1 Urinary System Flashcards
does the urinary system have exocrine and endocrine functions?
Yes
[filters, stores and excretes……conserves salts, glucose, proteins, and H2O to regulate BP and influence acid-base balance]
What are the 2 major functions of the kidney/nephron?
Homeostasis and secretion of hormones
What is maintenance of a stable extracellular environment for normal cell function?
Homeostasis
What are the 3 main processes by which urine formation is controlled?
Filtration, secretion, reabsorption
Where is the formation of urine specifically controlled by?
nephron
Where is blood plasma selectively filtered?
glomerulus
What contains the waste products of metabolism dissolved in water? Where does it enter?
glomerular filtrate
enters kidney tubules
What modifies the filtrate by transferring substances from surrounding capillaries into the fluid?
tubules of the nephron
What does secretion of substance into nephron tubules play an important role in maintaining?
- potassium balance [remove excess]
2. Acid-base balance [remove excess H and NH4]
What does reabsorption in the nephron tubules play a major role in maintaining?
- extracellular fluid volume and BP
- Water conservation
- Sodium Balance [bring back to blood]
What is produced in kidneys, protease, participates in regulation of blood pressure?
Renin-[renin-angiotensin-aldosterone system]
What is produced in the kidney and stimulates production of RBCs?
erythropoietin
What structures are in the kidney hilum?
renal artery
renal vein
renal pelvis
ureter
What is the external connective tissue layer of the kidney?
renal capsule
What is the outer reddish brown part of the kidney?
cortex
what is the inner segmented part of the kidney?
medulla
what is the region of the medulla that projects into a minor calyx?
papilla
what are numerous narrow tributaries that drain urine away from each papilla?
minor calyx
What consists of a renal pyramid and half a renal column on each side and a cortex base and renal papilla apex?
renal lobe
what extends into medulla to create a renal column?
cortex
what are the tiny holes in the renal papilla called?
area cribrosa
What is the functional unit of the kidney and responsible for the production and modification of urine?
uriniferous tubule
What are the 2 embryologically distinct components of the uriniferous tubule?
nephron and collecting duct
What embryological origin is the nephron from?
metanephros
What is the collecting duct derived from?
ureteric bud
T-F–vessels in the kidney are often named according to their location within the kidney?
true
Is the kidney well insulated?
yes
This is a slide to review blood flow through the kidney, if you think you can handle it please try if not just read it. There will be some short questions later about it…what is the path flow in the kidney starting with the renal artery?
renal a.–>segmental a.–> interlobar a. –> arcuate a.–> interlobular a. –> afferent arteriole –> glomerulus –> efferent arteriole –> peritubular capillaries (around convoluted tubulues) –> vasa recta (around loop of hence) -> inter lobular vein –> arcuate vein –> inter lobar vein –> renal vein
Are their 2 inter lobar artery portions?
No, it is inter lobar first then after arcuate there is interlobular
Does the arcuate a. come before the segmental artery?
No
What is a renal lobule centered about? what are they flanked by?
medullary ray and is flanked on each side by interlobular arteries
What is a series of straight collecting ducts that extend from cortex into medulla and drain a collection of nephrons?
medullary ray
What are branches of arcuate arteries that supply the renal cortex?
interlobular artery
What are the contents of the renal corpuscle?
glomerulus engulfed by bowman’s capsule [nephron]
T-F—the afferent arteriole is wider than the efferent?
True
what is CT around the arterioles that does not enter glomerulus replaced by? 2 roles?
mesangial cells [phagocytic and contractile]
Are endothelial cells of the glomerulus fenestrated?
yes 70-90 nm
What is the order of basal lamina layers of glomerulus?
lamina rara interna [ endothelial]
lamina densa [thickest]
lamina rara externa [closest to podocyte]
what is the visceral layer of bowman’s capsules?
podocytes
What do primary process of podocytes give off?
pedicels—>interdigitate
What are the spaces between pedicels called?
filtration slits 20-40 nm wide
What is a thin membrane that spans adjacent pedicels—what does it contain?
slit diaphragm—pores called nephrons
what is parietal layer of bowman’s made of?
simple squamous epithelium
What is the filtrate volume reduced by in the proximal convoluted tubule? what is absorbed? what is diffused?
75%
Na absorbed
Cl diffused
What is the epithelial layer of the proximal convoluted tubule? what may distinguish them in histo?
- simple cuboidal with microvilli
- large cells and section may miss nucleus
What is the diff in epithelium of thick and thin loop of henle
thick-simple cuboidal
thin- simple squamous
What plays a huge role in making urine hypertonic?
nephron—conserves water
What is responsible for absorption of Na and secretion of K through sodium pumps in its epithelial cells and regulated by aldosterone?
distal convoluted tubule- maintain body’s water-salt balance
What secretes H and NH4 in urine to help maintain acid- base chemistry?
distal convoluted tubule
Key histo features of distal convoluted tubules?
simple cuboidal few microvilli
small cells —all nuclei present
short
When is the collecting duct epithelium permeable to water?
PRESENCE OF ADH
What are the key histo features of the collecting duct?
simple cuboidal to low columnar
cells bulge into large lumen
large central nucleus
prominent intercellular boundaries
What do numerous collecting ducts converge into?
ducts of bellini
what is the epithelium of ducts of bellini?
simple columnar epithelium
The juxtaglomerular apparatus contains what 3 types of cells?
- macula densa
- extra-glomerular mesangial cells
- juxtaglomerular granular cells
What do macula dense cells do in response to High Na levels?
release vasoactive compounds to mesangial cells that then contract
what are modified smooth muscle cells of the afferent arterioles that contain zymogen and rich sympathetic innervation?
juxtaglomerular cells
What leads to increased autonomic stimulation of the JG cells and cause them to release renin?
decreased arterial blood pressure
What does renin cleave?
angiotensinogen
What does angiotensin II do in the adrenal glands?
cause release of aldosterone
What does aldosterone promote?
Na and water reabsorption from the DCT into peritubular capillaries
What type of epithelium is in the excretory passageways?
transitional with a very elastic lamina propria
t-f—there is a thick zone of smooth musclee to transport urine through lumen?
T- muscularis externa
What else does the bladder have along with the dense irregular CT adventitia?
serosa
How do the ureters enter the walls of the bladder to prevent back flow?
sharply oblique
What part of the bladder is not folded?
trigone
How many muscle layers of bladder?
3 interlaced
what are the names of the sections of male urethra?
prostatic, membranous, spongy
What type of epithelium is membranous portion of urethra?
stratified columnar and patchy pseudo stratified columnar
what type of epithelium in the spongy urethra?
stratified squamous non-keratinized
