1. ANATOMY
Unit 2 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