Chap 18: Urinary System Flashcards
Major excretory system of the body
URINARY SYSTEM
- a cavity where the hilum opens
Renal Sinus
bean shaped organ
kidney
organs of the urinary system
- kidney
- ureter
- urinary bladder
- urethra
layer of connective tissue that
surround each kidney
Renal Capsule
tips of the pyramids; pointing
toward the renal sinus
Renal Papillae
The kidneys are organized into 2 major regions
○ outer cortex
○ Inner medulla
where renal artery and nerves enter,
and where the renal vein, ureter, and lymphatic
vessels exit the kidney
Hilum
location for the blood-filtering structure of
the kidney
Cortex
contains the renal pyramids
Medulla
collection of tubes and ducts that
transport fluid throughout the kidney and modify it
into urine
Renal Pyramids
collects the urine for movement to
the urinary bladder
Renal Sinus
funnel-shaped chamber; surrounds the tip
of the papilla; where urine leaving the renal papilla
empties into
Calyx
transports urine from the renal pelvis to the
urinary bladder
Ureter
single, enlarged, funnel-shaped
chamber where urine from several calyces is
emptied into
Renal Pelvis
Histological and functional units of the kidney
NEPHRONS
NEPHRONS Consists of specialized structure including small tubes called
tubules
Have long loops of Henle which extend deep
into the medulla
Juxtamedullary Nephrons
have renal corpuscles
that are found deep in the cortex near the medulla
Juxtamedullary Nephrons
4 regions of a nephron:
○ Renal Corpuscle
○ Proximal Convoluted Tubule
○ Loop of Henle
○ Distal Convoluted Tubule
Where blood plasma is filtered
RENAL CORPUSCLE
Have shorter loops of Henle than
juxtamedullary, and are closer the the outer
edge of the cortex
Cortical Nephrons
have renal corpuscles that are
distributed throughout the cortex
Cortical Nephrons
Filtration portion of the nephron
RENAL CORPUSCLE
inner layer - constructed of
specialized cells called
podocytes
Consists of the glomerulus and the Bowman
capsule
RENAL CORPUSCLE
network of capillaries twisted
around each other like a ball of yarn
Glomerulus
- indented, double-walled
chamber surrounding the glomerulus
Bowman Capsule
consists of capillary
endothelium, basement membrane, and podocytes
of the Bowman capsule
filtration membrane
important regulatory
structure located next to the glomerulus
Juxtaglomerular Apparatus
Flow of filtrate through Nephron
○ Renal corpuscle
○ Proximal tubule
○ descending loop of Henle
○ ascending loop of Henle
○ Distal tubule
○ Collecting ducts
○ Papillary duct
plays an important
role in the regulation of filtrate formation and blood
pressure
renin
Blood pressure in the glomerular capillaries forces fluid and small molecules out of the blood to create filtrate
Filtration
Nonspecific process whereby materials are
separated based on size or charge
FILTRATION
3 forces or pressure determine the amount of filtrate
formed
FILTRATION PRESSURE
active transport of solutes across the nephron walls into the filtrate
Tubular Secretion
movement of substances from the filtrate across the wall of the nephron back into the blood of the peritubular capilliaries
Tubular Reabsorption
main driving force that filters substance
blood pressure
blood
pressure inside the glomerular capillaries;
outward pressure from blood pressing on
fenestrated capillary walls
Glomerular Capillary Pressure
inward pressure that
opposes filtration; due to the pressure from the
filtrate fluid in the capsular space
Capsular Pressure
inward pressure
that opposes filtration; due to the osmotic
pressure of palms proteins in the glomerular
capillaries
Colloid osmotic Pressure
Transport of water and solutes from the filtrate into
the blood
TUBULAR REABSORPTION
primary site of reabsorption
proximal convulated tubule
fluids in separate structures flow in opposite directions relative to each other. As they pass by each other, materials can be exchanged between them
countercurrent mechanism
The countercurrent mechanism creates a very high solute concentration in the medulla compared to the cortex
medullary concentration gradient
Movement of non filtered substances from the blood
into the filtrate
TUBULAR SECRETION
ammonia secretion is
passive
3 major hormonal mechanisms involved in
regulating urine concentration and volume:
○ Renin-angiotensin-aldosterone mechanism
○ Antidiuretic hormone (ADH) mechanism
○ Atrial Natriuretic Hormone (ANH) mechanism
● Initiated under low blood pressure condition
● When BP decreases, juxtaglomerular apparatuses in
the kidneys secrete renin
RENIN-ANGIOTENSIN-ALDOSTERONE MECHANISM
is secreted by neurons
in the posterior pituitary when the solute
concentration of blood increases
ANTIDIURETIC HORMONE MECHANISM
is secreted from cardiac muscle cells in the
right atrium when BP in the right atrium increases
above norma
ATRIAL NATRIURETIC HORMONE
small tubes that carry urine from the renal
pelvis of the kidney to the posterior inferior portion
of the urinary bladder
Ureters
hollow, muscular container that
lies in the pelvic cavity just posterior to the pubic
symphysis
○ Stores urine
Urinary Bladder
tube that carries urine from the urinary
bladder to the outside of the body
Urethra
triangle-shaped portion of the urinary
bladder located between the opening of the urethra
and urethra
Trigone
contracts to keep the semen from entering the bladded during the intercourse
internal urethral sphincter
consists of all
the fluid inside the cells of the body
Intracellular Fluid Compartment
consists of fluid
outside all the cells of the body
Extracellular Fluid Compartment
Water intake is controlled by neurons in
hypothalamus
helps in Ca2+
absorption
Vitamin D
Decreased Ca2+ concentrations makes cell
membranes more permeable to Na+, thus
making them more electrically excitable
Calcium Ions
lowers extracellular
Ca2+ levels
Calcitonin
Dehydration causes extracellular K+
concentrations to increases
Potassium Ions
About 90-95% of the osmotic pressure of the
extracellular fluid results from Na+
Sodium Ions:
These are reabsorbed by the active transport in
the kidneys
Phosphate and Sulfate Ions
stimulates osteoclasts of
reabsorb bone which increases
Ca2+ and phosphate;
Parathyroid hormone (PTH
is activated by stretching of
the urinary bladder wall.
MICTURITION
