Renal

Question 1

what are the components of the renal system

Answer 1

• Kidney
• Ureter
• Urinary bladder
• Urethra

Question 2

what are Renal System Functions

Answer 2

Filtering of blood to produce urine
-	filtration, reabsorption, secretion
Regulation of;
-	blood volume & pressure
-	conc ions & electrolytes
-	red blood cell synthesis
-	via erythropoietin production
Synthesis vitamin D

Question 3

describe the peritoneum

Answer 3

Peritoneum = serous membrane of abdomen
- Many abdominal organs contained within e.g. stomach and liver
Other organs lie against abdominal wall = Retroperitoneal
Only covered by peritoneum on one surface considered behind the peritoneum
- Kidneys & adrenals,
- pancreas, duodenum,
- rectum, bladder,
- ascending & descending colon

Question 4

describe position/location of kidneys

Answer 4

¥ Bean shaped
¥ Size of clenched fist (~130g)
¥ Retroperitoneal
¥ on posterior abdominal wall
¥ either side of vertebral col.
¥ Right kidney slightly lower than left as liver above it
¥ Lumbar vertebrae and rib cage partially protect kidneys
¥ 11th & 12th ribs on L but only 12th on R
¥ Renal fascia = thin layer connective tissue, anchoring kidneys & surrounding adipose to abdominal wall
Pararenal fat - engulfs kidney and acts as cushioning

Question 5

describe External Anatomy of Kidneys

Answer 5

¥ Renal capsule = fibrous connective tissue surrounding each kidney
¥ Hilum = medial side
Ð Renal artery & nerves enter
Ð Renal vein & ureter exit
Ð Opens into renal sinus (cavity filled with fat and loose connective tissue)

Question 6

describe internal anatomy of kidneys

Answer 6

¥ Kidney = cortex + medulla
¥ Cortex: outer area
¥ Medulla: inner area; surrounds renal sinus
¥ Calyces = funnels connecting medulla to renal pelvis
Ð Minor: medulla pyramid extend into funnel of minor calyx; converge to form major calyces
Ð Major: 2-3 per kidney, converge to form renal pelvis
¥ Renal Pelvis: enlarged chamber formed by major calyces, narrows to form ureter
¥ Ureter: exits at the hilum; connects to urinary bladder

Question 7

describe Blood vessels of the kidneys

Answer 7

• Renal blood flow relatively constant despite changes in blood pressure
• Autoregulated by kidneys
• Sympathetic stimulation constricts arterioles
• Set up of BVs within kidneys allows exchange of materials

Question 8

describe arterial supply of kidneys

Answer 8

• Renal arteries from abdominal aorta
• Segmental arteries
• Interlobar arteries ascend toward cortex
• Arcuate arteries arch over pyramid base
• Interlobular arteries project into cortex
Ð give rise to afferent arterioles
Ð Take blood into glomerulus
Ð Efferent arterioles take blood out of glomerulus

Question 9

describe venous supply of kidneys

Answer 9

•	Peritubular capillaries arise from eff art
Ð	Run around convoluted tubules
•	Drain into interlobular veins
•	Arcuate & interlobar veins
•	Renal veins
•	Inferior Vena Cava

Question 10

describe urine production

Answer 10

• Kidneys sort compounds from blood for removal into urine or return to blood
• Carried out by nephrons
1. Filtration – blood pressure forces water & small mols out of glomerular capillaries into Bowman’s capsule = filtrate
2. Tubular Reabsorption – nephron specifically returns some water & useful mols to blood. Remaining water & waste in filtrate = urine
3. Tubular secretion – when nephron selectively transports solutes from blood in peritubular capillaries into filtrate

Question 11

describe The part of circulation involved with urine formation

Answer 11

¥ Afferent arterioles supply blood to glomerulus
¥ Glomerulus capillaries
¥ Efferent arterioles exit the renal corpuscle
Give rise to Peritubular capillaries which form a plexus around the proximal and distal tubules

Question 12

describe Renal corpuscle

Answer 12

¥ Renal corpuscle = Bowman’s capsule + glomerulus
¥ Bowman’s capsule = double walled chamber
¥ Glomerulus = network of capillaries, sitting in capsule
Ð Blood enters glomerulus through afferent arterioles
Ð exits through efferent arterioles
Ð Fluid filtered from blood flows through glomerulus into Bowman capsule
Ð Fluid then flows into proximal convoluted tube
¥ becomes urine!

Question 13

describe Glomerulus Characteristics

Answer 13

¥ Glomerulus capillaries allow blood filtration
¥ Openings in endothelial cells lining capillaries (fenestrations)
- Gaps between cells lining Bowman’s capsule
- Basement membrane between capillary endothelium & Bowman’s capsule = filtration membrane
- 1st step in urine formation when fluid filtered from blood in glomerulus to Bowman’s capsule

Question 14

describe nephrons

Answer 14

¥	Nephron = Functional unit
-	1.3 million per kidney
-	50 mm long
¥	Parts of the nephron:
-	Renal corpuscle (Glomerulus + capsule)
-	proximal tubule
-	loop of Henle
-	distal tubule

Question 15

what happens to urine concentration when you Drink lots of water

Answer 15

kidneys produce lots of dilute urine to eliminate excess without losing too many electrolytes etc

Question 16

what happens to urine concentration when you dont drink enough

Answer 16

kidneys produce small volume concentrated urine

Question 17

describe Urine collecting and expelling structures

Answer 17

¥	Urine flows from nephrons >  papilla > minor calyx > major  calyx > renal pelvis > Ureter >  Bladder > Urethra
¥	Flow in the calyces is slow
Ð	stones ('calculi') can develop
Ð	especially if urine concentration high
Ð	Painful when stones pass into ureter

Question 18

describe the ureter

Answer 18

One for each kidney carrying urine to bladder
Thin tubes, ~25 cm, leave each renal pelvis
Descend retroperitoneal & cross pelvic rim
enter posterolateral corners of bladder
Run medially in posterior bladder wall then open into interior
oblique entry prevents backflow
Three locations where ureter diameter decreases:
Ð ureteropelvic junction
Ð pelvic inlet
Ð bladder
Ð Kidney stones can become lodged here causing sever pain & block passage

Question 19

describe histology of the ureter

Answer 19

Three main layers:
o Mucosa - transitional epithelium, stretches when ureters fill
o Muscularis - smooth muscle contract when urine in ureter
¥ peristaltic waves propel urine to bladder
o Adventitia - fibrous connective tissue with nerves & blood vessels

Question 20

describe the urinary bladder

Answer 20

hollow collapsible muscular sac
Ð empty: bladder lies within pelvis, shaped like upside-down pyramid
Ð full: bladder spherical, extends upward into abdominal cavity
can hold 1L but uncomfortable after 0.5L
Lies on pelvic floor posterior to pubic bones
Males: anterior directly to the rectum
Females: anterior to vagina & uterus
Stores urine & expels it into urethra
Very thick muscle wall – contract expel urine

Question 21

describe the urethra

Answer 21

Transports urine from bladder outside body
Male: about 20 cm long; prostatic, membranous, & penile parts
Female: 3-4 cm long
location of opening & short length why females have more UTIs than males: risk of ascending bacteria from stool contamination
Urethral sphincters control urine flow
Males have internal sphincter which contracts to keep semen entering bladder;
- smooth muscle
Females don’t have this
External sphincter in males & females
skeletal muscle surrounding urethra as extends through the pelvic floor

Question 22

describe control of urination

Answer 22

• Flow of urine from kidneys to bladder relatively constant
• Stretch of urinary bladder by increasing volume urine stimulates micturition reflex
Ð Involves autonomic NS
Ð bladder contracts
Ð urinary sphincters open
Ð Higher brain centres in pons & cerebellum can control micturition reflex
¥ Conscious need to urinate
¥ Develops around 2-3 yrs old
¥ Irritation of bladder/urethra by bacteria can initiate urge to urinate even if bladder almost empty

Question 23

describe urinary incontinence

Answer 23

= inability to hold urine
sphincter function compromised
mostly elderly female persons & pregnancy

Question 24

describe urinary retention

Answer 24

= difficulty of urination e.g. prostatic hyperplasia by elderly males

Question 25

what is Oliguria

Answer 25

low urine output

Question 26

what is anuria

Answer 26

= almost absent urine output

e.g. kidney failure, blocked urine passage, etc

Question 27

describe polycystic kidneys

Answer 27

enlarged kidneys with fluid-filled cysts

causes renal failure, genetic

Question 28

describe bladder cancer

Answer 28

common, good survival if early diagnosis

Smoking major risk factor

Question 29

describe Glomerulonephritis

Answer 29

inflammation of glomeruli, increases permeability of filtration membranes
protein & blood in urine, low blood protein levels and anaemia

Question 30

describe Renal failure

Answer 30

can result from any condition affecting kidney function
Acute – damage to kidneys is rapid & extensive
Chronic – damage to so many nephrons that remaining nephrons cant cope
E.g. trauma to kidneys, tumours, kidney stones, etc

Question 31

what are reasons for use of Urinary Catheters

Answer 31

• obstruction in the tube that carries urine out of the bladder (urethra) – e.g. prostate enlargement
• bladder weaknessor nerve damage
• drain bladder before, after & during surgery
• drainbladder during childbirth especially if you have an epidural
• to deliver medication directly into the bladder e.g. chemotherapy for bladder cancer
• treatment forurinary incontinence