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Flashcards in Renal System Deck (78)
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What is the main function of the kidneys?

To extract fluid from the blood by the process of filtration and collect the fluid and change its composition by returning or keeping substances to the bloodstream or tissue fluids


For the external anatomy of the kidney, name the structures starting from the inside:

1. Renal capsule
2. Adipose capsule
3. Renal fascia


What is the following made up of and what is its function: renal capsule

Made of connective tissue. It is a physical barrier and protects against trauma whilst also helping to maintain the shape of the kidneys


What is the following made up of and what is its function: adipose capsule

Made of fat (CT). It acts as a padding - physical protection. It helps to maintain the position of the kidneys.


What is the following made up of and what is its function: renal fascia

Made of CT and it anchors the kidneys to surrounding structures


Describe the internal anatomy of a kidney:

The kidney is surrounded by a renal capsule that contains about 8-12 lobes. In each lobe there is a medullary pyramid contained in the overlying renal cortex and 1/2 of the adjacent renal columns. Between each medullary pyramid are the renal columns and between each lobe is the interlobar blood vessels. The subdivisions of the lobe are called the lobules. There are 1 million nephrons that converge into collecting ducts, then papillary ducts, then minor and major calyces. The filtrate then passes down the renal pelvis, down the ureter and into the urinary bladder


Describe the blood flow to the kidney:

The renal artery enters the kidney and divides into interlobar arteries which then arc up to form the arcuate arteries. These then form the interlobular arteries which enter into the afferent arteriole into the glomerulus. In the glomerulus there are glomerular capillaries which leave the glomerulus as the efferent arteriole. It then goes down the descending vasa recta along with the peritubular capillaries of the cortex. The blood is still oxygenated. It then goes up the ascending vasa recta where it is deoxygenated as it has passed through the peritubular capillaries of the medulla. It then joins the interlobular vein, then the renal vein, then the IVC then back to the right atrium.


Describe the structure of a nephron:

After the glomerulus is the proximal convoluted tubule which leads to the thick descending loop of henle, then the thin descending loop of henle. Then goes to thin ascending loop and then thick ascending loop of henle. Then comes the distal convolued tubule and the collecting ducts and finally the papillary ducts


What is the renal corpuscle?

A capsule on the outside of the glomerulus


What lines the afferent and efferent arterioles coming into the glomerulus?



What makes up the glomerular epithelium?

1. Visceral - podocytes (modified epithelium)
2. Capsular/urinary space
3. Parietal - forms outer wall of capsule (simple squamous)


Describe the filtration membrane from the glomerular capillaries to the capsular space:

First there are fenestrations (pores) of glomerular endothelial cells which prevents filtration of the blood cells but allows all components of blood plasma to pass through. Then there is a basal lamina layer which prevents filtration of larger proteins. Finally there is a slit membrane between foot processes called pedicels that prevents filtration of medium proteins. Eventually only small proteins make it though to the capsular space


What are the symptoms of kidney failure?

Swelling - retain water
Increased blood pressure - hypertension
Shortness of breath - fluid in the lungs


Describe the process of osmosis:

The diffusion of water through a selectively permeable membrane from an area of lower solute conc (high water conc) to high solute conc (low water conc). Eventually so much water moves in that it creates a pressure which is called the osmotic pressure (the pressure needed to stop the movement)


Describe osmolarity:

Is a measure of the effective gradient for water assuming that all osmotic solute is completely impermeant. It is a count of the dissolved particles. A measure of the osmotic pressure exerted by a perfect semi permeable membrane compared to pure water. It is dependent on the number of particles in solution - not the nature of the particles.


Describe and give and example of: hyperosmotic

A solution with a higher osmolarity than another e.g 300mM/L NaCl vs 300mM/L Urea


Describe and give and example of: isosmotic

2 solutions with the same osmolarity e.g 150mM/L NaCl vs 300mM/L urea


Describe and give and example of: hyposmotic

A solution with a lower osmolarity than another e.g 150mM/L Urea vs 150mM/L NaCl


Describe tonicity:

A functional term that describes the tendency of a cell to resist expansion of the intracellular volume. It takes into account the concentration of solute and the ability of the particle to cross a semi-permeable membrane


Describe a hypertonic solution:

A solution with a higher osmolarity than another. Water will leave the cell causing cell shrinkage


Describe a isotonic solution

2 solutions with the same POsm. No net water movement


Describe a hypotonic solution

A solution with a lower Posm than another. Water will move into the cell causing swelling and maybe lysis


Why is it important to maintain osmolarity?

Setting the membrane potential
Generating the electrical activity in nerves and muscle
Initiation of muscle contraction
Providing energy for uptake of nutrients and expulsion of waste
Generation of intracellular signalling casacdes


What is the fluid compartments in the female body solid/fluid?

45% solid
55% fluid


What is the fluid compartments in the male body solid/fluid?

40% solid
60% fluid of which 2/3 intracellular fluid
1/3 extracellular fluid of which 80% interstitialfluid
20% plasma


What are the 3 major sources of water intake?

1. Metabolic water (200mL)
2. Ingested foods (700mL)
3. Ingested liquids (1600mL)


What are the 4 major sources of water output?

1. Gi tract (100mL)
2. Lungs (300mL)
3. Skin (600mL)
4. Kidneys (1500mL)


Describe the concentrations of Na+, Cl- and Ca2+ on blood plasma, interstitial fluid and intracellular fluid:

They have a much higher concentration in the extracellular fluid than in intracellular fluid.


Describe the concentrations of K+ on blood plasma, interstitial fluid and intracellular fluid:

Much higher concentration in ICF than ECF


What are the 3 steps to forming urine?

1. Filtration at the glomerulus
2. Tubular reabsorption
3. Tubular secretion