BIOL1008 Lecture 23: Lecture 23
9 Jun 2018
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Lecture 23: Excretion
Examples of types of waste and where they are produced
- Undigested food in the large intestines (faeces)- removed by defecation e.g. cellulose
- Excess ions and water
- Bilirubin (breakdown of haemoglobin)
- Metabolism produces wastes
Kidney functions
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Kidneys
- Body contains 5L of blood (passes through both kidneys more than350x per day)
- Kidneys filter about 180L fluid/filtrate from the blood per day
- 99% reabsorbed
- 1% (1-2L) forms urine to be excreted
- Main structures of urinary system- kidney, ureter, urinary bladder, urethra
- Micturition reflex
Nephron- tubules
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Document Summary
Examples of types of waste and where they are produced. Undigested food in the large intestines (faeces)- removed by defecation e. g. cellulose. Body contains 5l of blood (passes through both kidneys more than350x per day) Kidneys filter about 180l fluid/filtrate from the blood per day. 1% (1-2l) forms urine to be excreted. Main structures of urinary system- kidney, ureter, urinary bladder, urethra. Peritubular capillaries arterial end goes glomerulus down ascending loop of henle venule end goes up descending loop of henle. Movement of filtrate from glomerulus (high pressure) to bow(cid:373)a(cid:374)"s capsule (low pressure) At this stage, glomerular filtrate contains nutrients, salts, wastes and water. Blood cells and large proteins remain in glomerulus. Na +, amino acids, vitamins, glucose (active transport) pct (mitochondria release atp) peritubular capillaries. Water (passive transport, osmosis) along with solutes. All glucose is removed in this process exception e. g. diabetes. Tubule (low conc. solutes) medulla venue (high conc. )
