ENDOCRINE SYSTEM

August 17, 2008 at 4:39 am Leave a comment

ENDOCRINE SYSTEM

TYPES:
1. EXOCRINE – glands which have ducts or channels which carries their products to the site where they take effect.
2. ENDOCRINE – they have no ducts / channels but instead they secrete their products directly to the blood stream.

Hormones – products of the endocrine glands
– chemical compounds that may either be steroids or protein in nature
– they are produced from the raw materials within the cells and are secreted into the blood stream.

2 GENERAL FUNCTIONS OF HORMONES
1. it will maintain homeostasis (equilibrium/balance)
2. stimulate changes within the cell

target cell/organ – groups of cells/organs that respond to the effects of hormones
hormone receptors –

adenylate cyclase – once activated, it turns ATP into AMP (adenosine monophospahate)

I. PITUITARY GLAND / HYPOPHYSIS
– underneath the hypothalamus (midbrain)
– master gland because it controls almost of the endocrine gland

HORMONES SECRETED BY THE ANTERIOR PITUITARY GLAND
1. TSH (thyroid stimulating hormone)
2. ACTH (adenocorticotropic hormone)
3. FSH (follicle stimulating hormone) – growth & development of follicles
4. GH (growth hormone)
5. LH (leuteinizing hormone)
6. PROLACTIN –responsible for milk production

HORMONE SECRETED BY THE POSTERIOR PITUITARY GLAND
1. OXYTOCIN – contraction of the uterus
2. ADH (anti-diuretic hormone) / vasopressin –

DISORDERS OF THE PITUITARY GLAND
1. GIANTISM – oversecretion of the growth hormone
ACROMEGALY – enlargement of extremities
2. DWARFISM – undersecretion of the growth hormone

II. THYROID GLAND
– soft-brownish red organ shape like a butterfly or a letter H
– found in between the larynx and the trachea

isthmus – connects the 2 lobes of thyroid gland
thyroxine – controls metabolism

DISORDERS
1. HYPERTHYROIDISM – oversecretion of TSH
– there is weigth loss
2. HYPOTHYROIDISM – enlargement of thyroid gland

2 TYPES
a. CRETINISM – in infants, causes mental retardation
b. MYXEDEMA – in adults, causes mental retardation

III. PARATHYROID GLAND
– embedded within the thyroid gland
– pea-shaped organ

PARATHORMONE –

IV. ADRENAL GLAND
– found above each kidneys
1. adrenal cortex
a. glucocorticoids
b. mineralocorticoids
c. sex hormones
2. adrenal medulla/epinephrines
DISORDERS
1. ADDISON’S DISEASE – underactivity of adrenal cortex
2. CUSHING DISEASE –
3. ANDROGENITAL SYNDROME –

Entry filed under: Biology. Tags: .

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