Homeostasis Flashcards
What is the pathway in the kidney?
Bowman’s space —> proximal convoluted tubule —> descending limb of the loop of Henle —> ascending limb of the loop of Henle —> distal convoluted tubule —> collecting duct —> renal pelvis —> ureter —> bladder —> urethra
What is the structure of the kidneys?
The kidney consists of a medulla which is surrounded by the cortex. There is a renal hilum, a deep slit in the center of the kidney. The urethral pelvis spans the width of this hilum and is the widest part of the urether. The renal artery, vein and ureter exit and enter through the hilum
What is a portal system?
two capillary beds in series through which blood must travel before returning to the heart
What is a detrusor muscle?
the muscular lining of the bladder
What is the internal urethral sphincter?
consisting of smooth muscle and is contract under normal state; involuntary control
What is the external urethral sphincter?
consists of smooth muscle under voluntary control
What is the micturition reflex?
when the bladder is full, it stretches firing neurons that cause detrusor muscles to contract and the internal sphincter to relax
What are the two main functions of the kidney?
(1) Keep what the body needs and lose what it doesn’t
(2) Concentrate urine to conserve water
What does the glomerulus do?
filtered out small molecules into the urine and keeps bigger molecules like protein and blood in the bloodstream
What is filtration?
movement of solutes from blood to filtrate at Bowman’s capsule
What is secretion?
movement of solutes from blood to filtrate anywhere besides Bowman’s capsule
What is reabsorption?
movement of solutes from filtrate to blood
Which parts of the kidney are primarily concerned about the identity of the particle - keeping what is needed, losing the rest?
Bowman’s capsule
Proximal convoluted tubule
Distal convoluted tubule
Which parts of the kidney are primarily focused on the volume and concentration of urine?
Loop of Henle
Collecting duct
What does the proximal convoluted tubule (PCT) do?
amino acids, glucose, water-soluble vitamins and majority of salts are reabsorbed with water; NaCl and H2O move from the filtrate inside the PCT to outside into the bloodstream, H+,K+, ammonia and urea move from the bloodstream into the filtrate in the PCT
What does the descending limb of Henle do?
permeable to water moving out of the filtrate into the interstitium
What is the countercurrent multiplier system?
the vasa recta and nephron; the flow and filtrate and blood is opposite and therefore they avoid reaching equilibrium and are able to allow maximal reabsorption
What is the vasa recta?
a bunch of capillaries that surround the loop of Henle
What does the ascending limb of Henle do?
permeable to only salts and impermeable to water
What is the diluting segment?
where the loop of Henle gets thicker from the transition from inner to outer medulla because the cells are larger
What does the distal convoluted tubule (DCT)?
moves NaCl and H2O out of filtrate, moves H+, K+, ammonia in; concentrates urine and decreases volume; produces waste
How does aldosterone increase blood pressure?
it alters the DCT and collecting duct to reabsorb more sodium which increases the volume of water moving into the blood stream, therefore increasing the blood volume and pressure
How does ADH work?
alters permeability of the collecting duct, which allows more water to be reabsorbed by making the cell junctions of the duct leaky and water moving out of the filtrate
What is osmotic pressure?
the “sucking” pressure that draws water into the vasculature caused by all the dissolved particles
