E1 Take 2 Flashcards
What do excretory organs do?
Help maintain homeostasis by removing wastes from the body.
What does the urinary system include?
Kidneys (main filtering organs for blood waste removal).
What are the main functions of the kidneys?
Remove metabolic wastes (ammonia, urea, uric acid).
Maintain water balance.
How much water does the average adult lose per day?
About 2 L through sweat, urine, and exhalation.
What happens with different levels of fluid loss?
1% drop: Thirst
5% drop: Extreme pain and collapse
10% drop: Death
What happens to excess amino acids?
Undergo deamination (removal of nitrogen group) in the liver.
What toxic waste is produced by deamination?
Ammonia (NH₃).
How is ammonia made safer for the body?
Liver combines it with CO₂ to form urea (less toxic when diluted).
What is uric acid?
A byproduct of nucleic acid metabolism.
How do different organisms handle nitrogenous waste?
Fish: Excrete ammonia directly into water.
Birds/reptiles: Excrete uric acid (insoluble, requires little water).
Mammals (humans): Convert ammonia to urea.
What is the white part in bird droppings?
Uric acid (bird ‘pee’).
What are the parts of the urinary system?
Kidneys: Urine production.
Ureters: 28 cm tubes moving urine to bladder (via peristalsis).
Urinary bladder: Stores urine.
Urethra: Exits urine from the body (Males: ~20 cm; Females: ~4 cm).
What are the kidney structures?
Renal cortex: Outer section; contains Bowman’s capsules.
Renal medulla: Inner section; contains collecting ducts.
Renal pelvis: Funnel-like structure receiving urine; leads to ureter.
Nephrons: Tiny units that filter blood and create urine (~1 million per kidney).
What are the four main functions of nephrons?
Filtration
Reabsorption
Secretion
Excretion
What is the blood pathway through the kidney?
Renal artery (from aorta) → nephrons → filtered blood exits via renal vein (joins inferior vena cava).
What is the glomerulus?
High-pressure capillary bed at the start of nephron filtration.
What vessels connect to the glomerulus?
Afferent arteriole: Carries blood into glomerulus.
Efferent arteriole: Carries blood away from glomerulus.
What are peritubular capillaries?
Vessels surrounding the nephron to reabsorb water and essential solutes.
What are the main structures of the nephron?
Bowman’s capsule: Cup-like structure around glomerulus.
Proximal tubule: After Bowman’s capsule; leads to Loop of Henle.
Loop of Henle: Contains descending and ascending limbs.
Distal tubule: After Loop of Henle.
Collecting duct: Collects urine and sends it to renal pelvis.
