Renal Function And Kidney Disease Flashcards
What is the role of the ureter
Transport urine towards bladder
What is the role of the bladder
Temporarily store urine
What is the role of the urethra
Conducts urine to exterior
What is the function of urinary system (3)
- excretion & elimination
- homeostatic regulation
- endocrine function
What is excretion and elimination
- removal of organic waste products from body fluids
Eg, urea, creatinine, uric acid
What is regulated by the urinary system
water - salt balance
Acid - base balance
What is the function of the endocrine
Release hormones into bloodstream
how much urine is excreted daily
1.5l
how much of cardiac output does the renal blood flow contribute to
20%
what is the plasma renal flow
the volume of blood plasma passing through the kidneys per minute
how much is the plasma renal flow
600mL/Min./1.73 M2
What 2 processes does the kidney reflect
- ultrafiltration
- reabsorption
what is the role of the kidney (3)
- homeostasis
- endocrine function
- excretion of waste, drugs, urea
what is homeostasis
maintaining total body contents at a stable and normal level, even during changes in dietary intake or endogenous production rate
what is erythropoietin
a glycoprotein hormone, naturally produced by the peritubular cells of the kidney, that stimulates red blood cell production.
what hormone is produced from the endocrine system that is needed for the kidney function
erythropoietin
what enzyme is produced from the endocrine system that is needed for the kidney function
1-alpha hydroxylase to produce 1,25(OH)2D3
What is paracrine and autocrine function in the endocrine system
Paracrine - cell signalling on nearby cells
Autocrine -signalling acts on the signalling cell
Which elements does the paracrine and autocrine function produce
- bradykinin
- prostaglandin
- endothelial factors
What does bradykinin do
Elevate vascular permeability and to cause vasodilation in some arteries and veins
What does vasodilation mean
When blood vessels widen to allow more blood to flow through
What does the prostaglandin do
Generate inflammatory response
What are the endothelial factors (vasodilators factors)
- nitric oxide
- endothelin
How is the kidney involved in the catabolism (breakdown) of insulin
When the nephron mass decreases, leads to a decreased insulin catabolism and results in longer circulating half life
How can the kidney produce glucose
Via gluconeogenesis during fasting
What will changes in kidney function result in
Change in plasma concentration
How is the kidney involved in blood pressure regulation
- control renin, angiotensin, aldosterone system
- homeostasis in sodium and water
- production of vasodilators substances
Why do sodium and water levels need to be maintained
Maintain normal extracellular fluid volume
What is renal threshold
Concentration in blood beyond which it is excreted in urine
What is the renal threshold of glucose
180mg/dL
What is tubular maximum
Maximum capacity of kidneys to absorb a particular substance
What is the tubular maximum for glucose
350mg/min
What is neutral balance
Dietary intake plus endogenous production equals excretion rate of kidney
What is a positive balance
Intake plus endogenous production > renal excretion
What does a positive balance lead to
Increased total body content
What is a negative balance
Intake plus endogenous production < renal excretion
What does a negative balance lead to
Leading to decreased total body content
What are the key parts of the kidney
Renal cortex
Renal medulla
Renal pelvis
Renal pyramids
Ureter
What are nephrons
They are the functional units of the kidney
They do filtration and reabsorption
Where is the nephron located
Between the cortex and medulla
What 2 parts does the nephron contain
Glomerulus and renal tubule
What is the main function of the glomerulus
Bundle of blood vessels responsible to filtrate the blood
What is the renal tubule
Responsible for absorption or excretion of substances
What does the renal tubule consist of
Bowman’s capsule, proximal tubule, loop of Henley, distal tubule and collecting duct
What are the 2 types of nephrons
Cortical nephrons and juxtamedullary nephron
What percentage of nephrons is cortical
85%
What is the role of the juxtamedullary nephrons
Long loops that go deep into the medulla, important in production of concentrated urine
How many times a day does the kidney filter body’s entire plasma volume
60x
How much oxygen does the kidney consume
20-25%
What are the three phase processes involved in the formation of urine
- glomerulus filtration
- selective and passive reabsorption
- secretion
Where does the glomerular filtration take place
Through the semipermeable walls of the glomerular capillaries
What is the driving hydrostatic pressure provided by
Arterial pressure
What happens during reabsorption
• In the proximal and distal tubule, the primary urine becomes highly concentrated as the result of the removal of water
• At the same time, many other low molecular weight constituents are reabsorbed by active transport – glucose, AA and organic and inorganic ions
What happens during secretion
Released into urine in the kidney by active transport
What is the role of erythropoietin
Controls the differentiation of the bone marrow stem cells. Ensures bone marrow cells are converted to erythrocytes, so concentration in blood increases
What is the role of renin
an enzyme which converts the plasma protein
angiotensinogen to angiotensin I
What is Angiotensin converting enzyme (ACE)
formed in the lungs converts angiotensin I to angiotensin II which causes vasoconstriction and an increase in blood pressure
What is the role of Angiotensin II
stimulates the aldosterone production (water
and sodium retention which together increase blood volume)
What is calcitriol
steroid-related hormone involved in calcium and phosphorus homeostasis
How is renal disease investigated
Personal history and physical examination
Blood laboratory findings
Urinalysis
Assessment of renal function
Imaging
Renal Biopsy
What are plasma labatory findings
• urea, creatinine, Na, K
• Ca, phosphate, parathormone
• pH, HCO3-
• CRP, FW, leucocytosis
• FBC: anaemia
• D dimers
• haptoglobin, myoglobin
• immunology: autoantibodies – ANCA, antiGBM, ANA, antidsDNA, complement
When assessing kidney function what should the urine be
Sterile
• Clear
• Amber colour
• Characteristic odour
• Slightly acidic pH (0.5 and 0.6)
• A specific concentration range
• Specific gravity (1.010 and 1.030)
What amount of urine produced is considered Anuria (dehydration)
<100ml/24hours
What amount of urine produced is considered oliguria
<400L/24 hours
What amount of urine produced is considered healthy
500ml/24 hours
What amount of urine produced is considered polyuria (diuretics, heart failure)
<3L/24 hours
What can red urine suggest
- blood
- beetroot ingestion
- haemoglobin
- myoglobin
What can orange urine suggest
Rifampicin
What can brown urine suggest
Blood, hyperbilirubinemia, nitrofurantoin
What can a urinary test strip (dipstick) show
- specific gravity, pH, blood, albumin, nitrates, glucose, ketones
What can you check with urinary microscopy
Bacteriuria, casts, crystals, phase-contrast
What are the normal values of erythrocytes and leukocytes
> 10 erythrocytes/ul
20 leucocytes/ul
What can glucose indicate in the dipstick testing
Diabetes mellitus
What can urobilinogen (reduced form of bilirubin) indicate in the dipstick testing
Liver function
What can haemoglobin indicate in the dipstick testing
Multiple intravascular haemolysis
What can pH indicate in the dipstick testing
Renal tubular acidosis
What is proteinuria
Renal disease
What is the normal range of protein in urine
> 150 mg of protein /day in adults and > 140 mg/day in children
What is the protein range in someone with proteinuria
300mg/day
