Quote of the Week: ”I believe in an open mind, but not so open that your brains fall out.” -Arthur Hays Sulzberger Thursday February 11, 2016 Do Now: socrative.com 329anatomy Homework:  (Z): Parts of a Neuron  (Z): Organization of the Nervous System  (Z): Sympathetic vs Parasympathetic  (Z): Neuroglia  (Z): Spinal Cord  (Z): Protection of the CNS  (Z): Brain Anatomy  (Z): Brain Mapping  (Z): Special Senses: Smell  Brain Dissection Lab due 2/12  Nervous System Test 2/18 MS. GALLAGHER’S ANATOMY & PHYSIOLOGY Agenda: Complete & Review “Do Now” Finish Brain Dissection Finish Post-Lab Individually Standards: HS-LS1-2

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 © 2015 Pearson Education, Inc.

Olfaction—The Sense of Smell Olfactory receptors are in roof of nasal cavity – Olfactory receptors cells (neurons) with long cilia known as olfactory hairs detect chemicals – Chemicals must be dissolved in mucus for detection by chemoreceptors called olfactory receptors Impulses are transmitted via the olfactory filaments to the olfactory nerve Interpretation of smells is made in the cortex © 2015 Pearson Education, Inc.

Figure 8.18 Location and cellular makeup of the olfactory epithelium. Olfactory bulb Olfactory tract Cribriform plate of ethmoid bone Olfactory mucosa Mucus layer Olfactory filaments of the olfactory nerve Olfactory hairs (cilia) Olfactory receptor cell Supporting cell Route of inhaled air containing odor molecules (a) (b)

Taste Buds and the Sense of Taste Taste buds house the receptor organs Locations of taste buds – Most are on the tongue – Soft palate – Cheeks © 2015 Pearson Education, Inc.

Taste Buds and the Sense of Taste The tongue is covered with projections called papillae – Filiform papillae—sharp with no taste buds – Fungiform papillae—rounded with taste buds – Circumvallate papillae—large papillae with taste buds Taste buds are found on the sides of papillae © 2015 Pearson Education, Inc.

Figure 8.19a Location and structure of taste buds. Epiglottis Palatine tonsil Lingual tonsil (a) Fungiform papillae

Figure 8.19b Location and structure of taste buds. Vallate papilla Taste buds (b)

Structure of Taste Buds Gustatory cells are the receptors – Possess gustatory hairs (long microvilli) – Hairs are stimulated by chemicals dissolved in saliva © 2015 Pearson Education, Inc.

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 (cranial nerve VII) – Glossopharyngeal nerve (cranial nerve IX) – Vagus nerve (cranial nerve X) Taste buds are replaced frequently by basal cells © 2015 Pearson Education, Inc.

Taste Sensations Sweet receptors respond to sugars, saccharine, some amino acids Sour receptors respond to H  ions or acids Bitter receptors respond to alkaloids Salty receptors respond to metal ions Umami receptors respond to the amino acid glutamate or the beefy taste of meat © 2015 Pearson Education, Inc.