B12 - Homeostasis In Action Flashcards
It is really important that the body keeps the level of water in the blood as constant as possible .
-If the blood becomes TOO DILUTE , then water moves into the cells by osmosis .
-If the blood becomes TOO CONCENTRATED , then water moves out the cells by osmosis .
-If the blood become TOO CONCENTRATED , then water moves by osmosis out of cells .
-If body cells gain or loose too much water by osmosis , they don;t work effiecntly .
-So the body ahs a system in place to maintain its water balance , This is part of HOMEOSTASIS .
tHE BODY taken in water through good and dirnk , but what is one wy th ebody can lose water ?
We can lose water via the LUNGS , when we EXHALE .
-The body has no way to control this water loss .
Another way the body can lose water ?
-When we SWEAT , we loose water through the ski .
-Sweat also contains ions such as sodium ion .
-It also c ontains waste porducts urea .
-The body cannot control how much water and ions and urea are lost by sweating .
-This is because , sweating is part of the body’s TEMPERATURE CONTROL SYSTEM .
What is the finaly way the body can lose water ?
-Body looses water via the kidneys in URINE .
-The body can control how mcuh water is lost in urine . So if the blood is too dilute , the kidneys remove the excess water and porduce greater volume of urine .
-As well as excess water , urea ad excess ions are also removed in the urine .
-How do the kindeys remove urea s1 ?
-Humans have two kidneys .
-Blood enters he kindey through an artery . This blood contains the waste prodcuts urea .
-How do the kindeys remove urea s2 ?
-The kindeys remove this urea , as well as ecess ions and eccess water .
-How do the kindeys remove urea s3?
This leaves the kidneys as urine , and this is stored in the bladder .
-How do the kindeys remove urea s4 ?
-Blood now leaves the kindey through a vein .
-Now the blood contians no urea .
How the kidneys adjust the lvels of molecules in the blood S1?
Blood passes thorugh the capillaries . Here , small molecules are filtered out of the blood .
-This includes urea , ions and water as well as the sugar glucose .
How the kidneys adjust the lvels of molecules in the blood S2?
These pass into a tube .
-Now all of the glucose , some of the ions and some of the water is reabsorbed back into the blood .
-Scientists call this SELECTIVE REABSORPTION .
How the kidneys adjus the lvels of molecules in the blood S3?
-Ure , excess ions and excess water re released s urine .
How has the concentration of glcuose after it passes through the kidneys changed
HAS NOT CHANGED .
-The kindeys filter glucose out of the blood then REABSORB IT ALL , back into the blood .
How has the concentration of ions after it passes through the kindeys changed ?
-Concentration of ions after pssing through the kidneys has decreased , kidneys filter ions out of the blood , but then reabsorb a certain amount of ions back into the blood dpeending on the needs of the body .
How has the concenration of urea changed fterit psses through the kidneys changed ?
The concentration of urea in the blood falls to virtuallly zero as it psses through the kidneys .
-That is becuase the kindeys filter out ALL THE UREA ,and do not REABSORB it all .
-All of the urea has been removd from the blood , the conentraiton of water and ions have been adjusted . Kindeys are carrying out HOMEOSTASIS .
How does the body deal with an excess of amino acids (1)
-Protiens are logn chins of amino acids , we fet a lot of protein into ur diet , when we digest this protein , amino acids pass into blood.
PROBLEM ; we often eat more protein , then the body needs then the the LIVER breaks down the exess amino acids and produces the chemical amino acids .
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How water levels are controlled , person exercises on a hot day (1)
-The body sweats to cool down ., This means the body is LOSING WATER .
-In other words , if the blood is too concentrated , the level of water in the blood FALLS.
-Then the pituitary gland releses the hormone ADH , into the blood stream .
How water levels are controlled , person exercises on a hot day (2)
-Adh travels to the KINDEYS , and it cuases the KIDNEY TURBULES to become MORE PERMEABLE (allows more watert to pass out the turbules.)
-This means water is reabsorbed from the rubules back into the blood .