Urinary System Pt 1 Flashcards
The kidney has several important homeostatic, hormonal, and metabolic
functions that include:
The maintenance of water and electrolyte homeostasis.
* Regulation of acid-base balance in conjunction with the respiratory system.
* Excretion of metabolic waste products, especially the toxic nitrogenous
compounds.
* Production of renin for blood pressure control and erythropoietin, which
stimulates red blood cell production in the bone marrow.
* Conversion of vitamin D into active form for the regulation of calcium
balance.
_____ arterioles drain
the glomeruli & form
capillary networks
Efferent
? Drain cortical nephrons
and form _____ take
up substances resorbed
by tubular epithelium)
peritubular
capillary network
(nephron) Two main components; ____) &
____
renal
corpuscle (filters blood plasma & renal tubule (modifies filtrate to
form urine)
Two main components; renal
corpuscle (filters blood plasma) &
renal tubule (modifies filtrate to
form urine)
*?
functional unit of the kidney
nephron
(filters blood plasma/filters fluid from blood)
renal
corpuscle
(modifies filtrate to
form urine)
renal tubule
nephron: Parts are modified for
specific ____
functions
physiological
(nephron)
____– can be
subcapsular (short loops)
or midcortical
(inetermediate)
Cortical
Juxtamedullary (long)
*
Role of the ____: Maintenance of internal fluid
composition and volume (internal environment)
Kidneys
Tuft of fenestrated capillaries - the glomerulus; Surrounded by ____
urinary (Bowman’s) capsule
(renal corpuscle) Capillaries invaginate into Bowman’s capsule.Capillaries are in contact with the _______
visceral layer (podocytes).
Secrete the mesangial matrix as well
as vasoactive factors and
cytokines.
Mesangial Cells
Main structural
components of the mesangial matrix are:
collagen type IV, laminin,
fibronectin and proteoglycans.
The primary phagocytic function of
mesangial cells is to remove
_____from the basement
membrane thus keeping the filter
free of debris.
trapped residues and aggregated
protein
The contractile properties of
mesangial cells have been
suggested in changing the ____ of the glomerulus.
filtration
pressure
Fluid from ____ leaks into the urinary space through a
complex filtration barrier
capillaries
Fluid from capillaries leaks into the urinary space through a
complex filtration barrier
1. Fenestrated capillary endothelium
2. Basal lamina (basement membrane)
3. Podocytes of the visceral layer of Bowman’s capsule
Filtration barrier
High ____ charge on some components of both basal
lamina (glycoprotein podocalyxin) and surface of podocyte
processes
polyanionic
Fenestrated
●Large pores not covered by
a diaphragm
●Permeable to water, urea,
glucose & small proteins
●Barrier only to formed
elements in blood & large
macromolecules
Glomerular capillaries
____ contains:
Type IV collagen
Laminin
Fibronectin
Negatively-charged
proteoglycans
Lamina rarae
Each pedicel has a
glycocalyx of
_____-charged
podocalyxin
negatively
(Each Pedicels) Separated by clefts
___
filtration slits
(Each Pedicels) Covered by a porous
slit diaphragm made
of protein ____
nephrin.
(Each Pedicels Acts as additional
barrier to large
macromolecules,
proteins, negatively
charged molecules &
blood cells.
Podocytes have
_____ functions.
phagocytic
Describe the filtration process:
Blood enters glomerulus via afferent arteriole
●Arteriole pressure forces fluid through fenestrae of
capillary endothelium
● Large molecules are trapped by the basal lamina
●Negatively charged molecules are stopped by the
basal lamina & podocytes
●Fluid passes though pores in slit diaphragm to
enter the urinary space ➔ PCT.
Site of “Bulk Operations”, it
begins at urinary pole. Primary
site of water resorption,
removes 75% of water and ions
(Na, Cl)
Proximal Convoluted Tubule (found only in cortex)
Extensive reabsorption of
glomerular filtrate (microvilli).
NA+ (active transport)
Cl- (passive diffusion)
H20 (AQP-1, aquaporin-1)
small transmembrane channel
proximal tubule
