Urinary System Flashcards
(107 cards)
1
Q
What are the fluid compartments of the body
A
Intracellular fluid compartment (2/3) and extracellular fluid compartment (1/3)
2
Q
What is intracellular fluid compartment?
A
All fluid within the body’s cells
3
Q
What is extra cellular fluid compartment?
A
Plasma, interstitial fluid, lymph, cerebrospinal fluid, synovial fluid, aqueous and vitreous humors, water (solvent)
4
Q
Describe movement of solutes and water in body
A
Fluid movement between compartments is constant and depends on osmotic and hydrostatic pressures
5
Q
Major function of the kidneys (6)
A
Regulate total volume of water in the body and the total concentration of solutes
Regulate concentration of ions in the extra cellular fluids
Regulate long term acid base balance
Excrete metabolic wastes and foreign substances
Producing hormones
Converting vitamin D to its active form
6
Q
What is the gross anatomy of kidney
A
Renal cortex and renal medulla
7
Q
What is renal cortex?
A
Superficial layer with granular appearance
8
Q
Sections of renal medulla (3)
A
Medullary (renal) pyramids
Renal columns
Lobes
9
Q
Medullary (renal) pyramids
A
Cone shaped tissue that appear striped due to parallel bundles of urine collecting tubules and capillaries
10
Q
Renal columns
A
Inward extensions of cortex separating pyramids
11
Q
Lobes
A
Pyramid surrounded by cortical tissue
12
Q
Parts of the nephron (2)
A
Renal corpuscle and renal tubule
13
Q
Renal corpuscle function
A
Responsible for filtering the blood and forming pre urine
14
Q
Renal Tubule Function (3)
A
Adjusts contents of pre urine to form urine. It’s long length increases processing capability
Removes 99% of water from pre urine and returns it to the blood (concentrates urine)
Adjusts ion levels and ph
15
Q
How much total cardiac output does the kidney receive
A
1/4 total cardiac output (blood)
16
Q
Blood supply through kidney
A
Abdominal aorta
Renal artery
Every lobe
Cortex
Afferent arterielle
Nephron
Renal vein
Inferior vena cava
17
Q
Parts of the urinary system which urine flows after leaving kidney
A
Ureters
Urinary bladder
Urethra
18
Q
Subdivisions of renal corpuscle (2)
A
Glomerulus and glomerular capsule
19
Q
Glomerulus
A
Capillary bed
20
Q
Glomerular capsule
A
Cup surrounding glomerulus
21
Q
Subdivisions of renal tubule (3)
A
Proximal convoluted tubule
Nephron loop (loop of henle)
Distal convoluted tubule
22
Q
Proximal convoluted tubule
A
Leads out of glomerular capsule
23
Q
Nephron loop (loop of henle)
A
Descending limb into medulla
Ascending limb back to cortex
24
Q
Distal convoluted tubule
A
Leads to collecting duct
25
Collecting duct (nephron)
Collects from many nephrons and completes modification of urine
26
What are 3 major renal processes responsible for urine formation
Glomerular filtration
Tubular reabsorotiom
Tubular secretion
27
Glomerular filtration
Dumps cell free and protein free blood Filtrate into the container (glomerular capsule or bowman’s capsule)
28
Tubular reabsorption
Reclaims what the body needs to keep (from tubule to blood)
29
Tubular secretion
Selectively adds to the filtrate (from blood to tubule)
30
Excretion
Term used to describe the elimination of finished urine from body
31
Describe the structure of filtration membrane (3 layers)
fenestrated endothelium
Basement membrane
Filtration slits between the foot processes of podocytes
32
Fenestrated endothelium (of glomerular capillary)
Allows passage of everything but blood cells
33
Basement membrane
Repels negatively charged macromolecules (plasma proteins)
34
Filtration slits between the foot processes of podocytes (visceral layer of glomerular capsule)
Slit diaphragm cover filtration slits adding a final barrier to macromolecules
Glomerular mesangial cells phagocytize debris caught between layers
35
“Ultrafiltrate of blood plasma”
In healthy nephrons, filtrate contains anything that is in blood plasma except cells and proteins
36
What forces promote or oppose glomerular filtration (2)
Hydrostatic pressure
Osmotic pressure
37
Hydrostatic pressure
Pressure of fluid against walls of vessel
38
Osmotic pressure
Pressure exerted by particles in the blood which tend to “pull” water into the vessel l or space
39
Proximal Convoluted tubule histology
simple cuboidal epithelium with microvilli
40
Nephron Loop - thin descending limb Histology
simple squamous cells
41
Nephron Loop - thick ascending limb histology
simple cuboidal cells
42
Distal Convoluted tubule histology
simple cuboidal epithelium with very few microvilli
43
peritubular capillaries
efferent arteriole gives rise to peritubular capillary bed
surround PCT and DCT in cortex and will reclaim/reabsorb most of the solutes and water from the filtrate
44
Vasa recta
Efferent arteriole gives rise to vasa recta - long straight capillaries
follow nephron loop deep into medulla - maintain osmotic gradient that makes it possible to concentrate urine
45
transport maximum
number of transport proteins available in tubule cell membrane
46
Secondary active transport
as Na+ diffuses across the membrane through a membrane cotransporter protein, it drives glucose against its concentration gradient into the cell
47
Where are secondary active transport proteins located?
Apical surface of the cuboidal cells of the proximal convoluted tubule (PCT)
48
Where are sodium potassium pumps located
Basal Surface of the cuboidal cells of the proximal convoluted tubule (PCT)
49
Proximal is always in ____
osmotic equilibrium with surrounding interstitial fluid and blood in peritubular capillaries
50
Proximal convoluted tubule function
65-70% of the filterest Na+, K+ os reabsorbed, plus many other electrolytes
100% of the filtered glucose is reabsorbed
100% of the filtered amino acids are reabsorbed
water follows by osmosis
some secretion occurs
51
Proximal Convoluted tubule functions happen ____?
automatically and are not regulated
52
Tubular reabsorption
reclaims what the body needs to keep (from tubule to blood) which is almost everything
53
Tubular secretion
selectively adds to the waste container (from blood to tubule)
54
Medullary Osmotic gradient
created by an increasing osmotic gradient extending through whole renal medulla
55
Glomerular filtration rate
volume of filtrate/min formed by all glomeruli in the kidneys
56
3 factors that modify glomerular filtration rate (GFR)
Net filtration pressure
surface area of all glomeruli
filtration membrane permeability
57
Net filtration rate
main controllable factor
glomerular hydrostatic pressure biggest influence - change diameter of arterioles
58
renal autoregulation
act locally within the kidney to maintain GFR despite changes in systemic blood pressure
59
Myogenic mechanism
smooth muscle reflex contracts when stretched and relaxes when not stretched, an inherent property of smooth muscle
60
Tubuloglomerular feedback mechanism
directed by the macula densa cells in the juxtaglomerular apparatus macula densa cells are sensitive to filtrate NaCl goes down and the concentration of NaCl in the ascending limb of loop goes up
61
what are the neural and hormonal controls of glomerular filtration
nervous regulation (sympathetic nervous system)
Hormonal regulation (renin-angiotensin-aldosterone mechanism)
62
What are the effects of angiotensin II?
vasoconstriction
stimulation of aldosterone release
stimulates Na/Cl absorption at PCT
Stimulates thirst
63
What are 3 hormones affecting BP and volume
aldosterone
antidiuretic hormone
atrial natriuretic peptide (ANP)
64
How does aldosterone regulate water and sodium levels?
it reabsorbs Na so it increases blood volume and BP
65
How does antidiuretic hormone regulate water and sodium levels?
it reabsorbs water so decrease extracellular fluid osmolality
66
how does atrial natriuretic peptide regulate water and sodium levels?
It decreases BP and blood volume
suppress the release of ADH, aldosterone and renin
67
What are the mechanisms that regulate water and sodium levels in the body?
No receptors
sodium-water balance is linked to BP and blood volume control mechanism
Changes in BP or volume trigger neural and hormonal controls to regulate Na+ content
68
why is the medullary osmotic gradient important?
without osmotic gradient, we would never be able to concentrate urine over 300 mOsm
69
What is the role of ADH in the medullary osmotic gradient?
ADH determines whether water can be reabsorbed by inserting aquaporins in the collecting duct cells
70
What is the role of urea in medullary osmotic gradient?
waste product, but is solute that aids in formation of osmotic gradient
urea "cycles" between collecting ducts, interstitium and ascending loop
71
What is the role of diuretics in the medullary osmotic gradient?
increase urine output
72
how does alcohol affect urinary system?
decreases ADH release
73
How does caffeine affect urinary system
it increases GFR
decreases Na reabsorption
74
How do loop diuretics affect the urinary system?
inhibit formation of osmotic gradient by inhibiting pumps in ascending limb
75
what is the flow of urine after the kidneys
Ureter
urinary bladder
urethra
76
What is the structure of the ureter
3 layers
mucosa
muscularis
adventitia
77
what is the structure of the urinary bladder
3 layers
mucosa
muscularis
adventitia or serosa
78
what is the structure of the urethra
internal urethral sphincter
external urethral sphincter
79
where does tubular reabsorption happen?
Proximal convoluted tubule
descending limb of nephron loop
ascending loop of nephron
Distal convoluted tubule
collecting duct
80
What substances are absorbed during tubular reabsorption
all nutrients
electrolytes
Na+
water
Solutes (Na+ K+ Cl-)
Antidiuretic hormone
aldosterone
atrial natriuretic peptide
parathyroid hormone
81
Where does tubular secretion happen?
Proximal convoluted tubule
sometime distal tubule
82
What are the main substances secreted during tubular secretion
Drugs and drug metabolites
urea, uric acid, nitrogenous wastes
creatine
excess K+
Excess H+ is secreted when blood is too acidic
83
What is the normal PH of urine?
4.5-8 (average 6)
84
What is the normal specific gravity of urine?
1.003-1.030
85
What is the osmotic concentration of urine?
855-1335 mOsm/L
86
What is the water content of urine
93-97%
87
Average volume of urine?
700-2000 mL/day
88
what is the normal color, clarity and odor of urine
pale yellow
clear
odor varies
89
What is the bacterial content of urine
none
90
What is renal clearance?
volume of plasma from which the kidneys clear a particular substance in one minute
91
Why is inulin use to estimate GFR?
inulin is not secreted or absorbed which means that rate at which inulin shows up in urine is the same as glomerular filtration rate (GFR)
92
Why is creatine used to estimate GFR?
produced at a constant rate, little is reabsorbed, a small amount is secreted
93
If clearance value is equal to inulin...
substance is filtered but neither reabsorbed or secreted
94
if clearance value is less than inulin...
substance is filtered but at least some is reabsorbed by tubule cells
95
if clearance value is greater than inulin...
substance is filtered but also being secreted by subtle cells and added to the filtrate
96
what are the 3 major chemical buffer systems?
carbonic acid-bicarbonate buffer system
phosphate buffer system
protein buffers
97
what is the carbonic acid-bicarbonate system?
extracellular fluid compartment
carbon dioxide + water --> carbonic acid --> bicarbonate ion + hydrogen ion
98
what is the phosphate buffer system
intracellular fluid compartment and urine
uses a strong acid (HCl) or a strong base (NaOH)
99
what is the protein buffer system
both ICF and ECF
individual amino acids on a protein can donate or accept H+ allowing it to function as a weak acid or base as needed
100
what is the relationship between PCO2 and bicarbonate ions to blood PH
the net effect is that strong acid is converted to a weak acid so that arterial PH goes down very little
buffering capacity is dependent on concentration of bicarbonate ions (alkaline reserve)
101
how does the respiratory system make adjustments to pH
Central respiratory centers are most sensitive to CO2 levels
Buildup of CO2 or H+ in blood activates respiratory centers to increase respiratory rate and depth
CO2 is blown off so H+ concentration is reduced
102
if blood PH rises what happens to the respiratory rate
the respiratory rate slows, CO2 accumulates, pushing equation to right so H+ concentration increases and blood PH is restored to normal
103
How do the kidneys influence acid-base balance (PH)
H+ is secreted while HCO3- is reabsorbed
phosphate buffer in filtrate ensures excretion of H+
Glutamine metabolism and NH4+ secretion and excretion
104
Respiratory acidosis
build up of H+ and CO2 retention (hypoventilation)
105
Respiratory Alkalosis
reduce H+, CO2 elimination (hyperventilation)
106
Metabolic acidosis
PH 7.35 (low) HCO3 levels 22 mEQ/L (low)
107
metabolic alkalosis
PH 7.45 (high) HCO3 levels 26 mEq/L (high)
