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Excretory system
The document summarizes the human excretory system. The skin and kidneys are the main excretory organs, with the kidneys filtering blood and removing waste from the body. The kidneys regulate water and salt concentrations in the body through a process called osmoregulation. The basic unit of the kidney is the nephron, which filters blood and selectively reabsorbs nutrients while excreting waste as urine. Urine is stored in the bladder and released through the urethra.
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Excretory system
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- 2. Excretory organs Skin The skin is a part of the excretory system: it releases sweat, which helps cool the body and regulate the concentration of salt. The salt helps the water evaporate, cooling off the skin. The skin is made up of a lot of layers. Kidneys The kidneys are placed on either side of the spinal column near the lower back. They are primarily responsible for filtering blood by removing nitrogenous wastes, though they also regulate blood pressure in a process called osmoregulation.
- 3. Controlling the Internal Concentrations Water moves in and out of cells by osmosis The maintenance of the balance in water and salts is known as OSMOREGULATION
- 4. THE KIDNEY Theurinary system is made-up of the kidneys, ureter, bladder, and urethra. The kidneys are bean-shaped organs, each about the size of a fist They are located near the middle of the back, just below the rib cage, one on each side of the spine Every day, a person’s kidneys process about 200 quarts of blood to sift out about 2 quarts of waste products and extra water. The wastes and extra water become urine, which flows to the bladder through tubes called ureters. The bladder stores urine until releasing it through urination.
- 5. Overview of functionof Kidney Blood flows to kidney via the renal artery The blood is filtered and the following materials enter the kidney tubules 1. water 2. salt 3. Urea 4. glucose
- 6. Every thingthat the body needs in reabsorbed including some water and all the sugar and mineral ions needed by the body. The amount of water reabsorbed is dependent on the amount that it needs The waste; urea, water and excess mineral ions that are not needed are released in the urine
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- 9. The Nephron Itsprincipal function is to control the absorption of water and soluble substances such as sodium salts by filtering the blood, reabsorbing what is required and excreting the rest as urine.
- 11. Structures of thenephron BOWMAN’S CAPSULE: the site of ultrafiltration of the blood. This is done by force generated when the blood flowing in a larger vessel is forced into smaller capillaries. The walls of the capillaries acts as a filter Blood cells and protiens are too large to pass through the gaps Water, salt, glucose, urea and mineral ions pass through
- 12. GLOMERULUS: The knotof blood vessels in the bowman’s capsule where the pressure builds up so ultrafiltration occurs.
- 14. FIRST CONVOLUTEDTUBULE The fluid that enters from the Bowmans Capsule is known as the Glomerular filtrate A lot of reabsorption takes place here All the glucose ~67% sodium ions 80% water
- 15. LOOP OFHENLE This is where the urine is concentrated and more water is reabsorbed
- 16. SECOND CONVOLUTEDTUBULE This is where the main water balance is done If the body is short of water then more is reabsorbed ADH is involved The remaining salt is reabsorbed here
- 17. COLLECTING DUCT The urine is collected here No glucose is present The level of salt and water depends on the diet Very high concentration of urine Reabsorption of water can take place here if it is badly needed. ADH is responsible
- 18. The urinethen passes through the URETER to the BLADDER. The bladder is a muscular bag which stores the urine until we let it out. The urine then passes the URETHRA to the outside world as we urinate
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- 22. SUMMARY OFSTRUCTURES involved in urine production Renal artery – glomerulus – bowman’s capsule – proximal convolution – loop of henle – distal convolution – collecting duct – ureter – bladder – urethra - toilet