Renal System: Salt and Water Balance Flashcards
What is the primary function of the renal system in marine turtles?
eliminate waste products and regulate the electrolyte composition of blood.
Where are the kidneys located in marine turtles?
caudally in the coelom beneath the ventral carapace.
How do marine turtles’ kidneys differ from those of mammals?
Unlike mammals, marine turtles have a cloaca that processes urinary and digestive waste together.
What are the three regions of the cloaca?
coprodeum, urodeum, proctodeum.
What does the term “cloaca” mean?
The term “cloaca” is derived from Latin and means “sewer.”
What is the function of the renal corpuscle in a nephron?
filtering blood plasma.
How many nephrons do marine turtles have compared to humans?
Marine turtles have thousands of nephrons, while humans have about one million.
What is the significance of the difference in nephron length among species?
Nephrons in reptiles are smaller in length compared to those in birds and humans.
What are the components of a nephron?
renal corpuscle and renal tubule.
What is glomerular filtrate?
the fluid filtered from blood into Bowman’s Capsule.
What is the role of afferent and efferent arterioles in the nephron?
The afferent arteriole brings blood to the glomerulus, while the efferent arteriole drains blood away.
How do kidneys help manage blood pressure?
by adjusting blood volume through urine concentration.
What hormone helps the body retain water?
Antidiuretic hormone (ADH)
What waste product do reptiles primarily excrete from nitrogen metabolism?
Reptiles primarily excrete uric acid as a waste product
Why is uric acid excretion an advantage for reptiles?
conserves water, which is crucial for survival in arid conditions.
What components does reptile urine typically contain?
sodium (Na+), chloride (Cl-), and urea, among other ionic constituents.
What is the function of salt glands in marine reptiles?
remove excess salt from the body, especially when ingesting seawater.
How is blood flow regulated in the kidneys?
constricting the diameter of capillaries within the kidneys.
What are the major routes of water loss for aquatic reptiles?
respiratory tract, kidneys, gut, integument.
How do sea turtles maintain internal ionic homeostasis?
various physiological mechanisms and structural devices.
What factors can affect the acid-base balance in reptiles?
Temperature and metabolic byproducts, like lactic acid
What are the components of the renal blood circulation in reptiles?
afferent and efferent arterioles, along with renal portal system.
How much fluid does a green sea turtle’s kidney filter per kilogram of body weight?
340 ml of fluid per kilogram.
What is the effect of dehydration on kidney function in reptiles?
kidneys reabsorb as much water as possible and produce concentrated urine.
Why do reptiles lack the ability to concentrate urine like mammals?
Reptiles lack the loop of Henle, which is the structure that allows urine concentration in mammals.
What happens to urine composition during increased hydration in reptiles?
Well-hydrated reptiles produce a higher volume of dilute urine
What role does the bladder play in reptilian urinary systems?
storage structure for urine; connected to cloaca via urethra.
How does temperature affect blood pH in reptiles?
Increased body temperature is associated with decreased blood pH, affecting acid-base balance.
What is the primary defense against salt loading in sea turtles?
“incidental drinking” to minimize salt water intake.
What is the primary component of sea turtle tears?
chloride and sodium.
How do marine turtles cope with respiratory water loss?
reduced humidity in the air they breathe from the ocean’s surface.
What are the two types of keratinous proteins found in reptilian skin?
alpha keratin (hair-like) and beta keratin (feather-like).
What adaptations do reptiles have to minimize water loss through their skin?
Reptilian skin is composed of keratinous layers that provide resistance to water diffusion.
How does elevated blood lactate affect blood pH during dives?
leads to decrease in blood pH, compromising balance and viability.
What allows turtles to survive arid conditions with limited water access?
The production of uric acid minimizes water loss during excretion.
Why is the examination of blood and urine composition crucial for understanding reptilian physiology?
reveals insights into hydration status and metabolic processes in reptiles.
What is the unique feature of the renal portal system in reptiles?
provides a second route for blood to return from the body to the kidneys and heart.
How do reptiles manage electrolyte balance in their bodies?
Kidneys excrete or conserve ions based on their concentrations in the blood, maintaining balance.
What happens to water reabsorption when a person consumes a lot of water?
Kidneys reduce water reabsorption, allowing excess water to be excreted in urine.
What role does the renal medulla play in kidney function?
inner part of the kidney, involved in urine concentration and fluid balance.
How does the presence of glomeruli in turtles differ from those in birds?
Turtles have poorly developed glomeruli with fewer capillaries per body weight compared to birds.
How do marine turtles’ adaptations impact their survival in their environment?
Their adaptations for water conservation and salt excretion are critical for survival in marine habitats.
What physiological changes occur in the kidneys during dehydration?
kidneys reduce filtration rates and reabsorb more water to prevent further dehydration.
What is the typical urine composition of reptiles regarding ions?
Reptilian urine typically has sodium, chloride, and various waste products depending on hydration status.
What are the implications of salt gland function in hatchlings compared to adults?
Hatchlings have larger salt glands relative to brain mass to cope with seawater intake upon emergence.
How does the kidney filtration process affect overall fluid balance in reptiles?
impacts water retention and waste elimination, crucial for maintaining fluid balance.
What role does the urinary bladder play in the urinary system of reptiles?
stores urine and connects to cloaca for waste excretion.
