Topic 3: senses - smell + taste

Question 1

What are the receptors for taste/smell?

Answer 1

• Chemoreceptors as smell + taste are chemical senses
• Chemoreceptors in taste buds + nasal passages

Question 2

Describe our chemical senses

Answer 2

• Sharpest at birth = innate
• Primitive sense

Question 3

Taste/Smell can trigger what?

Answer 3

• They can trigger memories + emotions
• Can alert us of danger
• Cases of PTSD/Depression

Question 4

Describe hypersomnia

Answer 4

• Sensitivity to smell
• Taste = smell connected by olfactory system = flavors more intense
• Causes = pregnancy + neurological conditions + autoimmune disease

Question 5

What is the smell humans are sensitive to?

Answer 5

• Petrichor = rain on dry soil
• Due to microscopic bacteria in soil = produce geosmin

Question 6

Describe the process of smelling

Answer 6

• Odorant must be volatile/gaseous = absorbed by nostrils
• Deeper sniff = more molecule absorbed = stronger smell
• Majority filtered out before reaching nasal cavity by hairs
• Molecules reach back of nose = olfactory epithelium
• Molecules dissolve in mucus coating of epithelium
• Molecules bind to receptors = threshold = activated neurons = firing action potential
• AP travel up axons -> ethmoid bone -> olfactory bulb -> brain

Question 7

Describe the olfactory epithelium

Answer 7

• Main organ of olfactory system = on the roof of nasal cavity
• Small yellow patch of tissue
• Contains millions of sensory neurons
• Neurons = bowling pin shaped = surrounded by insulating columnar supporting cells

Question 8

Describe the olfactory neurons

Answer 8

• Receptors for specific smell
• Odorant composition = odorant made of multiple chemicals
• Glomerulus = axons from smell specific neuron converge in glomerulus = tangled fibers