Osmoregulation and The Excretory System Flashcards
(23 cards)
Describe the permeability of cell membranes in relation to water.
Cell membranes are generally permeable to water, meaning they lack control over the movement of water across their membranes, making cells susceptible to changes in volume and pressure based on the surrounding solute concentration.
Explain the effects of a hypotonic solution on plant and animal cells.
In a hypotonic solution, there is too much water inside the cell, causing plant cells to become turgid (normal state) and animal cells to become lysed.
Define isotonic solution and its effects on plant and animal cells.
An isotonic solution has the same amount of water both inside and outside the cell, resulting in flaccid plant cells and normal animal cells.
What happens to cells in a hypertonic solution?
In a hypertonic solution, there is more water outside the cell, leading to plasmolyzed plant cells and shriveled animal cells.
Explain the role of kidneys in excretion.
The kidneys filter out wastes from the blood, allowing a fraction of the blood plasma containing concentrated wastes to be excreted from the body.
Describe the processes involved in kidney filtration.
Kidney filtration involves three main processes: filtration, reabsorption, and secretion. What is not reabsorbed is left behind in the urine.
What is deamination and where does it occur?
Deamination occurs in the liver, where the amino group is removed from each amino acid that comes from the breakdown of a protein.
Explain the conversion of the amino group during deamination.
The amino group removed during deamination is converted to ammonia, while the remaining part of the amino acid, mainly carbon and hydrogen, is oxidized to produce energy.
Describe the blood supply to the kidneys.
Blood is supplied to the kidneys through the renal artery, which carries blood that needs to be filtered.
How does clean blood exit the kidneys?
Clean blood exits the kidneys through the renal veins after the filtration process.
What is the renal pelvis and its function?
The renal pelvis is a hollow cavity that connects the kidney to the ureter, allowing urine to pass to the urinary bladder.
Explain the pathway of urine from the kidneys to the outside of the body.
Urine passes from the kidneys through the ureters to the urinary bladder and exits the body through the urethra.
Describe the initial stage of urine formation.
Urine formation begins at Bowman’s capsule, where the filtration of blood takes place.
Describe the role of the kidneys in filtering blood plasma.
The kidneys filter the entire contents of human blood plasma 65 times in a day, removing waste and regulating the balance of water, ions, and nutrients.
Explain the process of reabsorption in the kidneys.
Reabsorption involves the recovery of 65% of water, 100% of glucose, and 100% of amino acids from the filtrate back into the bloodstream.
How do specialized ion pumps function in the nephron?
Specialized ion pumps transport potassium, sodium, and chlorine from the filtrate into the fluid surrounding the tubule, aiding in ion balance.
Define the function of microvilli in the renal tubule.
Microvilli are the inner walls of the tubule that increase the total surface area available for the reabsorption of solutes.
What role do aquaporins play in kidney function?
Aquaporins are membrane proteins that facilitate the movement of water by forming passages for water molecules to flow out of the tubule.
Explain how nutrients and water are reabsorbed in the proximal convoluted tubule.
Nutrients and water reabsorbed in the proximal convoluted tubule enter the peritubular capillaries, returning them to the bloodstream.
Describe the function of the loop of Henle in urine formation.
The loop of Henle reabsorbs additional water by osmosis and aquaporins, further concentrating the urine.
How is waste secreted during urine formation?
Waste is secreted at several points in the nephron, including the active secretion of H+ ions and the passive secretion of detoxified poisons from the liver.
What is the significance of H+ ion secretion in the kidneys?
H+ ions are actively secreted to help balance the acidity generated by metabolic reactions in the body.
Explain the kidney’s role as a safe valve in regulating body acidity.
The kidneys can act as a safe valve by secreting excess H+ ions into the collecting ducts when acidity rises, which are then excreted in the urine.
