Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Homeostasis-kidney
AQA A-level biology homeostasis year 13
| Term | Definition |
|---|---|
| Nephron | Functional unit of the kidney which selectively removes unnecessary waste products from the blood but selectively reabsorbs useful substances |
| Nephron structure (5 parts) | Renal/Bowman’s capsule (with glomerulus), proximal convoluted tubule, loop of Henle, distal convoluted tubule, collecting ducts |
| Ultrafiltration: Step 1 | Wide afferent arteriole branches out into bowl of capillaries & narrower efferent arteriole out creates high hydrostatic pressure glomerulus which forces small water soluble molecules into the renal capsule by ultrafiltration |
| Ultrafiltration: Step 2 | In the proximal convoluted tubule, most of the glomerular filtrate is reabsorbed (ions, water, & nutrients) |
| Ultrafiltration: Step 3 | The descending (thin) limb of the loop of Henle actively transports out sodium & chloride ions into the tissue fluid & since it has aquaporins it allows water to move into the filtrate by osmosis |
| Ultrafiltration: Step 4 | The ascending (thick) limb of the loop of Henle is permeable to the mineral ions but not water so it absorbs them back by facilitated diffusion which makes the filtrate very concentrated |
| Ultrafiltration: Step 5 | The distal convoluted tubule selectively secretes & absorbs different ions to maintain blood pH & electrolyte balance which can further affect water potential |
| Ultrafiltration: Step 6 | The collecting duct can reabsorb water & solutes from the tissue fluid & removes the filtrate to the bladder to form urine |
| How amino acids & glucose are removed from the filtrate & reabsorbed into the blood | When they’re forced out of the proximal convoluted tubule by Co-transport with glucose they go to the interstitial space after sodium ions are actively transported out of the tubule cell where they’re reabsorbed into bloodstream |
| What happens at the base of the loop of Henle | The interstitial fluid is so dilute that sodium ions move out on their own by facilitated diffusion |
| What happens at the top of the loop of Henle | Since so many ions are actively transported out of the ascending limb while it remains impermeable to water, by the time it reaches the proximal convoluted tubule a lot of the water diffuses out into the medulla due to it being quite concentrated |
| How the length of the loop of Henle differs in different animals | For animals which have very limited water supply, the loop of Henle will be very long to reabsorb as much water as possible into the blood which concentrates urine while the opposite is true for animals with an excess of water to get rid of it |
| Role of hypothalamus in osmoregulation | Changes in water potential are detected by osmoreceptors in the hypothalamus. If water leaves these cells by osmosis they shrivel & the hormone ADH is produced & vice versa |
| Role of posterior pituitary gland in osmoregulation | ADH moves from the hypothalamus to the pituitary gland where it is released into the blood plasma where it’s transported to the kidneys |
| Role of ADH (anti diuretic hormone) in osmoregulation | Causes more aquaporin vesicles to fuse with the membrane of the collecting duct & distal convoluted tubule membranes which makes them more permeable to water so more water leaves which further concentrates the urine |
Created by:
Study_B
Popular Biology sets