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Canada (161,803)
HLTC22H3 (102)
Anna Walsh (49)

HLTB01 Ch7 notes

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Health Studies
Anna Walsh

Chapter 7Aging and the regulatory SystemTextbook notesOrgans must recognize changes in both external and internal environment and be able to communicate with each other to maintain homeostasis in order to function properlySensory SystemComposed of five senses touch smell taste hearing and visionAllows the nervous system to gain information about the external environment Touch o Skin is the sense organ for touch o Touch receptors Meissners Corpuscles pressure receptors pacinian corpuscles o These receptors decrease both in number and sensitivity resulting in degradation of sense of touch and decreased ability to locate detect and identify objects Smell o Modest changes in smell occur with age only 10 decline oDecrease in number of sensory neurons in nasal lining and olfactory pathways of braino Smoking degrades it although some function may return when quit smoking o Olfactory bulb close to hippocampus first indicator of incipient alzheimers disease is a decrease in sense of smello Ability to smell food important to detect food gone bad causes food borne illnessesTaste o Taste buds on tongue sense salt sweet sour bitter fat and umami composed of glutamate monosodium glutamate o Gradual lose in taste may due to smoking periodontal disease illness or use of medications sudden loss may be indicative of brain tumour o Can lead to anorexia Hearing o Age related changes affect hearing and balance o Middle eara 3 ossicles little bones pass vibrations to the oval window b oval window a flexible membrane that is the beginning of the inner ear o Inner ear fluid puts pressure on the cochlea an organ that looks like a snail shell which is lined with basilar membrane which bristles with rows of thousand of neurons that make up organ of corti o These hair cells contact nerve fibers that transmit acoustic signals to the CNS o Vestibule allows organisms to sense gravity and head rotation consists of two small gelatine filled sacks that have small mineral particles and hairlike sensors o Ear wax lubricant that thickens with age and can build up decreasing sensitivity of sound ear drum can become stiffer the ossicles a bith arthritic this does not tend to affect hearingo Organ of corti affected by atheroscelorotic changes in the capillaries that provide nutrients to it by wear and tear and by ototoxic medication those that are toxic to the delicate mechanisms in the ear o Structures in ear that sense gravity and head position can degrade over time leading to dizziness and fallso Presbycusishearing loss most common men lose 80 of hearing capacity by 90 women lose 30 o Shorter hair cells respond to high frequencies are located at the beginning of cochleaand receive most wear and tear o Risk factors ototoxic drug use and occupations with high noice exposure Protective exercise positive effects on blood flow o African American men have less hearing loss and genetics play a role in accelerating and decelerating the loss of hearingo Linear increase in problem in physical health and mental health and social functioning with each decrement in hearing ability loss has profound effect on older adults quality of lifeo Tinnitusringing in the ears with no discernable cause common with age sources ear infections high blood pressure diabetes turmors atheroscelorsis malnutrition medications and toxic chemicalsthis is simply annoyance that can be masked by soft music but if severe can interfere with sleepVision o light passes through cornea a transparent structure that protects the eye o by contracting and dilating muscles in the iris regulate the amount of light that enters the eye o retina contains photoreceptors rods and cones o lensfocuses on the image on the retina adjusting for the distance of the object o photoreceptors translate light energy into action potentials in the optic nerve cones responsible for color vision rods only transmit information in black and white more sensitive to light o cone are numerous in macula which is center of gaze in direct line from cornea rods are typically found in the more peripheral regions of the retina o whole structure is supported by gel like substances called humours in the chambers in the eye
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