Anatomy Bones and Muscles · MU Pleven

144. Functional systems (Pathways) in the CNS. Systems of common sensitivity – system for touch and pressure (exteroception).

Explains the extroceptive system that detects mechanical stimuli such as touch, pressure, vibration and proprioception, tracing the route from mechanoreceptors such as Merkel cells and Meissner's corpuscles through peripheral nerves, the spinal cord dorsal horn, the dorsal column-medial lemniscus pathway, the brainstem and thalamus to the primary somatosensory cortex. It closes by contrasting general somatic and visceral afferents with the special senses.

Inside: 3 sections · 2 labelled pictures · 10 flashcards · 1 min

Topic 143 of 236 in the MU Pleven syllabus for Anatomy Bones and Muscles (Medicine, Year 2). The free AceMed note covers it in 3 sections, about 177 words (1 min of reading), with 10 flashcards.

In this note

  1. EXTROCEPTIVE SYSTEM FOR MECHANORCEPTION
  2. Components :
  3. 2 Types of sensory system :

EXTROCEPTIVE SYSTEM FOR MECHANORCEPTION

  • Means the structures and pathways that detect mechanical stimuli from the external environment providing information about touch , pressure , vibration & proprioception.

Components :

1. Sensory receptors (mechanoreceptors)

  • Are specialized sensory receptors that respond to mechanical stimuli.
  • Types :
  • Merkel cells - in the epidermis (light touch & light)
  • Meissner's Corpuscles.

2. Peripheral Nerves :

  • Carry signals from mechanoreceptors to the (CNS.)

3. Spinal cord :

Enter the spinal cord & synapse with second -order neuron in the dorsal horn.

4. Ascending pathways :

The dorsal column - medial lemniscus pathway is particularly involved in transmitting fine touch , pressure ...

4. Brainstem

5. Thalamus

6. Primary Somatosensory cortex

  • Sensation reaching the cerebral cortex → conscious.
  • " terminate elsewhere → unconscious.

2 Types of sensory system :

1. General :

A. General somatic afferent.

  • Provides sensations from skin , joints , muscles , tendons
  • Pain - temp - light touch.
  • Proprioception and discriminative touch.

B. General visceral Afferent

senses info from internal organs , blood vessels & glands.

2. Special :

These systems are highly specialized for specific senses.

  • Sight
  • Sound
  • Smell
  • Taste
  • Balance.

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