Urinary System Flashcards
filters blood, eliminates nitrogenous wastes, and helps maintain the ion concentration of body fluids
urinary system
the major excretory organs in the urinary system
kidneys
bean shaped organs that lie against the dorsal body wall in a retroperitoneal position (behind the parietal peritoneum) in the superior lumbar region
they extend from the T12 to the L3 vertebra; thus they receive some protection from the lower part of the rib cage
kidneys
the kidneys filter blood and produce a large volume of filtrate
large molecules such as proteins, and blood cells remain the blood, whereas smaller molecules and ions enter the filtrate
excretion
as the filtrate flows through the kidneys, it is slowly modified until it is converted to ____________
urine
the kidneys play a major role in controlling the extracellular fluid volume in the body by producing either a large volume of dilute urine or a small volume of concentrated urine, depending on the hydration level of the body
regulation of blood volume and pressure
the kidneys help regulate the concentration of primarily the major ions like sodium, potassium, calcium, and bicarbonate
they also regulate other solute concentration such as urea
regulation of the concentration of solutes in the blood
the kidneys secrete variable amounts of hydrogen to help regulate the extracellular fluid acidity
regulation of extracellular fluid pH
the kidneys secrete the hormone ____________, which stimulates the synthesis of red blood cells in red bone marrow
erythropoietin
the kidneys play an important role in controlling blood levels of calcium by activating vitamin D
regulation of vitamin D synthesis
outer layer of connective tissue that surrounds each kidney
a thick layer of adipose tissue also cushions and protects the kidneys
renal capsule
a thin layer of connective tissue that surrounds the adipose tissue and helps anchor the kidneys to the abdominal wall
renal fascia
it is the medial indentation of the kidney where several structures including ureters, the renal blood vessels, and nerves, enter or exit the kidney
renal hilum
is just past the hilum of the kidney and is an internal space filled with loose connective tissue and adipose tissue, along with part of the renal pelvis, the calyces, and branches of blood vessels and nerves
renal sinus
outer region of the kidney where its blood-filtering structures are located
renal cortex
inner region of the kidney that surrounds the renal sinus
renal medulla
triangular shaped regions in the renal medulla which are a collection of tubes and ducts that transport fluid throughout the kidney and modify it into urine
once urine is formed, ducts in these transport it toward the renal sinus
renal pyramids
the tips of the pyramids that point toward the renal sinus
renal papillae
bases of the medullary pyramids that project into the cortex
medullary rays
extensions of the cortex that separates the medullary pyramids
renal columns
cup shaped areas that enclose the medullary pyramids and collect urine
calyces
small funnel shaped chamber surrounding the tip of the renal papilla collecting the formed urine
minor calyx
larger funnel shaped chamber where urine from several minor calyces are emptied
major calyx
single enlarged funnel shaped chamber that drains urine from the calyces to the ureters
it is embedded in and surrounded by the renal sinus
renal pelvis
the structural and functional unit of the kidney that forms the urine
nephron
filtration unit of the nephron and receives fluid from the blood
renal corpuscle
a cluster of capillaries where waste products are filtered from the blood
it is fed and drained by arterioles
glomerulus
the afferent arteriole is the feeder vessel and the efferent arteriole receives blood that has passed through the __________
glomerulus
thin membranous double walled capsule surrounding the glomerulus through which glomerular filtrate passes
Bowman’s capsule
a tube that connect from the bowman’s capsule where the fluid from the renal corpuscle travels
renal tubule
drains filtrate away from the renal corpuscle and returns filtered substances to the blood
proximal convoluted tube (PCT)
descends into the renal medulla and returns to the renal cortex, helps conserve water and solutes
loop of Henle
passes near the renal corpuscle then leads to a collecting duct that rids the blood of additional wastes
distal convoluted tubule (DCT)
receives the fluid from the renal tubules of several nephrons
urine from many of these empties into the funnel-like upper portion of the ureter called the renal pelvis
collecting duct
a tubule (larger diameter than the collecting ducts) located near the tip of the renal papilla where the collecting ducts merge and empties into the minor calyces
papillary duct
two types of nephrons
juxtamedullary nephrons
cortical nephrons
type of nephrons that have renal corpuscles that are found deep in the cortex near the medulla
they have long loops of Henle, which extend deep into the medulla
longer loops of Henle are well adapted for water conservation
juxtamedullary nephrons
type of nephrons that have renal corpuscles that are distributed throughout the cortex
their loops of Henle are shorter and are closer to the outer edge of the cortex
cortical nephrons
sometimes the flow of urine is blocked due to stones, infection, congenital abnormalities, or trauma
to restore the flow, a __________ __________ can be placed through the skin of the lower back into the kidney
as a result, urine will then drain into a small bag connected to the tube
nephrostomy tube
a procedure that uses shock waves to break up stones in the kidney and parts of the ureter
lithotripsy
a liquid waste formed by the kidneys from cleansing the blood
urine
urine consists of excess water, including the protein by-product called __________, and toxic substances
urea
color of urine
freshly voided urine is generally clear and pale straw to deep yellow
odor of urine
slightly aromatic
if allowed to stand, it takes an ammonia odor caused by the action of bacteria on the urine solutes
pH of urine
slightly acidic with a pH of 6
changes in the body metabolism and certain foods may cause it to be much more acidic or basic
constituents of urine
solutes like sodium, potassium, urea, uric acid, creatinine, ammonia, and bicarbonate ions are normally found in urine depending on the blood composition
when the nephrons exchanges materials with the blood along its entire length
urine formation
a nonselective, passive process in which fluid and dissolved substances from the blood enter the renal corpuscle forming the fluid filtrate
the filtrate is essentially blood plasma without blood proteins
both proteins and the blood cells are normally too large to pass through the filtration membrane
filtration removes only those substances small enough to fit through the filtration membrane
blood pressure drives substances across the capillary walls into the nephron
glomerular filtration
water, glucose, amino acids, ions, and other useful substances return to the blood from the filtrate
this takes place in the renal tubule and begins as soon as the filtrate enters the proximal convoluted tube
some reabsorption is done passively (osmosis) but most depend on active transport requiring ATP and are very selective
tubular reabsorption
where drugs, poisons, and hydrogen ions are secreted from the blood into the filtrate to be eliminated in the urine
this also takes place in the renal tubule
tubular secretion
it is a common type of indwelling catheter
it has soft, plastic, or rubber tube that is inserted into the bladder to drain the urine
Foley catheter
it provides a continuous infusion of sterile solution into the urinary bladder using a three-way irrigation system with a triple-lumen catheter, to remove loose tissue, clot and mucous shreds from the bladder
continuous bladder irrigation (CBI)
a narrow muscular tube where the urine from the kidney drains
waves of peristalsis squeeze the fluid along these into the urinary bladder
ureter
a smooth, collapsible saclike muscular organ that collects urine and stores it temporarily
it is located retroperitoneally in the pelvis just posterior to the pubic symphysis
urinary bladder
tube that carries urine by peristalsis from the bladder to the outside of the body
urethra
keeps the urethra closed when urine is not being passed
urethral sphincters
involuntary sphincter preventing urine leakage from the urinary bladder
internal urethral sphincter
voluntary sphincter allowing a person to start or stop the flow of urine through the urethra
external urethral sphincter
the act of voiding or urinating to empty the bladder
micturition
is a specialized regulatory structure formed by the distal convoluted tubule and the glomerular afferent arteriole
it is located next to the glomerulus and its main function is to regulate blood pressure and the filtration rate of the glomerulus
juxtaglomerular apparatus
are specialized secretory smooth muscle cells of the juxtaglomerular apparatus that secrete the hormone enzyme renin
juxtaglomerular cells
an enzyme secreted by the kidneys that participates in the body’s renin-angiotensin-aldosterone system (RAAS) that mediates the volume of extracellular fluid and arterial vasoconstriction to regulate blood pressure
also known as angiotensinogenase
renin
mechanism initiated under low blood pressure conditions that leads to the release of renin by the juxtaglomerular cells
renin-angiotensin-aldosterone-system (RAAS)
renin enters the blood and converts angiotensin, a plasma protein produced by the liver, to __________
angiotensin I
an enzyme produced by the lungs that converts angiotensin I to angiotensin II
angiotensin-converting enzyme (ACE)
it is a potent vasoconstricting hormone that increases peripheral assistance, causing blood pressure to increase
angiotensin II
angiotensin II also increases blood pressure by increasing the rate of ____________ ___________ which decreases sodium excretion, the sensation of thirst, salt appetite, and ADH secretion which raises water reabsorption in the kidneys
aldosterone secretion
