HOMEOSTASIS BY THE KIDNEY FLUID AND ELECTROLYTE BALANCE Flashcards
The maintains the volume and composition of extracellular fluid, what dysfunction could arise from this
Fluid overload and metabolic derangement
The kidney does the Excretion of endogenous waste products of metabolism, what dysfunction could arise from this?
Reduction in renal excretory function (uraemia and acidosis)
The kidneys does excretion of foreign substances and their derivatives e.g. drugs and their metabolites. what dysfunction could arise from this?
Drug toxicity
The kidney produce hormones, e.g. renin, erythropoietin, and calcitriol, what dysfunction could arise from this?
Hormone function reduced
(anaemia, hypertension, etc)
What are the Functions of the Kidney?
+Volume and composition of extracellular fluid
+Excretion of endogenous
+waste products of metabolism
+Excretion of foreign substances and their derivatives e.g. drugs and their metabolites
+Synthesize prostaglandins and kinins that act within the kidney
+Production of hormones, e.g. renin, erythropoietin, and calcitriol
Which system of the body all work very closely together to maintain fluid and acid-base homeostasis (3)
The renal system, cardiovascular system and respiratory system
What can the kidney control?
Extracellular, specifically plasma, fluid volume- Effective circulating volume (ECV)
Body fluid osmolality by H2O and electrolyte control
The amount of ultrafiltrate produced in the glomeruli
The amount of H2O and electrolytes reabsorbed in the nephron and tubules
Fluid, electrolyte and H+ and HCO3- balance i.e. the amount gained minus the amount lost each day
_________ is formed at the glomerulus
Ultrafiltrate
What is the normal filtration rate?
80-120 ml/min
Does the Kidney control the extracellular or intracellular fluid volume?
Extracellular, specifically plasma, fluid volume- Effective circulating volume (ECV)
How does the kidney control the body fluid osmolality
H20 and electrolyte control
How does the kidney control the amount of urine made
controlling amount of ultrafiltrate produced in the glomeruli
controlling amount of H2O and electrolytes reabsorbed in the nephron and tubules
How much of the Ultrafiltrate formed at the glomerulus is reabsorbed back into the systemic circulation?
> 99%
Nephron controls the osmolality and volume of the urine produced through which mechanism and where?
a countercurrent mechanism in the loop of Henle
The descending limb of loop of henle are permeable to _____, but not to solutes
water
The ascending limb of loop of Henle is permeable to _____but not to water
solutes
______ is a predominantly passive process allows energy efficient ability to produce a dilute or a concentrated urine
Countercurrent Mechanism
Changes in ECV trigger which 4 effector pathways that act on the kidney
1) Renin Angiotensin Aldosterone System
(2) Sympathetic nervous system
(3) Antidiuretic Hormone (ADH) release
(4) Atrial Natriuretic Peptide (ANP) release which acts to reduce ECV
Apart from ADH, most other pathways (RAAS, SNS, ANP) use changes in ___ excretion to change effective circulating volume
Na+
How does the RAAS, Sympathetic stimulation, ADH and ANP acts on the kidneys to control effective circulating
change renal haemodynamics and Na+ transport by renal tubule cells.
_____ is group of specialised cells in distal tubule sensing sodium delivery to distal tubule
Macula densa
Central vascular receptors are blood volume receptors that detect changes in the ECV. Where are they found?
Large systemic veins
Cardiac atria
Pulmonary vasculature
Peripheral stretch receptors are baroreceptors that detect changes in ECV. Where can these be found?
Carotid sinus
Aortic arch
Renal afferent arteriole
Where are the other 2 less important baroreceptor sensors that detect changes in the ECV
CNS and liver
ADH is released by posterior pituitary gland in response to ___ and ____
hyperosmolality and volume depletion
Antidiuretic effect is mediated by _____ by acting on renal collecting ducts
V2 receptors
Which part of the Nephron is ADH most active on
Collecting ducts
In addition to ADH acting on the renal collecting ducts via V2 receptors It also increases _____ ____ mediated by ___ ___
vascular resistance
V1 receptor