Excretion Flashcards
Define excretion
Excretion is the removal of toxic waste substances made by cells. Toxic, waste and Cells are key words!
What is the difference between excretion and egestion?
Excretion is removal of waste products from cells Whereas Egestion is passing out of waste material passed through alimentary canal
Respiration occurs in all living organisms both plants and animals. What is the waste products of respiration ?
Carbon dioxide
Plants both respire and photosynthesise. Does this mean that oxygen and carbon dioxide go into the leaves, or out of the leaves or both in and out?
Both oxygen and CO2 go in and out of leaves. Oxygen taken in and CO2 out for respiration CO2 in and oxygen out for photosythesis
Humans cannot store excess amino acids like they can store carbs and lipids. (As fat tissue). So excess amino acids need to be broken down. What is the process of breaking down amino acids called?
Deamination
What are the two waste products that need to be excreted?
Carbon dioxide Urea
What process produces carbon dioxide as a waste product?
Respiration
What removes carbon dioxide?
The lungs via blood plasma
What process produces urea as the waste product?
Breakdown of amino acids ( deamination)
In what organ are excess amino acids broken down and what waste product is produced?
In the liver producing waste product of urea
What organs remove urea?
Kidneys and skin
How does the liver break down excess amino acids?
Amino acids filtered into the liver through the hepatic artery Excess amino acids are broken down into carbohydrates and ammonia Ammonia is very toxic so broken down into urea which is less toxic Useful amino acids and the urea released back into blood via hepatic vein
The kidneys filter the blood, remove any excess materials and passes them to the bladder. Where in your body are your kidneys and what shape are they?
Central of body cavity shaped like kidney beans!
What are the 3 main sections of the kidney?
Cortex - at the top and lighter colour Medulla- triangular shaped Pelvis - yellowy section
The kidney contains millions of tiny structures called…
Nephrons
List in order the 6 parts of a nephron.
Glomerulus, Bowman capsule, Proximal convoluted tubule, Loop of Henle, Distal convoluted tubule, Collecting duct
The artery exiting the glomerulus is smaller diameter than the entrance. This builds up pressure. What does this pressure force into the bowmans capsule?
Small molecules such as urea, glucose, amino acids and salts cross into the bowmans capsule to form the glomerular filtrate
Which large molecules do not pass into the bowmans capsule but stay in the blood?
Proteins and red blood cells
From the bowmans capsule, the filtrate travels to the proximal convoluted tubule. Here specialist cells use active transport to pump useful materials back into the blood. What 2 key materials are pumped back into the blood?
All the Glucose 80% of the water
Your kidneys filter 180L of water a day but how much urine is produced per day?
1.5L
What 2 parts of the kidney are used to reabsorb water?
Loop of Henle Collecting duct
If you are dehydrated, your body will try to reabsord as much water from the filtrate as it can. What does this do to the urine?
Lower volume of water in urine makes it darker browner colour
Your body controls how much water the body reabaorbs. What hormone controls this and where is this hormone produced?
Anti diuretic hormone ADH produced in the pituitary gland which is controlled by the hypothalamus in your brain.
Anti diuretic hormone ADH is carried in the blood. The collecting duct is surrounded by capillaries, how does the ADH control how much water is reabsorbed back into the blood?
The ADH released by the pituitary gland diffuses out of the blood and binds with receptors on surface of collecting duct cells. This triggers the collecting duct wall to become more permeable to water so more is reabsorbed.
