What is the functional unit of the excretory system?
The nephrons (tube).
What does renal mean?
Kidney.
What are peritubular capillaries?
The capillaries surrounding the nephrons.
Where do the parts of the blood that were not passed by the bowman's capsule go to?
Blood leaves via Efferent arterioles and wraps around nephron (peritubular capillaries)
What is Aldosterone?
Aldosterone is a hormone that makes the walls of the distal tubule more permeable to sodium ions, allowing sodium to be reabsorbed into the blood, making chlorine ions and water follow it too. Overall, aldosterone just allows sodium, chlorine, and water to leave the distal tubule.
If ADH reaches the collecting duct, it makes the walls of the collecting duct more permeable to water, allowing for reabsorption. Where does this water go to when this happens?
It leaves the duct and goes to the salty medulla (water always follows salty areas) and eventually joins the bloodstream.
Which parts of a nephron are in the medulla and which parts aren't?
Parts of nephron in medulla: Collecting ducts, and loop of Hemle.
Parts of nephron not in salty medulla: Glomerulus, bowman's capsule, proximal tubule, and distal tubule.
What does ADH stand for?
the antidiuretic hormone.
Why are hydrogen ions either dumped into the kidney or reabsorbed by the blood from the kidney?
To balance blood PH.
What are some examples of some diuretics?
Coffee, nicotine, and alcohol.
Describe diuretics.
Diuretics are drugs that put more sodium and salt into urine, consequently resulting in water being secreted into the urine to counteract the salts. Due to this, the urine ultimately becomes more watery which can lead to dehydration (this is because water is being taken from your body and put into urine).
What do antidiuretic hormones do to the collecting ducts (mostly) and the distal tubules?
They increase the permeability of the collecting duct to water, allowing the water from the filtrate to leave the duct and move into the salty medulla to eventually be reabsorbed into the blood. Due to this, urine concentrates.
Where do antidiuretic hormones do their job?
At the collecting duct (MOSTLY) and at the distal tubule.
Even though most of the blood's contents were filtered out at the glomerulus, some wastes still remain. What happens to these wastes?
Any excess wastes still in the blood (ammonia, drugs, hydrogen ions (for PH) ) are secreted into the distal tubule via active transport and leave the body in urine.
In the loop of Henle, reabsorption of what occurs?
Major water reabsorption occurs, and small sodium ion reabsorption adjustments are made.
In the proximal tubule, majority reabsorption of what occurs?
Amino acids, Glucose, water, sodium ions, and chlorine ions.
What is the unique scenario that arises when it comes to the reabsorption of sodium ions from the nephrons into the blood?
So, when Na+ ions are pumped back into the blood from the nephrons (until threshold level is reached), Chlorine ions (Cl-) or bicarbonate ions (HCO3-) follow to balance out the positive charge of the Na+ to prevent the pH in the blood from becoming imbalanced. When this happens, the sodium ions naturally bond with the chlorine ions, forming salt. Due to this, water follows and also enters the blood stream from the nephron. This maintains salt concentration homeostasis/equilibrium. Due to the water leaving, the urine becomes more concentrated, giving it more of a yellow color.
As humans, we do not want useful substances to just pass through nephrons and be excreted. So, how is this prevented?
The useful substances in the nephron are reabsorbed back into the blood via diffusion (smaller molecules such as water or amino acids) or active transport (bigger molecules such as glucose)
Is there any useful substances in the filtrate?
Yes
True or false: Reabsorption ONLY takes place in the proximal tubules and the loop of Henle.
False. Reabsorption can also happen in the distal tubules and the collecting duct.
What is filtrate?
Whatever manages to pass through/into the capsule
What can move through the bowman's capsule? What can't? Why?
Small particles such as water, ions, amino acids, glucose, and waste can move through into the capsule while large particles such as RBC's, white blood cells, proteins, and platelets cannot. This is because these particles are too big to go through the bowman's capsule.
The glomerulus dips into______ where_____
The glomerulus dips into the Bowman's capsule where the blood inside is filtered
Why does blood enter the glomerulus at a high pressure?
So that ALL of the blood is forced into the nephron; if we were to depend on diffusion, 50% would come in, 50% would stay in the capillaries.
LABELLLLLLLLLLLLL
Where does secretion take place?
In the distal tubes and the collecting ducts.
Where does reabsorption mainly happen in the nephron?
In the proximal tubules and the loop of henle.
When does filtration take place in the kidney?
When the blood reaches the glomerulus and is filtered by the bowman's capsule
What does the Bowman's capsule do?
The bowman's capsule acts like a pasta strainer and allows plasma and the things in the plasma to flow through it but not the bigger cells such as RBC's or WBC's.
What is the glomerulus?
It is a ball of vessels that is surrounded by the bowman's capsule.
What do Afferent Arterioles do?
They supply the nephrons with blood to be filtered. They wind into a ball called the glomerulus.
How many nephrons are in each kidney?
1 million.
Everywhere there is a nephron, ________
a capillary surrounds it.
1. Nephron
2. Cortex
3. Medulla
4. Renal artery
5. Ureter
6. Renal vein
What is the renal pelvis?
It is an area in the middle of the kidney which connects to ureters. (more specifically, it connects the collection ducts to the ureters)
Why is the medulla so salty?
For water control through osmosis. (if there is a lot of water in the nephrons, the water will diffuse into the medulla through osmosis.)
What is the medulla?
The medulla is the inner layer beneath the cortex. It is very salty and it contains the other part of the nephron (the other part is in the cortex)
What is the cortex?
The outer layer of connective tissue that encircles the kidneys (contains part of nephrons)
Label the parts:
1. Kidney
2. Ureter
3. Bladder
4. Urethra
Describe the ureters.
Ureters transport the filtered wastes from the blood in the kidneys to the bladder.
Describe the bladder.
The bladder holds urine, there are sphincters at the bottom of the urinary bladder. Additionally, if there is 200mL in the bladder, you will get a weak signal to empty, at 400mL you will get a stronger signal, and at 700mL, the body takes over and sends urine to the urethra.
Describe the kidneys.
They are paired (you only need 1 to survive), they are 0.5kg each, and they hold one fourth of the body's blood. Also, they are located right underneath the very bottom rib at the back.
What are some examples of the nitrogenous wastes that are removed by our kidneys?
Ammonia, uric acid, and urea.
How do the kidneys maintain our blood pH
By adding H+ ions when the pH is too high and by removing H+ ions when the pH is too low.
What are the three jobs of the kidneys?
Maintain water balance, Maintain blood pH, and remove wastes from the body (especially nitrogenous wastes)
What condition is represented by this picture?
Gout.
What happens if there is an excess amount of uric acid?
it will precipitate out of the blood plasma and form crystals in the joints (gout)
True or false:
Uric acid is relatively soluble
False. Uric acid is relatively insoluble
Which metabolic pathway produces the substance that requires the most water needed to be excreted?
The ammonia pathway
Which metabolic pathway requires the most energy to produce?
The uric acid pathway.
Where are urea and uric acid removed from?
the kidney.
What's another way that urine can be formed in the human body other than ammonia getting turned into urea?
The body can break down nucleic acids into uric acid (this is much less common in mammals more common in birds or reptiles)
What is the benefit of getting ammonia turned into urea?
Urea is much less toxic than ammonia.
What is the chemical formula for ammonia getting turned into urea?
2NH3 + CO2 -----> CO (NH2)2 + H2O
what is the difference between the kidneys and the liver when it comes to their jobs?
The liver breaks down waste while the kidneys remove waste.
What does the liver do the ammonia it produced due to deamination?
It takes the ammonia and turns it into urea (which is a big part of pee)
Which part of the amino acid is turned into ammonia and which part is used for energy?
The amine group is turned into ammonia as it is the part that is removed from the amino acid during deamination. The part that is used for energy is the carbon skeleton.
Why is the production of ammonia due to deamination bad?
Ammonia is toxic.
What is a byproduct of deamination?
Ammonia (NH3). (a hydrogen atom attaches onto the NH2 removed from the amino acid, turning it into NH3.)
Where does deamination take place?
In the liver.
What is deamination?
Deamination is the removal of an NH2 group from an amino acid in order to break it down for energy (processing proteins)
Why are the kidneys considered to be a part of the excretory system? (what does it excrete)
because the kidneys excrete nitrogenous wastes in urine.
Why is the liver considered to be a part of the excretory system?
Because the liver excretes bile pigments in bile.
Why are the lungs considered to be a part of the excretory system?
Because the lungs excrete carbon dioxide as a gas
Why is skin considered to be a part of the excretory system?
Because skin excretes water and salt during perspiration (sweating)
What body parts does the excretory system include?
The kidneys, the skin, the liver, the lungs, the intestines, etc...
(really anything that secretes something)
What is considered as "waste" in the excretory system?
Any substances that the body does need or use.
What do kidneys do?
Kidneys regulate the composition of body fluids (blood) by removing metabolic wastes while retaining proper amounts of water, salt, nutrients, etc... (blood filtration)
What are the symptoms of Bright's disease?
bloody urine and increased urine output.
Describe a kidney transplant.
A new kidney is inserted and is hooked up to the ureters and the blood vessels. In kidney transplant, the old kidney is not removed (it does not rot and is completely fine to leave in the body). Additionally, humans can live with just one kidney.
Pig's kidney cells are put into dialysis machines. Why?
To release needed hormones, and regulate pH and electrolyte levels.
True or false:
Both hemodialysis and peritoneal dialysis work via diffusion.
True
What is peritoneal dialysis? describe it.
Peritoneal dialysis is when the kidney is bathed in dialysate fluid. In peritoneal dialysis, fluid is pumped into the peritoneal space where wastes can join the fluid. Then, this fluid and the waste products now inside of it are drained from the peritoneal space. This cycle keeps on repeating and is a bit more flexible than hemodialysis.
What is hemodialysis? Describe it.
Hemodialysis is when you are hooked up to a fake kidney and your blood is artificially filtered. In hemodialysis, blood is pumped from an artery in your body to a dialyzer where waste products are filtered from the blood through an artificial membrane into a fluid called dialysate. The purified blood is then pumped from the dialyzer into the artery and this cycle keeps happening.
When is dialysis used?
When someone has renal failure.
Where do the kidney stones usually form?
At the end of the nephron.
What happens if you try to pee with a kidney stone?
the urine is barely removed and slowly moves the kidney stone until the kidney stone comes out along with your urine.
What can happen if you have a kidney stone? How do you treat them?
It can become lodged in your ureters or renal pelvis (tearing the tissue as it moves when you try to pee). To treat kidney stones, ultrasounds can be used to blast them into smaller pieces.
When do kidney stones form?
when your urine contains more crystal-forming substances (such as calcium, oxalate, and uric acid) than the fluid in your urine can dilute.
What is Bright's disease/nephritis?
It is a broad disorder involving the inflammation of the nephrons. It typically involves damage to the glomerulus (due to microbes, disease, etc....) which changes its permeability, allowing everything in the blood to pass through the Bowman's capsule including RBC's. This is why Bright's disease's symptoms include bloody urine and and increased urine output.
What is the only thing Mr. Kralka could be bothered to write about in the slide about diabetes insipidus?
Urine output increases.
What causes diabetes insipidus?
A defect in anti-diuretic hormone producing cells in the hypothalamus (brain) or the nerve cells connecting hypothalamus to the pituitary gland (which releases ADH into the blood)
What are the similarities between type 1 and 2 diabetes mellitus?
Both include symptoms of thirst, frequent urination, and blurry vision, both require a healthy lifestyle and medical supervision, and if any of them are left untreated, they can progress into further complications.
describe the differences between type 1 and type 2 diabetes mellitus.
Type 1: usually caused by autoimmune or genetic causes, involves a non functional pancreas resulting in no insulin being produced. Also, type 1 diabetes mellitus cannot be prevented and cannot be reversed.
Type 2: This is usually caused by obesity or aging, it involves a PARTIALLY functioning pancreas where SOME insulin is produced. Also, type 2 diabetes mellitus can be prevented through life style changes and can be reversed through early diagnosis.
What are the treatment options for diabetes mellitus?
Islet cell transplant in pancreas or an insulin injection
what are the symptoms of diabetes mellitus?
watery, sugar urine (due to more sugar in the blood in the nephron leading to water following too.), excess urination (because there is more water in the urine), dehydration (water is joining urine and isn't being used well by the body), and fatigue.
What does diabetes mellitus result in?
Diabetes mellitus results in high blood sugar, which means that there will be more sugar in the nephron, which means that water will follow the sugar into the nephron (through osmosis to balance out concentrations) and joins the urine. This can result in dehydration because your body's water is just joining urine and is not being used for bodily processes.
What is the benefit of insulin?
It breaks down glucose and turns it into glycogen, allowing us to store glucose instead of just disposing of it through urine.
When does diabetes mellitus occur?
When the body does not make enough insulin from the pancreas.
What is the kidney?
The kidneys are organs that exchange matter and energy with the environment.