1. 10.1-10.2 Hormones and The Endocrine System

2. Learning Goals
Understand where all hormones are produced and from what body part they come from
Understand each hormones effect
Understand the endocrine system
Textbook pg

3. History is Cool 1889 Joseph Von Menring and Oscar Minkowski, France
Removed pancreas in dogs
Dogs were fatigued—symptoms of diabetes
Ants attracted to dog urine—lots of glucose not being absorbed into dogs
Concluded pancreas controls blood sugar somehow

4. 10.1: Hormones
Hormones are chemical regulators that are produced in one part of the body but affect cells in another part of the body, by travelling through the blood
Chemicals produced in glands and secreted directly into blood are endocrine hormones
Hormones are classified by their activation site
Non-Target Hormones (stimulate various parts of the body)
Examples: growth hormone, insulin, epinephrine
Target Hormones (stimulate specific sites of the body)
Examples: parathyroid hormone, gastrin
Receptors

5. Become active later on Released as prohormones in the inactive form
Ex. Angiotensinogen is released by liver
Angiotensin-converting enzyme (ACE) acts upon it
Converted to angiotensin
Blood pressure rises
FYI: medications to suppress ACE prescribed to reduce blood pressure

6. Various areas in the body produce hormones to comprise the endocrine system
Hormones can affect cells when they combine with cell receptors
Not all cells have the same receptors and some cells have more receptors than others for a specific hormone

7. Types of Hormones 1. Protein hormones
Chains of varying lengths of amino acids
Water soluble/ hydrophillic
Can’t cross phospholipid bilayer
Must bind to receptor on the bilayer to effect change

8. Ex. Protein hormone glucagon and receptors in liver cells results in phosphorylation reactions causing glygogenglucose
Ex. Includes insulin and growth hormone

9. Types of Hormones
2. Steroid hormones
Are lipids made from cholesterol
Water insoluble/ hydrophobic
Crosses phospholipid bilayer to effect change within the cell
Complex attaches to promoter in DNA
Ex. Includes male and female sex hormones and cortisol

10. 10.2 Endocrine System
The endocrine system is a system of glands that are located in various parts of the body
They produce hormones that are secreted into the blood which carries them throughout the body

11. Hypothalamus
Different from other glands since it is in the brain and thus part of the nervous system
Neurons inside of it produce a hormone (neurohormone)
Sent to pituitary gland to control the production of hormones
Uses negative feedback systems to control how the hypothalamus releases hormones

12. Pituitary Gland
Often called the “master gland” as it controls over the other endocrine glands
Connected to hypothalamus
Produces and stores hormones
Comprised of two lobes:
1. Posterior Lobe
Stores and releases Oxytocin, ADH
2. Anterior Lobe
Everything else

14. Examples of Feedback Loops
In water balance note
Review ADH (posterior lobe of pituitary)
Review Angiotensin (liver)

15. History is Cool Parathyroid glands are found on the thyroid gland
When first attempting to figure out what they thyroid did, it was tricky...
When they removed the thyroid in animals to see the effect, they also, inadvertently, removed the parathyroid, too which created confusing results

16. Thyroid Gland
The thyroid is located is the front of the throat and has a bowtie shape
Produces thyroxine (“T4” b/c it has four iodine atoms in it) and triiodothyronine (T3)
Regulates metabolism

17. Hyperthyroidism Hypothyroidism Overactive
High metabolism = weight loss, increase in body temp, nervousness
Hypothyroidism
Underactive
Low metabolism = fatigued, weight gain, dry skin, edema

18. Goiters Iodine needed to produce thyroid hormones
Not enough iodine = not enough thyroxine
No thyroxine = more TSH produced
Negative feedback loop shuts down
thyroid swells b/c overstimulated

19. Parathyroid Gland Four glands on anterior side of the thyroid gland
Produces Parathyroid Hormone (PTH)
Regulates calcium levels in blood

20. Parathyroid Gland

21. Adrenal Hormones Adrenal glands on kidney
Adrenal medulla releases ephinephrine and norepinephrine

22. Epinephrine/Norepinephrine
signals fight or flight response
Increases glycogen conversion to glucose and glucose uptake, heart rate, blood pressure...

23. More Adrenal Hormones
Adrenal cortex releases aldosterone to increase salt retention in kidneys
Aldosterone is a mineralcorticoid
Also releases cortisol, a glucocorticoid (promotes breakdown of fats + glycogen  glucose in liver!); stress hormone

24. Pineal Gland Third eye in reptiles on skull surface
In humans, it is located deep in the brain
Melatonin hormone which regulates circadian rhythms in humans