17- Urinary System Flashcards

1
Q

Components of the urinary system

A

Kidneys
Ureters
Urinary Bladder
Urethra

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2
Q

Kidney functions (

A
  1. Excretion of urine (metabolic wastes= urea, uric acid, creatinine; foreign substances or their breakdown products)
  2. Regulation of total body water
  3. Regulation of electrolytes (Na, Cl)
  4. Control of acid-base balance (bicarbonate-carbonic acid)
  5. Endocrine secretion (Erythropoietin and Renin)
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3
Q

How much urine do you excrete a day

A

1-2 L/day

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4
Q

Erythropoietin and Renin

what do these endocrine secretions do?

A

Erythropoietin- stimulates blood cell formation

Renin- influences blood pressure

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5
Q

Gross anatomical features of the kidney

A

Bean-shaped, convex lateral surface, concave medial surface, posterior abdominal wall, retroperitoneal and dense connective tissue capsule

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6
Q

Describe Hilus of kidney

A

Indentation of medial border
Renal artery, vein, lymphatics and nerves enter and leave
Renal pelvis leaves

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7
Q

Describe Sinus of kidney

A

cavity that extends inward from the hills
surrounded by renal parenchyma
contains renal pelvis
remainder of sinus filled by loose connective tissue and fat

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8
Q

Describe renal pelvis

A

funnel-shaped expansion of proximal ureter

Major Calyces- 2-3 per kidney
Minor Calyces- 8-12 per kidney

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9
Q

Parenchyma of kidney

A

Cortex- outer dark layer

Medulla- inner lighter layer

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10
Q

Describe cortex of kidney

A

Medullary Ray- radially directed striations

Lobule- consists of a medullary ray and surrounding cortical tissue

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11
Q

Renal Blood Flow

A

1200 mL/min (20% of cardiac output)

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12
Q

Glomerular Filtration

A

125 mL/min

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13
Q

Urine Formation

A

1 mL/min

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14
Q

Medulla of kidney

A

Renal or medullary pyramid
Renal Columns (extensions of cortical tissue between medullary pyramids)
Lobe (consists of pyramid, its overlaying cortex and its surrounding cortex, i.e.: renal columns)

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15
Q

Rena/Medullary Pyramid

A

Base towards cortex
Papilla or apex projects into minor calyx
Area Cribrosa- tip of papilla perforated by 10-25 openings of collecting tubules

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16
Q

Blood Supply to kidney

A

Renal artery with segmental divisions

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17
Q

Interlobar arteries

A

in renal columns between pyramids

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18
Q

Arcuate arteries

A

arched over base of pyramids

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19
Q

Interlobular arteries

A

course parallel with medullary rays

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20
Q

Afferent arteriole

A

supplies blood to glomerular capillaries

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21
Q

Golumerulus

A

globular tuft of fenestrated (w/o diaphragms) capillaries

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22
Q

Efferent Arteriole

A

drains glomerular capillaries to the 2nd capillary bed, it’s a “portal arteriole”

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23
Q

2nd capillary bed

A

peritubular capillary network from cortical glomeruli

Has vasa recta from juxtamedullary glomeruli

24
Q

Vasa Recta (of 2nd capillary bed)

A

thin walled capillaries
Descending (toward papilla)- arterial limb
Ascending (toward renal surface)- venous limb
Form hairpin loops
Collectively called vascular bundle or rete mirabile

25
Peritubular capillaries, vasa recta, and sometimes glomerular capillaries drain into _________________
interlobular veins, or arcuate veins--> interlobular veins --> renal veins
26
Nephron
1. Renal (Malphighian) corpuscle (#1) - Glomerulus (capillary tuft) - Capsule (of Bowman) 2. Proximal tubule - Convoluted (#2) - Straight (descending thick limb, #3) 3. Thin limb of loop of Henle - Descending (#4) - Ascending (#5) 4. Distal tubule - Straight (ascending, thick limb #6) - Macular portion (#7) - Convoluted portion (#8) 5. Loop of Henle (#3, #4, #5, #6) - Thick descending limb (straight) - Thin descending limb - Thin ascending limb - Thick ascending limb (straight) 6. Cortical nephron 7. Juxtamedullary nephron
27
Cortical nephron
Located near the capsule, short loops of Henle, extend only into outer medulla
28
Juxtamedullary nephron
located near the medulla, long loops of Henle, extend well into the inner medullar and are active in water reabsorption and urine concentration
29
Collecting tubule and ducts (excretion of urine)
1. Arched portion- short in cortex (#9) | Straight or descending portion- from cortex to papilla
30
``` (Uriniferous tubule) # of Nephrons per kidney ```
1-2 million per kidney
31
Renal Corpuscle is made up of
glomerulus + Bowman's capsule
32
Glomerulus (Describe)
Globular tuft of type II (fenestrated, but no diaphragm) capillaries with thick basal lamina 1) Afferent arteriole 2) Efferent arteriole
33
Bowman's Capsule
Visceral layer- modified epithelial cells called podocytes Parietal layer- simple squamous epithelium, gradually increasing in height to become continuous with epithelium of proximal convoluted tubule Urinary (Bowman's) space- between viscera; and parietal capsule
34
Podocytes
Modified epithelial cells of the visceral layer of the Bowman's Capsule Stellate shape Closely applied to glomerular capillary endothelium Have radiating proceses: 1) Primary- large, few 2) Secondary- small, numbers (have foot processes or pedicles) Interdigitate with neighboring pedicles, for split pores (25 nm), slit pores cover slit membranes (6nm), prominent basal lamina
35
Mesangial cells
phagocytic cells located between capillaries; beep basal lamina clear
36
Vascular pole of renal corpuscle
point where afferent and efferent arteriole enter and leave the glomerulus
37
Urinary pole of renal corpuscle
point where parietal layer of capsule is continuous with proximal convoluted tubule
38
Filtration Barrier (3 parts)
1. Fenestrated Endothelium of glomerular capillaries, retains only cellular elements of blood (no diaphragms present) 2. Combined Basal Laminae of capillary endothelium and podocytes, retains only large molecules of blood (only continuous layer of filtration barrier) 3. Slit Pores (with slit membranes) between podocytes, retains only small molecules of blood
39
Proximal Tubule location and epithelium
Location: PCT located in area of parents renal corpuscle Simple cuboidal Brush border- conspicuous microvilli covering on luminal surface of pct (proximal conv. tubule) cells Basal Infoldings of plasma membrane
40
Basal infoldings of plasma membrane of PCT
creates striated appearance, increases surface area, many mitochondria, site of active Na transport
41
Thin limb of Loop of Henle location and epithelium
Location: medulla Epithelium: simple squamous, no brush border, resemble capillary
42
Distal Tubule epithelium- Straight (ascending) portion
has abrupt increase in thickness of epithelium from thin portion of proximal tubule Inner medulla contains only thin segments, collecting ducts and blood vessels Simple cuboidal, no brush border, prominent basal infoldings, site of active Cl transport, low H20 permeability
43
Distal Tubule epithelium- Macular portion
Specialized cells of distal tubule which come into contact with afferent and efferent arteriole of parents renal corpuscle Epithelium- Tall cuboidal to columnar, thinner cells than rest of distal tubule, nuclei appear crowded together
44
Distal Tubule epithelium- Convoluted portion
Many short loops, above region of parents renal corpuscle, no different in epithelium from straight portion of distal tubule, site of active Na transport, low H20 permeability
45
Collecting Tubule and larger collecting ducts (epithelium)
different from nephron Simple cuboidal (small ducts) to simple columnar (large ducts) distinctly outlined cells Darkly staining round nucleus Permeability under influence of ADH (antidiuretic hormone or vasopressin) released by neurohypophysis.
46
ADH causes
permeability of the collecting ducts to increase, leading to an increase in the reabsorption of water from the tubules and subsequently a more concentrated urine
47
Juxtaglomerular apparatus (JG)
Modified smooth muscles cells of afferent arteriole | Contain granules that have renin
48
Renin catalyzes
conversion of angiotensinogen to angiotensin I, which is converted to angiotensin II by another enzyme from the lung
49
Angiotensin II is a
potent renal and systemic vasoconstrictor (increases BP) Also stimulates aldosterone release by the adrenal cortex which causes reabsorption of Na and thus H2O, leading to an increase in total body water and blood pressure
50
JG Apparatus also consists of:
Macula densa of distal tubule
51
Function of JG apparatus
cells of macula densa sense NaCl concentration in distal tubule Macula densa cells mediate release of renin by JG cells effecting change in electrolytes, total body water and BP
52
Extrarenal Collecting System
Renal pelvis, ureters, urinary bladder, and urethra
53
Mucosa- epithelium
transitional epithelium for the most part; increases in thickness from ureter to urethra; impermeable to H2O and salts Lamina Propria- relatively dense
54
Muscularis
Inner longitudinal layer (opposite to GI tract) Middle circular layer (opposite to GI tract) Additional outer longitudinal layer from distal ureters to bladder (not present in GI tract) Adventitia
55
Nephron is responsible for
formation of urine