1. The Endocrine System
Eden Area ROP
Medical Careers

2. Endocrine Glands Endocrine glands:
Ductless glands; secrete directly into blood
Widely distributed throughout the body
Secrete hormones: chemical messengers that produce changes in the body
Regulate growth/development
Regulate metabolism
Stimulate other glands
Exocrine glands: secrete substances into ducts (EX: sweat gland, sebaceous (oil) glands) NOT part of the endocrine system

3. Hormones
Hormones that are released from the endocrine glands have a target gland in which the hormone has an affect on.

4. Mechanisms that control hormone secretion
Negative feedback: information about the hormone or its effects is fed back to the gland that secretes it
2. Biorhythms: rhythmic alteration in a hormone’s rate of secretion
Circadian rhythm: 24-hour rhythm
3. Central nervous system helps control secretion of hormones in two ways:
Activation of hypothalamus
Stimulation of sympathetic nervous system

5. The Pituitary Gland
Pituitary gland: pea-sized gland located in the center of the brain and attached to hypothalamus
Two main parts:
Anterior pituitary gland
Posterior pituitary gland

6. The Pituitary Gland (cont’d.)
Hypothalamus: controls secretions of the anterior pituitary gland
Hypothalamic-hypophyseal portal system: network of capillaries that connects the hypothalamus with the anterior pituitary gland

7. Pituitary Gland Hormones
AKA the “Master gland” because:
Secretes hormones that control other glands and affect many organ systems
Hormones of the pituitary gland:
Prolactin: promotes breast development/milk production after childbirth
Growth hormone (GH): essential for the growth/development of body’s tissues, effects length of long bones
Thyroid-stimulating hormone (TSH): stimulates thyroid gland to secrete two thyroid hormones
Follicle-stimulating hormone (FSH): stimulates ovaries (female), production of sperm (male)
Luteinizing Hormone (LH): stimulates ovaries (production of progesterone) and stimulates testes (production of testosterone)

8. Pituitary Gland Hormones
Hormones of the pituitary gland (cont.):
Melanocyte-stimulating hormone (MSH):increases the amount of pigment in the skin
Oxytocin: stimulates uterine contractions
Anti-diuretic Hormone: Retains fluid in the body

9. Growth Hormone Conditions
Dwarfism: insufficient production during childhood
Gigantism: Overproduction in childhood
Acromegaly: Overproduction during adulthood

10. Thyroid Gland Largest endocrine gland
Located in anterior neck on front and sides of trachea

11. Thyroid Gland (cont’d.)
Thyroid hormones: function to regulate all phases of metabolism, necessary for:
Proper functioning of all other hormones
Normal maturation of the nervous system
Normal growth and development
Hormones secreted:
Triiodothyronine (T3) & Tetraidothyronine (T4): regulates metabolism
Thyrocalcitonin: decreases blood calcium levels (increases calcium storage in bones)

12. Thyroid Gland (cont’d.)
Hypothyroidism: thyroid hormone deficiency resulting in a slowed-down metabolic state
Hyperthyroidism: excess of thyroid hormones produces a sped-up metabolic state

13. Parathyroid Glands Parathyroid glands:
Lie along the posterior surface of the thyroid gland
Secrete parathyroid hormone (PTH), which increases blood calcium levels (decreases calcium in the bones)

14. Parathyroid Glands (cont’d.)
Hypocalcemia: absence of sufficient calcium causes carpal spasm
Hypercalcemia: hyperparathyroidism develops in response to a tumor in the parathyroid gland (causes bone pain and kidney stones)

15. Adrenal Glands Located above kidneys Two regions:
Adrenal medulla: inner region of the adrenal gland, excretes catecholamines
Adrenal cortex: outer region of the adrenal gland, secretes steroids

16. Adrenal Glands (cont’d.)
Catecholamines:
Epinephrine (Adrenaline): stimulates “fight or flight” response
Steroids: (regulate sugar, salt, sex)
Cortisol: (sugar) helps maintain blood glucose between meals, “stress hormone”
Aldosterone: (salt) regulates blood volume and sodium and potassium levels
Sex hormones (small amounts) secondary sex characteristics

17. Pancreas Long, slender organ that lies across the upper abdomen
Functions: exocrine gland and endocrine gland because it secretes hormones (insulin/glucagon) directly into bloodstream. Exocrine function- secretes pancreatic juices that aide in digestion into the digestive system (through a duct)
Hormones:
Insulin: decreases blood glucose levels
Glucagon: increases blood glucose levels

18. Pancreas (cont’d.)
Diabetes mellitus: insulin deficiency or ineffectiveness
Signs:
Hyperglycemia
Glucosuria
Polyuria
Polydypsia
Polyphagia

19. Diabetes Mellitus Type 1: Insulin Dependent Diabetes Mellitus
AKA Juvenile Diabetes
Not enough insulin is being produced
Type 2: Non-Insulin Dependent Diabetes Mellitus
AKA Adult onset Diabetes Mellitus
Insulin is produced, but the body is not using it properly
Gestational Diabetes Mellitus (GDM): occurs in pregnancy

20. Gonads (sex glands) Male: testes (located in scrotum)
Testosterone:
produce sperm
Male primary and secondary sex characteristics
Female: ovaries (located within the female pelvic cavity)
Estrogen
Produce ova (eggs)
Female primary and secondary sex characteristics
Progesterone
Affects uterine lining

21. Thymus Gland Lies in the thoracic cavity behind the sternum Hormones:
Thymosins: stimulates the development and maturation of lymphocytes (T-cells)

22. Pineal Gland (Pineal Body) (“biological clock”)
Cone-shaped gland located close to the thalamus in the brain (behind pituitary gland)
Hormone: melatonin
Controls biorhythms
Sleep-wake cycle
Delays puberty until appropriate time

23. The Endocrine glands

24. Abbreviations Look up definitions!
GDM
ADH
FBS
IDDM
NIDDM
GTT (not gtt) GH
TSH