Urinary Flashcards

1
Q

Functions of the urinary system

A

⭐️ excretion of unwanted substances
⭐️maintenance of water & electrolyte balance
⭐️ pH regulation of body fluids (especially blood)
⭐️ production of hormones (erythropoietin & calcitrol)
⭐️ regulation of RBC production
⭐️ regulation of blood pressure, volume & osmolarity
⭐️ regulation of blood glucose levels

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2
Q

What compound does the kidneys specialise in excreting

A

Nitrogenous wastes
(Amino acid/protein building blocks of nitrogen)

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3
Q

What wastes and toxins do the kidneys excrete

A
  1. Urea - metabolite of protein metabolism
  2. Uric acid - purine metabolism product
  3. Creatinine - muscle metabolism product
  4. Hydrogen ions - excess acidity
  5. Medications & toxins - detoxed in the liver
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4
Q

What is the minimum urine content required to clear body waste

A

500ml/day

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5
Q

What are the most important electrolytes regulated by the kidneys

A

Sodium, potassium & hydrogen

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6
Q

What are buffer substances

A

Molecules that can buffer/regulate changes in pH
By conjugation

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7
Q

What are the two primary pH control systems

A

Lungs - excrete co2
Kidneys - excrete hydrogen & produce buffer bicarbonate

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8
Q

What is calcitriols role with the kidneys

A

UV light triggers vitamin D precursor in skin
Kidneys converts to calcitriol
This increases bone formation (calcium absorption) & reduces calcium loss in kidneys (along with PTH)

Deficiency can cause osteomalacia and rickets

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9
Q

What are normal blood glucose ranges

A

4-7 mmol/L
Above 9 inidcatez pathology eg diabetes mellitus

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10
Q

What process do kidneys undergo to make glucose when hypoglycaemic

A

Make glucose from the amino acid GLUTAMINE
- gluconeogenesis

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11
Q

How do the kidneys maintain a constant blood concentration/osmolality

A

Conserve/eliminate water
Regulat loss of solute

Regulate blood pressure by secreting enzyme RENIN to acitivate Renin-Angiotensin-Aldosterone pathway

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12
Q

Where are the kidneys located

A

Partially protected by the 11th & 12th pairs of ribs (between vertebrae T11-L3)

Right kidney is lower than left because liver occupies space on right side superior

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13
Q

What layers surround the kidneys

A

1) renal capsule (deep layer) - connective tissue

2) adipose capsule (middle layer) - protection & support

3) renal fascia (superficial layer) - connective tissue that anchors kidneys in place

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14
Q

What is the renal papilla

A

The point of the renal medulla pyramids where urine collects to enter the ureter

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15
Q

What is the renal hilum

A

The region where blood vessels, lymph vessels, nerves & ureters enter & exit the kidney
Kidneys receive 20-25% cardiac output

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16
Q

What is a kidney nephron

A

Functional unit of the kidney
More than 1 million per kidney
Single epithelial layer

Layers:
1) renal corpuscle
2) renal tubule

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17
Q

What is the glomerulus

A

A tangled capillary network that receives blood from an afferent arteriole in the kidney

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18
Q

What is the bowmans capsule

A

A double walled epithelial cup that surrounds the glomerulus, receiving contents of filtered blood

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19
Q

What is the renal tubule

A

Filtered fluid is passed through the tubule and is important in reabsorption & secretion of various solutes

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20
Q

How does ADH act on the kidneys

A

Acts on the distal convoluted tubule to reabsorb water

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21
Q

What is the loop of henle

A

Loop in the renal tubule that descends & ascends

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22
Q

Function of the 2 URETERS

A

Peristaltic contractions of their muscle walls propel urine down down into bladder

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23
Q

Why do ureters have a mucous membrane

A

Assists in reducing friction & allows easy movement as well as a protective layer from urine

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24
Q

What is transitional epithelium & where found

A

Epithelium with ability to strectch

Found in the bladder !

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25
Q

What is the trigone

A

Located on posterior floor of bladder, small triangular shape bordered by the two ureteral openings & the urethral opening

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26
Q

What is the detrusor

A

The smooth muscle found in the muscularis layer of the bladder

The fibres accumulate & form the internal urethral sphincter

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27
Q

What is the urethra

A

Tube leading from the bladder to the exteroir of the body, passageway for urine & in males semen too

28
Q

What are the 3 basic processes of urine formation

A
  1. Glomerular filtration
  2. Tubular reabsorption
  3. Tubular secretion
29
Q

What molecules can pass through the glomerulus

A

Water & small molecules can pass through the pores in the glomerular capillaries
Mineral salts (electrolytes)
Amino acids & glucose
Ketoacids
Hormones
Creatinine
Urea
Uric acid
Toxins

30
Q

How is glomerular filtration adapted

A
  1. The diameter of the efferent arteriole (ie enters at high pressure) is less than that of the afferent
  2. 50x more leaky than normal capillaries
31
Q

What molecules cant pass through glomerular filtration pores

A

Leukocytes
Erythrocytes
Platelets
Plasma proteins

32
Q

What 3 main filtration pressures do glomerulus depend on?

A
  1. Blood pressure in the glomerular capillaries force substances through
  2. Proteins present in blood plasma maintain osmotic pressure & oppose blood pressure
    “Blood colloid osmotic pressure”
  3. Back pressure of fluid already passed through in the tubule opposes filtration
    “Capsular hydrostatic pressure”
33
Q

What is the glomerular filtration rate (GFR)

A

The amount of filtrate formed in the renal corpuscles of both kidneys each minute

Males = 125ml/min
Females = 105ml/min

Normal should be over 90ml/min
Calculated through a blood test helps determine kidney disease
Anything affecting 3 filtration pressures will affect GFR

34
Q

What is colloid osmotic pressure

A

A form of osmotic pressure exerted by proteins (notably albumin)

35
Q

What can damage of the glomerular capillaries lead to

A

Can lead to plasma protein loss into urine, specifically albuminuria

Less albumin in blood makes it hypotonic, fluid moves from blood into tissues
Decreases blood volume & interstitial fluid volume increases leading to oedema

36
Q

What is most commonly reabsored into the bloodstream in the renal tubules & collecting ducts

A

Water (65% in PCT)
Amino acids & glucose
Electrolytes

Most reabsorption occurs in the proximal convoluted tubule

37
Q

What does angiotensin mean

A

Angio = vessel
Tensin = constriction

2 Triggers vasoconstriction which increases blood pressure & triggers pituitary release of ADH & adrenal cortex to produce aldosterone

38
Q

What 5 hormones affect kidney reabsorption of sodium, chloride, calcium, water & potassium secretion

A
  1. Angiotensin II
  2. Aldosterone
  3. ADH
    — all 3 increase blood pressure
  4. Atrial Natriuretic peptide
    — works to lower blood pressure
  5. Parathyroid hormone
    — elevates blood calcium lvls
39
Q

What is the overall effect of the ‘RAAS’ system

A

Increases blood pressure

Angiontensin II = vasoconstriction
Aldosterone = water reabsorption in kidneys

40
Q

What are the effects of Atrial Natriuretic Peptide

A

Inhibits reabsorption of sodium & water in the renal tubules

ANP is released in response to atrial stretch, reducing blood volume and increasing urine output hence lowering blood pressure

Also suppresses release of ADH & aldosterone

41
Q

How does PTH increase blood calcium

A

Stimulates renal reabsorption of calcium & magnesium
Increases osteoclast activity
Stimulates calcitriol release (increasing gut calcium absorption)

42
Q

What does micturition mean

A

The discharge of urine from the bladder

43
Q

What is the micturition reflex

A

When volume in bladder exceeds 200-400ml stretch receptors in bladder wall transmit nerve impulses to spinal cord at levels s2 & s3

Generating a micturition reflex, relaxing internal urethral sphincter (& external in infants)

44
Q

What are the usual compounds found in urine

A

Water (96%)
Urea (2%) uric acid & creatinine
Ammonia
Na, K, Cl, P, S
Hormones
Oxalates (found in fruit & veg)

45
Q

What signs & symptoms need to be looked out for indicating urinary system pathology

A

Frequent & painful urination with urgency
Red urine (blood or foods?)
Pain in the loin
High urine volume with great thirst
Low or no urine volune
Nausea & vomiting
Oedema
Exhaustion

46
Q

Common signs of renal disease

A
  • pallor (due to anaemia)
  • frothy urine (proteinuria)
  • oedema
  • signs of itching skin (uraemia)
  • altered mental state (common with UTIs)
  • puffy face & bags under eyes
  • dehydration (slow skin recoil) & flapping tremor (shaking wrists when extended)
47
Q

main types of urine analysis

A
  1. Dipstick test
  2. Urine microscopy
  3. Blood test - GFR, Urea, creatinine, electrolytes
  4. Ultrasound, cystoscopy, MRI, CT
  5. Inflammatory markers
48
Q

What are casts

A

Groups of cellular materials that clump together in kidney nephrons

49
Q

Dysuria

A

Painful, burning urination

50
Q

Oliguria & polyuria

A

Polyuria = large quantity of urine
Oliguria = little urine (<400ml/day)

51
Q

Anuria

A

No urine

52
Q

Nocturia

A

Night urination - waking to urinate

53
Q

Why can increased glomerular permeability lead to oedema

A

Loss of plasma proteins leads to low plasma osmotic pressure, so fluid moves out of capillaries into tissues = oedema

54
Q

What are the use of diuretics

A

Meds which increase loss of sodium & water from kidneys
Reduce reabsorption from kidney tubules
Used for oedema & hypertension

55
Q

Common bacterial cause of cystitis

A

E.coli

56
Q

What is glomerulonephritis

A

Immune mediated disease that causes glomerular inflammation

Autoimmune reaction (type III hypersensitivity) where antigen-antibody immune complexes are formed in response to infection. These are deposited in the glomeruli where they trigger immune response, causing leaky capillaries & leukocyte proliferation allowing proteins & erythrocytes to escape into urine

Immune mediated can occur 1-3 weeks after bacterial infection (often from upper respiratory tract) eg children can develop post-streptococcal glomerulonephritis

57
Q

What is nephrotic syndrome

A

A collection of signs & symptoms associated with increased glomerular permeability & heavy proteinuria

Not a cause but a syndrome Eg lupus can be cause

58
Q

Why are you more likely to develop kidney disease when diabetic

A

Diabetes mellitus elevates blood pressure
Glomerulosclerosis occurs as a result of increased intra-glomerular pressure
Kidenys are often enlarged
Glomeruli often become damaged & proteins leak leading to associated syndrome

59
Q

What are renal calculi usually made of

A

80% calcium oxalate & phosphate

60
Q

What is haemodialysis

A

Used in cases of renal failure, blood is taken through a machine whereby mimicing excretory function of kidneys to remove wastes/balance electrolytes etc

61
Q

What is peritoneal dailysis

A

Same case as mimicing kidney functions in states of renal failure but envolving extraction through the peritoneum itself, utilising the highly vascular semi-permeable membrane to allow for diffusion of fluids & dissolves substances

Tube inserted into abdomen which administers dialysis fluid, through which waste products diffuse into, removal occurs via a shunt & changing dialysis solution when in excess

62
Q

What is the renal threshold for glucose

A

9mmol/L

63
Q

What is a metabolic waste excreted by kidneys

A

Uric acid

64
Q

What forms the renal corpuscle

A

The glomerulus & bowmans capsule

65
Q

What hormones are produced by the kidneys

A

Erythropoietin & calcitriol (converts vitamin D inactive form to active)