Kidney and Osmoregulation - QUIZ Flashcards
Draw and label the kidney (and for each labeled structure, be able to explain its function).
Renal Artery - Unclean blood enters
Renal Vein - Clean blood exits
Medulla - Water is reabsorbed via nephrons
Cortex - Blood is filtered by glomerulus / bowman’s capsule into filtrate
Ureter - Transports urine to be stored in bladder
Draw and label a nephron (and for each labeled structure, be able to explain its function).
Bowman’s Capsule - Ultrafiltration
Glomerulus - high blood pressure due to difference in diameter in effluent / affluent arterioles
Proximal Tubule - Selective reabsorption (of glucose and others)
Loop of Henle - Creates salt gradient
Distal Tubule - Selective reabsorption (adjusts pH)
Collecting Duct - Water is reabsorbed
Explain how the structure of the glomerulus/ Bowman’s capsule facilitates its function.
F: Ultrafiltration
- The non-specific filtration of blood under extremely high pressure
- Afferent (in) arteriole is wider than efferent (out) arteriole, creates extremely high pressure glomerulus (forces blood into capsule and facilitates filtration)
- Glomerulus highly branched to increase surface area for filtration
- Glomerulus vessels contain fenestrations to allow blood contents to pass into Bowman’s capsule
- Basement membrane mesh structure prevents large substances (blood cells, proteins, platelets) from passing into the filtrate
Explain how the structure of the proximal convoluted tubule (PCT) facilitates its function.
F: Selective Reabsorption of filtrate into the lumen of PCT
Single-layer epithelial cells - decreases diffusion distance and increases diffusion rate
Microvilli on E cells - Increase SA for faster diffusion
Mitochondria - make energy for active transport
Peritubular capillary bed - for reabsorption
Explain the role of the kidney in osmoregulation / water balance / solute concentration.
- Solute concentration monitored by hypothalamus
- More water reabsorbed form filtrate because medulla is hypertonic
- ADH released into the blood by pituitary gland when water content too low (hypertonic)
- Makes walls of collecting duct / distal tubule more permeable to water (more aquaporins in membranes of the cells)
- Small volume of concentrated urine excreted
- ADH not secreted if solute content is too low (a lot of diluted urine produced)
Compare osmoregulators and osmoconformers.
BOTH; types of organisms that regulate salt concentration coring to their environment
REG - Actively maintain different solute concentrations then their environment (mammals, humans, birds)
-Takes more energy / more control
CONF - Passively maintain the same solute concentration as their environment (sharks, squid, jellyfish)
- Takes less energy / environments to live are restricted
Compare the composition of blood in the renal artery and renal vein.
BOTH; carry blood with the same amt of blood cells, proteins, and platelets
A - (dirty blood to kidney) Higher levels of:
Urea - Removed thru ultrafiltration / excretion
Oxygen - Used for ATP for active transport of essential solutes into blood
Glucose - Used in cellular respiration in kidney cells to make ATP
Sodium/Chloride - Pumped into medulla (excess is excreted) & diluted if ADH secreted
Water - To dilute urea (reabsorbed if ADH secreted)
Drugs - Excreted in urine
V- (Clean blood to body) Higher levels of:
Carbon Dioxide - waste product of cell respiration in kidney cells (making ATP for cellular respiration)
Outline an adaptation of the kidney to maintain osmolarity in desert animals.
- Longer loop of Henle in Kangaroo rats
- Most water comes from food
- Longer = more surface area so more water is reabsorbed rather than excreted in urine
Outline the use of ammonia in different types of animals.
- Fish / aquatic animals
- Toxic, needs to be diluted
- fish have unlimited access to water
- Doesn’t require much energy
Outline the use of urea in different types of animals.
- Mammals / Amphibians
- Requires less water for dilution (less toxic)
- Requires more energy than ammonia
- Short-term storage in bladder/ kidneys prevent buildup
Outline the use of uric acid in different types of animals.
- Birds / Reptiles / Insects
- Least toxic (least water needed)
- Most energy required
- Can be stored w/ embryos of developing eggs
- Needs NO water, excreted in concentrated form
Explain how insects excrete nitrogenous wastes.
- Excreted as uric acid by Malpighian tubules
- Nitrogenous waste accumulates in hemolymph
- It’s absorbed by Malpighian tubules and converted to uric acid (not toxic / requires ATP)
- Uric acid excreted in feces
Discuss the treatment options for kidney failure.
- Hemodialysis: blood drawn and filtered through dialyzer
- Semi-permiable membranes that filter out big molecules
- Dialysates fluid that removes wastes and maintains conc. gradients
- Kidney transplant: requires genetic match & immunosuppressant drugs
- Kidney grafted into abdomen & connected to vessels (usually from family)
