BY4 - Homestasis
- Created by: beth-marie2511
- Created on: 12-06-16 23:40
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- BY4 - Homeostasis
- Ultrafiltration
- Takes place in the cortex of the kidney
- It involves the glomerulus and Bowman's capsule
- Basement membrane of the glomerulus forms a selective barrier between the blood and the nephron
- 'Molecular Sieve'
- How is this created?
- Endothelium in the glomerulus contains pores, as does the basement membrane, forming the glomerulus wall
- Walls of the Bowman's capsule consists of epithelium cells called PODOCYTES.
- Filtration takes place between podocytes
- How is this created?
- The sieve allows smaller molecules through and enter the Bowman's capsule
- E.G. Urea, amino acids, glucose, water, NaCl etc.
- Larger molecules remain in the blood
- E.G. Red blood cells and plasma proteins
- 'Molecular Sieve'
- Hydrostatic pressure of the blood is HIGH in the renal artery
- Pressure is even higher in the glomerulus because of the differences between the diameter of the afferent arteriole and the efferent arteriole
- Afferent is wider than the efferent
- The higher pressure is also because of plasma proteins
- The pressure in the glomerulus capillary forces small molecules out into the bowman's capsule
- Pressure is even higher in the glomerulus because of the differences between the diameter of the afferent arteriole and the efferent arteriole
- Takes place in the cortex of the kidney
- Selective Reabsorption
- Takes place in the Proximal Convoluted Tubule
- It is the process by which useful products are reabsorbed back into the blood as the filtrate flows along the nephron
- Glucose and amino acids are completely reabsorbed in the PCT
- Most of the water is reabsorbed
- Some is collected from the Loop of Henle and the Collecting Duct
- Most of the water is reabsorbed
- Glucose and amino acids are completely reabsorbed in the PCT
- It is the process by which useful products are reabsorbed back into the blood as the filtrate flows along the nephron
- Adaptations of the Proximal Convoluted Tubule
- Microvilli
- Provides a large surface area
- Numerous Mitachondria
- ATP for active transport
- Closeness of blood capillaries
- Short diffusion pathway
- Basal Channels
- Pathway
- To maximise reabsorption
- Microvilli
- Sodium and chloride ions, glucose, vitamins and amino acids are reabsorbed in the PCT
- Water potential in the filtrate rises
- Water moves from the filtrate and into the blood by osmosis (high to low)
- Concentration of urea in the filtrate increases as it becomes a concentrated solution
- Water potential in the filtrate rises
- Takes place in the Proximal Convoluted Tubule
- Ultrafiltration
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