Urinary System
Purposed to maintain Homeostasis
By controlling composition of blood & blood volume
Indirectly affects blood pH & blood pressure
Purposed to excrete and eliminate waste
Waste from cellular activity
Metabolic wastes (excretes)
Protein metabolism produces toxic compounds
Ammonia
Urea
Uric acid
Urinary organs
Essential system organ
Kidneys
Involved in Storage, Transportation & Elimination
Ureters
Bladder
Urethra
Indirect excretory organs
Skin
Sweating excretes small amounts of urea
Liver
Excretes Bilirubin is excreted in bile and urine
Lungs
Excrete carbon dioxide
Red-brown in color
10~12cm long
5~7 cm wide
~2.5 cm deep
Found T12~L3
Bean shaped
Convex on the lateral side
Concave on the medial side
Hylus for nerves and vessels on concave side
Retroperitoneal
Peritoneum helps hold the kidney in place
Renal Fascia is also in place to help hold the kidney in place
Kidney Features
Renal sinus
Cavity within the kidney
Occupied by the renal pelvis, renal calyces, blood vessels, nerves and fat
Cortex
Granular appearance
Resembles fruit rind
Outer portion of the kidney
Between the renal capsule and the renal medulla
Renal Pelvis
Upper expanded portion of ureter
Point of convergence of two or three major calyces
Renal Medulla
Made of 8~18 renal pyramids
Innermost part of the kidney
Minor Calyx
Duct between renal pyramids & major calyx
Major Calyx
Duct between minor calyx & renal pelvis
Parenchyma is the functional parts of an organ
Kidney parenchyma
Cortex
Medulla
Juxta-: Prefix meaning near, nearby, or close.
Juxtamedullary zone
Space close to the medulla of kidney
Cortical zone
Space close to the cortex of kidney
Nephrons (renal tubules)
Closely packed tubular units
Functional Unit of the kidney
Microscopic
Begins in the cortex
Follows an irregular path (convoluted)
Proximal end has the look a tube pushed back on itself
glomerular capsule (Bowman's capsule)
Glomerulus a capillary tuft that performs the first step in filtering blood to form urine
Glomerular + Glomerulus = Renal Corpuscle
Loop of henle
Portion of the nephron that leads from the proximal tubule
Dips down into the cortex or medulla depending on length
To the distal convoluted tubule
Main function is to create a concentration gradient in the medulla
Circulation of the Kidney
Receives around 20% of the cardiac output
Receives blood from the abdominal aorta
Returns blood to the inferior vena cava
Vasa recta
Long U-shaped vessels arising from the Efferent glomerular arterioles of juxtamedullary nephrons and supplying the renal medulla
The efferent arterioles of the juxtamedullary nephron drain into the vasa recta
peritubular capillaries
The efferent arterioles don't directly drain into the interlobular vein, but rather they go here first
Macula Densa
Monitors filtrate in the ascending loop of henle
Juxtaglomerial cells
cells in the kidney that synthesize, store, and secrete the enzyme rennin
Modified smooth muscles that adjust pressure
Which adjusts volume
Higher pressure yields more volume moved
Ureters
Takes urine from renal pelvis in kidney to urinary bladder
10~12 cm long
Smooth muscle
Peristaltic contractions force urine down
Urinary Bladder
Smooth muscle
Hollow organ
Empty = deflated = in true pelvic cavity
3 openings
2 ureters (1 from each kidney)
1 urethra
Trigone
smooth triangular region of the internal urinary bladder formed by the two ureteral orifices and the internal urethral orifice
urogenital diaphragm
internal sphincter (involuntary)
external sphincter (@ diaphragm & voluntary)
Urethra
Female
Short
male 3 regions
prostatic
passes through prostate gland & ejaculatory duct enters
membraneous
@ urogenital diaphragm
Bulbourethral gland
cavernous
passes through penis
micturition = urination
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