Unit 16: Urinary System Flashcards
(30 cards)
What are the main structures of the urinary system?
2 Kidneys
2 Ureters
Urinary bladder
Urethra
What are the functions of the urinary system?
Regulates: blood volume/pressure,
pH, concentrations of each ion in the blood (H+, Ca++, K+, Cl-)
Eliminates: wastes, hormones,
drugs, toxins
The kidneys are supported and protected by 3 layers of connective tissue. What are they?
Fibrous capsule (outer)
Perirenal fat capsule (middle)
Renal fascia (inner)
True or false: the kidneys are retroperitoneal organs
True
The _______ kidney is lower than the _______ kidney
right, left
The renal hilus (hilum) serves as the entry point of what?
Renal artery (superior)
Renal vein (inferior)
Ureter
Nerves
What is the renal cortex?
It is the superficial layer of the kidney that contains parts of nephrons, afferent and efferent arterioles, as well as capillary beds called glomeruli
The renal medulla (deep to cortex) contains renal pyramids and renal columns. Explain what these are
Renal pyramids: it contains parts of nephrons, and the apex of the pyramid is called the renal papilla
Renal columns: projections of the cortex into the medulla which separate the pyramids. They contain arteries, veins, and nerves that supply the cortex
This area is the central collecting chamber for filtrate/urine received by major calyces (in turn received through minor calyces which are small cup-shaped structures surrounding papilla)
The renal pelvis
What are the 4 components of the renal corpuscle in a nephron?
Glomerulus: capillary bed
Afferent arteriole: enters glomerulus and carries blood delivered to the kidney from the renal artery
Efferent arteriole: exits glomerulus and paritubular and vasa recta
Glomerular (Bowman’s) capsule: collects filtrate from glomerulus
What are the 2 layers that make up the glomerular (Bowman’s) capsule?
Outer layer: simple squa. epithelium
Inner layer: made of cells called podocytes that wrap around glomerular capillaries
The filtration membrane of the renal corpuscle consists of 3 layers. What are they?
Glomerular endothelium (capillaries): fenestrations (pores) allow plasma through
—shared basement membrane—
Podocytes: many finger-like projections that form a network of filtration slits
What are the 4 parts of renal tubules?
Proximal convoluted tubule (PCT)
Nephron loop
Distal convoluted tubule (DCT)
Collecting ducts
What structures can be found in the cortex area of the nephron? What about the medulla?
Cortex: proximal convoluted tubule (PCT), distal convoluted tubule (DCT)
Medulla: nephron loop
Both: collecting ducts
The proximal convoluted tubule (PCT) is made of cuboidal epithelium with dense microvilli. What function does the PCT perform?
Receives filtrate from the glomerular capsule and reabsorbs most useful substances whilst secreting waste products into the filtrate
What is the difference in the composition of the ascending and descending limbs of the nephron loop?
Descending: simple squa. epi., thin, highly water permeable
Ascending: simple cuboidal epi., thick, water-impermeable
These structures drain filtrate from numerous nephrons and contain cells that regulate water and Na+ reabsorption, as well as blood pH
Collecting ducts
What are the 2 types of nephron?
Cortical and juxtamedullary
Describe cortical nephrons (85%)
They sit near the surface of the kidney with short nephron loops that dip into the outer medulla. They have peritubular capillaries that surround the DCT and PCT
Describe juxtamedullary nephrons (15%)
Corpuscles in cortex near the medulla with long nephron loops that go deep into the medulla. Arterioles called vasa recta run parallel to nephron loop
What is the name for the point of contact between the end of the ascending limb, afferent, and efferent arterioles at the renal corpuscle at the same nephron?
The juxtaglomerular complex (apparatus). It regulates the rate of filtrate formation
What are the 2 main parts of the juxtaglomerular complex?
Tubular portion (macula densa): modified (tall/narrow) DCT cells that monitor filtrate comp.
Vascular (arteriolar) portion: afferent /efferent portion (granular). Modified smooth muscle cells that monitor blood pressure with enzymes and hormones
What structures does this describe:
Retroperitoneal structure that transports urine from renal pelvis to bladder
Ureters
What makes up the histology of the ureters?
Mucosa = transitional epi. (stretches)
Muscularis externa = smooth muscle
Adventitia = connects it to body wall
