Kidney Anatomy PDF

Kidney Dr. Khaled Shoghy Professor of Anatomy & Embryology  The Urogenital System Urinary System Genital System Why the two systems come always together? The common origin of certain elements of both organ in the intermediate mesoderm and adjacent part of the celomic epi...

Kidney Dr. Khaled Shoghy Professor of Anatomy & Embryology  The Urogenital System Urinary System Genital System Why the two systems come always together? The common origin of certain elements of both organ in the intermediate mesoderm and adjacent part of the celomic epithelium The urinary and genital systems of the adult share the final portions of the tracts that deliver their products to outside of body (urethra in the male and the vaginal vestibule in the female). Urogenital system of horse  Urinary system ❑ Two kidneys ❑ The urinary bladder ❑ Two ureters ❑ The urethra  The functions of kidney 1. Filtration of plasma (elimination of waste product). 2. Regulation of fluid and salt balance. 3. Endocrine function: it produce the following hormones: Renin: make arterial constriction to increase blood pressure (convert plasma angiotensinogen to angiotensin I). Bradykinin: make dilatation of blood vessels. Erythropoietin: enhance erythropoiesis.  Position Both kidneys are retroperitoneal, located in sub lumbar region against crura of diaphragm and hypaxial muscles (Psoas Muscles and iliacus muscle). The right kidney lies more cranial than left kidney in all species except pig (both lies at same level).  Anatomy of the kidney (reno, nephro) 1- Colour and consistency: The kidneys are firm and reddish brown 2- Shape: 1) Bean shape in (dog, cat, small ruminants, camel, left kidney of horse) 2) Flattened shape in pig 3) Heart shape in right kidney of horse 4) Oval shape and deeply fissured surface In large ruminants 3- Surfaces: ❑ Dorsal surface: related to last rib, crura of diaphragm and sublumbar Mm. ❑ Ventral surface: related to abdominal viscera. 4- Borders: ❑ Medial: right and left kidneys are related to caudal vena cava and abdominal aorta, respectively. ❑ Lateral: related to abdominal wall  Renal hilus: it is an indentation present in the medial border of each kidney from which arteries, nerves enter to the kidney and veins, ureter and lymphatic vessels leave the kidney. The hilus leads to a dilated part in the center of kidney termed renal sinus. The renal sinus occupied by the renal pelvis. 5- Poles: cranial & caudal Cranial pole: related to adrenal glands (craniomedial). *In all animals except pig, the cranial pole of right kidney is attached to right lobe of liver by hepato-renal ligament 6- Covering: ❑ Fat capsule (capsula adipose): a mass of peri-renal fat which may conceal the kidney. It varies according to species and the condition of animal. ▪ Well developed in ruminants, camel and pig ▪ Moderately developed in carnivores ▪ Less developed in equine. It protects the kidney from the pressure of neighboring organs. ❑ Fibrous capsule: connected to the renal parenchyma. It is blended with tunica adventitia of renal pelvis and renal blood vessels at the renal hilus. It restricts the ability of kidney to expand  Anatomy of the kidney (reno, nephro) Color Shape Surfaces Borders Firm reddish brown 1- Bean shape in (dog, cat, small 1- Dorsal surface: 1- Medial: right and left ruminants, camel, left kidney of horse) related to last rib, kidneys are related to crura of diaphragm caudal vena cava and 2- Flattened shape in pig abdominal aorta, and sublumbar Mm. 3- Heart shape in right kidney of horse respectively. 2- Lateral: related to 4- Oval shape and deeply fissured 2- Ventral surface: abdominal wall surface In large ruminants to abdominal viscera. Poles Covers Cranial & Caudal Fat capsule (capsula adipose): Fibrous capsule: Cranial pole: related to adrenal 1- Well developed (ruminants, restricts the glands camel and pig) ability of kidney Hepato-renal ligament: In all 2- Moderately developed to expand animals except pig (carnivores) 3- Less developed (equine)  General organization of the kidney A- Macroscopic organization Cortex Medulla 1- Renal cortex: The cortex is reddish- brown colour and has granular appearance. In fresh state, it contains very small red dots (renal corpuscles). 2- Renal medulla The medulla is arranged in a form of a several striated conical masses known as medullary pyramids, the base of which directed toward the cortex while the apices directed toward the renal sinus and forming the renal papilla The medulla consists of dark (purplish) outer zone, from which medullary rays extend into the cortex and a paler grayish red inner zone which is radially striated toward the renal sinus. ▪ Renal column: is the part of cortical substance dips between the renal pyramids. ▪ Renal lobe: is the renal pyramid which is surrounded by renal columns and capped with cortical substance. According to the degree of fusion of renal lobes, the kidneys classified as: 1. Smooth kidney (the renal lobes are fused externally) 2. Fissured kidney (the renal lobes are separated externally) in large ruminant. ▪ Renal lobule: is the part of cortex which contains a medullary ray and surrounded by interlobular arteries. ▪ The renal papillae: are either united together or open separately 1- unipapillary kidney: the renal papillae are united together to form a common renal papilla (renal crest) as in dog, small ruminants, camel, horse 2- multipapillary kidney: the renal papillae open separately into a cuplike expansion of renal pelvis called renal calix as in pig and large ruminants.  B- Microscopic organization The parenchyma of kidney is composed of a large number of Uriniferous tubules which connected by intertubular connective tissue. Each tubule consists of: 1. Secretory part (nephron) 2. Conducting part (collecting tubules)  The functional unit 1- Secretory part (Nephron) of the kidney 1- Renal corpuscles: it composed of Bowman's or glomerular capsule which invaginated by a cluster of capillaries form the glomerulus. It can be noticed by eye as red dots scattered throughout the cortex, giving it granular appearance. 2- Tubular part: 1. proximal convoluted tubule 2. loop of nephron (formerly known as loop of Henle) 3. distal convoluted tubule.  2- Collecting part The collecting tubule receives the filtrate from distal convoluted tubules of many nephrons and goes through medulla to form with other tubules a large vessel called papillary duct. The papillary ducts open into the surface of papilla by tiny openings called papillary foramina which convey urine into renal pelvis. The papillary foramina give the surface a sieve appearance so; it is called cribriform area.  Renal pelvis of the kidney The renal pelvis is the dilated proximal part of the ureter in which the papillary ducts open. It occupies the renal sinus and collects the urine to convey it to the ureter. Comparative features of the renal pelvis Large The renal pelvis is absent. Each papillary ruminant duct fits into a short calyx. The short calyces unite to form 2 major calyces which converge from the poles of kidney to form the ureter  Pig The renal pelvis receives several short calyces which is equal to the number of papillary ducts. Dog & small The renal pelvis is central cavity molded by a renal ruminant crest. It receives several recesses on both sides. Equine - The renal pelvis consists of funnel shaped central cavity receives 2 terminal recesses that are directed toward the poles of the kidney. - The mucosa of renal pelvis has tubuloalveolar glands produce mucous secretion which makes physiological albuminuria in the urine of equine with turbid appearance. Camel It is a crescentic in shape with thick renal crest  Large ruminant Camel Pig Equine Small ruminant & Dog  Classification of the kidney Criteria Type of kidney Examples Degree of fusion of 1- Smooth Dog, pig, small ruminants, renal lobes externally camel and equine 2- Fissured Large ruminants Mode of opening of 1- Unipapillary Carnivore, small renal papilla (Form renal crest) ruminants, camel and equine 2-Multipapillary Large ruminants and pig Number of lobes 1- Unilobar Rabbit, rat 2- Multilobar All domestic species  Fixation of the kidney 1- Adjacent structures: 1. Parietal peritoneum 2. Sub-lumber muscles & crura of diaphragm 3. Abdominal viscera 2- Vessels: 1. Renal artery 2. Renal vein 3. Ureter 3- Ligaments: 1. Hepato-renal ligament (in all animals except the pig) 2. Duodeno-renal ligament (in equine only) 3. Reno-splenic ligament (in equine & camel only)  Blood supply of the kidney Abdominal aorta 1. Renal A. 2. Interlobar A. 3. Arcuate A. 4. Interlobular A. gives rami capsularis and 5. Afferent arteriole 6. glomerulus 7. Efferent arteriole 8. straight arteriole (in medulla) 9. Interlobular vein 10.Arcuate vein 11.Interlobar vein 12.Renal vein Caudal vena cava  Criteria Kidney of Dog Kidney of Pig Shape Irregular bean shape Elongated bean shape, flattened dorsoventrally Classification Smooth, multilobar, unipapillary Smooth, multilobar, multipapillary Position ▪ Asymmetric in position ▪ Symmetric in ▪ R. kidney: extend from last position (under intercostal space to 3rd lumbar first 4 lumbar vertebra. vertebrae) ▪ L. kidney: suspended by ▪ R. kidney: don't peritoneum so the position is related to liver affected by degree of filling of stomach  Criteria Kidney of Dog Kidney of Pig Anatomical ▪ Capsula adiposa: ▪ Capsula adiposa: description less developed well developed ▪ Capsular veins are ▪ The size of clear under fibrous Cortex is twice capsule the size of medulla. Weight 57 gm (varies About 235 gm according breed) Others Can be palpated The medullary rays through abdominal and pyramids is wall clear  Criteria Kidney of small ruminants Shape Rounded bean shape Classification Smooth – multilobar- unipapillary Position ▪ Asymmetric in position ▪ R. kidney: under first 3 lumbar transverse process ▪ L. kidney: right to median plane from 3-5th lumbar vertebra Fat capsule The kidney has well developed capsula adiposa Weight 90-150 gm for each kidney Kidney of dog  Criteria Kidney of Large ruminants Shape Right kidney is oval in shape, left kidney is pyramidal in shape Classification fissured – multilobar (12-25 lobe) - multipapillary Position Asymmetric in position as in small ruminants Anatomical ▪ It has well developed capsula adiposa description ▪ Renal pelvis is absent. The papillae (18- 22) open into minor calyx which united to form cranial and caudal major calyces. These calyces unite to form ureter ▪ Renal pyramids and column are clear Criteria Kidney of Large ruminants Right ▪ Oval in shape, has 2 surfaces (dorsal and ventral) Kidney ▪ Lies under last rib to 3rd lumbar vertebra ▪ Cranial pole occupies hepatic renal impression ▪ Weight: 600-700 gm Left ▪ Pyramidal in shape (3 surfaces lateral, medial and Kidney ventral) ▪ The hilus present in medial surface ▪ Cranial pole is pointed, caudal one is rounded ▪ Weight 630-730 gm ▪ Left kidney hangs freely in abdominal cavity by peritoneal fold so, it termed wandering kidney ▪ It presents in median plane caudal to right one. Large ruminant  Criteria Kidney of Equine Shape Right kidney is heart shape, left kidney is bean shape Classification smooth – multilobar - unipapillary Position ▪ Asymmetric in position Anatomical ▪ The has poorly developed capsula adipose description ▪ Weight 700 gm ▪ Hilus on ventral surface, near medial border Right Kidney ▪ Resemble heart on playing cards ▪ Cranial pole occupies the hepatic renal impression, attached to it by hepato-renal ligament Left Kidney ▪ It is bean shape with cranial pointed end ▪ Attached to spleen by reno-splenic ligament  Criteria Kidney of camel Shape Large bean shape classification Smooth – multilobar - unipapillary position ▪ Asymmetric in position Anatomical ▪ it has developed capsula adipose description ▪ Left/right kidneys (413 - 483)/(1075 -1230) g ▪ The renal pelvis is crescentic in shape. Right Kidney ▪ The right kidney lies ventral to the first three lumbar transverse processes ▪ Cranial pole of the right kidney occupies deep hepatic renal impression, attached to it by hepato-renal ligament Left Kidney ▪ Extends from the 5th to 7th lumbar transverse processes ▪ Attached to spleen by reno-splenic ligament  Shape Dog Pig Ox Sheep Horse Camel Flat R. = oval R. = heart Bean compressed Bean Bean L. = pyramidal L. = bean dorsoventrally Capsula adiposa Dog Pig Ox Sheep Camel Horse Less Moderate Well developed developed  Fusion of cortex Dog Pig Ox Sheep Horse Camel Complete Complete Incomplete Complete Complete Complete smooth smooth fissured smooth smooth smooth Fusion of renal papillae Dog Pig Ox Sheep Horse Camel Renal crest Separated Renal crest Renal crest Renal crest Unipapillary Multipapillary Unipapillary Unipapillary Unipapillary  Position Dog Pig Ox Sheep Horse Camel R: 12R-2L R: 1L-4L R: 13R-3L R: 13R-2L R: 16R-1L R: 1L-3L L: 13R-3L L: 1L-4L L: 3L-5L L: 4L-5L L: 17R-2L L: 5L-7L  Renal pelvis Dog Pig Ox Sheep Horse Camel - Central - Central - No renal - Central - Funnel shaped - Crescentic cavity cavity pelvis cavity central cavity shape Receives - 2 major - 2 major Receives With 2 terminal central renal crest calyces calyces renal crest recesses cavity - Recesses - 8-12 minor -18-22 minor - Recesses - Mucous mem.: receives on both calyces calyces on both tubuloalveolar thick renal sides sides gland give the crest turbid appearance Arrangement of renal vessels & ureter in renal hilus Dog Pig Ox Sheep Horse Camel A U A V A A U A V U V V V V U A U U A = Renal artery V = Renal vein U = Ureter  Hepato-renal ligament & impression Dog Pig Ox Sheep Horse Camel Present Absent Present Present Present Present Duodeno-renal ligament Dog Pig Ox Sheep Horse Camel Absent Absent Absent Absent Present Absent Reno-splenic ligament Dog Pig Ox Sheep Horse Camel Absent Absent Absent Absent Present Present Comparative features of the kidney