Sense Organs: The Human Eye

Sense Organs

Eye

• Responsible for detecting light and converting it into electrical signals that are transmitted to the brain
• Structure:
  • Cornea: transparent outer layer
  • Iris: colored part that controls amount of light entering the eye
  • Lens: focuses light onto the retina
  • Retina: contains photoreceptors (rods and cones) that convert light into electrical signals
• Functions:
  • Detects light, color, and movement
  • Focuses on objects at varying distances
  • Regulates amount of light entering the eye through pupil constriction/dilation

Ear

• Responsible for detecting sound waves and balance
• Structure:
  • Outer ear: collects sound waves
  • Middle ear: amplifies sound waves through ossicles (malleus, incus, stapes)
  • Inner ear: contains cochlea (sound detection) and vestibular apparatus (balance)
• Functions:
  • Detects sound waves and converts them into electrical signals
  • Maintains balance and equilibrium through vestibular apparatus

Nose

• Responsible for detecting odor molecules
• Structure:
  • Nostrils: entrance for air and odor molecules
  • Olfactory epithelium: contains olfactory receptors that bind to odor molecules
  • Olfactory bulb: processes and interprets odor information
• Functions:
  • Detects odor molecules and identifies specific smells
  • Plays role in taste and flavor perception

Tongue

• Responsible for detecting taste molecules
• Structure:
  • Taste buds: contain taste receptors that bind to taste molecules
  • Papillae: small bumps on the tongue's surface that house taste buds
• Functions:
  • Detects sweet, sour, salty, bitter, and umami tastes
  • Plays role in flavor perception and appreciation

Skin

• Responsible for detecting touch, pressure, temperature, and pain
• Structure:
  • Epidermis: outermost layer
  • Dermis: layer beneath epidermis containing sensory receptors
  • Hypodermis: layer beneath dermis
• Functions:
  • Detects touch, pressure, temperature, and pain through mechanoreceptors, thermoreceptors, and nociceptors
  • Regulates body temperature through sweat glands and blood vessels

Sense Organs

Eye

• Detects light and converts it into electrical signals transmitted to the brain
• Composed of cornea (transparent outer layer), iris (colored part controlling light entry), lens (focuses light onto retina), and retina (contains photoreceptors converting light into electrical signals)
• Functions include detecting light, color, and movement, focusing on objects at varying distances, and regulating light entry through pupil constriction/dilation

Ear

• Detects sound waves and balance
• Composed of outer ear (collects sound waves), middle ear (amplifies sound waves through ossicles), and inner ear (contains cochlea for sound detection and vestibular apparatus for balance)
• Functions include detecting sound waves, converting them into electrical signals, and maintaining balance and equilibrium through vestibular apparatus

Nose

• Detects odor molecules
• Composed of nostrils (entrance for air and odor molecules), olfactory epithelium (contains olfactory receptors binding to odor molecules), and olfactory bulb (processes and interprets odor information)
• Functions include detecting odor molecules and identifying specific smells, and playing a role in taste and flavor perception

Tongue

• Detects taste molecules
• Composed of taste buds (contain taste receptors binding to taste molecules) and papillae (small bumps housing taste buds)
• Functions include detecting sweet, sour, salty, bitter, and umami tastes, and playing a role in flavor perception and appreciation

Skin

• Detects touch, pressure, temperature, and pain
• Composed of epidermis (outermost layer), dermis (layer beneath epidermis containing sensory receptors), and hypodermis (layer beneath dermis)
• Functions include detecting touch, pressure, temperature, and pain through mechanoreceptors, thermoreceptors, and nociceptors, and regulating body temperature through sweat glands and blood vessels

Sense Organs

Skin

• Covers the entire body, functioning as the largest sense organ
• Detects sensations such as pressure, temperature, pain, and touch
• Regulates body temperature and protects the body from external damage
• Has receptors that detect specific sensations:
  • Meissner's corpuscles for light touch
  • Pacinian corpuscles for pressure and vibration
  • Free nerve endings for pain and temperature

Eye

Structure

• Composed of cornea (transparent outer layer), iris (regulates light entry), lens (focuses light), and retina (light-sensitive cells)

Function

• Detects light and color
• Focuses light to form an image on the retina
• Transmits visual information to the brain

Ear

Structure

• Divided into outer ear (collects sound waves), middle ear (amplifies sound waves), and inner ear (converts sound waves to nerve signals)

Function

• Detects sound waves and vibrations
• Maintains balance and equilibrium
• Converts sound waves to nerve signals for the brain to interpret

Nose

Structure

• Composed of olfactory receptors (detect odor molecules) and nasal cavity

Function

• Detects odor molecules in the air
• Transmits odor information to the brain
• Aids in taste perception

Tongue

Structure

• Composed of taste buds (contain taste receptors) and papillae (small bumps)

Function

• Detects chemical properties of food (sweet, sour, salty, bitter, umami)
• Aids in the sensation of flavor
• Helps with food identification and selection