Final - Urinary Flashcards
urinary system
…specifically the kidneys maintain the purity and
chemical constancy of the blood and other extracellular body fluids
the kidneys filters
many liters of fluid from the blood, sending
toxins, metabolic wastes, excess water, and excess ions out of the
body in urine while returning needed substances back to the blood.
three main wastes products
urea
uric acid
creatine
the kidneys also regulate
the
volume and chemical makeup
of the blood
3 other parts of urinary system
paired ureters
urinary bladder
urethra
paired ureters
tube-like structure that transports urine from the
kidneys to the bladder
urinary bladder
: provides a temporary storage reservoir for urine
urethra
: tube-like structure that transports urine from the bladder out
of the body
the kidneys lie
“retroperitoneal” (behind the parietal peritoneum) in
the superior lumbar region of the posterior abdominal wall
the kidney extends
d from the level of the 11th/12th thoracic vertebrae to
the 3rd lumbar vertebrae
the right kidney
is crowded by the liver and lies` slightly inferior to
the left kidney
renal hilus
a vertical cleft located on the medial surface where renal
blood vessels, ureters, lymphatics and nerves enter and leave the
kidney
the several layers of supportive tissue surround each kidney
renal capsule
adipose capsulle
pararenal fat
renal capsule
A thin layer of dense C.T. adheres directly to the
kidney’s surface…maintaining its shape and forming a barrier that can
inhibit the spread of infection from the surrounding regions.
adipose capsule
Consists of perirenal fat and just external to that
is an envelope of renal fasci
pararenal fat
Lies external and mostly posterior to the renal fascia.
perirenal and pararenal fat layers function to
cushion the
kidney against blows
and help hold the kidney
in place.
frontal section shows two distinct regions of kidney tissue
cortex
medulla
kidney cortex
: The superficial cortex region is light in color and has a
granular appearance.
kidney medulla
Deep to the cortex is the darker renal medulla, which
consists of cone-shaped masses called medullary pyramids or renal
pyramids.
the broad base of each pyramid abuts the? and the pyraid’s apex points?
cortex
internally
renal columns
inward
extensions of the renal
cortex…separate adjacent
pyramids
the kidney has how many lobes?
5-11 lobes…each of which is a single renal pyramid
plus the cortical tissue that surrounds that pyramid.
renal sinus
large “filled space” within the medial part of the kidney
opening to the exterior through the renal hilus.
renal sinus contains
the renal vessels and nerves, some fat, and the urine
carrying tubes called the renal calices and renal pelvis.
renal pelvis
a flat, funnel-shaped expansion of the ureter
branching extention of the renal pelvis form
m two or three major
calices…each of which divides to from several minor calices, cupshaped
tubes that enclose the papillae of the pyramids
renal path
Renal papillae → Minor calyx → Major calyx → Renal pelvis → Ureter
→ Bladder → Urethra → Outside of body
uriniferous tubules
are the main structural and functional unit of
the kidney.
uriniferous tubules are composed of
nephron
collecting duct
nephron consists of
Renal corpuscle, a
proximal convoluted tubule, a loop of Henle, and a distal
convoluted tubule
collecting duct
involved in concentrating
urine by removing water
from it
the uriniferous tubule is lined by?
a simple epithelium
urineferous tubules produce
urine though three interacting mechanisms: filtration reabsorption secretion
filtration
a filtrate of the blood
leaves the kidney capillaries and
enters the nephron
reabsorption
most of the nutrients, water, and essential ions are recovered from the filtrate and returned to the blood of capillaries in the surrounding connective tissue.
secretion
The remaining wastes
contribute to the urine that leaves the
body.
a nephron is
the basic structural and functional unit of the kidney.
nephron chief function
to regulate the concentration of water and soluble
substances like sodium salts by filtering the blood, reabsorbing what
is needed and excreting the rest as urine
renal corpuscle
The first part of the nephron, occurs strictly in the
cortex
renal corpuscle consists of
a tuft of capillaries called
a glomerulus plus a glomerular
capsule (Bowman’s capsule).
the purpose of the renal corpuscle is
to extract the renal filtrate (it is not yet
to be called urine) from blood.
the glomeral endothelium is
fenestrated allowing large quantities of fluid and small molecules to pass from the capillary blood into the hollow interior of the glomerular capsule…the capsular space.
glomerulus
The minute convoluted capillary network in between the afferent arteriole and the efferent arteriole.
the glomerulus is contained within
the
Bowman’s capsule
(glomerular capsule)
bowman’s capsule (aka glomerular capsule)
an expanded end of
the renal tubule.
-It contains the glomerulus (capillary network).
the inner layer and outer layer of bowman’s capsule
-The inner layer is very porous to extract and absorb plasma from the
glomerulus.
-The outer layer is impermeable to contain the plasma that has been
extracted
renal tubule
a) proximal convoluted tubule, b) loop of Henle, c)
distal convoluted tubule and d) collecting tubule.
proximal tubule
composed of cuboidal cells with numerous
microvilli and mitochondria; reabsorbs water and solutes from filtrate
and secretes substances into it the Loop of Henle
- Confined entirely to the renal cortex
the loop of henle
is the portion of the nephron that leads from the
proximal convoluted tubule to the distal convoluted tubule. The
loop has a hairpin bend in the renal medulla
main function of looop of henle
to reabsorb water and ions
from the urine
distal convoluted tubule
cuboidal cells without microvilli that
function more in secretion than reabsorption
- Confined to the renal cortex.
the collecting duct system receive urine from
several nephrons and
runs straight through the cortex into the deep medulla
the collecting duct system concentrates urine
ADH hormone increases permeability of the
collecting tubules and distal tubules to water
at the apex of the pyramid
, adjacent collecting tubules join to form
larger papillary ducts, which empty into the minor calices
the two categories of nephrons divided according to location
cortical nephrons
juxtamedullary nephrons
cortical nephrons
85% of nephrons; located in the cortex (except
for a small part of the Loop of Henle that dip into the medulla)
juxtamedullary nephrons
15% are located at the cortex-medulla
junction, have loops of Henle that deeply invade the medulla, have
extensive thin segments, are involved in the production of
concentrated urine
afferent arterioles
are a
group of blood vessels that
supply the nephrons in many
excretory systems
afferent arteriole branch from
the renal artery and feed
the glomerular capillaries.
which has larger diameter? afferent or efferent arteriole
afferent arteriole
efferent arteriole
The arteriole that carries the concentrated blood (more cells, less plasma) away from the glomerulus and to the peritubular capillaries
peritubular capillaries
The network of low pressure and porous capillaries that surround lie in the interstitial C.T. of the renal cortex, clinging closely to the convoluted tubules and empty into nearby venules
function of peritubular capillaries
reabsorb some of the
nutrients and plasma that were
extracted in the Bowman’s
capsule
vasa recta
: hairpin looping vessels that descend into the medulla,
running alongside the loops of Henle
the right and left ureters
are muscular ducts (~10 inches) that
propel urine from the kidneys to the urinary bladder.
ureters begin.
-Each begins at the level of L2, as a continuation of the renal pelvis. -Descends retroperitoneally through the abdomen and enters the bladder through the posterior wall
the distal ends of ureters
close in
response to any increase of
pressure with in the bladder to
prevent backflow of urine
three basic layersof ureters
mucosa
muscularis
adventitia
mucosa
ureters
\: composed of a transitional epithelium that stretches when the ureters fill with urine and a lamina propria composed of a stretchy, fibroelastic C.T
muscularis
ureters
\: consists of two layers…an inner longitudinal layer and an outer circular layer of smooth muscle
adventita
ureters
external wall
made up of a typical C.T
ureters actively
propel urine to the bladder via response to smooth
muscle stretch
urinary bladder
smooth, collapsible, muscular sac that temporarily
stores urine (up to 1000 ml = 1 liter)
-It lies retroperitoneally on the pelvic floor posterior to the pubic
symphysis
urinary bladder position male and female
- Males: prostate gland surrounds the neck inferiorly
- Females: anterior to the vagina and uterus
trigone
triangular region on the posterior wall outlined by the
openings for the ureters and the urethra
-Clinically important because infections tend to persist in this region
the three layers of the walls of the bladder
mucosa
muscular layer
adventitia
bladder mucosa
transitional epithelium and a lamina propria
bladder muscular layer
thick detrusor muscle; consist of smooth muscle fibers arranged in inner and outer longitudinal layers and a middle circular layer…Contraction squeezes urine from the bladder during urination
bladder adventitia
fibrous ct
the bladder is
s distensible and collapses when empty
• As urine accumulates, the bladder expands without significant rise
in internal pressure
urethra
is a thinwalled
that drains urine from
the bladder and conveys it out
of the body
urthra has
excretory function in both sexes to pass urine to the outside, and also a reproductive function in the male, as a passage for semen.
sphincters keep the urethra
a closed when urine is not being passed
internal urethral sphincter
: involuntary sphincter at the bladderurethra
junction
external urethral sphincter
: voluntary sphincter surrounding the
urethra as it passes through the urogenital diaphragm
levator ani muscle
voluntary urethral sphincter
the lenght and functions of urethra differ in?
two sexes
male and female
female urethra
: the urethra is just 1.5 inches longmand isbound to the
anterior wall of the vagina by C.T.
- The urethra opens to the outside at the external urethral orifice.
males urethra
the urethra is about 8 inches and three named regions
prostatic urethra
membranous urethra
spongy(penile) urethra
prosttic urethra
2.5 cm
long and runs in the prostate
gland
membranous urethra
2.5
cm long and runs through the
urogenital diaphragm
spongy (penile) urethra
15 cm long, passes through the entire penis. and opens at the tip of the penis via the external urethral orifice
micturition
- voiding or urination
the act of emptying the bladder
-Caused by the contraction of the bladder’s detrusor muscle, assisted
by the muscles of the abdominal wall.
micturition controlled by?
the brain… Distension of bladder walls stimulates stretch receptors that initiate spinal reflexes at the sacral region that stimulate contraction of the external urethral sphincter and inhibit the detrusor muscle and internal sphincter (temporarily)
