Urinary System Flashcards
List the four major urinary organs and their functions regarding urine.
- Kidneys (produce urine)
- Ureters (transport)
- Urinary Bladder ( temporarily store)
- Urethra (secrete)
- the rest transport, store, and secrete it
- urinary system is the simplest of the visceral body systems!!!
Explain why the urinary system is often conceptually combined with the reproductive system (uro-genital system)
- the intimate physical relationships of some organs of the urinary and reproductive systems is why the name is combined
State the functions of the urinary system and indicate which one is shared with the cardiovascular and respiratory systems.
- Waste Product Elimination - rids body of urea
* one ounce eliminated each day
* shared with cardiovascular (has waste exchange) - Blood pressure Regulation - produces urine to reduce fluid content of body
- Acid/Base Balance - excrete hydrogen ions and reabsorb bicarbonate ions
* shared with cardio and respiratory systems - Electrolyte Balance - reabsorb Na + in exchange for K+
- Production of Erythropoietin - make RBC’s
- Hydroregulation - regulate water loss
List the two hormones produced by the kidneys can indicate their functions.
- Renin - increases blood pressure
2. Erythropoietin - stimulates RBC production
Roughly sketch a kidney and label its extremities, borders, and hilum.
- Superior Extremity (top)
- Inferior Extremity (bottom)
- Medial Border (concave) - hilum locus
- Lateral Border (convex)
- Renal Hilum
- Posterior Surface (adjacent to diaphragm)
- Anterior Surface - covered by peritoneum
- Pararenal Fat Body
- kidneys hv. retroperitoneum!
List five structures that attach at the renal hilum.
- Renal Artery
- Renal Vein
- Nerve Plexus
- Lymphatic Vessels
- Ureter
Roughly sketch a coronally sectioned kidney and label the renal cortex, medulla, columns, pyramids, minor renal calices, major renal calices, and renal pelvis.
- Each kidney is covered by fibrous capsule of c.t. proper
- Outer Renal Cortex
- Inner Renal Medulla
- Medulla is sectioned into 8-15 Renal Pyramids
- Renal Columns separate the Renal Pyramids
- Hillar Tip of each pyramid = Renal Papilla
- Renal Papilla drains into Minor Renal Calix
- These coalesce to form Major Renal Calices
- These unite to form Renal Pelvis
- This is continuous with the ureter
List the three major components of a nephron and the four sequential subparts of a renal tubule.
Nephron:
- Glomerulus
- Glomerular Capsule
- Renal Tubule
Renal Tubule:
- Proximal Convoluted Tube
- Nephron Loop (3 parts)
- Distal Convoluted Tube
- Renal Collecting Tubule (3 parts)
List the three processes involved in urine formation and indicate which of the three major parts of a nephron are involved in each.
- Filtration (Glomerulus and Internal Wall of Glomerular Capsule)
- Secretion (Renal Tubule)
- Selective Reabsorption (Renal Tubule)
Explain how filtration occurs using the terms glomerulus, internal wall of glomerular capsule, podocyte, pedicel, and filtration slit.
- The Glomerulus receives afferent glomerular arterioles (incoming blood) and drains efferent glomerular arterioles (outgoing blood)
- The Glomerulus is invaginated into the Glomerular Capsule. The Glomerular Capsule has an internal and external wall
- The Internal Wall of the Glomerular Capsule has cells called podocytes
- The podocytes have finger like projections called pedicles that interdigitate with each other and form tiny spaces called filtration slits
- The filtration slits allow passage of water and small molecules from the blood to enter (as blood flows through the glomerulus part of its fluid portion passes through vessel walls into filtration slits)
- It then becomes filtrate once it enters the filtration slit and enters the glomerular capsule
Indicate the name and location of the cells that produce urine.
At one point the distal convoluted tubule is in direct contact with the afferent arterioles of the glomerulus. Cells in this portion interact with the juxtaglomular cells of the afferent arterioles that produce renin.
Name, in order, the vessels through which blood flows in a kidney.
- Renal Artery
* the artery will divide into two major branches (anterior and posterior) - Anterior Branch divides to form 4 segmental branches that supply anterior half of kidney
- Posterior Branch supplies main portion of posterior part of the kidney
- These segmental branches divide to form interlobar arteries
* go into renal columns between the renal pyramids - At the corticomedullary junctions (where cortex and medulla are joined) they form loops called arcuate arteries
- Arcuate arteries supply tiny interlobular arteries
- Afferent arteriole arises as a branch of the interlobular arteries
- The efferent arteriole drains each glomerulus and feeds peritubular capillaries
- They then drain into interlobular veins
- This then leaves kidney through the renal vein
Outline the volumetrics of urine formation beginning with an average resting cardiac output of 5.0 liters/min.
Cardiac Output (C.O.) = 5000 ml/min
Renal Blood Flow (20% of C.O.) = 1000 ml/min
Filtrate formed (10% of renal flow) = 100 ml/min
Filtrate volume reabsorbed (99%) = 99 ml/min
Remaining Filtrate Volume (urine) = 1 ml/min
Discuss how the oblique passage of each ureter through the urinary bladder wall forms a functional valve to help prevent vesicoureteral reflux.
The Ureter transports urine from the renal pelvis to the neck of the urinary bladder.
- the ureter has three major layers
- Mucosa (transitional epithelium/ lamina propria)
- Tunica Muscularis
- Serosa (visceral peritoneum)
- To move urine to urinary bladder, muscularis layer contracts in peristaltic waves
- Ureters penetrate wall of urinary bladder at oblique angles
- This allows increasing pressure of urine in bladder to act as a passive valve to keep terminal portion of ureter squeezed shut
- It remains squeezed shut except when peristaltic waves force more urine into bladder
- This closure prevents back flow of urine from urinary bladder into ureters (vesicoureteral reflux)
* prevents pressure at kidneys leading to renal degeneration
Schematically represent a sagittally sectioned urinary bladder and label the apex, body, neck, fundus, and the internal and external urethral sphincters.
Good to know:
Stretch receptors in bladder wall stimulate the feeling to urinate
- the urinary bladder stores urine until it can be eliminated
1. Apex - superoanteriorly
2. Body - expanded portion
3. Neck - narrowed part that joins urethra
4. Fundus - base of urinary bladder
Layers in Bladder:
- Mucosa
- transitional epithelium (round when bladder empty, flat when full)
- lamina propria
- muscularis mucosae
- Submucosa
- Tunica Muscularis (3 layers)
- detrusor m. = contracts to empty bladder
- internal sphincter m. = smooth m.t. (surrounds urethra)
- external sphincter m. = skeletal m.t. (urethral sphincter m.)
- internal sphincter is unvoluntary control
- external sphincter is voluntary control
- both must be relaxed to urinate
- Serosa
