Urinary System (Ch. 27)

Question 1

What does the urinary system include?

Answer 1

Kidneys
Ureters
Bladder
Urethra

Question 2

What are the fxns of the urinary system?

Answer 2

Elimination of nitrogenous wastes and excess ions (storage and excretion of urine)
Maintain ion balance, acid-base (pH balance), regulates blood volume

Question 3

Where are the kidneys located?

Answer 3

Retroperitoneal position (behind vertebrae T12-L 1, 2, or 3)

*Remember, the kidneys are not parallel to each other.

Question 4

What protects the kidneys?

Answer 4

The floating ribs

Question 5

Kidney anatomy

Answer 5

Study kidney drawings. Familiarize yourself with these structures and their locations:
Hilum
Major calyx
Renal cortex
Papilla of pyramid
Renal medulla
Renal pyramid [in renal medulla]
Renal pelvis
Minor calyx
Renal column
Fibrous capsule
Ureter

Question 6

Starting from the outer region, the kidney is surrounded by a ____ ____.

Answer 6

Fibrous capsule

Question 7

In this saggital section, the outer part of the kidney is the ____ and the inner part is the ____.

Answer 7

Cortex; Medulla

Question 8

Beyond the medulla is the ____ ____, which is really just an expansion of the ureter.

Answer 8

Renal Pelvis

Question 9

The ureter will carry the ____ to the bladder.

Answer 9

Filtrate

Question 10

Looking more closely, the medulla has a series of segments called the ____ ____.

Answer 10

Renal Pyramids

Question 11

Each pyramid is separated by a ____ ____ (extension of the cortex).

Answer 11

Renal Column

Question 12

The papilla of the pyramid contain many ____ ____, which drain urine into the ____ ____ located in the renal pelvis.

Answer 12

Urine Tubules; Minor Calices

Question 13

Minor calices drain into larger, ____ ____, which then drain into the ____.

Answer 13

Major Calices; Ureter

Question 14

The ____ is the region where blood vessels and the ureter enter/exit.

Answer 14

Hilum

Question 15

Kidney Blood Supply

Answer 15

Renal arteries branch several times, travel through renal columns to afferent arterioles. The afferent arterioles form a capillary network called the glomerulus. Once blood is filtered, it exits via efferent arterioles.

Efferent arterioles branch into peritubular capillaries surrounding nephron structures.
–termed peritubular capillaries if they surround tubules in cortex

Peritubular capillaries around Loop of Henle are the vasa recta

Drain into interlobar vessels eventually

Question 16

The Nephron

Answer 16

A nephron is the smallest functional unit of the kidney. It’s the actual site of filtration of all of the blood passing through the body. Each renal pyramid contains millions of nephrons.

Question 17

How many quarts blood can a healthy kidney process per hour?

Answer 17

about 8-9 quarts of blood/hour

Question 18

Glomerulus

Answer 18

Capillary bed fed by the afferent arteriole. The walls of the glomerular capillaries are fenestrated - they have slits or pores - and small molecules and water (not RBCs!) are pushed out of the capillaries and into Bowman’s capsule. The fluid is termed filtrate and will be the urine

Question 19

Filtrate vs Blood

Answer 19

Always keep track of whether you’re talking about filtrate or blood. The filtrate is in the tubules. The blood is in vessels.

Question 20

What are the 2 types of nephrons?

Answer 20

Cortical and Juxtamedullary

Question 21

Cortical Nephrons

Answer 21

~85%; found in cortex

Question 22

Juxtamedullary Nephrons

Answer 22

~15%

Very long loops, contribute to ability to concentrate urine and also help conserve water

Question 23

What are the 2 major parts of the nephron?

Answer 23

Renal Corpuscle and Renal Tubules

Question 24

Renal Corpuscle

Answer 24

Glomerulus + Glomerular capsule* = Renal Corpuscle

*Bowman’s capsule aka Glomerular capsule

Question 25

Renal Tubules

Answer 25

Proximal convoluted tubule (closest to renal corpuscle) Loop of Henle (nephron loop): extends down into medulla Distal convoluted tubule Collecting duct (multiple tubules feed into here)

Question 26

Loop of Henle

Answer 26

Has a descending and an ascending limb. These play different roles in the secretion and absorption of ions and fluids

Question 27

Renal Corpuscle: Filtration

Answer 27

Renal corpuscle is designed for filtration: - -glomerulus is a capillary bed - -afferent arterioles bring blood into corpuscle and high pressure pushes the filtrate out through the capillaries and into glomerular capsule. From there it moves into the tubules

Question 28

Corpuscle: Filtration

Answer 28

Blood exits via efferent arteriole Filtrate exits via proximal convoluted tubule Filtrate: water, waste, salt, glucose

Question 29

What comprises the filtrate?

Answer 29

Water, waste, salt, glucose

Question 30

Structure of Renal Tubules

Answer 30

Filtrate enters tubules from renal corpuscle Proximal convoluted tubule: secretory/absorptive (cuboidal epithelial cells) Loop of Henle: --descending limb permeable, simple squamous epithelium --ascending limb impermeable to water Distal convoluted tubule: selectively secretory/absorptive (cuboidal epithelial cells) Exits into collecting ducts

Question 31

Urine Formation: Glomerular Filtration

Answer 31

Movement of substances w/in the glomerulus into the capsular space Occurs in Glomerulus

Question 32

Urine Formation: Tubular Reabsorption

Answer 32

Movement of substances from the tubular fluid back into the blood Occurs in Posterior Convoluted Tubule (PCT) and Nephron Loop

Question 33

Urine Formation: Tubular Secretion

Answer 33

Movement of substances from blood into tubular fluid Occurs in Distal Convoluted Tubule (DCT)

Question 34

One the fluid is in the ____ ____, it is ____.

Answer 34

Collecting Duct; Urine

Question 35

Urinary Tract

Answer 35

Transports urine to outside of body

Question 36

What does the Urinary TRACT include?

Answer 36

Ureters, bladder, urethra

Question 37

Ureter

Answer 37

Urine exits kidneys via ureters Ureters go from kidney to bladder Urine is transported from kidney to bladder by both gravity and peristaltic waves (smooth muscle in ureter wall)

Question 38

Kidney Stones

Answer 38

aka renal calculus Mineral filtering through the kidneys accumulate to form crystals ID'd by location (kidney, ureter, or bladder) or by type (calcium, struvite, uric acid, or other) 80% afflicted are men Extremely painful Related to dehydration, abnormal pH of urine, overstated w/ calcium, uric acid, or oxalate, blockage of urine flow, bacterial infection

Question 39

____% of people afflicted with kidney stones are ____.

Answer 39

80%; Men

Question 40

Urinary Bladder

Answer 40

Muscular sac that stores and expels urine Lies on pelvic floor posterior to pubic symphysis Mucosa (lining) = transitional epithelium + lamina propria Stretches as bladder fills Detrusor muscle (smooth muscle) - contractions squeeze urine from bladder

Question 41

Urethra

Answer 41

Tube lined with smooth muscle/mucosa - drains urine from bladder Thickening of detrusor muscle forms internal urethral sphincter at bladder - urethral junction (involuntary) External urethral sphincter surrounds urethra w/ skeletal muscle sheet, inhibits urine (voluntary) Male urethra longer than female, also carries semen

Question 42

Micturition (urination)

Answer 42

Controlled by brain (pons) When bladder distended (full), stretch receptors send signals to pons Detrusor muscle is stimulated to contract, squeeze out urine. Internal sphincter relaxation involuntary External sphincter relaxation voluntary

Question 43

The urinary bladder can expand to hold up to ____L (liter) of urine.

Answer 43

1 liter

Question 44

Follow a sodium ion from the renal artery to the outside of the body.

Answer 44

1. Renal artery 2. Afferent arteriole (in renal cortex) --> carries blood 3. Glomerulus --> filters blood - -some blood will exit via Efferent Arteriole 4. Nephron - -Proximal Convoluted Tubule (PCT) --> reabsorbs about 65% of nutrients - -Loop of Henle (or Nephron Loop) --> reabsorption of water - -Distal Convoluted Tubule (DCT) --> secretion of potassium and hydrogen 5. Collecting Duct (goes through Medulla) - -water exits out of Collecting Duct 6. Renal Papilla (now urine) 7. Minor Calyx 8. Major Calyx 9. Renal Pelvis 10. Ureter

Question 45

The Proximal Convoluted Tubule reabsorbs about ____% of nutrients.

Answer 45

65%

Question 46

Water exits out of the ____ ____.

Answer 46

Collecting Duct

Question 47

In the Loop of Henle, ____ is reabsorbed.

Answer 47

Water

Question 48

In the Distal Convoluted Tubule, ____ and ____ are secreted.

Answer 48

Potassium; Hydrogen