Lecture 23 4/29/14 Flashcards
Countercurrent Multiplier Mechanism
Is a system that allows the kidneys to concentrate solutes within its medulla.
How does the countercurrent multiplier work?
- NaCl is pumped out of the filtrate in the ascending limb of the loop of henle
- Because the ascending limb and the descending limb are in close proximity to each other the increase in solute concentration form the NaCl is felt at both of the limbs and the loop of henle
- This results in an increase osmotic gradient outside the descending limb, which pulls water out of the descending limb and into the peritubular space
- As water leaves the descending limb, the osmotic concentration within the limb increases, which provides an ample amount of NaCl to be actively transported as this filtrate reaches the ascending limb. This cycle continues, which means that the medullary region will always by hyperosmotic in order to pull water out of the kidney tubule.
Aldosterone
is produced in the adrenal glands.
job is to retain sodium. Pulls sodium out of the distal convoluted tubule and along with that, water comes along with it
Increases the number and activity of Na-K pumps in the walls of the DCT.
Function is to return Na to the peritubular space from the filtrate and excrete K in the urine.
Excess production of the aldosterone can cause life threatening hypokalemia from excess secretion of K.
Renin
produced by kidneys. Causes conversion of angiotensin to Angiotensinogen I and to Angiotensionogen II.
In response to low blood pressure and volume
Goes through the Lungs and goes through to ACE.
Causes the release Aldosterone, ADH, Thirst Drive, and Renin
ADH
Part of the Angiotensin pathway.
Job is to work on the collecting ducts.
Increases the permeability of the collecting ducts to H2O. Functions to remove water from the filtrate.
Diabetes Insipidus
Decrease levels of ADH. Or deficiency of ADH.
Can significantly increase the production of urine. Can produce gallons and gallons of urine per day. 12-15 liters.
Vasa Recta
A group of arterioles and capillaries that surround the juxtamedullary nephron.
Function is to return reabsorbed filtrate back to the blood.
Blood Flow of the Vasa Recta flow where?
Flow in the opposite direction to the loop of Henle, which serves to facilitate the removal of H2O and solutes from the pertubular spaces and return them to the blood.
Ureter
Renal Pelvis dumps into the ureter
10-12 inches long - depends on height
Retroperitoneal
Urine sweats off papilla
Function of Ureter
Transports urine from the kidneys to the urinary bladder via peristalsis
Peristaltic movement of urine from the renal pelvis (kidneys) to the urinary bladder.
3 Coats of the Ureter
Inner - Mucosal - transitional epithelium
Middle - longitudinal and circular
Outer - fibrous - continues with renal capsule and peritoneum
Urinary Bladder
Hollow muscular organ
Posterior to symphasis pubis - serves to protect it.
Anatomy of Urinary Bladder
Ureter openings
Rugae of Mucosa
Trigone - No rugae, no pleating
Internal Sphincter
External Sphincter
4 Coats of Urinary Bladder
Mucosa
Submucosa
Detrusor Muscle
Serosa
Mucosa of Urinary Bladder
Innermost - mucous membrane
Transitional Epithelium - lining the ureters and bladder. Able to stretch. Transitions from the cuboidal to squamous
Submucosa of Urinary Bladder
Dense connective tissue. Deeper layers. Connects mucosal layer to deeper muscle.
Detrusor Muscle of Urinary Bladder
3rd Layer which is under parasympathetic controls.
Inner - longitudinal
Middle - circular
Outer - Longitudinal
Serosa Peritoneum of Urinary Bladder
Covers only bladder top. Outer layer.
Micturition Reflex
Bladder fills to 200-400 ml.
Stretch receptors send signals to the cord causing contraction of detrusor muscle and relaxation of internal sphincter. Involuntary relax.
