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.