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, ADHSteroids 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 tuberalis B: Neurohypophysis (posterior pituitary): 1. Infundibulum 2. Pars nervosa
E A D C B
Practice
Adenohypophysis A: Chromophobes B: Basophilic chromophils Gonadotrophs– FSH and LH Corticotrophs– ACTH Thyrotrophs– TSH C: Acidophilic chromophils Somatotrophs– GH Mammotrophs– Prolactin
A B C
Practice
Neurohypophysis A A: Pituicytes H: Herring Bodies
Review Fill in the missing hormones secreted from the pituitary or list their respective functions HormoneFunction 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
Thyroid A B 4 A: Follicular cells B: Parafollicular cells
Parathyroid A: Adipose tissue. C: Capillaries P: Principal or chief cells O: Oxyphil cells
A B
Practice
A B
Pancreas A A: Islets of Langerhans contain four different cells: 1. α-cells 2. β-cells 3. δ-cells. 4. PP– cells
Stomach A B Gastrin or G-cells A: Parietal cell. B: Chief cell.
Adrenal Gland ABCD A: Zona glomerulosa B: Zona fasciculata C: Zona reticularis D: Medulla
Practice
Clinical Connections
Pheochromocytoma Source: Neuroendocrine tumor of the adrenal medulla Results in excessive secretion of catecholamines Diagnosed by measuring plasma or urine levels of catecholamines
Enteroendocrine Cell A A: Argentaffin cells B: Central Lacteal B
Practice
Review Anterior Pituitary FSH LH ACTH TSH GH Prolactin Posterior Pituitary ADH Oxytocin Thyroid T3 and T4 CalcitoninParathyroid PTHPancreas Glucagon Insulin Somatostatin Pancreatic Peptide Stomach GastrinAdrenal Aldosterone Cortisol DHEA Argentaffin Cell CCK Secretin Serotonin Know the following hormones, where they are secreted, their function, and target organ.