A&P 25: The Urinary System Flashcards
1
Q
Urinary System
A
system including the kidneys, ureters, urinary bladder, and urethra
2
Q
Renal hilum
A
vertical cleft in the medial surface of the kidney
3
Q
Renal fascia
A
outer layer of dense fibrous connective tissue that anchors the kidney and the adrenal gland to surrounding structures
4
Q
Perirenal fat capsule
A
fatty mass that surrounds the kidney and cushions it against blows
5
Q
Fibrous capsule
A
transparent capsule that prevents infections in surrounding regions from spreading to the kidney
6
Q
Renal cortex
A
most superficial region of the kidney; light-colored, granular appearance
7
Q
Renal medulla
A
deep to the cortex of the kidney; dark, reddish-brown; exhibits cone-shaped tissue masses
8
Q
Medullary/renal pyramids
A
cone-shaped tissue masses in the renal medulla
9
Q
Renal columns
A
inward extensions of cortical tissue separating the medullary/renal pyramids
10
Q
Lobes
A
each pyramid and its surrounding cortical tissue constitutes 1 of 8 of these sections of the kidney
11
Q
Renal pelvis
A
funnel-shaped tube continuous with the ureter leaving the hilum
12
Q
Major calyces
A
branching extensions of the pelvis form 2 or 3 of these
13
Q
Minor calyces
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each major calyces subdivides to form several of these cup-shaped areas that enclose the papillae
14
Q
Renal arteries
A
large arteries of the kidney; deliver 1/4 of the total cardiac output to the kidneys each minute
15
Q
Segmental arteries
A
as each renal artery approaches a kidney, it divides into 5 of these arteries
16
Q
Interlobar arteries
A
within the renal sinus, each segmental artery branches further for form several of these arteries
17
Q
Arcuate arteries
A
at the cortex-medulla junction, the interlobar arteries branch into these arteriers that arch over the bases of the medullary pyramids
18
Q
Cortical radiate arteries
A
AKA interlobular arteries; small arteries that radiate outward from the arcuate arteries to supply the cortical tissue
19
Q
Cortical radiate, arcuate, interlobar, renal veins
A
veins that trace the pathway of the arterial supply in reverse (except there are no segmental veins)
20
Q
Renal plexus
A
variable network of autonomic nerve fibers and ganglia; provides the nerve supply of the kidney and its ureter; offshoot of the celiac plexus
21
Q
Nephrons
A
structural and functional units of the kidneys; each kidney contains over 1 million of these tiny blood-processing units, which carry out the processes the form urine
22
Q
Renal corpuscle
A
each of these structures consist of a tuft of capillaries (glomerulus)
23
Q
Glomerulus
A
tuft of capillaries; “ball of yarn”
24
Q
Glomerular capsule
A
cup-shaped hollow structure that makes up the renal corpuscle along with the glomerulus; AKA Bowman’s capsule
25
Filtrate
plasma-derived fluid; raw material that the renal tubules process to form urine
26
Podocytes
"foot cells"; highly modified, branching epithelial cells that make up the visceral layer of glomerular capsule
27
Foot processes
octopus-like podocytes terminate in these, which interdigitate as they cling to the basement membrane of the glomerulus
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Filtration slits
the clefts/openings between the foot processes
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Capsular space
filtrate enters this space through the filtration slits inside the glomerular capsule
30
Renal tubule
3cm (1.2 in) long; 3 major parts; leaves the glomerular capsule at the proximal convoluted tubule, drops into the nephron loop, then winds/twists again as the distal convoluted tubule before emptying into a collecting duct
31
Proximal convoluted tubule
walls of this tube are formed by cuboidal epithelial cells with large mitochondria; apical (luminal) surfaces bear dense microvilli
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Nephron loop
U-shaped loom (formerly called the loop of Henle)
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Descending nephron limb
descending loop of Henle
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Ascending nephron limb
ascending loop of Henle
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Distal convoluted tubule
walls of this tubule are cuboidal; thinner; almost entirely lack microvilli
36
Collecting duct
2 cell types in this duct - principal cells (with sparse, short microvilli; responsible for maintaining they body's water and Na+ balance) & intercalated cells (cuboidal cells with abundant microvilli; 2 types, A & B; maintain acid-base balance of the blood)
37
Cortical nephrons
85% of the nephrons in the kidneys
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Juxtamedullary nephrons
originate close to the cortex-medulla junction; play an important role in the kidneys' ability to produce concentrated urine
39
Afferent/efferent arteriole
arterioles that feed/drain the glomerulus
40
Peritubular capillaries
capillaries that cling closely to adjacent renal tubules and empty into nearby venules; arise from the high-resistance efferent arterioles so only experience low pressure; readily absorb solutes and water from the tubule cells as these substances are reclaimed from the filtrate
41
Vasa recta
bundles of long straight vessels formed from efferent arterioles serving the juxtamedullary nephrons
42
Juxtaglomerular complex (JGC)
each nephronhas this region where the most distal portion of the ascending limb of the nephron loop lies against the afferent arteriole feeding the glomerulus
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Macula densa
group of tall, closely packed cells in the ascending limb of the nephron loop that lies adjacent to the granular cells
44
Granular cells
AKA juxtaclomerular (JG) cells; in the arteriolar walls; = enlarged smooth muscle cells with prominent secretory granules containing the enzyme renin; act as mechanoreceptors that sense the BP in the afferent arteriole
45
Urine
fluid containing unneeded substances such as excess salts and metabolic wastes
46
Glomerular filatration
passive process in which hydrostatic pressure forces fluids and solutes through a membrane
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Filtration membrane
porous membrane lying between the blood and the interior of the glomerular capsule; allows free passage of water and solutes smaller than plasma proteins
48
Hydrostatic pressure in glomerular capillaries (HPgc)
glomerular blood pressure; chief force pushing water and solutes out of the blood and across the filtration membrane
49
Hydrostatic pressure in the capsule space (HPcs)
pressure exerted by filtrate in the glomerular capsule; much higher than hydrostatic pressure surrounding most capillaries because filtrate is confined in a small space with a narrow outlet
50
Colloid Osmotic pressure in glomerular capillaries (OPgc)
pressure exerted by proteins in the blood
51
Net filtration pressure (NFP)
HPgc, HPcs, and OPgc determine this pressure; largely determines glomerular filtration rate
52
Glomerular filtration rate (GFR)
volume of filtrate formed each minute by the combined activity of all 2 million glomeruli of the kidneys
53
Renal autoregulation
the kidneys adjusting its own resistance to blood flow; how the kidneys can maintain a nearly constant GFR despite fluctuations in systemic arterial BP
54
Myogenic mechanism
reflects a property of vascular smooth muscle (contracts when stretched and relaxes when not stretched)
55
Tubuloglomerular feedback mechanism
autoregulation by this flow-dependent mechanism is directed by the macula densa cells of the juxtaglomerular complex
56
Renin-angiotensin-aldosterone mechanism
body's main mechanism for increasing BP
57
Renin
low BP causes the granular cells of the juxtaglomerular complex to release this enzyme by one+ pathways
58
Tubular reabsorption
reclaims most of the tubule contents and returns them to the blood; selective transepithelial process that begins as soon as the filtrate enters the proximal tubules
59
Active tubular reabsorption
process requiring ATP either directly (primary active transport) or indirectly (secondary active transport)
60
Passive tubular reasborption
diffusion, facilitated diffusion, and osmosis (substances moving down electrochemical gradients)
61
Aquaporins
transmembrane proteins that aid the passive tubular reabsorption of water by acting as water channels across cell membranes
62
Obligatory water reabsorption
water flow that obliges the body to absorb water in the proximal nephron regardless of its state of over- or underhydration
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Facultatiive water reabsorption
water reabsorption that depends on ADH
64
Transport maximum (Tm)
max for substances that are reabsorbed using a transport protein in the membrane; reflects the number of transport proteins in the renal tubules available to ferry a particular substance (in mg/min)
65
Tubular secretion
reabsorption in reverse; way to clear plasma of unwanted substances is not to reabsorb them from the filtrate; moves selected substances (H+, K+, NH4+, creatinine, and certain organic acids/bases) from the peritubular capillaries through the tubule cells into the filtrate
66
Countercurrent multiplier
interaction between the flow of filtrate through the ascending and descending limbs of the long nephron loops of juxtamedullary nephrons
67
Countercurrent exchanger
flow of blood through the ascending and descending portions of the vasa recta
68
Medullary osmotic gradient
osmotic gradient that allows the kidneys to vary urine concentration dramatically
69
Diuretics
chemicals that enhance urinary output
70
Renal clearance
volume of plasma from which the kidneys clear (completely remove) a particular substance in a given time, usually 1 minute; C=UV/P where U is the concentration of the substance in the urine (mg/mL), V = flow rate of urine formation (mL/min) and P = concentration of the substance in the plasma (mg/mL)
71
Chronic renal disease
GFR less than 60mL/min for at least 3 months
72
Renal failure
GFR less than 15mL/min; filtrate formation decreases or stops completely
73
Uremia
clinical syndrome associated with renal failure; "urine in the blood"; includes fatigue, anorexia, nausea, mental changes, and muscle cramps
74
Hemodialysis
procedure using an artificial kidney apparatus, passing the patient's blood through a membrane tubing that is permeable only to selected substances; the tubing is immersed in a solution that differs slightly from normal cleansed plasma; retains/adds needed substances, removes wastes, excess ions
75
Urochrome
yellow color of urine is due to this pigment that results when they body destroys hemoglobin
76
Specific gravity
ratio of the mass of a substance to the mass of an equal volume of distilled water
77
Urea
largest component of urine by weight, apart from water; derived from the normal breakdown of amino acids
78
Nitrogenous wastes
metabolic wastes
79
Uric acid
end product of nucleic acid metabolism
80
Creatinine
metabolite of creatine phosphate, which is found in large amounts in skeletal muscle tissue where it stores energy to regenerate ATP
81
Ureters
slender tubes that convey urine from the kidneys to the bladder
82
Renal calculi
kidney stones
83
Urinary bladder
smooth, collapsible, muscular sac that stores urine temporarily
84
Trigone
smooth, triangular region of the bladder base outlined by the openings of the ureters and the urethra; infections tend to persist in this region
85
Detrusor
muscular layer of the bladder; consists of intermingled smooth muscle fibers in inner and outer longitudinal layers and a middle circular layer
86
Urethra
thin-walled muscular tube that drains urine away from the bladder and conveys it out of the body
87
Internal urethral sphincter
at the bladder-urethra junction, the detrusor smooth muscle thickens to form this involuntary sphincter
88
External urethral sphincter
voluntary sphincter surrounding the urethra as it passes through the urogenital diaphragm
89
External urethral orifice
external opening of the urethra
90
Prostatic urethra
in males, the portion of the urethra running within the prostate
91
Intermediate part of the urethra
AKA membranous urethra; runs through the urogenital diaphragm; extends about 2cm from the prostate to the beginning of the penis
92
Spongy urethra
15cm long; passes through the penis and opens at its tip via the external urethral orifice
93
Micturition
urination; voiding; act of emptying the bladder
94
Incontinence
after the toddler years, this is usually a result of weakened pelvic muscles following childbirth or surgery, physical pressure during pregnancy, or nervous system problems
95
Urinary retention
condition in which the bladder is unable to expel its contained urine; common after general anesthesia
96
Catheter
slender drainage tube inserted into the urethra to drain urine and prevent bladder trauma from excessive stretching
97
Pronephros
1st tubule system that forms during the 4th week of development
98
Pronephric duct
connects the pronephros (gone by the 6th week) to the cloaca; persists and is used by the later-developing kidneys
99
Mesonephros
2nd renal system; claims the pronephric duct; comes to be called the mesonephric duct
100
Metanephros
when the mesonephric kidneys degenerate, this 3rd set makes its appearance
101
Ureteric buds
hollow structures that push superiorly from the mesonephric duct into the urogenital ridge
102
Ureteric ducts
the distal ends of the ureteric buds form the renal pelves, calyces, and collecting ducts & their unexpanded proximal parts, now called this, become the ureters
103
Urogenital sinus
as the metanephros is developing, the cloaca subdivides to form the future rectum and anal canal & this, into which the urinary and genital ducts empty
