Excretory System Flashcards
What are bile pigments?
Broken down red blood cells
What is eliminated by the urinary system?
- Urea and ammonia NH3 (metabolites of amino acid metabolism)
- Creatinine (muscle metabolism product)
- H2O (aerobic metabolism)
What is micturition?
Urination
The rate that the kidneys filter blood is proportional to?
The amount of volume within blood vessels (intravascular blood volume) and blood pressure
Osmotic pressure is important at Bowman’s capsule
What are the two components of the renal corpuscle?
- Bowman’s capsule
- Glomerulus
What are the three layers that blood plasma must be filtered through to get to bowman’s capsule?
- Endothelial layer of capillary wall
- Glomerular basement membrane
- Podocytes (negatively charged cells) in Bowman’s capsule, which helps repel negative proteins (as most are)
Where does the body actively reabsorb compounds and water from filtrate in the nephron? What is a consequential feature of this area?
Proximal convoluted tubule
There is a microvilli brush border for maximal surface area.
What are some substances that are secreted into the proximal convoluted tubule?
- H+
- Urea
- Penicillin
What is the purpose of the loop of Henle?
To concentrate the filtrate by transporting sodium and chlorine ions into the medulla (producing an osmotic gradient).
The osmotic gradient will pull water from the filtrate and into the renal medulla
What part of the nephron is most subject to the effects of hormones on reabsorption?
Distal convoluted tubule can be effected for facultative reabsorption of ions and water
Aldosterone causes the DCT to absorb sodium and potassium (causing retention of water)
How does antidiuretic hormone (vasopressin) concentrate urine?
Increasing the permeability of the DCT and the collecting ducts allowing the medulla to draw water out by osmosis. Water returns to the circulation via a system of vessels called the vasa recta
What part of the kidney secretes renin?
Juxtaglomerular cells at the macula densa (near the beginning of the DCT)
The juxtaglomerular cells and the macula densa are known as the juxtaglomerular apparatus
