Anatomy & Histo Flashcards
Which kidney is lower and why?
The right kidney because the liver
What are the three tissue layers that surround the kidney (not physically part of the kidney)?
From internal to external: Perinephric fat (perirenal fat capsule), renal fascia, and paranephric fat (pararenal fat body)
What is the outermost anatomic layer of the kidney what tissue/cells are found there?
Capsule
Outer surface is composed of dense irregular connective tissue (fibroblasts)
Inner surface is composed of myofibroblasts (contractile)
What do you call the outer portion of the kidney that contains renal corpuscles?
Renal Cortex
What do you call the inner portion of the kidney that contains the renal pyramids and columns?
Renal Medulla
What are renal pyramids?
Cone shaped masses in the medulla projecting into the calyx
What are renal columns?
Tissue lying between the renal pyramids that run from the cortex to the calyx
What does a renal lobe comprise of?
One renal pyramid plus the surrounding adjacent cortex
What is the portion of the kidney that acts as a funnel collecting urine?
Renal pelvis
What are renal calyxes?
Out-pocketings of the renal pelvis
What are the renal papillae?
The projections of the renal pyramids that connect with the calyxes.
List the Renal blood supply vessels in order
Aorta, Renal Artery, Segmental Artery, Interlobar Artey, Arcuate Artery, Cortical Radiate Artery, Afferent Arteriole, Glomerulus, Efferent Arteriole…
…then EITHER the Vasa Recta (vessels surrounding loop of henle) OR Peritubular Capilaries (vessels surround convoluted tubules)
…which reconnect at either the Cortical Radiate Vein or the Arcuate Vein,
Then Interlobar vein, renal vein, and inferior vena cava
What nerve(s) provide sympathetic innervation to the kidney and where do(es) it/they originate?
Lesser Splanchnic Nerve (T10, T11)
Least Splanchnic Nerve (T12)
Lumbar Splanchnic Nerves (L1-L2)
What nerve(s) provide parasympathetic innervation?
Vagus Nerve
List the segments of the nephron in order
Bowman’s capsule, Proximal Convoluted tubule, Proximal Straight Tubule, Thin Loop of Henle, Thick Ascending Loop of Henle, Distal Convoluted Tubule, Collecting Tubule, Collecting Duct, Papillary Duct
Where do the juxtaglomerular cells meet up with the nephron?
Thick Ascending Loop of Henle
What is the renal interstitium responsible for?
Fibroblasts secrete of erythropoietin
Where is the parietal layer found in the corpuscle and what cells is it composed of?
The outer layer of the Bowman’s capsule and simple squamous epithelium
Where is the visceral layer found in the corpuscle and what cells is it composed of?
Surrounds the glomerular capillaries and podocytes
What is special about the glomerular endothelium?
Fenestrations (small pores, some with diaphragms)
Thick luminal glycocalyx (glycoproteins, negatively charged)
Have lots of aquaporins
Generate PGE2 and Nitric Oxide
What function(s) does the glomerular basement membrane provide?
Provides a physical barrier as well as a chemical barrier
Physical barrier restricts movement of larger molecules
Chemical barrier (glycocalyx) is negatively charged and inhibits movement of negatively charged molecules (is anti-anionic)
What types of collagen make up the glomerular basement membrane?
Type IV and Type XVIII collagen
What is Albuminuria and what does it indicate?
Albumin proteins found in the urine.
Albumin is found in the basement membrane, so if you albumin is found in the urine, this means the glomerular basement membrane has taken damage.
What do messangial cells do?
- Support the glomeular capillaries
- Prevent glomerular capillary distension due to high bp
- Are phagocytotic, consume cell debris
- Secrete growth factors and cytokines in response to injury
- Can control GFR
What is the most abundant tubule?
Proximal Convoluted Tubule
What would you look for in order to recognize the Proximal Convoluted Tubule on a light microscope slide?
Simple cuboidal to columnar epithelium
Abundant microvilli (brush border)
Abundant Mitochondria
Basolateral membrane highly folded for increased surface area
What transporter proteins would you find in the basolateral proximal convoluted tubule?
Na-K-ATPase, Aquaporins, SGLT2, various glucose transporters, and amino acid transporters
What would you look for in order to recognize the Proximal Straight Tubule on a light microscope slide?
Not as tall as PCT and less prominent brush border
What transporter proteins does the PST contain?
High affinity sodium-glucose co-transporters (SGLT1)
What would you look for in order to recognize the Thin Limb of the Loop of Henle on a light microscope slide?
Thin permeable simple squamous epithelium LACKING a brush border
Some nuclei bulge into the lumen
What would you look for in order to recognize the Thick Ascending Limb of the Loop of Henle on a light microscope slide?
Simple cuboidal epithelium with numerous microvilli but no visible brush border
How do the functions of the Loop of Henle change as follow along its length?
The descending limb removes water from the lumen
The ascending limb removes salt from the lumen
What would you look for in order to recognize the Distal Convoluted Tubule on a light microscope slide?
Simple cuboidal epithelium with sparse microvilli
What hormones/signals have influence the DCT and what are the resulting effects?
Angiotensin II promotes Na+ reaborption
Parathyroid Hormone (PTH) promotes Ca2+ reabsorption
What would you look for in order to recognize the collecting duct on a light microscope slide?
Simple cuboidal epithelium, but simple columnar epithelium at their ends
What are the two cell types found in the Collecting Ducts?
Light Cells (principal cells) - have cilia; sensitive to aldosterone
Dark cells (intercalated cells) - do not have cilia; involved in H+ and HCO- transport
What hormones target the collecting ducts what are their effects?
Aldosterone - Increases Na+ reabsorption, Increases Potassium Secretion
Antidiuretic Hormone - Increases H2O permeability, thus increasing H2O reabsorption
What are the Peritubular Capillaries?
Vessels that branch from the Efferent Arterioles, which supply blood to the convoluted tubules.
Lined with fenestrated endothelium
What are the Vasa Recta?
Vessels that branch from the Efferent Arterioles, which supply blood to the loop of Henle and participate in the Counter-Current Mechanism.
Endothelium is continuous when descending, but is fenestrated when ascending
What are the juxtaglomerular cells and what do they do?
Juxtaglomerular cells are specialized sensory cells at the glomerulus.
They are mechanosensory cells that secrete Renin when the blood pressure is low or when signaled from the Macula Densa
Renin activates the RAAS system, resulting in increased Na+ retention, increased blood volume, and increased blood pressure
What is the macula densa?
Specialized chemosensory cells in the Thick Ascending Limb of the Loop of Henle.
They signal the Juxtaglomerular cells to secrete Renin when the luminal Na+ levels are low
What tissue lines the entire Urinary tract organs?
Transitional epithelium (from ureters to beginning of urethra)
What are the three layers of the transitional epithelium?
Superficial - stretches and relaxes
Intermediate - sliding layer
Basal - stem cells
What are fusiform vesicles and what is there purpose?
Vesicles that fuse with plasma membrane when cell is distended
Vesicles are endocytosed when cell is non-distended
What structures form an impermeable barrier in the transitional epithelium?
Urothelial Plaques
What are the tissue layers found in the ureter?
Transitional Epithelium Inner Longitudinal Muscle Outer Circular Muscle Outer Longitudinal Muscle Adventitia - connective tissue
Which urinary sphincter is voluntary and which is involuntary?
External urinary sphincter is voluntary
Internal urinary sphincter is involuntary
What are the three segments of the urethra?
- Prostatic Urethra - passes through prostate gland (male only)
- Membranous Urethra - travels through the urogenital diaphragm (both male and female)
- Spongy (penile) urethra - Passes through penis (male only)
