D3.3 Homeostasis | Quizlet

Brown adipose tissue

A type of fat tissue that has a greater number of mitochondria than the more common white adipose tissue. It can perform uncoupled cell respiration to generate heat

Alpha cells (α-cells)

endocrine cells in the pancreas that synthesize and secrete glucagon, which signals target cells to hydrolyse glycogen, elevating the glucose levels in the blood.

Beta cells (β-cells)

cells in the pancreas that make insulin, a hormone that signals target cells to absorb more glucose from the blood, lowering blood glucose levels

Blood glucose

Normal adult blood levels range from 70 to 115 mg/100 ml.

Diabetes

a group of metabolic diseases in which a person has high blood sugar, either because the pancreas does not produce enough insulin, or because cells do not respond to the insulin that is produced.

Glucagon

a hormone secreted by the pancreas that raises blood glucose levels by initiating hydrolysis of glycogen molecules, mainly in the liver

Hormone

a substance, usually a peptide or steroid, produced by an endocrine gland and transported by the blood to another tissue to affect physiological activity, such as growth or metabolism.

Hypothalamus

a region of the brain that functions as the main control centre for homeostasis.

Insulin

a hormone that lowers blood glucose levels by promoting the uptake of glucose by most body cells and the storage in the liver as glycogen

Metabolic rate

the speed of chemical processes (and heat generation) occurring within a living cell or organism.

Negative feedback

when the system responds to counteract the initial change (more--> less / less --> more) - leads to stability

Pancreas

a gland in vertebrates that has both an exocrine (secretes pancreatic juice into small intestine) and endocrine (secretes insulin and glucagon into the bloodstream) function.

Positive feedback

when the system responds to a change by causing further change in the same direction as the initial change (more --> more / less --> less); leads to increasing changes

Thyroid gland

an endocrine gland at the base of the neck that makes and stores thyroxine hormones that help regulate the rates of metabolism, (also growth, and development)

Thyroxin

an iodine-containing hormone produced by the thyroid gland, that increases the rate of cell metabolism (and regulates growth).

Diabetes type I

Hereditary autoimmune condition where the beta cells of pancreas are destroyed and the person cannot produce enough insulin to regulate blood glucose effectively

Diabetes type II

Condition in which a person has high levels of insulin and glucose in the blood but the target cells do not respond to the insulin (insulin insensitivity) - related to lifestyle factors

endocrine gland

a ductless gland that secretes hormones directly into the bloodstream

vasoconstriction

Contraction of muscles in the walls of arterioles to reduce blood flow - in the skin this causes surface temperature to drop

vasodilation

relaxation of the muscles in the walls of arterioles that increases blood flow - in this skin this causes surface temperature to rise

Piloerection

Contraction of hair erector muscles in skin that make hairs / fur stand upright, visible in humans as goosebumps