Key facts Flashcards
What muscles does the kidney rest on?
Quadratus lumborum, psoas major
What artery blocks the ascension of the kidneys in the “horseshoe kidney” deformity?
IMA
What vertebral level do the kidneys start from and end?
Left - T11 - L2
Right - T12 - L3
What do the ureters pass on the way down to the bladder? (2 things)
Common iliac bifurcation AND
Men: Vas deferens
Women: Uterine artery
What is the standard GFR? What is its units?
125ml/min
Name 5 Kidney functions
- Control extracellular fluid concentrations/electrolyte balance
- Produce EPO/Renin
- Manage blood pH
- Metabolise Vitamin D
- Excrete waste products
What are the components of the trigone?
- Internal ureteric sphincters
- Internal urethral meatus
What is the bladder attached to the umbilicus via?
The Urachus
What is the definition of Osmolality?
The number of molecules per kilogram of solvent
What is the definition of Osmolarity?
The number of molecules per litre of fluid
What is an Osmole?
A molecule which does not cross the membrane freely
Where does secretion into the PCT come from?
Peri-tubular capillaries
What is the apical side of the lumen?
The inside
What is the basolateral side of the lumen?
The outside
What transporter is most common within the kidney on the basolateral side?
NaK/ATPase
What transporter is very useful in the PCT?
NaK/ATPase
What type of cells does the PCT have?
Simple Cuboidal with Brush Border
Name 3 things that are obligately reabsorbed in the PCT
- Glucose
- Amino acids
- H+
Name 3 apical channels in the PCT
Na-H exchanger
Na-Glucose exchanger
Na-AA exchanger
What is the dominant anion in the PCT by the end?
Cl-
What channels are in the Loop of Henle?
NKCC2
ROMK
Na/KATPase
How would you describe the fluid exiting the Loop of Henle?
Hypotonic
What are the main channels in the DCT?
NCC (NaCl)
ENaC
What are the main channels in the CD?
ENaC
Name 3 Pre-Renal causes of AKI
Cardiogenic shock, Hypovolaemic shock, Normovolaemic shock
Name 3 Intra-renal causes of AKI
Nephrotoxic drugs:
- NSAIDs (ACE if already bad)
- Rhabdomyelosis (myoglobin)
- Acute glomerulonephritis
Name 3 Post-renal causes of AKI
- Renal calculi
- Bladder cancer
- BPH
Name 4 causes of CKD
- Diabetes
- Hypertension
- Obesity
- Age
What does a urine dip test for? (7)
pH, nitrites, leucocytes, blood in urine, glucose, ketones, protein
What does the Kidney develop from embryologically?
Urogenital ridge of the intermediate mesoderm
What germ layer does the kidney develop from?
Intermediate mesoderm
Name the 3 stages of kidney development
- Pronephros
- Mesonephros - sprouts ureteric bud
- Metanephros
What does the kidney do after development?
Undergoes caudal-cranial shift - L4-T11
What separates the urogenital sinus from the hindgut?
The urorectal septum
What would a low amniotic fluid in a pregnant woman suggest?
Renal agenesis (bilateral)
What is Hypospadias?
Urethral fold fusion error - hole on underside of the penis
Name 3 imaging modalities used to check the kidney?
US guided biopsy
CT
IV angiogram
Name the sequential naming progression of the kidney blood supply to the nephron
- Segmental
- Interlobar
- Arcuate
- Interlobular
- Afferent
- Efferent
- Peri-tubular capillaries
Describe the 3 layers of the glomerular filter
- Endothelial layer with fenestrations
- Glomerular basement membrane
- Podocytes with pedicels
What charge is the glomerular basement membrane and what does this help with?
Negative - repels negatively charged proteins to prevent proteinuria
Name the two autoregulation responses within the kidneys
- Myogenic autoregulation
- Tubular glomerular feedback
Describe the myogenic autoregulatory response
Afferent arteriole is vasodilated
Describe the tubular glomerular feedback response
Macula dense in the DCT, checks Na concentration
If reduced GFR: Renin and Prostaglandins released
If raised GFR: Increased Na+ -> ATP release -> Adenosine -> Afferent vasoconstriction
How much does GFR raised in pregnancy? What is the mechanism for this called?
150%
Compensatory hypertrophy
Define “Clearance”
The amount of plasma cleared per unit time
What is the equation for the excretion rate?
Amount of substance in urine x urine flow rate
What is the equation for clearance?
Amount in urine x Urine flow rate / Total amount in plasma
Does Creatinine over or under estimate GFR?
Over, since there is slight secretion back into the tubule
What factors affect Creatinine in the body?
Age
Race
Muscle proportion
Protein intake
What is eGFR used for? AKI or CKD?
CKD
Why is isotonic saline used to increased BP?
Increases extracellular fluid volume, but same osmolarity as the intacellular compartment, so no change in osmolarity and so no movement of fluid into the ICF
Where are the low pressure baroreceptors?
Aortic and Pulmonary bodies
Where are the high pressure baroreceptors? What nerves do these pass impulses along?
Aortic arch and carotid body - communicate via CN 9 and 10
Describe pressure natriuresis
When BP increases, NaKATPase downregulated, so more Na passed out, so BP goes down
What AQP is inserted into the apical side of the tubules by ADH?
AQP 2
Name the drug that affects NKCC2 in the Loop of Henle
Furosemide
What is the name of the drug that affects NCC in DCT 1?
Thiazide
What is the name of the drugs that act on ENaC?
Amiloride - blocks the ENaC channels
Spironolactone - downregulation of Aldosterone effect on NaKATPase
What other important anion is absorbed in DCT2 and by what channel? What is its expression controlled by?
NCX channel
Ca2+
Controlled by PTH and Vitamin D
Where does HCO3- excretion occur in the CD?
Intercalated cells (principal cells have the ENaC channels)
What is the normal osmolarity of blood?
275-295mmol/Kg
Describe the body’s response to low BP (4)
- RAAS activation
- Sympathetic innervation increase to heart
- Prostaglandins released
- ADH released
Describe the effects of Angiotensin 2
Causes Aldosterone release
Causes vasoconstriction of arterioles to raise BP
Increases sympathetic activity
Stimulates ADH
Describe the effects of Aldosterone
- Upregulates NaKATPase in DCT
- Stimulates K+ secretion into DCT
- Upregulates NCC in DCT
- Upregulates ENaC
Name 3 ADH-related diseases and their pathophysiology
- Central diabetes insipidus - ADH too low, due to hypothalamus damage/ pituitary damage
- Nephrogenic diabetes insipidus - ADH insensitivity
- SIADH - too much ADH - leads to hyponatraemia
What does SIADH lead to?
Hyponatraemia
How does the Vasa recta work with the counter current mechanism to generate a hyperosmotic interstitium?
Vasa Recta is very hypertonic - passes past the descending limb and absorbs water as it travels up
Explain the role of Urea in the counter current exchange system
Urea is usually an ineffective osmole, but can pass through AQPs with water, increasing the osmolarity of the fluid
List 4 causes of hyponatraemia
Diuretics
Diarrhoea/Vomiting
SIADH
Heart failure - body tries to maintain volume by retaining fluid
What is a risk of giving hypotonic saline too quickly to fix Na balance?
Central Pontine Demyelination Syndrome
What happens to the NaKATPase during acidosis?
Downregulated - means K+ cannot exit, meaning hyperkalaemia even worse
Name 4 causes of Hyperkalaemia
AKI Addison's disease - reduced Aldosterone, reduced secretion Diabetic Ketoacidosis Cell Lysis (injury)
What does Hyperkalaemia cause?
Heart block/arrhythmias - depolarises the heart tissue, leads to more inactive Na+ channels
Also causes paralytic ileus
What is the treatment for hyperkalaemia?
IV Calcium Gluconate
Insulin + Dextrose
Calcium Resonium
What does Hypokalaemia cause?
Arrhythmias - heart more excitable
Paralytic ileus
How do NKCC2 channel blockers (Furosemide) cause Hypokalaemia?
ROMK is not inactivated, but NKCC2 is - K+ moved back into urine
How do NCC channel blockers (Thiazide) cause Hypokalaemia?
NCC block leads to more Na+ downstream, so Renin release and Prostaglandins, leading to aldosterone upregulation (and thus increased NaKATPase, so more Na out and more K+ being secreted/excreted)
How does congestive heart failure lead to Oedema?
Increased venous pressure + RAAS activation, which increases fluid retention
How does Cirrhosis lead to ascites?
Leads to:
- reduced albumin creation, so lower oncotic pressure, so less fluid re-enters the blood vessels
- portal hypertension
What controls storage?
Sympathetic
What levels of the spinal cord control Sympathetic urine storage?
T10-L2
What control voiding?
Parasympathetic
What levels of the spinal cord control Parasympathetic urine storage?
S2-4
What centre in the brain controls storage?
L-centre
What centre in the brain controls voiding?
M-centre supplied by para-central lobules
Describe the storage of urine
Stretch receptors
B3 of detrusor acted on to cause relaxation
A1 of IUS acted on to cause constriction
nAcH of EUS acted on by pudendal nerve to constriction
Describe the voiding of urine
Stretch receptors
M3 of destrusor acted on to cause contraction
Sympathetics inhibited by M centre
What is the boundary of the Cauda Equina?
L2-S5
Why does Cauda Equina lead to incontinence?
S2,3,4 inibited, no para, no voiding ability
Pudendal nerve also lost, so no EUS
Sympathetics still active though
Needs catheterisation
How does an Upper Motor neurone lesion lead to incontinence?
Parasympathetic neurones that are inhibitory will be destroyed
Describe the 3 types of urinary incontinence
Stress - involuntary leakage on exertion
Urge - leaking with sudden urgency
Overflow - overfull bladder
At what volume is urine felt?
150ml
At what volume is urine voided?
500ml
Give 4 causes of Urinary Incontinence
Pregnancy, BPH, Prolapse, Obesity
What is Glomerulosclerosis?
Destroyed glomerular capillaries
What is Glomerulonephritis?
Inflammation of the glomerulus
What is the difference between Primary and Secondary Glomerulonephritis?
Primary = Disease of the Kidney Secondary = Systemic disease
What is Nephrotic syndrome?
Damage to the filter of the glomerulus - podocytes and glomerular basement membrane
- Proteinuria
- Hypoalbuminaemia
- Oedema
What is Nephritic syndrome?
Damage with inflammation
- Haematuria
- Hypertension
- GFR reduction
List 3 causes of Nephrotic syndrome
Minimal change, FSGS, Membranous
Diabetes
List 3 causes of Nephritic syndrome
IgA nephropathy, Anti-GBM, ANCA vasculitis
List 3 treatments for Nephrotic syndrome
Diuretics (for oedema), salt and fluid restriction, steroids, ACE
List 3 treatments for Nephritic syndrome
ACE for hypertension, Diuretics if oedema, immunosuppressants
Describe the effects of diabetic nephropathy
- Hyperfiltration (osmotic diuresis)
- Thickening of the basement membrane
- Mesangial thickening
- Overt proteinuria develops eventually
Leads to ESRD
What is another name for a Lower UTI?
Cystitis
What is another name for an Upper UTI?
Pyelonephritis
Name 3 risk factors for UTIs
Women (shorter urethra), BPH, incontinence (neurological problems leading to incomplete voiding)
What does a fever imply in a UTI?
Upper Urinary tract infection
What are the drugs given for a Lower UTI? How long for complicated vs uncomplicated?
Nitrofurantoin
Trimethoprim
What is the drug given for an Upper UTI (pyelonephritis)?
Co-amoxiclav
What is measured on a urine dipstick?
Nitrites
What is the infective organism in a nitrite negative dip?
Coagulase negative Staph
What are the symptoms of an AKI?
Oliguria, acidosis, oedema, fatigue, nausea and vomiting, ureamia
What is Acute Tubular Necrosis?
Develops from AKI if left for too long - PCT fucked
Name 1 intraluminal causes of Ureteric obstruction
Renal calculi,
Name 1 intramural causes of Ureteric obstruction
TCC
Name 3 extramural causes of Ureteric obstruction
Fibroid, bladder cancer, retroperitoneal fibrosis
What is Pyonephrosis?
Pus build up caused by infection, urological emergency, can get loss of function
What is Hydronephrosis?
Swelling of kidney due to urine build-up
What is a Renal angiogram used for?
Renal artery stenosis
What is a Diuretic urogram used for?
Obstructions
What is the treatment for a ureteric obstruction?
JJ Stent
What is removed in a radical nephrectomy?
Kidney, ureter, peri-renal fat
How is a TCC treated?
Trans-urethral resection of the bladder
What section of the prostate is affected in Prostate Cancer?
Peripheral
What section of the prostate is affected in BPH?
Transitional
Name a gene associated with prostate cancer
BRCA2
Name 2 reasons for an increased PSA value (prostate specific antigen)
Just had a DRE done
Infection
Age increase
How is prostate cancer diagnosed?
Ultrasound guided biopsy of the prostate
What are the cancers that metastasise?
British Transport Keeps People Late Breast Thyroid Kidney Prostate Lung
What is the most common presenting complain for patients with Adult Polycystic Kidney Disease?
Hypertension