Special Senses & Endocrine System Overview for BIOL 2401: An In-Depth Study

1. BIOL 2401 Fundamentals of Anatomy and Physiology Mrs. Willie Grant wgrant4@alamo.edu (210)486-2780

4. An Introduction to the Special Senses Learning Outcomes 17-1 Describe the sensory organs of smell, trace the olfactory pathways to their destinations in the brain, and explain the physiological basis of olfactory discrimination. 17-2 Describe the sensory organs of taste, trace the gustatory pathways to their destinations in the brain, and explain the physiological basis of gustatory discrimination. 17-3 Identify the internal and accessory structures of the eye, and explain the functions of each. 17-4 Explain color and depth perception, describe how light stimulates the production of nerve impulses, and trace the visual pathways to their destinations in the brain. 17-5 Describe the structures of the external, middle, and internal ear, explain their roles in equilibrium and hearing, and trace the pathways for equilibrium and hearing to their destinations in the brain.

5. An Introduction to the Endocrine System Learning Outcomes 18-1 Explain the importance of intercellular communication, describe the mechanisms involved, and compare the modes of intercellular communication that occur in the endocrine and nervous systems. 18-2 Compare the cellular components of the endocrine system with those of other systems, contrast the major structural classes of hormones, and explain the general mechanisms of hormonal action on target organs. 18-3 Describe the location, hormones, and functions of the pituitary gland, and discuss the effects of abnormal pituitary hormone production. 18-4 Describe the location, hormones, and functions of the thyroid gland, and discuss the effects of abnormal thyroid hormone production. 18-5 Describe the location, hormone, and functions of the parathyroid glands, and discuss the effects of abnormal parathyroid hormone production. 18-6 Describe the location, structure, hormones, and general functions of the adrenal glands, and discuss the effects of abnormal adrenal hormone production. 18-7 Describe the location of the pineal gland, and discuss the functions of the hormone it produces. 18-8 Describe the location, structure, hormones, and functions of the pancreas, and discuss the effects of abnormal pancreatic hormone production.

6. An Introduction to the Special Senses Five Special Senses Olfaction Gustation Vision Equilibrium Hearing

7. 17-2 Taste (Gustation) Taste Receptors (Gustatory Receptors) Are distributed on tongue and portions of pharynx and larynx; clustered into taste buds Taste Buds Associated with epithelial projections (lingual papillae) on superior surface of tongue Three Types of Lingual Papillae Filiform papillae Provide friction Do not contain taste buds Fungiform papillae Contain five taste buds each Circumvallate papillae Contain 100 taste buds each Monitored by cranial nerves that synapse within solitary nucleus of medulla oblongata Then on to thalamus and primary sensory cortex

8. Beef, chicken broth, Parmesan cheese 1 What is umami?

9. 17-3 Accessory Structures of the Eye Vision Accessory Structures of the Eye Provide protection, lubrication, and support Include: The palpebrae (eyelids) The superficial epithelium of eye The lacrimal apparatus Eyelids (Palpebrae) Continuation of skin Blinking keeps surface of eye lubricated, free of dust and debris Eyelashes Robust hairs that prevent foreign matter from reaching surface of eye

10. 2 What is lacrimal fluid?

12. 17-3 The Eye Three Layers of the Eye Outer fibrous layer Intermediate vascular layer Deep inner layer Eyeball Is hollow Is divided into two cavities Largeposterior cavity Smalleranterior cavity 3 What are the components of the fibrous tunic and vascular tunic?

13. Light Refraction Bending of light by cornea and lens Focal point Specific point of intersection on retina Focal distance is determined by two factors (a and b).

14. 17-3 The Eye Light Refraction of Lens Accommodation—the shape of the lens changes to focus image on retina Astigmatism Condition where light passing through cornea and lens is not refracted properly and the visual image is distorted.

15. Light Refraction of Lens • Image reversal • Visual acuity • Clarity of vision • “Normal” rating is 20/20 4 What is presbyopia?

16. Figure 17-20 The Visual Pathways Visual Field Combined Left side Right side Left eye Right eye The Visual Pathways. The crossover of some nerve fibers occurs at the optic chiasm. As a result, each hemisphere receives visual information from the medial half of the field of vision of the eye on that side, and from the lateral half of the field of vision of the eye on the opposite side. Visual association areas integrate this information to develop a composite picture of the entire field of vision. only Binocular vision only The Visual Pathway Retina Photoreceptorsin retina Optic disc Optic nerve(N II) Optic chiasm Optic tract Suprachiasmaticnucleus Diencephalonandbrain stem Lateralgeniculatenucleus Projection fibers(optic radiation) Visual cortexof cerebralhemispheres Superiorcolliculus Left cerebralhemisphere Right cerebralhemisphere

17. 17-5 The Ear Hearing The External Ear Auricle Surrounds entrance to external acoustic meatus Protects opening of canal Provides directional sensitivity External acoustic meatus Ends at tympanic membrane (eardrum) Tympanic membrane Is a thin, semitransparent sheet Separates external ear from middle ear Ceruminous glands Integumentary glands along external acoustic meatus Secrete waxy material (cerumen) Keeps foreign objects out of tympanic membrane Slows growth of microorganisms in external acoustic meatus

18. Figure 17-21 The Anatomy of the Ear Middle Ear Internal Ear External Ear Elastic cartilages Auditory ossicles Ovalwindow Semicircular canals Petrous part oftemporal bone Auricle Facial nerve (N VII) Vestibulocochlearnerve (N VIII) Bony labyrinthof internal ear Cochlea Tympaniccavity Auditory tube Tonasopharynx Tympanicmembrane Vestibule External acousticmeatus Roundwindow 5 To which structure of the external ear does the malleus of the middle ear attach?

20. 6 What are the names of the two sacs that lie in the membranous labyrinth of the vestibule?

22. Figure 17-26 Pathways for Equilibrium Sensations To superior colliculus andrelay to cerebral cortex Red nucleus N III Vestibularganglion N IV Vestibularbranch Semicircularcanals Vestibular nucleus N VI Tocerebellum Vestibule N XI Cochlearbranch Vestibulocochlear nerve(N VIII) Vestibulospinaltracts 7 What is dynamic equilibrium?

24. Clinical Case—A Chance to See What does Makena’s initial eye test finding of 20/200 mean? If Makena’s vision is corrected to a state of emmetropia, what does this mean?

26. An Introduction to the Endocrine System The Endocrine System Regulates long-term processes Growth Development Reproduction Uses chemical messengers to relay information and instructions between cells 8 What is the basic difference between endocrine glands and exocrine glands?

27. 18-1 Homeostasis and Intercellular Communication Direct Communication Exchange of ions and molecules between adjacent cells across gap junctions Occurs between two cells of same type and is highly specialized and rare Paracrine Communication Uses chemical signals to transfer information from cell to cell within single tissue Most common form of intercellular communication Target Cells Are specific cells that possess receptors needed to bind and “read” hormonal messages Hormones Stimulate synthesis of enzymes or structural proteins Increase or decrease rate of synthesis Turn existing enzyme or membrane channel “on” or “off” Synaptic Communication Ideal for crisis management Occurs across synaptic clefts Chemical message is “neurotransmitter” Limited to a very specific area 9 What is the difference between an autocrine and a paracrine hormone?

29. 10 Is the pancreas an endocrine or an exocrine gland?

33. Figure 18-20 The General Adaptation Syndrome ALARM Alarm Phase (“Fight or Flight”) During the alarm phase, an immediate response to the stress occurs. The sympathetic division of the autonomic nervous system directs this response. In the alarm phase, (1) energy reserves are mobilized, mainly in the form of glucose, and (2) the body prepares to deal with the stress-causing factor by “fight or flight” responses. Epinephrine is the dominant hormone of the alarm phase. Its secretion is part of a generalized sympathetic activation. Immediate Short-Term Responses to Crises Brain General sympathetic activation • Increased mental alertness • Increased energy use by all cells • Mobilization of glycogen and lipid reserves • Changes in circulation • Reduction in digestive activity and urine production • Increased sweat gland secretion • Increased heart rate and respiratory rate Adrenal medulla Sympathetic stimulation Epinephrine, norepinephrine RESISTANCE Resistance Phase If a stress lasts longer than a few hours, the individual enters the resistance phase of the GAS. Glucocorticoids are the dominant hormones of the resistance phase. Epine- phrine, GH, and thyroid hormones are also involved. Energy demands in the resistance phase remain higher than normal, due to the combined effects of these hormones. Neural tissue has a high demand for energy, and requires a reliable supply of glucose. If blood glucose levels fall too far, neural function deteriorates. Glycogen reserves can meet neural demand during the alarm phase, but become depleted after several hours. Hormones of the resistance phase mobilize metabolic reserves and shift tissue metabolism away from glucose, thus increasing its availability to neural tissue. Long-Term Metabolic Adjustments Growth hormone Pancreas • Mobilization of remaining energy reserves: Lipids are released by adipose tissue; amino acids are released by skeletal muscle • Conservation of glucose: Peripheral tissues (except neural) break down lipids to obtain energy • Elevation of blood glucose concentrations: Liver synthesizes glucose from other carbohydrates, amino acids, and lipids • Conservation of salts and water, loss of K+ and H+ Glucagon Sympathetic stimulation ACTH Adrenal cortex Glucocorticoids Kidney Mineralocorticoids (with ADH) Renin-angiotensin system EXHAUSTION Exhaustion Phase The body’s lipid reserves are sufficient to maintain the resistance phase for weeks or even months. But when the resistance phase ends, homeostatic regulation breaks down and the exhaustion phase begins. Unless corrective actions are taken almost immediately, the failure of one or more organ systems will prove fatal. The production of aldosterone throughout the resistance phase results in a conservation of Na+ at the expense of K+. As the body’s K+ content declines, a variety of cells begin to malfunction. The underlying problem of the exhaustion phase is the body’s inability to sustain the endocrine and metabolic adjustments of the resistance phase. Collapse of Vital Systems • Exhaustion of lipid reserves • Cumulative structural or functional damage to vital organs • Inability to produce glucocorticoids • Failure of electrolyte balance

35. Clinical Case—Stones, Bones, and Groans In addition to mobilizing calcium from bone, how else does PTH increase blood calcium levels? What hormone counteracts PTH and decreases blood Ca2+ levels?