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15 terms

ib bio 6.5 pp 28-36

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Thermoregulation
Human core body temperature needs to remain at around 37 degrees Celcius.
Hypothermia
When the body's temperature drops too low for metabolic reactions to occur. Death below 32 degrees celcius.
Hyperthermia (heat stroke)
Occurs when the body's core temperature gets too high and the tissues are damaged. Above 40 degrees celcius is deadly.
Heat generated in the ___ and carried around the body through the _____. Heat is lost through the__. The greater the SA to Vol ratio,____.
liver;blood;skin; the faster the rate of heat loss.
Hypothalamuss
controls hot and cold reactions
Too Cold
Arterioles constrict (vasoconstriction);
Sweat glands close;
Hair stands up, traps layer of air;
Muscle Spasms (Shivering);
Blood warms;
Thyroid hormones increase the body's metabolic rate;
Too Hot
Arterioles dilate (vasodilation);
Sweat glands open;
Hairs lie flat, no boundary layers;
blood cools;
breathing rate increases;
The hypothalamus and pituitary link the nervous and enocrine systems:
Cold temperature changes are detected by cells in the skin and relayed through the hypothalamus; HP relays signal to pituitary (releases TSH); TSH carried in the blood and acts on thyroid and releases the thyroid hormone;carried through the blood an acts on most cells;leads to increased heat production through metabolism
Blood Glucose
Maintained through the actions of the pancreas and liver
The control of blood glucose
Pancreatic cells monitor bg;
Absorption of glucose from digestion in the intestine increases blood sugar/fasting reduces blood sugar; Glucoregulation is an example of negative feedback;
Uses hormones, insulin, and glucagon.
If blood glucose is too high
Beta cells of pancreas produce insulin; insulin stimulates uptake of glucose cells (muscle);insulin stimulates liver/fat cells to store glucose as glycogen; leading to decrease in blood glucose.
If blood glucose is too low
Alpha cells of pancreas produce glucagon; glucagon stimulates liver to break glycogen into glucose; leads to increased blood sugar.
Diabetes
Reduced ability to control blood glucose through insulin
Type One Diabetes: Early Onset
Hereditary,weak relationship;Trigger needed (illness);Beta cells destroyed;insulin production stops
Type Two Diabetes:Adult Onset
Hereditary,strong relationship; Related to obesity and poor diet;Fewer insulin receptors in liver;less sensitivity to insulin,(insulin does not work as well)