) release of analgesia.