The document discusses the senses of smell, taste, and touch. It explains that smell occurs when organic molecules bind to receptors in the nose. Taste happens when molecules bind to receptors on the tongue in different regions based on the type of taste. The tongue can detect sweet, sour, salty, and bitter. Touch is the detection of pressure and temperature changes by different receptor types in the skin like Meissner's receptors and Pacinian receptors.

1. ANATOMY
Unit 1 NOTES:
Taste, Touch,
Smell

2. (1) Smell
• Smell is the binding of organic molecules to
receptors deep within the nose.
• Your nose is lined with olfactory
receptors…
– Air flows in carrying organic molecules
– Organic molecules dissolve in mucus lining
– Organic molecules bind to receptors
– Impulse sent through Olfactory Nerve

4. (2) Taste
• Taste is the binding of molecules to
receptors on tongue.
• Tongue is covered in papillae projections,
covered in “taste buds” or gustatory cells:
– Organic Molecules dissolve in saliva
– Molecules bind to gustatory cells
– Impulse sent to brain

6. (3) Taste Regions on Tongue
• Sweet:
– Receptors bind with monosaccharides and amino acids
– Location: Front & Center of Tongue
• Sour:
– Receptors bind with hydrogen ions (acid)
– Location: Sides of Tongue
• Salty:
– Receptors bind with metal ions
– Location: Front & Sides of Tongue
• Bitter:
– Receptors bind with alkaloids (typically nitrogenous)
– Location: Very Back of Tongue

8. (4) Touch
• Touch = Pressure against skin
• Skin contains pressure + temperature receptors…
– Meissner’s Receptors = Super Sensitive
• Palms, Feet, Lips, Eyelids
• Minimal pressure needed
– Paccinian Receptors = Deep Receptors
• Pressure + Vibration
– Nociceptor Receptors= Sense Pain
• Most Abundant on body
– Thermoreceptors = Sense Temperature
• Individual neurons for hot and for cold
• Increase nerve impulses with changes in temperature