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Endocrine. Endocrine. Function Influences growth, metabolism, and homeostasis over prolonged periods Secretes hormone products into interstitial spaces which are then absorbed into the blood and transported throughout the body - PowerPoint PPT Presentation
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Endocrine
Function• Influences growth, metabolism, and homeostasis over prolonged
periods• Secretes hormone products into interstitial spaces which are then
absorbed into the blood and transported throughout the body• Hormonal control is much slower than nervous control, but the
effects of the endocrine system are much longer lasting
Key Features of Endocrine Glands• A rich capillary blood supply is necessary for secretion and
reception of hormones• Endocrine glands are, by definition, ductless• Organelles required to synthesize specific hormones are in great
supply
Hormone Classifications
Amino Acid Derivatives• Hormones derived from the amino acid tyrosine• Epinephrine, norepinephrine, and thyroxine
Polypeptide Hormones• Hormones with a peptide structure• Insulin, prolactin, NGF, EGF, GH, PTH, TSH, enkephalin,
TRH, ADH
Steroids• Hormones derived from cholesterol• Testosterone, cortisol, aldosterone, progesterone, estradiol
Pituitary Gland• Controlled by hypothalamus
• Infundibulum serves as a communication channel between the hypothalamus and pituitary
• The hypothalamohypophyseal neural tract is the passageway for two hypothalamic hormones to the posterior pituitary
• The hypothalamohypophyseal portal system carries hypothalamic hormones that regulate secretion from the anterior pituitary
• The anterior pituitary secretes hormones that regulate lactation, metabolism, growth, stress response, and reproduction
Pituitary Gland
A
B
A: Adenohypophysis (anterior pituitary): 1. Pars distalis. 2. Pars intermedia 3. Pars tuberalisB: Neurohypophysis (posterior pituitary): 1. Infundibulum 2. Pars nervosa
Adenohypophysis
A: Chromophobes
B: Basophilic chromophils Gonadotrophs– FSH and LH
Corticotrophs– ACTHThyrotrophs– TSH
C: Acidophilic chromophils Somatotrophs– GH Mammotrophs– Prolactin
ReviewFill in the missing hormones secreted from the pituitary or list their respective functions
Hormone Function
FSH
Causes follicle maturation and testosterone production in leydig cells
ACTH
Stimulates T3 and T4 secretion from thyroid
GH
Stimulates mammary glands
ADH
Smooth muscle contraction and milk letdown
LH
TSH
Prolactin
Oxytocin
Follicle maturation and spermatogenesis
Stimulates adrenal cortex
Controls growth
Stimulates water resorption
Pancreas
A
A: Islets of Langerhans contain four different cells: 1. α-cells 2. β-cells 3. δ-cells. 4. PP– cells
Pheochromocytoma
Source: http://en.wikipedia.org/wiki/Pheochromocytoma
• Neuroendocrine tumor of the adrenal medulla• Results in excessive secretion of catecholamines• Diagnosed by measuring plasma or urine levels of
catecholamines
Review
Anterior PituitaryFSHLHACTHTSHGHProlactin
Posterior PituitaryADHOxytocin
ThyroidT3 and T4Calcitonin
ParathyroidPTH
PancreasGlucagonInsulinSomatostatinPancreatic Peptide
StomachGastrin
AdrenalAldosteroneCortisolDHEA
Argentaffin CellCCKSecretinSerotonin
Know the following hormones, where they are secreted, their function, and target organ.