Chapter 7 Book Notes

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Health Studies
Ingrid L.Stefanovic

Health, Illness, and Optimal Aging- Biological and Psychological Perspectives Chapter 7: Aging of the Regulatory Systems - In order for the organs to function properly, they must recognize changes in both the external and internal environment and be able to communicate with each other to maintain homeostasis, avert dangers, and manage growth. - The regulatory systems that manage this communication are the sensory, nervous, endocrine, and immune systems. - Disruption in the communication among these systems plays a major role in the development of disease and in the aging process itself. - Less is known about how to maintain optimal health in these systems. SENSORY SYSTEMS - The sensory system is composed of five senses: touch, smell, taste, hearing and vision. - Sensory organs allow the nervous system to gain information about the external environment. - In the interest of brevity, we focus primarily on changes in the senses due to aging and disease rather than describing the anatomy and physiology of these highly complex organs in depth. FIVE SENSES and DISEASE RELATED CHANGES Touch - Sense organ for touch - Changes to touch receptors (Meissners corpuscles) and pressure receptors (Pacinian corpuscles) - With age- these receptors decrease with number and sensitivity, degradation of the sense touch, decreased ability to detect, locate, or identify objects Smell - Loss of sense of smell decreases by 10% - Decreases in numbers of sensory neurons in the nasal lining, and in the olfactory pathways to the brain - Food-borne illnesses are a risk for older adults who have lost their sense of smell, and they cant smell rotten eggs, milk or meat, as well as detecting leaking gases or bad body odours Taste - Test buds on the tongue can sense salt, sweet, sour, bitter, fat, and umami [glutamate form of monosodium glutamate] Health, Illness, and Optimal Aging- Biological and Psychological Perspectives - Gradual loss in taste, maybe due to smoking, periodontal diseases, or medication - Serious consequences leads to anorexia Hearing - Middle ear contains three ossicles (little bones) that pass vibrations to the oval window - Fluid in inner ear puts pressure on the cochlea - Vestibule, allows organisms to sense gravity and head rotation o Contains two small, geletin-filled sacks, with small mineral particles and hairlike sensors o These minerals press down on the sensors, transmitting info to the brain on position of the head-whether upright, down or tilted Cells in the ear canal develop earwax, decreasing sensitivity to sound Drugs, antibiotics, pain relievers, diuretics, and cancer drugs are toxic to the ear and its Corti Structure of the inner ear senses gravity & head position can also degrade with time, leading to dizziness, and falls Presbycusis- loss of hearing, most common hearing problem [men-90% and women -30% by 90] Hearing leads to older people becoming less attached to their environment, not being able to participate in conversations, hear others, listen to music or enjoy listening to nature Tinnitus, ringing in the ears with no discernible cause [ear infections, high blood pressure, diabetes, tumors, atherosclerosis, malnutrition, medications, and toxin chemicals Vision - Cornea- through which light passes [transparent structure that protects the eye] - Iris [contracts & dilates]- regulates the amount of light enters the eyes - Retina- contains photoreceptors [rods & cones] lens focuses on the image on the retina adjusting for the distance of the object - Cones- colour vision - Rods- black and white - Humor- gel-like substance protects the eye against shock
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