❤️Chapter 20- Urinary System

What is the main function of the urinary system?

Filters and removes waste products from blood, including urea and excess salts.

What waste products are commonly processed by the urinary system?

Urea, creatinine, uric acid, and ammonia.

What organs are involved in the urinary system?

2 kidneys, 2 ureters, 1 bladder, 1 urethra.

Where are the kidneys located?

Under the muscles of the back in the retroperitoneal space.

what the Hilum

is the entry and exit point for blood vessels, nerves, and ureters on the kidney's surface.

What are the internal regions of the kidney?

Renal Cortex, renal medulla, renal pyramid, renal papilla, renal pelvis, calyx

Renal Cortex?

outer layer

Renal Medualla?

inner layer

Renal Pyramids

triangle sections in the medulla

Renal Papilla

tip of pyramid- allows urine to flow into the minor calyces before entering the major calyces.

Renal Pelvis

collecting area that leads to ureter and collects urine from the major calyces before it exits the kidney.

Calyx (calyces)

cup-like structures that collect urine from the renal pyramids and funnel it into the renal pelvis. (the plumbing system)

Renal Corpuscle components-

Glomerular capsule & Glomerulus

Glomerular Capsule (bowman Capsule)

surrounds the glomerulus.

Glomerulus

capillary network where filtration begins, also part of circulatory system

What are the components of a nephron?

Renal corpuscle and renal tubule.

Renal Tubule components?

Proximal convoluted tubule, loop of Henle, distal convoluted tubule, collecting duct

What is the role of the proximal convoluted tubule (PCT)?

Reabsorbs most of the filtered nutrients back into the blood.

What is the primary function of the distal convoluted tubule (DCT)?

Further reabsorption of water, sodium, and chloride, and secretion of potassium and hydrogen ions, especially under hormonal control. leads to collecting duct

what is the function of the collecting duct?

plays a crucial role in the final concentration of urine. It facilitates the reabsorption of water and sodium, and can also secrete potassium, contributing to homeostasis and the regulation of blood pressure.

What is the importance of the Loop of Henle?

It helps concentrate urine by creating a medullary salt gradient.

What re the two nephron types?

Cortical nephrons and Juxtamedullary nephrons

Cortical nephrons?

A type of nephron primarily located in the kidney's outer cortex, responsible for filtering blood and forming urine. Makes up 85%

Juxtamedullary Nephrons

A type of nephron located deeper in the kidney, essential for producing concentrated urine and regulating water balance. They play a crucial role in the medullary concentration gradient.

What is the function of the Juxtaglomerular Apparatus (JGA)?

Regulates renal blood flow, glomerular filtration rate, and renin secretion.

What does the kidney’s produce when oxygen is low?

Erythropoietin (EPO), which stimulates red blood cell production.

What does the Juxtaglomerular Apparatus secrete?

Renin & erythropoietin

Steps of Urine formation?

Filtration, Reabsorption, Secretion

Filtration is what?

First stage

This process involves the glomerulus filtering blood, allowing water and small molecules to pass while retaining larger molecules like proteins.

Occurs only in renal corpuscle

The process of removing waste and excess substances from the blood into the Bowman’s capsule in the kidneys.

Reabsorption is what?

Second stage

when failed → glycosuria

99% of filtrate is reabsorbed

The process of reclaiming water, ions, and nutrients from the renal tubule back into the bloodstream, ensuring essential substances are not lost in urine.

Secretion is what?

Third stage

H+, K+, NH4+ and drugs are transported from the blood into the renal tubule, ultimately contributing to urine composition.

Blood → renal tubule

Renal Threshold?

Blood level beyond which the nephron cannot reabsorb all of a substance

Countercurrent mechanisms?

Loop of Henle and surrounding vessels help concentrate urine by making medulla salty (hyperosmotic)

Transport Maximum

Max amount of a substance the nephron can reabsorb. If too much, excess ends up in urine.

Part of Nephron- Glomerulus & Glomerular Capsule

Process in Urine Formation- Filtration

Substance Moved- Water, solutes (Na+, CL- K+), glucose, and other nutrients filter out of blood

Part of Nephron- Proximal Convoluted Tubule (PCT)

Process in Urine Formation- Reabsorption & Secretion

Substance Moved- Water, solutes (glucose, amino acids, Na+), reabsorbed back into the blood; also secrets nitrogenous wastes & drugs

Part of Nephron- Nephron Loop (Loop of Henle)

Process in Urine Formation- Reabsorption

Substance Moved- Water, Na+, and Cl- reabsorbed from the filtrate.

Part of Nephron- Distale Convoluted Tubule & Collecting Duct

Process in Urine Formation- Reabsorption & Secretion

Substance Moved- Water, Na+, Cl-, and other ions are reabsorbed; additional secretion of ammonia, drugs, K+ and H+ occurs.

What is antidiuretic hormone (ADH)?

Posterior Pituitary

A hormone that makes collecting ducts permeable to water, decreasing urine volume (reabsorbs water)

What is Aldosterone?

Adrenal Cortex

stimulates tubules to reabsorb sodium-> water follows

decreases urine volume

What is Atrial Natriuretic Hormone (ANH)?

Heart’s Atrial Wall

Inhibits ADH/ aldosterone → increases sodium and water loss in urine, thereby increasing urine volume.

What is the renin-angiotensin-aldosterone system (RAAS)?

A system that regulates blood pressure and fluid balance when blood pressure or volume drops.

Aldosterone increases Na+/ water reabsorption =?

Increase in blood volume and pressure

Anuria?

No urine Output

polyuria?

excessive urine output often indicative of diabetes or other medical conditions.

pyuria?

pus in the urine

dysuria

painful or difficult urination

Oliguria

Low urine output

What is glycosuria?

The presence of glucose in the urine, often due to failure in reabsorption.

Ureters?

Tubes that carry urine from the kidneys to the bladder.

Urinary Bladder?

Stores Urine

Transitional epithelium

Rugae allow expansion when empty

Urethra?

Carries urine out of the body

Internal sphincter

involuntary smooth muscle

External sphincter

voluntary skeletal muscle

Micturition/ urination are controlled by

Internal and External sphincters

What is urinary retention?

The inability of the bladder to empty, despite urine production.

Treatment for urinary retention?

Urinary catheterization

Improper technique with Urinary Catheterization?

risk for cystitis and urinary tract infections due to bacteria entering the bladder.

Urinary Suppression

Kidneys don’t produce urine

Stress Incontinence?

Laughing, sneezing, or exercise results in involuntary leakage of urine.

Urge Incontinence?

A sudden, intense urge to urinate followed by involuntary leakage of urine, often due to bladder spasms.

Overflow incontinence

bladder does not empty completely, leading to frequent or constant dribbling of urine.

Urinary Retention and Over distended bladder

Men with enlarged prostate gland

Reflex incontinence?

Involuntary leakage of urine occurring without any warning, typically due to neurological conditions that affect bladder control.

nervous system, stoke, parkinsonism, spinal cord injury and multiple sclerosis.

Normal Specific Gravity for urine?

1.005-1.030

Specific Gravity Low?

Renal Disease

Specific Gravity High?

dehydration

Urochrome

yellow pigment from bilirubin metabolism

Proteinuria after exercise?

can be normal

Hydronephrosis?

swelling of a kidney (renal pelvis and calyces) due to a build-up of urine caused by obstruction. It can lead to kidney damage if untreated.

Renal Calculi (Kidney Stones)

• Made of crystallized minerals (e.g., calcium, uric acid).

• Small stones pass in urine; large stones may block flow and need removal

• Can cause renal colic—severe pain due to rhythmic ureter contractions.

Urethritis

Inflammation of the urethra

caused by sti’s like gonnorrhea or chlamydia

Cystitis

• Bladder infection

• Common in women due to shorter urethra

• Causes: Bacteria, stones, tumors

• Symptoms: Pelvic pain, urgency, dysuria (painful urination), hematuria

• Can become ulcerated or spread to kidneys if untreated

Urethral Syndrome (nonbacterial cystitis)

• Most common in young women

• Symptoms: Dysuria, frequency, no bacteria in urine

• Possibly autoimmune, related to lupus

Overactive bladder

• Frequent urination of small amounts

• Involves urgency, dysuria

• Treated with nervous system drugs

Interstitial Cystitis

• Chronic bladder pain without infection

• Treated with bladder irrigation and drugs to expand capacity

Pyelonephritis

Renal Pelvis inflammation usually due to a bacterial infection of the kidneys, often characterized by fever, back pain, and frequent urination.

What is the condition of nephrotic syndrome characterized by?

Proteinuria, hypoalbuminemia, and edema.

What is acute renal failure?

A sudden decrease in kidney function, often treatable.

What are the symptoms of chronic renal failure?

Progressive decline in kidney function leading to uremia.

What happens during secretion in the nephron?

Substances like drugs and certain ions are moved from blood into the urine tubule.

What is the significance of albumin in the blood?

It helps maintain oncotic pressure and keeps water in the vessels.

What can cause hydronephrosis?

Urine buildup due to obstruction from stones, tumors, or structural problems.

What are the effects of aldosterone on urine formation?

Stimulates sodium reabsorption, which also leads to water reabsorption and decreases urine volume.

What is the role of the urethra?

Carries urine out of the body.

How does micturition (urination) occur?

Internal and external sphincters control bladder emptying through a reflex arc.

why is the right kidney lower than the left?

due to liver placement