STRUCTURAL AND FUNCTIONAL ORGANIZATION OF THE URINARY SYSTEM Flashcards
What consists of two kidneys, two ureters, one urinary bladder, and one urethra?
The urinary system
After the kidneys filter the blood, they return most of the water and many solutes to the bloodstream, what does the remaining water and solute constitute?
Urine
What is the scientific study of anatomy, physiology, and disorders of the kidneys?
Nephrology
What is the branch of medicine that deals with the male and female urinary system, and the male reproductive system?
Urology
What are these functions of?
- Regulation of ion levels in the blood
- Regulation of blood volume and blood pressure
- Regulation of blood pH
- Production of hormones
- Excretion of wastes
Functions of the kidneys
The kidneys help regulate blood levels of several ions, most importantly what?
- Sodium ion (Na+)
- Potassium ions (K+)
- Calcium ions (Ca2+)
- Chloride ions (Cl-)
- Phosphate ions (HPO)
True or False
The kidneys adjust the volume of blood in the body by returning water to the blood or eliminating it in the urine
True
The kidneys help regulate blood pressure by secreting what enzyme?
Renin
The enzyme renin activates what pathway, by adjusting blood flow into and out of the kidneys, and by adjusting blood volume?
Renin-angiotensin-aldosterone pathway
How do the kidneys regulate blood pH?
Regulating the concentration of H+ in the blood and conservation of the blood bicarbonate ions (HCO3-), an important buffer of H+
What two hormones do the kidneys produce?
- Calcitrol
a. active form of vitamin D, regulates calcium homeostasis - Erythropoietin
a. stimulates RBC production
What are some wastes excreted in the urine?
- Ammonia and urea (breakdown of amino acids)
- Bilirubin (breakdown of hemoglobin)
- Creatinine (breakdown of creatine phosphate in muscle fibers)
- Uric acid (breakdown of nucleic acids)
- Drugs and environmental toxins
What organs lie at the level of the 12th thoracic and first three lumbar vertebrae?
Kidneys
True or False
The right kidney is slightly lower than the left because the liver occupies a large area above the kidney on the right side
True
What is the indentation alone the medial border of the kidney through which the ureter leaves the kidney and blood vessels, lymphatic vessels, and nerves enter and exit?
Renal Hilum
What surrounds each kidney, is a smooth connective tissue sheath that helps maintain the shape of the kidney and serves as a barrier against trauma?
Transparent renal capsule
What surrounds the renal capsule and serves as a cushion for the kidney, and anchors the kidney to the posterior abdominal wall?
Adipose (fatty) tissue
What are the two main internal regions of the kidneys?
- Renal cortex, outer light-red region
2. Renal medulla, inner, darker red-brown region
Within the renal medulla are several cone-shaped renal pyramids; extensions of the renal cortex, called _____, fill the spaces between renal pyramids.
Renal columns
Urine formed in the kidney passes from thousands of papillary ducts within the renal pyramids into cuplike structures called minor calyces; each kidney has how many minor calyces?
8-12
After leaving the minor calyces, urine next flows into how many major calyces, and then into the urinary bladder for storage and elimination from the body?
2-3 major calyces
Collecting ducts –>papillary ducts (in pyramids) –>minor calyces –>major calyces –> renal pelvis –>ureter–> where ?
urinary bladder –> urethra –>external
About how much of the resting cardiac output flows into the kidneys through the right and left renal arteries?
20-25% (1200mL a minute)
Within each kidney, the renal artery divides into smaller and smaller vessels (segmental, interlobar, arcuate, interlobular arteries) that eventually deliver blood to what?
Afferent arterioles
What does each afferent arteriole divide into?
Glomerulus
The capillaries of the glomerulus reunite to for what kind of arteriole?
Efferent arteriole
After leaving the glomerulus, each efferent arteriole divides to form a network of capillaries around the what?
Kidney tubules
True or False
Peritubular capillaries eventually reunite to form peritubular veins, which merge into interlobular, arcuate, and interlobar veins
True
What is the functional unit of the kidney?
Nephron
About how many nephrons are in each kidney?
1 million
What are the two parts of a nephron?
- Renal corpuscle
a. blood plasma is filtered here - Renal tubule
a. where glomerular filtrate passes
What are the two parts that make up a renal corpuscle?
- Glomerulus
2. Glomerular (Bowman’s) capsule
What is a double-walled cup of epithelial cells that surrounds the glomerular capillaries?
Bowman’s capsule
Glomerular filtrate first enters the glomerular capsule and then passes into the what?
Renal tubule
What are the three main sections of the renal tubule and in what order does fluid pass through them?
- Proximal convoluted tubule
- Loop of Henle
- Distal Convoluted tubule
The renal corpuscle and both convoluted tubules lie within the what? The loop of Henle extends into where?
- Renal cortex
2. Renal medulla
True or False
The distal convoluted tubules of several nephrons empty into a common collecting duct and several collecting ducts merge to form a papillary duct, which leads to a minor calyx and a major calyx, renal pelvis and ureter
True
To produce urine, nephrons and collecting ducts perform three basic processes which include what?
- Glomerular filtration
- Tubular reabsorption
- Tubular secretion
What is the first step in urine production?
Glomerular filtration
What occurs as filtered fluid flows along the renal tubule and through the collecting duct?
Tubular reabsorption
Tubule and Duct cells return about how much of the filtered water and many useful solutes to the blood flowing through the peritubular capillaries?
99%
What also takes place as fluid flows along the tubule and through the collecting duct?
Tubular secretion
By the time the filtered fluid has undergone tubular reabsorption and tubular secretion and enters the minor and major calyx it is called what?
Urine
True or False
As nephrons perform their functions, they help maintain homeostasis of the blood’s volume and composition
True
The space between the renal corpuscle and the glomerular capsule is what?
Capsular space
What cells make up the inner wall of the glomerular capsule and adhere closely to the endothelial cells of the glomerulus?
Podocytes
Together, Podocytes and glomerular endothelium form a what that permits passage of water and solutes from the blood into the capsular space?
filtration membrane
What is the pressure that causes filtration in the glomerular capillaries?
Glomerular capillary blood pressure
What are the two other pressure that oppose glomerular filtration?
- Blood colloid osmotic pressure
2. Glomerular capsule pressure
What happens when either blood colloid osmotic pressure or glomerular capsule pressure increases?
glomerular filtration decreases
Net Filtration Pressure
Normally blood pressure is greater than the two opposing pressures producing a net filtration pressure of what?
10mmHg
Net filtration pressure forces a large volume of fluid into the capsular space, about how much in males a day and how much in females a day?
- Males: 180 liters
2. Females: 150 liters
How do you get Net Filtration Pressure?
Net Filtration Pressure = glomerular capillary blood pressure – (blood colloidal osmotic pressure + glomerular capsule pressure)
True or False
When the blood pressure increases slightly or decreases slightly, changes in the diameters of the afferent and efferent arterioles can actually keep net filtration pressure steady to maintain normal glomerular filtration
True
True or False
Constriction of the afferent arteriole decreases blood flow into the glomerulus, which decreases net filtration pressure
True
True or False
Constriction of the efferent arteriole slows outflow of blood and increases net filtration pressure
True
What is the amount of filtrate that forms in both kidneys every minute called?
Glomerular Filtration Rate (GFR)
What is the normal GFR for Males?
125mL/min
What is the normal GFR for Females?
105mL/min
What happens if the bodies GFR is to high?
needed substances are unable to be reabsorbed by the body
What happens if the bodies GFR is to low?
waste products are not properly excreted
What is a hormone that promotes loss of sodium ions and water in the urine in part because it increases GFR?
Atrial Natriuretic Peptide (ANP)
Cell in what organ secrete more ANP in response to it being stretched, that occurs when blood volume increases?
Heart
With greater sympathetic stimulation (exercise, hemorrhage, etc.) the afferent arterioles are constricted more then the efferent arterioles, resulting in blood flow in the glomerular capillaries being greatyl reduced, net filtration dropping, and what else?
GFR decreasing
What is the second basic function of the nephrons and collecting ducts?
Tubular reabsorption
Returning most of the filtered water and many of the filtered solutes to the blood
Typically 99% of the filtered water is reabsorbed and only 1% of the water in glomerular filtrate actually leaves the body in urine, the fluid then drains into the what?
Renal Pelvis
What along the renal tubules and collecting ducts carry out tubular reabsorption?
Epithelial cells
What cells make the largest contribution to reabsorption?
Proximal convoluted tubule cells
True or False
The movement of solutes into the peritubular capillaries decreases the solute concentration of the tubular fluid but increases the solute concentration in the peritubular capillaries
True
What cells fine-tune reabsorption to maintain homeostatic balances of water and selected ions?
cells located distal to the proximal tubule.
Tubular secretions help eliminate what substances from the body?
- Hydrogen ions (H+)
- Potassium (K+)
- Ammonia (NH3)
- Urea
- Creatine
- Certain drugs
What is a poisonous waste that is produced when amino groups are removed from amino acids?
Ammonia