1. Endocrinology: Other Endocrine Glands and Hormones (40.3)
By Megan Christovich, Isabelle Garcia, Gibson Grimm and Walker Miller 2A
IS THAT THE WALKER MILLER (MINI) omg he’s adorable AWWW

2. Other Endocrine Glands and Hormones: Outline
Thyroid and Parathyroid Glands
Thyroid Gland
Effects of Thyroid Hormones
Calcitonin
Parathyroid Glands
Antagonistic Hormones
Adrenal Glands
Glucocorticoids
Mineralocorticoids
Malfunction of the Adrenal Cortex
Pancreas
Diabetes Mellitus
Types of Diabetes
Testes and Ovaries
Pineal Gland
Thymus Gland
Other Hormones
Leptin
Erythropoietin
Local Hormones

3. Thyroid and Parathyroid Glands
Thyroid gland, one of the main glands of the endocrine system, is located in the neck
Attached to the trachea, located just below the larynx
Parathyroid glands on/within posterior of thyroid

4. Thyroid Gland Again, the thyroid is the largest endocrine gland
Reddish, made of two joined lobes
Composed of follicles filled with thyroid hormones.

5. Effects of Thyroid Hormones
To produce the two thyroid hormones (triiodothyronine and thyroxine), the thyroid needs and seeks iodine.
If iodine isn’t present in diet, the thyroid can’t produce hormones and enlarges to form simple goiter.
Iodized salt prevents goiters.

6. Effects of Thyroid Hormones (cont.)
Job of thyroid hormones to increase metabolic rate of body
No target organ; stimulate all cells to break glucose faster
Congenital hypothyroidism results when thyroid doesn’t properly develop.
AKA cretinism: those affected are short/stocky, have had extreme hypothyroidism since child
Thyroid hormone therapy helps start growth, but if first two months of life pass w/o treatment, mental retardation results.
In adults, hypothyroidism (not producing enough thyroid hormones) results in myxedema---lethargy, weight gain, slow pulse, puffy skin.
Injection of thyroid hormones restores normal function and appearance for myxedema.

8. Effects of Thyroid Hormones (cont.)
Hyperthyroidism: too many thyroid hormones produced
Most commonly caused by Graves’ disease (genetically predisposed; infectious trigger)
Overactive thyroid forms exophthalmic goiter: eyes protrude, eye muscles swell
Hyperactivity, nervousness, insomnia.
Negative feedback mechanism used for homeostasis
Treatment: radioactive iodine used to remove part of the thyroid.

9. Calcitonin
Calcium (Ca^2+) is needed for nerve transmissions, muscle contraction, blood clotting---regulated by calcitonin.
Thyroid secretes calcitonin whenever blood calcium level rises: calcitonin pushes calcium into bones by reducing osteoclast activity.
When blood calcium level returns to normal, calcitonin is inhibited
Too low: stimulates release of parathyroid hormones.

10. Parathyroid Glands
Four parathyroid glands located on posterior of thyroid.
Produce parathyroid hormones (PTHs) that cause blood calcium level to increase when too low.
Increase osteoclast activity, calcium release from bones, calcium reabsorption by kidneys, bringing blood calcium to normal until hormone no longer secreted.
Hypoparathyroidism: too little PTH production, blood calcium level plummets, condition called tetany results.
Body constantly shakes from muscle contraction; overexcitable nerves.
Hyperparathyroidism: blood calcium level soars, bones become abnormally soft and fragile.

11. Antagonistic Hormones
Calcitonin and PTH are known as antagonistic hormones because their actions are diametrically opposed
Calcitonin secreted when blood calcium level too high (decreases it)
PTH secreted when blood calcium level too low (increases it)
Antagonistic hormones also found in other organ systems
Ex: liver secretes insulin and glucagon, which perform opposite jobs on blood glucose level.

12. Adrenal Glands Two triangular-shaped glands located atop kidneys.
Inner portion (adrenal medulla) and outer portion (adrenal cortex)--- no connection between
Hypothalamus controls both portions; stress prompts this stimulation.
Epinephrine (adrenaline) and norepinephrine (noradrenaline) produced by adrenal medulla activate sympathetic nervous system
Glucose breaks down to ATP, reserve glycogen activated, heart rate speeds up w/contraction.
Adrenal cortex: produces mineralocorticoids and glucocorticoids for a long-term response to stress.
Also secretes a small amount of sex hormones.

13. Glucocorticoids
Regulate carbohydrate, protein and fat metabolism, leading to increase in blood glucose level.
Most significant glucocorticoid is cortisol, raises blood glucose level
1. By stimulating the breakdown of proteins into glucose (enters blood through liver)
2. By prioritizing fatty acid metabolism over carbohydrates (spares glucose)
Cortisol also counteracts inflammation in the form of cortisone.
High levels of cortisone can suppress inflammatory responses to pain sites in arthritis
But also suppresses immunity and makes one more susceptible to infection.

14. Mineralocorticoids
Regulate salt and water balance, leading to increases in blood volume and blood pressure.
Most significant mineralocorticoid is aldosterone, affects kidney while promoting renal (in kidneys) sodium absorption and potassium excretion.
When blood sodium (& pressure) low, kidneys secrete renin, an enzyme converting plasma protein angiotensinogen to angiotensin I; lungs convert this to angiotensin II, stimulated adrenal cortex to result aldosterone.
This is called renin-angiotensin-aldosterone system---raises blood pressure
1. Angiotensin II constricts arterioles and 2. Aldosterone causes kidneys to reabsorb sodium-- -when blood sodium level rises, water reabsorbed and blood pressure levels.

15. Mineralocorticoids Aldosterone has an antagonistic hormone.
When heart atria are stretched by high blood volume, cardiac cells release hormone called atrial natriuretic hormone (ANH) which inhibits aldosterone secretion.
This causes sodium excretion (naturesis) as well as water excretion, so blood pressure returns to normal.

16. Malfunction of the Adrenal Cortex
When hyposecretion leads to low level of adrenal cortex hormones, Addison’s disease results.
Excessive adrenocorticotropic hormone (ACTH) leads to bronze skin (too much melanin), weight loss, weakness, low blood pressure.
Without cortisol, glucose can’t replenish during stress; thus, death occurs.
Lack of aldosterone⇢low sodium and water levels, low blood pressure, dehydration⇢death
Treated w/corticosteroids; lifelong condition; doubles mortality rate
JFK famously had Addison’s (and hid it) along with hypothyroidism.

17. Malfunction of the Adrenal Cortex
When hypersecretion leads to high levels of adrenal cortex hormones, Cushing’s syndrome results.
Excess cortisol: higher diabetes risk as fat deposited quicker; obese torso
Excess aldosterone: blood becomes basic pH; moon-shaped face; high blood pressure (hypertension)
In women, masculinization occurs due to excess adrenal male sex hormones.
Most cases caused by overdosing on corticosteroids; must wean off.
Or caused by adenoma of adrenal gland; removed with surgery.

18. Pancreas
Slender, pale organ in the abdomen between kidneys and near duodenum of small intestine
Exocrine tissue secretes digestive juices-> small intestine
Endocrine tissue (Pancreatic Islets) secrete insulin and glucagon
Insulin is secreted usually after eating, when blood glucose levels are high
In liver and muscle cells, glucose is stored as glycogen. In muscles cells, breakdown is energy for protein metabolism. In fat cells, breakdown supplies glycerol for fat formation
Glucagon is secreted usually between eating, when blood glucose levels are low
Raises levels by stimulating liver to break down glycerol into glucose and use fat and protein for energy. Adipose tissue breaks down fat into glycerol and fatty acids, used by liver as substrates to make glucose.

19. Diabetes Mellitus
This hormonal disease occurs when liver cells don’t take in as much glucose as they should.
This causes the person to get really hungry. Glucose, because it is in excess, is excreted in urination- which makes the diabetic thirsty.
Normally after an intake of glucose, blood glucose levels would increase for a few hours then return to normal. In a diabetic, the glucose levels are high for hours.

20. Types of Diabetes
A person with type 1 has to have daily insulin injections, which are complicating because missing one or overdosing can result in hypoglycemia (low blood sugar)
Perspiration, pale skin, shallow breathing, and anxiety. Potential unconsciousness
A type 1 diabetic can receive a working pancreas transplant.
An experimental procedure is to place an artificial organ- a capsule with pancreatic T cells that allows insulin to get out but prevents antibodies and T- lymphocytes from getting in.
Type 1: The pancreas is not producing Insulin.
The presence of a virus cause cytotoxic T cells to destroy pancreatic islets
Body turns to metabolism of fat which leads to buildup of ketones in the blood, ketonuria, which leads to acidosis which can lead to coma or death.

21. Types of Diabetes
Type 2 diabetes can be controlled or prevented by maintaining a low fat, low sugar diet, and exercising regularly
There are also pills/medications to take that stimulate the pancreas making it secrete more insulin and enhances the metabolism of glucose in liver and muscle cells.
Type 2: the patient is obese. The adipose tissue impairs insulin receptor function
Normally , insulin binds to a receptor to increase glucose transporters in the plasma membrane.
Long term complications (of both): blindness, kidney disease, and cardiovascular disorders including atherosclerosis, heart disease, stroke, and reduced circulation which can lead to gangrene in arms and legs.

22. Testes and Ovaries Testes: located in the scrotum
Produce androgens (testosterone)
Hormone increases during puberty, causing male sex characteristics to mature. Includes growth of penis, enlargement of larynx and vocal cords, and hair growth
Responsible for muscular strength in men-- anabolic steroids
Ovaries: located in the pelvic cavity
Produce estrogens and progesterone
Estrogen is largely responsible for egg maturation and growth of uterus and vagina.
Both hormones are responsible for breast growth and regulation of uterine cycle.

23. Pineal Gland Thymus Located in the brain!
Secretes melatonin, especially at night
Regulates circadian rhythm
Thymus
Located just beneath the sternum.
Is most active in childhood years, becomes fatty with age.
Transforms lymphocytes from bone marrow to T lymphocytes, which work toward immunity
Lobules of thymus are lined with epithelial cells that secrete thymosins, which aid in differentiation. The hormones could be potentially used for AIDS or cancer patients.

24. Other Hormones- produced by tissues not glands
Leptin
Peptide hormone secreted by adipose tissue
Role: feedback control of appetite
Binds to neurons in CNS that are related to the control of appetite.
It was hoped that leptin could help control obesity in humans, but the results/stats are insignificantly inconclusive.

25. Other Hormones- produced by tissues not glands
Erythropoietin (EPO)
Peptide hormone produced by kidneys
Released in response to low oxygen levels
Stimulates the production and maturation of red blood cells
People who have anemia (common in kidney disease, cancer, or AIDS) may receive injections of EPO
Blood doping- Athletes use EPO to improve athletic performance by increasing oxygen carrying capacity of their red blood cells. This has more risks than benefits. Thicker blood= higher blood pressure= higher risk for heart attack or stroke

26. Other Hormones- produced by tissues not glands
Local Hormones- produced by cells- act on neighboring cells
Cytokines and Prostaglandins- potent chemical signals from within arachidonate cells (fatty acid)
In the uterus, this hormone causes muscles to contract- it is partly responsible for menstrual cramps and pain
Mediates the effect of pyrogens (chemicals that reset the temperature regulatory center of the brain). Aspirin works as a painkiller because it affects this hormone.
Prostaglandin therapy in still in experimentation because it affects several things
Some prostaglandins reduce gastric secretion and can be used to treat ulcers
Some lower blood pressure and have been used to treat hypertension
Some inhibit platelet congregation and have been used to treat thrombosis

27. IB Bio Standards just in case/for reference
6.5.7 State that the endocrine system consists of glands that release hormones that are transported in the blood.
6.5.8 State that homeostasis involves maintaining the internal environment between limits, including blood pH, carbon dioxide concentration, blood glucose concentration, body temperature and water balance.
6.5.9 Explain that homeostasis involves monitoring levels of variables and correcting changes in levels by negative feedback mechanisms.
Explain the control of blood glucose concentration, including the roles of glucagon, insulin and α and β cells in the pancreatic islets.

28. 6.5.12 Distinguish between type I and type II diabetes.
6.6.2 Outline the role of hormones in the menstrual cycle, including FSH (follicle stimulating hormone), LH (luteinizing hormone), estrogen and progesterone.
.6.3 Annotate a graph showing hormone levels in the menstrual cycle, illustrating the relationship between changes in hormone levels and ovulation, menstruation and thickening of the endometrium.
6.6.4 List three roles of testosterone in males.
for answers/ reference
Another set of standards w/ the answers to them w/more resources
POssible quiz Questions:

29. Puberty Ted Talk: https://www.youtube.com/watch?v=MBHvq7aw2Ok
Thyroid: metabolism-emma-Bryce
Stress: bergquist