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MODULE 19: THE URINARY SYSTEM
PART 5 OF 7
Stina’s blood pressure and volume are tracked closely now: as protein and albumin leak, her regulatory hormones are pushed hard — and her old neurogenic bladder, logged in the nervous-system modules, rejoins the urinary story.
Slide 1 Transcript
PATIENT CHART
STINA
THIS PART
Age 51
PRESENTING WITH
Albumin-rich Proteinuria
TESTS ORDERED
Serum EPO, Renal Biopsy, 24-hour urineThe liquid waste excreted by the kidneys. protein
DIAGNOSIS
Renal Amyloid depositionThe process of bone matrix formation by osteoblasts.
CHART CLUES
COLLECTED AS YOU GO
Proteinuria History
Incidental Phlebolith
Albumin-Rich Glomerular Proteinuria
Intact Tubular Function Beside a Glomerular Leak
Neurogenic Bladder Rejoins + the EPO Thread
Biopsy-Confirmed Amyloid in Glomeruli
Renal Amyloid Deposition
Put your money down: We call the kidney a filter — but how does it also set your blood pressure, and where does an old spinal finding fit?
Bet before the control room. The kidney doesn’t just clean blood; over hours to days it decides how much salt and waterThe universal solvent essential for life. the body holds, and therefore your pressureThe force exerted by gases in the respiratory system, affecting airflow and gas exchange.. Commit now: which hormones give the kidney that power — and how does a bladderA muscular organ that stores urine before excretion. problem logged two modules ago in the spinal cordThe central nervous system structure that relays signals between the brain and body. turn out to belong here?
Pick the answer you believe now. We’ll come back to it later!
Not a Drain — a Control Room
The kidney is not just a filter; it is the body’s master regulator of blood volume and pressure. When pressure or sodium(Na⁺): Major ECF cation; important for fluid balance, nerve function. falls, it launches the renin-angiotensin-aldosterone system: reninAn enzyme secreted by the juxtaglomerular cells that helps regulate blood pressure by triggering the sets off a cascade producing angiotensin IIA powerful vasoconstrictor that increases blood pressure and stimulates aldosterone release. — a powerful vasoconstrictor — and aldosteroneA hormone that increases sodium and water reabsorption in the kidneys, helping regulate blood pressu, which drives the distal nephronThe functional unit of the kidney that filters blood and produces urine. to reabsorb more sodium, with water following, raising volume and pressure. A second hormone, ADH from the posterior pituitary, controlsVariables that remain constant to ensure a fair test. how much water the collecting ductA duct in the nephron that collects urine from multiple nephrons and adjusts water reabsorption. reclaims. Through RAAS and ADH the kidney holds the whole cardiovascular system’s volume in balance.
The RAAS Cascade
How the kidney defends pressure — renin to aldosterone.
Slide 2 Transcript
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Drag the Words: Order the RAAS cascade from renin to raised pressure.
ADH and Water
The fine water dial — and why alcohol ‘breaks the seal.’
Slide 3 Transcript
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Single Choice: What does ADH insert into the collecting duct, and with what effect?
The Endocrine Kidney
A filter that’s also a gland — EPO and calcitriolThe active form of vitamin D, promoting calcium absorption in the intestines..
Slide 3 Transcript
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Multiple Choice: Which hormones does the kidney make, and which is the TEMPI ‘E’?
The Road Out
Once urine is made, its path is simple anatomyThe study of the structure of the human body.: from the collecting ducts it drips into the minor and major calyces, pools in the renal pelvisThe central collecting region in the kidney where urine from the calyces enters before moving to the, travels down the ureterThe tube that carries urine from the kidney to the bladder. by peristalsis Rhythmic contractions of smooth muscle that move food through the digestive tract., fills the muscular bladder, and exits through the urethraThe tube that carries urine from the bladder to the outside of the body.. That whole road is lined by stretchy transitional epithelium, and the bladder’s emptying — micturition — is coordinated by the nervous systemThe organ system that controls body functions using electrical and chemical signals., an involuntary sacral reflex under voluntary override.
The Path Out
Collecting duct to urethra — and why a stone is agony.
Slide 4 Transcript
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Fill in the Blanks: Order the path of urine from renal pelvis to urethra.
Under the Microscope
The stretchy urothelium that lines the whole tract.
Slide 5 Transcript
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Mark the Words: Mark the features of transitional epithelium; leave others unmarked.
Stina’s Bladder Rejoins the Story
That last stretch reconnects two threads. Stina already has a neurogenic bladder — the bladder-control problem logged back in the spinal-cord and autonomic modules. Now that we’re standing in the urinary tract proper, her bladder story rejoins the system it was always part of: the same patient, the same body, finally seen whole. (TEMPI watch: the kidney is the source of erythropoietin(EPO): A hormone produced by the kidneys that stimulates erythropoiesis. — the ‘E’ behind her unexplained erythrocytosis from the blood module, a thread that finally comes home here.) With the normal kidney fully built, we’re ready to ask what was breaking it.
Storing and Voiding
A reservoir under reflex and voluntary control.
Slide 6 Transcript
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Summary: Pick the true statement about the micturition reflexA reflex involving the contraction of the bladder and relaxation of the sphincter muscles that leads and the sphincters.
Stina’s Bladder Returns
A spinal finding rejoins the urinary systemThe organ system that removes waste and maintains fluid balance..
Slide 7 Transcript
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Single Choice: Why does Stina’s neurogenic bladder belong to this module too?
FINDING!
Neurogenic Bladder Rejoins + the EPO Thread
Stina’s neurogenic bladder (logged in M9/M11) is now seen as part of the urinary system, and the kidney is confirmed as the source of the erythropoietin behind her unexplained erythrocytosis — the TEMPI ‘E.’ Chart entry: two old threads converging on this organ, one whole-body case coming into focus.
Confirm or refute your bet: We call the kidney a filter — but how does it also set your blood pressure, and where does an old spinal finding fit?
Now that you’ve seen RAAS, ADH, and the path of urine, return to the bet. The kidney sets blood pressure by controlling salt and water, and the same sacral wiring behind Stina’s neurogenic bladder ties it to her spinal injury. Chart entry: master-regulator hormones under strain, and her bladder rejoining one connected case.
Slide 7 Transcript
NEXT PART
Now the case turns. We have the whole normal kidney — so we can finally show exactly what years of untreated SAA did to Stina’s glomerular filter, and why a little protein became a life-threatening leak.
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All pages for Module 19 — The Urinary System
19.0 Module Overview
19.1 A Little Protein in the Urine
19.2 The Kidney from the Outside In
19.3 The Nephron and the Glomerular Filtration Barrier
19.4 Reabsorption, Secretion, and How Urine Is Made
19.5 Master Regulator: Blood Volume, Pressure, and the Path of Urine
19.6 When the Filter Breaks
19.7 Not a Trace, an Alarm
19.8 Conclusion and Assessment
19.9 Evidence Behind the Case
All Modules
- Anatomical Language, Membranes & Homeostasis
- Just Enough Chemistry
- The Cell & Its Transport
- Making Cells & Proteins
- The Integumentary System
- The Skeletal System
- The Muscular System
- Nervous Tissue & the Senses
- The Spinal Cord
- The Brain & the Blood–Brain Barrier
- The Autonomic Nervous System
- Special Senses (in developmentThe process of growth and differentiation.)
- The Endocrine System
- Blood
- The Heart
- Blood Vessels
- The Digestive System
- The Respiratory System
- The Urinary System
- Fluids, Electrolytes & Acid–Base Balance
- The Reproductive System
- The Immune System
List of terms
- urine
- deposition
- water
- pressure
- bladder
- spinal cord
- sodium
- renin
- angiotensin II
- aldosterone
- nephron
- controls
- collecting duct
- calcitriol
- anatomy
- renal pelvis
- ureter
- peristalsis
- urethra
- nervous system
- erythropoietin
- micturition reflex
- urinary system
- development