Describe General Senses

Sensation

• stimulus consciously aware of

• for consciousness, signal to cerebral cortex (fraction of stimuli)

Modality

• type of stimulus

  • brain interprets optic nerve signals to occipital lobe as visual, cochlear to temporal as auditory

Adaptation

• decreased sensitivity to continuous stimulus

  • intensity of stim determined by frequency

  • strong = more neurons to fire and sensitive neurons fire more frequently

• receptor adaptation = stimulus duration

Receptor Classification

• General sense: simple structures throughout body

• Somatic sensory: tactile receptors skin and mucous membranes; proprioceptors joints, muscle and tendons

• Visceral sensory: walls internal organs, monitor stretch, chemical environment, temp, pain

• Special sense: olfaction, gustation, vision, audition, equilibrium

• Exteroceptors: stimuli external environments

• Interceptors: internal organs

• Proprioceptors: body and limb movement, somatosensory receptors of muscles, tendons and joints

• Categorized by MODALITY OF STIMULUS (stimulating agents

Modality of Stimulus

• Chemoreceptors: chemicals dissolved in fluid, receptors for external or internal environments

• Thermoreceptors: temp

• Photoreceptors: light intensity, color, movement

• Mechanoreceptors: distortion of cell membrane (touch, pressure, vibration, stretch)

• Nociceptors: pain

Proprioceptors

• general sensory receptors (6th sense) in muscles, tendons and joints

• relay info body position and movement, tonic receptors

• 3 types

  • Muscle spindle: stretch in skm

  • Golgi tendon organ: stretch in tendon

  • Joint kinesthetic receptor: stretch in articular capsule