What is osmolarity?
The number of osmotically active particles in a solution
Which two factors are needed to calculate the osmolarity?
Concentration and the number of particles the substance breaks down to
What happens to a RBC place in a isotonic solution?
Nothing
What happens to a RBC placed in a hypertonic solution?
It wil shrink
What happens to a RBC places in a hypotonic solution?
It will swell
What two compartments does total body water exist in?
Intracellular fluid and extracellular fluid
What does extracellular fluid consist of?
Plasma, interstitial fluid, lymph and transcellular fluid
When does electrolyte balance occur?
When rate of gains = rate of loss
Name 4 functions of the kidney?
Excretion - of waste and drugs
Regulation - of body fluid, ions and BP
Endocrine - Synthesis of renin, Epo,
Metabolism - Vit D metabolism, hormones
What is the functional unit of the kidney?
Nephron
What are the two types of nephron?
Cortical and juxtamedullary
Where does renal pyramid drain to?
Renal pelvis
What % of nephrons are cortical and juxtamedullary?
Cortical - 80%, juxtamedullary - 20%
What are podocytes?
Modified epithelial cells
What % of plasma is not filtered?
80%
How do you calculate rate of filtration of a substance?
Concentration in plasma x GFR
How do you calculate rate of excretion of a substance?
Concentration in urine x urine flow rate
What does rate of reabsorption =?
Rate of filtration - rate of excretion
What does rate of secretion =?
Rate of exertion - rate of filtration
What is the overall pressure of filtration?
About 10mmHg
What is the glomerular filtration rate?
Rate at which protein free plasma is filtered from the golmeruli into the bowman’s capsule per unit time
How do you calculate the GFR?
Kf (filtration coefficient) x net filtration pressure
What is a normal GFR?
125ml/min
What is the major determinant of GFR?
Glomerular capillary fluid pressure
How does vasoconstriction affect GFR?
Decreases it
If arterial BP falls how does that affect GFR?
Decreases it
What is plasma clearance?
The volume of plasma cleared of a substance per minute
How do you calculate clearance?
Rate of excretion of X/Plasma concentration of x
or
[X]urine x Vurine/ [X]plasma
What substances can be measured to determine GFR?
Inulin and creatinine
When does clearance = 0?
When a substance is filtered and completely reabsorbed
When does clearance = GFR?
When all of filtered substance is excreted
When does clearance > GFR?
When substances are filtered, secreted and not reabsorbed
When is clearance < GFR?
When substances are filtered, pertly reabsorbed and not secreted
Which kidney lies higher?
The left
Which ribs protect the kidney?
Floating 11 +12
Where do the kidneys lie in relation of the quadratus lumborum?
Anterior
Where does lymph from the kidneys drain?
Lumbar nodes
Where does lymph from the ureter drain?
Lumbar and iliac nodes
What does medulla contain?
Renal pyramids
What gives the medulla its striated appearance?
Collecting ducts
What path does urine take as it drains?
Nephrons - Collecting duct - Minor calyx - Major calyx - Renal pelvis - ureter
3 common Sites of ureteric obstruction?
Pelviuriteric junction
Ureter crossing common iliac artery
Ureteric oriffce
What supplies glomerulus?
Afferent arteriole
What is the name for loops of blood vessels in the medulla?
Vasa recta
What lines the distal convoluted tubule?
Columnar epithelium
Which cells secrete rennin?
Juxtaglomerular cells
What cell lines most of the urinary tract?
Transitional epithelium
3 parts of male urethra?
Prostatic, membranous, penile
How much of the seminal fluid volume comes from the prostate?
About 50%
Where do ureters pass in relation to the common ilia vessels?
Anterior
What muscle forms the bladder wall?
Detrusor muscle
Why does the internal urethral sphincter in males contract during ejaculation?
To prevent retrograde ejaculation
What are the two routes of catheterisation?
Urethral, suprapubic
Which zone of the prostate causes most cancer?
Peripheral
What are the 3 cylinders of tissue in the penis?
Corpus cavernosum x2 , corpus spongiosum
What is the blood supply to the scrotum?
Internal pudenal artery
Where does lymph from scrotum and testes drain?
Inguinal lymph nodes
Where does lymph from the testes drain?
To lumbar nodes
Is golmerulonephritis usually diffuse or focal?
Diffuse
What causes pylonephritis?
Bacterial infection
Commonest bacteria in pylonephritis?
E. coli
Most common cause of urethral obstruction in males?
Prostatic disease
What stain may show TB mycobacteria?
Zeehl neilsen stain
What type of bacteria usually causes cystitis?
Coliforms
What can a schistosomiasis infection predispose you to?
Urethral malignancy - SCC
Main causes of hydronephrosis?
Obstruction and reflux
What does ascending limb of the loop of hence reabsorb?
Na and Cl
What is the descending limb highly permeable to?
Water
What do loop diuretics block?
Triple co transporter
What is agenesis?
Absence of one or both of the kidney
What complication may be seen in pregnancy In a baby with renal agenesis?
Too little amniotic fluid
What is infantile polycystic kidney disease inherited?
Autosomal recessive
How is adult polycystic disease inherited?
Autosomal dominant
What benign kidney tumour may cause secondary hypertension?
Juxtaglomerular cell tumour
What does renal cell carcinoma arise from?
Tubular epithelium
Where is renal cell ca likely to spread?
Renal vein
What is the commonest symptom of transitional cell carcinoma?
Haematuria
What is late collecting duct permeable to and when?
Water in presence of ADH
What initiates mictruition reflex?
Stretch receptors
What drain the vessel leaves the glomerulus?
Efferent arterioles