Urinary System Flashcards
Function of kidney.
Filters blood; byproduct = urine
Function of ureter.
Transports blood filtrate byproduct (urine) from kidney to bladder.
Function of urinary bladder.
Stores urine.
Function of urethra.
Excretes urine to external environment.
Functions of urinary system (4).
- regulate blood volume + ionic composition
- regulate blood pH (excrete H+)
- regulate BP (H20 loss, secretes renin)
- excretes nitrogenous waste, toxins, drugs
Why is urine acidic?
H+ ions are a byproduct of metabolic activity - high release of H+ free floating within blood –> excreted thru urine
Why do our bodies have nitrogenous waste?
Breakdown of protein products into constituent components (i.e. amino acids)
Where are the kidneys located?
- retroperitoneal space
- Left: T12 - L2
- Right: L1 - L3 (b/c liver)
What are the 3 layers [of fat] surrounding the kidney (in closest contact to kidney outwards)?
- perirenal fat
- renal fascia
- pararenal fat
T/F
The renal fascia extends between the kidney and suprarenal gland.
True.
This allows us to remove a kidney w/o disturbing the adrenal gland.
T/F
The renal fascia remains open down towards the pelvic cavity.
True.
The renal fascia does not surround the base of the kidney. Therefore, any tumour growth can move inferior into the pelvic cavity.
What is the function of the renal papilla (inside the kidney)?
At apex of pyramid - collecting ducts found within the pyramid where the urine that is produced is conducted down into the central holding space (calyx).
What is the function of the calyx? What is it attached to?
- holding area for urine which then drains into renal pelvis
- attached to renal papilla and renal pelvis (where urine exits kidney)
Renal arteries branch into 5 _________ arteries, which further divide into _______ arteries (lie in b/n the lobes). The latter sends a branch along the base of the pyramid known as _______ arteries.
- segmental arteries (5)
- interlobular arteries (b/n lobes)
- arcuate arteries (wrap around pyramids)
**Note: interlobular and arcuate arteries do NOT connect - there is a break in the artery, NOT continuous
What is is the function of the renal corpuscle?
Part of nephron (functional unit) which lies within the lobule; feeds off blood from afferent arterioles
T/F
The number of nephrons in a lobule are dependent on the number of afferent arterioles within the lobule.
True.
Several hundred will exist within any given space.
T/F
You can lose about 90% of nephrons and still have a kidney that functions.
True.
- approx 1 million nephrons/ kidney
What is the function of the renal corpuscle?
Produces filtrate from blood to filter within the nephron
What is the function of the proximal convoluted tubule?
ABSORBS water, ions, organic nutrients
What is the function of the Loop of Henle aka nephron loop?
descending - further reabsorption of H2O
ascending - reabsorption of Na+ and Cl-
What is the function of the distal convoluted tubule?
- Secretion of ions, acid, toxins
- Variable reabsorption of H2O, ions
- **controlled by ALDOSTERONE
What is the function of the collecting tubule?
- makes up renal pyramids
- Variable reabsorption of H2O, ions (sodium, potassium, hydrogen, bicarbonate)
- **controlled by ADH (helps you RETAIN H2O-affects permeability of ducts/tubules)
Function of the nephron
- filter blood in renal corpuscle: blood cells, large proteins cannot pass
- small proteins, ions, metabolites, dissolved weights pass
- water, ions, etc reabsorbed (selectively brought back)
2 types of nephrons:
- cortical - 75-80% (mostly in cortex)
- juxtamedullary - 20-25%
(along border of cortex/ medulla; very LONG loop of Henle [imp for urine concentration])
How many filtration layers do glomerulars have within the Bowman’s capsule? Describe each layer.
Three. From endothelial side:
1) fenestration pore of glomerular - prevents passage of blood cells
2) basal lamina - prevents passage of larger proteins
3) slit membrane b/n pedicels (finger-like projections of podocyte) - prevents filtration of medium-sized proteins
The bed of capillaries within a renal corpuscle is known as a ________.
Glomerulus
The renal corpuscle has ___ layers of tissue.
Two.
1) Bowman’s capsule itself (parietal layer)
2) Podocyte (visceral layer)
The space b/n the parietal and visceral layer within the renal corpuscle is called _______.
Bowman’s space - filled w/ filtrate (components of blood squeezed out b/n podocytes).
Where does the filtrate drain into once in the Bowman’s space?
Enters the proximal convoluted tubule (picture: nephron).
What is the visceral layer of tissue within the renal corpuscle called? What is its function?
PODOCYTE.
- surrounds glomerular capillaries
- “foot processes” will interdigitate w/ another podocyte to create slits: used as filter
What is the name of the “foot processes” that extend from the podocyte, wrapping itself around the glomerular capillaries?
Pedicel
What is the function of the papillary duct?
- Delivery of urine to calyces
What are the structural differences b/n proximal vs distal convoluted tubules?
Proximal: has microvilli, larger lumen
Distal: smaller lumen, no villi, less compacted cells
Which region of the nephron is controlled by aldosterone?
Distal convoluted tubule (secretion, some reabsorption)
- controls composition of material present in blood
Which region of the nephron is controlled by ADH?
Collecting ducts + tubules
- variable reabsorption of H2O, ions
What exists within the space of the nephron to affect urine [filtrate] concentration?
Salt gradient (along entire medulla - increase probability of drawing more water into interstitial tissue). Highest concentration in loop of Henle, collecting tubule.
What is distinctive about the cortical nephron’s blood supply?
Efferent arteriole forms capillary bed around tubules (disorganized system of vasculature).
What is special about the juxtamedullary nephron’s blood supply?
- “vasa recta” travels straight down along w/ loop of Henle
- carries away H2O to preserve salt gradient
What are the cells in contact with the arterioles within the juxtaglomerular apparatus - monitor electrolyte concentration?
Macula densa (dense, compact)
What is the function of JGA cells?
- influenced by macula densa
- controls diameter of afferent (in) arteriole
- secrete renin (elevates BP)
= affects BP and volume into glomerulus
What is the name of the smooth muscle that makes up the bladder?
Detrusor muscle (contains rugae [folds] on endothelium to allow capacity to expand)
What kind of epithelium does the bladder have along its lumen?
Transitional epithelium (needs to accommodate stretch)
What kind of epithelium does the urethra have along its lumen?
Stratified squamous epithelium (like skin - will be sloughing off surface lining as acidic urine is released)
What kind of muscle is the urethra mainly composed of?
Smooth muscle.
Where do are mucous glands found within the urethra? What is their main function?
In lamina propria - maintains moisture within urethra, provides physical barrier for anything crawling up urethra.
What kind of epithelium does the ureter have along its lumen?
Transitional epithelium (thicker - can have a fair amount of distention)
What is the function of the smooth muscle around the ureter?
Squeezes from top (by renal pelvis) to ureter
What is the passage of the uretic tube from the kidney to the bladder?
Travels behind most of the blood vessels until passing iliac vessels anteriorly, attaching to posterior side of bladder.
In renal vessels, does the artery or vein run deeper within the body?
Renal artery.
Think: ART = deep
The inferior vena cava runs more towards the right side of the body. What are the effects of this placement?
Right renal vein is shorter than the left.
What two veins drain into the left renal vein? Why is this important?
- left gonadal vein
- left suprarenal vein
- -> need to ligate veins during removal of kidneys
The abdominal aorta sits more towards the left side of the body. What are the effects of this placement?
Left renal artery is shorter than the right.
Name the 3 sites of ureteric constriction.
1) utereropelvic junction (kidney meets ureter)
2) crossing iliac vessels
3) ureterovesical junction (ureter meets bladder)
Where do kidney stones begin developing?
Within the minor/ major calyces of the kidney –> passes into the ureteric tubes (squeezed by peristaltic waves downwards)
What are the kidneys and ureters innervated by?
autonomic nervous system (T10 - L1/2)
Why does pain from kidney stones start from the back?
Kidneys located on posterior side of peritoneum (T10). As it travels down the ureter, the pain goes lower, coming anterior as it passes iliac vessels into bladder > urethra > felt in genital/ groin area (L1-2)
