Renal histology Flashcards
List the functions of the kidney and urinary tract
Maintains water and electrolyte homeostasis
Acid-base homeostasis
Excretion of toxic metabolic products
Endocrine gland producing renin and erythropoietin
Where do the kidneys lie with respect to the peritoneum?
Retroperitoneal
What is the kidney capsule made of?
Dense collagen fibres
Name the contents of the renal hilum
Renal artery
Renal vein
Ureter
List the structure which come between the nephron and the bladder
Nephron > minor calyx > major calyx > renal pelvis > ureter > bladder
What are the two main layers of the kidney?
Cortex
Medulla
What lies within the medulla?
Renal/medullary pyramids with papillae
What are the renal columns? What is there function?
Medullary structures that lie inbetween the renal pyramids providing anchorage and pathways for vasculature
What are the two parts of the nephron?
Corpuscle
Tubules
What is the functional unit of the kidney called?
Nephron
What are the structures of the renal corpuscle?
Glomerulus (capillaries)
Bowman’s capsule
Afferent arteriole
Efferent arteriole
What type of cells is Bowman’s capsule composed of?
Squamous epithelium
Which two layers separate the blood from the glomerular filtrate? What are the special features of each?
Endothelium (fenestrated)
Podocytes (interdigitated processes form filtration slits)
Between the layers which separate the blood from the filtrate there is an abnormally thick structure, what is it?
Basal lamina
What do mesangial cells produce and what is there function?
Mesangium (connective tissue)
Support and removal of debris
What are the vascular and urinary poles of the corpuscle respectively?
Vascular pole is at the end of the corpuscle containing the capillary
Urinary pole is at the end of the corpuscle containing the tubules
What accumulates in bowman’s space and the tubules?
Urinary filtrate
Which type of cells line the proximal convuluted tubule and which specialised feature do they possess?
Columnar epithelium
Microvili (brush border)
Do the renal tubules possess many or few mitochondria?
Many
Is the diameter of the loop of Henle thicker or thinner than that of the proximal/distal tubules?
Descending limb is thin
Ascending limb is thick
What does the loop of Henle do and why?
Changes the osmotic pressure in the surrounding renal medulla to change urinary output
Where are the proximal/distal tubules and loop of Henle in relation to the kidney layers?
Proximal/distal tubules - cortex
Loop of Henle - medulla
Which two types of cells compose the loop of Henle?
Descending limb - squamous
Ascending limb - cuboidal
What is the vasa recta and how is it arranged within the kidney?
Small blood vessels
Begin in cortex –> loop down into medulla –> ascend back into cortex
Where are the proximal and distal convoluted tubules found with respect to the kidney layers?
Cortex
Which cell composes the distal convoluted tubule? What feature do these cells lack?
Cuboidal epithelium
No microvilli
Where are the collecting ducts found in relation to the layers of the kidney?
Cortex and medulla
What are medullary rays?
Straight segments of the collecting ducts, proximal and distal tubules which run perpendicular to the surface of the kidney
Which cells compose the collecting ducts?
Columnar epithelium
Which two structures are associated with the collecting ducts in the medulla of the kidney?
Loop of Henle
Vasa recta
What name is given to the most distal part of the collecting duct system?
Ducts of bellini/papillary ducts
What is the juxtaglomerular apparatus?
Portion of the distal convoluted tubule that loops back round to pass by the vascular pole of that same nephrons corpuscle
Name the three structures of the juxtaglomerular apparatus
Macula densa
Juxtaglomerular cells
Extraglomerular mesangial/lacis cells
What is the function of the macula densa?
Senses the ionic composition of the distal convoluted tubule
What is the function of the juxtaglomerular cells?
Contain and secrete renin
What is the function of lacis cells?
Unkown
Are macula densa cells found near the afferent or efferent arteriole?
Afferent arteriole
What type of cells compose the conducting portions of the urinary tract?
Urothelium/transitional epithelium
Describe typical urothelium
Stratified
Contains domed umbrella cells
Why is the urothelium arranged the way it is?
Variability in cell thickness - represents different states of distension
Thickened apical membrane (dome) - highly impermeable barrier
The urothelium is surrounded by lamina densa and smooth muscle. T/F
False - lamina propria and smooth muscle
What changes does the structure of the ureter undergo as it moves distally?
Thicker smooth muscle layer
Thinner connective tissue layer
How does the epithelium of the female urethra change as it moves distally?
Transitional to stratified squamous distally
How does the epithelium of the male urethra change as it moves distally?
Prostatic urethra - transitional
Membranous urethra - transitional to columnar
Penile urethra - columnar to stratified squamous
Describe the histology of the prostate gland
Tubo-alveolar glands lined by columnar secretory epithelium
Fibromuscular stroma
Prostatic secretions compose around half of the seminal fluid volume. T/F
True
