Urinary S1 (Needs Imaging) Flashcards
How many Kidneys are found in the human body?
Where are they located?
How much does each kidney weigh?
2 kidneys
Retroperitoneal organs
Lateral to vertebrae (T11 to L3)
Left higher than right
150g each
What structures immediately surround each kidney?
Enclosed by a capsule (which also encloses the suprarenal glands)
Suprarenal glands separated from kidneys by a septum
All enclosed in perirenal fat and pararenal fascia
Label the lines according to the structures that overly the kidneys at each point
From top left anticlockwise:
Right suprarenal gland
Liver
Desc. Duodenum
R. Colic flexure
Small intestine
Jejunum
Desc. Colon
Left colic flexure
Pancreas
Spleen
Stomach
Left suprarenal gland
What are the posterior relations of the kidneys?
Left kidney
Top 1/3:
- Rib XI and XII
- Diaphragm
Lower 2/3 (From medial to laterally)
- Psoas major
- Quadratus lumborum
- Transversus abdominis
Right Kidney:
- As above but excluding Rib XI (R. Kidney lower)
Describe the Hilum of the Kidneys
Vertical clefts in the medial margins
Renal arteries, Veins and the ureters enter/leave here
VAU (vein, artery, ureter) Anterior to posterior
Describe the Venous drainage of the kidneys
What is the clinical relevance?
Renal veins drain both kidneys into the IVC
Left renal vein must cross the midline, lies between Superior mesenteric artery and the aorta
Clinical:
Aneurysm in the abdominal aorta could compress left renal vein
Describe the Renal arteries
What is the most common anomaly and the clinical significance of this anomaly?
Normally one renal artery to each kidney supplied by the Abdominal aorta
Right renal artery passes inferior to IVC
Multiple renal arteries to one kidney is a common anomaly
These multiple arteries are end arteries that do not anastomose and so occlusion of one will lead to kidney tissue ischaemia/necrosis
Label the black boxes
From top left anticlockwise:
Pyramid in renal medulla
Renal cortex
Renal papilla
Renal sinus
Minor calyx
Ureter
Renal Pelvis
Renal vein
Renal artery
Major Calyx
Renal Column
Through which structures does filtrate/urine pass in kidneys before reaching the bladder?
Filtrate in the cortex is filtered throught the nephrons to the collecting ducts in the medulla
Urine passes throught collecting ducts in the renal pyramids to the papillae at the apex of each pyramid
Papillae drain into minor calyx, which in turn drains into the major calyx
Major calices drain to the renal pelvis, then through the ureters to the bladder
Follow the course of a red blood cell from the left renal artery to the left renal vein
Hint: Make sure to go into detail of vasculature surrounding each nephron
Arterial:
Renal Vein
Segmental artery
Interlobar artery
Arcuate artery
Interlobular artery
Afferent arterioles
Glomerulur tuft
Efferent arteriole
THEN EITHER
Peritubular capillaries which drain into cortical venules
OR
Vasa recta, which drain into the venae recta
Venous:
Cortical venules or venae recta
Interlobular vein
Arcuate vein
Interlobar vein
Segmental vein
Renal vein
Where can the kidney recieve abberant blood supply from?
Extra renal arteries
Superior mesenteric artery
Suprarenal artery
Testicular or ovarian arteries
What 3 constrictions are present in the ureters as they travel from kidney to bladder?
- The Junction of the renal pelvis
- At pelvic brim
- Where it pierces the bladder wall
At what level do the ureters cross the pelvic brim?
What is the closest major vasculare structure at this level?
At the level of the sacro-iliac joint
The ureter pasess anterior to the bifurcation of the common iliac artery at this level
Describe the course of the ureters from Hilum to Bladder
Descends anterior to psoas major
crosses pelvic brim at level of sacro-iliac joint
**In Women: **
Uterine artery passes over the ureter (water under the bridge)
In Men:
Ureter passes under the vas deferens
Then:
- Ureters enter the posterolateral aspect of the bladder and run obliquely throught the bladder wall
Given the most likely cause of trauma to the ureters
During hysterectomy or oophorectomy in women damage to the ureters can occur
Apart from trauma, what is the other major clinical aspect of ureters? Explain in detail
Uretic stones can be passed from kidney
Can get caught at uretic constrictions causing renal colic
Smooth muscle spasms that are normally a function of peristalsis try to clear the stone
This can cause pain from visceral sensory nerves T11 to L2
This presents as groin, loin and flank pain
Givea a very brief description of bladder structure (3 points)
Hollow
Distensible (transitional epithelium)
Muscular walls
Where is the bladder found and how is it shaped?
Hint: Different states
Empty:
Lies in the lesser pelvis inferior to the peritoneum
It is a tetrahedron
Posterior base, superior side and two inferolateral sides
Full:
Rises into the greater pelvis and above the pubic bone, may reach as high as the umbilicus. Still lies inferior to peritoneum
Spherical in shape
Give short descriptions of the specific regions/structures of interest within the bladder (5 points)
Apex (anterior angle):
Connection here to urachus, seen as the median umbilical ligament
Trigone:
Defines posterior wall, oblique openings to the ureters and internal urethral opening in a triangle shape, smooth walled
Interureteric fold:
Ridge between two ureter openings
Neck:
Where base and inferolateral sides meet
Involuntary internal sphincter:
Circular region of detrusor muscle at neck acting as sphincter
Describe the bladder walls (3 points)
Rugae in mucosa except within trigone
Transitional epithelium
Detrusor muscle is the muscularis propria, formed of longitudinal, circular and oblique fibres
How is the prostate involved in urination?
Can occlude urethra preventing urination
Enlargement normal with age in response to male hormones
How long is the urethra?
Females:
4-5cm
Males:
~20cm
Describe the course of the male urethra
Include notes on structure in each section
Preprostatic:
Small section of urethral between bladder and prostate
Transitional epithelium
Prostatic:
Section of the urethra that passes through the prostate, ejaculatory duct and prostatic ducts drain into urethra here
Transitional epithelium
Membranous:
Small section of urethra passing through the external urethral sphincter and the deep peritoneal pouch
Stratified columnar epithelium
Spongy (Penile):
Longest section passes through the penis (corpus spongosium)
Stratified columnar proximally
Stratified squamous distally
What is the clinical significance of the Membranous section of the male urethra
Can be damaged during catheterisation
Describe the course of the female urethra
Passes between the glans clitoris and the vaginal opening
Passes through the deep perenial pouch first, this is where the external urethral sphincter resides
Then passes straight to the external urethral orifice
What is the clincial relevance of the female urethra?
Greater chance of UTIs than men due to closeness to the anal orifice and short length
What are the general functions of the kidneys? (4 points)
Regulation:
Controls concentrations og key substances (ions and small organic molecules) in ECF
Excretion:
Filters waste products from blood
Endocrine:
Synthesis of renin, erythropoietin, prostaglandins
Metabolism:
Produce active Vit. D
Catabolism of Insulin, PTH, calcitonin
Describe the water content of a 70Kg Medical student
40L total
ICF:
25L
ECF:
Interstitial fluid - 12L
Intravascular - 3L
Lymph
Synovial, intestinal, CSF, Sweat, Urine, Pleural, Peritoneal, Pericardial, Intraocular
Describe what is meant by the terms:
Osmolality
Osmolarity
Oncotic
Osmolality:
Solute per Kg of solvent
Osmolarity:
Number of osmoles (ions and organic molecules) of solute per litre
measured in milli-osmoles
Oncotic:
Osmotic force due to proteins
How do you make water cross a cell membrane?
Have differnt osmolarities across the membrane
Water moves from areas of low to high osmolarity
Compare the ICF and ECF in terms of relative amounts of electrolytes
Why are they different?
What can happen in the case of disturbance to this balance?
ECF:
High Na+ and low K+
Many large organic anions
ICF:
High K+ and low Na+
Main anions Cl- and HCO3-
Difference:
Maintained by active transport mechanisms
(E.g. Na+/K+ATPase)
Disturbance:
Failure to control electrolyte balance will affect transport and electrical functions
How do the Kidney interact with bodily fluid?
Affects ECF directly by changing volume and compostion
This has indirect effect on the ICF
How does failure of the kidney to regulate ECF volume and composition affect the body?
Hint: Keep it general
Volume:
Changes in BP, Tissue fluid and cell function
Composition:
Changes in osmolarity cause cells to shrink or swell
What 2 major factors affect homeostatic regulation of ECF/ICF in a normal physiological state?
Variable ingestion of water and salts
Loss of water and salts
How do the kidneys affect the acid/base balance of the body?
Control concentration of Bicarbonate in plasma
How much does the kidney filter every minute/day and what is this called?
What is the general composition of this filtrate?
How much ends up being excreted?
125ml/min or 180L/day - Glomerular filtration rate
Produces an ultrafiltrate of water, ions and small molecules
Leaves on average 1.5L or urine a day
What is the functional unit of the kidney?
How many are found in each kidney?
Nephron
1.5 million
Give the basic areas of the nephron and where they are found
Cortex:
Glomerulus, PCT, DCT
Medulla:
Loop of Henle
Collecting duct (passes into pelvis)
What is the function of epithelium in the nephron?
Filtration of plasma
Excrete waste produces
Reabsorb needed materials from ultrafiltrate
**1. **Give a list of normal substances the kidney will reabsorb and proportions of that material that are reabsorbed from ultrafiltrate
**2. **Give an example of a substance that is actively excreted
1.
Water - 99% reabsorbed
Na+ and Cl- 99%
Bicarbonate - 100%
Gucose and amino acids -100%
2.
H+ actively excreted by epithelium (lose more than is filtered)
What is the blood flow required by the kidney?
What proprtion of cardiac output does this represent?
4ml/g/min
25%
Decribe in general terms how the kidney produces ultrafiltrate
Glomerulus filters water, ions and small molecules by constant filtration pressure in capillaries
Specialised circulation (affernet and efferent arterioles) maintains filtration pressure
Describe the functions of the PCT
Major site of reabsorbtion:
60-70% water
80-90% Na+ and K+
90% Bicarbonate
100% glucose and AAs
Reabsorbed materials then leave via peritubular capillaries
Is the fluid in the PCT hypotonic, isotonic or hypertonic?
Explain
Isotonic
Water follows osmotic gradient produces by reabsorbtion
What is meant by ‘Kidney epithelia are polarised’
Why is this important
Polarisation:
Differnt membrane transporters on luminal and basolateral membranes
This allows transport across the epithelium
Explain how Na+/K+ATPase transporters are involved in reabsorbtion at the PCT
Na+/K+ATPase extrudes Na+ across basolateral membrane
Na+ enters cells from lumen down conc gradient
Energy from soudium movement used to drive reabsorbtion of other sultutes such as glucose
Water follows osmotically
What are the functions of the Loop of Henle?
Reabsorbtion:
Further reabsorption occurs
Counter current multiplication:
Creates a gradient of increasing osmolarity in the medulla
Allows formation of concentrated urine to conserve water
Describe the modification of urine in the DCT
Site of variable reabsorbtion of electrolytes and water
Takes hypotonic fluid leaving LoH and removes yet more Na+ and Cl-
Actively secretes H+
Water can move into or out of lumen
If net movement is into the lumen then large volumes of dilute urine formed (Diuresis)
Describe how the collecting duct affects urine production
Collecting duct passes through high osmolarity medulla
If CD is water permeable, water moves out and concentrated urine is produced
If CD not permeable to water, urine remains dilute
Describe the hormonal basis of variable reabsorption in the distal nephron
Renin angiotensin system:
Controls sodium recovery and hence controls ECF volume/amount of water reabsorbed
Anti-Diuretic hormone:
Controls permeability of the DCT and collecting ducts
This controls ECF osmolarity
