ch 17 endocrine
Terms in this set (20)
1) differentiation of reproductive and CNS in fetus.
2) stimulation of growth and development
3) coordination of the male and female reproductive system
4) maintenance of internal environment
5) adaptation to emergency demands of body
most common feedback system in the endocrine system
thyrotropin-releasing hormone (TRH)
a thyroid stimulating hormone (TSH) secretes from the anterior pituitary is stimulated by TRH from the hypothalamus and by decreased serum levels of the thyroid hormones T3 and T4. secretion of TSH stimulates the synthesis and secretion of thyroid hormones. Increasing levels of T3 and T4 then generate negative feedback on the pituitary and hypothalamus to inhibit TRH and TSH synthesis.
target cell functions
1) recognize and bind specifically and with high affinity to their particular hormones
2) initiate a signal to appropriate intracellular effectors
low concentrations of hormone increase the number of receptors per cell
high concentrations of hormone decrease the number of receptors
Hormone effects- direct effects
obvious changes in cell function that result specifically from stimulation by a particular hormone
Hormone effects- permissive effects
less obvious hormone-induced changes that facilitate the maximal response or functioning of a cell
located in the plasma membrane or in the intracellular compartment of the target cell
high molecular weight, cannot diffuse across the plasma membrane
easily diffuse across the plasma membrane and bind to cytosolic or nuclear receptors
secreted into the bloodstream and carries a message to the target cell.
is generated by the first messenger, is small like cAMP, cGMP, calcium, and tyrosine kinase system. Transduces the signal from the receptor to the cytoplasm and nucleus of the cell and mediates the effect of the hormone on the target cell.
contains special neurosecretory cells and is located at the base of the brain. Connected to the pituitary gland by the pituitary stalk.
located in the sella turcica. Has two distinct lobes; anterior and posterior.
major component of the anterior pituitary and is the source of the hormones of the anterior pituitary
thin layer of cells on the anterior and lateral portions of the pituitary stalk
lies between the two. Disappears in adulthood and the individual cells are distributed diffusely throughout the pars distalis and pars nervosa of the posterior pituitary.
Anterior pituitary is composed of two main cells
1) chromophobes; nonsecretory 2) chromophils; secretory cells
secreted from anterior pituitary and affects the physiological function of specific target organs