1. The Endocrine System General Characteristics Hormone Action
Control of Hormonal Secretions
Stress and Health

2. Introduction
Endocrine system – includes cells, tissues and organs collectively called endocrine glands.
Secrete hormones – substances that diffuse from the interstitial fluid into the blood stream and eventually act on cells.
Paracrine hormones = only affect neighboring cells.
Autocrine hormones = affect only the secreting cell itself.

3. General Characteristics
Both the endocrine and nervous systems communicate with cells using chemical signals.
Hormones are to the endocrine system as neurotransmitters are to the nervous system.

4. Endocrine glands and their hormones help regulate metabolic processes.
They control
Rates of certain chemical reactions
Aid in transport of substances across membranes
Help regulate water and electrolyte balances.
Play vital roles in reproduction, development, and growth.

5. Glands we will look at:
Pituitary
Thyroid
Parathyroid
Adrenal
Pancreas

6. Hormones Amines – norepinephrine, epinephrine
Peptides – oxytocin, antidiuretic hormone,
Proteins – growth hormone, parathyroid hormone, prolactin
Glycoproteins – FSH, LH, TSH
*Steroids – Estrogen, testosterone, aldosterone, cortisol

7. Steroid Hormones events that occur when they enter a target cell
Diffuses through the cell membrane
Combines with a specific protein molecule
Resulting bound protein binds with a particular region of the DNA of the nucleus and activates transcription of specific genes into messenger RNA molecules
mRNA molecules enter the cytoplasm
mRNA molecules associate with ribosomes to direct the synthesis of specific proteins.

8. Analogy
Lobbyists in Washington, D.C.(Mr. Pierson story time)

9. Pituitary Thyroid Parathyroid Adrenal Pancreas
Glands
Pituitary
Thyroid
Parathyroid
Adrenal
Pancreas

10. Pituitary Gland Located at the base of the brain.
About 1 cm in diameter
Consists of an anterior lobe and a posterior lobe.
***THE BRAIN CONTROLS MOST OF THE PITUITARY GLAND’S ACTIVITIES.***

11. Anterior Pituitary Hormones
Growth hormone(GH)- stimulates cell growth in size and frequency.
Prolactin(PRL)- stimulates a woman’s milk production after the birth of an infant.
Thyroid-stimulating hormone(TSH)- controls thyroid gland secretion.
Adrenocorticotropic hormone(ACTH)- controls the manufacture and secretion of certain hormones from the outer layer of the adrenal gland.
Follicle-stimulating hormone(FSH) and Lutenizing hormone (LH)- also called gonadotropins because they exert their actions on the gonads (reproductive organs.)

12. Posterior Pituitary Hormones
Antidiuretic hormone (ADH)- diuretics are chemicals that increase urine production, so antidiuretics decrease urine production.
Oxytosin (OT)- deals mostly with uterine wall contractions for childbirth, but also functions as an antidiuretic.

13. Thyroid Gland
Vascular structure that consists of 2 large lobes connected by a broad isthmus.
Located below the larynx and anterior to the trachea.

14. Thyroid Hormones Thyroxine (T4) Triiodothyronine (T3)
**These have primarily the same function, except Triiodothyronine is 5 x’s more potent. They help regulate the metabolism of carbohydrates, lipids, and proteins.

15. They are the major factors determining how many calories the body must consume at rest in order to maintain life. = Basal Metabolic Rate (BMR)

16. Parathyroid Glands
Located on the posterior surface of the thyroid gland.
4 lobes: superior and inferior located on each of the 2 lobes of the thyroid.

17. Parathyroid hormone
Parathyroid hormone (PTH) – increases blood calcium concentration and decreases blood phosphate ion concentration.
Affects the bones, kidneys and intestines.

18. Adrenal Glands Closely associated with the kidneys.
A gland sits atop each kidney like a cap.
Consists of 2 parts:
Adrenal medulla = central portion
Adrenal cortex = outer part

19. Adrenal Medulla Hormones
Epinephrine – makes up 80% of adrenal medullary secretion.
Norepinephrine
**The effects of epinephrine and norepinephrine include increased heart rate, force of cardiac muscle contraction, increased breathing rate, elevated blood pressure, increased blood glucose, and decreased digestive activity.

20. Hormones of the Adrenal Cortex
Aldosterone – helps regulate the concentration of mineral electrolytes.
Helps maintain blood volume and blood pressure.
Cortisol – affects glucose metabolism. Also influences protein and fat metabolism.
Adrenal sex hormone = androgens and estrogens.
Supplement the supply of sex hormones from the gondads and stimulate early development of the reproductive organs.

21. Pancreas Flattened, elongated organ posterior to the stomach.
Consists of 2 major types of secretory tissue = endocrine and exocrine
Endocrine = Islets of Langerhans
Has a dual function:
Secretes digestive enzymes
Releases hormones

22. Hormones of the Islets of Langerhans
Glucagon – stimulates the liver to break down glycogen into glucose.
Insulin – stimulates the liver to form glycogen from glucose.