1. Endocrine Glands
Secretion
and
Action of Hormones

2. Classic Definition of a Hormone
Hormone - Chemical messenger produced by a ductless gland or tissue and carried in the blood/lymph to a target organ where it effects a change in cellular activity.
EffectorCell 1
Target
Cell 2
Capillary

4. Endocrine Glands Testis in Male Adrenal Gland Hypothalamus Ovary
Kidney
Pituitary
Located at
base of brain
Thyroid
Parathyroid
Testis in
Male

5. Ectocrine
Flehmen
Pheromones: A chemical substance that is liberated by one animal and causes a relatively specific behavior modification in a recipient animal following its chemoreception

6. Structural Classes Amines: Peptides, Polypeptides and Proteins
Hormones derived from tyrosine and tryptophan.
Peptides, Polypeptides and Proteins
Polypeptides
Chains of < 100 amino acids in length.
ADH.
Ex: Adrenalcorticotropic Hormone (ACTH) – 39 amino acids
Peptide - Few - Several amino acids
Ex: Gonadotropin Releasing Hormone (GnRH) - 10 amino acids
Oxytocin - 8 amino acids
Protein hormones:
Polypeptide chains with > 100 amino acids.
Growth hormone, Insulin.
Prolactin amino acids

7. Structural Classes
Glycoprotein - Protein hormone with carbohydrate molecules
Steroids
Lipids derived from cholesterol
Are lipophilic (fat loving; can diffuse through plasma membrane) hormones.
Ex – testosterone, estradiol, progesteone, and cortisol

14. a. GnRH from the hypothalamus stimulates the release of FSH and LH from the anterior pituitary. b. FSH stimulates production of estradiol and inhibin by granulosa cells in the ovarian follicle. c. Inhibin selectively inhibits release of FSH  d. When progesterone is low, high concentrations of estradiol stimulate a greater surge of GnRH, FSH, and LH, a positive feedback control. e. LH stimulates production and release of progesterone by granulosa cells in the corpus luteum f. High concentrations of progesterone inhibit the release of GnRH, FSH, and LH, a negative feedback control.