Transcript Endocrine System

Endocrine System
 A chemical
communication system of
the body tissue

Types of communication
• Gap Junctions: similar to pores that are
connected, allow signal molecules to pass from
cell to cell
• Neurotransmitters
• Paracrines (Local hormones): a cell of tissue
that stimulates other cells around them with
secretion
• Hormones: chemical messenger that travels
through blood and stimulates target cells
Hypothalamus & Pituitary Gland
 Most
important glands in system they have
the largest effect on bodily functions
 They are closely related the pituitary sits
on a structure of the hypothalamus. The
hypothalamus often acts through the
neurohypophysis(posterior pituitary)
Hypothalamus
 Is
connected to the third ventricle of the
brain
 It regulates primitive body functions from
hydration to sex drive
 It produces 9 hormones five that stimulate
the pituitary, two that inhibits and two that
are secreted through the posterior
pituitary(oxytocin (OT), antidiuretic
hormone (ADH))
Pituitary Gland
 Made
of two parts the adenohypophysis
and neurohypophysis


Adenohypophysis: also known as the
anterior lobe. It has no nervous connection
it only responds to hormone interaction
Neurohypophysis: posterior lobe. It is only
¼ the size of the anterior lobe. It has
nervous connection and is not a true gland
it is a collection of different tissue.
Contains the hypothalamic stalk.
Pituitary Hormones
 Most
of the pituitary hormones are trophic
hormones
 Trophic hormones: stimulates other
endocrine organs to secrete their own
hormones
 Axis: the interaction between the
hypothalamus, pituitary and a remote
endocrine gland. (There are 3 different
axis)
Posterior Pituitary Lobe
 It
doesn’t produce any hormones it just
stores two OT and ADH
 OT: causes contraction of the uterus
darning Birth, contraction of lactation,
contraction during sexual response
 ADH: Controls hydration and
vasoconstriction
Anterior Lobe
 Follicle
Stimulating Hormone(FSH):
targets gonads causes the development of
eggs and sperm
 Luteinizing Hormone(LH): targets gonads
in females causes ovulation, in males
cause production of testosterone
 Thyrotropin(TSH): targets thyroid effects
metabolism
Anterior Lobe
 Corticotropin(ACTH):
targets adrenal
cortex effects sugar, fat and protein
metabolism (“cortisol”)
 Prolactin(PRL): targets mammary glands
increase in number and production
 Growth Hormone(GH): targets all tissue
is produced 1000 times more than any
other hormone promotes mitosis thus
tissue growth