Glands - Endocrine and Exocrine Flashcards
what is the endocrine system responsible for
the synthesis and secretion of chemical messengers known as hormones
how do hormones travel
through the bloodstream
what do hormones act upon
specific target organs and tissues
how do some other hormones act
locallyy - they arrive at the site via microcirculation
what are endocrine glands composed of
islands of secretory epithelial cells, intervening support tissue
what are endocrine glands rich with
blood and lympathic capillaries
where do secretory cells discharge hormones
into the space where it is rapidly absorbed into the circulatory system
what are some chemicals that act as hormones
- protein and glycoprotein molecules
- small peptide molecules
- amino acid derivatives
- steroids derived from cholesterol
what are the three main parts of the endocrine system
the major endocrine organs
the endocrine components within other solid organs
diffuse endocrine system
what is the major function of major endocrine organs
the synthesis, storage and secretion of hormones
what are examples of major endocrine organs
thyroid and adrenal glands
some endocrine glands are components within other solid organs. what organs?
- pancreas
- ovary
- testis
- kidney
what is meant by the diffuse endocrine system
scattered individual hormone cells within an extensive epithelium
what is the major function of the diffuse endocrine system
paracrine
what do paracrine hormones do
act on adjacent non endocrine cells, rather than entering the bloodstream and producing systematic effects
what is the pituitary gland
- a small gland at the base of the brain beneath the third ventricle.
- it is divided into anterior and posterior parts with different embryological origins, functions and control mechanisms
what controls secretion of the pituitary hormones
hypothalamus - this is under the influence of nervous stimuli from higher centres in the brain
what are the two main functional groups of pituitary hormones
hormones that act directly on non endocrine tissues
hormones that modulate the secretory activity of the other endocrine glands
what are some examples of pituitary hormones that act directly on non endocrine tissues
growth hormone
prolactin
ADH
oxytocin
MSH
what are some examples of pituitary hormones that modulate the secretory activity of other endocrine glands
thyroid stimulating hormones, ACTH, gonadotrophic hormones, follicle stimulating hormone, LH
which glands can be described as pituitary dependent endocrine glands
thyroid gland
adrenal cortex
gonads
what is the most common disease of the pituitary gland
pituitary adenoma - benign tumours
what is pituitary adenoma a disease of
the pituitary gland
what is the thyroid gland
an endocrine gland found on the upper part of the trachea, shaped like a butterfly