1. The Great Communicator
Chapter 11
The Great Communicator

2. Functions of the Endocrine System
The endocrine system is composed of ductless glands that secrete chemical messengers called hormones into the bloodstream.
Endo- means within.
-crine means to secrete or separate.

3. Functions of the Endocrine System
Hormones enter the bloodstream and are carried throughout the body to affect a variety of tissues and organs.

4. Structures of the Endocrine System
The glands of the normal endocrine system:
one pituitary gland
one thyroid gland
four parathyroid glands
two adrenal glands
one pancreas
one thymus
one pineal gland
two gonads 4

5. The Pituitary Gland
The pituitary gland is located at the base of the brain just below the hypothalamus.
The hypothalamus secretes releasing and inhibiting factors that affect the release of substances from the pituitary gland.
The combining form for the pituitary gland is pituit/o.
The pituitary gland has two lobes: anterior and posterior.

6. Pituitary Gland Controls all other glands
Located within the sphenoid bone of the skull
Divided into 2 lobes
Anterior lobe
Posterior lobe

7. The Anterior Pituitary Gland
Secretions of the anterior pituitary gland:
thyroid stimulating hormone (TSH)
adrenocorticotropic hormone (ACTH)
follicle-stimulating hormone (FSH)
luteinizing hormone (LH)
interstitial cell-stimulating hormone (ICSH)
prolactin
growth hormone (GH)
melanocyte-stimulating hormone (MSH) 7

8. Anterior Lobe Growth Hormone (Somatropin)
Thyroid Stimulating Hormone (TSH)
Gonadotropic Hormones
Ovaries
Follicle stimulating hormone (estrogen)
Luteinizing Hormone : formation of corpus luteum
Testes
Follicle stimulating hormone (development of sperm cells)
Luteinizing Hormone : testosterones
Prolactin (mammary gland development)

9. Adrenocorticotropic Hormone (ACTH)
Adrenal glands
Production of corticosteriods
Melanocyte stimulating hormone (MSH)
melanin pigment in skin and hair
Involved in ability to undergo chameleonlike color changes

10. The Posterior Pituitary Gland
Secretions of the posterior pituitary gland:
antidiuretic hormone (ADH)
oxytocin 10

11. Posterior Lobe Antidiuretic hormone (ADH) Oxytocin
Limits development of large volume of urine by
reabsorbing water by kidneys
Oxytocin
Stimulates milk production and contraction of uterus
during parturition

12. The Thyroid Gland
The thyroid gland is a butterfly-shaped gland that secretes the following:
triiodothyronine (T3)
thyroxine (T4)
calcitonin
The combining forms for the thyroid gland are thyr/o and thyroid/o.

13. Thyroid Gland Regulates growth and metabolism
Over or under production of iodine
Calcitonin maintains balance of calcium
in the blood by decreasing
In birds causes molting and other behaviors linked to
Changes in daylight.

14. January 7, 2015
From memory -
List the names of the glands belonging to the
Endocrine System: 1. 2. 3. 4. 5. 6. 7. 8.

15. The Parathyroid Glands
The parathyroid glands are usually four glands located on the surface of the thyroid gland.
The parathyroid glands secrete parathormone.
The combining form for the parathyroid glands is parathyroid/o.

16. Parathyroid Gland “Near” thyroid gland / 2 on each side
Parathyroid Hormone (PTH)
Regulates calcium
Maintains balance of calcium in blood by
decreasing

17. The Adrenal Glands The adrenal cortex secretes
The adrenal glands are two glands located cranial to each kidney;
they consist of a cortex and a medulla.
Ad- means toward.
Ren/o means kidney.
The adrenal cortex secretes
mineralocorticoids
glucocorticoids
and androgens (sex hormones) .

18. Adrenal Glands The adrenal medulla secretes
epinephrine (adrenoline)
and norepinephrine
The combining forms for the adrenal glands
are adren/o and adrenal/o.

19. The Pancreas
The pancreas is a gland located near the proximal duodenum that has exocrine and endocrine functions.
The endocrine functions of the pancreas maintain blood glucose levels.
The pancreas secretes insulin and glucagon.
The combining form for the pancreas is pancreat/o.

20. Pancreas Insulin Glucagon Use and storage of carbohydrates (sugar)
Decrease blood glucose levels
Glucagon
Increase blood glucose levels

21. The Thymus
The thymus is a gland predominant in young animals located near midline in the cranioventral portion of the thoracic cavity.
The thymus secretes thymosin which is responsible for production of white blood cells (T- lymphocyte cells) / immunity
In adulthood becomes fatty piece of tissue

22. The Pineal Gland
The pineal gland is located near midline in the central portion of the brain and functions in maintaining circadian rhythm.
The pineal gland secretes melatonin.
Resemble pinecone
The combining form for the pineal gland is pineal/o.

23. The Gonads The gonads are glands that produce gametes (sex cells).
The gonads are the ovaries in females and the testes in males.
The combining form for the gonads is gonad/o.

24. The Ovaries The ovaries are the female gonads.
Secretions of the ovaries:
estrogen
progesterone . 24

25. The Testes The testes are the male gonads. Secretion of the testes:
testosterone 25

26. Hyperadrenocorticism
Over production of glucocorticoid (hormone)
Commonly called Cushings Disease
An opposite disease is Addison’s where there is a
deficiency
Signs:
Polydypsia
Polyuria
Body fat distribution

27. Pathological Conditions

28. Hyperthyroidism Common in aging cats
Excessive production of thyroid hormone
Can feel an enlarged thyroid gland
Can be treated with medication
Surgical removal of the thyroid gland

29. Signs of Hyperthyroidism
Weight loss (increased metabolism)
Polyuria
Polydipsia
Meowing
Aggression
Affection
(Behavior changes)

30. Diabetes Mellitus Insulin is hormone that transports blood
glucose to be stored (as glycogen)and used
for energy needs of cells
Pancreas doesn’t produce insulin, too much
glucose in blood
Results in low pH of blood (acid)
Ketoacidosis = low blood pH and ketones (which
are by products of fat metabolism)

31. Ketoacidosis is result of no production
of insulin = blood glucose (“sugar”)
Hypoglycemic is the opposite and is the
result of overdose of insulin!

32. Things to remember about diabetes
Signs of diabetes:
Often overweight
Middle aged – senior
Breed predisposition
Cats
Polydipsia
Polyuria
Sudden weight loss
cataracts

33. Things to remember Too much insulin can kill
Diabetes can be treated but not cured:
balancing between too much insulin and
too little insulin
difficult for owners to understand initially
treatment is lifetime
Too much insulin can kill
Too little can result in death also

34. Medical Terms for the Endocrine System
Additional terms for endocrine system tests, pathology, and procedures can be found in the text.
Review StudyWARE to make sure you understand these terms.