Case 3- renal anatomy

Question 1

Glomerulus

Answer 1

Where the blood is filtered to produce urine

Question 2

Bowman’s capsule

Answer 2

Collection of glomerular filtrate

Question 3

What’s absorbed in the Proximal tubules

Answer 3

Reabsorption of water, proteins, amino acids, glucose and carbohydrates

Question 4

Loop of Henle

Answer 4

Creates Hypertonicity gradient (osmotic pressure) between the collecting duct and interstitium

Question 5

Distal tubule- role

Answer 5

Controls pH and water balance. Absorption of water, Na+ and HCO3-. Excretion of K+ and H+

Question 6

Collecting duct

Answer 6

Controlled reabsorption of water under the influence of ADH

Question 7

Where are the nephrons locates

Answer 7

In the cortex or medulla, some cross both

Question 8

Mesangium

Answer 8

Between the capillaries of the glomerulus, it provides support for the capillaries

Question 9

Structure of Mesangium

Answer 9

Podocytes- interlocking foot like processes, provide epithelial lining for bowman’s capsule
Basement membrane- between the podocytes and fenestrated epithelium. Layers from outside in are the Lamina rara externa, the Lamina densa and the Lamina rara interna.
Fenestrated epithelium

Question 10

Layers of the medulla

Answer 10

Outer and inner medulla

Question 11

Juxtaglomerular apparatus

Answer 11

With the cortical labrynth. Mesangial cells and Lacis cells which are a type of Mesangial cell which provide support and have a role in the immune system. Juxtaglomerular cells secrete renin which regulates blood pressure in the kidneys.

Question 12

What’s coarse control- renal

Answer 12

Happens in the proximal convoluted tubule, involves large amounts of reabsorption. Reabsorbs all glucose and most water, HCO3, Na and Cl.

Question 13

Lower urinary tract

Answer 13

The pelvis of the kidney, urethra and ureter. Composed of the urothelium, which is surrounded by submucosa, then the loose spiral muscle (longitudinal) and tight spiral muscle (circular)

Question 14

Lining of Glomerulus

Answer 14

The capillaries are surrounded by the fenestrated epithelium meaning it has holes in it, allowing filtration between the capillary walls.

Question 15

Ureter structure

Answer 15

Contains smooth muscle so urine can be passed down by peristalsis, has ‘star-shaped’ lumens

Question 16

Bladder layers

Answer 16

Contains the urothelium, then the submucosal layer (fibrocollagen) and the smooth muscle which has three layers. The smooth muscle and urothelium allow the bladder to extend when full.

Question 17

Urothelium

Answer 17

Structure changes depending on the volume of urine. Its impenetrable to urine. Its in its non-distended state when it is empty, its in its distended state when full of urine and the cells are flattened.

Question 18

Structure of urothelium

Answer 18

Are a type of stratified epithelium. On the top you have the umbrella (dome) cells, they are binucleated and are flattened in distension. They are large and rounded in non-distension. You then have intermediate cells which are polygonal and basal cells which are cuboidal at the bottom.

Question 19

Structure of glomerular filtration barrier

Answer 19

Glycocalyx- luminal surface of endothelial cells in the capillaries of the Glomerular, negatively charged so repels large negatively charged proteins
Fenestrae- openings between the endothelial cells in the Glomerular, water and small molecules pass through. Increases permeability of barrier
Glomerular basement membrane- made of collagen, laminin, fibronectin and proteoglycans. Barrier to filtration. Negatively charged so repels negative particles
Podocytes- foot processes which interlock. Forms filtration slit, negatively charged

Question 20

Peritoneum

Answer 20

A thin serous membrane which lines the abdominal cavity and produces serous fluid

Question 21

Function of peritoneum

Answer 21

Provides serous fluid for lubrication, helps facilitate movement of the organs i.e. in peristalsis

Question 22

Structure of Peritoneum

Answer 22

Has two layers. The visceral peritoneum covers the abdominal organs the parietal peritoneum which lines the abdominal cavity. Both layers are continuous with each other. The viscera peritoneum can be either intraperitoneal or retroperitoneal

Question 23

Peritoneal cavity

Answer 23

The potential space between the two peritoneum layers, contains a small amount of serous fluid but is empty. The peritoneal reflections and the viscera divide the cavity into compartments.

Question 24

Intraperitoneal

Answer 24

When the organs are completely surrounded by the peritoneum. Includes the liver, spleen, gallbladder, stomach, and most of the small and large intestine.

Question 25

Retroperitoneal

Answer 25

When the organs only have peritoneum on their anterior surface. Tend to be organs close to the posterior abdominal wall. Include kidneys, abdominal aorta, suprarenal glands, ureters, oesophagus, rectum, inferior vena cava, and most of the colon, pancreas and duodenum.

Question 26

Subperitoneal viscera

Answer 26

When the viscera is only over the top, includes the pelvic viscera such as the kidney.

Question 27

Two great divisions of the peritoneal cavity

Answer 27

The lesser sac and the greater sac

Question 28

The lesser sac

Answer 28

Posterior to the liver, stomach and lesser omentum.

Question 29

The greater sac

Answer 29

The majority of the peritoneal cavity which is not the lesser sac. Divided into the supracolic and infracolic, they are separated by the mesocolon. If its inferior its infracolic, if its superior it’s the supracolic. The pelvic region is divided by the pelvic viscera and is very inferior.

Question 30

Foramen of Winslow

Answer 30

The communication between the greater and lesser sac, how fluid travels between them

Question 31

Supracolic compartment recesses

Answer 31

Space can form due to the folding of the peritoneum. Important clinically as fluid can accumulate their. The subphrenic recess is below the diaghram. The Hepatorenal recess is between the liver and the kidney. The subhepatic recess is just below the liver

Question 32

Infracolic compartment recesses

Answer 32

The recesses are divided by the root of mesentary into the right and left infracolic recess. You also have the paracolic gutters either side of the ascending and descending colon, clinically any fluid can flow through these gutters to get to any part of the infracolic cavity

Question 33

Pelvic recesses

Answer 33

In the greater sac. Differ between males and females. In females there is space between the bladder and the uterus (vesicouterine pouch). As well as the rectum and the uterus (Rectouterine pouch). In males there is space between the bladder and the rectum (vesicorectal pouch). Abnormal fluid may gather here.

Question 34

Peritoneum and reflections

Answer 34

Because the peritoneum is continuous with itself, it must fold or reflect to cover the abdominal organs. This results in a double layer of peritoneum. The spaces/pouches are described as potential spaces because normally no space would exist and they are empty.

Question 35

Mesentery

Answer 35

Reflection between viscera and abdominal wall. This provides a place for neurovascular (nerves and blood vessels) communication between the organ and abdominal wall.

Question 36

Types of mesentery

Answer 36

One type of mesentery is literally called “The Mesentery”. It’s associated with the small intestine. It will go around all the loops of the small intestine. Another type of mesentry is the mesocolon, which is associated with the colon. You also have the sigmoid mesocolon, which is associated with the sigmoid colon. As well as the mesoappendix which is associated with the appendix.

Question 37

Omentum

Answer 37

Reflection between viscera and other viscera

Question 38

The lesser omentum

Answer 38

The lesser omentum is between the liver and the stomach/duodenum. Double layered. Has some ligaments in it, these are just ways that we decsribe part of the lesser omentum. These are the Hepatogastric ligament (between the liver and stomach) and the Hepatoduodenal ligament (between the liver and duadenum). The Hepatuodenal ligament contains the bile duct, the hepatic artery and the hepatic portal vein.

Question 39

Greater omentum

Answer 39

Runs from the stomach down and then up to the transvers colon. Large fatty sheet that reflects back on itself. It is 4 layered. The layers are fused together. We describe different parts of the greater omentum in ligaments. The Gastrophrenic is between the stomach and the diaghragm. Gastrosplenic is betweeen the stomach and spleen. The Gastrocolic ligament contains the majority of the greater omentum between the stomach and the colons. The phrenicolic ligament is between the colon and the diaghragm

Question 40

Clinical significance of the peritoneal reflections

Answer 40

Excess fluid can build up in the spaces. The spaces are continuous with each other, so provides an avenue for infection to spread throughout the peritoneal cavity. Abnormal excess fluid in the peritoneal cavity is called acitic fluid, when there is ascitic fluid its called ascites

Question 41

Clinical significance of paracolic gutters

Answer 41

Substances can be transported along the gutters to the pelvis or superiorly to the subphrenic recess. The right lateral paracolic gutters provide a continuous route between the supracolic and infracolic compartments.

Question 42

Posterior abdominal wall bones

Answer 42

The L1-L5 vertebral bodies, they curve anteriorly into the abdominal cavity. You have the floating ribs (ribs 11 +12) they are not attached to the sternum. The other major structure is the ilia of the pelvic bone, at the top of the pelvis is the iliac crest. The sacrum is the last part of the vertebral column and the pelvic brim is the edge of the pelvis.

Question 43

Posterior abdominal wall musculatore

Answer 43

The transvers abdominis supports the viscera and rotates and flexes the trunk, its on the side. The Quadratus lumborum is near the lumbar vertebra, it stabilises the 12th rib, quite posterior. There is a group of muscles called iliopsoas, this includes the Poas minor, the Poas major and the Iliacus. They all have the same function and attachment point (femor). The illiacus is also attached to the pelvis and the psoas minor and major attach to the vertebra column.

Question 44

Retroperitoneal viscera

Answer 44

Aorta and IVC close to vertebral columne the aorta is to the right of the IVC, the suprarenal gland is near the top. Parts of the duodenum lie against the aorta and the IVC. Pancreas goes over to the left and is anterior to the kidney, the tail is missing. Ureters are closely related to the psoas major. The ascending and descending colon are quite lateral. Kidneys are at the origin of the psoas major muscle, they are quite superior. The kidney is also anterior to the Quadratus Lumborum. The ureter goes from the kidneys to the bladder, going down the psoas muscle till it has to cross the common iliac artery and vein to get into the pelvis.

Question 45

Posterior abdominal wall vessels

Answer 45

The abdominal aorta descends in the midline. It branches into the coeliac trunk (T12), the superior mesenteric artery (L1), the inferior mesenteric artery (L3). You also have the suprarenal artery which branches near the coeliac trunk (one on either side). The renal and Gonadal arteries (L2), there is one of each at either side. The 4 lumbar arteries are between L1-L4. The inferior vena cave and tributaries. The renal, adrenal and gonadal veins follow their respective arteries.

Question 46

The lumbosacral plexus

Answer 46

Spinal nerves which originate from the spinal cord. The nerves sometimes join together to form new nerves

Question 47

The lumbar plexus

Answer 47

From the anterior rami of spinal nerves (T12-L4). All the nerves emerge within or around the Psoas major. The Genitofemoral nerve emerges anteriorly to psoas major. The obturator nerve is medial to psoas major. The iliohypogastric (anterior) and ilioinguinal nerve (inferior) are lateral to it. They run close to the iliac crest. The lateral cutaneous nerve of the thigh and the femoral nerve are lateral on the surface of the iliacus.

Question 48

The sacral plexus

Answer 48

Goes from L4-S4, L4 therefore supplies both the Lumbar and sacral plexus, this is the Lumbosacral trunk. The sciatic nerve is really big and supplies all of the posterior muscles of the lower limb its what all the nerves of the sacral plexus come together to form

Question 49

The kidneys

Answer 49

Retroperitoneal and is very posterior, they are either side of the vertebral column. Between T12-L3 when we are in the supine position, they move a lot and move with breathing. The right kidney is lower than the left. On the medial surface of each kidney is the renal hilum

Question 50

Structures surrounding the right kidney

Answer 50

Anterior to the right kidney is the liver and part of the small surface. They are intraperitoneal structures, so they are separated from the kidneys by the peritoneum. Retroperoneal structures that are close to the kidneys are the descending part of the duodenum and part of the large intestine. The suprarenal gland is superior to the kidneys.

Question 51

Structure surrounding the left kidney

Answer 51

On the left kidney, you have the stomach to the anterior left which is intraperitoneal. The spleen is more anterior and lateral then the stomach. You also have the small intestine, colon and intestine.

Question 52

Kidney’s fat and fascia

Answer 52

Help protect the kidney. The renal capsule is the first layer of the kidney, it is tough and fibrous. Immediately surrounding this is the perirenal/perinephric fat. Then there is the renal fascia, there are two layers, the anterior and posterior. The last layer of fat is the pararenal/paranephric fat, an anterior and posterior layer of fat.

Question 53

Kidney hilium

Answer 53

Where the vessels enter/leave the kidney. From anterior to posterior there is the renal vein, the renal artery, the ureter, lymphatic and sympathetic vessels. The renal artery is longer on the right kidney and the renal veins is longer on the left kidney. They are direct branches of the abdominal aorta.

Question 54

Where urine drains in the kidneys

Answer 54

The renal column is between the renal pyramids. Urine drains from the renal pyramids to the minor calyx. The minor calyx then combine to form the major calyx. Then the pelvis and the ureter.

Question 55

The ureters

Answer 55

Begin in the hilum of the kidneys at the uretopelvic junction it then drains to the bladder. They are muscular tubes and the urine is drained by peristalsis. They are 25-30cm. There are constrictions in the ureter where it is narrowed slightly, the 3 constrictions are at the renal pelvis, the pelvic brim and the ureteric orifice. The blood supply is from nearby vessels, the veins mirror the arteries.

Question 56

The bladder

Answer 56

Main storage organ of urine, very stretchy to accommodate this. Low in the pelvis but expands into the abdomen. Has strong smooth muscle walls known as Detrusor muscle, these contract when we urinate. Sits anteriorly, shaped like an upside-down pyramid. Ureters enter at the base at an angle. Closes ureters when we urinate so there is no reflux, and it doesn’t go back up. Supplied by internal iliac artery. In females the uterus sits posterior to the bladder. In males the rectum is directly posterior, the prostate gland is inferior to the bladder. In both males and females, the pubic symphysis is anterior. In males you have the internal urethral sphincter which prevents ejaculatory reflux of semen in the bladder.

Question 57

Female urethra

Answer 57

Really short (4cm). Closely related to the anterior wall of the vagina. From internal urethral orifice (bladder) to external urethral orifice (vestibule).

Question 58

Male urethra

Answer 58

A lot longer is about 20cm long but can vary. The male urethra is divided into 4 different parts, the preprostatic, prostatic, membranous, and spongy. In the Preprostatic part is the internal urethral sphincter which is only in males. Both males and females have an external urethral sphincter related to the pelvic floor. The membranous part passes through the pelvic floor and the perineal membrane. The spongy part goes through the erectile tissue. The male urethra curves at the base of the penis.

Question 59

Female catheterisation- clinically relevant anatomy

Answer 59

The labia minora often cover the external urethral meatus meaning it is hard to find in catheterisation. Do not confuse the vaginal orifice or clitoris for the external urethral meatus

Question 60

Male catheterisation- clinically relevant anatomy

Answer 60

Foreskin needs to be retracted during procedure then returned to normal to avoid penile ischaemia. Use a male not female catheter. The two angles of the male urethra are vulnerable to rupture during catheterisation, the initial constriction can be removed by folding the penis perpendicular to the body. To get passes the external urethral sphincter ask the patient to cough

Question 61

Contraindications or catheterisation

Answer 61

1) Urethral injury
2) Postoperative urology patients e.g. following bladder neck or prostate surgery
3) Known urethral obstruction/stricture