1. Hormones & Endocrine System

2. Introduction
Endocrine System – Sum of all hormone secreting cells and tissues
Endocrine Gland – ductless glands that secrete hormones directly into body fluids
Hormones – chemical signals that cause a response in target cells
Affect body tissues or other endocrine glands (tropic hormone)
Endocrine secretion is determined by Positive & Negative Feedback

5. Hormones Can affect 1 tissue, multiple tissues or entire body
Can also have a direct effect on non-endocrine tissues
OR affect other endocrine tissues
Called tropic hormones

6. Target Cell Receptors Cell-Surface Receptors Intracellular Receptors
Most common receptor for initiating a signal transduction pathway
Receptor  Transduction  Response
Intracellular Receptors
ONLY lipid-soluble ligands are able to pass through the membrane & bind intracellular receptors
Testosterone & estrogen (transcription factors)

7. Hypothalamus & Pituitary
Hypothalamus gets info from the brain or nerves
Hypothalamus initiates endocrine signal response
Pituitary – Anterior & Posterior
Posterior - Extension of the hypothalamus that stores and secretes hormones
Anterior – tropic hormones (say what???)

8. The Boss… Hypothalamus Receives signals from nervous system
Initiates endocrine signal response

9. Pituitary Gland
Note Hypothalamus

10. Anterior Pituitary Gland
Regulated by hypothalamus
Tropic hormones
Growth hormone (GH) & Thyroid- stimulating hormone (TSH) – seriously?
ACTH – Adrenocorticotropic hormone
Stimulates adrenal cortex to secrete glucocortocoids
Glucocortocoids raise the blood sugar level

11. Anterior Pituitary Gland (page 2)
FSH – (Follicle stimulating Hormone)
Stimulates development of ovarian follicles (female) or spermatogenesis in seminiferous tubules (male)
LH – (Luteinizing Hormone)
Triggers ovulation in females
Stimulates testosterone production in testes
PRL – (Prolactin)
Stimulates growth of mammary glands
milk production & synthesis of milk protein

12. Posterior Pituitary Oxytocin ADH – (Antidiuretic Hormone)
Stimulates uterine contractions
Stimulates milk release by mammary glands
ADH – (Antidiuretic Hormone)
Acts on collecting ducts in Kidneys
Increases water reabsorption from the filtrate

13. Thyroid & Parathyroid T3 – (Triiodothyronine) & T4 – (Thyroxine)
Stimulates & maintain metabolic processes
Calcitonin
Lowers calcium level in blood
Parathyroid Gland
PTH – (Parathyroid)
Raises calcium level in blood

14. Adrenal Gland
Epinephrine & norepinephrine – Increase metabolic level by:
Constrict blood vessels
Raise blood glucose levels
Glucocorticoids
Elevate blood glucose level
ACTH

16. Pancreas & Pineal Gland
Insulin – Lowers blood glucose level
Makes cells permeable to glucose
Glucagon – Raises blood glucose level
Breaks down glycogen
Pineal Gland
Melatonin – Involved in biological rhythms