Renal Anatomy & Histology Flashcards
Kidneys are considered retroperitoneal. What does this mean
They lie behind the peritoneal membrane that separates them from the internal abdominal organs
What level do the kidneys sit at
About T12 - L3
Which kidney is lower
The R
Define the renal hilum
This is the entrance to the renal sinus which contains the blood vessels, renal pelvis, and nerves
The left kidney hilum is located where
At transpyloric plane (T12)
The transpyloric plane runs through what on the right kidney
The superior pole of the R kidney
Define the anatomical position of each ureter
5 cm from the spinal column and intersects with transverse processes of lumbar spine
What is the purpose of the renal fascia
Sends collagen bundles throughout paranephric fat to hold kidney in place
Superiorly, what is the renal fascia continuous with
The inferior fascia of the diaphragm
Which N.’s pass diagonally across the posterior surface of the kidneys
Subcostal N.
Iliohypogastric N.
Iliolingual N.
What separates the R kidney from the liver
Hepatorenal recess
What is the order, anterior to posterior of the vessels in the renal hilum
Renal V. To Renal A. To Renal Pelvis
Define the renal capsule
Denser irregular CT on the surface of the kidney with an inner layer of myofibroblasts
Define the renal cortex
Outer portion containing renal corpuscles
Define the renal medulla
Collection of renal pyramids and columns
Define renal columns
Tissue lying between pyramids running from cortex to the calyx
Define renal lobes
Single pyramids plus the surrounding adjacent cortex
Define renal papillae
Projections of medullary pyramids apices into calyxes
The ureters have three constriction points what are they
At the renal pelvis
At the pelvic inlet
Passing into the urinary bladder
What is the major attachment of the adrenal glands
The diaphragm
What does the R suprarenal gland connect with
The IVC (ant/medially) The liver (ant/laterally) The diaphragm (superiorly)
Where do the veins and lymph enter into the suprarenal gland
The hilum
What is the major A. That supplies the ureters
The renal branches
What are the two parts of the suprarenal gland
- Suprarenal cortex
2. Medulla
Describe the suprarenal cortex
Arises from mesoderm
Secretes corticosteroids and androgens
Causes kidney to retain Na and H2O
Describe the suprarenal medulla
Mass of nervous tissue derived from NC cells
Does the whole NE thing
Where do the renal artery branch into segmental A.’s
At the hilum
What does the segmental A. Supply
Whole branches of the kidney
Where does the interlobar A. Pass between
Lobes of the kidney
Where does the arcuate A. Run
Over top of the renal pyramid
Where does the cortical radiate A enter
The cortex
Where does the Renal A. Arise from
L1/L2
Where does the venous drainage of the ureters drain into
Drains into the gonadal V.’s
Which sympathetic N.’s synapse at the aorticorenal ganglia and then into the kidneys
Lesser splanchnic N. (T10/11)
Least splanchnic N. (T12)
Lumbar splanchnic N. (L1/2)
What is the parasympathetic innervation of the kidneys
The Vagus N.
What is the urine forming unit of the kidney and what does it consist of
The nephron which consists of renal corpuscle and renal tubules
Define the medullary ray
A vertical column of straight collecting ducts consisting of the
Proximal straight tubule
The ascending loop of Henle
The cortical collecting duct
What does the cortex contain
Renal corpuscles
Convoluted and straight tubules
Portions of the collecting ducts
What does the medulla contain
Renal columns and renal pyramids
What is the role of the renal interstititum
Fibroblasts producing EPO which depends on O2 levels
Define the glomerulus
A collection of capillaries which are fenestrated with open pores
What is the parietal layer of Bowman’s capsule made up of
What about the visceral layer and the glomerular space
P - Simple squamous epithelium
V - podocytes
GS - primary filtrate
What is the origin of the proximal convoluted tubule
The urinary pole
What is contained in the vascular pole
The afferent and efferent arterioles
What does the R suprarenal V. Drain into
What about the L suprarenal V
The IVC
The L renal V.
Does the SNS N. To the suprarenal glands have a pre/post synaptic N? Explain
NO. Passes through aorticorenal plexus and synapses directly on to the chroffamin cells with a pre-synaptic N.
What does the glomerular endothelium contain
Truly open fenestrations and aquaporins
What is the role of the glycocalyx
Has a negative charge which repels anions
What can the glomerular endothelium generate and what is the significance of this
NO and PGE2 which is influenced by Ang. II and can help retain H2O
What is the physiological purpose of the podocytes (visceral layer of bowman’s capsule)
A single layer of cells having pedicles that make filtration slits with ultrathin diaphragms to allows for selectivity of filtration
Define the basement membrane and its function
A fused basement membrane of the endothelium and podocytes
Restricts passage of blood cells, Ig, and large proteins into the filtrate
What type of collagen makes up the basement membrane
Type 4 and 18
Does the basement membrane allow passage of albumin?
No
Define mesangial cells and their function
Support the glomerular loops and ECM of the podocytes
Also phagocytosis proteins and cellular debris
Also prevents glomerular distention due to high glomerular BP
Where is the PCT only found
In the renal cortex
The PCT is the most active tubule in what
Resorption and secretion
What cell types makes up the PCT
Simple cuboidal/columnar epithelium with a brush boarder
What does the PCT resorb most of
Glucose and AA
What does the PST contain
High-affinity Na/Glu co-transporters to get what glucose and Na are missed by PCT
Where does the loop of henle terminate near
The vascular pole
Define the make up of the TDLoH
Thin permeable simple squamous epithelial wall with no brush border
Define the make up of the ThALoH
Simple cuboidal epithelium with numerous microvili but no brush border
What is the role of the LoH
To set up the hyperosmotic gradient and retain fluids
Where is the DCT located
In the cortex
What makes up the DCT
Simple cuboidal epithelium
What influences Na resorption in the DCT
Aldosterone
What are the collecting ducts lined with
Simple cuboidal epithelium with simple columnar at their ends
What is the primary function of the collecting ducts
Water reabsorption
Final urine osmolality is determined by what
Resorbing water
What are the two cell types of the collecting duct epithelium
Light cells (principle cells) Dark cells (intercalated cells)
What targets the principle cells
Aldosterone
What is the function of the intercalated cells
H and bicarb trasnsport
What are the two capillaries that the efferent arterioles can give rise to
Peritubular capillaries and vasa recta
Define the peritubular capillaries
Surround the convoluted tubules and are lined with fenestrated endothelium
Define the vasa recta
Thin walled vessels that line the descending LoH and are part of the urine concentrating system
Define the JG cells
Mechanosensory cells which secrete renin if blood pressure is low
Define the macula densa
Cells at the distal end of ThALoH which act as chemoreceptor by monitoring salt levels and signal the JG cells to secrete renin if needed (Na Low)
What lines most of the urinary tract
Transitional epithelium
What are the three layers of the transitional epithelium of the urinary tract
Superficial (stretch and relaxed)
Intermediate (sliding)
Basal (stem cells)
What is the purpose of the fusiform vesicles
Adds plasma membrane to superficial epithelial cells to allow for stretch
What is the purpose of the intermediate layer
To allow the superficial layer to stretch and contract as needed with the volume of urine
What are the three layers of the ureter
Inner longitudinal
Outer circular
Outer longitudinal
Define the trigone
Inferior/posterior wall where ureters and urethra open
What is the bladder wall lined with
Transitional epithelium
What are the three layers of thick muscle called in the bladder
The detrusor muscle
Majority of the urethra is composed of what cell type
Pseudostratified columnar
What cell type is found at the distal end of the urethra
Stratified squamous epithelium
Females only have what type of urethra
Membranous
Define the control and make up fo the internal and external urethral sphincters
Internal - involuntary smooth muscle that is part of the bladder wall
External - voluntary skeletal muscle which inhibits urination and is part of the pelvic floor
What are the three regions of the male urethra and where do they lie
- Prostatic urethra - passes through prostate gland
- Membranous urethra - passes through urogenital diaphragm
- Spongy urethra - passes though the corpus spongiosum
The suprarenal A.’s arise from what three sources
Superior suprarenal A. From the inferior phrenic A.
Middle suprarenal A. From the abdominal aorta
Inferior suprarenal A. From the renal A.
What are the three A.’s of the suprarenal gland
Superior, middle, and inferior suprarenal A.’s