Renal Conditions Flashcards
What is the main function of the kidneys?
To regulate the extracellular fluid environment which is an important aspect of homeostasis.
What is extracellular fluid?
Fluid which exists outside of the body cells.
What is the role of extracellular fluid?
To supply body cells with nutrients such as oxygen, proteins and amino acids and removing wastes from body cells such as carbon dioxide and urea.
What is the optimum pH for extracellular fluid?
7.35-7.45
Which fluid is a major component of extracellular fluid?
Interstitial fluid
What does interstitial mean?
Between the cells
As well as interstitial fluid, what is the other major component of extracellular fluid?
The plasma in the blood.
At the arteriole end of capillary beds, which three things are squeezed out of the plasma to become interstitial fluid?
Water, electrolytes and nutrients.
At the venous ends of capillary beds which three things return to the plasma?
Water, electrolytes and waste metabolites.
Which term refers to the concentration of osmotically active particles in the plasma?
Serum osmolality
What is the main osmotically active particle in the blood?
Sodium
Which principle acts to keep sodium out of the cells?
The sodium potassium pump.
What are the risks of water entering or leaving the cell by osmosis?
Cell shrinkage or cell enlargement (swelling).
What is the key osmolality range which must be adhered to in order to prevent water from leaving or entering the cells? How is this managed by the kidneys?
275-295mmol/kg.
The kidney regulates this by excreting more or less water.
What is the average blood volume in adults?
3L
Why must blood volume be carefully regulated by the kidneys?
In order to maintain a normal blood pressure to keep blood circulating at an adequate rate.
What is blood volume determined by?
The amount of water and sodium ingested (from the diet) and the amount lost from the body (through urine).
Name three hormones produced by the kidneys?
Erythropoietin, renin and active vitamin D.
Name the 5 key functions of the kidneys:
- Produce hormones (renin, vitamin D and erythropoietin)
- Reglulation of electrolyte levels in the plasma
- Maintain blood volumes
- Maintain blood acid base balance (pH)
- Excretion of waste
- Regulation of the osmolality of the plasma
Name the 4 main componants of the renal system and their primary functions:
The kidneys: filter blood removing waste products
The bladder: stores urine prior to micturation
2x ureters: collect urine from the kidneys and convey it to the bladder
The urethra:takes urine from the bladder to outside the body
Which arteries supply the kidneys?
The renal arteries
The renal arteries are a direct branch of the…
Abdominal aorta
What are the outer and inner parts of the kidneys called?
Outer cortex
Inner medulla
Filtration is carried out by microscopic tubules called:
Nephrons
The filtrate is modified as it travels down the nephron by two processes called:
- Tubular reabsorbtion: returns substances to the plasma including water, nutrients and electrolytes
- Tubular secretion: waste products such as toxins are passed to the bladder as urine to be removed from the body
What are the four sections of the nephron in the kidney?
- Bowmans capsule
- Proximal tubule
- Loop of henle
- Distal tubule and collecting ducts
What is the role of the Bowmans Capsule within the kidneys?
To filter the plasma
What is the role of the proximal tubule in the kidneys?
The site of tubular reabsorbtion
What is the role of the loop of henle i the kidneys?
Site of further water and sodium reabsorbtion and formation of a ‘salt’ gradient in the medulla. (This gradient is essential for water conservation in the collecting ducts).
What is the role of the proximal tubules and collecting ducts within the kidneys?
‘Fine tuning’ of the filtrate occurs. The collecting duct drains into the renal pelvis.
What is the name of the knot of capillaries which is located adjacent to the kidneys?
The glomerulus
How does blood enter and leave the glomerulus?
Enters via the afferent arteriole and leaves via the efferent arteriole.
What does the efferent arteriole branch to form?
The peritubular capillaries.