C21 - Kidney and its blood supply

Question 1

Structures to mention on the kidney

Answer 1

• Margo lateralis
• Margo medialis
  
  • Hilus renalis (Medial border where vesses and ureter are attahed)
  • Sinus renalis (A cavity at the hilus renalis. Contains fat and connective tissue surrounding the renal pelvis and vessels)
• Facies ventralis
• Facies dorsalis
• Extremitas cranialis
• Extremitas caudalis
• Capsula adiposa (Surrounds the kidney outside the capsula fibrosa)
• Capsula fibrosa (On the surface of the kidney)
• Lobi renales (Each consists of a renal pyramid and its cortical cap. Bo: persist on the surface. It is indicated in other mammals by the pyramides renalis and interlobar vessels seen in section)
• Cortex renis (Outer layer. Covers the basis pyramidis and extends between them as columnae renales)
  
  • Lobuli corticales (Each lobule consists of a medullary ray and the surrounding pars convoluta)
    
    • Pars convoluta (Consists of convoluted tubules and renal corpuscles)
    • Corpuscula renis (Consists of a glomerulus invaginated into a capsule)
    • Glomeruli (A knot of capillaries in a corpusculum renis)
    • Pars radiata (Bundles of straight tubules extending from medulla → cortex)
• Medulla renis (Consists of the pyramids)
  
  • Pyramides renales (The base of each is at the cortex and the apex is a renal papilla in the pelvis of calyx)
    
    • Basis pyramidis (Covered by cortex)
    • Papilla renalis (bo, su) (Apices of the pyramids. Su, ru: separate, each with its own calyx. Car, eq: fused to form crista renalis)
    • Crista renalis (eq, ca) (Papillae renalis are fused to form the crista renalis)
    • Ductus papillares (Large terminal duct)
    • Area cribrosa (Cribiform area of the papilla or crest perforated by the openings of the papillary ducts)
• Columnae renales (Sections of crests of cortical tissue extending into the medulla around and between the pyramids)
• Tubuli renales
• Pelvis renalis (The dilatation at the beginning of ureter in the renal sinus)
  
  • Recessus pelvis (ca) (Each recess embraces a ridge formed by a pyramid leading to crista renalis)
  • Calices renales (bo, su) (Papillae are separated)
  • Recessus terminales (eq) (Tubular diverticula of pelvis renalis which extend into the cranial and caudal ends of the kidney)
• Arteriae renis
  
  • Arteriae interlobares (From sinus toward cortex between the pyramids)
    
    • Arteriae arcuatae
  • Arteriae interlobulares (Penetrate pars convoluta of the cortex
  • Arteriola glomerularis afferens
  • Arteriola glomerularis efferens (From the glomerolus to capillaries between tubules)
  • Rami capsulares
  • Arteriolae rectae
• Venae renis
  
  • Venae interlobares (Betwen pyramides renalis)
  • Venae arcuatae
  • Venae interlobulares (In pars convoluta of cortex)
  • Venulae stellatae (eq, ca) (Capsular branches of vv. ilerlobulares)
  • Venulae rectae (Drain medulla to vv. arcuratae)
  • Venae capsulares (fe) (Capuslar veins. Branch off the v. renalis at the hilus. Form a characteristic network)

Question 2

List the interspecies differences

Answer 2

• Medulla renalis
  
  • Pyramides renalis
    
    • Papilla renalis (bo, su)
    • Crista renalis (eq, ca)
• Pelvis renalis
  
  • Recessus pelvis (ca)
  • Calices renalis (bo, su)
  • Recessus terminalis (eq)
• Venae renis
  
  • Venulae stellatae (eq, ca)
  • Venulae capuslaris (fe)

Location:

• Right kidney is located further cranial than left kidney (ø su)
• Ru: rumen pushes the left kidney towards the right half of the abdomen

Shape:

• Unilobular with smooth surface and single renal papillae (Car, eq, small ru)
• Multilobular with smooth surface and multiple papillae (su)
• Multilobular with lobulated surface and multiple papillae (ox)
• Eq: right kidney is heart shaped

Surface:

• Lobulated (ru)
• Smooth (others)

Tips of pyramids renalis:

• Separated (ru)
• Fused (others) (partly/completely)

Question 3

Give the function of the kidney

Answer 3

• Eliminate waste products from the blood
• Regulate the fluid and salt balance of the body
• Removing foreign substances from the blood (detoxifying)

Question 4

Give the location of the kidneys

Answer 4

• Lying retroperitoneal pressed against the dorsal abdominal wall on either side of the vertebral column
• Within the lumbar region
  
  • ​But they extend cranially under the last ribs into the intrathoracic part of the abdomen.
• Each kidney is embedded in capsula adiposa (++ ru, su)
  
  • ​Protects against pressure from adjacent organs
• Right kidney:
  
  • ​Located further cranial than left kidney (ø su)
  • In contact with processus caudatus of the liver and lobus hepatis dexter
    
    • ​Lies in impressio renalis of the liver (limits movement)
• Left kidney:
  
  • ​More mobile than the right
  • Ru: rumen pushes the left kidney towards the right half of the abdomen

Question 5

Shape of the kidneys

Answer 5

• Bean-shaped (car, sheep, goat, left kidney of eq)
• Flattened (su)
• Heart shaped (right kidney eq)
• Irregular oval shape (ru)

Question 6

Structure of the kidney

Answer 6

• Unilobular with smooth surface and single renal papillae (Car, eq, small ru)
• Multilobular with smooth surface and multiple papillae (su)
• Multilobular with lobulated surface and multiple papillae (ox)

Question 7

Cortex renalis

Answer 7

• Outer layer of the kidney
• Reddish-brown color
• Covers the base of the pyramids and extends between them as columnae renales
• Ultrafiltation occurs in the renal cortex
• Divided into:
  
  • Zona peripherica
  • Zona juxtamedullaris
• Lobuli corticales
  
  • ​Pars convoluta
  • Corpuscular renis
  • Glomeruli
  • Pars radiata

Question 8

Medulla renalis

Answer 8

• Divided into:
  
  • External zone (dark color)
  • Internal zone (pale color)
• Pyramides renales
  
  • Basis pyramidis
  • Papilla renalis (bo, su)
  • Crista renalis (eq, ca)
  • Ductus papillares
  • Area cribrosa

Pyramides renalis:

• The pyramids consist mainly of tubules that transport urine from cortex renalis (where urine is produced) to the calyces, in which urine collects before it passes through the ureter
• Papilla renalis/crista renalis projects into calyx

Question 9

Functional unit of the kidney

Answer 9

• The functional unit of the kidneys are the:
  
  • Nephrons (responsible for urine production)
    
    • Glomerular capsule
    • Proximal convoluted tubule
    • Loop of Henle
      
      • ​Decending limb
      • U-turn
      • Ascending limb
    • Distal convoluted tubule
    • Collecting tubule​
• The collecting tubule approach papilla renalis, and are succeeded by papillary ducts which open on the surface of the papilla at tiny openings, papillary foramina, through which the urine enters pelvis renalis
• Aa. glomerularis afferens
  
  • ​Afferent vessels to the glomerulus from an a. interlobulares
• Aa. glomerularis efferens
  
  • ​Efferent vessel from the glomerulus to capillaries between tubules

Question 10

Pelvis renalis

Answer 10

• The proximal ureter begins with a expansion named pelvis renalis (ø bo)
• All the ductus papillaris open into pelvis renalis
• Pelvis renalis collects the urine, which reaches it through the papillary foramina, and conveys it into the ureter
• Location: within sinus renalis
  
  • ​But only fused with tissue around the papilla
• Pelvis renalis (ø bo)
  
  • ​Recessus pelvis (ca)
  • Calices renales (bo, su)
  • Recessus terminales (eq)
• Horse:
  
  • The renal pelvis consists of a central cavity and 2 recesuss terminales
  • ​Most of the ductus papillaris opens into recessus terminalis
• Carnivores:
  
  • Moulded around crista renalis
  • ​Extends ventrally and dorsally to form recessus pelvis
  • Separated by pseudopapillae and interlobular vesses
• Bovine:
  
  • Ø pelvis renalis
  • Calices renales formed by terminal branches of uteter
    
    • Uninte into 2 major channels, which converge from both poles of the kidney to form a single ureter
• Swine:
  
  • Calices renalis embrace an equal number of papilla renalis which protrude into pelvis renalis

Question 11

Draw the kidney

Answer 11

Question 12

Blood supply

Answer 12

• Aorta abdominalis
  
  • ​A. renalis (divides at the hilus renals)
    
    • ​A. interlobaris
    • ​A. arcuratae (curve over the base of pyramides renalis)
    • A. interlobularis
      
      • A. glomerularis afferens (enter corpuscula renis where it forms capillary loops of the glomerulus)
      • Glomerulus
      • A. glomerularis efferens (leaves the corpuscle and enters capillary network)
      • R. capsularis
      • Capillary plexus around the renal tubules
    • A. interlobularis
    • V. arcurata → venula stellatae (Ca, eq - capsular veins)
    • V. interlobaris
  • ​V. renalis → venae capsulares (Fe - joins v. renalis at hilus renalis)
• ​V. cava caudalis

Question 13

Innervation

Answer 13

• Plexus solearis: sympathetic and parasympathetic
  
  • ​Reach the kidney along a. renalis
• Sympathetic fibers from synapses in:
  
  • Ggl. celiacum
  • Ggl. mesentericum craniale
  • Plexus renalis (smaller ganglia)
• Parasympathetic:
  
  • ​N. vagus → r. dorsalis