Renal System

Question 1

Countercurrent Exchange System

Answer 1

Formed by the vasa recta and provide blood supply to the medulla
Does NOT remove NaCl from medulla

Question 2

Countercurrent Exchange System: Descending Capillaries

Answer 2

Water diffuses OUT of blood

NaCl diffuses INTO the blood

Question 3

Countercurrent Exchange System: Ascending Capillaries

Answer 3

Water diffuses INTO the blood

NaCl diffuses OUT of the blood

Question 4

Production of Concentrated/Dilute Urine

Answer 4

Kidneys regulate water loss in urine

ADH controls whether dilute or concentrated urine is formed

Question 5

Dilute Urine

Answer 5

Filtrate and blood have equal osmolarity in PCT
Water is reabsorbed in the thin limb, but ions reabsorbed in the thick limb of the loop of Henle create a dilute filtrate

Question 6

Concentrated Urine

Answer 6

Principal cells and ADH able to remove water from urine
Long loop makes that possible
Na/K/Cl symporters reabsorb Na and Cl from tubular fluid

Question 7

H20 Reabsorption

Answer 7

PCT: 65%
Loop: 25%
DCT: Variable controlled by hormones
Dilute urine: decreases water removes, although sufficient ions have been absorbed

Question 8

Aldosterone

Answer 8

Target: distal tubule, collecting duct
Effects: promotes Na+ and K+ secretion and reduces urine volume

Question 9

Angiotensin II

Answer 9

Target: afferent and efferent arterioles
Effects: constricts arterioles, reduces GFR, stimulates ADH and aldosterone secretion, promotes water intake and reduces urine volume

Question 10

Antidiuretic Hormone

Answer 10

Target: collecting duct
Effects: promotes H20 reabsorption, reduces urine volume, increases concentration

Question 11

Atrial Natriuretic Peptide

Answer 11

Target: afferent and efferent arterioles, collecting duct
Effects: dilates afferent arteriole, constricts efferent arteriole, increases GFR, inhibits secretion of renin, ADH, and aldosterone, inhibits NaCl reabsorption by collecting duct, increases urine volume

Question 12

Epinephrine and Norepinephrine

Answer 12

Target: juxtaglomerular apparatus, afferent arteriole
Effects: induces renin secretion, constricts afferent arteriole, reduces GFR and glomerular fluid

Question 13

Parathyroid Hormone

Answer 13

Target: proximal and distal tubules, nephron loop
Effects: promotes Ca+ reabsorption by loop and distal tubule and Mg+ reabsorption by proximal tubule, inhibits phosphate reabsorption by proximal tubule, promotes calcitrol synthesis

Question 14

Diuretics

Answer 14

Substances that slow renal reabsorption of water and causes diuresis (increased urine flow rate)
Used for treatment of congestive heart failure and hypertension

Question 15

With hyperglycemia and glycosuria…

Answer 15

Diabetes mellitus I and II

Gestational diabetes

Question 16

With glycosuria but no hyperglycemia…

Answer 16

Renal diabetes

Question 17

With no hyperglycemia or glycosuria…

Answer 17

Diabetes, ADH hyposecretion

Question 18

Urinalysis

Answer 18

Analysis of the volume and properties of urine
Normal urine is protein-free but includes filtered and secreted electrolytes (urea, creatinine, uric acid, urobilinogen, fatty acids, enzymes, and hormones)

Question 19

Blood Tests

Answer 19

Blood urea nitrogen (BUN) test measures urea in the blood

Question 20

Plasma Creatinine

Answer 20

Skeletal muscle breakdown

Question 21

Dialysis Therapy

Answer 21

Kidney function is so impaired the blood must be cleansed artificially
Separation of large solutes from smaller ones by a selectively permeable membrane

Question 22

Histology of Ureters

Answer 22

Mucosa, Muscularis, Adventitia

Question 23

Mucosa

Answer 23

Transitional epithelium and lamina propria
Has elastic properties, since organ must inflate and deflate
Mucus prevents cells from being contacted by urine

Question 24

Muscularis

Answer 24

Inner longitudinal and outer circular smooth muscle layer

Peristalsis contributes to urine flow

Question 25

Adventitia Layer

Answer 25

Loose connective tissue anchors in place | Contains lymphatics and blood vessels to supply ureter

Question 26

Location of Urinary Bladder

Answer 26

Posterior to pubic symphysis

Question 27

Anatomy of Urinary Bladder

Answer 27

Hollow, distensible muscular organ with the capacity of 700-800mL in females and 1200mL in men 2 ureteral openings and 1 urethral opening

Question 28

Which loop is permeable to water?

Answer 28

Descending loop

Question 29

Where is urine concentrated?

Answer 29

Collecting duct

Question 30

What hormone increases the permeability of the collecting duct?

Answer 30

ADH | Inserts aquaporins

Question 31

Micturation

Answer 31

1. 200mL urine in bladder, stretch receptors send signal to the spinal cord (S2 and S3) 2. Parasympathetic reflex arc from spinal cord, stimulates contraction of detrusor muscle 3. Relaxation of internal urethral sphincter 4. This reflex predominates in infants

Question 32

Voluntary Control of Micturation

Answer 32

5. Micturition center in pons receives stretch signals and integrates cortical input (voluntary control) 6. Sends signal for stimulation of detrusor and relaxes internal urethral sphincter 7. To delay urination impulses sent through pudendal nerve to external urethral sphincter keep it contracted until you wish to urinate 8. Valsalva maneuver aids in expulsion of urine by increased pressure on bladder

Question 33

Incontinence

Answer 33

Lack of voluntary control over micturation

Question 34

Total Body Water

Answer 34

45%

Question 35

Fluid Compartments

Answer 35

``` 65% intracellular fluid 35% extracellular fluid 25% interstitial fluid 8% blood plasma and lymph 2% transcellular fluid ```

Question 36

Water Gain and Loss

Answer 36

About 2,500 mL/day

Question 37

Regulation of Intake

Answer 37

``` Dehydration Hypothalamic osmoreceptors Thirst Ingestion of water Rehydration ```

Question 38

Dehydration

Answer 38

``` Increased blood osmolarity Hypothalamus inhibits salivary glands Stimulates osmoreceptors (Angiotensin II and ADH) ```

Question 39

Regulation of Output

Answer 39

Most mechanisms adjust Na+ | ADH does NOT involve Na+ reabsorption, is inserts aquaporins into the collecting duct

Question 40

Hypovolemia

Answer 40

Na+ and H2O lost | Osmolarity does not change

Question 41

Electrolyte Balance

Answer 41

Maintenance is important to contribute to membrane potential and osmolarity of body fluids

Question 42

Sodium

Answer 42

Responsible for resting membrane potential Principal cation in ECF Most important solute for determining water distribution

Question 43

Hypernatremia

Answer 43

Hypertension, edema | > 145

Question 44

Hyponatremia

Answer 44

Usually the result of excess water, sweat and replace with plain water < 130