Class Notes (835,539)
Canada (509,225)
Health Studies (1,192)
HLTC23H3 (86)
R Song (30)
Lecture 5

HLTB02H3 LECTURE 5 notes.docx

5 Pages
60 Views
Unlock Document

Department
Health Studies
Course
HLTC23H3
Professor
R Song
Semester
Winter

Description
HLTB02 – LECTURE FIVE = ENVIRONMENTAL FACTORS Determinants of Human Growth:  Genetic  Endocrine system  Cultural factors  Environmental factors Environment Bergman‘s Rule: populations in colder climates are fenerally larger, with wider torsos/stockier stature, since reduced surface area relative to body weight limits heat loss Allen‘s Rule: populations in colder climates will have shorter arms and legs relative to height (to limit heat loss), while those in warmer climates will have longer arms/legs Note: improved nutrition, particularly in tropical regions, is now reflected in weaker climate-body size relationships than in past Environment:  Temp o Cold – requires higher rate of basal metabolic rate and robs body of energy used for growth  Energy used to keep body alive instead of growth  Altitude o Reduced oxygen  hypoxia, high solar radiation, cold, low humidity, high wings, rough terrain  Limits life and agricultural productivity o Hypoxia: most severe climatic stress  Less oxygen reach body tissues, can‘t be compensated by cultural or behavioural adaptions  Normal RBC saturated with oxygen 97%, at 3000 m, 90% only  Enough to disrupt cellular growth and metabolism  Ex. lower birth weight, Bolivia = 3.1 kg vs. 3.4 kg o Hypoxia + poor nutrition (synergy – must be together to have worse effect than either individually) = shorter lighter kids, reduced rate of growth  Other studies suggest the ooposite: better growth rates in high altitude vs. low altitude kids in same region  Poorer health and nutrition ‗cause malaria and parasites in lower altitudes (moist, warm, humid)  Seasonality o Temperate latitudes – climate can affect growth (spring births vs. fall births – could be sunlight)  Could act on human endocrine system directly, synchronize body‘s natural fluctuations in growth regulating hormone activity o Height: vitamin D, increases intestinal absortion of Ca and controls the rate of skeletal remodeling and mineralization of new bone  Hypothalamus releases hormones that stimulate/inhibit release of pituitary hormones  Pituitary gland releases hormones into circulation moving to specific target tissues  Thyroid hormones = thyroxin, triiodothyronine  Gonadal hormones = luteinizing hormone, follicle-stimulating hormone]  Adrenal hormones from kidneys = glucorticoids, ex. cortisol and androgens  Growth hormone from liver o Weight: can be product of food availability (seasonal food shortages)  Pollutants: o Natural and anthropogenic  Anthropogenic:  Air o Smoke – cooking, fire, coal-burning respiratory diseases, lung cancer, cigarettes  Second-hand smoke, during pregnancy  lower birth weight, altered fetal growth but continued exposure => respiratory conditions, Sudden Infant Death Syndrome (SIDS), ADHD, depression, cognitive impairment, later adult health problems, cancer o Smog – burning of fossil fuels, mixed with fog: photochemical smog – action of sunlight on chemicals found in air pollution (car exhaust) o Industrialization chemicals – CO, nitrogen oxides, asbestos, etc.  Water pollution – contamination from landfills and waste water from industrial plants; natural disasters and hurricanes o Chemical fertilizers, seepage down to water table, leaching from plant, to soil to earth to layers to water reservoirs and shit o Health effects: leukemia, cancer, neurological disorders  Solid Waste Pollution o leads to air and water – burned shit, crap seeps into water  poisoning, respiratory problems, etc.  Ex. Minamata Bay – methylmercury contamination of bay in Japan (aka Minamata disease)  CNS impairment due to severe mercury poisoning o Symptoms: numbness in limbs, muscle weakness, lack of coordination, vision and hearing damage, impaired speech, paralysis, coma and death o Congenital: affected fetuses, showing impairments similar to cerebral infantile paralysis (worse effect that on adults)  Lead Poisoning  Any age affected, children more vulnerable since nervous system
More Less

Related notes for HLTC23H3

Log In


OR

Join OneClass

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

Sign up

Join to view


OR

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.


Submit