T23 Renal Urinary Flashcards
1
Q
What are the main functions of the kidney?
A
- maintain the chemical consistency of the blood
- filter liters of fluid from blood
- send toxins, metabolic wastes, and excess water out of body
2
Q
What are the 3 main waste products of the kidney?
A
1) urea
2) uric acid
3) creatine
3
Q
Where are the kidneys located?
A
located retroperitoneally
4
Q
What is the hilum of the kidneys?
A
- on concave surface
- vessels and nerves enter and exit
5
Q
What surrounds the kidney?
A
fibrous capsule
6
Q
What are the 2 parts of the fibroud capsule?
A
- perirenal fat
- renal fascia
7
Q
What are the 3 mechanisms of urine production?
A
1) filtration (glomerular)
2) resorption (tubular)
3) secretion (tubular)
8
Q
What is filtration (production of urine)?
A
liquid filtrate of blood leaves kidney capillaries in glomerular capsule
9
Q
What is resportion (production of urine)?
A
most nutrients, water, and essential ions reclaimed through resorption from urine into peritubular capillaries
10
Q
What is secretion (production of urine)?
A
active process of removing undesirable molecules through secretion from peritubular capillaries into urine
11
Q
What is the nerve plexus that supplies the kidneys?
A
nerve supply to the kidneys via renal plexus
12
Q
What is the renal plexus?
A
- offshoot of celiac plexus
- network of autonomic fibers
- also has sensory fibers
13
Q
What is each nephron composed of?
A
renal corpuscle and renal tubule
14
Q
What is the renal corpuscle?
A
first part of nephron where filtration occurs
15
Q
Where is the renal corpuscle present?
A
present only in kidney cortex
16
Q
What does the renal corpuscle consist of?
A
a tuft of capillaries (glomerulus) that is surrounded by a cup-shaped, hollow glomerular capsule (Bowman’s capsule)
17
Q
What is the tuft of capillaries supplied and drained by?
A
tuft of capillaries supplied by an afferernt arteriole and rained by an efferent arteriole
18
Q
What is the endothelium of the renal corpuscle like?
A
endothelium of glomerulus (tuft of capillaries) is FENESTRATED
19
Q
What does the fenestration of the endothelium of glomerulus allow?
A
makes capillaries highly porous –> allows large quantities of fluid and small molecules to pass from capillaries into capsular space
20
Q
What does the visceral layer of the renal corpuscle cover and consist of?
A
covers glomerulus (glomerular capillaries) and consists of epithelial cells (podocytes) which branch into foot processes
21
Q
Where does filtrate pass through in renal corpuscle?
A
filtration slits (clefts between foot processes)
22
Q
What epithelium is the parietal layer of glomerular capsule?
A
simple squamous epithelium
23
Q
What is the function of the filtration membrane in renal corpuscle?
A
- filter system between blood in glomerulus and capsular space
- holds back most blood cells and proteins
24
Q
What are the 3 layers of the filtration membrane in renal corpuscle?
A
1) fenestrated endothelium of capillary
2) basement membrane
3) thin slit diaphragm
25
What does the filtration membrane in renal corpuscle allow passage of?
-water
-ions
-glucose
-amino acids
-urea
(small and relatively non-polar molecules)
26
What percentage of fluid leaves glomerulus?
20% fluid leaves glomerulus and enters capsular space and processed into urine
27
What percentage of fluid remains within blood of capillary?
80% remains within blood of capillary
28
What are the parts of the renal tubule?
- proximal convoluted tubule
- nephron loop (loop of Henle)
- distal convoluted tubule
- collecting ducts
29
What epithelial cells is on the visceral layer of glomerular capsule?
podocyte
30
What epithelium is in the proximal convoluted tubule in cortex?
simple cuboidal cells with microvilla for efficient resorption
31
What epithelium is in the nephron loop thin segment in medulla?
simple squamous
32
What is the epithelium in the distal convoluted tubule in cortex?
simple cuboidal specialized for selective secretion or resportion of ions
33
What is the epithelium in the collecting ducts?
simple cuboidal that thickens to become simple columnar in papillary ducts
34
What are the 2 classes of nephrons?
- cortical nephrons
| - juxtamedullary nephrons
35
What is the percentage of cortical nephrons?
85%
36
What is the percentage of juxtamedullary nephrons?
15%
37
Where are cortical nephrons located?
located almost entirely within cortex
38
How much do nephron loops dip into the medulla (cortical nephrons)?
dip only a short distance into medulla
39
What is the function of juxtamedullary nephrons?
contribute to kidney's ability to concentrate urine
40
How much do nephron loops dip into the medulla (juxtamedullary nephrons)?
extend deeply into medulla
41
How are the thin segments in loops of juxtamedullary nephrons different from those of cortical nephrons?
thin segments in loops much longer than those of cortical nephrons
42
What is a feature of juxtamedullary nephrons?
have renal corpuscles which lie near cortex-medulla junction
43
What are the 3 capillary beds associated with nephrons?
1) glomeruli capillaries
2) peritubular capillaries of cortical nephrons
3) vasa recta of juxtamedullary nephrons
44
What do the glomeruli capillaries produce?
produce filtrate that moves through the renal tubule and becomes urine
45
What do peritubular capillaries in renal cortex arise from?
arise from efferent arterioles of cortical nephrons
46
Where do peritubular capillaries lie?
in interstitial loose areolar connective tissue in renal cortex
47
What is tubular resorption (in peritubular capillaries?
low-pressure, porous capillaries readily absorb solutes and water from renal tubule cells as these substances are resorbed from filtrate
48
What is tubular secretion (in peritubular capillaries)?
all molecules secretes into urine are from blood of peritubular capillaries
49
What does the vasa recta in renal medulla emerge from?
emerge from efferent arterioles of juxtamedullary nephrons in deepest part of renal cortex
50
How is the vasa recta important for kidney?
important for kidney's urine concentrating mechanism
51
What is the vasa recta in renal medulla?
thin-walled looping vessels which escend into the medulla running alongside the nephron loops
52
How do desert animals conserve their water?
have well developed vasa recta to conserve water
53
When is antidiurectic hormone (vasopressin) released?
released when body needs to conserve water
54
What is antidiurectic hormone produced by and released by?
produced by hypothalamus and released by posterior pituitary gland
55
What does antidiurectic hormone (vasopressin) do?
increases permeability of distal tubules and collecting ducts --> allowing water from filtrate to be resorbed into surrounding blood capillaries which decreases urine volume
56
What is the effect of alcohol on ADH production?
alcohol reduces the production of ADH --> increased urination
57
What is aldosterone?
hormone produced by adrenal cortex that increases resorption of Na+ and water and secretion of K+
58
What does caffeine do to the kidney?
blocks resorption of Na+ from distal covoluted tubules which increases urine production and lowers blood pressure
59
What is the juxtaglomerular apparatus?
- structure that functions in regulating blood pressure
| - area of specialized contact between terminal end of ascending nephron loop and afferent arteriole
60
What are granular cells within the juxtaglomerular apparatus?
- modified smooth muscle cells with secretory granules
| - contain mechanoreceptors and hormone renin
61
What does renin do (granular cells of juxtaglomerular apparatus)?
secreted in response to falling blood pressure in afferent arterioles that triggers renin-angiotensin system which increases aldosterone levels
62
Where is the macula densa (juxtaglomerular apparatus)?
- end of nephron loop
| - adjacent to granular cells
63
What is the macula densa (juxtaglomerular apparatus)?
- tall, closely packed epithelial cells
| - act as chemoreceptors and monitor solute concentration in filtrate
64
What happens to macula densa and granular cells when solute concentrations fall below a certain level?
cells of macula densa signal granular cells to secrete renin
65
What are extraglomerular mesangial cells (juxtaglomerular apparatus)?
interact with macula densa and granular cells to help regulate blood pressure
66
Where are mesangial cells between glomerular capillaries located?
around base of glomerulus
67
What are mesangial cells between glomerular capillaries (juxtaglomerular apparatus)?
cells have contractile properties which help regulate blood flow with glomerulus
68
What is erythropoeitin (hematopoietin)?
glycoprotein hormone that control erythropoiesis by acting as a signaling molecule for erythrocyte precursers in bone marrow
69
What is erythropoeitin (hematopoietin) produced by?
- produced by interstitial fibroblasts in kidney in close association with peritubular capillaries and proximal convoluted tubule
- produced in perisinusoidal cells in liver
70
When is renal production predominant?
adulthood
71
What are the ureters?
carry urine from kidneys to the urinary bladder
72
What is the path of the ureters?
enters in posteriolateral corner of bladder and run medially in bladder wall before opening into bladder's interior
73
What is the mucosa layer of ureter?
transitional epithelium on fibroelastic lamina propria
74
What is the muscularis layer of ureter?
inner longitudinal and outer circular layer of smooth muscle
75
What is the adventitia layer of ureter?
connective tissue
76
What are the 3 layers of urinary bladder?
1) mucosa
2) detrusor muscle (thick muscular layer)
3) fibrous adventitia
77
What does the detrusor muscle do?
contraction of this muscle squeezes urine from bladder during urination
78
What is the trigone?
triangular region in posterior wall of bladder which is defined by openings of the 2 ureters and urethra
79
What is the urinary bladder?
collapsible musclular sac that stores and expels urine
80
Where does an empty bladder lie?
lies entirely within pelvis
81
Where does a full bladder?
expands into lower abdominal cavity and becomes spherical and mucosa rugae flatten out
82
What is the epithelium of the ureters?
transitional epithelium
83
What is the epithelium of the bladder?
transitional epithelium
84
What is the epithelium of the proximal urethra?
transitional epithelium
85
What is the epithelium of the mid-urethra (males)?
stratified and pseudostratified columnar
86
What is the epithelium of the distal urethra?
stratified squamous epithelium
87
Where is the prostate gland in males?
lies directly inferior to bladder and surrounds urethra
88
What are the 3 regions of the male urethra?
1) prostatic urethra - passes through prostate gland
2) membranous urethra - passes through urogenital diaphragm
3) spongy (penile) urethra - passes through length of penis
89
What is the internal urethral sphincter?
involuntary smooth muscle that keeps urethra closed when urine not being passed
90
What is the external urethral sphincter?
- skeletal muscle sphincter inhibits urination until person is ready to urinate
- muscle is voluntarily relaxed which enables urination
91
What is the urogenital diaphragm?
sheet of muscle that surrounds urethra
92
What is micturition?
act of urinating
93
What are the steps of micturition?
1) bladder fills and stretch receptors send messages
2) micturition response initiated
3) contraction of detrusor muscle and opening of internal urethral sphincter
4) sympathetic efferents to bladder inhibited
5) somatic motor efferent to external urethral sphincter inhibited --> voluntary muscle and pee
94
What is urinary tract infection?
- common in females
| - burning sensation during micturition
95
What is renal calculi?
kidney stones
96
What gender is bladder cancer more common in?
more common in men
97
What is kidney cancer?
arises from epithelial cells of urine tubules
98
How are kidneys and bladder affected by age?
- nephrons decrease in size and number
- tubules less efficient at secretion and reabsorption
- filtration declines
- recognition of desire to urinate delayed
- loss of muscle tone in bladder
