macroscopic anatomy of the urinary tract Flashcards
where are the kidneys located
- paired organs
- lie retro-peritoneally
- positioned in the dorsal abdomen
- positioned in the ventral lumbar region with limited mobility (except cat)
- right is most cranial (except in pig) lies in small fossa of the caudate liver lobe
- left kidney is most mobile
outline the anatomical landmarks of the left kidney
- cranial pole contacts the greater curvature of the stomach
- dorsomedial aspect of the cranial pole contacts the spleen laterally
- often the spleen is located ventral to the kidney making a useful acoustic window
- cranially the left kidney may contact the left limb of the pancreas
- medially the cranial pole contacts the left adrenal gland
- caudally there is small intestine and descending colon
- the ovary if present is located caudally and ventrally
outline the anatomical landmarks of the right kidney
- cranial pole is located within the renal fossa of the caudate lobe of the liver
- medially is the caudal vena cava
- dorsolateral to the caudal vena cava close to the medial aspect of the right kidney is the right adrenal gland
- ventrally is the descending duodenum
- ventrally and medially is the right pancreatic limb
- the ovary if present is caudoventral to the right kidney
how do you visualise the kidneys surgically
- retract mesocolon on left hand side to see left kidney
- retract mesoduodenum on right hands side to see right kidney
what are the basic components of the kidney
- outer fibrous capsule
- renal cortex
- renal medulla
the kidney is described as bean shaped in which species
- dog
- cat
- sheep
- goat
describe the appearance of equine kidneys
- more triangular
- right described as heart shaped
- left described as pyramidal
how are porcine kidneys described
long and flat
describe the appearance of bovine kidneys
- oval and irregular in shape
- obvious lobules = reniculate
what is a unilobular kidney
kidney with only one renal lobe (functional unit = lobe = cortex and medulla that work together)
which species have unilobar kidneys
rodents and lagomorphs
describe the kidney of the cow
- seperate cortices
- seperate medullae
- multiple lobes/pyramids
- multiple renal papillae
- multiple calices
- no pelvis
- lobulated surface
describe the kidney of a pig
- fused cortex
- seperate medullae
- obvious pyramids
- multiple renal papillae
- multiple calices
- branched pelvis
- smooth surface
describe the internal appearance of the kidney in the dog, cat, sheep, and horse
- fused cortex
- fused medullae
- lobes still seen internally
- pyramids partially merged
- papillae merged to form renal crest
- no calices
- single pelvis
- smooth surface
compare the kidneys across species
what is the difference between a calice and a pelvis
- the urine drains from the tip of the pyramids
- cattle pigs and primates have seperate pyramids, then each has a funnel attached to collect the urine (mino calyx)
- 2-3 minor calices drain into a major calyx
- major calices drain directly into the ureter in cattle
- in pigs and primates the major calices drain into a space called the renal pelvis which then drains into the ureter
- in dogs, cats, sheep and horses the medullary cones are fused (renal crest) and they have n calices. renal crest then draines into the renal pelvis
where is the renal pelvis located in the dog
renal sinus
discuss how the renal pelvis differs between species
- large irregular structure with broad finger like processes called recesses in single lobe species
- in the horse there are only 2 recesses
- smaller irregular structure with short stems ending in a dilated regione called calyces in pigs and primates
- divided proximal ureter leading to multiple calyces in cattle (no pelvis)
discuss internal renal vasculature
- basic flow is from hilus to cortex then cortex to medulla
- drainage is from medulla back to cortex to join cortical venous drainage
- arterial and venous patterns the same for large intra-renal vessels
- intra renal portal system
- outflow via hilus
outline the renal blood flow circuit
- aorta
- renal artery
- interlobar artery
- arcuate artery
- inter-lobular artery
- afferent glomerular artery
- glomerulus
- efferent glomerular artery
- renal tubule plexus
- inter-lobular vein
- arcuate vein
- inter- lobar vein
- renal vein
- caudal vena cava
describe the microvascular anatomy from the glomeruli
cortical glomeruli: peritubular capillaries in the cortex
juxtamedullary glomeruli: peritubular capillaries in cortex (90%) OR vasa recta in the medulla (10%)
explain how blood flows in the juxtamedullary nephrons
- afferent arteriole firstly enters bowmans capsule the the efferent arteriole exits
- the efferent vessel splits and supplies the peritubular capillaries around the PCT and DCT the drains to veins in the cortex
- the vasa recta around the LoH then drains to the arcuate veins
discuss the walls of the ureter and bladder
made up of
- mucous membrane
- urothelium (transitional epithelium)
- apical cellular protection against urine due to tight junctions
- urothelial cells tolerate stretching as bladder
- lamina propria
- muscular layer
- adventitia
what are the ureters
- bilateral muscualr tubes which pass within the retroperitoneal space
- abdominal portion
- pelvic portion (directed medially through either the broad ligament or mesoducts
- ureter ends on the dorso-lateral bladder surface (within the lateral ligament of the bladder)
how do the ureters enter the bladder
the ureter enters the bladder obliquely and runs intramurally between the muscular layer and mucosa before opening through two slits often on a slightly raised hillock
discuss the bladder
- a hollow muscular-membranous organ
- varies in size and position depending on degree of filling
- divided into cranial pole, intermediate body and caudal neck
- lining cells are endoderm-derived
- urothelium
- designed to be stretchy and tolerant of distortion (other cells die when distrorted)
- special anti-urine junctions between cells
what are the ureteric folds
two folds extend from the ureteral openings to the neck of the bladder where they fuse to become the urethral crest
how is the bladder attached to the abdominal wall
- two lateral ligaments of the bladder insert in the dorsal abdominal wall (within them are residual umbilical vessels)
- the median ligament connects the bladder to the pelvic floor and linea alba
discuss the female urethra
- empties at the external urethral orifice onto the ventral wall of the vagina at the vestibulo-vaginal junction
- conveys urine only
- length and diameter vary considerably between species (short and wide in mare, bordered by two fossae in bitch, sow and cow have significant sub-urethral diverticulum)
discuss the male urethra
- empties at the tip of the penis
- divided into pre-prostatic from bladder neck to seminal hillock
- prostatic portion (includes openings of derent, vesicular and prostatic ducts)
- penile portion (from ischial arch to penile tip)
discuss the external renal vasculature
- renal arteries originate from the lateral aspect of the aorta
- arteries often divide into a dorsal and ventral branch before entering the kidney
- left renal artery originates 2 cm caudal to the right renal artery
- left renal vein is immediately ventral to the artery
- right renal artery arises 4 cm caudal to cranial mesenteric artery then transverses dorsal to the caudal vena cava
- right renal vein is immediately ventral to the renal artery
what is the blood supply to the bladder
caudal vesicular artery
what is the blood supply to the urethra
urethral artery
what is the lymphatic drainage to the kidney
renal lymph nodes
what is the lymphatic drainage of the ureter
lumbar lymph nodes
what is the lymphatic drainage from the bladder
iliosacral lymph nodes
what is the innervation of the kidney
- sympathetic and parasympathetic fibres from solar plexus via renal arteries
- sympathetic fibres from synapses in coeliac ganglion and cranial mesenteric ganglion
what is the innervation of the bladder
- sympathetic via the hypogastric nerve from the caudal mesenteric ganglion
- parasympathetic from the pudendal nerve
