E4 - The Urinary System [CHAPTER QUESTIONS]

Question 1

What functions does the kidneys perform to maintain homeostasis:

Answer 1

(1) maintain water balance in the body; (2) maintain the proper osmolarity of body fluids, primarily by regulating water balance; (3) regulate the quantity and concentration of most ECF ions; (4) maintain proper plasma volume by adjusting NaCl and water balance; (5) participate in maintaining acid-base balance by adjusting H+ and HCO3 - output in the urine; (6 excrete metabolic wastes such as urea, uric acid, creatinine, bilirubin, and hormone metabolites in the urine; (7) excrete foreign compounds such as drugs, food additives, pesticides, and other non-nutritive materials that enter the body; (8) produce erythropoietin; (9) produce renin, an enzyme important in salt conservation; and (10) convert vitamin D precursor to the active molecule.

Question 2

What organs make up the urinary system?

Answer 2

The kidneys, ureters, urinary bladder, and urethra make up the ______ system.

Question 3

The kidneys are supplied by the _____ artery and the _____ vein.

Answer 3

The renal artery and vein supply the _____.

Question 4

Where is urine collected and stored?

Answer 4

Urine is collected
into the renal pelvis and channeled into the ureters, which carry urine to the urinary bladder where the urine is stored then emptied through the urethra outside the body.

Question 5

What are nephrons?

Answer 5

The functional unit of the kidney _____ which arrangement gives rise renal cortex and renal medulla. Also the they consists of the vascular and tubular components which makes up the Juxtaglomerular apparatus.

Question 6

What makes up the vascular components of nephrons?

Answer 6

The afferent arteriole, glomerulus, efferent arteriole,

and peritubular capillaries make up the _____ components nephrons.

Question 7

What makes up the tubular components of nephrons?

Answer 7

The Bowman’s capsule, proximal tubule, loop of

Henle, distal tubules, and collecting ducts make up the _____ components of nephrons.

Question 8

What makes up the Juxtaglomerular apparatus?

Answer 8

The combination of vascular and tubular components make up the ______________.

Question 9

What are the two types of nephrons?

Answer 9

Cortical (80%) and Juxtamedullary (20%) nephrons.

Question 10

Where are the glomeruli of the cortical and Juxtamedullary nephrons located in the kidney?

Answer 10

The glomeruli of the cortical nephrons lie in the outer region of the cortex; the glomeruli of the juxtamedullary nephrons lie in the inner layer of the cortex.

Question 11

The hairpin loop of the cortical and Juxtamedullary nephrons venture into what region of the kidney?

Answer 11

The hairpin loop of cortical nephrons dips
only slightly into the medullary region, while the loop of the juxtamedullary nephrons projects deeply
into the medulla.

Question 12

What are the 3 renal processes for the formation of urine?

Answer 12

Glomerular filtration, tubular reabsorption, and tubular secretion are the processes for ________.

Question 13

Is the glomerular membrane permeable?

Answer 13

The Glomerular membrane is 100 times more permeable to water and solutes than the capillaries in the body.

Question 14

What 3 layers make up the glomerular membrane?

Answer 14

The glomerular capillary wall, basement membrane, inner layer of Bowman’s (capsule composed of podocytes ) make up the _______ membrane.

Question 15

How much of the plasma that enters the glomerulus is removed as filtrate?

Answer 15

About 20% of the plasma is removed from the _____ as filtrate.

Question 16

How much glomerular filtrate is produced per day?

Answer 16

The 2.75 L of plasma is filtrated 65 times per day to produce 180 L of glomerular filtrate per day.

Question 17

What forces induce and opposes glomerular filtration?

Answer 17

Glomerular capillary blood pressure (55 mm Hg) is the major force that induces glomerular filtration.
Plasma-colloid osmotic pressure (30 mm Hg) and Bowman’s capsule hydrostatic pressure (15 mm Hg)opposes glomerular filtration. Therefore, the net filtration pressure is 10 mm Hg favoring glomerular filtration (Review table 14-1, pg. 513)

Question 18

What are some factors that effect the glomerular filtration rate (GFR)?

Answer 18

Glomerular filtration rate (GFR) depends on the net filtration pressure, the surface area of the
glomerular membrane available for filtration, and how permeable (Kf) the glomerular membrane is.

Therefore, GFR = Kf x net filtration pressure

Question 19

What forces can invoke changes in the glomerular filtration rate (GFR)?

Answer 19

Changes in the GFR primarily result from changes in glomerular capillary blood pressure which are caused primarily by changes in the volume of blood flowing into the glomerulus.

Plasma colloid osmotic pressure and Bowman’s capsule hydrostatic pressure are not subject to control and only change pathologically..

Question 20

What are mechanisms

for changing glomerular capillary blood pressure are….

Answer 20

(1) autoregulation, or (2) extrinsic sympathetic

control of arterial blood pressure.

Question 21

What two intrarenal mechanisms are involved in autoregulation of glomerular capillary blood pressure?

Answer 21

A myogenic mechanism and the tubuloglomerular feedback (TGF) combined make up the __________ of the glomerular capillary blood pressure.

Question 22

What can override autoregulation of the glomerular capillary blood pressure?

Answer 22

The sympathetic nervous system can override autoregulation (extrinsic control). This response will be coordinated by the
cardiovascular control center located in the brainstem, through increased sympathetic activity to the heart and blood vessels.

Question 23

What influence changes in the filtration coefficient?

Answer 23

The GFR can be influenced by changes in the filtration coefficient. The glomerular capillary tufts are held together by mesangial cells, which contain contractile elements. Contraction of these cells results in
reduce filtration surface area, thus a reduction in Kf. Podocytes also possess contractile elements and can
increase or decrease Kf by changing the size of the filtration slits (see figure 14-13, pg 518).

Question 24

What substances are filtered through the glomerular capillaries?

Answer 24

All plasma constituents except plasma proteins are indiscriminately filtered through the glomerular
capillaries. This includes wastes and desirable materials such as nutrients, electrolytes, and other
substances too important to lose in the urine. These essential materials are brought back into the plasma by tubular reabsorption.

Question 25

What are the five layers substances must go through during transepithelial transport?

Answer 25

(1) luminal membrane of the tubular cell, (2) cytosol of the tubular cell, and (3) basolateral membrane of
the tubular cell, to reach the: (4) interstitial fluid, and (5) capillary wall, to enter blood plasma

Question 26

Is tubular reabsoption passive or active?

Answer 26

______________ can be passive or active. In passive tubular reabsorption, all five steps are passive. In active tubular reabsorption, energy is required and substances can be transported against their electrochemical gradient.

Question 27

Is an active Na+-K+ ATPase pump in the basolateral membrane essential for Na+ reabsorption?

Answer 27

An active Na+-K+ ATPase pump is essential for Na+ reabsorption.

Eighty percent of the total energy used by the kidneys is for Na+ transport. Of the Na+ reabsorbed, 67 percent
occurs in the proximal tubule, 25 percent in the loop of Henle, and 8 percent in the distal and collecting tubules is under hormonal control.

Question 28

Does the reabsorption of other substances depends on Na+ reabsorption? If so, where is the Na+ essential for other sudstances?

Answer 28

Yes the reabsorption of other substances depends on Na+ reabsorption during tubular reabsorption. (1) Na+ reabsorption in the proximal tubule is important for the passive reabsorption of glucose, amino acids, H2O, Cl-, and urea. (2) Na+ reabsorption in the ascending limb of the loop of Henle, along with Cl- reabsorption, plays a critical role in the kidneys being able to produce urine of varying concentrations and volumes. (3) Na+ reabsorption in the distal and collecting tubules is important in regulating ECF volume, blood pressure, and K+ secretion.