Urinary System Chapt. 24 Flashcards
1
Q
Urinary system
A
(organs of excretion) composed of a pair of kidneys and urinary tract
2
Q
Kidneys what do they do?
A
filter blood to remove metabolic waste products
3
Q
Kidney fluid is modify resulting fluid for following purposes:
A
Fluid, electrolyte, Acid-base, and blood pressure homeostasis
4
Q
Urinary tract is composed of?
A
a pair of ureters, urinary bladder, and a single
urethra
5
Q
The follow of Urine
A
Urine exits kidneys through ureters found on posterior body wall
Each ureter empties into urinary bladder on floor of pelvic cavity where urine is stored
Urine exits from urinary bladder through Urethra; allows urine to exit body
6
Q
Kidneys are site where urinary system regulates homeostatic processes: (7 function)
A
🔸️Filter blood to remove metabolic wastes
🔸️Regulate fluid and electrolyte balance
🔸️Regulate blood PH
🔸️Influence blood pressure
🔸️Releasing hormone erythropoietin (EPO)
🔸️Detoxifying substances in blood
🔸️Vitamin D (calcitriol-absorption ca)
7
Q
Kidneys structure and location
A
Kidneys look like beans in both shape and color
Both kidneys are found outside and posterior to peritoneal membrane (retroperitoneal)
Right kidney is found in a slightly inferior position due to liver
Left kidney is positioned between T12-L3 using vertebral column as reference
8
Q
Protection for kidneys
A
11th and 12th ribs provide some protection for both kidneys
9
Q
Adrenal gland
(Location & component of what system?)
A
component of endocrine system; found on superior pole of each kidney
10
Q
Kidneys Three external layers of CT from deep to superficial:
A
- Renal capsule
- Adipose capsule
- Renal fascia
11
Q
Kindneys 3 external layers of CT: Renal capsule
A
thin layer of dense irregular connective tissue; covers
exterior of each kidney
12
Q
Kindneys 3 external layers of CT: Adipose capsule
A
protects from physical trauma
13
Q
Kindneys 3 external layers of CT: Renal fascia
A
dense irregular CT;
anchors each kidney to peritoneum and musculature of posterior abdominal wall
14
Q
Hilum
A
opening on medial surface of kidney where renal artery, vein, nerves, and ureters enter and exit
15
Q
What makes up urine-forming portion of kidney?
A
Renal cortex and the renal medulla
16
Q
Renal cortex
A
90-95% of all kidney’s blood vessels are found in renal cortex
17
Q
Renal columns
A
extensions of renal cortex;
pass through renal medulla toward renal pelvis
18
Q
Over one million nephrons are found within…
A
Renal cortex and Renal medulla of each kidney
19
Q
Renal corpuscle found in…
A
renal cortex
20
Q
Renal tubule found mostly in…
A
Renal cortex with some tubules dipping into Renal medulla
21
Q
Cone-shaped renal pyramids are found within
A
renal medulla separated by renal columns on either side
22
Q
Each renal pyramid tapers into a slender papilla followed by
A
minor calyx
major calyx
renal pelvis
ureter
23
Q
What type of muscle is within walls of the calyces and renal pelvis that contract and propel urine towards ureter?
A
Smooth muscle tissue
24
Q
Nephrons have 2 structures that are?
A
Renal corpuscle and Renal tubule
25
renal arteries are branches of?
abdominal aorta
26
Blood flow through the kidneys
(13 steps)
1- renal artery
2-segmental artery
3- interlobar artery
4- Arcuate Artery
5- interlobular (cortical radiate artery)
6-afferent arteriole
7-glomerulus
8- efferent arteriole
9-peritubular capillaries
10- interlobular veins
11- arcuate veins
12- interlobar vein
13- renal vein
27
Kidney contains unusual capillary bed system where
arterioles both feed and drain capillaries; normally function of a venule
28
glomerulus
1st capillary bed
1st Part of filtration takes place
29
peritubular capillaries
2nd capillary bed,
(Around the tubules)
30
Venous blood exits kidney
parallel to arterial pathway
31
Renal vein exits the kidneys from what opening and drains into what vien?
exits kidney from hilum to drain into inferior vena cava
32
Nephron are considered a?
Functional unit of the kidneys
33
What does the Renal corpuscle do?
-filters blood
34
Glomerulus is a group of
looping fenestrated capillaries coverd by podocytes
35
Glomerular capsule (Bowman's capsule) consists of...
outer parietal layer (simple squamous epithelium) & inner visceral layer (podocytes)
36
Glomerular capsule (Bowman's capsule) is made out of what cells?
lined with simple squamous epithlial cells
37
Capsular space is a...
hollow region between parietal (glomerular capsule) and visceral layers (Glomerulus)
38
Renal corpuscle is made of?
Glomerulus (inside)
Glomerular capsule (the outside)
39
Renal tubule: Proximal tubule (pct)
-Reabsorption and Secretion
Large quantity of ions, sodium, potassium, chloride, sulfate, and phosphate; vital to electrolyte homeostasis
Almost 100% of nutrients including glucose, amino acids, water-soluble vitamins, and lactic acid
40
Renal tubule: Nephron loop
(descending limb, ascending limb)
Dips into Renal medulla (reabsorption)
41
Distal tubule (dct)
Reabsorption & Secretion
42
Juxtaglomerular apparatus (JGA)
composed of both macula densa and juxtaglomerular (JG) cells
43
Macula densa
Is a group of cells in contact with modified smooth muscle cells (juxtaglomerular (JG) cells)
44
JGA regulates...
blood pressure (BP) and glomerular filtration rate (GFR)
45
when BP too low, JG cells release...
Renin
RAAS activated->
->increased BP
46
Collecting system is made of?
both medullary collecting duct (cd) and papillary duct that further modify filtrate before it exits kidney
47
cortical cd leads too
medullary cd→
papillary duct
48
Once filtrate enters papillary duct it is known as
urine
49
Urine exits papillary duct at papilla of renal pyramid into a
minor calyx
50
Cortical nephrons
Cortical nephrons make up about 80% of nephrons in kidneys
Renal corpuscles are found in outer renal cortex; have short nephron loops that barely enter renal medulla
51
Juxtamedullary nephrons
- much less common than cortical nephrons
Renal corpuscles are found near boundary between renal cortex and medulla; have long nephron loops that travel deep within renal medulla
52
Glomerular filtration
🔸️Selectively based on size so Cells and Large proteins are not filtered and remain in the circulating blood
🔸️Smaller substances exit blood to enter capsular space as filtrate
Filtration
🔸️Glomerulus-> BowMan's Capsule
53
TUBULAR REABSORPTION
Reabsorbing substances such as water, glucose, amino acids, and electrolytes from tubular fluid to return them into circulating blood
Reabsorption Tubules -> Blood
54
TUBULAR SECRETION
Substances are added into filtrate from peritubular capillaries
Helps maintain electrolyte and acid-base homeostasis; removes toxins from blood that did not enter tubular fluid by filtration
Secretion Blood -> Tubules
55
Fenestrated glomerular capillary: Fenestrations
are large pores
Water and small dissolved solutes pass through filtration membrane easily
56
Fenestrated glomerular capillary: Nitrogenous wastes
group of small substances that are readily filtered; include:
o Urea and ammonium ions (NH4+) from protein metabolism
оCreatinine-waste product of muscle metabolism
оUric acid-product of nucleic acid metabolism
57
GLOMERULAR FILTRATION RATE
(Definition)
The amount of filtrate formed by both kidneys in one minute is known as glomerular filtration rate (GFR); 125 ml/min (180 liters / day )
58
Net filtration pressure at glomerulus is determined by three driving forces:
1. Glomerular hydrostatic pressure (GHP)
2. Glomerular colloid osmotic pressure (GCOP)
3. Capsular hydrostatic pressure (CHP)
59
1. Glomerular hydrostatic pressure (GHP)-
blood pressure; higher than average capillary bed hydrostatic pressure
60
2. Glomerular colloid osmotic pressure (GCOP)
-created mostly by albumin; pulls water back into glomerular capillaries
61
3. Capsular hydrostatic pressure (CHP)-
generated as capsular space rapidly fills with new filtrate (10 mm Hg) as fluid can only move so quickly into renal tubule which opposes filtration
62
Net filtration pressure (NFP) is combination of these three forces (formula)
NFP=GHP- (GCOP + CHP)
10 = 50 - (30 + 10)
NFP favors filtration as GHP is greater than sum of forces that oppose filtration (GCOP+CHP)
63
Autoregulation -
internal kidney mechanisms that work to maintain Glomerular Filtration Rate (GFR)
64
Myogenic
mechanism constriction of smooth muscle in blood vessel walls in response to increases in BP
65
Tubuloglomerular feedback -
uses macula densa of distal renal tubule to control pressure in glomerulus in response to NaCl concentration of filtrate
66
(RAAS)
What does it stand for n what does it maintain?
Renin-angiotensin-aldosterone system
🔸️complex system that maintains systemic BP
67
Atrial natriuretic peptide (ANP)
- hormone released by heart cells in atria in response to increasing fluid volume; lowers blood volume and BP to reduce workload of the heart
ANP increases GFR by dilating afferent arterioles and constricting efferent arterioles; increases glomerular hydrostatic pressure
68
Neural regulation of GFR primarily involves...
Sympathetic divison of ANS
69
renal failure
GFR decreases, kidneys may be unable to carry out their vital functions
70
Renal failure may be a short-term condition known as...
acute renal failure or acute kidney injury
71
Uremia
-condition that can develop when GFR is less than 50% of normal; leads to buildup of waste products, fluid, electrolytes, as well as acid- base imbalances, all of which can lead to coma, seizures, and death if untreated
72
Dialysis
can be used to treat the signs and symptoms of uremia
73
tubular reabsorption flow is
substances pass from filtrate into interstitial fluid then into peritubular capillaries to re-enter blood
74
Tubular secretion pathway
substances move from blood into interstitial fluid then
into tubule with filtrate
Secretion is an active process
75
Facultative water reabsorption
- water is reabsorbed based on body's needs
76
Aldosterone comes from where and what does it do?
-from adrenal cortex;
increases reabsorption of sodium ions from filtrate and secretion of potassium ions into filtrate
77
Antidiuretic Hormone (ADH)
Comes from where and is secreted for what? And what does it do?
From hypothalamus and secreted by posterior pituitary; causes water reabsorption; reduces urine output
78
Atrial natriuretic peptide (ANP) stimulates what? And inhibits what 2 hormones?
stimulates urinary excretion of sodium ions while it also inhibits release of both aldosterone and ADH
79
Medullary collecting system
last chance for regulation of fluid before filtrate becomes urine
80
Kidneys produce dilute urine when?
solute concentration of extracellular fluid is too low
81
What 3 things can cause urine to be dilute?
-Less ADH [Antidiuretic Hormone]
-Distal tubule and collecting duct become impermeable to water
- More water, less solutes in blood
82
Kidneys effectively conserve water by producing very concentrated urine using two mechanisms:
🔸️Release of ADH [Antidiuretic Hormone]
🔸️Countercurrent mechanism
83
Countercurrent mechanism
creates and maintains osmotic gradient by exchanging materials in opposite directions between filtrate and interstitial fluids
84
Countercurrent multiplier proceeds in following steps:
🔸️NaCl is actively transported from ascending limb filtrate into interstitial fluid
🔸️Hypertonic fluid then pulls water out of filtrate in descending limb into
interstitial fluid
85
URINE COMPOSITION & URINALYSIS
(9 things)
🔸️water [H20]
🔸️Sodium [Na]
🔸️Potassium [K]
🔸️Chloride (Cl)
🔸️Hydrogen ion [H]
🔸️Phosphates
🔸️Sulfates
🔸️Metabolic wastes such as urea, creatinine, ammonia, and uric acid
🔸️Small amounts of bicarbonate (NaHCO3), calcium (Ca), and magnesium (Mg) may be present
86
Urine color
What gives urine its color, and what is it called? And what does darker or lighter urine mean?
🔸️Urochrome; breakdown product of hemoglobin
🔸️Darker urine is more concentrated; has less water
🔸️Lighter urine is less concentrated; has more water
87
Urine color should be...
Translucent
88
Urine smell, what oder should it have and what does it mean if strong odor is present?
Mild odor; strong odor may be caused by diseases, infections, or by ingesting certain foods
89
Urine pH and weight
Normal pH (6.0); ranges from 4.5-8.0
Specific gravity 1.001 (very dilute) to 1.035 (very concentrated)
90
Renal clearance:
Measurement of rate at which kidneys remove a substance from blood
For a substance to provide an accurate measure of renal clearance and GFR, substance should be completely filtered and neither reabsorbed nor secreted
91
Renal clearance: Creatinine
not totally accurate
(5-50% in urine arrived via secretion, not filtration)
92
Renal clearance: inulin
More accurate assessment of GFR can be obtained using inulin; neither secreted or absorbed; must be injected
93
ANATOMY OF THE URINARY TRACT
Urinary tract consists of two ureters, urinary bladder, and urethra
94
Ureter is how long and empties into?
Ureter is 25-30 cm long and empties into urinary bladder
95
Layers of the Ureters from superficial to deep
1. Adventitia
2. Mascularis
3. Mucosa
96
Layers of the Ureters: Adventitia
most superficial layer; made of fibrous connective tissue
97
Layers of the Ureters: Mascularis
middle layer; made of smooth muscle cells that contract rhythmically (peristalsis) to propel urine toward urinary bladder
98
Layers of the Ureters: Mucosa
deepest layer; mucous membrane composed of transitional epithelium
99
Urinary bladder
hollow, distensible organ found on pelvic cavity floor
100
Urinary bladder shape is called
Trigone
101
Urinary bladder: Trigone
triangular region on bladder floor; openings of two ureters
are found at each posterior corner
102
Urinary bladder: Bladder wall tissue from superficial to deep
1. Adventitia
2. Detrusor muscle
3. Mucosa
103
Urinary bladder: Bladder wall tissue: Adventitia
most superficial layer; made of areolar connective tissue
104
Urinary bladder: Bladder wall tissue: Detrusor muscle
middle layer; squeeze bladder; (internal urethral sphincter) is found at opening of urethra (all made of smooth muscle)
105
Urinary bladder: Bladder wall tissue: Mucosa
innermost layer; made of transitional epithelium
106
Urethra
-drains urine from urinary bladder to outside of body; walls are similar to ureters
107
Urethra: An external urethral sphincter is formed by
levator ani muscle
108
Urethra: levator ani muscle is made out of what muscle?
skeletal muscle of pelvic floor; allows for voluntary control of urination
109
Female urethra
How long is it?
What is the opening called?
about four cm in length; opens at external urethral orifice between vagina and clitoris
110
Male urethra
How long?
How many regions?
about 20 cm, consists of three regions
111
Male urethra 3 regions
1. Prostatic urethra
2. Membranous urethra
3. Spongy (penile) urethra
112
Another word of Urination is?
Micturition; discharge of urine from urinary bladder to outside of body
113
Micturition reflex
Reflex arc mediated by parasympathetic nervous system when urine fills bladder and stretches walls
114
Micturition reflex:
Stretch receptors send signal...
Send a signal to sacral region of the spinal cord via sensory afferent fibers
115
Micturition reflex: Parasympathetic
efferent fibers stimulate detrusor muscle to contract and internal urethral sphincter to relax; allows for micturition
116
Micturition center is found?
Found in pons (CNS); given time and training makes micturition a voluntary process
