F214 Flashcards
Negative feedback
The reversal of a change in the internal environment to return to a steady state or optimum position.
Homeostasis.@
Maintaining a stable internal environment despite external changes.
Positive feedback
Positive feedback is a process that increases any change detected by the receptors.
Endocrine gland
Endocrine gland is ductless and secretes hormone directly into blood.
Exocrine gland
A gland that secretes molecules directly into a duct that carries the molecules to where they are used.
Hormone
Hormones are molecules released into the blood which act as chemical messengers.
Target tissue
A group of cells that have receptors embedded in the plasma membrane that are complementary in shape to specific hormone molecules.
First messenger- adrenaline
The first messenger is the hormone that transmits a message around the body. I.e. Adrenaline
Second messenger- cyclic cAMP
The second messenger e.g. cAMP transmits a signal inside the cell.
Diabetes mellitus
Is a disease in which the body is no longer able to control its blood glucose concentration.
Define the term excretion
Removal of toxic products of metabolism.
Deamination
Is the removal of toxic amine group from unwanted amino acids.
Autotroph (tick)
Organism that use inorganic molecules to make complex organic molecules
Heterotroph (tick)
Has to get its organic molecules from another organism.
Photosynthetic pigments
Are molecules that absorb light. Each pigment absorbs a range of wavelengths in the visible region and has its own distinct peak of absorption. Other wavelength are reflected.
