System -- 系統

When a collection of organs that work together to perform specific tasks, they form a body system. The human body can be distinguished into 10 systems, and each of them is essential for life.

當一些器官結集起來共同執行某些特殊任務的時候，就構成了人體的系統。人體可分為十個系統，各系統對維持生命都起著一定的作用。

The skeletal system consists of 206 bones. Its functions include:

骨骼系統由 206 塊骨頭組成。其功用包括：

Strengthen and support the body.

強化及支撐身體。

Protect important internal organs.

保護體內重要器官。

Provide attachments and levers for muscular contractions.

在運動中為肌肉提供附著點和槓桿。

Produce blood cells.

製造血球。

Site to storage and liberate minerals (e.g., calcium, phosphate, etc.).

礦物質（如鈣、磷等）儲存及釋放的場所。

The muscular system contains three different kinds of muscle, which vary in shapes and functions.

肌肉系統由三種不同形態和功能的肌肉組成。

Skeletal muscles are attached to the skeleton, and can be moved according to the mind (i.e., voluntary).

骨骼肌附著在骨骼上，能夠隨著意志活動。

Smooth muscles is found on the wall of hollow organs inside the body, and cannot be controlled by the mind (i.e., involuntary).

平滑肌構成體內器官的內層，不受意志操縱。

Cardiac muscles can only be found in the heart. Its strong and powerful contractions are also involuntary.

心臟肌只能在心臟找到，其強而有力的運動也是不受意志的控制。

Functions of the muscular system include:

肌肉系統的功用包括：

Constitute different kinds of body movements through muscular contractions (e.g. heart beat and breathing).

藉著肌肉收縮構成人體的各種活動（包括心跳和呼吸）。

Maintain posture, stabilize joints, and produce energy.

保持姿勢、固定關節及產生能量。

The nervous system is composed of the brain, spinal cord, and millions of nerve cells (i.e., neurons), which constitute a huge and complicated network. The major function of the nervous system is to pass information and nerve impulses from one part of the body to another.

神經系統由腦部、脊髓和數以百萬計的神經細胞（神經元）組成，並且構成了一個龐大而複雜的網絡。神經系統的主要功用是把訊息及神經衝動從身體的某處傳送至另一處。

The respiratory system consists of the lungs and the many air tracts of different sizes. Cells and tissues inside the human body must be continuously supplied with oxygen to produce energy for survival. The main function of the respiratory system is to provide passages and room for gaseous exchange.

呼吸系統由肺及各大小不同的氣管組成。人體內的細胞和組織，必須不斷有氧氣的補給才能夠產生能量和生存。呼吸系統的主要功用是提供空氣到肺的通路及氣體交換的場所。

The circulatory system is composed of the heart and a complicated network of blood vessels. Its main function is to transport nutrients and oxygen to the body tissues, and remove metabolic wastes from the cells at the same time.

循環系統由心臟和複雜的血管網絡構成，其主要功用是負責把養分和氧氣輸送至體內各組織，並同時把代謝後的廢物從細胞帶走。

The lymphatic system is made up of a network of lymph vessels that runs along the veins and arteries. It is a system to drain excess fluid from the spaces between cells. Functions of the lymphatic system include:

淋巴系統是由一組與靜脈及動脈平行的盲管所組成的網絡，是一套排除細胞間多餘體液的系統。淋巴系統的功用包括：

Drain excess fluid from the spaces between cells (i.e., lymph) back to the bloodstream.

把滯留在組織間多餘的體液（淋巴液）送回血流。

The lymph node along the lymph vessels contains cells that can destroy bacteria, and helps the immune response.

淋巴管的淋巴結有細胞可清除細菌，及幫助免疫反應。

The digestive system contains the esophagus and certain organs responsible for digestion (e.g., stomach, intestines, liver, and gall bladder). It main function is to break down food into smaller substances for better absorption.

消化系統由食道和一些負責消化的器官，如胃、腸、肝、膽等組成，其主要功用是把食物分解成較細小及容易被吸收的物質。

The urinary system is made up of two horsebean-shaped kidneys, two ureters, urinary bladder, and the urethra. Major functions of the urinary system include:

泌尿系統由兩個蠶豆形的腎臟、輸尿管、膀胱和尿道組成。泌尿系統的主要功用包括：

Discharge metabolic wastes outside the body through urination.

把代謝的廢物從尿液排出體外。

Maintain internal balance of water and salt .

維持體內水及鹽分的平衡。

Adjust pH of blood.

調節血液的酸鹼平衡。

The endocrine system is made up of special glands called the endocrine glands. Its major functions is to secrete hormones to regulate metabolism of the body, growth, development and reproduction.

內分泌系統由一些稱作內分泌腺的特別腺體組成，其主要功用是分泌激素以調節身體代謝、生長、發育與生殖。

The reproductive system differs very much in male and female. The major function of the reproductive system is for the production of offspring.

男性與女性生殖系統的構造有極大的分別。生殖系統的主要功用就是繁殖後代。