ENDOCRINE SYSTEM

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 –

NUTRITION

NUTRITION

Ø Process by which organism obtains food
Ø Main life sustaining process of living thing organisms

DIVERSITY OF ANIMAL NUTRITION
1. AUTOTROPHS – organism that produce their own food
Eg. photosynthetic plants, photosynthetic bacteria (euglena)

2. HETEROTROPHS
- cannot produce their own food but rather they depend on autotrophs or other animals for food
- All animals are classified in this category

a. HOLOZOIC – animals that take their food in a solid or non-diffusable form

b. PARASITES – depend their food on the hosts

REASONS WHY LIVING ORGANISM NEED ENERGY

1. disassembly and repair of tissue components

2. muscular and neural activities

3. metabolic activities

4. maintenance of molecular structure

FACTORS-AFFECTING THE AMOUNT OF ENERGY NEEDED BY AN ORGANISM

1. no. of cells

2. the rate of metabolic / cellular activities

FOOD

– is utilized by organisms as energy source or raw material for the synthesize of its own biological molecules

- any substance when absorbed into the body, yields or produces energy

- these are substances that provide materials for growth, maintenance and repair of the body tissue

calorie – amount of energy needed to raise 1 gram of water to 1º C

CONSTITUENTS OF FOOD

1. carbohydrates – in plants, stored in the form of starch

- among animals, usually stored in the form of glycogen

- main source of energy in the human body

- 4 cal/g

2. protein

Functions

1. forms most important constituents of the protoplasm
2. build up and repair of tissues
3. provides osmotic pressure

3. fats

- 9 kcal/g

Functions

1. serves as compact fuel molecules
2. serves as food reserves
3. thermal insulators
4. pr of hormones

4. vitamins – organic compounds occurring in natural food which are required in minute amounts for growth, maintenance of life and reproduction

A. fat-soluble vitamins – attach/combined with fat to be used up by the body