Chapter 25: Urinary System Flashcards

1
Q

Functions of Urinary system

A

regualtes volume and chemical makeup of extracellular and intracellular fluids; ensures long term acid base balance; excretes metabolic (nitrogenous) wastes, drugs and toxins; produces erythropoietin (hormone regulating RBC produciton) and renin (enzyme regualting BP); converts vit D to its active form; carries out gluconeogeneiss during prolonged fasting

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2
Q

Location of Kidneys

A

superior lumbar region (between T12 and L3); retroperitenial

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3
Q

What are the three supportive tissues that surround the kidneys?

A

renal fascia; perirenal fat capulse; fibrous capsule

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4
Q

Renal Fascia

A

anchors kidneys to surround structures

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5
Q

Perirenal Fat Capsule

A

cushions the kidneys

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6
Q

Fibrous Capsule

A

prevents infections from spreading to kidneys

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7
Q

External Anatomy of Kidney

A

ureter, renal blood vessels, lymphatics and nerves enter/exit kidney at renal hilum; adrenal gland sits atop kidney

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8
Q

3 Regions of the Kidney

A

renal cortex; renal medulla and renal pelvis

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9
Q

Renal Cortex

A

outermost; has granular appearance

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10
Q

Renal Medulla

A

contains renal pyramid; has striated pyramid

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11
Q

Renal Pelvis

A

funnel shaped tube continuous with ureter

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12
Q

Urine drains…

A

continurously from each pyramid; minor calyx to major calyx to renal pelvis to ureter

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13
Q

ADD BLOOD SUPPLY

A
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14
Q

Blood passes thru…

A

TWO capillary bed

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15
Q

Nephrons

A

structural and functional units of the kidney; process blood to form urine; consists of renal corpuscle and renal tubule

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16
Q

Renal Corpuscle

A

located within renal cortex; consists of two parts glomerulus and glomerular capsule

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17
Q

Glomerulus

A

ball of fenestrated capillaries; fed by afferent arteriole; drianed by efferent arteriole; filters blood to form filtrate; capillaries are higher in pressure compared to other parts of body

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18
Q

Glomerular Capsule is two layered

A

parietal layer- simple squamous epithelium; visceral layer- consists of podocytes (branching epithelial cells with foot processes that adhere to glomerulus); filtrate passes thru filatarion slits into glomerular capsular layers (cells and lg proteins can not pass)

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19
Q

Renal Tubule

A

located in cortex and medulla; consists of 3 parts- proximal convoluted tubule, nephron loop, and distal convoluted tubule

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20
Q

Proximal Convoluted Tubule

A

PCT; continuous with glomerular capsular space; confined to cortex; wall is simple cuboidal epithelium with dense microvilli (brush border)

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21
Q

Nephron Loop

A

consists of descending and ascending limbs; extend into medulla; wall of thick segment is simple cuboidal epithelium; wall of thin segment is simple squamous

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22
Q

Distal Convoluted Tubule

A

DCT; confined to cortex; wall is thin layer of simple cuboidal epithelium with few microvilli

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23
Q

Collecting Ducts

A

not part of nephron; receive filtrate from nephrons and have 2 cell types; princuple cells- maintain water and NA balance and intercalated cells- maintain acid base balance of blood

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24
Q

Two Types of Nephrons Exist

A

Cortical nephrons and juxtamedullary nephrons

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25
Q

Cortical Nephrons

A

85%; glomerulus in outer cortex; short nephron loops; efferent arteriole empties into peritubular capillary bed

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26
Q

Juxtamedullary Capillary Bed

A

15%; glomerulus nearer cortex (medulla junction); long nephron loops; efferent arteriole empties inot vasa recta capillary bed; play major role in forming concentrated urine

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27
Q

Juxtaglomerular Complex

A

JGC; region of nephron where the afferent arteriole contacts the distal portion of the ascending limb; consists of three populations of cells- granular cells, macula densa and extraglomerular mesangial cells

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28
Q

Granular Cells

A

modified smooth muscle cells in wall of afferent arteriole; function as mechanoreceptors to monitor BP; secrete renin (enzyme)

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29
Q

Macula Densa

A

modified epithelial cells in ascending limp; function as chemoreceptors to monitor NaCl in filtrate

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30
Q

Extraglomerular Mesangial Cells

A

sandwhiched between afferent arteriole and macula densa; involved in cross talk

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31
Q

What three processes are involved with urine formation?

A

glomerular filtration; tubular reabsorption; tubular secretion

32
Q

Glomerular Filtration

A

occurs within renal corpuscles; passive, non selective process; hydrostatic pressure forces fluids and solutes thru a filatration membrane; produces a cell and protein free filtrate

33
Q

Filtrate membrane consists of three layers..

A

fenerstrated endothelium of glomerular capillaries; basement membrane; foot processes of podocytes of the glomerular capsule

34
Q

Glomerular Mesangial Cells

A

remove macromolecules that clog the filtration membrane

35
Q

Hydrostatic Pressure in Glomerular Capillaries

A

HPgc = 55 mmhg; pushes water and solutes out of glomerulus into capsular space

36
Q

Hydrostatic Pressure in Capsular Space

A

HPcs=15 mmhg; pushes water and solutes out of capsular space in glomerulus

37
Q

Osmotic Pressure in the Glomerulus

A

OPgc= 30 mmhg; blood proteins pull water in glomerulus

38
Q

Net Filtration Pressure =

A

(NFP); outward pressures - inward pressures = HPgc - (HPcs + OPgc) = 55 - ((15+30)= 10 mmhg

39
Q

Glomerular Filtration Rate

A

GFR; volume of filtrate formed per min by both kidneys; normal = 120-125 ml/min

40
Q

GFR determined primarily by..

A

HPgc

41
Q

dilation of afferent arteriole (constriction of efferent arteriole) does what to GFR

A

increases it

42
Q

Constriction of afferent arteriole ( or dilation of efferent arteriole) does what to GFR

A

decreases it

43
Q

What are the two types of control that regulates GFR?

A

intrinsic and extrinsic

44
Q

Intrinsic Control

A

renal autoregulation; kidney adjusts its own resistance to blood flow; involves two mechanisms that directly regulate GFR- myogenic mechanism (targets smooth muscle of afferent arteriole) and tubuloglomerular feedback mechanism (directed by macula densa of cells of the JGC); regulates when mean arterial pressure is 80-180 mmhg (so in a relatively normal range)

45
Q

Extrinsic Control

A

override intrinsic controls if mean arterial pressure is <80 or >180 mmhg; involves 2 mechanisms that indirectly regulate GFR- neural mechanism (SNS) and hormonal mechanism (renin-angiotensis-aldosterone mechanism)

46
Q

Tubular Reabsorption

A

process of reabsorbing (actively or passively) selected materials from renal tubules and collecting ducts, returining them to the blood stream; most reabsorption occurs from PCT; reabsorption in DCT and collecting tubes is regulated by hormones

47
Q

ADH

A

targets collecting ducts; increase h20 reabsorption

48
Q

Aldosterone

A

targets DCT and collecting ducts; increase sodium and h20 reabsorption

49
Q

Atrial Natriuretic Peptide

A

ANP; targets collecting ducts; decreases na and h20 absorption

50
Q

PTH

A

targets DCT ; increase ca reabsorption

51
Q

Tubular Secretion

A

active process of moving selected materials from the peritubular capillaries into the filtrate for elimination in urine; diposes of certain drugs; eliminates undesirable substances (urea, uric acid); rids body of excess k; controls blood pH (H and HCO3)

52
Q

Osmotic Gradient

A

reason kidneys have the ability to generate dilute and concentrated urine; ranges from 300 (cortex) - 1200 (pelvis) milliosmoles in renal medulla

53
Q

Diuretics

A

increases water output; given to people who tend to retain fluid (diabetics, heart failure, increased BP)

54
Q

Normal Output of Urine

A

800-1200 ml/day

55
Q

Chemical Composition of Urine

A

h2o (95%) and solutes (5%); nitrogenous wastes (urea, uric acid); ions (na, k, po3, so4, ca, mg, hco3)

56
Q

Urinalysis

A

may reveal presences of abnormal substances ADD THESE

57
Q

Physical Characteristics of Urine

A

transparent (cloudiness indicates UTI); yellow color due to eurochrome; slightly aromatic; pH ~6 (ranges from 4.5-8); specific gravity (solute concentration) 1.001-1.035

58
Q

Ureters

A

muscular tubes transporting urine from kidneys to urinary bladder; mucosa is transitional epithelium; muscularis has additional extern longitudinal layer in lower 1/3

59
Q

Urinary Bladder

A

collapsible, muscular sac that stores urine temporarily; 3 layers - mucosa: transitional epithelium; muscularis: internal, circular and external collectively called detrusor muscle; adventitia or serosa (depends on area); mucosa of empty bladder forms folds called rugae; ureters penetrate posterior bladder wall so that bladder pressure forces ends of ureters to close (prevents backflow)

60
Q

Trigone

A

triangular area outlined by opening of ureters and urethra; area most infected

61
Q

Urethra

A

muscular tube transporting urine from bladder to exterior; mucosa transitions from transitional epithelium to pseudostratified columnar to stratified squamous

62
Q

Internal Urethral Sphicter

A

smooth muscle; located at bladder-urethra junction; controlled by ANS

63
Q

External Urethral Sphincter

A

skeletal muscle; at urogenital diaphragm; controlled by somatic NS

64
Q

Female Urethra

A

1.5 in long; transports urine only

65
Q

Male Urethra

A

8 in long; transports urine and semen; subdivided into 3 regions (prostatic, membranous, penile)

66
Q

Micturition

A

aka urination, voiding; 3 simultaneous events occur- detrusor muscle contracts, internal urethral sphincter relaxes, external urethral sphincter relaxes; controlled by pontine micturition center and pontine storage center

67
Q

Micturition in Infants

A

stretching of bladder initaties a spinal reflex but they can not control it; between ages 2-3 brain can override reflexive urination

68
Q

Pyelerphritis

A

kidney infection

69
Q

Glomerulonephritis

A

inflammation of glomeruli

70
Q

Cystisis

A

bladder infection; experience painful urination (dysuria) and in females usually caused by fecal bacteria

71
Q

Urethritis

A

infection of urethra

72
Q

Renal Calculi

A

kidney stones; caused when crystals form from ca, mg, or uric acid

73
Q

Chronic Renal Disease

A

GFR less than 60 ml/min for at least 3 months; leading cuase is diabetes mellitus (44%) followed by hypertension (28%)

74
Q

Auria

A

urinary output less than 50 ml per day (kidneys must process 400-500 per day to excrete nitrogenous wastes)

75
Q

Renal Failure

A

GFR less than 15 ml / min; treatment- hemodialysis or transplant