The Urinary System: Kidney & Nephron

Question 1

The 2 kidneys of the urinary system

Answer 1

Filter blood & produce urine

Question 2

The 2 ureters of the urinary system

Answer 2

Transport urine from the kidneys to the urinary bladder

Question 3

The urinary bladder is

Answer 3

A temporary storage reservoir for urine

Question 4

The urethra

Answer 4

Transports urine out of the body

Question 5

The functions of the kidneys are

Answer 5

Excretion of nitrogenous waste (urea, ammonia, creating, uric acid, and urobilin), drugs & environmental toxins

Regulation of blood ion, pH & osmolarity

Regulation of blood volume & pressure

Hormone production (e.g., erythropoietin)

Regulation of blood glucose (gluconeogenesis)

Question 6

The kidneys lie

Answer 6

Retroperitoneal in the superior lumbar region
◦Right kidney is lower than left (crowded by liver)

Question 7

The 3 layers of supportive tissue surrounding the kidneys are

Answer 7

◦Renal fascia – outer layer of dense fibrous
connective tissue that anchors kidney & adrenal gland to surrounding structures
◦Perirenal fat capsule – surrounds & cushions the
kidney
◦Fibrous capsule – transparent capsule that
protects from surrounding infections & trauma

Question 8

The renal hilum is

Answer 8

An indentation along concave border of the kidney
◦ Ureter, blood vessels, lymphatic vessels, nerves

Question 9

Outermost region of the kidney is

Answer 9

The renal cortex

Question 10

Middle region of the kidney is

Answer 10

The renal medulla (contains renal pyramids)

Question 11

Innermost region of the kidney is

Answer 11

The renal pelvis, a funnel-shaped tube continuous with the ureter
◦ Minor & major calyces collect urine & empty it
into the renal pelvis

Question 12

Blood enters each kidney through one renal artery via

Answer 12

Arterial blood flow

Question 13

Blood flows into the renal cortex through

Answer 13

Progressively smaller arteries

Question 14

Gives rise to microscopic vasculature that is a key element of kidney function

Answer 14

Afferent arterioles

Question 15

Blood leaves the kidneys via the

Answer 15

Veins (renal arterial circulation in reverse)

Question 16

The renal nerve plexus composed mostly of sympathetic fibres regulates renal blood flow by

Answer 16

Adjusting the diameter of renal arterioles & influencing the formation of urine by the nephron

Question 17

The structural & functional units that form urine are

Answer 17

Nephrons (1 million+ per kidney)

Question 18

Nephrons form a

Answer 18

Cell- & protein-free filtrate from blood that
◦ Recovers (reabsorbs) chemicals the body needs
◦Secretes selected chemicals to get rid of

Question 19

Two main parts of a nephron are:

Answer 19

Renal corpuscle (filters plasma)
◦ Located in renal cortex
Renal tubules (regulates filtrate via selective absorption & secretion)
◦ Starts in renal cortex, passes into medulla, &
returns to cortex

Question 20

The glomerulus of the renal corpuscle is composed of

Answer 20

Fenestrated capillaries that increase permeability to form a solute-rich, but protein-free, filtrate

Question 21

The glomerular (Bowman’s) capsule of the renal corpuscle is

Answer 21

A Double-walled epithelial cup surrounding the glomerulus
◦Parietal layer – contributes to capsular structure
◦Visceral layer – associated with the glomerular capillaries (consists of podocytes)

Question 22

The path of filtrate in the renal tubule of the kidneys is:

Answer 22

Proximal convoluted tubule (PCT)

Nephron loop (loop of Henle)
- descending then ascending limb

Distal convoluted tubule (DCT)

Collecting duct

Question 23

The epithelium of the renal tubule & collecting duct is

Answer 23

Simple (1 layer)

Question 24

The epithelium of the PCT has

Answer 24

Dense microvilli to ↑SA for absorption & secretion

Question 25

The epithelium of the nephron loop is

Answer 25

◦ simple squamous in the thin descending limb ◦ both thin and thick (simple cuboidal) in the ascending limb

Question 26

The cells of the DCT epithelium lack

Answer 26

Microvilli

Question 27

Principal cells in the collecting ducts control

Answer 27

H2O & Na+ balance via Na+ channels & aquaporins

Question 28

The intercalated cells in the collecting ducts control

Answer 28

pH by secreting/absorbing H+ or HCO3-

Question 29

The collecting ducts collect filtrate from many nephrons & extend through the renal pyramid to the

Answer 29

Renal papilla, where they empty into a minor calyx ◦ Give the pyramids their striped appearance

Question 30

The 2 classes of nephron are

Answer 30

Cortical and Juxtamedullary

Question 31

Nephrons that are ◦ the majority (85%) ◦ located almost entirely within cortex ◦ have a short nephron loop

Answer 31

Cortical nephrons

Question 32

Nephrons that are ◦ Located near the cortex-medulla junction ◦ Have a long nephron loop ◦ play an important role in kidney’s ability to concentrate urine (help with water conservation)

Answer 32

Juxtamedullary nephrons

Question 33

The nephron capillary beds formed by the efferent arteriole are

Answer 33

Peritubular capillaries surrounding the cortical tubule ◦ Low-pressure, porous, absorb solutes & H2O from tubule cells Vasa recta surrounding the medulla tubule ◦ Arise from the efferent arterioles near juxtamedullary nephrons & run parallel to longest nephron loops (counter current)

Question 34

Being fed & drained by afferent & efferent arterioles maintains the

Answer 34

The high pressure in the glomerulus that is necessary for filtration

Question 35

The juxtaglomerular complex if the region where

Answer 35

The afferent arteriole & distal convoluted tubule (DCT) meet ◦ Regulates rate of filtrate formation & systemic blood pressure

Question 36

The macula densa cells (chemoreceptors) in the DCT monitor

Answer 36

The NaCl content of filtrate entering DCT

Question 37

The juxtaglomerular cells in walls of the afferent arterioles act like mechanoreceptors to monitor

Answer 37

Blood pressure & house secretory vesicles containing the enzyme renin