請問endocrine 同 exocrine 既分別?

Exocrine gland
















Exocrine gland




圖片參考：http://upload.wikimedia.org/wikipedia/commons/thumb/a/a1/Gray1026.png/250px-Gray1026.png


Human submaxillary gland. At the right is a group of mucous alveoli, at the left a group of serous alveoli.
Exocrine glands are glands that secrete their products into ducts (duct glands). They are the counterparts to endocrine glands, which secrete their products directly into the bloodstream (ductless glands).








Examples
Typical exocrine glands include sweat glands, salivary glands, mammary glands, and many glands of the digestive system.

Types
There are multiple ways of classifying exocrine glands:

Structure
Exocrine glands contain a glandular portion and a duct portion, the structures of which can be used to classify the gland.

The duct portion may be branched (called compound) or unbranched (called simple).
The glandular portion may be tubular, acinar, or may be a mix of the two (called tubuloacinar). If the glandular portion branches, then the gland is called a branched gland.

Method of secretion
Exocrine glands are named apocrine, holocrine gland, or merocrine gland based on how their product is secreted.

Apocrine glands - a portion of the plasma membrane buds off the cell, containing the secretion. Apocrine gland is often used to refer to the apocrine sweat glands.
Holocrine glands - the entire cell disintegrates to secrete its substance.
Merocrine glands - cells secrete their substances by exocytosis. Also called "eccrine."
Endocrine system




圖片參考：http://upload.wikimedia.org/wikipedia/en/d/da/Illu_endocrine_system.png


Major endocrine glands. (Male left, female on the right.) 1. Pineal gland 2. Pituitary gland 3. Thyroid gland 4. Thymus 5. Adrenal gland 6. Pancreas 7. Ovary 8. Testes
The endocrine system is an integrated system of organs which involve the release of extracellular signaling molecules known as hormones. The endocrine system is instrumental in regulating metabolism, growth and development, tissue function, and plays a part also in mood. The field of medicine that deals with disorders of endocrine glands is endocrinology, a branch of the wider field of internal medicine.



Function of the Endocrine System
The endocrine system is an information signaling system much like the nervous system. However, the nervous system uses nerves to conduct information, whereas the endocrine system uses blood vessels as information channels. Glands located in many regions of the body release into the bloodstream specific chemical messengers called hormones, which regulate the many and varied functions of an organism. The typical endocrine organ is a ductless gland that secretes chemical mediators directly into local blood vessels which circulate within the body via the bloodstream. These hormones travel to distant organs to regulate the target organ's function. This is classical endocrine signalling. Other signalling can target the same cell (known as Autocrine signalling) or nearby cells (known as Paracrine signalling). Hormones are also instrumental in regulating mood, growth and development, tissue function, and metabolism, as well as sending messages and acting on them.
Ductless : secretion not via duct