Structure and Anatomy of Urinary System Flashcards
What is the urinary system designed to do?
Handle fluids in the body
What does the urinary system enable?
Precise control of the concentration of key substances in the extracellular fluid
How does the urinary system enable precise control of key substances in the ECF?
Through filtration and selective reabsorption
What key substances does the urinary system control?
- Ions
- Small organic molecules
- Water
What is dependant on urinary system control?
Maintaining a stable internal environment
What must the kidney do?
- Control volume
- Control osmolarity
- Help to control pH
- Excrete some waste products
How does the kidney achieve its functions?
By filtering a very large amount of ECF
How many times a day is each litre of ECF filtered?
Over 10
What happens to the filtered ECF?
Nearly everything is recovered (<1% of filtered fluid is excreted)
How much of the water filtered by the kidney is recovered?
>99%
How much of the Na+ and Cl- filtered by the kidney is recovered?
>99%
How much of the hydrogen carbonate filtered by the kidney is recovered?
100%
How much of the glucose and amino acids filtered by the kidney is recovered?
100%
What is not recovered from the fluid filtered by the kidney?
A few waste products, including urea
Give an example of a substance that is actively secreted by the kidney?
H+
Label this diagram of the male urinary system

- A - Right kidney
- B - Ureter
- C - Bladder
- D - Urine
- E - Urethra
- F - Left kidney
- G - Renal tubules
- H - Urine
- I - Renal pelvis
- J - Prostate
- K - Penis
Label this diagram of the female urinary system

- A - Diaphragm
- B - Adrenal gland
- C - Kidney
- D - Renal artery
- E - Renal vein
- F - Inferior vena cava
- G - Abdominal aorta
- H - Ureter
- I - Iliac crest
- J - Psoas major muscle
- K - Uterus
- L - Urinary bladder
- M - Urethra
What kind of organs are the kidneys?
Retroperitoneal
Where do the kidneys sit?
Either side of the spine in the abdominal cavity, roughly at the level of T12-L3. The right kidney usually sits slightly lower than the left
Why does the right kidney usually sit slightly lower than the left?
Because of the position of the liver
How much mobility to the kidneys have on breathing?
~3cm
What gives rise to the kidneys mobility?
Their proximity to the diaphragm
What protects the tops of the kidneys?
The 11th and 12th ribs
Where does the bladder sit?
- Right behind the pubic bone in an adult
- Above the pubic bone in a child
What happens as the bladder fills with urine?
It distends upwards
Where does the prostate sit?
Directly below the bladder
What passes through the prostate?
The urethra
What can happen when the prostate undergoes hypertrophy?
It can prevent urination
Where to the ureters arise from?
The renal pelvis, on the medial aspect of each kidney
What course do the ureters take?
The descend towards the bladder on the front of the psoas major muscle (moving laterally to medially). They cross the pelvis brim near the bifurcation of the iliac arteries (cross anteriorly over the common iliac), under the uterine artery/ductus deferens, and down the pelvic sidewall
Where do the ureters insert?
Into the posterior surface of the bladder
What are the bony landmarks for the course of the ureters?
- Arise at about level of L2
- Descend in front of tips of lumbar spine transverse processes
- Cross into pelvic brim roughly in front of the sarcoiliac joint
- Enter the bladder (vesico-ureteric junction) at the level of the ischial spines
Draw a diagram illustrating the course of the ureters

What is the problem with constricted segments of the ureters?
A kidney stone is likely to cause a blockage
What is the problem with kidney stones causing blockages?
They are very painful
Where are the constricted segments of the ureters?
- The junction of the renal pelvis and the ureter
- The point at which the ureters cross the brim of the pelvis (iliac bifurcation)
- Where the ureters pass into the wall of the urinary bladder
What surrounds the kidney?
A fibrous capsule
What is the outer portion of the kidney?
The renal cortex
What does the renal cortex form?
A continuous smooth outer zone witha number of projections
What are the projections of the renal cortex called?
Cortical columns
Where do cortical columns extend?
Down between the pyramids
What does the renal cortex contain?
- The glomerulus
- Bowman’s capsule
- Renal tubules (except for parts of the loop of Henle)
What takes place in the renal cortex?
Ultrafiltration
What happens to the parts of the loop of Henle that are not in the renal cortex?
They descend into the medulla
What is the renal medulla split into?
Sections known as pyramids
What are the structures in the renal medulla responsible for?
Maintaining the salt and water balance of the blood
What enables the renal medulla to regulate the salt and water balance of the blood?
The renal medulla is hypertonic to the filtrate in the nephron
Give two structures that are in the renal medulla?
- Loop of Henle
- Collecting tubule
What do the pyramids in the renal medulla do?
Empty urine into the minor calyxes
What are the points in which urine enters into the minor calyxes called?
The papilla
What do the minor calyxes surround?
The apex of the renal pyramids
What do the minor calyxes join together to form?
The major calyxes
What happens to urine passing through the calyxes?
It continues to move through the renal pelvis into the ureters
Label this diagram
- A - Cortex
- B - Fibrous capsule
- C - Major calyxes
- D - Renal artery
- E - Renal vein
- F - Renal pelvis
- G - Ureter
- H - Interlobular vein
- I - Interlobular artery
- J - Arcuate artery
- K - Arcuate vein
- L - Medulla (renal pyramids)
- M - Minor calyxes
- N - Renal papilla

What % of the cardiac output do the kidneys recieve?
20%
Where do the renal arteries arise?
From the side of the abdominal aorta at the level of L1/2, immediately below the superior mesenteric artery
What is the result of the position of the aorta and the IVC on the renal arteries?
The right renal artery is longer than the left
What is the most common vascular anomaly?
Supernumerary renal arteries
What is meant by supernumerary renal arteries?
Two or more arteries to a single kidney
What is the occurence of supernumerary renal arteries?
Ranges from 25 to 40% of kidneys
Name the arteries, from renal artery to efferent arteriole
- Renal artery
- Segmental
- Interlobar
- Acuate
- Interlobular
- Afferent
- Arteriole
- Glomerulus
- Efferent arteriole
Label this diagram
Letters are vessels. Numbers are structures.

- A - Renal artery
- B - Segmental artery
- C - Interlobar artery
- D - Arcuate artery
- E - Interlobular artery
- F - Afferent arteriole
- G - Glomerulus
- H - Efferent arteriole
- I - Peritubular capillaries (cortical nephron)
- J - Vaso recta (juxtamedullary nephron)
- K - Interlobular vein
- L - Arcuate vein
- M - Interlobar vein
- N - Renal vein
- Renal cortex
- Renal pyramid
- Fibrous capsule
- Cortical nephron
- Juxtamedullary nephron
- Arcuate vessels
- Interlobular vein
- Nephron loop
- Collecting duct