1. The Endocrine System
Chapter 11

2. Gland types Endocrine glands Exocrine glands
Send secretion DIRECTLY into blood stream
Ex: pituitary, thyroid, pancreas
Exocrine glands
Send secretion into a DUCT that carries secretion to its destination
Ex: salivary, lacrimal, pancreas

3. Terminology
Endocrinology: the study of the structure, function, and disorders of the endocrine system
Hormone: chemicals secreted by endocrine glands
Hypersecretion: over secretion (too much) of a hormone
Hyposecretion: under secretion (not enough) of a hormone
Target cells: specific body areas that are affected by circulating hormones (traveling in blood stream)
Local hormones: act on local or nearby cells without traveling through blood; example: prostaglandins (PGs)
Distress: bad stress that is negative and harmful
Eustress: good stress that is positive and productive

4. Hormone function Control growth & development
Govern reproductive system operation
Regulate body function
Secretion, metabolism, internal clock

5. Remember feedback loops?
Endocrine glands & hormones work by way of feedback loops
Negative Feedback Loops: will reverse action
Hormone levels are too high so secretion DECREASES/STOPS
Most are this type
Positive Feedback Loops: will enhance action
Hormone levels are too low so secretion INCREASES/BEGINS

6. 10 Endocrine glands (see p. 291, fig. 11-2)
Hypothalamus (1)
Pituitary (1)
Pineal (1)
Thymus (1)
Thyroid (1)
Parathyroids (4)
Adrenals (2)
Pancreas (1)
Ovaries (2)
Testes (2)

7. Hypothalamus Major link with nervous system Location/Cavity
Cranial cavity; below thalamus
Hormones (2) & function
Releasing Factors (RF’s): stimulate production of hormones
Inhibiting Factors (IF’s): ceases production of hormones
These RF’s and IF’s stimulate the pituitary gland

8. Pituitary Gland = Hypophysis
Location/Cavity
Cranial cavity; posterior to optic chiasm
2 lobes:
Anterior lobe (larger)
Secretes 7 hormones
Posterior lobe (smaller)
Secretes 2 hormones

10. Anterior Pituitary Hormones (7) & function
* Denotes tropic hormones; they control other endocrine glands.
Hormones (7) & function
Prolactin (PRL)  milk production
Melanocyte Stimulating Hormone (MSH)  melanin production
*Luteinizing hormone (LH)*  sex hormone production from gonads
*Follicle stimulating hormone (FSH)*  gamete production from gonads
*Adrenocorticotropic hormone (ACTH)*  adrenal cortex
Human growth hormone (hGH)  mitotic rates
*Thyroid Stimulating hormone (TSH)*  thyroid hormones

11. Posterior Pituitary Hormones (2) & function
Oxytocin (OT) Promotes uterine contractions
Synthetic OT = pitocin
Anti-diuretic hormone (ADH)  Regulates water levels in blood
Often called “water retaining” hormone
Alcohol consumption interrupts its secretion

13. Pituitary Disorders Hypersecretion Hyposecretion
hGH  gigantism (adolescence)
hGH  acromegaly (adulthood)
Hyposecretion
hGH  dwarfism
ADH  diabetes insipidus

15. Pineal Gland Small, pine-cone shaped Location/Cavity
Cranial cavity; inferior to corpus callosum
Hormone (1) & function
Melatonin  sleep/wake cycles; menopause (females)

16. Thymus Gland Location/Cavity Hormone (1) & function
Mediastinum; posterior
to sternum, between lungs
Hormone (1) & function
Thymosin  immunity
Adversely affected by stress, so immunity is often lowered as a result

17. Thyroid Gland Location/Cavity Hormones (3) & function
Neck; inferior to larynx
Hormones (3) & function
Triiodothyronine (T3)  energy & metabolism
Thyroxine (T4)  energy & metabolism
Calcitonin  decreases blood calcium levels
Iodine is needed in the diet in proper amounts to maintain proper T3 & T4 levels. If iodine is inadequate, a goiter can develop.

18. Thyroid Disorders Hypersecretion Hyposecretion
T3 & T4 = Grave’s disease
Incredibly thin; bulging eyes
Hyposecretion
T3 & T4 = cretinism (infancy)
T3 & T4 = myxedema (adulthood)
Overweight; fluid retention

20. Parathyroid Glands Smallest of all endocrine glands Location/Cavity
In neck; one on each lobe of thyroid gland
Hormone (1) & function
Parathyroid hormone (PTH)  increases blood calcium levels
Antagonist to calcitonin from thyroid

21. Pancreas Islets of Langerhans are the endocrine portion
Also serves in digestion (exocrine)
Location/Cavity
Abdominal; connected by mesentery to stomach & duodenum
Hormones (2) & function
Glucagon  increases blood sugar
Insulin  decreases blood sugar
Glucagon & insulin are antagonists to each other.

23. Pancreas Disorders Hypersecretion Hyposecretion
Glucagon  hyperglycemia (high blood sugar) = diabetes mellitus
Insulin  hypoglycemia (low blood sugar)
Hyposecretion
Glucagon  hypoglycemia (low blood sugar)
Insulin  hyperglycemia (high blood sugar)

25. Adrenal Glands Location/Cavity Divided into 2 regions
Abdominal; one sits on top of each kidney
Divided into 2 regions
Outer region = adrenal cortex
Subdivided into outer, middle, & inner zones
Inner region = adrenal medulla

26. Adrenal Gland (continued)
Hormone groups (5) & function
Adrenal medulla
Epinephrine (adrenalin) & norepinephrine (noradrenalin)  Fight-or-flight
Adrenal cortex
Outer (zona glomerulosa)
Mineralocorticoids such as aldosterone
Middle (zona fasciculata)
Glucocorticoids such as cortisol
Inner (zona reticularis)
Sex hormones such as androgens

27. Adrenal Disorders Hypersecretion Hyposecretion
Cortisol  Cushing’s disease
Fat displacement = buffalo hump; moon-shaped face
Hyposecretion
Cortisol  Addison’s disease
frail

29. Ovaries Female gonad Location/Cavity Hormones (2) & function
Pelvic; held in place by ligaments
Hormones (2) & function
Estrogen  female secondary sex characteristics
Progesterone  pregnancy

30. Testes Male gonad Location/Cavity Hormone (1) & function
Not in a cavity for temperature regulation
Hormone (1) & function
Testosterone  male secondary sex characteristics; libido

31. Hormone classes Lipid soluble Water soluble Dissolve in lipids
3 examples:
Steroid hormones
Cortisol, estrogen, progesterone
Thyroid hormones
T3 & T4
Nitric oxide
Gaseous neurotransmitter
Water soluble
Dissolve in water
4 examples:
Amine hormones
Epinephrine, norepinephrine, melatonin
Peptide hormones
ADH & OT
Protein hormones
hGH, insulin
Eicosanoid hormones
PGs & Leukotrienes

32. You MUST know… Location of the glands Hormone names
Hormone abbreviations (if applicable)
Hormone function
Disorders
*You will need to spend some time with this information. Make flash cards, flow charts, graphic organizers, etc. to help organize the information.