Unit 8.1 - Homeostasis Flashcards
Homeostasis
The process of maintaining a constant internal environment
Negative Feedback
The homeostatic process which returns values to a set point, reversing the effects of any change within the system
Positive Feedback
The homeostatic process which amplifies any change in the system
Hormones
Chemical messengers released by endocrine glands and transported to target cells by the bloodstream
Alpha cells of Islets of Langerhans
Located in the pancreas and secrete glucagon into the bloodstream
Beta cells of Islets of Langerhans
Located in the pancreas and secrete insulin into the bloodstream
Insulin
A hormone that reduces blood glucose levels back to normal, storing glucose as glycogen for storage in the liver or used by muscles in aerobic respiration
Glucagon
A hormone that increases blood glucose levels back to their set point, stimulating the break down of glycogen to glucose which is released into the bloodstream
Glycogen
An energy storage polysaccharide formed in the liver of animals
Diabetes
A condition in which the homeostatic control of blood glucose has failed or deteriorated
Type 1 Diabetes
An autoimmune disease where the beta cells are damaged and the body no longer produces insulin
Type 2 Diabetes
Autoimmune disease where beta cells produce insulin but liver and muscle cells do not respond to insulin because the target cells are resistant to insulin
Thermoregulation
The process by which an organism maintains its body temperature within a narrow range
Peripheral Thermoreceptors
Thermoreceptors located within the skin which monitor body temperature
Thermoregulatory Centre
The part of the hypothalamus in the brain responsible for temperature control of the body
Thyroid Stimulating Hormone
When the body temperature drops, the pituitary gland in the brain secretes thyroid stimulating hormone which regulates the secretion of thyroxin from the thyroid gland
Thyroxin
A hormone secreted by the thyroid gland which is involved in the control of metabolic rate in the cells of the body
Adipose Tissue
Body fat which is found under the skin and acts as an insulator reducing heat loss
Endotherm
Animals that generate internal heat to maintain body temperature
Vasoconstriction
The narrowing/ consrtiction of the blood vessels to retain heat when body temperature drops
Vasodilation
The widening of the blood vessels to lose heat to the environment when the body temperature increases
Shivering
The involuntary contraction of muscles which generates heat to warm up the body when body temperature drops
Sweating
A response to an increase in body temperature whereby the sweat glands secrete fluid. As the fluid evaporates, heat is lost to the environment from the body
Uncoupled Respiration
Involves aerobic respiration producing heat and not ATP
Brown Adipose Tissue
A specialised type of adipose tissue which contains a high concentration of mitochondria
Hydrogen Bonds
Strong bonds that are formed between water molecules that take a lot of energy to overcome and are the reason water has such high latency
Polar Molecule
A molecule with an uneven distribution of electrons leading to one pole with slightly positive charge and another with slightly negative charge. Water is a polar molecule
Latent Heat of Vaporisation
The energy required to convert water from a liquid to a gas
