胰臟，或者應該叫“胰腺”——因為它是腺體嘛——位於人體左上腹的最深處，前面是胃，後面是錯綜複雜的血管和神經組織，是個混合性分泌腺體，由外分泌腺體和內分泌腺體兩部分組成。所以胰腺主要有外分泌和內分泌兩大功能。

胰臟的外分泌主要成分是胰液，內含鹼性的碳酸氫鹽和各種消化酶，其功能是中和胃酸，消化糖、蛋白質和脂肪。

胰臟的內分泌主要成分是胰島素、胰高血糖素，其次是生長激素釋放抑制激素、腸血管活性肽、胃泌素等。

聽說過肥皂的另一個大名“胰子”吧？，先人早就知道動物的胰臟可去油汙，用宰殺動物胰臟在手或衣服上搓刷，油漬即無影無蹤。這是因為胰腺有強烈的消化酶——胰澱粉酶、胰蛋白酶和脂肪酶，它可將肉食完全溶化，消化酶所到之處組織全部被消化。

胰液透過胰管進入腸道消化食物，若胰管賭塞，消化酶外溢，周圍的一切均被破壞，人體組織會被當做食物消化，這就是可怕的“胰腺炎”，重型胰腺炎死亡率高達17-30%。

胰腺除分泌消化酶外，還分泌胰島素。散佈在胰腺各處的胰島，是胰島細胞組成的簇團，分泌胰島素。若胰島減少，胰島素分泌不足，就發生糖尿病。

胰島素能促進肝糖原和肌糖原的合成，此作用主要透過提高肝臟和肌肉中糖原合成酶的活性而完成；能促進葡苟糖進入肌肉和脂肪組織細胞內；啟用葡萄糖激酶，生成6—磷酸葡萄糖；抑制糖異生。

胰島分泌的胰島素非常奇怪，它並不從胰管進入腸道而是直接進入血液。長期飲酒或膽道炎症會破壞胰腺和胰島，糖尿病明顯增高。

胰腺功能下降，首要問題是消化不良，吃什麼原樣排洩什麼，食物不消化，導致營養不良。

炎症會使胰島細胞萎縮，胰島素分泌不足，糖尿病隨之而來，血糖遊離於身體每個角落，卻無法讓組織細胞利用，血管內膜下出現斑塊，血管硬化，免疫功能低下，冠心病、高血壓、白內障、組織感染，噩夢從此開始。

愛護胰腺非常重要。尤其是嗜煙酗酒者，罹患胰腺疾病的機率非常高。胰腺癌是實體腫瘤中最兇險、最難治癒的“癌中之王”，5年存活率幾乎為0。

胰臟分兩個塊：胰腺和胰島。

胰腺分泌胰液，包含多種消化酶。

胰島的阿爾法細胞分泌胰高血糖素，促進肝糖原分解，使血壓升高。

貝塔細胞分泌胰島素，促進肝糖原的合成，使血壓降低。

The pancreas is an organ that lies beneath the stomach. It"s nestled in a loop formed by the first portion of the small intestine. It"s a dual-purpose organ, having both exocrine and endocrine functions.

As an exocrine gland, it produces enzymes and sodium bicarbonate essential for the digestion of foodstuffs in the small intestine. They flow into the small intestine by a duct called pancreatic duct.

Its endocrine function is fulfilled by special cells that produce hormones such as insulin and glucagon that help regulate blood glucose level, thus assisting in maintaining homeostasis.

The digestive enzymes of the pancreas flow through the large pancreatic duct into the duodenum. Each day, approximately 1200~1500 ml of pancreatic juice is produced and released into the small intestine. This liquid is composed of water, sodium bicarbonate, and several digestive enzymes as follows:

Trypsin: cleaves peptide bonds of polypeptides and proteins.

Chymotrypsin: cleaves peptide bonds of polypeptides and proteins.

Carboxypeptidase: cleaves peptide bonds on carboxyl end of polypeptides.

Amylase: breaks starch molecules into smaller units (i.e. maltose).

Phospholipase: cleaves fatty acids from phosphoglycerides to form monoglycerides.

Lipase: cleaves 2 fatty acids from triglycerides

Ribonuclease: breaks RNA into smaller nucleotide chains.

Deoxyribonuclease: breaks DNA into smaller nucleotide chains.

Sodium bicarbonate neutralizes the acidic chyme released by the stomach and thus protects the small intestine from stomach acid. It also gives the pancreatic juice a pH of about 8, creating an environment optimal for the function of the pancreatic enzymes.

The pancreatic enzymes released into the small intestine act on the large food molecules, i.e. proteins, starches, etc. As a result of pancreatic enzymatic activity, fats, proteins, and carbohydrates are broken down into smaller molecules.

The pancreas secretes its enzymes in an inactive form. This protects the gland from self-destruction. Trypsinogen, for example, is the inactive form of the protein-digesting enzyme trypsin. Produced by the pancreas, trypsinogen is activated by a substance on the epithelial lining of the small intestine. Trypsin, in turn, activates other digestive enzymes.