Kidneys

Question 1

What are the main components of the urinary system

Answer 1

> Kidneys
      v
> ureters
      v
> Bladder
      v
> Urethra

Question 2

What are the main functions of the urinary system

Answer 2

1. Excretion (removal of waste from body fluids)
2. Elimination (discharge of waste as urine)
3. Homeostatic regulation
   - blood volume + pressure (via water content)
   - plasma concentration + ions (calcitriol - calcium levels)
   - blood pH (levels of bicarbonate/H+ ions in blood)
   - conserves nutrients
   - assists liver (detoxify + metabolise amino acids - in starvation)

Question 3

Position of kidneys

Answer 3

> Located posteriorly (either side of T12-L3)
(left kidney is higher a liver pushes right down)
Suprarenal (adrenal) glands at apex
suspended by renal fascia - collagen fibres that hold in place (‘floating kidney’ if damaged)
Well protected
- embedded in thick layer of fat (perinephric fat capsule)
- Strong, outer fibrous capsule

Question 4

Structure of kidney

Answer 4

Outer 
> Renal Cortex
- Cortical columns project between renal pyramids
- Contains the glomeruli
- Where ultrafiltration occurs

Inner
> Renal medulla
- 6-12 triangular structures = renal pyramids (separated by cortical columns)
- tip of renal pyramid = renal papilla - projects into renal sinus
- contains collecting ducts
*renal pyramid + renal cortex around it = renal lobe which is involved in urine product

Collecting ducts > minor calyx
4-5 minor calyx > major calyx
2-3 major calyx > renal pelvis

Question 5

Describe the blood flow to the kidney

Answer 5

Renal artery Renal vein
v ^
Segmental arteries (no segmental veins)
v ^
Interlobar arteries Interlobar veins
v ^
Arcuate arteries Arcuate veins
v ^
Cortical radiate Cortical radiate
(interlobular) arteries (interlobular) veins
v ^
Afferent arterioles Venules
v ^
————————– NEPHRON ———————————-
Glomerulus»>Efferent arteriole»>Peritubular Capillaries
(around nephron)

Question 6

Describe the nephron

Answer 6

> functioning unit of the kidney
- tubular structure within cortex of each renal lobe (~1.25 million per kidney)
- made up of renal tubule + renal corpuscle (contains bowman’s capsule and glomerulus - network of 50 intertwining capillaries)
where filtration occurs

Question 7

Functions of the kidney

Answer 7

A WET BED
> acid - base balance: levels of hydrogen ions/bicarbonate
> water balance
> erythropoiesis: releases erythropoietin - stimulate RBC production to raise O2 levels
> Toxin removal
> Blood pressure balance - releases renin if low sodium levels/low blood volume/high potassium - cascade of reactions to raise blood volume - higher blood pressure
> Electrolyte balance
> Vitamin D activation -via receptors that produce enzymes in presence of vit. D

Question 8

Nephritis

Answer 8

> Inflammation of the kidney
- Interstitial - allergic reaction to meds/ chronically low potassium levels
- Pyelonephritis - Bacterial infection
- Glomerulonephritis - Unknown cause (can be pre-cursor to cancer)
Symptoms
- Pain - pelvic/kidney/abdomen regions
- frequent urination - with blood/pus
- painful urination
- swelling of hands/feet/face
Diagnosis
- Inflammation markers
- raised creatinine/blood urea nitrogen levels
Treatment
- Change meds
- anti-biotics
- short-term dialysis

Question 9

Nephrosis

Answer 9

> Degenerative non-inflammatory disease affecting kidneys
- leaking of blood protein into urine
- Primary - on own (mainly children)
- Secondary - caused by another disorder (diabetes/autoimmune/toxins)
Symptoms
- Swelling of eyes/ankles/feet
- Foamy urine
- Weight gain
- Fatigue
Diagnosis
- Urine/blood test
Treatment
- Meds to reduce bp/thin blood/suppress immune system
- Control causative disorder if Secondary

Question 10

Kidney Cancer

Vascular disorders

Answer 10

> Cancer - generally only discovered in late stage as other kidney is able to compensate

> Vascular disorders
- hardening of arterioles - reduces blood supply - Ischaemia causing tissue death and chronic renal failure
- linked to hypertension + heart failure (blood volume increases so heart has to work harder)
Treatment
- reduce bp
- diuretics

Question 11

Congenital disorders

Answer 11

> Adult polycystic kidney
- gradual development of cysts in both kidneys
Treatment
- surgical removal of cysts or kidney
- meds/dialysis to assist kidney
*In kids - usually fatal as dialysis and transplant = v. difficult

Question 12

Acute renal failure

Answer 12

> Sudden onset in both kidneys
> Due to
- inflammation
- reduced blood flow
- obstruction
- necrosis
> usually reversible - treat primary problem, temporary dialysis

Question 13

Chronic renal failure

Answer 13

> Gradual irreversible destruction of kidney
Causes:
- Chronic kidney disease
- diabetes
- hypertension
3 stages
1. Decreased reserve (60% of nephrons lost)
2. Renal Insufficiency (75%) - increased waste in blood
3. End stage renal failure (90%+) - regular dialysis or transplant is needed
Scar tissue begins to form which causes reduced function and faster degeneration

Question 14

Things to be aware of in physio

Answer 14

> Fistula position - point of dialysis
Exercise tolerance will likely be reduced
Abnormal recovery times
Psychosocial implications - usually lack motivation