Ch 26-Urinary System Flashcards
Kidneys
Organs that produce urine
Urinary tract-functions and organs
Organs that eliminate urine-ureters ( paired tubes) urinary bladder (muscular sac), urethra (exit tube)
Micturition
Process of eliminating urine
Homeostatic functions of the urinary system (5)
- Regulates blood volume and blood pressure
- Regulates plasma ion concentrations
- Helps stabilize blood ph
- Conserves valuable nutrients
- Assists liver
Kidney position maintained by….
Overlying peritoneum, contact with adjacent visceral organs, supportive connective tissues
Each kidney protected and stabilized by these 3 connective tissue layers…
- Fibrous capsule, layer of collagen fibers, covers outer surface of entire organ
- Perinephric fat, thick layer of adipose tissue, surrounds renal capsule
- Renal fascia, dense fibrous outer layer, anchors kidney to surrounding structures
Sectional anatomy of kidneys
Renal sinus, renal cortex, renal pyramids, renal columns
Kidney lobe consists of:
Renal pyramid, overlying area of renal cortex, adjacent tissues of renal columns
Blood flow through the kidneys
IN…
- Renal artery
- Segmental artery
- Interlobar artery
- Arcuate artery
- Interlobular artery
- Afferent arteriole
- Glomerular capillaries
- Efferent arteriole
- Peritubular capillaries (gas and fluid exchange occurs)
- Interlobular vein
- Arcuate vein
- Interlobar vein
- Renal vein…OUT
3 Functions of Urinary System
- Excretion
- Elimination
- Homeostatic regulation
Renal papilla
Ducts discharge urine into minor calyx, a cup-shaped drain
Major calyx
Formed by four or five minor calyces
Renal pelvis
Large, funnel-shaped chamber, consists of two or three major calyces, fills most of renal sinus, connected to ureter
Sympathetic Innervation
Adjusts rate of urine formation by changing blood flow and blood pressure at nephron
Stimulates release of renin
Release of renin
Restricts losses of water and salt in urine by stimulating re-absorption at nephron
Renal tubule
Long tubular passageway, begins at renal corpuscle
Renal corpuscle
Spherical structure consisting of: glomerular capsule, cup-shaped chamber, capillary network (glomerulus)
Filtration
Occurs in renal corpuscle
Blood pressure forces water and dissolved solutes out of glomerular capillaries into capsular space
Produces protein-free solution (filtrate) similar to blood plasma
3 Functions of Renal Tubule
- Reabsorb useful organic nutrients that enter filtrate
- Reabsorb more than 90% of water in filtrate
- Secrete waste products that failed to enter renal corpuscle through filtration at glomerulus
Segments of Renal Tubule
Located in cortex-PCT (proximal convoluted tubule), DCT (distal convoluted tubule), separated by nephron loop (loop of Henle)
Organization of Nephron
Traveling along tubule, filtrate gradually changes composition
Changes vary with activities in each segment of nephron
Each nephron empties into the__________
collecting system-a series of tubules that carries tubular fluid away from nephron
Collecting ducts
Receive fluid from many nephrons, Each duct begins in cortex, descends into medulla, carries fluid to papillary duct that drains into a minor calyx
Renal corpuscle function
Filtration, pressure forces water and solutes out of capillaries into capsular space, filtrate enters renal tubule where nutrients get reabsorbed
Visceral epithelium
Consists of large cells (podocytes) with complex processes or “feet” (pedicels) that wrap around specialized dense layer of glomerular capillaries
Filtration slits
Narrow gaps between adjacent pedicels, materials must be small enough to fit through these
Blood flow control
Special supporting cells (mesangial cells) between adjacent capillaries, control diameter and rate of capillary flow
Filtration membrane consists of…
Fenestrated endothelium, Dense layer, Filtration slits
Filtration at renal corpuscle
Is passive
Solutes enter capsular space-metabolic wastes and excess ions, glucose, free fatty acids, amino acids, vitamins