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ENDOCRINE SYSTEM

SAKINA

DEPARTEMEN ANATOMI-

HISTOLOGI FKUA 12/6/2013

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ENDOCRINE SYSTEM

Interacts with the nervous system to

maintain homeostasis.

Responsible for :

1. The regulation of fluid and electrolyte

balance,

2. Cell and tissue metabolism,

3. Growth and development,

4. Reproductive functions.

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ENDOCRINE SYSTEM

Ductless glands

Secrete hormones

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ENDOCRINE SYSTEM

Hormones are messenger molecules

Circulate in the blood

Act on distant target cells

Target cells respond to the hormones for

which they have receptors

The effects are dependent on the

programmed response of the target cells

Hormones are just molecular triggers

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Basic categories of hormones

Amino acid based: modified amino acids

(or amines), peptides (short chains of

amino acids), and proteins (long chains of

amino acids)

Steroids: lipid molecules derived from

cholesterol

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MECHANISM OF HORMON

RELEASE

Turn on system :

1.Response to variations in the concentrations of specific substances in the body fluids. Ex : PTH

2.Hormonal instructions from other endocrine organs. Ex : Thyroid

3.Response to neural stimulation. Ex : adrenalin

Turn off system :negative feedback system

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RECEPTORS REGULATION

UP regulation

DOWN regulation

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Endocrine Organs

Purely endocrine organs Pituitary gland

Pineal gland

Thyroid gland

Parathyroid glands

Adrenal: 2 glands Cortex

Medulla

Endocrine cells in other organs Pancreas

Thymus

Gonads

Hypothalamus 12/6/2013

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Two divisions:

Anterior pituitary (adenohypophysis)

Posterior pituitary (neurohypophysis)

Pituitary secretes 9 hormones The Pituitary

1. TSH

2. ACTH

3. FSH

4. LH

5. GH

6. PRL

7. MSH

8. ADH (antidiuretic hormone), or vasopressin

9. Oxytocin

_________________________________________________________________

The first four are tropic

hormones, they regulate the

function of other hormones

________

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What the letters stand for

TSH: thyroid-stimulating hormone

ACTH: adrenocorticotropic hormone

FSH: follicle-stimulating hormone

LH: luteinizing hormone

GH: growth hormone

PRL: prolactin

MSH: melanocyte-stimulating hormone

ADH: antidiuretic hormone

Oxytocin

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DWARFISME

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Posterior Pituitary (stores & releases hormones produced by hypothalamus)

Antidiuretic hormone (ADH) targets kidneys stimulates reabsorption of

water

targets blood vessels regulates blood

pressure

Hyposecretion : diabetes insipidus

Hypersecretion : syndrome of inappropriate

ADH secretion

Oxytocin targets uterus stimulates contraction

targets mammary glands stimulates

release of milk when baby nurses

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Releasing hormones (releasing factors) of

hypothalamus

TRH (thyroid releasing hormone) -----turns on* TSH

CRH (corticotropin releasing hormone) -----turns on

ACTH

GnRH (gonadotropin releasing hormone) ---turns on FSH

and LH

PRF (prolactin releasing hormone) -----turns on PRL

GHRH (growth hormone releasing hormone) ----turns on

GH

Inhibiting hormones of hypothalmus

PIF (prolactin inhibiting factor) -----turns off PRL

GH (growth hormone) inhibiting hormone ---turns off GH

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THYROID GLAND

Consists of two lobes

Located on either side

of trachea

Isthmus connects the

two lobes

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THYROID GLAND

Thyroxine (T4), triiodothyroxine (T3)

Target cells all cells of body (increase

metabolic rate of carbohydrates,lipids,proteins)

Calcitonin : help lower blood calcium levels, acts

mostly during childhood

Hypersecretion : hyperthyroidism (ex. Graves

disease)

Hyposecretion : hypothyroidism ( kretinism,

mixedema)

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THYROID GLAND

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CALCITONIN VERSUS PTH

Text or image

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The Parathyroid Glands

Most people have four

On posterior surface of

thyroid gland

(sometimes embedded)

Action ?

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PARATHYROID GLAND

Hyperparathyroid : causes metastatic

calcification

Hypoparathyroid : causes convulsions

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Adrenal (suprarenal) glands (suprarenal means on top of the kidney)

Each is really two endocrine glands Adrenal cortex (outer)

Adrenal medulla (inner)

Unrelated chemicals but all help with extreme situations

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Adrenal Gland

Adrenal cortex

Secretes lipid-based steroid hormones, called

corticosteroids cortico as in cortex

MINERALOCORTICOIDS

Aldosterone is the main one

GLUCOCORTICOIDS

Cortisol (hydrocortisone) is the main one

GONADOCORTICOIDS

- small amounts

Adrenal medulla

Secretes epinephrine and norepinephrine

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The Pineal Gland

At the end of a short stalk on the roof of the diencephalon

Pinealocytes with dense calcium particles

Can be seen on x-ray (because of Ca++)

Melatonin helps regulate the circadium rhythm

The biological clock of the diurnal (night/day) rhythm

Complicated feedback via retinas visual input

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Pituitary__________ (hypophysis)

Hypothalamus___________

Hypothalamus__ Anterior pituitary__

(adenohypophysis)

_____________Posterior pituitary

(neurohypophysis)

Learn the 3 endocrine organs on this slide:

Hypothalamus

Pituitary (hyophysis)

Pineal

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Pancreas

Classified as exocrine & endocrine gland.

Endocrine

portion (islets

of Langerhans)

secretes

hormones.

Exocrine portion secretes digestive enzymes.

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Pancreatic islet

endocrine cells

Alpha cells: secrete glucagon

raises blood sugar

mostly in periphery

Beta cells: secrete insulin

lowers blood sugar

central part (are more abundant)

Also rare Delta cells:secrete

somatostatin

inhibits glucagon

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Ovaries

Estrogen

targets most cells develops & maintains sexual

characteristics in females; stimulates growth of

uterine lining

Progesterone

targets uterus stimulates growth of uterine lining;

maintains pregnancy

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Testes Testosterone

targets most cells develops & maintains sexual

characteristics in males; promotes sperm formation

Inhibin

targets anterior pituitary inhibits FSH release

(decreases sperm formation)

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THYMUS

Located deep to the sternum in the thorax

Diminishes in size troughout adulthood

Essential for the normal development of T

Lymphocytes

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The placenta secretes steroid and protein hormones Estrogens, progesterone

CRH

HCG

The kidneys Juxtaglomerular cells secrete renin

Renin indirectly signals adrenal cortex to secrete aldosterone

Erythropoietin: signals bone marrow to increase RBC production

The skin Modified cholesterol with uv exposure becomes Vitamin D

precursor

Vitamin D necessary for calcium metabolism: signals intestine to absorb CA++

Endocrine cells in various organs

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TERIMA KASIH

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