Lecture 6- urinary tract anatomy

Question 1

storage and elimination of urine

Answer 1

openings in renal papillae- drains into minor calyce= drains into major calyces- drains into renal pelvis- narrows to become ureter- transported to bladder for storage- leaves body through urethra

Question 2

ureters

Answer 2

25cm ong tubes which transport urine from kidney to bladder.

starts at renal pelvis in kidney and empties into posterior portion of bladder in the pelvic cavity

Question 3

ureter wall composition

Answer 3

inner mucous coat
middle muscular coat
outer fibrous coat

Question 4

how does urine move along ureters

Answer 4

via peristaltic waves, frequency of the waves keeps pace with rate of urine formation.
When peristaltic wave reaches the urinzry bladder, irone spurts through a fold of mucous membrane and enters the bladder.
Bladder acts as a valve, preventing back flow.

Question 5

what are kidney stones composed of

Answer 5

uric acid, calcium oxalate, calcium phosphate or magnesium phosphate

Question 6

where do kidney stones form

Answer 6

collecting duct and renal pelvis

Question 7

if kidney stones dont pass from the body on their own, ow can they be removed

Answer 7

shattered with sound waves so fragments can leave in the urine

Question 8

What does kidney stones cause

Answer 8

Strong peristaltic waves in the obstructed iteration to move stone towards bladder
Utererorenal reflex: constricts renal arterioles and decreases urine production in the affected kidney

Question 10

What tends to cause kidney stones

Answer 10

Inherited, especially calcium containing ones

Question 11

Bladder description

Answer 11

Hollow distensible, muscular organ in pelvic cavity which stores urine.
It has a triangular trigone at each of the 3 corners: 2 for ureters one for urethra

Question 12

Walls of bladder

Answer 12

Inner mucous coat
Submucous coat
Muscular coat
Outer serous coat

Question 13

How much can bladder hold

Answer 13

1litre, but discomfort after 500ml

Question 14

How can the bladder extend

Answer 14

Wall contains folds
Transitional epithelial lining allows stretch
Smooth muscle also stretches

Question 15

what is micturition

Answer 15

expelling urine from bladder

Question 16

micturition reflex involves

Answer 16

contraction of detrusor muscle and relaxation of the internal urethral sphincter

Question 17

relaxation of external urethral sphincter is (voluntary/involutary)

Answer 17

voluntary

Question 18

micturition pathway

Answer 18

1. urine fills bladder and stimulates stretch receptors
2. action potentials are carried to the sacral segment of the spinal cord
3. action potentials via parasumpathetic nerves stimulate contraction of detrusor muscle
4. internal urethral spincter relaxes
5. ation potentials ascend yje spinal column to a micturition centre (in the pons)
6. descending pathways communicate with sacral region of spinal cord (effect can be inhibitory or stimulatory)
7. (if concious descision to delay urination is made) signals are sent to inhibit the micturition reflex (3)
8. (if consious descision to activate urination is made) inhibition of somatic nerve to external urethral sphincter results in it opening, signals are sent from the pons to enhance micturition reflex (3) detrusor muscle contracts and urine is expelled.

Question 19

urethra

Answer 19

tubuar organ that passes urine from bladder out of body

Question 20

walls of urethra

Answer 20

inner mucous coat
thick muscular coat
submucous coat- contains many urethral glands

Question 21

sphincters of urethra

Answer 21

internal urethral sphincter: smooth, involuntary
external urethral sphincter: skeletal, voluntary

Question 22

length of urethra

Answer 22

females: 4 cm
male: 19.5 cm , dual functionfor urination and reproduction. has 3 sections- prostatic, membranous, spongy urethra

Question 23

composition of urine

Answer 23

varies due to dietary intake and physical activity, but usally 95% water, contains metabolic waste, electrolytes and urochrome.

Question 24

volume of urine produced per day

Answer 24

0.6-2.5L

Question 25

urea

Answer 25

by prodyct of amino acid catabolism.

Question 26

pkasma conc of urea reflects_____

Answer 26

amount of protein in the diet

Question 27

how does urea enter renal tubules and processes it undergoes.

Answer 27

through glomerular filtration. It undergoes tubular reabsorption and tubular secretion.

Question 28

how much urea is reabsorbed

Answer 28

80%

Question 29

uric acid

Answer 29

product of nucleic acid metabolism

Question 30

how does uric acid enter renal tubules and processes it undergoes

Answer 30

glomerular filtration active transport completely reabsorbs filtered uric acid about 10% enters urine through tubular secretion and is excreted

Question 31

excess uric acid leads to

Answer 31

gout- uric acid precipitates in bood and forms crystals in joints.

Question 32

what hormones affect solute conc of urine

Answer 32

aldosterone and cardiac natriuretic

Question 33

ability of kidneys to have constant internal environment depends on

Answer 33

their abilitu to concentrate urine by reabsorbing large amounts of water

Question 34

DCT and collecting ducts are impermeable to water in the absence of

Answer 34

antidiuretic hormone, resulting in excretion of a high volume of dilute (hypo osmotic) urine

Question 35

ADH also known as

Answer 35

vasopressin

Question 36

which nephrons are most important for regulating water reabsorption

Answer 36

juxtamedullary

Question 37

what factosr contribute to the hypertonic medullary interstitium

Answer 37

1. countercurrent anatomy of loop of henle of juxtamedullary nephrons 2. reabsorption of NaCl in the ascending limb of loop of henle 3. impermeability of water of the ascending limbs of loop of henle 4. trappinf urea in the medulla 5. hairpin loops of vasa recta minimise washout of hypertonic medulla.

Question 38

low ADH VS high

Answer 38

low- h2o passes through high- h2o reabsorbed into hypertonic medullary interstitial fluid

Question 39

antiduiretic hormone

Answer 39

stimulates insertion of aquaporin channels in the apical membrane of the collecting ducts

Question 40

apical membrane

Answer 40

between lumen and collecting duct

Question 41

effect of aging on kidneys

Answer 41

- appear scarred and. grainy due to connective tissue accumulation - nephrons die as early as 20 years -loss of glomeruli so loss of surface area for filtration so GFR decreased (by age 40) - proteinuria may develop - thickening of renal tubules - reabsorption of nutrients of ions less efficient - harder for kidneys to Clear certain substances - lower blood flow to kidneys - bladder,ureters and urethra lose elasticity - can lead to incontinence