Overview of Kidney, Nephron Anatomy and Function Flashcards

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1
Q

Functions of the Urinary System

A
  1. REgulation of Body Fluid Volume - conserving or eliminating water
  2. Regulation of Fluid Osmolality and Composition - Na+, K+, Ca++, Cl-
  3. Waste Removal (metabolism by products - nitrogenous wastes(urea), acids)
  4. Endocrine - Renin(cascade for BP) Erythropoieten (RBC production)
  5. Territory/Sex marker
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2
Q

Components of Urinary System

A
  1. Vascular System
  2. 2 kidneys
  3. 2 ureters
  4. 1 bladder
  5. 1 urethra
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3
Q

Amount of plasma filtered per day

A

180 L or 45 gallons

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4
Q

Amount of Urine excreted per day

A

1.5 L

137 gallons per year, 10265 gallons per life

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5
Q

% of blood flow goint to the kidneys

A

25% of cardiac output

1250mL/min, 5mL/min/gram of kidney

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6
Q

Kidney

A

paired, bean shaped organ, 4.5 inches long, retroperitoneal sposition(Tt12-L3), ureters depart from the Hilus, functional unit is Nephron

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7
Q

Primary Kidney Function

A

conservation and filtration of fluid

cannot restore lost volume

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8
Q

Gross Anatomy

Main Kidney Parts

A
  1. Capsule
  2. Cortex
  3. Medulla
  4. Pelvis
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9
Q

Kidney

Capsule

A

provides protection to the Kidney

tough fibrous layer that surrounds the kidney

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10
Q

Kidney

Cortex

A

where ultrafiltration and erythropoietin production occur, contains cortical arches and renal columns

between the capsule and medulla

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11
Q

Renal Columns

A

consists of blood vessels and urinary tubes

medullary extension of renal cortex in between renal pyramids

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12
Q

Kidney

Medulla

A

8-18 renal pyramids, contains Nephrons

innermost part of the kidney

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13
Q

Renal Calyces

A

pacemaker cells that stimulate peristalsis which propels urine

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14
Q

Nephron

A

funcitonal unit, 1-3 million per kidney, 3 cm long

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15
Q

Functions of Nephron

A
  1. Filtration of Blood Plasma(concentration)
  2. Reabsorbtion of water, AA’s, sugar, salts(Acidification)
  3. Secretion of H, K ions

these funcitons allow urine concentration and acidification

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16
Q

Cortical Nephrons

A

start high in the cortex and have a short loop of henle that does not deeply penetrate the medulla

majority of Nephrons

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17
Q

Juxtaglomerular Nephrons

A

cells that produce Renin

produces renin in response to B1 receptors, decrease in renal profusion, decrease in NaCl concentration in the macula densa

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18
Q

5 Principle Nephron Parts

A
  1. Renal Corpuscle
  2. Proximal Concoluted Tubule
  3. Loop of Henla
  4. Distal Convoluted Tubule
  5. Collecting Duct
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19
Q

Renal Corpuscle

A

primary function is filtration

Renal Corpuslce = Glomerulus + Bowman’s Capsule

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20
Q

Glomerulus

A

fenestrated(leaky) capilary exchange unit, Filtration Funciton

simple squamous, basal lamina, podocytes, mesangial cells

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21
Q

Afferent Arteriole

A

incoming flow into glomerulus

smooth muscle that is resistant to Angiotensin 2(vasoconstrictor)

22
Q

Efferent Arteriole

A

outgoing flow from the glomerulus

only the kidney has capillaries that are drained by arterioles

smooth muscle that is activated by Angiotensin 2(vasoconstrictor)

23
Q

Bowman’s Capsule

A

collects fluid from the glomerulus

24
Q

Proximal Convoluted Tubule

A

85% Reabsorbtion of water, Na, AA, and glucose

glucose coupled with Na+ for transport

Glucose = Tm=375 mg/dl in men 300mg/dl in women, Tm=maximum amount to reabsorb glucose in urine

25
Q

What does glucose in urine signal?

A

Diabetes

26
Q

Loop of Henle

A

creates salt interstitum, ultimate goal is water reabsorbtion and creating more concentrated urine

27
Q

Counter Current Multiplier

A

salt concentraiton increases as it goes down, creates a concentration gradient

Loop of Henle

thin descending limb: water permeable
thick ascending limb: Na+ permeable

28
Q

Counter Current Exchanger

A

Vasa Recta/Peritubular Capillaries

29
Q

Disatal Convoluted Tubule

A

responsible for secretion, acidification, and reabsorbtion

helps with the Renin/Angiotensin/Aldosterone System

30
Q

Kidney

Secretion

A

the movement of selected molecules from the blood into the nephron

filters K+ with Aldosterone much of the time

31
Q

Excretion formula

A

Filtration - Reabsorbtion + Secretion

32
Q

Acidification

A

???

33
Q

Reabsorbtion

A

movement of filtered material from the lumen of the nephron to the blood

occurs when proximal tubule cells transport solutes out of the lumen, water follows via osmosis

34
Q

Macula Densa

A

specialized cells in the distal tubule wall that monitor fluid flow through the tubule

35
Q

JG Apparatus

A

region where the distal tubule of the nephron passes between afferent and efferent arterioles

36
Q

Renin

A

peptide secreted by juxtaglomular cells that converts angiotensinogin into angiotensin 1

37
Q

Collecting Duct

A

terminal region of the kidney tubule, permeable to water

last 15% of water reabsorbed

38
Q

ADH

A

Anti Diuretic Hormone, supraoptic nuclei of Hypothalmus, stored and released by Posterior Pituitary

39
Q

No ADH

A

87% total water reabsorbtion, would lead to 24L of excretion per day, Diabetes Isipidus,

alcohol inhibits ADH release

40
Q

Normal ADH levels

A

98.7% water reabsorbtion, 1.5L of excretion per day

41
Q

Maximum ADH

A

99.7% water reabsorbtion, 0.5L of excretion per day

42
Q

Osmo

Osmoreceptors

A

in the Hypothalmus, regulate ADH output

osmoreceptors shrink = increase plasma osmolality 1-2%, hypovolemia, increased thirst and ADH release

43
Q

Tubular Excretory Components

A
  1. Ureter
  2. Bladder
  3. Urethra
44
Q

Ureter

A

propels urine via peristaltic wave(ureters function without gravity), run obliquely thru bladder wall, forms valve(prevents backflow)

paired, 10-12 inches long, retroperitineal, 3 layers(mucosa, muscularis, fibrous)

45
Q

Bladder

A

detrusor muscle-smooth muscle,
Trigone: 2 ureter input + urethra outflow

in pelvis, posterior to pubic symphysis, male anterior to rectum, female anterior to uterus

46
Q

Urethra

A

2 parts
Internal Urethral Sphincter (smooth m.)
External Urethral Sphincter (skeletal m.)

47
Q

Female Urethra

A

excretory funciton only, emptys via gravity, infection prone

short - 1.5 inches,

48
Q

Male Urethra

A

excretory + reproductive function(joined by 2 ejaculatory tracts)

prostatic(travels through prostate), membranous(external urethral sphincter), cavernous(in Corpus Spongiosum)

49
Q

Micturition(urination)

A

bladdder fills, proprioceptors maintain tonus, involves both sympathetic and parasympathic paths, parasympathetic is more important.

200-300mL will make the individual aware of the desire to urinate

50
Q

Reflex Urination

A
  1. above 200mL of urine
  2. detrusor muscle contracts
  3. internal and external sphincters relax
  4. bladder empties

infants, spinal cord injuries

51
Q

Atonic Micturition

A

detrusor muscle tone lost

incontinence and dribbling

52
Q

Controlled Micturition

A

Cerebral Cortex inhibits contraction of detrusor muscle, relaxation of sphincters