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4.6 Control Systems Co-ordination and Regulation of Processes.

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Presentation on theme: "4.6 Control Systems Co-ordination and Regulation of Processes."— Presentation transcript:

1 4.6 Control Systems Co-ordination and Regulation of Processes

2 Homeostasis What is homeostasis? Mechanisms by which a constant internal environment is maintained.

3 The urinary system Kidney Ureter Aorta Renal vein Bladder Renal artery Vena cava Urethra © 2008 Paul Billiet ODWSODWS

4 4 Kidney – structure and function Biological principles in action Deamination in Liver produces Urea…

5 5 Human kidney ureter renal artery renal vein attached here

6 1 – Filtration by the Kidney Renal artery Ureter Renal vein Supplied with blood from renal artery Inside it splits into many fine capillaries Each capillary supplies blood to hundreds of thousands of tiny filtration units called nephrons cortex Medulla

7 The blood supply

8 The cortex (view x100) Tubule (Malpighian) renal corpuscles

9 The corpuscle (view x400) Glomerulus – a ball of capillaries Bowmans capsule

10 Medulla (view x400) Tubules Capillaries


12 The nephron In the cortex In the medulla

13 The nephron Bowmans capsule Glomerulus proximal (1 st ) convoluted tubule Capillary Loop of Henlé Collecting duct Distal (2 nd ) convoluted tubule Branch of renal vein Branch of renal artery

14 1. Glomerulus brings a large surface area of blood capillaries in close contact with Bowmans capsule 2.Liquid filtered from blood under pressure (filtration) 3. Glomerular filtrate produced containing: -water -glucose -salts -urea (Protein molecules and red blood cells do not pass into tubule as they are TOO BIG!!!!) Blood from renal artery enters wide capillary Blood travels through narrow capillary towards renal vein Glomerular filtrate Filtration The blood plasma is filtered at about 150 litres per day

15 Blood plasma v Filtrate ComponentPlasma / mg 100cm -3 Filtrate / mg 100cm -3 Urea0.03 Glucose0.10 Amino acids0.05 Salts0.72 Proteins8.000

16 The nephron functions Variable permeability to water Impermeable to water Freely permeable to water

17 The nephron osmoregulation Variable permeability to water Impermeable to water Freely permeable to water Na + Na + Na + Active reabsorption H 2 O Passive osmosis 80% of water reabsorbed Ultrafiltration under pressure

18 Variable permeability to water Impermeable to water Freely permeable to water The nephron osmoregulation More and more salty H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O H2OH2O Collecting duct Loop of Henlé H2OH2O H2OH2O Na +

19 The nephron osmoregulation The blood concentration is monitored by osmoreceptors in the hypothalamus If the concentration rises the hypothalamus releases ADH ADH makes the collecting duct walls more permeable More water is reabsorbed from the filtrate as the ducts pass through the salty tissues of the medulla

20 The nephron osmoregulation The urine released into the pelvis is more or less concentrated depending upon the blood concentration Excessive sweating and eating salty food will produce concentrated urine Drinking and cold weather will produce dilute urine

21 Kidney reabsorption ComponentFiltrate / mg 100cm -3 Urine / mg 100cm -3 Urea Glucose0.100 Amino acids0.050 Salts Proteins00 © 2008 Paul Billiet ODWSODWS

22 Reabsorption Microvilli on cuboidal epithelial cells Kidney tubule with brush border Dr Millet USC Med schooll © 2008 Paul Billiet ODWSODWS

23 The afferent tubules reabsorb: 80% of water All of the glucose All of the amino acids Blood pH is regulated Blood salt levels are regulated Urea is left behind and even secreted into the tubules Reabsorbed molecules pass into the surrounding capillaries

24 Summary of kidney function

25 Controlling Water Concentration Blood -important part of internal environment -constantly changing water concentration -e.g. exercising drinking lots of water The body uses negative feedback control to regulate water content of the blood

26 How does it work?

27 Control of Water animation

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