LO 18 Flashcards
List the structures of the urinary system
- Kidneys (2)
- Ureters (2)
- Bladder
- Urethra
Describe the location of the kidneys
- Under 11th rib, just above waistline
- Retroperitoneal - The area in the back of the abdomen behind the peritoneum
- With hands on hips, touch thumbs on backbone – kidney just above thumbs
- Right kidney usually a little lower than left
Describe the internal structure of the kidneys
- Renal Cortex - Outer portion
- Renal Medulla - Inner portion
- Renal Pyramids - Triangular divisions of medulla
- Renal Papilla - Narrow, innermost end of a pyramid
- Renal Pelvis - Expansion of upper end of ureter
- Calyces (major & minor) - Divisions of renal pelvis
The __________ is the basic structural & functional unit of kidneys and comprises the __________ & __________
- Nephron
- Renal corpuscle
- Renal tubule
What is the purpose of the nephron and how many are there per kidney?
- Process/filter blood
- > 1 million/kidney
What 2 structures comprise the renal corpuscle
- Bowman’s capsule
- Glomerulus
Describe the Bowman’s Capsule
- Cup-shaped top of nephron
- Surrounds glomerulus
Describe the Glomerulus
- Network of blood capillaries
- Diameter of shorter afferent arteriole > longer efferent arteriole
- high BP in glomerular capillaries required to filter wastes from blood
List the structures of the renal tubule
- Proximal convoluted tubule
- Loop of Henle/Henle’s loop
- Distal convoluted tubule
- Collecting tubule
Describe the proximal convoluted tubule
- First segment off of Bowman’s capsule
- Proximity is to the glomerulus
Describe the loop of Henle
Straight, desc. limb with a hairpin turn and a straight ascending limb
Describe the distal convoluted tubule
The part of the renal tubule distal to the loop of Henle
Describe the collecting tubule
Straight extesion of the renal tubule
What components of the nephron are in the cortex?
- Renal corpuscle
- Proximal convoluted tubule
- Distal convoluted tubule
What components of the nephron are in the medulla?
- Loop of Henle
- Collecting tubule
Describe the Juxtaglomerular apparatus (JA)
- Located between the afferent arteriole and distal convoluted tubule
- Cells regulate blood volume and blood pressure by secreting renin when blood plasma volume is low
- Renin is released when BP in kidneys is low, it initiates vasoconstriction and increases BP
Describe Erythropoietin
- A hormone produced by specialized cells called interstitial cells found in the peritubular area of the kidney
- Regulates the production & maturation of RBC in the bone marrow
- Chronic kidney problems often lead to anemia
- Link between cardiovascular and urinary system
Describe the flow of urine through the structures of the kidneys
- Collecting tubules
- Pyramids
- Calyx
- Renal pelvis
- Ureter
- Bladder
- Urethra
What are the 3 steps of the formation of urine?
- Filtration
- Reabsorption
- Secretion
Describe filtration of urine
- Continually happening renal corpuscle
- BP from blood flowing through the glomerulus pushes/filters H20 & dissolved substances (filtrate) into Bowman’s capsule into the tubules
- BP affects filtration
- Normal glomerular filtration rate = 125ml/min 🡪180L glomerular filtrate/day
- …but we don’t want to lose everything via filtration….
Describe the reabsorption of urine
- movement of substances out of filtrate/urine into blood direction: renal tubules to peritubular capillaries
- Prevents loss of substances that the body needs
- H20, glucose, other nutrients, Na+, other ions are reabsorbed via active & passive transport mechanisms
- Begins in proximal convoluted tubule, but continues in all renal tubules
- The majority of water from the 180L/day of glomerular filtrate is reabsorbed via osmosis from proximal tubules
Describe the role of glucose in reabsorption
- Active transport: proximal tubules to the peritubular capillary blood
- Diabetes mellitus – excess glucose can’t be reabsorbed, so is excreted (glycosuria)
Describe the role of sodium chloride (salt) in reabsorption
- Na+: actively transported from tubules to blood
- Cl-: passively moves from tubules to blood (attracted by Na+)
Describe the role of potassium in reabsorption
- Filtered at glomerulus and partially reabsorbed in the loop of Henle
- Some secreted in urine
- Consumption of diuretics means more potassium lost in urine