Urinary System Flashcards
What components make up the urinary system?
The urinary system includes the kidneys, ureters, urinary bladder, and urethra.
Where is urine formed in the body?
Urine is formed in the kidneys.
How is urine transported from the kidneys to the urinary bladder?
Urine is transported by the ureters from the kidneys to the urinary bladder.
Where is urine stored before it is excreted from the body?
Urine is stored in the urinary bladder until it is excreted.
Through which structure is urine excreted from the body?
Urine is excreted from the body via the urethra.
Where are the kidneys located within the body?
The kidneys are small fist-sized organs located within the abdominal cavity on either side of the midline between the levels of T12-L3.
How are the kidneys protected and anchored in place within the body?
The kidneys are surrounded by layers of connective tissue and adipose tissue, which serve to protect and anchor them in place.
What percentage of the resting cardiac output do the kidneys normally receive?
The kidneys normally receive 20-25% of the resting cardiac output, despite their small size (<0.5% of the body’s mass).
Where are the kidneys situated in relation to the abdominal cavity?
The kidneys are in the posterior aspect of the middle of the abdominal cavity.
Despite their small size, why are the kidneys significant in terms of blood flow?
Despite their relatively small size, about a quarter of the blood ejected by the heart ends up passing through the kidneys.
What are the histological components of each kidney?
Each kidney consists of an outer renal cortex and an inner renal medulla, which is divided into sections called pyramids, separated by columns of cortex extending into the interior of the kidney.
What is the single-entry point on the medial surface of each kidney called?
The single-entry point on the medial surface of each kidney is called the hilum or hilus.
What structures enter and exit the kidney through the hilum?
Through the hilum, the ureter, renal artery, and renal vein enter and exit the kidney.
How are the pyramids and cortex arranged within the kidney?
The pyramids are sections of the renal medulla, separated by columns of cortex extending into the interior of the kidney.
What is the functional significance of the hilum in the kidney?
The hilum serves as the entry and exit point for structures essential for kidney function, including the ureter, renal artery, and renal vein.
Renal cortex
Portions extend into the renal medulla (renal columns)
Renal medulla
Consists of several cone-shaped sections (renal pyramids)
Renal Hilum
Entry/exit point for the:
Ureter
Renal blood vessels
Nerves and lymphatic vessels
What is the functional unit of the kidney?
The functional unit of the kidney is the nephron, which consists of a renal corpuscle and renal tubule.
how many nephrons are extending through the renal cortex and renal pyramids of each kidney?
~ 1,000,000 nephrons
what is the capillary network called?
glomerulus
what is the glomerulus (capillary network) surrounded by?
glomerular (Bowman’s) capsule
what does the glomerular (Bowman’s) capsule do?
The capsule filters the blood in the glomerulus and deposits the filtered fluid (“filtrate”) into the renal tubule
What is formed when portions of blood are filtered into the glomerular capsule?
When portions of blood are filtered into the glomerular capsule, they form filtrate.
What are the three main components of the renal tubule?
The renal tubule consists of a proximal convoluted tubule, loop of Henle, and distal convoluted tubule.
What happens to the composition of filtrate as it passes through the renal tubule and distal convoluted tubules?
The composition of filtrate is adjusted, and urine is formed when neighboring nephrons dump their leftover filtrate into a collecting duct.
What happens to the renal artery after entering the kidney?
After entering the kidney, the renal artery branches into progressively smaller arteries and arterioles that spread throughout the renal tissue.
What structures enter a nephron’s glomerular capsule from afferent arterioles?
Afferent arterioles give rise to a glomerulus that enters a nephron’s glomerular capsule.
What is the function of efferent arterioles in the kidney?
Efferent arterioles exit the glomerular capsule and branch into peritubular capillaries surrounding the tubular portion of the nephron.
What happens to peritubular capillaries after surrounding the renal tubule?
Peritubular capillaries eventually reunite to form venules, which form progressively larger veins that drain into the renal vein.
What is the role of the renal vein in the kidney?
The renal vein drains blood out of the kidney, receiving blood from progressively larger venules and veins formed by peritubular capillaries.
Afferent arterioles
each gives rise to a glomerulus that enters a nephron’s glomerular capsule
Efferent arterioles
exit the glomerular capsule and branch into peritubular capillaries that surround the tubular portion of the nephron
What is glomerular filtration?
Glomerular filtration is the movement of water and solutes from the glomerular capillary into the glomerular capsule.