1. By Debra Kuhn & Katrine Viscaya
Endocrine System
By Debra Kuhn & Katrine Viscaya

2. What is the endocrine system?
The word Endocrine derives from Greek origin
The endocrine system is the collection of glands in which each gland secretes a different type of hormone that regulates:
Metabolism
Growth & Development
Tissue Function
Sexual Function
Reproduction
Sleep & Mood
Ect.

3. What are hormones? What do they influence?
Hormones: They are substances secreted by endocrine glands into the internal environment.
Influences: They diffuse from the interstitial fluid into the bloodstream and then act on target cells. They regulate physical and chemical processes. They may act on several organs throughout the body.

4. Exocrine vs. Endocrine Exocrine Endocrine
These glands secrete products into ducts that open onto surfaces (outside environment)
They have ducts to carry hormones
Sub-classifications: Multicellular and Unicellular
Multicellular glands include:
Holocrine Glands
Apocrine Glands
Merocrine Glands
Endocrine
Glands from this system secrete their products into tissue or blood (Inside the Body).
These glands are ductless
The response is slower because hormones travel through blood
The duration of the response in motion is longer because kidneys filter blood.

5. What makes up the Endocrine System
Hypothalamus
Pituitary Gland
Thyroid
Parathyroid
Adrenal Glands
Pineal Body
Reproductive (Ovaries and Testes)
Pancreas
Thymus

6. Regulation of Hormone Secretion
Every time a Hormone is secreted, it is due to Negative Feedback Mechanisms. These mechanisms include
The Hypothalamus: The Hypothalamus regulates anterior pituitary glands release of hormones that tell other Endocrine glands to release their hormones.
The Nervous System
The Changing level of substance in plasma: Another group of glands responds directly to changes of the composition of the internal environment

7. Nervous System Explained
The Nervous System stimulates some glands directly which then release hormones to the target cells that cause the action of hormone response.

8. Steroid vs. Non-steroid
Soluable (Soluable to Lipids so they can diffuse into cells easily)
The Steroid Hormone binds a specific Hormone Molecule which is the receptor for that Hormone
Hormone Receptor Complex binds within the Nucleus to particular regions of the target cells DNA
This activate Transcription
RNA molecules leave the Nucleus and enter cytoplasm
mRNA associate with Ribosomes to direct the synthesis of specific proteins

9. Steroid Vs. Non-Steroid
A hormone binds its receptor
This hormone receptor complex activates a protein called “G” Protein
The “G” Protein activates the enzyme Adenylate Cyclase
Activated Adenylate Cyclase catalyses the circularization if ATP in the Cytoplasm into cAMP
cAMP activates another set of enzymes called Protein Kinases which transfer Phosphate group from the ATP to their substrate molecule

10. 1. The Hypothalamus Location: Above the brain stem
Controls the release of the 8 major hormones
Controls body temperature, Food and Water intake, hunger, thirst, sexual behavior, daily cycles in psychological state, and the meditation of emotional responses

11. 2. Pituitary Gland Location: Beneath the Hypothalamus
“Master Gland” – Most important gland of the Endocrine System
Hormone production
Divided into two parts (Anterior and Posterior)
Controls secretion of Endorphins
Also controls Ovulation & Menstrual Cycle for women

12. 3. Thyroid Gland
Location: Frontal part of Lower neck (Butterfly Shape)
Produces Thyroxine & Triiodothyronine = controls rate of cell burning of food (energy)
Metabolism
Helps kids/teens bone grow and develop
Develops the brain and nervous system in kids

13. 4. Parathyroid Gland Location: Attached to Thyroid
Releases Parathyroid Hormones = regulates level of calcium in blood with help of calcitonin (produced in Thyroid)

14. 5. Adrenal Gland (Two Parts)
Location: On top of each Kidney
Outer (Adrenal Cortex)
Produces Corticosteroids = Regulates salt and water balance in the body, its response to stress, metabolism, immune system, and sexual development and function
Inner (Adrenal Medulla)
Produces Catecholamines = (Adrenaline), this increases blood pressure and heart rate when the body experiences stress

15. 6. Pineal Gland Location: Middle of the Brain
Secretes Melatonin = Regulates sleeping Schedule (when you sleep at night and when you wake up in the morning)
Involved in daily biological cycles

16. 7. Reproductive Glands Males Females
Gonads are main source of sex hormones
Location: Testes in Scrotum
Secrete hormones called androgen
Females
Gonads are main source of sex hormones
Location: Ovaries in the Pelvis
Secrete hormones estrogen and progesterone

17. 8. Thymus Location: Behind Sternum & Between lungs
This Gland is only active until puberty, and after puberty it starts to shrink and is replaced by fat
This gland stimulates the development of T cells =
T cells are a type of white blood cells which helps protect the body from infection and viruses

18. 9. The Pancreas Location: Behind the Stomach Two main functions:
exocrine function - helps in digestion
endocrine function - regulates blood sugar

19. Hormones Released by Glands

20. Regulation of Hormone Secretion
Hypothalamus regulates the anterior pituitary gland’s release of hormones that stimulate other glands to release.
Nervous system stimulates some glands directly (i.e. the adrenal medulla which secretes hormones in response to sympathetic nerve impulses)
Other glands respond directly to changes in the internal environment (i.e. blood glucose level so pancreas secretes insulin or glucagon)

21. Negative Feedback Mechanisms
Cycle:
Stimulus (ex. Blood Glucose)
Receptors (ex. Beta Cells)
Control Center (Nerve cells in Brain)
Effector (Insulin)
Response (Blood Drops)

22. Diseases Diabetes Hypothyroidism Hypoglycemia
Body does not process glucose properly, due to lack of insulin or the body is not working effectively with the insulin
Hypothyroidism
Thyroid gland doesn’t produce enough thyroid hormone, which may cause many body functions to slow or shut down completely
Hypoglycemia
Low blood glucose or low blood sugar, occurs when blood glucose drops below normal. Typically happens as result to diabetes treatment because too much insulin is taken
Hormones can also impact bones, in diseases such as osteoporosis and osteomalacia (rickets) in which bones soften