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Questions and Answers
What is the role of afferent and efferent arterioles in the mammalian kidney?
What is the role of afferent and efferent arterioles in the mammalian kidney?
- Afferent arteriole removes blood from the glomerulus, while efferent arteriole brings it in
- Afferent arteriole brings blood to the glomerulus, while efferent arteriole removes it (correct)
- Both afferent and efferent arterioles bring blood to the glomerulus
- Both afferent and efferent arterioles remove blood from the glomerulus
What is the normal diameter relationship between afferent and efferent arterioles?
What is the normal diameter relationship between afferent and efferent arterioles?
- Their diameters are inversely proportional to each other
- They have the same diameter
- The afferent arteriole has a larger diameter (correct)
- The efferent arteriole has a larger diameter
How does the higher resistance in the efferent arteriole affect GFR?
How does the higher resistance in the efferent arteriole affect GFR?
- It fluctuates filtration
- It decreases filtration
- It increases filtration (correct)
- It has no effect on filtration
What are the intrinsic mechanisms used to regulate GFR?
What are the intrinsic mechanisms used to regulate GFR?
When are intrinsic mechanisms used to regulate GFR?
When are intrinsic mechanisms used to regulate GFR?
How do marine mammals like dolphins obtain their water?
How do marine mammals like dolphins obtain their water?
What is the term used for animals that can adapt to a wide range of salinities?
What is the term used for animals that can adapt to a wide range of salinities?
In freshwater, how do teleost fish counteract obligatory solute movement?
In freshwater, how do teleost fish counteract obligatory solute movement?
How do teleost fish in saltwater excrete excess ions?
How do teleost fish in saltwater excrete excess ions?
What process yields nitrogenous waste products in animals?
What process yields nitrogenous waste products in animals?
What is the main function of the kidneys in teleost fish osmoregulation?
What is the main function of the kidneys in teleost fish osmoregulation?
What is the primary function of aldosterone in the mammalian kidney?
What is the primary function of aldosterone in the mammalian kidney?
Which cells in the distal tubule or collecting duct are affected by aldosterone?
Which cells in the distal tubule or collecting duct are affected by aldosterone?
What is the net effect of aldosterone activity in the distal tubule or collecting duct?
What is the net effect of aldosterone activity in the distal tubule or collecting duct?
What is the function of atrial mechanoreceptive fibers in the mammalian heart?
What is the function of atrial mechanoreceptive fibers in the mammalian heart?
What is the role of stretch-sensitive secretory cells in the mammalian heart?
What is the role of stretch-sensitive secretory cells in the mammalian heart?
What is the effect of atrial natriuretic peptide (ANP) on the kidney?
What is the effect of atrial natriuretic peptide (ANP) on the kidney?
What is the main function of basolateral Na+/K+ ATPase in proximal tubule cells?
What is the main function of basolateral Na+/K+ ATPase in proximal tubule cells?
What is the function of aquaporins in the descending limb of the loop of Henle?
What is the function of aquaporins in the descending limb of the loop of Henle?
What is the significance of the thick ascending limb of the loop of Henle being impermeable to water?
What is the significance of the thick ascending limb of the loop of Henle being impermeable to water?
What is the function of loop diuretics like Furosemide in the loop of Henle?
What is the function of loop diuretics like Furosemide in the loop of Henle?
What is the role of countercurrent exchange in the loop of Henle?
What is the role of countercurrent exchange in the loop of Henle?
What distinguishes a juxtamedullary nephron from a cortical nephron?
What distinguishes a juxtamedullary nephron from a cortical nephron?
What is the primary function of the collecting duct in the nephron?
What is the primary function of the collecting duct in the nephron?
What triggers the production and secretion of anti-diuretic hormone (ADH) from neurosecretory neurons?
What triggers the production and secretion of anti-diuretic hormone (ADH) from neurosecretory neurons?
How does ADH impact water reabsorption in the distal tubule and collecting duct?
How does ADH impact water reabsorption in the distal tubule and collecting duct?
What is the primary requirement for cell survival?
What is the primary requirement for cell survival?
What is the difference between Osmoconformers and Osmoregulators?
What is the difference between Osmoconformers and Osmoregulators?
Which of the following factors contribute to obligatory osmotic exchanges?
Which of the following factors contribute to obligatory osmotic exchanges?
How do small animals differ from large animals in terms of hydration and dehydration?
How do small animals differ from large animals in terms of hydration and dehydration?
Which of the following factors contribute to the permeability of the integument (body covering)?
Which of the following factors contribute to the permeability of the integument (body covering)?
What is the role of metabolic water in osmotic exchanges?
What is the role of metabolic water in osmotic exchanges?
What is the primary function of the mammalian kidney?
What is the primary function of the mammalian kidney?
How do teleost fish in seawater maintain hydration?
How do teleost fish in seawater maintain hydration?
What is the role of active epithelial transport in osmoregulation?
What is the role of active epithelial transport in osmoregulation?
What is the difference between obligatory and controlled osmotic exchanges?
What is the difference between obligatory and controlled osmotic exchanges?
Study Notes
Osmoregulation in Animals
- Body fluids constitute the immediate environment for cells and molecules
- The composition of body fluids provides the context in which cells, organelles, and molecules function
- The major requirement for cell survival is the retention of appropriate quantities of water
- Water is the most important inorganic constituent in living cells
- Enzyme activity depends on the degree of hydration
- Water is a solvent for organic and inorganic substances
- Water determines the volumes of cells and tissues
Osmoregulators and Osmoconformers
- Osmoregulators maintain the levels of ions and body fluid across changing environmental levels
- Osmoconformers' internal levels of ions and water fluctuate with levels in the environment
Osmotic Exchanges
- Osmotic exchanges occur between an animal and its environment through:
- Transepithelial diffusion
- Ingestion
- Defecation
- Metabolic water production
- There are two types of osmotic exchanges:
- Obligatory osmotic exchanges (occur in response to factors over which the animal has little or no physiological control)
- Controlled osmotic exchanges (physiologically regulated to aid in maintaining homeostasis)
Factors Contributing to Obligatory Osmotic Exchanges
- Gradients between external and internal environments
- Surface area to volume ratios
- Permeability of the integument (body covering)
- Feeding, metabolic water, and excretion
Endocrine Regulation of Mammalian Kidney
- Aldosterone regulates Na+ reabsorption and K+ secretion by binding to cytosolic receptors in cells of the distal tubule or collecting duct
- Aldosterone activity:
- Increases Na+ and K+ channel synthesis and insertion in apical membrane
- Increases synthesis and number of Na+/K+-ATPases in basolateral membrane
- Net effect: more Na+ and water reabsorption (smaller urine volume produced)
Mammalian Kidney
- Nephron is the functional unit of the kidney
- Nephron has five major regions:
- Bowman's capsule
- Proximal tubule
- Loop of Henle
- Distal tubule
- Collecting duct
- Loop of Henle has three regions:
- Descending limb
- Thin ascending limb
- Thick ascending limb
- The countercurrent multiplier system multiplies the osmotic gradient between the filtrate and interstitium
Elimination of Nitrogenous Wastes
- Amino acid catabolism yields nitrogenous waste products, which are toxic to the animal
- Nitrogenous wastes are excreted through the kidney
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Description
Test your knowledge on iono- & osmoregulation in animals with this quiz. The quiz covers topics such as osmoregulatory challenges on land, mammalian kidney structure and function, endocrine regulation, elimination of nitrogenous wastes, and osmoregulation in aquatic animals.
