Respiratory / Excretory / Digestive — Key Terminology

1.Trachea is supported by C-shaped cartilage rings. Bronchus splits into left and right. Bronchioles have smooth muscle that can constrict — that is asthma. Alveolus is the gas exchange site, where surfactant reduces surface tension. Diaphragm contracts and descends during inhalation.

氣管 trachea 由 C 型軟骨環支撐。支氣管 bronchus 分左右兩條。細支氣管 bronchiole 有平滑肌可收縮——氣喘的成因。肺泡 alveolus 是氣體交換處，表面活性劑 surfactant 降低表面張力。橫膈膜 diaphragm 吸氣時收縮下降。

2.Oxyhemoglobin is oxygen bound to hemoglobin. Carbonic anhydrase catalyzes CO2 plus water to carbonic acid to bicarbonate plus proton — critical for CO2 transport.

氧合血紅素 oxyhemoglobin 是 O2 與血紅素結合。碳酸酐酶 carbonic anhydrase 催化 CO2 加水為碳酸再為碳酸氫根加質子——CO2 運輸關鍵。

3.Bohr effect: when pH drops, CO2 rises, or temperature rises, the oxygen dissociation curve shifts right — releasing more oxygen to active tissues like exercising muscle.

波爾效應 Bohr effect：當 pH 下降、CO2 上升、或溫度上升，氧解離曲線右移——釋放更多 O2 給活躍組織如運動中的肌肉。

4.Nephron is the functional unit of the kidney. Glomerulus performs filtration — small molecules filtered from plasma. Bowmans capsule collects the filtrate.

腎元 nephron 是腎臟功能單位。腎絲球 glomerulus 進行過濾——血漿中的小分子被濾出。鮑氏囊 Bowman capsule 收集濾液。

5.Proximal convoluted tubule PCT: highest reabsorption — glucose, amino acids, sodium, bicarbonate, water. Loop of Henle establishes the medullary osmotic gradient via countercurrent multiplier.

近曲小管 PCT：再吸收最多——葡萄糖、胺基酸、鈉、碳酸氫根、水。亨利氏環 Loop of Henle 建立髓質滲透梯度，靠逆流倍增機制。

6.Distal convoluted tubule DCT: regulated by aldosterone for sodium reabsorption and PTH for calcium reabsorption. Collecting duct: regulated by ADH for water reabsorption — concentrates urine.

遠曲小管 DCT：受 aldosterone 調控鈉再吸收、PTH 調控鈣再吸收。集尿管 collecting duct：受 ADH 調控水再吸收——尿液濃縮。

7.Renin is secreted by the kidney and starts the RAAS system: Renin, Angiotensin, Aldosterone System.

腎素 renin 由腎臟分泌，啟動 RAAS：腎素—血管收縮素—醛固酮系統。

8.Year one fourteen exam point: glomerular filtration only filters small molecules — water, electrolytes, glucose, amino acids, urea. Proteins and blood cells are NOT filtered. Protein in urine, called proteinuria, indicates glomerular damage.

114 年考點：腎絲球過濾只濾出小分子——水、電解質、葡萄糖、胺基酸、尿素。蛋白質和血球不會被濾出。尿中出現蛋白質叫 proteinuria，代表腎絲球損傷。

9.Salivary amylase works at neutral pH and breaks down starch. Pepsin works at acidic pH around two and is activated from pepsinogen — digests protein in the stomach.

唾液澱粉酶在中性 pH 工作，分解澱粉。胃蛋白酶 pepsin 在酸性 pH 約 2 工作，由胃蛋白酶原 pepsinogen 活化——在胃中消化蛋白質。

10.Pancreatic juice contains trypsin, lipase, amylase, and nuclease. Bile is produced by the liver, stored in the gallbladder, and emulsifies fat — note that bile contains NO enzymes.

胰液含 trypsin（蛋白酶）、lipase（脂肪酶）、amylase（澱粉酶）、nuclease（核酸酶）。膽汁由肝臟製造、膽囊儲存，乳化脂肪——注意膽汁不含酵素。

11.Villi increase small-intestine absorption surface area. Microvilli, the brush border, further increase surface area. Lacteal is the lymphatic vessel that absorbs fat as chylomicrons.

絨毛 villi 增加小腸吸收面積。微絨毛 microvilli 即刷狀緣，進一步增加面積。乳糜管 lacteal 是淋巴管，以乳糜微粒形式吸收脂肪。