Urinary System Flashcards
Kidneys dispose of waste products in ?
urine
Kidneys dispose of waste products in urine (4)
- nitrogenous wastes
- toxins
- drugs
- excess ions
Kidneys’ regulatory functions include: (3)
- production of renin to maintain BP
- production of erythropoietin to stimulate RBC production
- conversion of vit. D to its active form
Organs of the Urinary System
Kidneys
Ureters
Urinary bladder
Urethra
The kidneys are situated against the dorsal body wall
in a ??? position
retroperitoneal
The kidneys are situated at the level of the ?? to ?? vertebrae
T12 to L3
The right kidney is slightly lower/higher than the left (because
of position of the ???)
lower;
liver
function of kidneys (5)
- blood waste elimination
- blood production
- blood volume regulation
- BP regulation
- bone density
vitamin D conversion by what organ first before kidney?
liver
test to identify how well the kidney filters waste
GFR, glomerular filtration rate
GFR: normal kidney funtion
90 ml/min
GFR: slight reduction of kidney function
60-89 ml/min
GFR: moderate function
30-59 ml/min
GFR: kidney injury
15-29 ml/min
GFR: kidney failure
<15 ml/min
An adult kidney size
about 12 cm (5 in) long and
6 cm (2.5 in) wide
A medial indentation where several structures enter or exit the kidney (ureters, renal blood vessels, and
nerves)
renal hilum
Three protective layers enclose the kidney
fibrous capsule
perirenal fat capsule
renal fascia
protective layer that encloses each kidney
fibrous capsule
surrounds the kidney and cushions
against blows
Perirenal fat capsule
is the most superficial layer that anchors the kidney and adrenal gland to surrounding structures
Renal fascia
Three regions revealed in a longitudinal section
renal cortex
renal medulla
renal pelvis
outer region (longitudinal)
renal cortex
deeper region (longitudinal)
renal medulla
triangular regions of tissue
in the medulla
renal (medullary) pyramids
extensions of cortex like material that separate the pyramids
renal columns
renal medulla (2)
renal/medullary pyramids
renal columns
medial region that is a flat, funnel
shaped tube
renal pelvis
form cup-shaped “drains” that enclose the renal pyramids
Calyces
collect urine and send it to the renal pelvis, on to the ureter, and to the urinary bladder for storage
Calyces
how much of the total blood supply of the body passes through the kidneys each minute?
One-quarter
provides each kidney with arterial blood supply
Renal artery
Renal artery divides into segmental arteries (3)
→ interlobar arteries
→ arcuate arteries
→ cortical radiate arteries
Venous blood flow (4)
Cortical radiate veins
→ arcuate veins
→ interlobar veins
→ renal vein
Is there or is there not segmental veins?
there is not
Renal vein returns blood to the ?
inferior vena cava
Structural and functional units of the kidneys
nephrons
Each kidney contains how many nephrons
over a million
Each nephron consists of two main structures
renal corpuscle
renal tubule
Renal corpuscle consists of (2)
glomerulus
glomerular (Bowman’s) capsule
a knot of capillaries made of podocytes
glomerulus
make up the inner (visceral) layer of the glomerular capsule
Podocytes
cling to the glomerulus
Foot processes
create a porous membrane—ideal for filtration
Filtration slits
is a cup-shaped structure that surrounds the glomerulus
Glomerular (Bowman’s) capsule
First part of the renal tubule
Glomerular (Bowman’s) capsule
how much nephrons does a human need to survive
800k
Extends from glomerular capsule and ends when it empties into the collecting duct
renal tubule
From the glomerular (Bowman’s) capsule, the subdivisions of the renal tubule are: (3)
- Proximal convoluted tubule (PCT)
- Nephron loop (loop of Henle)
- Distal convoluted tubule (DCT)
Cortical nephrons location
in the cortex
Include most nephrons
cortical nephrons
Found at the cortex-medulla junction
Juxtamedullary nephrons
Nephron loop dips deep into the medulla
Juxtamedullary nephrons
collect urine from both types of nephrons, through the renal pyramids, to the calyces,
and then to the renal pelvis
Collecting ducts
Two capillary beds associated with each nephron
- Glomerulus
- Peritubular capillary bed
Fed and drained by arterioles
glomerulus
arises from a cortical radiate artery
and feeds the glomerulus
Afferent arteriole
receives blood that has passed through the glomerulus
Efferent arteriole
Specialized for filtration
glomerulus
Glomerulus: what forces fluid and solutes out of blood and into the glomerular capsule
High pressure
Arise from the efferent arteriole of the glomerulus
Peritubular capillary beds
Low-pressure, porous capillaries
Peritubular capillary beds
Adapted for absorption instead of filtration
Peritubular capillary beds
Cling close to the renal tubule to receive solutes and water from tubule cells
peritubular capillary beds
peritubular capillary beds drain into the ?
interlobar veins
Urine formation is the result of three processes
- Glomerular filtration
- Tubular reabsorption
- Tubular secretion
water & solute force to capillary walls
glomerular filtration
water, glucose, and amino acid are reabsorbed
tubular reabsorption
waste being removed and secreted
tubular secretion
The glomerulus is a what
filter
Filtration is a nonselective passive process
Glomerular filtration
glomerular filtration: are normally too large to pass through the filtration membrane
Proteins and blood cells
glomerular filtration: Once in the capsule, fluid is called
filtrate
glomerular filtration: Filtrate leaves via the ???
renal tubule
filtrate will be formed as long as systemic blood pressure is ???
normal
If arterial blood pressure is ???, filtrate formation stops because glomerular pressure will be too low to form filtrate
too low
process: The peritubular capillaries reabsorb useful substances
from the renal tubule cells
tubular reabsorption
Tubular reabsorption
The peritubular capillaries reabsorb useful substances
from the renal tubule cells, such as:
Water
Glucose
Amino acids
Ions
Some reabsorption is ???; most is ???
passive;
active (ATP)
Most reabsorption occurs in the ?
proximal convoluted tubule
Reabsorption in reverse
tubular secretion
Some materials move from the blood of the peritubular capillaries into the renal tubules to be eliminated in filtrate
tubular secretion
(BUN)
Blood Urea Nitrogen
tubular secretion materials to be eliminated in filtrate
Hydrogen and potassium ions
Creatinine
Secretion is important for: (3)
- Getting rid of substances not already in the filtrate
- Removing drugs and excess ions
- Maintaining acid-base balance of blood
tubular secretion: Materials left in the renal tubule move toward the
??
ureter
poorly reabsorbed, if
at all; Tend to remain in the filtrate and are excreted from the
body in the urine
nitrogenous wastes
end product of protein breakdown; gives the smell of urine
urea
results from nucleic acid metabolism
uric acid
associated with creatine metabolism in muscles
creatinine
In 24 hours, about how many liters of urine are produced?
1.0 to 1.8
contains everything that blood plasma does
(except proteins)
Filtrate
is what remains after the filtrate has lost most of its water, nutrients, and necessary ions through reabsorption
Urine
contains nitrogenous wastes and substances that are not needed
Urine
color of urine
Clear and pale to deep yellow
Yellow color is normal and due to the pigment ?
urochrome
from the destruction of hemoglobin and solutes
urochrome
color of dilute urine
pale, straw color
when is urine sterile
at formation
Urine is slightly aromatic, but smells like ? with time
ammonia
pH of urine
Slightly acidic (pH of 6)
urine Specific gravity
1.001 to 1.035
Solutes normally found in urine (4)
Sodium and potassium ions
Urea, uric acid, creatinine
Ammonia
Bicarbonate ions
Solutes NOT normally found in urine (6)
Glucose
Blood proteins
Red blood cells
Hemoglobin
WBCs (pus)
Bile
test for renal calculi
gold flam’s test
Cloudy urine (with pus): sign of what
UTI
glucose in urine
glycosuria
proteins in urine
proteinuria (albuminuria)
pus (WBCs and bacteria) in urine
pyuria
RBCs in urine
hematuria
hemoglobin in urine
hemoglobinuria
bile pigment in urine
bilirubinuria
Slender tubes attaching the kidney to the urinary bladder
ureters
ureters measurement
25–30 cm (10–12 inches)
ureters are continuous with the
renal pelvis
ureters enter the?
posterior aspect of the urinary bladder
ureters run behind what
peritoneum
aids gravity in urine transport
Peristalsis
Smooth, collapsible, muscular sac situated posterior to the pubic symphysis
urinary bladder
Stores urine temporarily
urinary bladder
triangular region of the urinary bladder base based on three openings
trigone
trigone 2 openings from?
the ureters (ureteral orifices)
trigone 1 opening from?
the urethra (internal urethral orifice)
In males, ??? surrounds the neck of the urinary bladder
the prostate
Wall of the urinary bladder
Three layers of smooth muscle collectively called the
detrusor muscle
Mucosa of urinary bladder made of ?
transitional epithelium
Walls are ??? in an empty urinary bladder
thick and folded
can expand significantly without increasing internal pressure
Urinary bladder
A moderately full bladder is about ??? long and holds about ??? of urine
5 inches;
500 ml
anatomical capacity of bladder
1L
urge to urinate at how much urine in bladder?
200ml
opens when bladder expands and pressure opens sphincter (involuntary)
internal sphincter
voluntary sphincter
external sphincter
Thin-walled tube that carries urine from the urinary bladder to the outside of the body by peristalsis
urethra
urethra function in females:
carries only urine
urethra function in males:
carries urine and sperm
Release of urine is controlled by two sphincters
Internal urethral sphincter
External urethral sphincter
Involuntary sphincter and made of smooth muscle
internal urethral sphincter
Voluntary sphincter and made of skeletal muscle
external urethral sphincter
length of urethra in females
3-4 cm (1.5 in)
length of urethra in males
20cm (8 in)
urethra location for females:
anterior to the vaginal opening
urethra location for males:
travels through the prostate and penis
3 urethra in males
Prostatic urethra
Membranous urethra
Spongy urethra
Voiding, or emptying of the urinary bladder
micturition
transmit impulses to the sacral region of the spinal cord
Stretch receptors
Impulses travel back to the bladder via the ??? to cause bladder contractions
pelvic splanchnic nerves
When contractions become stronger, urine is forced past the ??? into ???
involuntary internal sphincter;
the upper urethra
The ??? is voluntarily controlled, so micturition can usually be delayed
external sphincter
Blood composition depends on three factors
- Diet
- Cellular metabolism
- Urine output
Kidneys have four roles in maintaining blood
composition
- Excreting nitrogen-containing wastes
- Maintaining water balance of the blood
- Maintaining electrolyte balance of the blood
- Ensuring proper blood pH
Normal amount of water in the human body: young adult females
50%
Normal amount of water in the human body: young adult males
60%
Normal amount of water in the human body: babies
75%
Normal amount of water in the human body: the elderly
45%
is necessary for many body functions, and levels must be maintained
Water
Water occupies three main fluid compartments
intracellular fluid (ICF)
extracellular fluid (ECF)
plasma (blood)
Fluid inside cells
Accounts for two-thirds of body fluid
intracellular fluid
Fluids outside cells; includes blood plasma, interstitial
fluid (IF), lymph, and transcellular fluid
extracellular fluid
is ECF, but accounts for 3L of total
body water.
Links external and internal environments
plasma (blood)
are charged particles (ions) that conduct electrical current in an aqueous solution
Electrolytes
Sodium, potassium, and calcium ions are
electrolytes
Water intake must equal ??? if the body is to remain properly hydrated
water output
Sources for water intake (2)
Ingested foods and fluids
Water produced from metabolic processes (10%)
is the driving force for water intake
Thirst mechanism
are sensitive cells in the hypothalamus that become more active in reaction to small changes in plasma solute concentration
Osmoreceptors
osmoreceptors, when activated, the ??? in the hypothalamus
is notified
thirst center
A dry mouth due to decreased saliva also promotes the
thirst mechanism
Sources of water output (4)
Lungs (insensible since we cannot sense the water
leaving)
Perspiration
Feces
Urine
are primarily responsible for reabsorption of water and electrolytes by the
kidneys
Hormones
prevents excessive water
loss in the urine and increases water reabsorption; targets the kidney’s collecting ducts
Antidiuretic hormone (ADH)
A second hormone, ???, helps regulate blood composition and blood volume by acting on
the kidney
aldosterone
For each sodium ion reabsorbed, a ??? follows, and a ??? is secreted into the filtrate
chloride ion;
potassium ion
when sodium is reabsorbed, ???
follows it passively back into the blood
water
Most important trigger for aldosterone release
Renin-angiotensin mechanism
renin-angiotensin mechanism: Mediated by the ??? of the renal tubules
juxtaglomerular (JG) apparatus
When cells of the JG apparatus are stimulated by low blood pressure, the enzyme ??? is released into blood
renin
Renin catalyzes reactions that produce ???
angiotensin II
Angiotensin II causes
vasoconstriction and aldosterone release
renin-angiotensin mechanism result
increase in blood volume and blood pressure
blood pH above 7.45
Alkalosis
blood pH below 7.35
Acidosis
Blood pH must remain between ??? to maintain homeostasis
7.35 and 7.45
blood pH between 7.0 and 7.35
Physiological acidosis
play greatest role in maintaining acid base balance
Kidneys
Other acid-base controlling systems (other than kidneys)
Blood buffers and Respiration
blood buffers
acids
bases
proton (H+) donors
acids
dissociate completely and liberate all of their H+ in water
Strong acids
???, such as ???, dissociate only partially
Weak acids;
carbonic acid
proton (H+) acceptors
bases
dissociate easily in water and tie up H+
Strong bases
???, such as ???, are slower to accept H+
Weak bases;
bicarbonate ion and ammonia
react to prevent dramatic changes in hydrogen ion (H+) concentrations
Molecules
molecules: ??? to H+ when pH drops
Bind
molecules: ??? H+ when pH rises
Release
Three major chemical buffer systems
- Bicarbonate buffer system
- Phosphate buffer system
- Protein buffer system
Mixture of carbonic acid (H2CO3) and sodium bicarbonate (NaHCO3)
The bicarbonate buffer system
a weak acid that does not dissociate much in neutral or acid solutions
Carbonic acid
react with strong acids to change them to weak acids
Bicarbonate ions (HCO3−)
dissociates in the presence of a strong base to form a weak base and water
Carbonic acid
can rise and fall depending on changing blood pH to retain CO2 (decreasing the blood pH) or remove CO2 (increasing the blood pH)
Respiratory rate
When blood pH ???:
Bicarbonate ions are excreted
Hydrogen ions are retained by kidney tubules
renal mechanisms;
rises
When blood pH ???:
Bicarbonate ions are reabsorbed
Hydrogen ions are secreted
renal mechanisms;
falls
Urine pH varies from ?? to ??
4.5 to 8.0
The kidneys begin to develop in the ?
first few weeks of embryonic life
they kidneys are excreting urine by the ??? month of fetal life
third
Common congenital abnormalities include
polycystic kidney and hypospadias
Common urinary system problems in children and young to middle-aged adults include:
- infections caused by fecal microorganisms,
- microorganisms causing sexually transmitted infections, and
- Streptococcus
Control of the voluntary urethral sphincter does not start until what age
18 months
Complete nighttime control may not occur until the child is how many years old?
4 years old
are the only common problems before old age
Urinary tract infections (UTIs)
a bacterium, accounts for 80
percent of UTIs
Escherichia coli (E. coli)
is an uncommon but serious problem in which the kidneys are unable to concentrate urine, and dialysis must be done to maintain chemical homeostasis of blood
Renal failure
With age, ??? decreases and ???become less efficient at concentrating urine,
leading to urgency, frequency, and incontinence
filtration rate;
tubule cells;
In men, ??? is another common problem
urinary retention
Problems associated with aging (5)
urgency
frequency
nocturia
incontinence
urinary retention
feeling that it is necessary to void
Urgency
frequent voiding of small amounts of urine
Frequency
need to get up during the night to urinate
Nocturia
loss of control
Incontinence
common in males, often the result
of hypertrophy of the prostate gland
Urinary retention
often the result of hypertrophy of the prostate gland
urinary retention
inflammation of the kidney
pyelonephritis
dropping of the kidney to a more inferior position in the abdomen; may result from a rapid weight loss that decreases the fatty cushion surrounding the kidney
ptosis
backup of urine into the kidney; often a result of a blockage in the urinary tract
hydronephrosis
a condition in which excessive amounts of urine are produced because of a deficiency of ADH
diabetes insipidus
toxic condition caused by renal failure
uremia
more acidic or basic urine? protein-rich diet
acidic
more acidic or basic urine? bacterial infection
basic
more acidic or basic urine? starvation
acidic
more acidic or basic urine? diabetes insipidus
basic
more acidic or basic urine? vegetarian diet
basic
would cause an increase or decrease in urine-specific gravity? drinking excessive fluids
decrease
would cause an increase or decrease in urine-specific gravity? chronic renal failure
decrease
would cause an increase or decrease in urine-specific gravity? pyelonephritis
increase
would cause an increase or decrease in urine-specific gravity? using diuretics
decrease
would cause an increase or decrease in urine-specific gravity? limited fluid intake
increase
would cause an increase or decrease in urine-specific gravity? fever
increase
more acidic or basic urine? intense exercise
acidic
