Renal anatomy Flashcards by Hettie Stevens

Inner blood supply to kidney

Renal artery -> Interlobar arteries (between medullary pyramids)

> Arcuate arteries (along cortico-medullary junction)
> Interlobular arteries (into cortex)
> Afferent arterioles, glomerular capillaries

Venous drainage the same
- veins thinner walls, larger lumen

How well did you know this?

Not at all

Perfectly

Renal cortex

Darker, granular
Dense peritubular capillary network surrounding tubules in any spare space
Renal corpuscle includes glomeruli + Bowman’s capsule

How well did you know this?

Not at all

Perfectly

Proximal vs distal convoluted tubules in renal cortex

Proximal tubules - no clear lumen, brush border, dark pink
Distal tubules - wider limen, pale purple (as less mitochondria)

More proximal than distal visible, as more convoluted and longer

How well did you know this?

Not at all

Perfectly

Renal medulla

Paler, parallel striations
Collecting ducts lined by columnar epithelium
Descending think limb lined by squamous epithelium
Ascending thick limb of loop of Henle lined by cuboidal epithelium
Vasa recta capillaries contain RBCs

How well did you know this?

Not at all

Perfectly

Medullary rays

Medullary tissue that perforates renal cortex
Between interlobular arteries and veins
Contains collecting tubules and loops of Henle
To drain fluid from the most superficial, subcapsular nephrons
(rays reaching into granular tissue)

How well did you know this?

Not at all

Perfectly

Renal pelvis

Simple columnar epithelium at papilla

Transitional epithelium at pelvis -> ureter

How well did you know this?

Not at all

Perfectly

Ureter histology

Ragged outer connective tissue (torn, as retroperitoneal in extraction)
Longitudinal inner and circular outer smooth muscle
Muscular tube that moves urine by peristalsis
Accomodates lumen size to volume of urine conveyed - transitional epithelium can be relaxed or stretched
Urothelium create watertight boundary, impermeable to water and urine

How well did you know this?

Not at all

Perfectly

Transtitional epithelium

Lines renal pelvis, ureter and bladder
3-6 cell layers, stratified

Basal - cuboidal, dividing cells
Intermediate - columnar cells
Surface - umbrella cells, large ovoid cells

How well did you know this?

Not at all

Perfectly

Umbrella cells

Large ovoid cells projecting into lumen

Form watertight barrier - luminal membranes are thick, with high lipid content, and desmosomes (fibrils to hold cells together for unified contraction) and tight junctions

Adapted to enable stretch of urothelium - luminal membranes have accordion-like, pleated capability so that cells can lengthen quickly when flow of urine increases and lumen is distended - also allows small calculi (stones) to pass without damaging lining

How well did you know this?

Not at all

Perfectly

Bladder histology

Sac-like, expandable store
Propels urine out - no peristalsis but single unified contraction

Outer connective tissue
Smooth muscle, elastic fibres
Delicate muscularis mucosa
Lamina propria
Transitional epithelia

How well did you know this?

Not at all

Perfectly

Structure of kidney

Superior and inferior poles
Renal hilum has renal vein, renal artery and pelvis (AP)
Lymph drains to para-aortic nodes, lumbar

Function of excretion and electrolyte balance

How well did you know this?

Not at all

Perfectly

Capsules of kidney

Fibrous capsule - adherent to kidney surface
Perinephric fat - solid, protective adipose tissue
Renal fascia - extraperitoneal fascia
Pararenal fat

How well did you know this?

Not at all

Perfectly

Posterior relations of kidney

Psoas major, transversus abdominus, quadratus lumborum, diaphragm
12th rib (and 11th on left)
Subcostal, iliohypogastric, ilioinguinal nerves

How well did you know this?

Not at all

Perfectly

Anterior relations of kidney

RIGHT
Adrenal gland, liver, duodenum, right colic flexure
LEFT
Spleen, stomach, jejunum, pancreas, left colic flexure

How well did you know this?

Not at all

Perfectly

Adrenal glands relations

Right - posterior to liver
Left - posterior to stomach and pancreas
Lie within coverings of perinephric fat and renal fascia

How well did you know this?

Not at all

Perfectly

Adrenal gland structure

Outer cortex and inner medulla
Right is pyramidial, left is semilunar shaped
Supplied by branches from inferior phrenic arteries, aorta and renal arteries
Sympathetic nerves from sympathetic chain to renal plexus, along renal vessels
Afferent sympathetic fibres enter spinal cord at T11-12

Adrenal gland function

Medulla - produce hormones, tyrosine -> adrenaline, noradrenaline, dopamine
Cortex - produce cortisol and aldosterone

Developmental abnormalities in kidney

Polycystic kidneys
Horseshoe kidney - caught on IM vessels
Duplication of ureter - may fuse before bladder or enter bladder separately
Ectopic ureter - opens into urethra or vagina
Pelvic or thoracic kidney

Ureter structure

25cm long muscular tube
Lined with urothelium, transitional epithelium
Retroperitoneal

ABDOMINAL URETER - lies on psoas major
PELVIC URETER - from L4, bifurcation of common iliac artery. Turns anteriorly and medially at ischial spine level. Lies close to seminal vesicle and runs under vas deferens in male, lateral to cervix and under uterine vessles in female
INTRAVESICAL URETER - pierces bladder at angle to prevent backflow of urine, high pressure in bladder collapses ureter

Blood supply and lymph drainage of ureter

Blood supply is from local arteries along its course, venous drainage from corresponding veins - aorta, renal artery, gonadal artery, internal iliac artery, inferior vesical artery
Lymph drains to lumbar nodes
Nerve supply via autonomic plexuses

Surface anatomy of kidneys

T12 to L3

Hilum - left kidney at L1, right kidney at L2 (liver in way, so more likely to feel right), 5cm from midline

Pain

Urinary tract - loin to groin (T12 dermatome)
Kidneys - loin/flank level back pain

Renal colic (calculi) - waves of spasmodic pain as muscle walls try to squeeze down
Renal cancer - unremittent, non-radiating

Lumbosacral plexus

Iliohypogastric - L1, together
Ilioinguinal - L1, together
Genitofemoral - L1/2, emerges from psoas
Lateral cutaneous - L2/3, under inguinal ligament to supply lateral thigh
Obturator - L2/3/4, big, deep, to medial thigh
Femoral - to femoral triangle

Bladder

Trigone smooth area
Detrusor smooth muscle wall, rugae when empty
Maximum capacity 500ml
Urachus (obliterated allantois) is attached to apex of bladder, in fold of peritoneum - median umbilical fold, umbilical artery in here

Relations of bladder

Empty - in true pelvis, posterior to pubic symphysis Male - rectum, vas deferens, seminal vesicle posterior Female - rectum, uterus posterior Lateral - ischioanal fossa, obturator internus, levator ani Superior - sigmoid colon, ileum Inferior - prostate (male), vagina (female)

Blood and lymph supply to bladder

Superior and inferior vesical arteries from internal iliac artery Vesical venous plexus drains to internal iliac veins Lymph drains to internal and external iliac nodes

Innervation to bladder

Sympathetic - from sympathetic trunk Parasympathetic - pelvic splanchnic nerves, S2-4 Fibres join pelvic (inferior hypogastric) plexus on each side of bladder, then to bladder itself

Female urethra

4cm long Supported by/embedded in anterior wall of vagina External urethral meatus opening in folds of labia

Male urethra

15-25cm long PREPROSTATIC - embedded in bladder neck PROSTATIC - within prostate, 15-20 prostatic ducts empty into prostatic sinus on each side of urethral crest, openings of ejaculatory ducts on each side MEMBRANOUS - through external urethral sphincter and perineal membrane PENILE (SPONGY) - within bulb and corpus spongiosum of penis Opens at tip of glans of penis

Benign prostatic hyperplasia

BPH Commonest urinary tract pathology in men Enlarged prostate obstructs urine outflow, residual urine predisposes to infection, back pressure can lead to hydronephrosis and post renal failure May be palpable as smooth mass felt on rectal examination Treat with intermediate catheterisation, alpha blockers, surgery (TURP or radical prostatectomy)

Autonomic fibres controlling continence and micturition

- parasympathetic efferents, motor to detrusor and inhibitory to internal sphincter -> micturition - parasympathetic afferents convey information about distension, involved in parasympathetic reflex where distension-> emptying - cortical inhibition learned in potty training, micturition becomes voluntary action - sympathetic efferents are antagonistic and vasomotor, enable continence by inhibiting detrusor contraction and strengthening internal urethral sphincter

External urethral sphincter

Striated muscle controlled by pudendal nerve Mid-flow stop achieved by contraction of external urethral sphincter and delayed reflex relaxation of detrusor muscle -> active continence, assisted by pelvic floor (levator ani) contraction

Incontinence

Stress incontinence - weakness of external urinary sphincter and pelvic floor, urination when raised intra-abdominal pressure, common after childbirth Urge incontinence - overactive detrusor muscle leads to frequent urination, but passing little urine Overflow incontinence - bladder overexpanded, due to prostatic hypertrophy or loss of communication, when bladder is distended

Urethral catheterisation

To facilitate flow of urine through urethra Catheter inserted into external urethral meatus and gently advanced Will angle superiorly in bulb of penis as it pierces perineal membrane above, prostatic urethra curves forward Balloon inflated once in place

Supra-pubic catheterisation

To drain urinary bladder in patients who cannot be catheterised via urethra, or who need long-term catheterisation As bladder fills, enters abdomen, and peels peritoneum form lower abdominal wall Suprapubic catheter therefore does not pierce peritoneum and enter peritoneal cavity