1. Endocrine System
UNIT 7

3. Endocrine System
Endocrine glands – secrete hormones into nearby tissues, diffuse into bloodstream (Ex. - thyroid, pituitary, adrenal, etc.)
Exocrine glands – secrete into tiny tubes or ducts (sweat, salivary, etc.)
Some organs (pancreas) are both endocrine and exocrine

4. Exocrine Gland - ducts

5. Hormones
Chemical secreted by a cell that has an effect on the functions of another cell
Very specific – affect only their target cell
Increase # of receptors – increase response
Effect can be brief or long-lasting
Antagonists – hormones that work against each other
Synergists – hormones that work together

6. Pituitary Gland (AKA Hypophysis)

7. Pituitary Gland Also known as Hypophysis Size of a pea
Attached to the brain by a stalk (infundibulum)
Rests in a bony depression of the sphenoid bone (sella turcica)
2 lobes
anterior lobe – 7 hormones
posterior lobe – 2 hormones

8. Anterior Lobe (adenohypophysis)
Prolactin (PRL) – inc. milk production and sustains it after birth
Adrenocorticotropic Hormone (ACTH) - Regulates hormone release from adrenal cortex (stress hormones)
Growth Hormone (GH) – stimulates body cells to grow and divide; inc. body’s ability to use fats and carbs for energy

9. GH Secretion OVERSECRETION during childhood [before puberty]
Leads to Gigantism
OVERSECRETION
after puberty leads to Acromegly.
UNDERSECRETION before puberty leads to Dwarfism.

17. Posterior Lobe (neurohypophysis)
Anti-Diuretic Hormone (ADH) - AKA Vasopressin
stim. DCT/Collecting Duct to reabsorb water,
results in inc. in blood volume and blood pressure, and decrease in urination.
Also a vasoconstrictor (for raising blood pressure).
Failure of this hormone - diabetes insipidus liters of diluted urine/day, inc. thirst.

18. Oxytocin (OT) - increase in uterine contractions in childbirth (works on positive fdbk loop)
Vasoconstriction – to reduce blood flow and bleeding after childbirth
Ejection of milk during breast-feeding
These two hormones differ chemically by only two amino acids
Both Vasoconstrictors !!

19. Adrenal Glands (Suprarenal Gl.)
Located superior to Kidneys
2 Parts with hormones

20. Adrenal Cortex (stim. by ACTH from ant. Pituitary)
Aldosterone – (a mineralcorticoid)
Kidney cells (DCT/Collecting Duct) to reabsorb Na+, increasing blood volume (too much, with a weakened blood vessel can burst) and blood pressure.
Released by renin-angiotensin pathway.

21. Cortisol – (a glucocorticoid)
promotes the use of sugar (convert glycogen  glucose in the liver), lipids, and proteins
typically in the morning and/or during times of stress.
If not used – it will be re-stored as fat.

22. Adrenal Medulla Epinephrine/Norepinephrine (catecholimines)
sympathomimetic – cause changes that mimic sympathetic response [fight or flight]
inc. in hrt rate, BP
diversion of blood to hrt, brain, skeletal muscles, away from digestive organs
bronchial dilation (opens airways)

23. Pancreas*
Located posterior to stomach
Both endocrine and exocrine*

24. Pancreas
Insulin
From the beta cells in the pancreatic islets (of Langerhans).
In response to elevated blood sugar – helps transport glucose into cells.
Glucagon
From alpha cells in the pancreatic islets.
In response to lowered blood sugar – stimulates cells to convert glycogen  glucose

25. Pancreas conditions Type I Diabetes Mellitus (juvenile-onset)
– no insulin production
Type II Diabetes Mellitus (adult-onset)
–decreased sensitivity to insulin
--Obesity but can be gotten rid of with diet

26. Thyroid Gland
Cervical region
Butterfly-shaped

27. Thyroid Gland T4 – Thyroxine - 80% of secretions
T3 (Triiodothyronine) – 20% of secretions (4-5x stronger than T4)
T4 – Thyroxine - 80% of secretions
- Both function to increase metabolism, support growth and dev’t
- Decrease in these hormones leads to fatigue and weight gain 

28. Iodine needed in the diet to make these two hormones
*Iodine needed in the diet to make these two hormones. Not enough - can lead to overactivity, and swelling of the gland. Known as a goiter.

33. Thyroid Gland
Calcitonin – serves to increase storage of calcium in the bones by removing it from the blood
- lowers blood calcium levels

34. Parathyroid Gland
Located posterior to thyroid

35. Parathyroid Parathyroid Hormone (Parathormone)
– opposite effect as calcitonin [antag]
– increases blood calcium levels by encouraging removal of calcium from the bones