BRAINCAKEUltrafiltration, Selective Reabsorption and Osmoregulation.
Blood is filtered under pressure in the Bowman's capsule. The filtrate is the same composition as blood plasma except for an absence of large proteins and a lower protein concentration. Substances in the filtrate include amino-acids, urea, glucose, water and inorganic ions such as sodium, chloride and potassium ions. Glucose, amino-acids and inorganic ions are selectively reabsorbed in the proximal convoluted tubule.
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Key terms in this lesson
- Bowman's capsule
- The cup-shaped structure at the start of a nephron that encloses the glomerulus and collects the filtrate produced during ultrafiltration.
- loop of Henle
- The region of a nephron between the proximal and distal convoluted tubules that creates a concentration gradient in the medulla, enabling the reabsorption of water.
- ADH
- Antidiuretic hormone, released by the posterior pituitary gland in response to a fall in blood water potential, which increases the permeability of the collecting duct to water by inserting aquaporins.
- hormone
- A chemical messenger, secreted by an endocrine gland directly into the blood, that travels to target cells bearing complementary receptors and brings about a response.
More in Homeostasis
- Glomerulus
- Proximal Convoluted Tubule
- Loop of Henlé
- Countercurrent Multiplier
- Distal Tubule and Collecting Duct
- ADH
- Kidney failure
- Haemodialysis
All 33 lessons in Homeostasis · All AQA A-level Biology topics