CJ

Senses_final

Senses Overview

  • Instructor: Prof. Maribel O. Losito, RMT, MPH

Learning Outcomes

  • Identify various types of general sensory receptors.

  • List stimuli activating general sensory receptors.

  • Describe the five special senses: olfaction, taste, sight, hearing, and balance/equilibrium.

Stimulus Detection Process

  1. Detection: Sensory receptors detect stimuli from the environment.

  2. Signal Transmission: Sensory neurons conduct nerve impulses to the spinal cord and brain.

  3. Interpretation: Brain interprets information from sensory receptors.

  4. Perception: The interpretation results in perception of the stimulus.

Definitions

  • Stimuli: Anything inducing a response in an organism.

  • Senses: Ways the brain receives information about the environment.

  • Sensation: Process initiated by stimulating sensory receptors.

  • Perception: Conscious awareness of stimuli.

Types of Senses

General Senses

  • Receptors distributed throughout the body.

  • Includes somatic and visceral senses.

Special Senses

  • More specific and localized (smell, taste, vision, hearing, balance).

Types of Sensory Receptors

  • Mechanoreceptors: Respond to mechanical stimuli.

  • Photoreceptors: Respond to light.

  • Chemoreceptors: Respond to chemicals.

  • Thermoreceptors: Respond to temperature changes.

  • Nociceptors: Respond to pain stimuli.

Summary of General Senses

  • Touch: Pressure, proprioception, temperature, and pain across the body.

  • Special Senses: Smell (olfaction), balance, taste, hearing, vision.

Proprioception

  • Sense of body awareness through proprioceptors in muscles and tendons.

  • Allows movement without conscious awareness.

Special Senses

Olfaction (Smell)

  • Airborne odorants bind to receptors on olfactory neurons, initiating action potentials to the olfactory cortex.

Taste

  • Taste buds with taste cells detect dissolved substances, recognizing five basic tastes: sour, salty, bitter, sweet, and umami.

Sight

  • Visual system includes eyes and accessory structures, with input about light, movement, and color.

Hearing and Balance

Anatomy of the Ear

  • External Ear: Collects sound waves.

  • Middle Ear: Transmits vibrations from the tympanic membrane via auditory ossicles.

  • Inner Ear: Contains cochlea for hearing and vestibule for balance.

Age-Related Changes in Senses

  • Decrease in sensory function with age, affecting balance, taste, and smell.

  • Common age-related conditions: presbyopia (vision), presbycusis (hearing), cataracts, and diabetic retinopathy.

Vision Disorders

  • Myopia: Nearsightedness.

  • Hyperopia: Farsightedness.

  • Astigmatism: Irregular lens curvature.

  • Cataracts: Clouding of the lens.

  • Glaucoma: Increased internal eye pressure.

  • Night Blindness: Difficulty seeing in dim light.

  • Color Blindness: Difficulty distinguishing colors.

Hearing Disorders

  • Tinnitus: Phantom sound sensation.

  • Meniere’s Disease: Vertigo and hearing loss related to fluid abnormalities in the inner ear.