Textbook Notes (363,062)
Canada (158,169)
HSM 330 (12)
Chapter 7

HSM330 Chapter 7 notes

18 Pages
Unlock Document

Ryerson University
Health Services Management
HSM 330
Daolun Chen

Chapter 7(Aging and the regulatory System) – Textbook notes - Organs must recognize changes in both external and internal environment and be able to communicate with each other to maintain homeostasis in order to function properly Sensory System - Composed of five senses: touch, smell, taste, hearing, and vision - Allows the nervous system to gain information about the external environment Touch o Skin is the sense organ for touch o Touch receptors= Meissner’s 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 o Decrease in number of sensory neurons in nasal lining and olfactory pathways of brain o Smoking degrades it although some function may return when quit smoking o Olfactory bulb close to hippocampus, first indicator of incipient alzheimer’s disease is a decrease in sense of smell o Ability to smell food important to detect food gone bad, causes food borne illnesses Taste 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 ear  a) 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 hearing o 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 falls o Presbycusis = hearing 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 cochlea and 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 hearing o 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 life o Tinnitus : ringing in the ears with no discernable cause, common with age; sources: ear infections, high blood pressure, diabetes, turmors, atheroscelorsis, malnutrition, medications and toxic chemicals ; this is simply annoyance that can be masked by soft music, but if severe can interfere with sleep Vision 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 lens focuses 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 o Aqueous (water) humor not only provides support but also transports nutrients and wastes, wheres the more gel- like vitrerous humor protects the eye against shock o Conjunctiva : a clear mucus membranes inside eyelids, provide protection o Cornea, lens and vitreous humor all diminish in transparency, reducing the amount of light entering the eye and also scattering the light that does come in, making the eye more sensitive to glare o Yellowing of the lens also decreases its transparency and makes it difficult to differentiate blues, greens and violets o Lens loses elasticity with age, making it more difficult to focus on near objects called presbyopia which is the most common age related visual problem; curvature of the cornea becomes more irregular, resulting in astigmatisms that distort vision by doubling the edges of objects o Muscles in iris decrease in number and strength with age, reducing the ability of the pupil to enlarge, process begins at about age 20 and steadily reduces the amount of light available to the eye ; Older adults more vulnerable to glare and reduces their ability to see at night o lacrimal (tear) gland and conjunctiva produce less of their protective fluids which can result in inflammation and irritation, the rate at which aqueous humor is generated also declines, and there might not be enough to properly maintain the shape of the cornea o vitreous humor also decrease in size and becomes more liquid, as the VH moves about it can create tension on the retina, causing flashes; to much tension can cause the retina to detach causing blindness o cones and rods lose sensitivity progressively from adolescence and through the remainder of their life o rods in the central retina are vulnerable to aging, rods in older person retina may become irregular further decreasing the ability to see in dim light. Optic nerve fibers are also lost, decreasing the quality of vision o make diving problematic for old people especially in light, would be blinded and slow down by glare of headlights o most common disease of eye in late life cataracts, macular degeneration, glaucoma and diabetic retinopathy Cataracts  cloudiness or opacity of the lnes  frequently in later years, although can occur at any age  painless, can interfere with vision, particularly at night or in bright light  risk factors: exposure to UVB light, environmental pollutants, topical or internal steroids, diabetes, smoking, dehydration, eye trauma, low levels of antioxidants such as VIT. A C, E  easily treatable by surgery which involves removal of lens and replacement by artificial one  leading cause of blindness in developing countries Glaucoma  leading cause of blindness in adults over age of 50  caused by an increasing buildup of aqueous humor in the eye, resulting in an increase in intraocular pressure and damage to the retina and optic nerve  present for many years without symptoms  narrow angle/ primary angle- closure, occurs in 10% very rapid increase in pressure that can result in blindness quickly  risk: African American descent, or with a family history of g., high blood pressure and diabetes Age-related macular Degenderation (AMD)  40% of visual impairment in people over the age of 80 is the leading cause of severe vision loss in people over 60  Wet (exudative) or dry (atrophic)  Dry= gradual onset/ most common, wet= sudden resulting in precipitous visual decline/severe vision loss  Free radical damage the supply of nutrients to the retina and the macula of the eye degenerates, destroying central vision  High doses of antioxidants such as vit E are often use to slow its progression although no cure, surgery effective in halting damage to wet or exudative AMD, where eye is drained of v. Humor and lasers are use to repair the retina ** Best way to maintain sensory system is to avoid smoking tobacoo, which affects taste buds, risk factor for cataracts, and may accelerate hearing loss, due to its effects on cardiovascular system Nervous System - Primary regulator of body, monitors and provides communication between all systems and regulates homeostasis - Permits voluntary movement and underlies all cognitive processes, including sensation, attention, language, memory, emotions, and problem solving - CNS consists of brain and the spinal cord, PNS consists of sensory and motor neurons, ANS is responsible for all regulatory functions including monitoring and controlling blood pressure, digestion, respiration and temperature - Communication across synapses is primarily chemical and can be electrical, especially outside of the brain - NT which are small molecule, rapidly acting transmitters and neuropeptides which are larger, slowly acting transmitters and include hormones and enkephalins - Neuroglial cells provide support for neurons, synthesize the myelin sheath an insulating material around axons that speeds up the transmission of the nerve impulse - Myelinated axons are called white matter, nonmyelinaized areas such as nerve cell bodies are called grey matter and are important because they contain the synapses - Target cells produce neurotrophic factors such as nerve growth factor (NGF), and brain derived neurotrophic factor (BDNF) which protect neurons, regulate their growth and function and can contribute to CNS plasticity by promoting dendrification - CSF provides support for the brain - CSF is generated by Choroid plexuses in ventricular system is a series of spaces filled with CSF in the bottom and centre of the brain - Phylogenetically oldest part of the brain is the brain stem, which regulates heart rate and respiration , the reticular formation within the brain stem mediates basic alterness - Around brain stem is the cerebellum which controls balance, body position, and movement in space and may store certain typs of procedural memory related to movement such as riding a bike - Brain stem is the limbic system, which regulated many important functions such as homeostasis - Homeostasis regulated by pituitary gland and hypothalamus, memory consolidation (mediated by hippocampus) and emotions (mediated by amygdale and pituitary) - Limbic system is wrapped around the thalamus - Cerebrum is the largest part of the brain divided into two hempispheres connected by the corpus callosum, consists of white matter and is covered by the cortex which consists of gray matter - Increase surface area, the cortex is folded into ridges called gyri, spaces between gyri called sulci - Occipital lobe = visual info. , parietal lobe = somatosensory info, frontal lobe= voluntary motor behaviour, language production, and higher order cognitive and emotional processing; temporal lobes= process hearing, recognition of faces, and higher order visual processing and may be involved in emotional control - Do not believe in strict localization of function theory but rather posit that the brain functions as an integrated whole - Stimulus sets off temporal patterns of neural discharges throughout the brain, suggesting that the brain (and consciousness) functions more as a dispersed field, perhaps guied by constructs in quantum mechanics Age related Changes o Major loss of neurons with age o 10 to 15% decrease in brain matter with age o MRIs can image soft tissue as well o Loss of large neurons, which is compensated for by the greater relative efficiency of the remaining small neurons o Brain compensate for neuronal loss with extra dendritic branching to maintain neural pathway, and substantial number of neurons must be lost to affect functioning o Older neurons especially those which do not get sufficient blood flow (perfusion) may not process glucose as effectively as younger neurons o Damaged neurons do not produce glucose efficiently, more efficient neurons also use less glucose, older individual neurons may be using more glucose because of impairment or increase efficiency o Speed of action potentials decreases with age in PNS and CNS, due to poorer vascular perfusion of the cell body as well as damage to the myelin sheath o Decrease of acetylcholine, both presynaptic and postsynaptic domapine levels decrease, increase of norepinephrine in some areas of brain and decrease of serotonin o Orthostatic hypotension, dramtic decrease in BP when changing from a supin to a standing position, which can result in dizziness and falls o SNS maintain adequate levels of bloop pressure by stimulating cardiac activity and constricting blood vessels, however, the norepinephrine receptors may be less responsive to SNS stimulation(accounting for higher levels of blood norephinphrine) thus the heart and blood vessels do not respond rapidly enough to maintain BP o Appears to be decrease in number of motor neurons, as well as a decline in the speed of transmission from the neurons to the muscle cells o Blood Brain Barrier(BBB) interesting structure composed primarily of glial and other supporting cells that serve as a buffer between the nerve cells int he brain and the circulating blood, protecting the nerve cells from many harmful chemicals o BBB can become more porous permitting greater exposure to toxic chemicals as well as medications, drugs, or alcohol o Brain reserve capacity hypothesis suggest that the brain can absorb a fair amount of damage and still function relatively normally, given its redundant pathways Disease-related Processes o Cerebrovascular accidents (CVAs) or strokes are most common incidences of brain, increase of also Dementia, Parkinson’s Strokes  CVA’s result from same ischemic problems as do myocardial infarctions or heart attacks, which is why called brain attacks  Hypertension, arterioscelorosis, atheroscelorsis cause damage not only to the coronary arteries b ut also to other arteries, aarterioles and capillaries in the brain  Small temporary ischemic blockages are called transitory ischemic attacks or TIAs or ministrokes major risk factors for subsequent strokes  CVAs result form more permanent blockages in blood delivery system in the brain which can cause the veseel to be blocked or, less frequently to rupture  Aneurisms (weak ended areas of blood vessels) can also cause vessels to rupture and create serious damage  Language is profoundly impaired, Broca’s areas in frontal cortext have difficutly producing speech but comprehension skills such as reading and writing preserved; damage in Wernickes ares in the temporal lobe may talk a blue streak (which may be more or less intelligent) but be unable to comprehend language  Ischemia and haemorrhaging are not the only source of damage in strokes  Inflammation and cerebral edema(swelling) usually about 3 days after initial stroke, can result in further deterioration of brain functioning  Axons are capable of self repair, and increase dendritic branching may occur to restory neuronal pathways, NGF may assist in recovery of function processes in part by stimulating dendritic branching  Blockage, an anticoagulant( blood thinner) such as heparin is administered to lower blood pressure. A new treatment involves tissue plasminogen activator (TPA)which if administered within 3 hours of stroke can help dissolve clot  TPA can improve functioning by 30% but cannot be used for haemorrhages or if the patient has been on anticoagulants, if patient is haemorrhaging antihypertensives are used  Strokes may lead to dementia Dementia  Relatively rare among young-old people  Nearly 1/3 of people over the age of 85 suffer  Vascular dementia is caused by series of TIAs  Pick’s disease and Creuzfeldt-Jakob disease are particularly virulent dementias characterized by very rapid declines  Common form of dementia is Alzheimers Disease (AD)  An increase in neuritic plaques and neurofibrillary tangles. Neuritic plaques are composed of beta-amyloid protens and dead neurons; neurofibrillary tangles consist of tau protein fibers twisted into a helix and lippoteins called apoliprotein E (APOPE)  Hallmark of AD is a massive loss of neurons, especially cholingergic neurons. Brain atropheies and the ventricles become enlarged as do the sulci  Begins in the hippocampus and in the innermost regions of temporal lobes  Plaques and tangles infiltrate subcortical structures, including the brain stem, making simple acts of eating, swallowing and even breathing impossible  Symptoms of AD include memory impairment and atleast one neurological deficit, such as difficulty other in concentrating or confusional states, AD manifests first loss in a short term (recent memory)  Later stages AD affect long term memory distinction between episodic, semantic and procedural forms of long term memory  Loss of episodic memory is most noticeable in AD  Semantic and procedural memory are relatively well preserved in the mild to moderate stages of AF but eventually become impaired in the later stages may forget how to use a fork or even how to eat  Semantic = world knowledge, Procedural memory= praxis, the knowledge of how to do things  AD patients may not be able to remember many words from a list they were previously exposed to , they may respond more quickly to those words in subsequent though ( suggesting that the semantic network may be more intact than previously thought)  The visuaspatial disturbances in AD can result in an inability to find one’s way around the neighbourhood and sometimes even one’s own house  Some patients exhibit rapid personality change, often characterized by increases in aggression and inappropriate social behaviour  Eventually may loose all of self, difficulty swallowing, and even breathing, finally resulting in a death, more common secondary causes cause death in AD patients like pneumonia  Four types of alleles and individuals who have two copies of the fourth kind APOE, are at increased risk of AD  APOE4 may create a particularly sticky form of the lipoprotein which may help to create neurofibrillary tangles  APOE4 also predisposes individuals to stroke and there is increasing evidence that TIAs and strokes may also predispose individuals to AD  Heavy metals such as lead may also create neurofibrillary tangles  Estrogen replacement therapy may reduce the risk of AD and may slow declines once they appear, estrogen may also help treat it, people given skin patches of estradiol demonstrated enhanced cognitive performance compared to controls  Nicotine receptor sites in the brain, especially the entorhinal cortex, which is important in memory formation. Treatment with nicotine increases blood flow after about 33 week and laboratory studies have demonstrated improvement in memory performance with modest amounts of nicotine. However, nicotine is a double edged sword. Smoking damages the CVS and is a risk factor for stroke and previously mentionined vascular damage increases not only the probability of dementia but also worsens its manifestation. Nicotine injections although safer than smoking still have potential damage to arteries Parkinson’s Disease  Third most common neurological disorder  Characterized by loss of cells in the substantia nigra, an area in the brainstem which regulates dopamine levels  Too much Ach results in overcontraction of muscles  Characterized by motor tremors of hands, arms and legs, which decrease when performing voluntary tasks and during sleep. Increased muscle stiffness and decrease in the control of muscle contractions results in balance and gait problems as well as difficulty in completing voluntary movements  Treatment of Parkinson’s includes physical therapy and occupational therapy, fetal tissue implants have engendered a lot of interest  Freezing is a miscommunication between the nerves and the muscles that can make it difficult or even impossible to take a step forward Pseudodementia and Delirium  Depression can be associated with memory problems and result in a pseudodementia  Reversible if aqequately diagnosed  Dehydrations, malnutrition, overmedication and changes in living conditions such as bereavement Promoting age and optimal health - Care for CVS through exercise, diet and perhaps a daily aspirin - Exercise increases production of neurotrophic factors such as nerve growth factor - Sedentary individuals with the APOE4 allele showed nearly 4x the risk of cognitive decline - B vitamins are critical in promoting neural transmission and there is evidence that with age the small intestines in mammals are less able to absorb B12 leading not only to anemia but possible imparing neurological functioning as well - Antioxidants may be important with food like blueberries, strawberries and spinach (high antioxidant) - Hippocampus particularly susceptible to neuronal loss with age, suggest stress related -
More Less

Related notes for HSM 330

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.