7 urinary tract anatomy

Question 1

Describe the storage and elimination of urine.

Answer 1

Urine drains from renal papillae into minor calyces, then into major calyces, drains into renal pelvis, narrows to become ureter, transported to urinary bladder for storage, and leaves body through urethra.

Question 2

What do the ureters do?

Answer 2

Carry urine from the kidney to the bladder.

Question 3

Where do the ureters begin?

Answer 3

At the renal pelvis of the kidneys.

Question 4

Where do the ureters empty?

Answer 4

Into the posterior portion of the m bladder

Question 5

What are the 3 layers of the ureter wall?

Answer 5

The mucosa, muscularis, and adventitia.

Question 6

Describe the mucosa of the ureters.

Answer 6

consists of transitional epithelium.

Question 7

How is urine transported along the ureters?

Answer 7

Through peristaltic waves.

Question 8

How does urine enter the bladder?

Answer 8

When the peristaltic waves reach the bladder, urine spurts through a fold of mucous membrane and enters the bladder.

Question 9

What are kidney stones composed of?

Answer 9

Uric acid, calcium oxalate, calcium phosphate, or magnesium phosphate.

Question 10

Where do kidney stones form?

Answer 10

In collecting ducts and renal pelvis.

Question 11

How are kidney stones dealt with?

Answer 11

They either pass on their own or can be shattered with sound waves to leave in urine as fragments.

Question 12

What is the ureterorenal reflex?

Answer 12

Constriction of renal arterioles and decreased urine production in the affected kidney.

Question 13

What is the urinary bladder?

Answer 13

A hollow, distensible, muscular organ in the pelvic cavity.

Question 14

What does the bladder do?

Answer 14

Store urine and sends it to the urethra.

Question 15

What are the 4 layers of the bladder?

Answer 15

The inner mucosa, submucosa, muscularis, and outer serous.

Question 16

How much urine can the bladder hold?

Answer 16

1L.

Question 17

At what volume does the bladder experience discomfort?

Answer 17

500ml.

Question 18

How can the bladder extend?

Answer 18

Its wall contains folds, it has transitional epithelium of the inner lining which stretches, and smooth muscle of the bladder wall also stretches.

Question 19

What is micturition?

Answer 19

The expelling of urine from the bladder.

Question 20

What does micturition reflex involve?

Answer 20

Contraction of detrusor muscle and relaxation of the internal urethral sphincter and voluntary relaxation of external urethral sphincter.

Question 21

Describe micturition.

Answer 21

Urine fills the bladder and stimulates stretch receptors, action potential carried to sacral segment of spinal cord via PS nerve, AP stimulates detrusor muscle to contract, causing relaxation of internal urethral sphincter. AP also ascends spinal column to a micturition centre in pons and descending pathways communicate with sacral region of the spinal cord and their effect can be inhibitory or stimulatory.

Question 22

Describe the conscious decision to delay urination.

Answer 22

Signals are sent to inhibit the micturition reflex and then stimulation of somatic motor nerve to external urethral sphincter keeps it closed.

Question 23

Describe the conscious decision to activate urination.

Answer 23

Inhibition of somatic nerve to external urethral sphincter in it opening, signals are sent from the pons to enhance the micturition reflex and detrusor muscle contracts and urine is expelled.

Question 24

What is the urethra?

Answer 24

A tubular organ that conveys urine from the urinary bladder to the outside of the body.

Question 25

Describe the layers of the urethra.

Answer 25

The mucosa, the muscularis, the submucosa which has urethral glands, and the 2 sphincters.

Question 26

Describe the internal urethral sphincter.

Answer 26

Smooth muscle which is involuntary.

Question 27

Describe the external urethral sphincter.

Answer 27

Skeletal muscle which is voluntary.

Question 28

Describe the female urethra.

Answer 28

4cm long and the orifice is anterior to vaginal opening.

Question 29

Describe the male urethra.

Answer 29

19.5cm long, dual function for urination and reproduction, has 3 sections and ends in penis.

Question 30

What are the 3 sections of the male urethra?

Answer 30

Prostatic, membranous, spongy.

Question 31

What does urine composition show?

Answer 31

The volumes of water and solutes that the kidneys must excrete or conserve to maintain homeostasis.

Question 32

Describe the composition of urine.

Answer 32

Consists of 95% water, metabolic waste, small amounts of electrolytes, and trace amounts of amino acids, urochrome to give colour.

Question 33

What is a normal urine output/hour?

Answer 33

50-60ml.

Question 34

What is the typical range of urine volume throughout a day?

Answer 34

0.6 to 2.5L a day.

Question 35

How does urine volume vary?

Answer 35

With fluid intake, body temperature, sweating, environmental factors.

Question 36

What is urea?

Answer 36

A by-product of amino acid catabolism.

Question 37

What does the plasma concentration reflect?

Answer 37

Amount of protein in diet.

Question 38

What is uric acid?

Answer 38

A product of nucleic acid metabolism.

Question 39

How does uric acid enter the renal tubules?

Answer 39

Through glomerular filtration.

Question 40

How is uric acid reabsorbed?

Answer 40

Active transport completely reabsorbs filtered uric acid.

Question 41

What does excess uric acid lead to?

Answer 41

Uric acid precipitating in blood and forming crystals in joints called gout.

Question 42

Which hormones affect solute concentration of urine?

Answer 42

Aldosterone and cardiac natriuretic peptides.

Question 43

What is the kidneys ability to maintain homeostasis dependent on?

Answer 43

Their ability to concentrate urine by reabsorbing large amounts of H2O.

Question 44

What is ADH also known as?

Answer 44

Vasopressin.

Question 45

Describe the distal tubule and CD cells in the absence of ADH.

Answer 45

Impermeable to water.

Question 46

Describe the distal tubule and CD cells in the presence of ADH.

Answer 46

They become permeable and water is reabsorbed by osmosis into the hypertonic medullary interstitial fluid.

Question 47

Describe the urine in presence of ADH.

Answer 47

Very concentrated and low volume.

Question 48

Which nephrons are more important in regulation of H2O reabsorption?

Answer 48

Juxtamedullary.

Question 49

Name 5 factors that contribute to the hypertonic medullary interstitum.

Answer 49

- Countercurrent anatomy of loop of Henle of juxtamedullary nephrons - reabsorption of sodium chloride in ascending limb of LoH - impermeability of water of those ascending limbs - trapping of urea in medulla - hairpin loops of vasa recta minimise washout of hypertonic medulla.

Question 50

What is countercurrent multiplication?

Answer 50

The salty medulla created that allows water reabsorption in the collecting duct.

Question 51

How does concentration change down the medulla?

Answer 51

Filtrate is more dilute at the end than the start.

Question 52

What does ADH do in the membranes of collecting ducts?

Answer 52

Stimulate the insertion of aquaporin channels.

Question 53

Describe changes during life-span.

Answer 53

- Outside of kidneys appear scarred and grainy, due to connective tissue accumulation. -Inside, the nephrons begin to die as early as 20 years (by 80 years, the kidney has lost about a third of their mass). -Loss of glomeruli - loss of surface area for filtration decreases the glomerular filtration rate (begins to decline by 40 years). -Proteinuria may develop. -Renal tubules thicken. -Reabsorption of nutrients and ions becomes less efficient. -Harder for kidneys to clear certain substances. -Blood flow to kidney slows. -Urinary bladder, ureters, and urethra lose elasticity. -Bladder holds less urine. Loss of bladder control may result in incontinence.

Question 54

what does the bladder wall act as

Answer 54

a valve - allows urine to enter and stops the backflow