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A & P > objective 7 pt 2 > Flashcards

objective 7 pt 2 Flashcards

1
Q

basically blood plasma except the proteins

A

filtrate

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2
Q

what are the 3 processes that are involved in urine formation and adjustment of blood composition?

A

glomerular filtration
tubular reabsorption
tubular secretion

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3
Q

passive process, no metabolic energy required
hydrostatic pressure forces fluid and solutes through filtration membrane into glomerular capsule
no reabsorption into capillaries of glomerulus occurs

A

glomerular filtration

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4
Q

porous membrane between blood and interior of glomerular capsule
allows water and solutes smaller than plasma proteins to pass

A

filtration membrane

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5
Q

what are the 3 layers of the filtration membrane

A

fenestrated endothelium
basement membrane
foot processes of podocytes

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6
Q

allows all blood components except blood cells to pass through

A

fenestrated endothelium

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7
Q

physical barrier that blocks all but smallest proteins while still allowing other solutes to pass

A

basement membrane

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8
Q

contain filtration slits which repel macromolecules

A

foot processes of podocytes

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9
Q

blood enters the glomerulus
filterable blood components, such as water and nitrogenous waste, will move towards the inside of the glomerulus
non-filterable conponents, such as RBCs and plasma proteins, will exit via the efferent arteriole
the filterable components accumulate in the glomerulus to form the glomerular filtrate

A

filtration

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10
Q

forces that promote filtrate formation

A

outward pressure

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11
Q

essentially glomerular blood pressure
chief force pushing water, solutes out of blood

A

hydrostatic pressure in glomerular capillaries

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12
Q

forces inhibiting filtrate formation

A

inward pressure

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13
Q

filtrate pressure in capsule; 15 mm Hg

A

hydrostatic pressure in capsular space

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14
Q

“pull” of proteins in blood; 30 mm Hg

A

colloid osmotic pressure in capillaries

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15
Q

sum of forces
pressure responsible for filtrate formation

A

net filtration pressure

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16
Q

volume of filtrate formed per min by both kidneys

A

glomerular filtration rate

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17
Q

what is GFR directly proportional to?

A

net filtration pressure
total surface area
filtration membrane permeability

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18
Q

primarily pressure is glomerular hydrostatic pressure

A

net filtration pressure

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19
Q

available for filtration

A

total surface area

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20
Q

much more permeable than capillaries

A

filtration membrane permeability

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21
Q

renal autoregulation
enables kidneys to maintain constant blood flow and GFR

A

intrinsic controls and GFR

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22
Q

what are the two types of renal autoregulation?

A

myogenic mechanism
tubuloglomerular feedback mechanism

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23
Q

local smooth muscle
increased BP causes muscle to stretch, leading to constriction of afferent arterioles
restricts blood flow into glomerulus
protects glomeruli from damaging high BP
decreased systemic BP causes dilation of afferent arterioles and raises glomerular hydrostatic pressure

A

myogenic mechanism

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24
Q

with an increased concentration of NaCl in filtrate in the distal tubules, it causes a release of adenosine from the macula densa
cells
initiates a cascade of events that brings GFR to an appropriate level

A

tubuloglomerular feedback mechanism

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25
Q

neural and hormonal mechanisms
regulate GFR to maintain systemic blood pressure
override renal intrinsic controls if blood volume needs to be increased

A

extrinsic controls

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26
Q

renal blood vessels dilated
renal autoregulation mechanisms prevail

A

sympathetic nervous system under normal conditions at rest

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27
Q
  • Norepinephrine released by sympathetic nervous system and
    epinephrine is released by adrenal medulla, causing:
  • Systemic vasoconstriction, which increases blood pressure
  • Constriction of afferent arterioles, which decreases GFR
  • Blood volume and pressure increases
A

sympathetic nervous system under abnormal conditions

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28
Q

main mechanism for increasing BP. low BP causes the release of renin from granular cells of the juxtaglomerular complex

A

renin-angiotensin-aldosterone mechanism

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29
Q

what are the 3 pathways that stimulate granular cells?

A

sympathetic nervous system
activated macula dens cells
reduced stretch

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30
Q

part of baroreceptor reflex, renal sympathetic nerves activate receptors that cause granular cells to release renin

A

sympathetic nervous system

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31
Q

occurs when filtrate NaCl concentration is low. signal grandular cells to release renin

A

activated macula dens cells

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32
Q

grandular cells ac as mechanoreceptors. reduced MAP reduced tension in grandular cells plasma membranes stimulates them to release more renin

A

reduced stretch

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33
Q

quickly reclaims most of contents from filtrate and returns them to blood via a selective transepithelial process
process that moves solutes and water out of the filtrate and back into your bloodstream

A

tubular reabsorption

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34
Q
  • Na+ is most abundant cation in filtrate
  • Transport of Na+ out of the tubule cell via primary
    active transport by a Na+-K+ ATPase pump in the
    basolateral membrane
  • Na+ into the interstitial space
  • Na+ is then swept by bulk flow of water and
    solutes into peritubular capillaries.
  • Organic nutrients reabsorbed by secondary active
    transport are cotransported with Na+
A

sodium transport

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35
Q
  • Movement of Na+ and other solutes creates osmotic
    gradient for water
  • Water is reabsorbed by osmosis into the peritubular
    capillaries, aided by transmembrane proteins called
    aquaporins (act as water channels)
A

reabsorption of water

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36
Q
  • Aquaporins are always present in PCT
  • Forces body to reabsorb water regardless if over or
    under hydrated
A

obligatory water reabsorption

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37
Q
  • Aquaporins are inserted in collecting ducts only if
    ADH is present
A

facultative water reabsorption

38
Q
  • Solute concentration in filtrate increases as water is
    reabsorbed
  • Creates a concentration gradient for solutes, which
    drive their entry into the tubule cell and peritubular
    capillaries
  • Fat-soluble substances, some ions, and urea will follow
    water into peritubular capillaries down their
    concentration gradients
  • For this reason, lipid-soluble drugs and environmental
    pollutants are reabsorbed even though it is not
    desirable
A

passive tubular reabsorption of solutes

39
Q

Site of most reabsorption
* All nutrients, such as glucose and amino acids,
are reabsorbed
* 65% of Na+ and water reabsorbed
* Many ions/electrolytes
* Almost all uric acid
* About half of urea (later secreted back into
filtrate)

A

proximal convoluted tubule

40
Q

H2O can leave, solutes cannot (permeable to water)

A

descending limb

41
Q

H2O cannot leave, solutes can (impermeable to water)

A

ascending limb

42
Q

reabsorption is hormonally regulated in these areas

A

distal convoluted tubule and collecting duct

43
Q
  • Released by posterior pituitary gland
  • Causes formation of aquaporins in collecting ducts,
    increasing water reabsorption
  • Increased ADH levels cause an increase in water
    reabsorption
A

antidiuretic hormone

44
Q
  • Released by adrenal cortex in response to
    decreased blood volume/BP or hyperkalemia
  • Targets collecting ducts and DCT
  • Promotes Na+ reabsorption (water follows)
  • As a result, little Na+ leaves body
  • Without aldosterone, daily loss of filtered Na+
    would be 2%, which is incompatible with life
A

aldosterone

45
Q

what are the functions of aldosterone?

A

increase blood pressure and
decrease
K+ levels

46
Q
  • Reduces blood Na+, resulting in decreased blood
    volume and blood pressure
  • Released by cardiac atrial cells if blood volume or
    pressure elevated
A

atrial natriuretic peptide

47
Q
  • Acts on DCT to increase Ca2+ reabsorption
A

parathyroid hormone

48
Q

is the opposite of reabsorption
* Occurs almost completely in DCT
* Selected substances are moved from peritubular
capillaries through tubule cells out into filtrate
* K+, H+, NH4+, creatinine, organic acids and bases
* Substances synthesized in tubule cells also are
secreted
* Helps control blood pH and acid base balance of
body by selectively secreting electrolytes

A

tubular secretion

49
Q

what is tubular secretion important for?

A
  • Disposing of substances, such as drugs or metabolites,
    that are bound to plasma proteins
  • Eliminating undesirable substances that were passively
    reabsorbed (example: urea and uric acid)
  • Ridding body of excess K+ (aldosterone effect)
  • Controlling blood pH by altering amounts of H+ or HCO3–
    in urine
50
Q

substance not reabsorbed,
so water remains in urine; for example, in
diabetic patient, high glucose concentration pulls
water from body

A

osmotic diuretics

51
Q

inhibit medullary gradient formation

A

loop diuretics

52
Q

urine is examined for signs of disease
can also be used to test for illegal substances

A

urinalysis

53
Q

volume of plasma the kidneys can clear of a particular substance in a given time
used to determine GFR

A

renal clearance

54
Q

what is the chemical composition of urine

A

95% water 5% solutes

55
Q

largest solute component

A

urea

56
Q

from nucleic acid metabolism

A

uric acid

57
Q

metabolite of creatine phosphate found in skeletal muscle

A

creatinine

58
Q

what are they physical characteristics of urine?

A

color and transparency
odor
pH
specific gravity

59
Q

Clear
* Cloudy may indicate urinary tract infection
* Pale to deep yellow from urochrome
* Pigment from hemoglobin breakdown
* Yellow color deepens with increased concentration
* Abnormal color (pink, brown, smoky)
* Can be caused by certain foods, bile pigments,
blood, drugs

A

color and transparency of urine

60
Q
  • Slightly aromatic when fresh
  • Develops ammonia odor upon standing as
    bacteria metabolize urea
  • May be altered by some drugs or vegetables
  • Disease may alter smell
  • Patients with diabetes may have acetone
    smell to urine
A

odor of urine

61
Q
  • Urine is slightly acidic (~pH 6, with range of 4.5 to
    8.0)
  • Acidic diet (protein, whole wheat) can cause drop in
    pH
  • Alkaline diet (vegetarian), prolonged vomiting, or
    urinary tract infections can cause an increase in pH
A

pH of urine

62
Q
  • Ratio of mass of substance to mass of equal volume
    of water (specific gravity of water = 1)
  • Ranges from 1.001 to 1.035 because urine is made
    up of water and solutes
  • Normally excrete approx. 450 ml in 24 hours (30
    ml/hr)
A

specific gravity of urine

63
Q

slender tubes that convey urine from kidneys to bladder
retroperitoneal
enter base of bladder through posterior wall

A

ureters

64
Q

what are the 3 layers of the ureters?

A

mucosa
muscularis
adventitia

65
Q

consists of transitional epithelium

A

mucosa

66
Q

smooth muscle sheets contract in response to stretch

A

muscularis

67
Q

gravity alone is not enough; must also be pushed by peristaltic wave action of smooth muscle

A

propels urine into bladder

68
Q

outer fibrous connective tissue

A

adventitia

69
Q
  • Smooth, collapsible, Muscular sac for temporary
    storage of urine
  • Retroperitoneal, on pelvic floor posterior to pubic
    symphysis
A

urinary bladder

70
Q

prostate inferior to bladder neck

A

males urinary bladder

71
Q

anterior to vagina and uterus

A

females urinary bladder

72
Q
  • Smooth triangular area outlined by openings
    for
    ureters and urethra
  • Infections tend to persist in this region
A

trigone

73
Q

what are the layers of the bladder wall?

A

mucosa
muscular layer
fibrous adventitia

74
Q

transitional epithelial mucosa

A

mucosa

75
Q

thick detrusor muscle that contains 3 layers of smooth muscle

A

muscular layer

76
Q

except on superior surface where it is covered by peritoneum

A

fibrous adventitia

77
Q
  • Collapses when empty
  • Mucosa folds (Rugae)
  • Expands and rises superiorly during filling
    without significant rise in internal pressure
  • Moderately full bladder is ~12 cm long (5 in.) and
    can hold ~ 500 ml (1 pint)
  • Can hold twice that amount if necessary but
    can burst if over distended
A

urine storage capacity

78
Q
  • Muscular tube that drains urinary bladder
  • Mucosal lining consists mostly of pseudostratified
    columnar epithelium, except:
  • Transitional epithelium near bladder
  • Stratified squamous epithelium near
    external urethral orifice
A

urethra

79
Q
  • Involuntary (smooth muscle) at bladder-urethra
    junction
  • Controlled by autonomic nervous system to keep
    closed when urine not being passed.
  • Contracts to open
A

internal urethral sphincter

80
Q
  • Voluntary (skeletal) muscle surrounding urethra as it
    passes through pelvic floor
A

external urethral sphincter

81
Q

tightly bound to anterior vaginal wall

A

female urethra

82
Q

anterior to vaginal opening; posterior to clitoris

A

external opening

83
Q

carries semen and urine

A

male urethra

84
Q

what are the 3 named regions of the male urethra?

A

prostatic urethra
intermediate part of the urethra
spongy urethra

85
Q

within prostate

A

prostatic urethra

86
Q

passes through urogenital diaphragm from prostate to beginning of penis

A

intermediate part of the urethra

87
Q

passes through penis; opens via external urethral orifice

A

spongy urethra

88
Q

act of emptying the bladder

A

micturition also called urination or voiding

89
Q

what are the 3 simultaneous events that must occur for micturition?

A
  1. Contraction of detrusor muscle by ANS
  2. Opening of internal urethral sphincter ANS
  3. Opening of external urethral sphincter by
    somatic nervous system
90
Q
  • Distension of bladder activates stretch receptors
  • Causes excitation of parasympathetic neurons in
    reflex center in sacral region of spinal cord
  • Leads to contraction of detrusor and opening
    (contraction) of internal sphincter
  • Inhibition of somatic pathways to external
    sphincter allow its relaxation and opening
A

reflexive urination

A & P (21 decks)

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