11.3 Flashcards
Define osmolarity
Osmolarity refers to the solute concentration of a solution
Define osmoregulators
Osmoregulators are animals that maintain their internal environment regardless of the external environment
- Most animals are osmoregulators
Define osmoconformers
Osmoconformers are organisms that change according to their external environment
- Animals whose internal solute concentration tends to be the same as the concentration of solutes in the environment
How are nitrogenous wastes produced?
Nitrogenous wastes are produced from the breakdown of…
- Amino acids (a part of proteins)
- Nucleic acids
What are the 3 types of waste molecules that the amine group (NH2) is incorporated into?
- Ammonia
- Urea
- Uric acid
How do insects carry out osmoregulation and the removal of nitrogenous wastes?
The Malpighian tubule system
- Tubes that branch off from their intestinal tract (Malpighian tubules)
What is osmoregulation?
It is a form of homeostasis whereby the concentration of hemolymph or blood in the case of animals with closed circulatory systems is kept within a certain range
What is hemolymph?
Arthropods have a circulating fluid, known as hemolymph
It is a combination of
- The characteristics of tissue fluid
- Blood
Waste products of any type of organism must be excreted out, explain the toxicity of each nitrogenous waste and how it is excreted
- Ammonia; Very very very very very very toxic
- Urea; not that toxic
- Uric acid; not toxic
The more toxic the waste molecule is, the more water it requires to dilute it
- Leading it to be excreted out of the organism
What do the cells lining the Malpighian tubules do?
Actively transport ions and uric acid from the hemolymph into the lumen of the tubules
What happens to the water and salt in the process of excretion in the Malpighian tubule?
Water is drawn out by osmosis from the hemolymph through the walls of the tubules into the lumen
- The tubules empty their content into the gut
- Both water and salts are reabsorbed into the hind gut while the nitrogenous waste is excreted with the feces
What is the function of the kidneys?
- Osmoregulation
- Excretion
They are responsible for removing substances from the blood that are not needed or are harmful
What is the difference between the composition of blood in the renal artery and the renal vein?
Renal artery; Where blood enters the kidney
Renal vein; Where blood leaves the kidney
There are substances that are present in higher amounts in the renal artery than the renal vein
What are the substances that are presented in higher amounts in the renal artery than the renal vein?
- Toxins and other substances that are ingested and absorbed but are not fully metabolised
- Excretory wast products; Including nitrogenous waste products
- Excess water, produced by cell respiration/ absorbed from food in the gut
- Excess salt, absorbed from food in the gut
What is the removal of excess water and salt a part of?
Ultrafiltration
The process of excretion
Describe the difference in the water and or salt content in the blood in the renal artery and the renal vein
Blood in…
Renal artery; Contains more water and salt content but in a lower concentration
Renal vein; Contains more constant concentration of water and salt because osmoregulation has occurred
What does the kidney filtrate and absorb and where are the filtrated substances found?
Filtrate
- It filters off about one fifth of the volume of plasma from the blood flowing through them
- Filtrate contains all of the substances in plasma apart from large protein molecules
Absorb
- It actively reabsorbs the specific substance in the filtrate that the body needs
The unwanted substances can only be presented in the renal artery and NOT the renal vein!!!
How does the metabolic activity of the kidney affect the difference between the composition of blood in the renal artery and the renal vein?
Oxygen
Blood leading the kidney = deoxygenated
Blood entering the kidney = oxygenated
- The kidney metabolism requires oxygen
Glucose
More in renal artery than in renal vein
Due to the fact that some glucose is used by the metabolism of the kidney
What is not filtered by the kidney and is presents in the same concentration in both blood vessels?
Plasma proteins
What is the use of the ultra structure of the glomerulus and the Bowman’s capsule?
To facilitate ultrafiltration
Describe the pressure in the capillaries in the glomerulus of the kidney
- Pressure in the capillaries is particularly high
- The capillary wall is particularly permeable; Making the volume of the fluid forced out to be about 100 times greater than in the other tissues
What is the name of the fluid forced out of the capillaries of the glomerulus of the kidney?
Glomerulus filtrate
What is ultrafiltration?
The separation of particles differing in size by a few nanometers
What is the podocyte and what is it’s function?
A strangely shaped cell with finger-like projections which wrap around capillaries in the glomerulus and provides support
A barrier through which waste products are filtered from the blood
What are the 3 parts to the ultrafiltration system?
- Fenestration
- The basement membrane
- Podocytes
If particles passes through all 3 parts
They become part of the glomerular filtrate
Explain what fenestration is
Fenestrate = Transparent area
Fenestrations between the cells in the walls of the capillaries
They allow fluid to escape but NOT blood cells
Explain what the basement membrane is and what it is made out of
The basement membrane that covers and supports the wall of the capillaries
It is made of negatively-charged glycoproteins
- Which forms a mesh
It prevents plasma proteins from being filtered out
- Due to their size and negative charges
What are podocytes and what do they form?
Podocytes
- Are highly specialized cells of the kidney glomerulus
- Wraps around capillaries and that neighbor cells of the Bowman’s capsule
- forms the inner wall of the Bowman’s capsule
- Helps prevent small molecules from being filtered out of the blood in the glomerulus
What is the the proximal convoluted tubule and what is its role?
It is the first part of the nephron
It selectively reabsorbs useful substances by active transport
The glomerulus filtrate floes into the proximal convoluted tubule
What are the 4 things that the proximal convoluted tubule absorb and how does it absorb it?
- Sodium ions; By active transport from filtrate to space outside the tubule
- Chloride ions; Attracted form filtrate to space outside the tubule because of charge gradient set up by active transport if the sodium ions
- Glucose; Is co-transported out of filtrate and into fluid outside the tubule
- Water; Pumping salutes out of filtrate and into the fluid outside the tubule creates a solute concentration gradient, causing water to be reabsorbed from filtrate by osmosis
Describe the structure of the proximal convoluted tubule
Outermost layer; The basement layer
- Invaginations (folds) of the outer membrane
Mitochondria near the basement layer
Microvilli surrounding the lining of the tubule wall
Lumen containing filtrate
What is the basic functional unit of the kidney?
The nephron
- A tube with a wall consisting of 1 layer of cells
- The wall is the last layer of cells that substances cross to leave the body, it is an epithelium
List the 6 main parts and the 6 blood vessels of the nephron
- Proximal convoluted tubule
- Bowman’s capsule
- Loop of Henlé
- Distal convoluted tubule
- Collecting duct
- Blood vessels
- Afferent arteriole
- Glomerulus
- Efferent arteriole
- Peritubular capillaries
- Vasa recta
- Venules
What is the Loop of Henlé?
It is a tube shaped like a hairpin consisting of a
- Descending limb that carries the filtrate deep into the medulla of the kidney
- Ascending limb that brings the filtrate back out to the cortex
What is the role of the Loop of Henlé?
It maintains hypertonic conditions in the medulla
The overall effect of the Loop is to create a gradient of solute concentration in the medulla
What is urine made up of?
Water and dissolved waste
Where is urine going to accumulate?
In the renal pelvis which drains it into a tube called the ureter
Where can you find the nephron?
In the cortex and the medulla of the kidney
Most of the nephron is located in the cortex, the Loop of Henlé can be found in the medulla part
What does the role of the renal artery?
Where filtered oxygenated blood enters from the heart
What is the role of the renal vein?
Where filtered deoxygenated blood exits the kidney
What are the 6 main parts of the kidney?
- Renal cortex
- Renal artery
- Renal vein
- Medulla
- Ureter
List the 9 parts of the nephron
- Glomerulus
- Bowman’s capsule
- Afferent arteriole
- Efferent arteriole
- Proximal convoluted tubule
- Loop of Henlé
- Distal convoluted tubule
- Collecting duct
- Peritubular capillary bed
What is the nephron and around how many nephrons can be found in the kidney?
Nephron is the main filtering unit of the kidney
There are over 1,250,000 nephrons in each kidney
What is the glomerulus and what is it responsible for?
It is a capillary network, responsible for filtering the blood
What is the Bowman’s Capsule?
The circular hand shaped structure found at the beginning of the nephron
It surrounds the glomerulus
List the 3 parts of the tubule in the nephron
- Proximal convoluted tubule
- Loop of Henlé
- Distal convoluted tubule
Which arteriole in the nephron has a bigger opening and why?
The afferent arteriole
If the exit opening is a lot smaller than the opening where the blood goes in, the pressure will be a lot higher within the Bowman’s capsule
The pressure created is going to push stuff out of the blood vessels
How does the pressure created in the glomerulus by the arterioles help with filtration and what does it have to do with Bowman’s capsule?
The capillaries of the glomerulus have fenestrations (holes)
The high pressure helps push and force shit out of the blood vessels through the holes
The shit that gets forced out is going to end up in the Bowman’s capsule
What are some substances that cannot pass through the fenestrations of the glomerulus?
Shit that are too big. These stuff remains in the blood vessel
1. Blood cells
2. Proteins
What part of the nephron is selective filtration and which part isn’t selective reabsorption?
Isn’t selective filtration
- The glomerulus; Shit’s filtrated purely because of the pressure built up inside the vessel
Selective reabsorption
- The convoluted tubule
Describe the process of the reabsorption of salt ions in the proximal convoluted tubule
Salt ions are actively pumped from the lumen into the cells of the tubule then pumped into the peritubular capillary bed
This process requires ATP, produced by the mitochondria
Describe the process of the reabsorption of water in the proximal convoluted tubule
The amount of water reabsorbed by the process of osmosis depends on how much salt there is in the lumen
The more salt ions leave the tubule, the more water leaves
If a lot of salt is reabsorbed, then a lot of water will also be reabsorbed
What happens if glucose is found in the lumen of the proximal convoluted tubule?
There should be no glucose in the urine, if there is, diabetes
Any glucose that is in the filtrate coming from the glomerulus needs to be pumped back into the capillary bed and returned to the bloodstream
BY ACTIVE TRANSPORT
What is the job of the kidney?
To maintain homeostasis
By keeping the blood plasma isotonic to the blood cells
^This makes sure that we don’t get out of osmotic balance
Define isotonic solution
An isotonic solution is any external solution that has the same solute concentration and water concentration compared to body fluids
List 3 things that the kidney depend on when it comes to the elimination of water
- How much water is ingested
- How much you sweat
- How rapidly you’re breathing (cause there’s moisture in our breath)
What’s the difference between the environment of the cortex and the medulla?
The medulla has a ridiculously high concentration of ions
Describe the environment inside the Loop of Henlé and outside of the Loop
Outside
- Super super super high conc of ions
Inside the Loop of Henlé
- Low conc of ions
- High water content
When salt ions are pumped out, the salt conc in the Loop of Henlé would decrease
By the time the filtrate reaches the Distal tubule, the Loop will have a high water content
Explain why the Loop of Henlé creates a hypotonic environment in the kidney?
- The medulla the Loop dips down into has a SUPER HIGH conc of ions
- Meaning that the interior of the loop is hypotonic compared to the medulla
- Salt ions are pumped out by active transport, making the filtrate even more hypotonic
- Some water leaves through the Loop but the filtrate exiting the loop will still have a VERY HIGH water content
Define hypotonic
Having a low concentration of salt and a super super high water content
What is ADH?
Antidiuretic Hormone
Helps regulate the amount of water in the body
Explain why ADH controls the reabsorption of water in the collecting duct?
The fluid entering the collecting duct is technically urine, but it still has way too much water
The collecting duct has different levels of permeability to water depending on the hormone ADH
Where is ADH produced and what does it do to the tubules in the kidney if ADH is present?
ADH is produced by the posterior pituitary gland in the brain
If ADH is present, the tube becomes more permeable to water, more water leaves the filtrate and returns to the bloodstream
If ADH is NOT present, the tube becomes impermeable to water so NO water leaves the filtrate
When will the pituitary gland produce ADH?
The pituitary glans will produce a lot of ADH when you are…
- Sweating
- Not having enough water
The pituitary will shut off the ADH when there is enough water in our bloodstream
- Well hydrated
What does transparent urine indicate?
What does it mean in terms of ADH production?
The lighter the colour of the urine, the more diluted the urine is
Meaning that there is enough water
If the excreted urine has a very dark yellow colour, that means that there is a high amount of ADH and the water cwas being absorbed back into the bloodstream
Explain how the length of the Loop of Henlé relates to the adaption for water conservation
The longer the Loop, the more water will exit the filtrate and return to the bloodstream
- Because the Loop dips down into the very hypertonic medulla
Describe the length of the Loop of Henlé in aquatic animals
Animals that live in aquatic environment have short Loops of Henlé (or none at all)
- Because they don’e need to conserve water
They are literally surrounded by water…
Describe the length of the Loop of Henlé in desert animals
Desert animals have a very long Loop of Henlé
- So that most of the water in their filtrate can return to the bloodstream
- Reducing their need for water intake
- They pee very little!!!
What changes do the kidneys make to the substances found in blood? After the filtration process
The substances listed below entered from the renal artery and its amount have lowered
Meaning that the blood passed out of the renal vein has a lower amount of the shit listed below
- Urea
- Salt ions
- Water
- Oxygen level
The substance that’s concentration stays the same in the blood is (cannot find these in the urine)
- Glucose
- Protein
- Blood cells
Osmoregulators
Osmo = osmosis
Regulate = Actively regulate/ control
Organisms that actively regulate/ control the rate of osmosis
Organisms whose tissues/ blood have a different solute concentration to their environment
Osmoconformers
Have tissues that have the same solute concentration as their environment
What does it mean by kidney failure?
Kidney failure means the kidneys are no longer functioning well enough to effectively filter the blood
Describe kidney failure in the case of toxic substance build ups
If the blood isn’t being filtered enough, toxic substances will build up in the blood stream and the osmotic balance will be disrupted
e.g of toxic substance
- Urea
What are the 2 options for patients that are experiencing kidney failure?
- Dialysis
- The patien’s blood is pumped out of the body and into a device (a fake kidney) that has a membrane filter that filters the blood
- The device also has a solution to control the osmotic balance - Kidney transplant
- Donor kidney must match the patient (blood type and other factors)
- Can live with one kidney
- The recipient of the kidney must be on immune suppressing drugs for the rest of their life because the kidney isn’t yours, recognising the cells as non-self
- Immune system will try to attack the non-self kidney
What are the chemical composition of urine?
- Water
- Salt ions
- Urea
What does the present of glucose in the urine indicate?
The proximal convoluted tubule did not absorb all the glucose meaning there is too much sugar in the blood
Diabetes
What does the present of blood cells in the urine indicate?
Blood cells are too large to fit through the fenestrations of the glomerulus
Indicating, kidney malfunction, bleeding in the renal tubes
from kidney stones
What does the present of proteins in the urine indicate?
Whole proteins are usually too large to fit through the fenestrations of the glomerulus, if protein is found in urine…
Might indicate, high blood pressure pushing the proteins through the fenestrations or a bunch of other si orders that affect the glomerulus
What does the present of drugs in the urine indicate?
*Drugs are types of toxins
Drugs are WEIRD cause they don’t enter from the normal pathway, through the glomerulus
They enter from the proximal convoluted tubule from the bloodstream
Indicating that a person has been taking drugs because after the proximal convoluted tubule part, there is no selective reabsorption/ filtration anymore so the drug passes out through the ureter without being filtrated
What happens if you’re dehydrated?
If dehydrated…
Blood plasma is going to be hypertonic (because there’s less water in it) compared to your blood cells
- Not enough water intake to cope with water loss
- Sleepiness
- Constipation; Large intestine is absorbing water from your shit to compensate for the lack of water that we were able to reabsorbed through the kidneys
- Dry mouth
- Dizziness
What happens if you’re dehydrated?
If overhydrated…
Blood plasma is going to be hypotonic (because there’s too much water in it) compared to your blood cells
- Confusion
- Blurry vision
- Muscle cramping
- Nausea
