Urinary

Question 1

Urinary System Functions

Answer 1

Excretion & Elimination
Regulation of Blood Volume and Blood Pressure
Regulation of Plasma Concentrations of Ions
Helps Stabilize Blood pH
Conserves Valuable Nutrients

Question 2

Excretion and Elimination

Answer 2

Organic waste products generated by metabolism and normal cell function
Especially urea and uric acid

Question 3

Regulation of Blood Volume and Blood Pressure

Answer 3

Adjusting volume of water lost (ADH & Aldosterone)
Releasing EPO
Releasing Renin

Question 4

Regulation of Plasma Concentrations of Ions

Answer 4

Na, K, Cl (controls amount lost in urine)
Releases Calcitriol (Ca)

Question 5

Helps Stabilize Blood pH

Answer 5

Controls the loss of H+ ions and HCO3 in urine

Question 6

Conserves Valuable Nutrients

Answer 6

Glucose, amino acids

Question 7

Cortex

Answer 7

outermost portion of kidney

Question 8

Medulla

Answer 8

inner layer containing renal poyramids

Question 9

Nephrons

Answer 9

functional units of urine production and regulation of plasma concentrations and volume of solutes

Question 10

Blood leaves through

Answer 10

renal vein

Question 11

Blood enters through

Answer 11

renal artery

Question 12

Renal corpuscle

Answer 12

Composed of Bowman’s capsule and glomerulus

Site of filtration

Question 13

Proximate convoluted tubule

Answer 13

Reabsorbs water, ions and organic nutrients

Question 14

Loop of Henle

Answer 14

Descending
Water reabsorption
Ascending
Sodium and chloride reabsorption

Question 15

Distal convoluted tubule

Answer 15

Secretion of ions, acids, drugs, toxins

Selective** reabsorption of water, sodium and calcium

Question 16

Collecting duct (part of collecting system)

Answer 16

Selective** reabsorption of water

Selective** secretion or reabsorption of sodium, potassium, hydrogen and bicarb

Question 17

Papillary duct (part of collecting system)

Answer 17

Delivers urine to minor calyx for transport out

Question 18

what are nephrons surrounded by and what are they?

Answer 18

surrounded by peritubular capillaries.
The capillaries are where nutrients are returned to the blood stream (reabsorption).
The capillaries also contain the ions, acids, drugs, and toxins that are selectively secreted into filtrate.

Question 19

Reabsorption

Answer 19

from filtrate back into circulation

Question 20

Secretion

Answer 20

from circulation into filtrate

Question 21

**Selective reabsorption and secretion

Answer 21

Water etc… are reabsorbed or secreted on a variable basis.

Hormones determine the amount of materials either secreted or absorbed (DCT).

Question 22

Antidiuretic Hormone

Answer 22

Regulates water concentrations
High ADH = low urine output
impacted by alcohol
increase in blood pressure with high amount

Question 23

Aldosterone

Answer 23

Regulates salt concentrations
High Aldosterone = hold on to Na+ and lose K+
high amount increase blood pressure

Question 24

Summary of Renal Function

Answer 24

1. Filtrate is produced at renal corpuscle.
2. The PCT reabsorbs ions, organic nutrients and water.
3. The PCT and descending part of loop of Henle reabsorb water.
4. The ascending loop sodium and chloride are actively reabsorbed.
5. DCT makes final adjustments via selective secretion and reabsorption.
6. DCT and collecting duct make final volume adjustments by selectively removing water.
7. Urine is transported to the papillary duct then minor and major calyx for removal via the ureter.

Question 25

Purpose of Urine production

Answer 25

Regulate the volume and composition of blood | Removal of dissolved solutes including metabolic waste products

Question 26

Urea

Answer 26

Mainly produced during breakdown of amino acids

Question 27

Creatinine

Answer 27

Generated via breakdown of creatine phosphate in skeletal muscle

Question 28

Uric acid

Answer 28

Produced during the breakdown and recycling of RNA

Question 29

Urine

Answer 29

``` Slightly acidic Mainly water (93-97%) Sterile (no bacteria) Composition depends on filtration absorption and secretion levels of ions, wastes, nutrients etc… Major waste product is urea ```

Question 30

Ureter

Answer 30

Muscular tubes from kidneys to bladder.

Question 31

Urinary Bladder

Answer 31

Contains the trigone which acts as a funnel. | Main purpose is urine storage.

Question 32

Urethra

Answer 32

Internal urethral sphincter External urethral sphincter Males vs. Females

Question 33

Filtration

Answer 33

Occurs in the renal corpuscle Blood pressureforces water and dissolved solutes out of glomerular capillaries and into capsular space Produces a protein-free solution (filtrate) From renal corpuscle filtrate flows into renal tubule

Question 34

PCT

Answer 34

First segment of tubule Tubular cells reabsorb organic nutrients, ions, water and any plasma proteins present Secrets H+ ions, ammonia, creatinine, drugs, and toxins Secretion Reabsorption from filtrate into peritubular capillaries via…

Question 35

Loop of Henle

Answer 35

Most of the volume of filtrate (60-70%) reabsorbed prior to reaching loop Loop reabsorbs ~50% of remaining water and the majority of remaining Na+ and Cl- Reabsorption is performed via countercurrent multiplication between the ascending and descending limbs

Question 36

Countercurrent Multiplication

Answer 36

Countercurrent b/c tubular fluid in descending limb flows towards the renal pelvis and tubular fluid in the ascending limb flows toward the cortex Multiplication b/c the effect of the exchange increases as movement of the fluid continues

Question 37

Thin descending limb

Answer 37

Permeable to water | Relatively impermeable to solutes

Question 38

Thick ascending limb

Answer 38

Relatively impermeable to both water and solutes | “Pumps” to actively transport sodium and chloride from tubular fluid into peritubular fluid

Question 39

Net result

Answer 39

Greater solute concentration difference between peritubular fluid and descending limb = more water out via osmosis and Greater solute concentration into ascending limb accelerates the active transport of sodium and chloride out into peritubular fluid Urea and other organic wastes now represent a significant proportion of the dissolved solutes

Question 40

DCT

Answer 40

Tubular fluid composition and volume change dramatically from the capsular space to the distal convoluted tubule

Question 41

Selective Reabsorption (DCT)

Answer 41

Actively transport Na+ & Cl- out of tubular fluid via active transport (Na+ also via exchange pumps, usually K+) Aldosterone results in a reduction of Na+ ions lost in urine (which results in water conservation as well) Primary site of Ca2+ reabsorption regulated by levels of parathyroid hormone and calcitriol

Question 42

Secretion (DCT)

Answer 42

Can vary depending on concentrations in peritubluar capillaries and fluid. When concentrations of “undesirable substances” or other materials (see table 26-3) are too high they will be secreted from peritubular fluid into the tubular fluid at the DCT K+ ions are secreted as a result of Na+/K+ exchange pumps H+ secretion due to Na+ absorption as well which results in decreased pH in tubular fluid and increased pH of the blood Secretion is accelerated when blood pH falls as in lactic acidosis and ketoacidosis

Question 43

Collecting System

Answer 43

Na+ ions can be reabsorbs in response to aldosterone via Na+/K+ exchange pumps Bicarbonate can be reabsorbed in exchange for Cl- ions in response to changes in blood and/or body fluid pH Urea can be reabsorbed in the deepest portion of the medulla (very end of collecting system) H+ or Bicarbonate ions can be secreted due to changes in body fluid pH

Question 44

Control of Urine Volume

Answer 44

Controlled via water reabsorption Obligatory water reabsorption Facultative water reabsorption Diuretics