Transcript Slide 8.39a
Special Senses: Taste and Smell Ch. 8c Chemical Senses – Taste and Smell Both senses use chemoreceptors Stimulated by chemicals in solution Taste has four types of receptors Smell can differentiate a large range of chemicals Both senses complement each other and respond to many of the same stimuli Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 8.34 Olfaction – The Sense of Smell Olfactory receptors are in the roof of the nasal cavity Neurons with long cilia Chemicals must be dissolved in mucus for detection Impulses are transmitted via the olfactory nerve Interpretation of smells is made in the cortex Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 8.35 Olfactory Epithelium Figure 8.17 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 8.36 Quick Quiz 1 of 2 • What are the receptors for smell called? • What nerve carries smell impulses to the brain? The Sense of Taste Taste buds house the receptor organs Location of taste buds Most are on the tongue Soft palate Cheeks Figure 8.18a, b Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 8.37 The Tongue and Taste The tongue is covered with projections called papillae Filiform papillae – sharp with no taste buds Fungifiorm papillae – rounded with taste buds Circumvallate papillae – large papillae with taste buds Taste buds are found on the sides of papillae Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 8.38 Structure of Taste Buds Gustatory cells are the receptors Have gustatory hairs (long microvilli) Hairs are stimulated by chemicals dissolved in saliva Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 8.39a Structure of Taste Buds Impulses are carried to the gustatory complex by several cranial nerves because taste buds are found in different areas Facial nerve Glossopharyngeal nerve Vagus nerve Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 8.39b Anatomy of Taste Buds Figure 8.18 Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 8.40 Taste Sensations Sweet receptors: tip of tongue Sugars Saccharine Some amino acids Sour receptors: back sides of tongue Acids Bitter receptors: Back of tongue Alkaloids Salty receptors: Frong sides of tongue Metal ions Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings Slide 8.41 Quick Quiz 2 of 2 • What are the receptor cells called that carry taste sensations to the brain? • On what part of your tongue to you sense sweet?