endocrine system Flashcards
exocrine gland
glands that secrete their product through ducts onto body surfaces into the spaces within organs, or into a body cavity
endocrine gland
a gland that lacks ducts and releases its hormones into the fluid just outside the cell
endocrine system
the organ system along with the nervous system that functions in internal communication
hormones
a chemical messenger released by cells of the endocrine system that travels through the circulatory system to affect receptive target cells
target cell
a cell with receptors that recognize and bind a specific hormone
liquid soluble hormone
hormone that moves easily through the plasma membrane of cells and combines with receptors inside target cells
steroid hormones
a group of closely related hormones chemically derived from cholesterol
water soluble hormones
a hormone that cannot pass through the plasma membrane on its own so it influences the target cells indirectly through second messenger systems
first messenger
water soluble hormone that binds to a receptor on the plasma membrane of a target cell
second messengers
a molecule in the cytoplasm of a cell that is activated when a water soluble hormone binds to a receptor on the surface of the cell
negative feedback mechanisms
the homeostatic mechanisms in which the outcome of a process feeds back on the system shutting down the process
positive feedback mechanisms
the mechanisms by which the outcome of a process feeds back on the system further stimulating the process
pituitary gland
the endocrine organ connected to the hypothalamus by a short stalk
consists of the anterior and posterior lobes
hypothalamus
a small brain region located below the thalamus that is essential to maintaining a stable environment within the body
neurosecretory cells
specialized neurons that generate and transmit nerve impulses and make and secrete hormones
