EXCRETORY SYSTEM Flashcards
1
Q
MULTIPLE FUNCTIONS OF THE KIDNEYS
Primary function:
A
Waste Removal
Fluid and Electrolyte Balance
filter blood plasma
2
Q
MULTIPLE FUNCTIONS OF THE KIDNEYS
Primary function:
Waste Removal - remove waste from the body via ______
A
urine
3
Q
MULTIPLE FUNCTIONS OF THE KIDNEYS
Primary function:
Fluid and Electrolyte Balance - homeostatic function of regulating ______ and ______
A
body fluid volume, electrolyte composition
4
Q
MULTIPLE FUNCTIONS OF THE KIDNEYS
Primary function:
Kidneys filter ______ by removing unwanted substances but essential substances are returned to the ______, while waste is excreted in ______.
A
blood plasma, blood, urine
5
Q
MULTIPLE FUNCTIONS OF THE KIDNEYS
Key Homeostatic Roles of the Kidneys:
A
- Excretion of metabolic waste products and foreign chemicals
- Regulation of water and electrolyte balances
- Regulation of body fluid osmolality and electrolyte concentrations
- Regulation of arterial pressure
- Regulation of acid-base balance
- Regulation of erythrocyte production
- Secretion, metabolism, and excretion of hormones
- Gluconeogenesis
6
Q
MULTIPLE FUNCTIONS OF THE KIDNEYS
Key Homeostatic Roles of the Kidneys
- Excretion of metabolic waste products and foreign chemicals
______ are the primary means by which the body eliminates metabolic waste products that the body no longer needs.
Waste products:
> ______ - from amino acid metabolism
> ______ -from muscles
> ______ - from nucleic acid breakdown
> ______ - ex. bilirubin.
> ______
Additionally, kidneys remove ______ and ______ (e.g., pesticides, drugs, food additives.
These waste and toxins are removed as ______ as they are produced.
A
Kidneys
Urea
Creatinine
Uric Acid
Hemoglobin Breakdown Products
Metabolites of Hormones
toxins, foreign substances
quickly
7
Q
MULTIPLE FUNCTIONS OF THE KIDNEYS
Key Homeostatic Roles of the Kidneys
- Regulation of Water and Electrolyte Balances
Excretion of water and electrolytes must ______ intake to maintain homeostasis.
______ Leads to an increase in the body’s substance levels.
______ Leads to a decrease in the body’s substance levels.
How kidney maintains homeostasis:
- Adjust ______ rates based on intake, which is influenced by eating and drinking habits.
- After a sudden increase in sodium intake, kidneys adapt in ______-______ days to restore balance between intake and excretion.
- Temporary sodium buildup triggers ______, increasing ______.
A
match
Excess Intake
Deficient Intake
excretion
2, 3
hormonal responses, sodium excretion
8
Q
MULTIPLE FUNCTIONS OF THE KIDNEYS
Key Homeostatic Roles of the Kidneys
- Regulation of body fluid osmolality and electrolyte concentrations
- Sodium intake raised from ______ to ______ mEq/day.
- Kidneys adjust to excrete ______ mEq/day within ______-______ days.
- The kidney can handle sodium intake from ______ mEq/day to ______ mEq/day with minimal changes to extracellular fluid volume or plasma sodium
- This adaptability extends to other electrolytes like ______, ______, ______, and more.
A
30, 300
300, 2, 3
10, 1500
chloride, potassium, calcium
9
Q
MULTIPLE FUNCTIONS OF THE KIDNEYS
Key Homeostatic Roles of the Kidneys
- Regulation of Arterial Pressure
______ Regulation: Adjust arterial pressure by varying sodium and water excretion.
______ Regulation: Secrete hormones and vasoactive substances (e.g., renin) to produce vasoactive compounds like angiotensin II, which affect blood vessel constriction and pressure.
A
Long-Term
Short-Term
10
Q
MULTIPLE FUNCTIONS OF THE KIDNEYS
Key Homeostatic Roles of the Kidneys
- Regulation of Acid-Base Balance
- Work with ______ and body fluid ______ to regulate acid-base balance.
- ______: Eliminate specific metabolic acids, like sulfuric and phosphoric acids, which result from protein metabolism.
- ______: Adjust body fluid buffer stores to maintain pH balance.
A
lungs, buffers
Acid Excretion
Buffer Regulation
11
Q
MULTIPLE FUNCTIONS OF THE KIDNEYS
Key Homeostatic Roles of the Kidneys
- Regulation of Erythrocyte Production
Erythropoietin Secretion: Kidneys secrete ______ to stimulate ______ production in the ______.
Trigger: ______ (low oxygen levels) prompts increased erythropoietin secretion.
Impact of Kidney Disease: Severe kidney disease or removal can lead to ______ due to reduced erythropoietin production.
A
erythropoietin, red blood cell, bone marrow
Hypoxia
anemia
12
Q
MULTIPLE FUNCTIONS OF THE KIDNEYS
Key Homeostatic Roles of the Kidneys
- Secretion, metabolism, and excretion of hormones
The kidneys convert vitamin D into its active form, ______ (______), by hydroxylating it at the “number ______” position.
- Essential for calcium ______ in bones.
- Promotes calcium ______ from the gastrointestinal tract.
- Helps regulate both ______ and ______ levels in the body, contributing to bone health and mineral balance.
A
1,25-dihydroxyvitamin D3, calcitriol, 1, deposition, absorption, calcium, phosphate
13
Q
MULTIPLE FUNCTIONS OF THE KIDNEYS
Key Homeostatic Roles of the Kidneys
- Gluconeogenesis / Glucose Synthesis
During prolonged fasting, kidneys perform ______, creating glucose from amino acids and other precursors.
Homeostatic Disruption: Chronic kidney disease or acute kidney failure disrupts ______ and ______ balance.
Accumulation of Toxins: Without functioning ______, potassium, acids, and fluids build up rapidly, leading to severe health issues.
Risk of Death: Complete renal failure can be fatal within days if not treated with interventions like ______, which helps restore fluid and electrolyte balance.
A
gluconeogenesis
fluid, electrolyte
kidneys
hemodialysis
14
Q
PHYSIOLOGICAL ANATOMY OF THE KIDNEYS
General Organization
______ - Each one weighs about 150 g and is fist-sized.
A
KIDNEY
15
Q
PHYSIOLOGICAL ANATOMY OF THE KIDNEYS
General Organization
______ - Enclosed by a fibrous capsule for protection
A
CAPSULE OF KIDNEY
16
Q
PHYSIOLOGICAL ANATOMY OF THE KIDNEYS
General Organization
______ - Area where renal artery, vein, lymphatics, nerves, and ureter pass.
A
HILUM
17
Q
PHYSIOLOGICAL ANATOMY OF THE KIDNEYS
General Organization
______ - Transports urine to the bladder.
A
URETER
18
Q
PHYSIOLOGICAL ANATOMY OF THE KIDNEYS
General Organization
______ - Project into the renal pelvis, leading to the ureter.
A
PAPILLAE
19
Q
PHYSIOLOGICAL ANATOMY OF THE KIDNEYS
General Organization
______ - Collect urine from renal tubules.
A
MAJOR AND MINOR CALYCES
20
Q
PHYSIOLOGICAL ANATOMY OF THE KIDNEYS
General Organization
Urine is propelled by contractile elements in the walls of ______, ______, and ______ toward the bladder for storage
A
calyces, pelvis, ureter
21
Q
PHYSIOLOGICAL ANATOMY OF THE KIDNEYS
General Organization
INTERNAL ANATOMY:
______ - outer
A
CORTEX
22
Q
PHYSIOLOGICAL ANATOMY OF THE KIDNEYS
General Organization
INTERNAL ANATOMY:
______ - inner; has 8-10 renal pyramids; each pyramid ends in the papilla
A
MEDULLA
23
Q
PHYSIOLOGICAL ANATOMY OF THE KIDNEYS
Renal Blood Supply
Renal artery enters through the ______, branching into ______, ______, ______ (______) arteries, and then ______.
A
hilum, interlobar, arcuate, interlobular, radial, afferent arterioles
24
Q
PHYSIOLOGICAL ANATOMY OF THE KIDNEYS
Renal Blood Supply
Two capillary beds in series: ______ (for filtration, high pressure) and ______ (for reabsorption, low pressure), separated by ______.
A
glomerular, peritubular, efferent arterioles
25
PHYSIOLOGICAL ANATOMY OF THE KIDNEYS
Renal Blood Supply
Afferent and efferent arterioles adjust resistance to control ______ in capillaries, affecting ______ and ______ rates.
hydrostatic pressure, glomerular filtration, tubular reabsorption
26
PHYSIOLOGICAL ANATOMY OF THE KIDNEYS
Renal Blood Supply
Blood from peritubular capillaries enters venous vessels: ______ vein, ______ vein, ______ vein, and finally ______ vein, exiting the kidney
interlobular, arcuate, interlobar, renal
27
PHYSIOLOGICAL ANATOMY OF THE KIDNEYS
Nephron - Functional Unit of the Kidney
Each kidney has ______ to ______ nephrons, responsible for urine formation.
800,000, 1,000,000
28
PHYSIOLOGICAL ANATOMY OF THE KIDNEYS
Nephron - Functional Unit of the Kidney
Nephrons cannot be ______; they ______ with aging, injury, or disease.
replaced, decrease
29
PHYSIOLOGICAL ANATOMY OF THE KIDNEYS
Nephron - Functional Unit of the Kidney
By age ______, many have ______% fewer nephrons than at age ______, though the remaining nephrons adapt to maintain function.
80, 40, 40
30
PHYSIOLOGICAL ANATOMY OF THE KIDNEYS
Nephron - Functional Unit of the Kidney
Structure of Nephron:
______: Network of capillaries with high pressure for filtering blood; enclosed in ______.
Glomerulus, Bowman’s capsule
31
PHYSIOLOGICAL ANATOMY OF THE KIDNEYS
Nephron - Functional Unit of the Kidney
Structure of Nephron:
______: Converts filtered fluid into urine.
Renal Tubule
32
PHYSIOLOGICAL ANATOMY OF THE KIDNEYS
Nephron - Functional Unit of the Kidney
Pathway of Filtered Fluid:
Filters at the ______ > flows into ______ > ______ (in cortex) > ______ > ______ (in cortex) > ______ > ______ > ______ > ______ (becomes the medullary collecting duct) > ______
Glomerular Capillaries, Bowman’s Capsule, Proximal Tubule, loop of Henle, distal tubule, connecting tubule, cortical collecting tubule, cortical collecting duct, renal medulla, renal papillae
33
PHYSIOLOGICAL ANATOMY OF THE KIDNEYS
Nephron - Functional Unit of the Kidney
Pathway of Filtered Fluid:
Loop of Henle - contains a ______ (thin) and ______ (lower end is thin). Thin parts of the loop are called ______ and the rest of the ascending limb is called the ______
descending, ascending limb, thin segment of the loop of Henle, thick segment of the loop of Henle
34
PHYSIOLOGICAL ANATOMY OF THE KIDNEYS
Nephron - Functional Unit of the Kidney
______ - inside the end of thick ascending limb contains this specialized epithelial tissue
Macula Densa
35
MICROTURITION / URINATION PROCESS
Involves two main steps:
1. Bladder Filling
2. Micturition Reflex
36
MICROTURITION / URINATION PROCESS
Involves two main steps:
______: Bladder fills until wall tension reaches a threshold.
Bladder Filling
37
MICROTURITION / URINATION PROCESS
Involves two main steps:
______: A nervous reflex triggered by increased tension, causing bladder emptying or a desire to urinate. This is a spinal cord reflex “______”. This can be inhibited or enhanced by the cerebral cortex or brain stem.
Micturition Reflex, Autonomic Spinal Reflex
38
Physiologic Anatomy of the Bladder
______: Main part where urine collects.
Body
39
Physiologic Anatomy of the Bladder
______: Funnel-shaped, connects to the urethra
Neck / Posterior Urethra
40
Physiologic Anatomy of the Bladder
______: Smooth triangular area on the posterior bladder wall, where ureters enter at upper angles, and bladder neck opens into posterior urethra.
Trigone
41
Physiologic Anatomy of the Bladder
______: Smooth muscle that makes up bladder walls; contracts to increase bladder pressure. Muscle cells are interconnected, allowing a unified contraction (action potential) to empty the bladder.
Detrusor Muscle
42
Physiologic Anatomy of the Bladder
______: Found in the bladder neck, composed of detrusor muscle and elastic tissue. Prevents urine leakage by maintaining natural tone until bladder pressure rises to the threshold.
Internal Sphincter
43
Physiologic Anatomy of the Bladder
______: Located in the urogenital diaphragm, beyond the posterior urethra. Composed of voluntary skeletal muscle, allowing conscious control to prevent urination even when involuntary signals prompt bladder emptying.
External Sphincter
44
MICROTURITION / URINATION PROCESS
Transport of Urine from the Kidney Through the Ureters and Into the Bladder
No major changes in urine composition occur after it leaves the collecting ducts and travels through the ______, ______, and into the ______.
renal calyces, ureters, bladder
45
MICROTURITION / URINATION PROCESS
Transport of Urine from the Kidney Through the Ureters and Into the Bladder
______ and ______ Activity: Urine flow stretches the ______, initiating ______ that move urine from the renal pelvis down the ureter.
Calyces, Pacemaker, calyces, peristaltic contractions
46
MICROTURITION / URINATION PROCESS
Transport of Urine from the Kidney Through the Ureters and Into the Bladder
The ureter walls contain ______ innervated by ______, ______ nerves and an ______.
smooth muscle, sympathetic, parasympathetic, internal nerve plexus
47
MICROTURITION / URINATION PROCESS
Transport of Urine from the Kidney Through the Ureters and Into the Bladder
______: Inhibited by sympathetic stimulation and enhanced by parasympathetics
Peristalsis
48
MICROTURITION / URINATION PROCESS
Transport of Urine from the Kidney Through the Ureters and Into the Bladder
Ureters enter the bladder through the ______ in the ______, with the ______ compressing the ureters to prevent ______ (______) during contraction.
detrusor muscle, trigone, detrusor muscle, urine backflow, reflux
49
MICROTURITION / URINATION PROCESS
Transport of Urine from the Kidney Through the Ureters and Into the Bladder
______: Ureter does not travel far enough through the bladder wall, causing urine to flow back into the ureter. This can lead to ureter enlargement and potential damage to renal structures if severe.
Vesicoureteral Reflux
50
Pain Sensation in the Ureters and the Ureterorenal Reflex
Ureters are well-supplied with ______ nerves. A blocked ureter, such as by a ______, triggers intense reflex constriction and severe pain.
pain, stone
51
Pain Sensation in the Ureters and the Ureterorenal Reflex
Pain impulses initiate a ______ that constricts renal ______, reducing ______.
sympathetic reflex, arterioles, urine output
52
Pain Sensation in the Ureters and the Ureterorenal Reflex
______: This reflex helps prevent excessive fluid buildup in the kidney pelvis by decreasing urine flow from the affected kidney when a ureter is blocked.
Ureterorenal Reflex
53
MICROTURITION / URINATION PROCESS
The kidneys regulate the excretion of substances in the urine through three key processes:
1. Glomerular Filtration
2. Tubular Reabsorption
3. Tubular Secretion
54
MICROTURITION / URINATION PROCESS
The kidneys regulate the excretion of substances in the urine through three key processes:
______: Blood flows through the glomerular capillaries, where a large amount of plasma, nearly free of protein, is filtered into Bowman’s capsule.
Glomerular Filtration
55
MICROTURITION / URINATION PROCESS
The kidneys regulate the excretion of substances in the urine through three key processes:
______: After filtration, the filtered fluid travels through the renal tubules, where specific solutes and water are reabsorbed back into the blood.
Tubular Reabsorption
56
MICROTURITION / URINATION PROCESS
The kidneys regulate the excretion of substances in the urine through three key processes:
______: Some substances are actively transported from the blood in the peritubular capillaries into the renal tubules. This enhances the excretion of certain waste products and toxins.
Tubular Secretion
57
Overall Urinary Excretion Rate (UER):
Filtration rate − Reabsorption rate + Secretion rate = UER
58
MICROTURITION / URINATION PROCESS
Renal Handling of Substances:
1. No Reabsorption or Secretion
2. Partial Reabsorption
3. Complete Reabsorption
4. Secretion in Addition to Filtration
59
MICROTURITION / URINATION PROCESS
Renal Handling of Substances:
______: Certain waste products like ______ are filtered and excreted without reabsorption or secretion, making their excretion rate ______ to the filtration rate.
No Reabsorption or Secretion, creatinine, equal
60
MICROTURITION / URINATION PROCESS
Renal Handling of Substances:
______: Substances like ______ and ______ ions are filtered, then partly reabsorbed, so the excretion rate is ______ than the filtration rate.
Partial Reabsorption, sodium, chloride, less
61
MICROTURITION / URINATION PROCESS
Renal Handling of Substances:
______: Nutrients such as ______ and ______ are completely reabsorbed from the tubules, ______ their excretion and ______ them.
Complete Reabsorption, glucose, amino acids, preventing, conserving
62
MICROTURITION / URINATION PROCESS
Renal Handling of Substances:
______: ______ and ______ are not only filtered but also actively secreted, which results in a ______ excretion rate, aiding in the efficient removal of these substances from the body.
Secretion in Addition to Filtration, Organic acids, bases, high
63
______—THE FIRST STEP IN URINE FORMATION
GLOMERULAR FILTRATION
64
______ is the function of the glomerulus
Filtration
65
______ and ______ are the functions of tubular portion of nephron
Reabsorption, secretion
66
______ is the first process of urine formation, “The process by which the blood that passes through glomerular capillaries is filtered through the filtration membrane”.
Glomerular Filtration
67
FILTRATION MEMBRANE
Formed by three layers:
1. Glomerular Capillary Membrane
2. Basement membrane
3. Visceral Layer of Bowman’s Capsule
68
FILTRATION MEMBRANE
Formed by three layers:
Glomerular Capillary Membrane
- Single layer of ______ cells.
endothelial
69
FILTRATION MEMBRANE
Formed by three layers:
Glomerular Capillary Membrane
- It has many pores called ______ or ______.
Fenestra, Filteration pores
70
FILTRATION MEMBRANE
Formed by three layers:
Glomerular Capillary Membrane
- Diameter of about ______ micron.
0.1
71
FILTRATION MEMBRANE
Formed by three layers:
Glomerular Capillary Membrane
- Surrounding the endothelium is the ______.
basement membrane
72
FILTRATION MEMBRANE
Formed by three layers:
Basement membrane
- Forms the separation between the ______ endothelium and the epithelium of ______.
glomerular capillary, visceral layer of Bowman's capsule
73
FILTRATION MEMBRANE
Formed by three layers:
Visceral Layer of Bowman’s Capsule
- Single layer of flattened ______ cells resting on ______.
epithelial, basement membrane
74
FILTRATION MEMBRANE
Formed by three layers:
Visceral Layer of Bowman’s Capsule
- Cells are connected with ______ by cytoplasmic processes called ______ or ______.
basement membrane, Pedicles, Feet
75
FILTRATION MEMBRANE
Formed by three layers:
Visceral Layer of Bowman’s Capsule
- Arrangment of pedicles are ______ manner leaving small cleft like spaces in between called ______
interdigitating, Slit Pores
76
FILTRATION MEMBRANE
Formed by three layers:
Visceral Layer of Bowman’s Capsule
- The epithelial cells with pedicles are called ______.
Podocytes
77
FILTRATION MEMBRANE
Formed by three layers:
These three layers make up ______ that prevents filtration of ______.
filtration barrier, plasma proteins
78
GLOMERULAR (BOWMAN’S CAPSULE)
Bowman's capsule surrounds glomerulus forming
capsular space
Two layers of capsule:
Visceral layer
Parietal layer
79
GLOMERULAR (BOWMAN’S CAPSULE)
Bowman's capsule surrounds glomerulus forming
capsular space
Two layers of capsule:
______ layer - Podocytes (foot cells) modified simple squamous
Visceral
80
GLOMERULAR (BOWMAN’S CAPSULE)
Bowman's capsule surrounds glomerulus forming
capsular space
Two layers of capsule:
______ layer - Simple squamous epithelium Think of it as a fist punched into an inflated bag
Parietal
81
PROCESS OF GLOMERULAR FILTRATION:
1. Blood enters glomerular capillary
2. Filters out of renal corpuscle
82
PROCESS OF GLOMERULAR FILTRATION:
Filters out of renal corpuscle
- ______ and ______ stay behind
- Everything else is filtered into ______
- The filtered fluid is called ______.
Large proteins, cells
nephron
glomerular filtrate
83
Glomerular filtration is called ______ because even the ______ are filtered. But the ______ are not filtered due to their larger molecular size.
Ultrafiltration, minute particles, plasma proteins
84
The glomerular filtrate contains all the substances present in plasma except the ______.
plasma proteins
85
GLOMERULAR FILTRATION RATE (GFR):
GFR = Kf x (PG - PB - piG + piB)
86
______: “The rate at which plasma is filtered into Bowman's capsule.”
GLOMERULAR FILTRATION RATE (GFR)
87
GLOMERULAR FILTRATION RATE (GFR)
The units of filtration are a ______ filtered per ______, e.g. m/min or liters/day.
volume, unit time
88
GLOMERULAR FILTRATION RATE (GFR)
______% of filtrate is reabsorbed, ______ to ______L is excreted as urine.
99, 1, 2
89
FILTRATION FRACTION:
Filtration fraction = GFR/Renal plasma flow
90
______: “Fraction of the renal plasma which becomes the filtrate."
FILTRATION FRACTION
91
______: It is the ratio between glomerular filtration rate and renal plasma flow.
FILTRATION FRACTION
92
FILTRATION FRACTION
It is expressed in Percentage between ______%-______%.
15, 20
93
FILTRATION FRACTION
GFR is about ______ ml/min, or ______ L/day, which means that about ______% of the plasma flowing through the kidney is filtered through the glomerular capillaries
125, 180, 20
94
FACTORS AFFECTING GFR:
1. Renal Blood Flow
2. Tubuloglomerular Feedback
3. Glomerular Capillary Pressure
4. Colloidal Osmotic Pressure
5. Hydrostatic Pressure in Bowman's Capsule
6. Constriction of Afferent Arterioles
7. Constriction of Efferent Arterioles
8. Systemic Arterial Pressure
9. Sympathetic Stimulation
10. Surface Area of Capillary Membrane
11. Permeability of Capillary Membrane
12. Contraction of Glomerular Mesangial Cells
13. Hormonal factors
14. Angiotensin II
95
Norepinephrine
Effect on GFR:
down
96
Epinephrine
Effect on GFR:
down
97
Endothelin
Effect on GFR:
down
98
Angiotensin II
Effect on GFR:
mantains, prevents down
99
Endothelial-derived nitric oxide
Effect on GFR:
up
100
Prostaglandins
Effect on GFR:
up
101
FACTORS AFFECTING GFR
INCREASE GFR:
Increased renal blood flow
Increased glomerular pressure
Increased BP
Efferent arteriolar constriction
High Protein Intake
High Glucose Intake
102
FACTORS AFFECTING GFR
DECREASE GFR:
Increased plasma colloid osmotic pressure
Increased Bowman's capsule pressure
Afferent arteriolar constriction
Sympathetic stimulation causing afferent arteriolar constriction
103
RENAL BLOOD FLOW
- In a 70-kg man, kidney blood flow is around ______ ml/min, about ______% of cardiac output.
- Despite making up only ______% of body weight, kidneys receive significantly high blood flow.
- This high blood flow ensures enough plasma for ______, crucial for fluid and solute regulation.
1100, 22
0.4
glomerular filtration
104
CHARACTERISTICS OF THE RENAL BLOOD FLOW:
1. High blood flow
2. Two capillary beds
105
CHARACTERISTICS OF THE RENAL BLOOD FLOW:
High blood flow
______ ml/min, or ______ percent of the cardiac output. ______% to the cortex.
1100, 22, 94
106
CHARACTERISTICS OF THE RENAL BLOOD FLOW:
Two capillary beds
High hydrostatic pressure in ______ (about ______ mmHg) and low hydrostatic pressure in ______ (about ______ mmHg)
glomerular capillary, 60, peritubular capillaries, 13
107
BLOOD FLOW IN VASA RECTA
Blood flow to renal medulla is supplied by ______.
vasa recta
108
BLOOD FLOW IN VASA RECTA
Blood flow in vasa recta of medulla is very ______ as compared to blood flow in cortex.
low
109
BLOOD FLOW IN VASA RECTA
Blood flow in renal medulla is ______-______ % of total renal blood flow.
1, 2
110
BLOOD FLOW IN VASA RECTA
Vasa recta are important to form ______ urine.
concentrated
111
RENAL BLOOD FLOW AND OXYGEN CONSUMPTION
On a per gram weight basis, the kidneys normally consume oxygen at ______ the rate of the brain but have almost ______ times the blood flow of the brain.
twice, seven
112
RENAL BLOOD FLOW AND OXYGEN CONSUMPTION
A large part of 02 consumed by kidneys is related to high rate of active ______ by ______.
sodium ions re-absorption, renal tubules
113
RENAL BLOOD FLOW AND OXYGEN CONSUMPTION
If renal blood flow & GFR ______, ______ sodium ions is filtered and absorbed, consuming ______ 02.
decreases, less, less
114
RENAL BLOOD FLOW AND OXYGEN CONSUMPTION
Renal 02 consumption is ______ related to renal tubular sodium ions re-absorption.
directly
115
DETERMINANTS OF RENAL BLOOD FLOW: (formula)
RBF = (Renal artery pressure - Renal vein pressure)/Total renal vascular resistance
116
MEASUREMENT OF RENAL BLOOD FLOW
The blood flow to kidney is measured by using ______ of ______.
plasma clearance, para-aminohippuric acid
117
REGULATION OF RENAL BLOOD FLOW
The renal blood flow is regulated by means of ______.
auto regulation
118
REGULATION OF RENAL BLOOD FLOW
Two mechanisms are involved in renal auto regulation:
1. Myogenic response
2. Tubuloglomerular feedback
119
REGULATION OF RENAL BLOOD FLOW
Two mechanisms are involved in renal auto regulation:
Tubuloglomerular feedback
______ plays an important role in tubuloglomerular feedback which controls the renal blood flow and GFR. It acts as a sensor in detecting conc. of ______ in ______ and accordingly alters ______ and ______.
Macula densa, NaCl, tubular fluid, glom. blood flow, GFR
120
MYOGENIC RESPONSE:
1. The blood flow to kidney increases
2. Stretches the elastic wall of afferent arteriole
3. It increases the flow of calcium ions from ECF in to the cells
4. Influx leads to the contraction of smooth muscles in afferent arteriole
5. Causes constriction & increases in resistance in afferent arteriole
6. Blood flow is controlled
121
TUBULOGLOMERULAR FEEDBACK:
1. Increase in GFR
2. Increase in NaCl concentration
3. in renal tubule
4. Macula Densa releases
5. Adenosine from ATP
6. Constriction of afferent arteriole
7. Decreases in Glomerular blood flow
8. Decreases in GFR
9. Decrease in GFR
10. Decrease in NaCl concentration
11. in renal tubule
12. Macula Densa releases
13. Prostaglandin E2, Bradykinin, Renin
14. Dilatation of afferent arteriole
15. Increases in Glomerular blood flow
16. Increases in GFR
122
Filtration, Reabsorption, and Secretion of Different Substances
In general, ______ is quantitatively more important than ______ in the formation of ______, but ______ plays an important role in determining the amounts of ______ and ______ ions and a few other substances that are excreted in the urine.
tubular reabsorption, tubular secretion, urine, secretion, potassium, hydrogen
123
Filtration, Reabsorption, and Secretion of Different Substances
Certain foreign substances and drugs are also poorly reabsorbed but, in addition, are secreted from the blood into the ______, so their excretion rates are ______.
tubules, high
124
Filtration, Reabsorption, and Secretion of Different Substances
______, such as ______ ions, ______ ions, and ______ ions, are ______ reabsorbed, so only small amounts appear in the urine.
electrolytes, sodium, chloride, bicarbonate, highly
125
Filtration, Reabsorption, and Secretion of Different Substances
Each of the processeslomerular filtration tuular reabsorption, and tubular secretion—is regulated according to the ______ of the body
changes in glomerular filtration and tubular reabsorption usually act in a ______ manner to produce the necessary changes in ______
needs, coordinated, renal excretion
126
______ can move a solute against an electro-chemical gradient and requires energy derived from metabolism. Transport that is coupled directly to an energy source, such as the hydrolysis of ______, is termed ______
Active transport, adenosine triphosphate (ATP), primary active transport
127
Although solutes can be reabsorbed by ______ and/ or ______ mechanisms by the tubule, water is always reabsorbed by a ______ (______) physical mechanisms called ______, which means water diffusion from a region of low solute concentration (high water concentration) to one of high solute concentration (low water concentration)
active, passive, passive, nonactive, osmosis
128
Regulation of Tubular Reabsorption
Because it is essential to maintain a precise balance between ______ and ______, there are multiple nervous, hormonal, and local control mechanisms that regulate tubular reabsorption, just as there are for control of glomerular filtration. An important feature of tubular reabsorption is that reabsorption of some solutes can be regulated ______ of others, especially through ______ control mechanismst
tubular reabsorption, glomerular filtration, independently, hormonal
129
Reabsorption and Secretion Along Different Parts of the Nephron
Normally, about ______ percent of the filtered load of ______ and ______ and a slightly lower percentage of filtered ______ are reabsorbed by the ______ before the filtrate reaches the ______.
65, sodium, water, chloride, proximal tubule, loops of Henle
130
Reabsorption and Secretion Along Different Parts of the Nephron
The ______ segment of the ______ of the ______ empties into the ______. The first portion of the ______ forms the ______, a group of closely packed epithelial cells that is part of the juxtaglo-merular complex and provides feedback control of GFR and blood flow in this same nephron
thick, ascending limb, loop of Henle, distal tubule, distal tubule, macula densa
131
Reabsorption and Secretion Along Different Parts of the Nephron
The ______ of the ______ and the subsequent ______ have similar functional characteristics. Anatomically, they are composed of two distinct cell types, the ______ cells and ______ cells. The ______ cells reabsorb sodium and water from the lumen and secrete potassium ions into the lumen. The ______ cells reabsorb potassium ions and secrete hydrogen ions into the tubular lumen
second half, distal tubule, cortical collecting tubule, principal, intercalated, principal, intercalated
132
KIDNEYS EXCRETE EXCESS WATER BY FORMING ______ URINE
DILUTE
133
KIDNEYS EXCRETE EXCESS WATER BY FORMING DILUTE URINE
Normal kidneys can adjust urine ______ to manage body fluid levels. When there’s excess water, they can produce ______ urine with an osmolarity as low as ______ mOsm/L. Conversely, during water deficit, they can ______ urine up to ______-______ mOsm/L.
composition, dilute, 50, concentrate, 1200, 1400
134
KIDNEYS EXCRETE EXCESS WATER BY FORMING DILUTE URINE
ANTIDIURETIC HORMONE CONTROLS URINE ______
CONCENTRATION
135
KIDNEYS EXCRETE EXCESS WATER BY FORMING DILUTE URINE
A primary effector of this feedback is ______, also called ______. When body fluid osmolarity ______, the posterior pituitary secretes more ______, enhancing water ______ in the kidneys and reducing urine ______ without significantly affecting ______. Conversely, when there’s excess water and lower osmolarity, ______ secretion decreases, leading to more ______ urine. Thus, the level of ______ largely determines whether urine is ______ or ______.
antidiuretic hormone (ADH), vasopressin, increases, ADH, reabsorption, volume, solute excretion, ADH, dilute, ADH, concentrated, dilute
136
KIDNEYS EXCRETE EXCESS WATER BY FORMING DILUTE URINE
RENAL MECHANISMS FOR EXCRETING DILUTE URINE
After consuming 1 liter of water, urine volume can increase to ______ times within ______ minutes. The urine osmolarity decreases from ______ to around ______ mOsm/L, allowing the kidneys to eliminate excess water without losing significant solutes.
six, 45, 600, 100
137
KIDNEYS EXCRETE EXCESS WATER BY FORMING DILUTE URINE
Tubular Fluid Remains ______ in Proximal Tubules
- As fluid flows through the proximal tubule, solutes and water are reabsorbed in ______ proportions, so little change in osmolarity occurs. Thus, the proximal tubule fluid remains ______ to the plasma.
Isosmotic, equal, isosmotic
138
KIDNEYS EXCRETE EXCESS WATER BY FORMING DILUTE URINE
Tubular Fluid Is ______ in the Ascending Loop of Henle
- In the ______ of the ______, sodium, potassium, and chloride are actively ______, while the segment remains ______, even with high ______. This makes the tubular fluid progressively ______, reducing its osmolarity to about ______ mOsm/L by the early ______. Thus, fluid exiting this segment is ______, about ______ that of plasma, regardless of ADH levels.
Diluted, thick ascending limb, loop of Henle, reabsorbed, water-impermeable, ADH, dilute, 100, distal tubule, hypo-osmotic, one-third
139
KIDNEYS EXCRETE EXCESS WATER BY FORMING DILUTE URINE
Tubular Fluid in Distal and Collecting Tubules Is Further ______ in Absence of ______
- As fluid moves from the early distal tubule to the late distal tubule and collecting ducts, additional sodium chloride is reabsorbed. Without ______, these segments remain ______, diluting the tubular fluid to as low as ______ mOsm/L, resulting in a large volume of dilute urine due to solute reabsorption and minimal water reabsorption.
Diluted, ADH, ADH, water-impermeable, 50
140
KIDNEYS CONSERVE WATER BY EXCRETING ______ URINE
CONCENTRATED
141
______ Function: Essential for forming concentrated urine, essential for the survival of land mammals, including humans.
Kidney
142
Water Loss: Continuous loss occurs via:
______ (evaporation into the expired air)
______ (feces)
______ (evaporation and perspiration)
______ (urine excretion)
Lungs
Gastrointestinal tract
Skin
Kidneys
143
______ Intake: Must match water loss, but the ability of the kidneys to form a small volume of concentrated urine ______ the fluid intake required to maintain ______, an important function when water is in short supply.
Fluid, minimizes, homeostasis
144
Water Deficit Response:
- Kidneys excrete ______ while increasing ______.
- Decreases ______, forming ______.
solutes, water reabsorption, urine volume, concentrated urine
145
Maximal Concentration: Human kidneys can achieve a urine concentration of ______ to ______ mOsm/L (______-______ times plasma osmolarity).
1200, 1400, 4, 5
146
Calculation of the obligatory urine volume:
600 mOsm/day / 1200 mOsm/L = 0.5 L/day
147
______
- Provides a rapid estimate of urine solute concentration.
Urine Specific Gravity
148
Urine Specific Gravity
- Increases with urine ______ and typically increases ______ with ______.
concentration, linearly, osmolarity
149
______
- Reflects the weight of solutes in a given urine volume.
Urine Specific Gravity
150
Urine Specific Gravity
- Normal range in humans: ______ to ______ g/ml.
1.002, 1.028
151
Urine Specific Gravity
- ______ offer approximate measurements; laboratories usually use ______ for accuracy.
Dipsticks, refractometers
152
Basic requirements for forming a concentrated urine:
- high level of ADH
- high osmolarity of the renal medullary interstitial fluid
153
Basic requirements for forming a concentrated urine:
a ______, increases the permeability of distal tubules and collecting ducts to water, enhancing water reabsorption
high level of ADH
154
Basic requirements for forming a concentrated urine:
a ______, which provides the osmotic gradient necessary for water reabsorption to occur in the presence of high levels of ADH.
high osmolarity of the renal medullary interstitial fluid
155
The renal medullary interstitium around the collecting ducts is typically ______. High ______ levels allow water to osmotically move into the interstitium, where it is carried away by the ______. Thus, urine concentration depends on ______ levels and the renal medulla's ______, which is established by the ______.
hyperosmotic, ADH, vasa recta, ADH, hyperosmolarity, countercurrent multiplier mechanism
156
The ______ depends on the special anatomical arrangement of the loops of Henle and vasa recta, the specialized peritubular capillaries of the renal medulla.
countercurrent multiplier mechanism
157
COUNTERCURRENT MULTIPLIER MECHANISM PRODUCES ______ RENAL MEDULLARY INTERSTITIUM
HYPEROSMOTIC
158
COUNTERCURRENT MULTIPLIER MECHANISM PRODUCES HYPEROSMOTIC RENAL MEDULLARY INTERSTITIUM
The osmolarity of interstitial fluid is about ______ mOsm/L in most body parts, but in the kidney medulla, it can rise to ______ to ______ mOsm/L in the pelvic tip of the medulla. . This means that the renal medullary interstitium has accumulated solutes in great excess of water. A high concentration of solutes is maintained by a balanced inflow and outflow of solutes and water in the medulla.
300, 1200, 1400
159
Major factors that contribute to the buildup of solute concentration into the renal medulla:
- Active transport of sodium and co-transport of potassium, chloride, and other ions from the thick ascending limb of the loop of Henle into the medullary interstitium
- Active transport of ions from the collecting ducts into the medullary interstitium
- Facilitated diffusion of urea from the inner medullary collecting ducts into the medullary interstitium
- Small amounts of water diffuse from the medullary tubules into the interstitium, much less than solute reabsorption.
160
LOOP OF HENLE CHARACTERISTICS THAT CAUSE SOLUTES TO BE TRAPPED IN THE RENAL MEDULLA
High medullary osmolarity results from ______ of sodium and ______ of potassium, chloride, and other ions from the thick ascending loop of Henle into the interstitium.
active transport, co-transport
161
LOOP OF HENLE CHARACTERISTICS THAT CAUSE SOLUTES TO BE TRAPPED IN THE RENAL MEDULLA
The thick ascending limb is nearly ______, preventing ______.
water-impermeable, osmotic flow
162
LOOP OF HENLE CHARACTERISTICS THAT CAUSE SOLUTES TO BE TRAPPED IN THE RENAL MEDULLA
Active transport results in more ______ than ______ in the medullary interstitium.
solutes, water
163
LOOP OF HENLE CHARACTERISTICS THAT CAUSE SOLUTES TO BE TRAPPED IN THE RENAL MEDULLA
______ of sodium chloride from the thin ascending limb further increases solute concentration.
Passive reabsorption
164
Steps Involved in Causing Hyperosmotic Renal Medullary Interstitium:
STEP 1: Assume the loop of Henle has fluid with a concentration of 300 mOsm/L, equal to that from the proximal tubule.
STEP 2: The active ion pump in the thick ascending limb lowers tubular concentration and raises interstitial concentration, creating a 200-mOsm/L gradient.
STEP 3: The descending limb and interstitial fluid reach osmotic equilibrium as water osmoses out, maintaining interstitial osmolarity at 400 mOsm/L and creating a 200-mOsm/L sodium chloride gradient.
STEP 4: Fluid from the proximal tubule enters the loop, causing hyperosmotic fluid from the descending limb to flow into the ascending limb, where ions are pumped out, raising interstitial osmolarity to 500 mOsm/L.
165
ROLE OF DISTAL TUBULE AND COLLECTING DUCTS IN EXCRETING CONCENTRATED URINE
ROLE OF DISTAL TUBULE:
- Tubular fluid entering the distal convoluted tubule is ______ and the early distal tubule further ______ the fluid
dilute, dilutes
166
ROLE OF DISTAL TUBULE AND COLLECTING DUCTS IN EXCRETING CONCENTRATED URINE
ROLE OF COLLECTING DUCTS:
- Water reabsorption depends on ______; without ______, it's nearly ______, further ______ urine while ______ solutes
ADH, ADH, impermeable, diluting, reabsorbing
167
ROLE OF DISTAL TUBULE AND COLLECTING DUCTS IN EXCRETING CONCENTRATED URINE
ROLE OF COLLECTING DUCTS:
- With high ______, the tubule becomes ______, allowing ______
ADH, water-permeable, reabsorption
168
ROLE OF DISTAL TUBULE AND COLLECTING DUCTS IN EXCRETING CONCENTRATED URINE
ROLE OF COLLECTING DUCTS:
- More water is ______ in the medullary collecting ducts, carried away by the ______
reabsorbed, vasa recta
169
ROLE OF DISTAL TUBULE AND COLLECTING DUCTS IN EXCRETING CONCENTRATED URINE
ROLE OF COLLECTING DUCTS:
- High ADH levels increase water ______, enabling ______ urine formation while excreting normal ______ amounts
permeability, concentrated, solute
170
UREA CONTRIBUTES TO HYPEROSMOTIC RENAL MEDULLARY INTERSTITIUM AND FORMATION OF CONCENTRATED URINE
Urea contributes ______% to ______% of the osmolarity (______–______ mOsm/L) of the renal medullary interstitium in maximally concentrated urine.
40, 50, 500, 600
171
UREA CONTRIBUTES TO HYPEROSMOTIC RENAL MEDULLARY INTERSTITIUM AND FORMATION OF CONCENTRATED URINE
Unlike sodium chloride, urea is ______ reabsorbed from the tubule.
passively
172
UREA CONTRIBUTES TO HYPEROSMOTIC RENAL MEDULLARY INTERSTITIUM AND FORMATION OF CONCENTRATED URINE
During water ______ and ______ ADH levels, large amounts of urea are reabsorbed from the inner medullary collecting ducts into the interstitium.
deficits, high
173
UREA CONTRIBUTES TO HYPEROSMOTIC RENAL MEDULLARY INTERSTITIUM AND FORMATION OF CONCENTRATED URINE
The ______ and ______ are impermeable to urea, leading to minimal reabsorption.
ascending loop of Henle, distal tubules
174
UREA CONTRIBUTES TO HYPEROSMOTIC RENAL MEDULLARY INTERSTITIUM AND FORMATION OF CONCENTRATED URINE
______ ADH increases water reabsorption in the cortical collecting tubule, raising urea ______ due to low ______.
High, concentration, permeability
175
UREA CONTRIBUTES TO HYPEROSMOTIC RENAL MEDULLARY INTERSTITIUM AND FORMATION OF CONCENTRATED URINE
In the inner medullary collecting ducts, further water ______ raises urea concentration, causing ______ into the renal interstitial fluid.
Urea transporters ______ and ______, activated by ______, enhance this diffusion and reabsorption.
reabsorption, diffusion, UT-A1, UT-A3, ADH
176
UREA CONTRIBUTES TO HYPEROSMOTIC RENAL MEDULLARY INTERSTITIUM AND FORMATION OF CONCENTRATED URINE
The combined movement of water and urea maintains ______ urea concentrations in the tubular fluid and urine.
high
177
Recirculation of Urea from Collecting Duct to Loop of Henle Contributes to Hyperosmotic Renal Medulla
Rate of urea excretion is determined mainly by the following:
concentration of urea in the plasma
glomerular filtration rate (GFR)
renal tubular urea reabsorption
178
COUNTERCURRENT EXCHANGE IN ______ PRESERVES HYPEROSMOLARITY OF RENAL MEDULLA
VASA RECTA
179
COUNTERCURRENT EXCHANGE IN VASA RECTA PRESERVES HYPEROSMOLARITY OF RENAL MEDULLA
Special features of the renal medullary blood flow contribute to the preservation of the high solute concentrations:
- The medullary blood flow is ______, accounting for ______ than Medullary blood flow is low, making up less than ______% of total renal blood flow. This sluggish flow meets metabolic needs while minimizing solute ______ from the medullary interstitium.
low, less, 5, loss
180
COUNTERCURRENT EXCHANGE IN VASA RECTA PRESERVES HYPEROSMOLARITY OF RENAL MEDULLA
Special features of the renal medullary blood flow contribute to the preservation of the high solute concentrations:
- The ______ serve as countercurrent exchangers, minimizing the ______ of solutes from the medullary interstitium.
vasa recta, washout
181
SUMMARY OF URINE-CONCENTRATING MECHANISM AND CHANGES IN OSMOLARITY IN DIFFERENT TUBULAR SEGMENTS
Proximal Tubule:
- About ______% of filtered electrolytes are reabsorbed in the proximal tubule
- Aided by ______
- Osmolarity of the fluid around ______ mOsm/L, similar to ______
65, aquaporin 1 (AQP-1), 300, glomerular filtrate
182
SUMMARY OF URINE-CONCENTRATING MECHANISM AND CHANGES IN OSMOLARITY IN DIFFERENT TUBULAR SEGMENTS
Descending Loop of Henle:
- As fluid flows down the descending loop of Henle, water is absorbed into the ______
- Increasing the osmolarity of the tubular fluid to nearly ______ mOsm/L in the presence of ______
medulla, 1200, high ADH
183
SUMMARY OF URINE-CONCENTRATING MECHANISM AND CHANGES IN OSMOLARITY IN DIFFERENT TUBULAR SEGMENTS
Thin Ascending Loop of Henle:
- The thin ascending limb is ______ to water but reabsorbs ______
- ______ of sodium chloride into the medullary interstitium; ______ the tubular fluid
- Urea from the medullary interstitium diffuses back into the ascending limb, contributing to ______
impermeable, sodium chloride, Passive diffusion, dilutes, urea recycling
184
SUMMARY OF URINE-CONCENTRATING MECHANISM AND CHANGES IN OSMOLARITY IN DIFFERENT TUBULAR SEGMENTS
Thick Ascending Loop of Henle:
- The thick part of the ascending loop of Henle is also virtually ______ to water
- Large amounts of sodium, chloride, potassium, and other ions are ______ from the tubule into the medullary interstitium
- Fluid becomes very dilute, falling to a concentration of about ______ mOsm/L
impermeable, actively transported, 140
185
SUMMARY OF URINE-CONCENTRATING MECHANISM AND CHANGES IN OSMOLARITY IN DIFFERENT TUBULAR SEGMENTS
Early Distal Tubule:
- Has properties similar to those of the ______
- Further dilution of the tubular fluid to about ______ mOsm/L occurs as ______ are reabsorbed while ______ remains in the tubule
thick ascending loop of Henle, 100, solutes, water
186
SUMMARY OF URINE-CONCENTRATING MECHANISM AND CHANGES IN OSMOLARITY IN DIFFERENT TUBULAR SEGMENTS
Late Distal Tubule and Cortical Collecting Tubules:
- Osmolarity of the fluid depends on the level of ______
- High ______, tubules are highly ______ to water; water are ______
- Absence of ______, little water is reabsorbed in the late distal tubule and cortical collecting tubule; osmolarity ______ even further
ADH, ADH levels, permeable, reabsorbed, ADH, decreases
187
SUMMARY OF URINE-CONCENTRATING MECHANISM AND CHANGES IN OSMOLARITY IN DIFFERENT TUBULAR SEGMENTS
Inner Medullary Collecting Ducts:
- The concentration of fluid in the inner medullary collecting ducts also depends on ______ and the surrounding ______ established by the ______
ADH, medullary interstitium osmolarity, countercurrent mechanism
188
Disorders of Urinary Concentrating Ability
Abnomalities:
- Inappropriate secretion of ADH
- Impairment of the countercurrent mechanism
- Inability of the distal tubules, collecting tubules, and collecting ducts to respond to ADH
189
Failure to Produce ADH: ______
Central Diabetes Insipidus
190
Failure to Produce ADH: Central Diabetes Insipidus
- Inability to produce or release ______ from the ______
- Caused by ______ or ______, or it can be ______
- Results in the formation of a large volume of ______ urine (>15 L/day)
ADH, posterior pituitary, head injuries, infections, congenital, dilute
191
Inability of Kidneys to Respond to ADH: ______
Nephrogenic Diabetes Insipidus
192
Inability of Kidneys to Respond to ADH: Nephrogenic Diabetes Insipidus
- ______ cannot respond appropriately
- Due to failure of the ______ to form a hyperosmotic renal medullary interstitium or failure of the ______ to respond to ADH
- Large volumes of ______ urine are formed; causes ______
Renal tubular segments, countercurrent mechanism, distal and collecting tubules and ducts, dilute, dehydration
193
CONTROL OF EXTRACELLULAR FLUID OSMOLARITY AND SODIUM CONCENTRATION
Estimating Plasma Osmolarity From Plasma Sodium Concentration
- Sodium ions and associated anions (mainly ______ and ______) account for about ______% of extracellular osmoles, while glucose and urea contribute around ______% to ______%. ______ easily permeates cell membranes and exerts little effective osmotic pressure under steady-state conditions. Thus, sodium ions and associated anions are the main determinants of fluid ______ across cell membranes. This allows for simultaneous discussion of osmolarity control and sodium ion concentration control.
bicarbonate, chloride, 94, 3, 5, Urea, movement
194
Two primary systems involved in regulating the concentration of sodium and osmolarity of extracellular fluid:
the osmoreceptor-ADH system
the thirst mechanism.
195
OSMORECEPTOR-ADH FEEDBACK SYSTEM
Osmoreceptor-ADH feedback system operation:
Water deficit
(up) Extracellular osmolarity
(up) ADH secretion
(up) Plasma ADH
(up) H2O permeability in distal tubules, collecting ducts
(up) H2O reabsorption
(down) H2O excreted
196
ADH SYNTHESIS IN SUPRAOPTIC AND PARAVENTRICULAR NUCLEI OF HYPOTHALAMUS AND ADH RELEASE FROM POSTERIOR PITUITARY
- ADH is synthesized in the ______ (five-sixths) and ______ (one-sixth) nuclei of the ______.
- These nuclei send ______ to the posterior pituitary for ADH transport.
- ______ osmolarity triggers nerve impulses that lead to ______ and ______ from secretory granules in the posterior pituitary.
- Released ADH enters ______, rapidly increasing ______ levels to alter renal water excretion.
supraoptic, paraventricular, hypothalamus
axonal extensions
Increased, calcium entry, ADH release
circulation, plasma
197
STIMULATION OF ADH RELEASE BY DECREASED ARTERIAL PRESSURE AND/ OR DECREASED BLOOD VOLUME
Cardiovascular reflexes:
- the arterial baroreceptor reflexes
- the cardiopulmonary reflexes
198
STIMULATION OF ADH RELEASE BY DECREASED ARTERIAL PRESSURE AND/ OR DECREASED BLOOD VOLUME
Stimuli increase ADH secretion:
- decreased arterial pressure
- decreased blood volume.
199
CENTRAL NERVOUS SYSTEM CENTERS FOR THIRST
The anteroventral wall of the third ventricle promotes ______ and stimulates ______.
ADH release, thirst
200
CENTRAL NERVOUS SYSTEM CENTERS FOR THIRST
______ stimulation of the ______ triggers immediate drinking.
Electrical, preoptic nucleus
201
CENTRAL NERVOUS SYSTEM CENTERS FOR THIRST
Neurons in the thirst center act as ______, responding to ______ salt solutions initiating drinking behavior.
osmoreceptors, hypertonic
202
CENTRAL NERVOUS SYSTEM CENTERS FOR THIRST
Increased ______ in the third ventricle encourages drinking
cerebrospinal fluid osmolarity
203
STIMULI FOR THIRST
Increased ______ causes intracellular dehydration in thirst centers.
extracellular fluid osmolarity
204
STIMULI FOR THIRST
Decreased ______ and ______ stimulate thirst.
extracellular fluid volume, arterial pressure
205
STIMULI FOR THIRST
______ is a key stimulus for thirst.
Angiotensin II
206
STIMULI FOR THIRST
Dryness of the ______ and ______ elicits thirst.
mouth, esophagus
207
STIMULI FOR THIRST
______ and ______ stimuli also influence thirst.
Gastrointestinal, pharyngeal
208
THRESHOLD FOR OSMOLAR STIMULUS OF DRINKING
The kidneys excrete water to remove excess ______, even in ______.
solutes, dehydration
209
THRESHOLD FOR OSMOLAR STIMULUS OF DRINKING
______ increases extracellular sodium concentration and osmolarity.
Evaporation
210
THRESHOLD FOR OSMOLAR STIMULUS OF DRINKING
Thirst is activated when sodium rises about ______ mEq/L above normal.
2
211
Disorders of Thirst and Water Intake
______: Excessive thirst; occasionally occurs in the absence of known physiological stimuli for thirst
Polydipsia
212
Disorders of Thirst and Water Intake
______: May be caused by mental illnesses (schizophrenia or obsessive-compulsive disorders) and can lead to hyponatremia
Psychogenic polydipsia
213
Disorders of Thirst and Water Intake
______: Rare but usually results from lesions to the hypothalamic thirst centers caused by trauma, infection, or surgery.
Adipsia
214
INTEGRATED RESPONSES OF OSMORECEPTOR-ADH AND THIRST MECHANISMS
- Osmoreceptor-ADH and thirst mechanisms manage ______ and ______ during dehydration.
- High ______ has minimal impact if both mechanisms are working.
- If one mechanism fails, the other can help if fluid intake is ______.
- Both mechanisms failing leads to poor ______ and ______ control.
- No other system effectively regulates ______ without these mechanisms.
osmolarity, sodium, salt intake, adequate, sodium, osmolarity, plasma sodium
215
Role of Angiotensin II and Aldosterone in Controlling Extracellular Fluid Osmolarity and Sodium Concentration
- Regulates ______: prevents ______ at low intake, allows ______ at high intake.
sodium reabsorption, loss, excretion
216
Role of Angiotensin II and Aldosterone in Controlling Extracellular Fluid Osmolarity and Sodium Concentration
Increases ______ with minimal effect on sodium concentration, except in extremes.
extracellular fluid volume
217
Role of Angiotensin II and Aldosterone in Controlling Extracellular Fluid Osmolarity and Sodium Concentration
______ remains stable without ______, despite sodium intake changes.
Plasma sodium, aldosterone
218
Role of Angiotensin II and Aldosterone in Controlling Extracellular Fluid Osmolarity and Sodium Concentration
______ is more crucial than angiotensin II and aldosterone for plasma sodium regulation.
ADH-thirst mechanism
219
Salt-Appetite Mechanism for Controlling Extracellular Fluid Sodium Concentration and Volume
______ to obtain salt during ______, crucial for herbivores on low-sodium diets.
Regulatory drive, sodium deficiency
220
Salt-Appetite Mechanism for Controlling Extracellular Fluid Sodium Concentration and Volume
Main stimuli for salt appetite: ______ and ______.
sodium deficits, decreased blood volume/pressure
221
Salt-Appetite Mechanism for Controlling Extracellular Fluid Sodium Concentration and Volume
Neuronal mechanism for salt appetite is similar to ______, involving the ______ region; ______ affect both.
thirst, AV3V, lesions
222
REGULATION OF EXTRACELLULAR FLUID POTASSIUM CONCENTRATION AND POTASSIUM EXCRETION
The ECF potassium concentration normally is regulated at about ______ mEq/L, seldom rising or falling more than ±______ mEq/L
4.2, 0.3
223
REGULATION OF EXTRACELLULAR FLUID POTASSIUM CONCENTRATION AND POTASSIUM EXCRETION
Increase in plasma potassium concentration of only 3 to 4 mEq/L can cause ______
cardiac arrhythmias
224
REGULATION OF EXTRACELLULAR FLUID POTASSIUM CONCENTRATION AND POTASSIUM EXCRETION
Higher concentrations can lead to ______ or ______
cardiac arrest, fibrillation
225
REGULATION OF EXTRACELLULAR FLUID POTASSIUM CONCENTRATION AND POTASSIUM EXCRETION
More than ______% of total body potassium is contained in the cells, and only ______% in ECF
98, 2
226
REGULATION OF EXTRACELLULAR FLUID POTASSIUM CONCENTRATION AND POTASSIUM EXCRETION
70-kg adult: ______ mEq of potassium are in the cells, only about ______ mEq in the ECF
3920, 59
227
REGULATION OF EXTRACELLULAR FLUID POTASSIUM CONCENTRATION AND POTASSIUM EXCRETION
Potassium in a single meal may be as high as ______ mEq
50
228
REGULATION OF EXTRACELLULAR FLUID POTASSIUM CONCENTRATION AND POTASSIUM EXCRETION
Daily potassium intake ranges between ______ and ______ mEq/day
50, 200
229
REGULATION OF EXTRACELLULAR FLUID POTASSIUM CONCENTRATION AND POTASSIUM EXCRETION
Only ______% to ______% of potassium intake is excreted in feces; ______ are primarily responsible for the excretion
5, 10, kidneys
230
REGULATION OF EXTRACELLULAR FLUID POTASSIUM CONCENTRATION AND POTASSIUM EXCRETION
______ can serve as an overflow site for excess ECF during ______ or source of potassium during ______
Cells, hyperkalemia, hypokalemia
231
REGULATION OF EXTRACELLULAR FLUID POTASSIUM CONCENTRATION AND POTASSIUM EXCRETION
Redistribution of potassium between ______ and ______ compartments provides a first line of defense against changes in ______
ICF, ECF, extracellular fluid concentration
232
REGULATION OF INTERNAL POTASSIUM DISTRIBUTION
After ingestion of a potassium-rich meal, ______ would rise to a dangerous level if the ingested potassium did not move into the cells ______
extracellular fluid potassium concentration, rapidly
233
REGULATION OF INTERNAL POTASSIUM DISTRIBUTION
Most ingested potassium rapidly moves into cells until ______ can eliminate ______
kidneys, excess
234
REGULATION OF INTERNAL POTASSIUM DISTRIBUTION
Between meals, ______ stays constant as cells release potassium to balance kidney ______
plasma potassium, excretion
235
OVERVIEW OF RENAL POTASSIUM EXCRETION
Renal potassium excretion is determined
by:
- Rate of potassium filtration (GFR × plasma potassium concentration)
- Rate of potassium reabsorption by tubules
- Rate of potassium secretion by tubules
236
OVERVIEW OF RENAL POTASSIUM EXCRETION
Normal rate of potassium filtration: ______ mEq/day (GFR, 180 L/day × plasma potassium concentration, 4.2 mEq/L)
756
237
OVERVIEW OF RENAL POTASSIUM EXCRETION
Severe decreases in GFR can cause ______ and ______
potassium accumulation, hyperkalemia
238
OVERVIEW OF RENAL POTASSIUM EXCRETION
Potassium reabsorption:
- ______% in proximal tubule
- ______% to ______% in loop of Henle
- ______ rates in collecting tubules and collecting ducts
65, 25, 30, Variable
239
OVERVIEW OF RENAL POTASSIUM EXCRETION
In proximal tubule and loop of Henle, relatively ______ is reabsorbed
constant fraction
240
OVERVIEW OF RENAL POTASSIUM EXCRETION
Daily variation of potassium excretion is not due to changes in ______ or ______ reabsorption
proximal tubule, loop of Henle
241
OVERVIEW OF RENAL POTASSIUM EXCRETION
Collecting tubules and collecting ducts reabsorb ______ at ______ rates, depending on ______
potassium, variable, potassium intake
242
Variable Potassium Secretion in Distal and Collecting Tubules Mediates Most Daily Changes in Potassium
Principal cells of ______ and cortical ______ are most important sites for regulating potassium excretion
late distal tubules, collecting tubules
243
Variable Potassium Secretion in Distal and Collecting Tubules Mediates Most Daily Changes in Potassium
With normal potassium intake (______ mEq/day):
- Kidneys must excrete ______ mEq/day
- ______ mEq lost in feces
- ______ mEq/day secreted into distal and collecting tubules
100, 92, 8, 60
244
Variable Potassium Secretion in Distal and Collecting Tubules Mediates Most Daily Changes in Potassium
With high potassium intake:
- Extra excretion achieved by ______ secretion into distal and collecting tubules
- Can exceed amount in ______
increased, glomerular filtrate
245
Variable Potassium Secretion in Distal and Collecting Tubules Mediates Most Daily Changes in Potassium
With low potassium intake:
- ______ secretion in distal and collecting tubules
- ______ reabsorption by intercalated cells
- Excretion can fall to <______% of glomerular filtrate (<10 mEq/day)
- Severe ______ possible below this level
Decreased, Increased, 1, hypokalemia
246
Variable Potassium Secretion in Distal and Collecting Tubules Mediates Most Daily Changes in Potassium
Daily regulation occurs mainly in ______ and ______ tubules
- Potassium can be ______ or ______ depending on the body’s needs
late distal, cortical collecting, reabsorbed, secreted
247
PRINCIPAL CELLS OF LATE DISTAL AND CORTICAL COLLECTING TUBULES SECRETE ______
POTASSIUM
248
PRINCIPAL CELLS OF LATE DISTAL AND CORTICAL COLLECTING TUBULES SECRETE POTASSIUM
Make up most cells in ______ and ______ tubules
late distal, cortical collecting
249
PRINCIPAL CELLS OF LATE DISTAL AND CORTICAL COLLECTING TUBULES SECRETE POTASSIUM
Two-step potassium secretion:
- Na+-K+ ATPase pump moves K+ from interstitium into cell
- Passive diffusion of K+ into tubular fluid
250
PRINCIPAL CELLS OF LATE DISTAL AND CORTICAL COLLECTING TUBULES SECRETE POTASSIUM
Two types of K+ channels in luminal membrane:
- Renal outer medullary potassium (ROMK) channels
- “Big” potassium BK channels
251
PRINCIPAL CELLS OF LATE DISTAL AND CORTICAL COLLECTING TUBULES SECRETE POTASSIUM
Control of Potassium Secretion by Principal Cells:
Na+-K+ ATPase pump activity
Electrochemical gradient
Luminal membrane permeability
252
Intercalated Cells Can Reabsorb or Secrete Potassium:
Type A cells
Type B cells
253
Intercalated Cells Can Reabsorb or Secrete Potassium:
______
- Reabsorb K+ during severe depletion
Type A cells
254
Intercalated Cells Can Reabsorb or Secrete Potassium:
______
- Use hydrogen-potassium ATPase in luminal membrane
Type A cells
255
Intercalated Cells Can Reabsorb or Secrete Potassium:
______
- Exchange K+ for H+ ions
Type A cells
256
Intercalated Cells Can Reabsorb or Secrete Potassium:
______
- Enhanced during hypokalemia
Type A cells
257
Intercalated Cells Can Reabsorb or Secrete Potassium:
______
- Causes alkalosis
Type A cells
258
Intercalated Cells Can Reabsorb or Secrete Potassium:
______
- Active during excess K+
Type B cells
259
Intercalated Cells Can Reabsorb or Secrete Potassium:
______
- Opposite function to Type A
Type B cells
260
Intercalated Cells Can Reabsorb or Secrete Potassium:
______
- Use hydrogen-potassium ATPase on basolateral membrane
Type B cells
261
SUMMARY OF MAJOR FACTORS THAT REGULATE POTASSIUM SECRETION
Factors that stimulate potassium secretion:
- Increased extracellular fluid potassium concentration
- Increased aldosterone
- Increased tubular flow rate
262
SUMMARY OF MAJOR FACTORS THAT REGULATE POTASSIUM SECRETION
Factor that decreases potassium secretion:
Increased hydrogen ion concentration (acidosis)
263
______ Extracellular Fluid Potassium Concentration Stimulates Potassium Secretion
Increased
264
Aldosterone ______ Potassium Secretion
Stimulates
265
______ Extracellular Potassium Ion Concentration Stimulates Aldosterone Secretion
Increased
266
Blockade of Aldosterone Feedback System Greatly ______ Potassium Regulation
Impairs
267
______ Distal Tubular Flow Rate Stimulates Potassium Secretion
Increased
268
Acute Acidosis ______ Potassium Secretion
Decreases
269
REGULATION OF RENAL CALCIUM EXCRETION AND EXTRACELLULAR CALCIUM ION CONCENTRATION
Normal extracellular calcium: ______ mEq/L
2.4
270
REGULATION OF RENAL CALCIUM EXCRETION AND EXTRACELLULAR CALCIUM ION CONCENTRATION
Plasma calcium distribution (total ______ mEq/L):
- ______% ionized (biologically active)
- ______% protein-bound
- ______% complexed with anions
5, 50, 40, 10
271
REGULATION OF RENAL CALCIUM EXCRETION AND EXTRACELLULAR CALCIUM ION CONCENTRATION
pH Effects on Calcium:
______: Decreases protein-bound calcium
Acidosis
272
REGULATION OF RENAL CALCIUM EXCRETION AND EXTRACELLULAR CALCIUM ION CONCENTRATION
pH Effects on Calcium:
______:
- Increases protein-bound calcium
- Higher risk of hypocalcemic tetany
Alkalosis
273
REGULATION OF RENAL CALCIUM EXCRETION AND EXTRACELLULAR CALCIUM ION CONCENTRATION
Calcium Balance:
- Daily intake: ~______ mg/day
- Fecal excretion: ~______ mg/day
- Body distribution:
______% in bone
______% in ECF
______% in ICF
1000, 900, 99, 0.1, 1.0
274
REGULATION OF RENAL CALCIUM EXCRETION AND EXTRACELLULAR CALCIUM ION CONCENTRATION
PTH Regulation:
Triggered by ______ calcium via ______
low, calcium-sensing receptors (CSRs)
275
REGULATION OF RENAL CALCIUM EXCRETION AND EXTRACELLULAR CALCIUM ION CONCENTRATION
PTH Regulation:
Three main effects:
- Stimulates bone resorption
- Activates vitamin D for intestinal absorption
- Increases renal tubular reabsorption
276
REGULATION OF RENAL CALCIUM EXCRETION AND EXTRACELLULAR CALCIUM ION CONCENTRATION
Functions in both ______ and ______ calcium regulation
short-term, long-term
277
Renal Calcium Excretion Formula:
Renal calcium excretion = calcium filtered - calcium reabsorbed
278
CONTROL OF CALCIUM EXCRETION BY THE KIDNEYS
Only ______% of plasma calcium is filtered
60
279
CONTROL OF CALCIUM EXCRETION BY THE KIDNEYS
Total reabsorption: ______% of filtered calcium
99
280
CONTROL OF CALCIUM EXCRETION BY THE KIDNEYS
Distribution of reabsorption:
- Proximal tubule: ______%
- Loop of Henle: ______-______%
- Distal/collecting tubules: ______-______%
65, 25, 30, 4, 9
281
CONTROL OF CALCIUM EXCRETION BY THE KIDNEYS
Proximal Tubular Calcium Reabsorption.
- Mainly ______ pathway
- ______% transcellular pathway via:
______ through electrochemical gradient
______ via calcium ATPase and Na-Ca counter-transport
paracellular, 20, Luminal entry, Basolateral exit
282
CONTROL OF CALCIUM EXCRETION BY THE KIDNEYS
Loop of Henle and Distal Tubule Calcium Reabsorption
Loop of Henle (______):
- ______% paracellular (______)
- ______% transcellular (______)
Thick Ascending Limb, 50, passive diffusion, 50, PTH-stimulated
283
CONTROL OF CALCIUM EXCRETION BY THE KIDNEYS
Loop of Henle and Distal Tubule Calcium Reabsorption
Distal Tubule:
- Mainly active ______ transport
- Uses ______, ______, and ______
- Regulated by ______, ______, and ______
transcellular, calcium channels, calcium- ATPase pump, Na-Ca counter-transport, PTH, vitamin D, calcitonin
284
Regulation of Tubular Calcium Reabsorption.
PTH:
- ______ controller
- Stimulates reabsorption in ______ and ______
- No effect on ______
Primary, loop of Henle, distal tubule, proximal tubule
285
Regulation of Tubular Calcium Reabsorption.
Volume Status:
- Volume expansion ______ reabsorption
- Volume depletion ______ reabsorption
decreases, increases
286
Regulation of Tubular Calcium Reabsorption.
Other Factors:
______ levels affect PTH secretion
pH effects:
- Acidosis ______ excretion
- Alkalosis ______ excretion
______ respond to calcium levels
______ influences excretion
Phosphate, increases, decreases, CSRs, Dietary calcium intake
