D3.3 Homeostasis Flashcards
What is the positive feedback?
moves further from the original level (promoting the change)
What is the negative feedback?
it works towards stability (reducing the change)
What is homeostasis?
maintainance of stable internal conditions using negative feedback loops
What are exocrine glands in pancreas?
they release digestive enxymes through openings (ducts)
What are endocrine glands?
they release hormones directly into a bloodstream
Which cells secrete glucagon?
alpha-cells of the islets of Langerhans
Which cells secrete insulin?
beta-cells of the islets of Langerhans
What are pancreatic islets (endocrine cells)?
they are clusters of cells that produce insulin and glucagon
What is the role of insulin?
it stimulates glucose uptake in response to high glucose levels
What’s the role of glucagon?
it stimulates the liver to release glucose in response to low sugar levels
Which tissue responds to insulin and take up glucose?
liver cells, muscles and fat tissue
How the excess glucose is stored?
glucose is stored as glycogen in liver and muscles cells, or as fat in the fat tissue
Which tissue does glucagon promote and what happens in them?
liver and fat tissue breaks down stored glycogen and lipids and release to the bloodstream
What is thermoregulation?
process when body maintains stable temperature no matter the external environment
Where are processes of temperature control centered?
hypothalamus
What’s the role of hypothalamus?
-it receives the signals from peripheral thermoreceptors
-it stimulates pituitary gland to release TSH to stimulate thyroid gland
What’s the role of the thyroid gland?
it produced hormone thyroxin
What’s the role of thyroxin?
it increases metabolic rate of body cells and produce more heat
List mechanism that can regulate body temperature when it’s cold (3)
-skeletal muscle contractions (shivering)
-muscles in the skin contracts to make hair stand up to increase insulation
-vasoconstriction
What is vasoconstriction? What’s the function?
narrowing of blood vessels, keeps warm blood closer to vital organs
