Renal System 1&2 (w22) Flashcards
What is the function of the kidneys ?
The kidneys pressure filter the blood, producing urine.
What are the 3 main functions of the kidney ?
1) filtration of blood
2) reabsorption and secretion
3) HOMEOSTASIS
What is the functional unit of the kidney ?
The nephron
How many L of plasma per day does the kidney process ?
180L plasma/day
What are the 6 main substances filtered and reabsorbed by the kidney ?
1) Water
2) Sodium chloride e.g. reabsorbed to maintain internal O.P
3) glucose
4) Hydrogen ions
5) urea
6) Toxic substances e.g. drug metabolites
What makes up urine in high concentrations ?
- urea
- ureic acid
- creatinine
- K+
- other toxic substances
(Rest is reabsorbed)
What are the two components of the nephron ?
- vascular (blood)
- tubular (filtered fluid)
What are the two sections of the nephron ?
- renal cortex (outer region)
- renal medulla (inner region)
In which direction does blood flow in the kidneys ?
From the afferent arteriole —> to efferent arteriole
What is the proximal convoluted tubule (PCT) responsible for and where is it located ?
- is in the cortex
- responsible for most of the reabsorption/ secretion
What is the loop of henle (LH) responsible for and where is it located ?
- in the cortex
- responsible for osmotic gradient in the medulla
What occurs at the bowman’s capsule (BC) ?
Filtration of the blood, this encloses the glomerulus.
What is the distal convoluted tubule responsible for and where is it located ?
- in the cortex
- responsible for the fine tuning of solute/water re absorption
What are the collecting ducts/ tubules (CD) responsible for and where is it located ?
- on the cortex/medulla
- responsible for the fine-tuning of urine concentration
What are the cells found in the epithelium of the bowman’s capsule and surround the capillaries ?
Podocytes
What are the juxta glomerular cells responsible for ?
For releasing hormones (renin) that control how much water is reabsorbed (fine tuning), can also control filtration rate.
How do the kidneys help with the long term control of blood pressure ?
Via the regulation of H2O and electrolytes
What is the namer of the ball of capillaries in the kidney ?
Glomerulus
What is the name of the tubular structure that surrounds this?
Bowman’s capsule
What is the name of the arteriole that takes blood to the ball of capillaries?
Afferent arteriole
What is the name of the arteriole that takes blood away from this ball of capillaries?
Efferent arteriole
What is the functional unit of the kidney called?
Nephron
What are the different parts of this functional unit?
- CD
- loop of Henle
- PCT
- DCT
How is urine formed ?
- FILTRATION - passive ultrafiltration at the bowman’s capsule
- ACTIVE TRANSPORT (resorption and secretion) - energy driven retrieval of valuable substances along the nephron.
- OSMOSIS (resorption) - mainly in loop of Henley, PCT and collecting duct.
What is the equation of excretion in urine ?
Excreted = Filtered + secreted - reabsorbed
What is the renal corpuscle ?
combination of glomerulus and Bowman’s capsule, and is where filtration takes place
What are the 3 barriers of filtration ?
- Glomerular capillary basement membrane
- Basal lamina/membrane
- Bowmans capsule epithelia (podocytes)
What causes filtration ?
Capillary pressure
What is a hematuria ?
Red blood cells in the urine
What causes damage from outside the kidney ?
- kidney stones, tumours (renal pelvis, ureter, urinary bladder, prostate, urethra)
- UTI (inflammation of urinary bladder, urethra, prostrate)
What causes hematuria from damage inside the kidney ?
- inflammation of the glomeruli (e.g. glomeruli nephritis - affects filtration)
- infarct - necrosis of the kidney
What is proteinuria ?
When there is protein in the urine
Which loop (descending or ascending) is permeable to water ?
The descending loop is permeable to water
Which loop (ascending or descending) is impermeable to water ?
The ascending loop is impermeable to water
What hormone is aldosterone and where is it released from ?
- steroid hormone
- released from adrenal cortex
