Chapter 11: The Urinary System Flashcards
What’s the primary function of the urinary system?
Regulate extracellular fluids of the body (plasma and tissue fluid).
Define electrolyte:
Mineral salt of the body that carries an electrical charge and regulates nerve impulses, muscle contractions, hydration, and blood pH.
Define filtrate:
Fluid that passes from the blood through the capillary walls of the glomeruli to the Bowman capsule. Urine is formed from filtrate, which is similar to plasma with less protein.
Define nitrogenous waste:
Product of protein metabolism that includes urea, uric acid, creatine, creatinine, and ammonia.
Define peristaltic wave:
Sequence of rhythmic contractions of smooth muscles of a hollow organ to force material forward and prevent backflow.
Define peritoneum:
Serous membrane that lines the abdominopelvic cavity and covers most of the organs within the cavity.
Define pH:
Symbol that expresses the acidity or alkalinity of a solution. [acidic < 7 (neutral) < alkaline]
Define plasma:
Liquid portion of blood filtered by nephrons to remove dissolved waste.
What happens if the kidneys do not continuously remove wastes?
Death
What is erythropoietin?
Produced by the kidneys that stimulates RBC production in bone marrow when O2 levels are low.
Tell me about the kidneys:
Each are about the size of a fist, bean-shaped, and are retroperitoneal. In a cross-section view, they have an outer renal cortex and inner renal medulla.
Renal cortex
Outer layer of the kidneys (in a cross-section view)
Renal medulla
Inner layer of the kidneys (in a cross section view)
Nephrons
Microscopic filtering units of the kidneys.
Hilum (singular hilus)
An opening near the medial border of the kidneys through which the renal artery enters and the renal vein exits.
Renal pelvis
Hollow cavity where the ureter merges with the kidney.
Tell me about the ureters:
Each is ~10”-12” long; these carry urine in peristaltic waves to the bladder.
What is the urethral orfice?
Where the ureters meet the urinary bladder.
Tell me about the urinary bladder:
It’s an expandable, hollow organ that acts as a temporary reservoir for urine. It has small folds called rugae that expand as the bladder fills.
What’s the trigone?
Triangular area at the base of the bladder formed by the openings of the ureters and urethra; leads into the urethra.
Tell me about the urethra:
Tube that discharges urine from the bladder. ~1.5” in women and ~7-8” in men. In males, the urethra passes through the prostate gland and the penis.
What’s micturition?
urination
What’s the urinary meatus?
Opening in the urethra through which urine is excreted from the body.
About how many nephrons are there in a kidney?
1 million
Function of a nephron:
Maintain homeostasis by continually adjusting the volume, composition, and pH of blood plasma and tissue fluid. Each nephron contains a renal corpuscle and a renal tubule.
What’s a renal corpuscle?
Composed of tuft capillaries called the glomerulus that is surrounded by the Bowman capsule.
What is a renal tubule?
Connected to the renal corpuscle and consists of 4 structures:
1) Proximal convoluted tubule
2) Loop of Henle
3) Distal convoluted tubule
4) Collecting tubule
What does the collecting tubule do?
Transports newly formed urine to the renal pelvis for excretion from the kidneys.
What is the afferent arteriole?
Carries blood to the glomerulus.
What is the efferent arteriole?
Carries blood from the glomerulus. This passes behind the renal corpuscle to form the peritubular capillaries (capillaries that surround the renal tubule).
What are the 3 physiological functions of the nephron?
Filtration, reabsorption, and secretion.
What is filtration?
Occurs in the renal corpuscle as water, sugar, electrolytes, and other small particles in plasma in the afferent arteriole pass into the Bowman capsule to form filtrate.
What is reabsorption?
Begins as filtrate travels along the long, twisted path of the tubule. Most of the water, and some electrolytes and amino acids, from the tubule re-center the circulating blood through the peritubular capillaries.
What is secretion?
Final stage of urine formation; peritubular capillaries actively secrete waste products into the renal tubules for removal in urine. Urine then moves to the renal pelvis, to the bladder for temporary storage, then exits the body.
albumin/o
albumin; protein
azot/o
nitrogenous compounds
bacteri/o
Bacteria
cyst/o
vesic/o
bladder
glomerul/o
glomerulus
kal/i
potassium
kal/i/ur/esis: condition of potassium in the urine.
keton/o
ketone bodies (acids and acetones)
lith/o
stone; calculus
meat/o
meatus; opening
nephr/o
ren/o
kidney
noct/o
night
olig/o
scanty
py/o
pus
pyel/o
renal pelvis
ur/o
urine; urinary tract
ureter/o
ureter