URINARY SYSTEM Flashcards
1
Q
Organs of the Urinary system
A
• Kidneys
• Ureters
• Urinary bladder
• Urethra
2
Q
Functions of the Urinary System
A
• Elimination of waste products (nitrogenous waste, toxins and drugs)
• Regulate aspects of
homeostasis (water balance, electrolytes, acid-based balance, blood pressure, RBC production and activation of vit. D)
3
Q
• Retroperitoneal bean-shaped organ in superior lumbar region
• Extends from vertebral levels T12 superiorly and L3 inferiorly
• Coverings: (from innermost to outermost)
• Renal capsule
• Perirenal fat
• Renal fascia
A
kidneys
4
Q
Regions of the kidney
A
renal cortex, medulla, and pelvis
5
Q
outer region
A
renal cortex
6
Q
inside the cortex
A
renal medulla
7
Q
inner collecting tube
A
Renal pelvis
8
Q
Kidney Structures
A
Medullary pyramids, Renal columns and calyces
9
Q
triangular regions of tissue in the medulla
A
Medullary pyramids
10
Q
extensions of cortex-like
material inward
A
Renal columns
11
Q
cup-shaped structures that funnel
urine towards the renal pelvis
A
calyces
12
Q
• Functional units of kidney
• 1-1.5 million
A
nephron
13
Q
2 types of nephron
A
Cortical and Juxtamedullary
14
Q
➢Removal of waste and reabsorption of
nutrients
A
cortical (85%)
15
Q
Concentration
of urine
A
Juxtamedullary
16
Q
Parts of Nephron
A
Glomerulus
Renal Tubule
17
Q
a high-pressure tuft of capillaries with openings
• Attached to
arterioles on both sides
• Large afferent arteriole
• Narrow efferent arteriole
A
Glomerulus
18
Q
• Bowman’s capsule
• Proximal Convoluted Tubule (PCT)
• Loop of Henle
• Distal Convoluted Tubule (DCT)
A
Renal Tubule
19
Q
Layers of Bowman’s capsule
A
Outer parietal layer and Inner visceral layer
20
Q
composed of simple
squamous epithelium
A
Outer parietal layer
21
Q
composed of branching
podocytes which cling to the glomerulus
A
Inner visceral layer
22
Q
• Arise from efferent arteriole of the glomerulus
• Cling close to the renal tubule
• Reabsorb some substances from collecting tubes
A
Peritubular Capillaries
23
Q
glomerulus plus the Bowman’s
capsule
A
Renal / Malphigian Corpuscles
24
Q
consists of juxtaglomerular cells of the
afferent arteriole and the macula densa of the DCT
A
Juxtaglomerular apparatus
25
Mechanism of Urine Formation
1. Glomerular filtration
2. Tubular reabsorption
3. Tubular secretion
26
• Involves passing the blood through layers of filtration barrier which
includes:
• Glomerular endothelial cell
• Basement membrane
• Epithelial cells of Bowman’s capsule
• Nonselective passive process
• Filtrate is collected in the glomerular capsule and leaves via the
renal tubule
Glomerular Filtration
27
Factors Affecting Filtration Process
1. Cellular structure of the capillaries and the
Bowman’s capsule
2. Glomerular Pressure
3. Renin-angiotensin-aldosterone system
28
3 types of Glomerular Filtration
Glomerular hydrostatic pressure
Glomerular osmotic pressure
Capsular hydrostatic pressure
29
Chief force pushing water and solute across the filtration membrane
Glomerular hydrostatic pressure
30
Opposes filtration
Glomerular osmotic pressure
31
Opposes filtration; force exerted by the fluid in the Bowman’s capsule
Capsular hydrostatic pressure
32
Force responsible for filtrate formation
NFP = glomerular hydrostatic pressure – (osmotic + capsular hydrostatic)
Net Filtration Pressure (NFP)
33
Concerned with conservation of solutes
• Reabsorption Mechanism:
• Active Transport
• Passive Transport
• Gradients
Tubular Reabsorption
34
• Controls the concentration process
• Production is determined by the state of body hydration.
↑Body Hydration = ↓ADH = ↑Urine Volume
↓Body Hydration = ↑ADH = ↓Urine Volume
Vasopressin/ADH
35
• the passage of substances from the blood in the peritubular capillaries to
the tubular filtrate
• two major functions:
✓Elimination of waste products not filtered by the glomerulus
✓Regulation of the acid-base balance in the body through the secretion of
hydrogen ions
Tubular Secretion
36
• 25-30cm slender muscular tube that conveys urine, through peristalsis, from the
kidneys to the urinary bladder
• Runs behind the peritoneum
• Anatomical constrictions of the Ureter where stones can be arrested
• Ureteropelvic junction
• Bifurcation of common iliac vessels near the pelvic brim
• Vesico-ureteral junction
ureter
37
• A smooth, distensible muscular sac, lying posterior to the pubic
symphysis
• Storage of urine
• Trigone – three openings
• Two from the ureters
• One to the urethra
Urinary bladder
38
• Three layers of smooth muscle (detrusor muscle)
• Mucosa made of transitional epithelium
• Walls are thick and folded in an empty bladder
• Bladder can expand significantly without increasing internal
pressure
Urinary Bladder Wall
39
• Thin-walled muscular tube draining urine from the urinary bladder to
the body exterior
• Release of urine is controlled by two sphincters
• Internal urethral sphincter (involuntary)
• External urethral sphincter (voluntary)
Urethra
40
Length
• Females – 3–4 cm (1 inch)
• Males – 20 cm (8 inches)
• Location
• Females – along wall of the vagina
• Males – through the prostate and penis
Urethra Gender Differences
true
41
• A process of emptying the bladder
• Both sphincter muscles must open to allow voiding
• The internal urethral sphincter is relaxed after stretching of the bladder
• Activation is from an impulse sent to the spinal cord and then back via the pelvic
splanchnic nerves
• The external urethral sphincter must be voluntarily relaxed
Micturition (Urination)
42
Renal Function Tests
CLEARANCE TESTS
Specimen:
1. Urea clearance
2. Creatinine clearance
3. Inulin clearance
4. β2-microglobulin
5. Radioisotopes
Glomerular Filtration Tests
43
• Requirements:
• 24-hour urine
• Serum
• Unit: ml/min
• C= UV/P
V (ml/min) = ml (actual collected sample)
no. minutes (collection)
Glomerular Filtration Tests
44
1. Specific Gravity
2. Mosenthal Concentration Test
3. Fishberg Concentration Test
4. Osmolarity
Tubular Reabsorption Tests
45
Tubular Secretion and Renal Blood Flow Tests
Titratable Acidity and Urinary Ammonia
p-aminohippuric acid (PAH)
46
✓use a substance that is completely removed from the blood
✓Disadvantage →
✓ Exogenous
p-aminohippuric acid (PAH)
47
• H+
• NH3
• cells of DCT
• NV: approx 70 mEq/day
• Alkaline tides (diurnal variation):
• Post prandial → 2pm / 8pm
• Lowest pH: night
Titratable Acidity and Urinary Ammonia
48
Kidneys are unable to do its physiologic functions such as concentrating urine,
removal of wastes and maintaining electrolytes and pH balance of the body
• Causes: drugs, toxic chemicals, infections, hypertension, DM., etc.
renal failure
49
• Normal amount of water in the human body
• Young adult females – 50%
• Young adult males – 60%
• Babies – 75%
• Old age – 45%
• Water is necessary for many body functions
and levels must be maintained
Maintaining Water Balance
50
in Distribution of Body Fluid • Intracellular fluid (inside cells)
• Extracellular fluid (outside cells)
• Interstitial fluid
• Blood plasma
true
51
2 types of Fluid Exchange
Hydrostatic pressure and Osmotic pressure
52
pressure which tends to push fluid out of the
intravascular component
Hydrostatic pressure
53
pressure exerted by the solutes which tend to attract water
Osmotic pressure
54
• Changes in electrolyte balance causes water to move from one
compartment to another
• Alters blood volume and blood pressure
• Can impair the activity of cells
The Link Between Water and Salt
55
in Maintaining Water Balance • Water intake must equal water output
• Sources for water intake
• Ingested foods and fluids
• Water produced from metabolic processes
• Sources for water output
• Vaporization out of the lungs
• Lost in perspiration
• Leaves the body in the feces
• Urine production
true
56
Disorders of water balance
Dehydration, Edema
57
• Occurs when water loss exceeds water intake
• Manifested as thirst, dry skin and decreased urine output
Dehydration
58
Abnormal accumulation of fluid in the interstitial space
• May be secondary to increased hydrostatic pressure or decreased in osmotic pressure or
lymphatic obstruction
Edema
59
Regulation is primarily by hormones
• Antidiuretic hormone (ADH) prevents excessive water loss in urine
• Aldosterone regulates sodium ion content of extracellular fluid
true
60
Released by cells in the atria of heart to increase BP
Atrial Natriuretic Factor
61
Cells in the kidneys and hypothalamus are active monitors
true
62
due to its chemical similarity with aldosterone (increases Na
reabsorption)
estogen
63
blocks the effect of aldosterone
Progesterone
64
exhibit aldosterone-like effect
Glucocorticoids
65
Blood pH must remain between 7.35 and 7.45 to maintain
homeostasis
• Alkalosis – pH above 7.45
• Acidosis – pH below 7.35
true
66
Most ions originate as byproducts of cellular metabolism
true
67
single or paired sets of molecules that
resists shifts in pH by releasing or binding H+
Chemical buffer system
68
eliminates volatile acids
• Acidosis activates the respiratory center to increase respiratory rate and depth
which eliminates CO2 and causes pH to rise.
• Alkalosis depresses respiratory center, resulting in CO2 retention and a fall in
pH
Respiratory center in the brain stem
69
eliminates metabolic or fixed acids
• Major long-term mechanism for controlling acid-base balance
• Acts mainly by excreting H+ and conserving bicarbonates
renal mechanisms
70
Abnormalities of Acid-Base Balance
Respiratory acidosis, Respiratory alkalosis, Metabolic acidosis, Metabolic alkalosis
71
decreased pH resulting from CO2 retention
Respiratory acidosis
72
increased pH resulting from rapid elimination of CO2
Respiratory alkalosis
73
Metabolic acidosis
decreased pH resulting from accumulation of metabolic
acids or rapid loss of bicarbonates in the urine
74
increased pH resulting from excessive bicarbonates in the
blood or loss of acids
Metabolic alkalosis
