Download ppt_E1ch01_regulation of water content

1
People with kidney failure (腎衰竭) must
be treated immediately.
2
They can either
undergo a kidney transplant (移植).
transplanted
kidney
3
They can either
use a kidney machine (洗腎機).
4
They can either
undergo peritoneal dialysis (腹膜透析).
dialysis
fluid in
4 hours
later
dialysis
fluid out
5
They also have to make
some changes in their diet.
e.g. avoid taking too much
fluid and high-protein food.
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1.1 Importance of regulating
water content
water
intake
water
loss
balanced
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Water Balance in the Body
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•Figure 20-2
• Land animals
manage water
budgets by
drinking and
eating moist
foods and
using
metabolic
water
•Water
•Water
•balance in a
•balance in
•kangaroo rat
•a human
•(2 mL/day)
•(2,500 mL/day)
•Ingested
•Ingested
•Ingested
•in food
•in food (0.2 mL)
•in liquid
•(750 mL)
•(1,500 mL)
•Water
•gain
•Derived from
•Derived from
•metabolism (1.8 mL)
•metabolism (250 mL)
•Urine
•Water
•Feces (0.09 mL)
•(0.45 mL)
•Urine •Feces (100 mL)
•(1,500 mL)
•loss
•Evaporation (1.46 mL)
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•Evaporation (900 mL)
1.1 Importance of regulating
water content
• if water intake  water loss
 affects water content in blood
 affects water potential of tissue fluid
 water enters or leaves cells by osmosis
 cells do not function properly or
even die
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1.1 Importance of regulating
water content
control of the water content
in the body
osmoregulation (滲透調節)
done by kidneys of
urinary system (泌尿系統)
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1.1 Importance of regulating water content
1
Osmoregulation keeps the
water potential of the tissue fluid
and hence the water potential of
the cells stable, so that cells can
function properly to sustain life.
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1.1 Importance of regulating water content
2 The kidneys
of the urinary
system are the major organs for
osmoregulation.
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1.2 The human urinary system
(dorsal aorta)
(posterior
vena cava)
(renal artery)
(renal vein)
female
•Despite their small size, the two
kidneys receive an enormous blood
flow — about 1.2 litres/min /2000 litres
per day in an adult — which is a
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quarter of the total output of the heart
1.2 The human urinary system
kidneys
ureters
female
urinary
bladder
15
1.2 The human urinary system
control
urination
female
sphincter
muscles
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1.2 The human urinary system
female
male
urethra
17
1.2 The human urinary system
ureters
urinary bladder
(vas deferens)
urethra
(penis)
male
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1.2 The human urinary system
1.1
Video
Examination of the mammalian
urinary system
1 Examine the urinary
system of a dissected
rat.
2 Identify the structures.
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1.2 The human urinary system
Structure of the kidney
3D model
cortex (皮質)
medulla (髓)
renal vein
renal artery
ureter
pelvis (腎盂)
20
1.2 The human urinary system
Structure of the kidney
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1.2 The human urinary system
Structure of the kidney
cortex
medulla
22
1.2 The human urinary system
Structure of the kidney
branch from
renal artery
branch from
renal vein
23
1.2 The human urinary system
Structure of the kidney
nephron (腎元)
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Key functions of most
excretory systems:
•Excretory
•tubule
•Filtrate
•Filtration: pressurefiltering of body fluids
•Capillary
•Reabsorption:
reclaiming valuable
solutes
•Reabsorption
•Secretion
•Urine
•Secretion: adding
toxins and other
solutes from the body
fluids to the filtrate
•Filtration
•Excretion
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1.2 The human urinary system
Structure of the kidney
proximal
convoluted
tubule
Bowman’s
capsule
distal convoluted tubule
kidney
tubule
loope of Henle
collecting duct
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1.2 The human urinary system
Structure of the kidney
proximal
convoluted
tubule
Bowman’s
capsule
loop of Henle
collecting duct
distal convoluted tubule
flow of
urine
from
another
nephron
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1.2 The human urinary system
Structure of the kidney
glomerulus
Bowman’s
capsule
kidney
tubule
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Capillary Beds of the Nephron
• Every nephron has two capillary beds
– Glomerulus
– Peritubular capillaries
• Each glomerulus is:
– Fed by an afferent arteriole
– Drained by an efferent arteriole
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1.2 The human urinary system
Blood supply of a nephron
efferent arteriole
glomerulus
afferent arteriole
branch from
renal artery
branch from
renal vein
Peritubular
capillary
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1.2 The human urinary system
1.2
Examination of the mammalian kidney
1 Put a fresh pig’s kidney on a dissection
tray.
2 Examine whether there are tubes coming
from the kidney. Remove any fatty
tissues and identify the tubes.
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1.2 The human urinary system
1.2
3 Cut the kidney longitudinally.
32
1.2 The human urinary system
1.2
4 Identify various structures
of the kidney.
5 Draw a labelled diagram
of the longitudinal section
of the kidney.
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1.2 The human urinary system
1
Parts of
urinary
system
Function
Purify blood and form
Kidneys
urine
Carry urine from kidneys
Ureters
to urinary bladder
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1.2 The human urinary system
1
Parts of
Function
urinary
system
Urinary
Stores urine temporarily
bladder
Carries urine from urinary
Urethra bladder to the outside
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1.2 The human urinary system
2 Structure of a nephron:
a A nephron consists of the
Bowman’s capsule , the
proximal convoluted tubule ,
the distal convoluted tubule
and the collecting duct .
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1.2 The human urinary system
2 Structure of a nephron:
b The Bowman’s capsule encloses
a network of capillaries called the
glomerulus . The kidney tubule
is surrounded by another network
of capillaries which is continuous
with the glomerulus.
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1.3 Functioning of a nephron
• urine is formed by mainly two
processes:
ultrafiltration reabsorption
(重吸收)
(超濾)
38
1.3 Functioning of a nephron
• and:
ultrafiltration reabsorption
Active secretion
39
Mechanism of Urine Formation
• Urine formation
and adjustment
of blood
composition
involve three
major processes
– Glomerular
filtration
– Tubular
reabsorption
– Active
Secretion
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•Figure 24.9
1.3 Functioning of a nephron
1 Ultrafiltration
Bowman’s capsule
• blood is under high
hydrostatic pressure
• capillary wall is
differentially permeable
 forces small molecules
through the thin walls
glomerulus
41
1.3 Functioning of a nephron
1 Ultrafiltration
urea
salts
glucose
water
amino
acids
42
1.3 Functioning of a nephron
1 Ultrafiltration
• fluid filtered into the
Bowman’s capsule:
glomerular filtrate
to proximal convoluted tubule
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1.3 Functioning of a nephron
1 Ultrafiltration
• composition similar to plasma
water
glucose
amino acids
salts
urea
plasma
proteins

to proximal convoluted tubule
44
Net Filtration Pressure (NFP) _
ref only
• The pressure responsible for filtrate
formation
• NFP equals the glomerular hydrostatic
pressure (HPg) minus the osmotic pressure
of glomerular blood (OPg) combined with the
capsular hydrostatic pressure (HPc)
NFP = HPg – (OPg + HPc)
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Glomerular Filtration Rate (GFR)
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•Figure 24.10
1.3 Functioning of a nephron
2 Reabsorption
• absorption of useful substances and most
of the water from the filtrate to the blood
•Your kidneys filter
approximately 200L of
plasma/day
•99% of the filtrate gets
reabsorbed, leaving 1 -2 L
of urine per day
47
1.3 Functioning of a nephron
2 Reabsorption
to renal vein
flow
of
urine
from renal
artery
48
Sodium Reabsorption: Primary
Active Transport_ ref only
Tubule
lumen
with
renal
fluid
49
Glucose Reabsorption: Secondary
Active Transport
50
Reabsorption: Both Primary and
secondary Active Transport
• Sodium reabsorption is almost
always by active transport
– Na+ enters the tubule cells
from the lumen / filtrate
– Na+ is actively transported
out of the tubules by a Na+K+ ATPase pump
• From there it moves to
peritubular capillaries
• Na+ reabsorption provides the
energy and the means for
reabsorbing most other solutes
51
Reabsorption by PCT Cells
52
•Figure 24.12
Reabsorption by PCT Cells
• Active pumping of Na+ drives
reabsorption of:
– Water by osmosis
– Anions by diffusion
– Organic nutrients and selected ions by
secondary active transport
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Reabsorption by PCT Cells
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•Figure 24.12
1.3 Functioning of a nephron
2 Reabsorption
proximal convoluted tubule
blood
glucose
amino acids
water
salts
amino acids
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1.3 Functioning of a nephron
2 Reabsorption
Substance
reabsorbed
Process
Glucose
(100%)
Diffusion,
active transport
Amino acids
(100%)
Diffusion,
active transport
Water (99%) Osmosis
Salts (80%)
Diffusion,
active transport
Urea (50%)
Diffusion
Region where
reabsorption occurs
At proximal
convoluted tubule
only
At proximal
convoluted tubule,
loop of Henle, distal
convoluted tubule &
collecting duct
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Filtration Fraction
57
•Figure 19-5
1.3 Functioning of a nephron
2 Reabsorption
• kidney tubule is highly
coiled to increase the
surface area and the
time for reabsorption
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1.3 Functioning of a nephron
2 Reabsorption
• remaining glomerular
filtrate in collecting duct
is called urine
mostly water with
salts, urea and other
metabolic waste
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3. Secretion
Essentially reabsorption in reverse,
where substances move from
peritubular capillaries or tubule cells
into filtrate
• Tubular secretion is important for:
– Eliminating undesirable substances such
as urea and uric acid
– Controlling blood pH
60
1.3 Functioning of a nephron
Proteins pass
through the walls of
the glomerulus and
the Bowman’s
capsule.
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1.3 Functioning of a nephron
It is the amino acids
that are filtered into
the Bowman’s
capsule and
reabsorbed later.
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1.3 Functioning of a nephron
1 In ultrafiltration, the high
hydrostatic pressure inside the
glomerulus forces small molecules
out of the blood into the Bowman’s
capsule.
63
1.3 Functioning of a nephron
1 The capillary wall of the glomerulus
is differentially permeable and
only allows small molecules to
pass through.
64
1.3 Functioning of a nephron
2 The composition of the glomerular
filtrate is similar to that of plasma
but it contains no plasma proteins .
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1.3 Functioning of a nephron
3 Reabsorption along the kidney
tubule:
a All
glucose and amino acids
in the glomerular filtrate are
reabsorbed into the blood by
diffusion and active transport.
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1.3 Functioning of a nephron
3 Reabsorption along the kidney
tubule:
b Most
water is reabsorbed by
osmosis.
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1.3 Functioning of a nephron
3 Reabsorption along the kidney
tubule:
c Some
salts are reabsorbed by
diffusion and active transport.
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1.3 Functioning of a nephron
3 Reabsorption along the kidney
tubule:
d Some
urea is reabsorbed by
diffusion and the rest is removed
in the urine.
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1.4 The role of the kidneys
Osmoregulation
• kidneys carry out osmoregulation by
controlling the amount of water
reabsorbed from the glomerular filtrate
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What The Color of Your Urine
Says About Your Health
•http://health.clevelandclinic.org/2013/10/w
hat-the-color-of-your-urine-says-aboutyou-infographic/
•
http://health.clevelandclinic.org/2013/10/what-the-color-of-your-urine-says-about-you-infographic/
71
1.4 The role of the kidneys
• the amount of water reabsorbed is
controlled by antidiuretic hormone
(ADH) (抗利尿激素)
• secretion of ADH is controlled by
the hypothalamus (下丘腦)
72
Diuresis
• Diuretics are a group of drugs given to
help the body eliminate excess fluid
through the kidneys. e.g. to treat
hypertension, glaucoma, etc
• Natural diuretic foods and drinks
•
•
•
•
•
Melon
Watercress
Coffee
Tea
Coke (caffeinated soda)
73
1.4 The role of the kidneys
hypothalamus
• has receptors to
detect water
content in blood
• controls secretion
of ADH
74
1.4 The role of the kidneys
pituitary gland
• secretes ADH
• ADH is transported
by blood
75
1.4 The role of the kidneys
• under the action of ADH
 permeability of the wall of the
collecting duct to water increases
 a greater proportion of water is
reabsorbed from the filtrate
• urine in different volumes and
concentrations can be formed
76
Urine Concentration
Osmolarity changes as filtrate flows through
the nephron
77
•Figure 20-4
Formation of Dilute Urine /
hypotonic urine
• Filtrate is hypotonic after passing through the loop of
Henle
• Dilute urine is created by allowing this filtrate to
continue into the renal pelvis
• This will happen as long as antidiuretic hormone
(ADH) is not being secreted
• Collecting ducts remain impermeable to water; no
further water reabsorption occurs
• Diuresis – hypotonic urine (large volume of)
78
Water Reabsorption
79
•Figure 20-5b
Water Reabsorption
Water movement in the collecting duct in the
presence of vasopressin (ADH)
80
•Figure 20-5a
Formation of Concentrated /
hypertonic Urine
• Antidiuretic hormone (ADH) inhibits diuresis
• In the presence of ADH, 99% of the water in filtrate is
reabsorbed
• ADH is the signal to produce concentrated urine
• The kidneys’ ability to respond depends upon the
high medullary osmotic gradient
81
The kidneys’ ability to make hypertonic urine
depends upon the high medullary osmotic gradient
•Click the
diagram to
see an
animation
82
1.4 The role of the kidneys
receptors in
hypothalamus
detected by
water content
increases
normal water
content in blood
pituitary gland
less ADH
wall of collecting
duct
less permeable
smaller proportion
of water
reabsorbed
larger volume
of dilute urine
83
1.4 The role of the kidneys
normal water
content in blood
water content
decreases
detected by
receptors in
hypothalamus
smaller volume of
concentrated urine
greater proportion
of water
reabsorbed
more permeable
wall of collecting
duct
more ADH
pituitary gland
84
•Proximal tubule
•NaCl •Nutrients
•HCO3– •H2O
•K+
•H+
•NH3
•Distal tubule
•H2O
•NaCl
•K+
•HCO3–
•H+
•CORTEX
•Filtrate
•H2O
•Salts (NaCl and others)
•Glucose; amino acids
•Thick segment
•of loop of
•of ascending
•Henle
•limb
•NaCl
•HCO3– ; H+ (control pH)
•Urea
•Descending limb
•H2O
•OUTER
•NaCl
•MEDULLA
•Some drugs
•Thin segment
•Collecting
•of ascending
•duct
•limb
•Key
•NaCl
•Active transport
•Passive transport
•Urea
•H2O
•INNER
•MEDULLA
85
Water Reabsorption
(reference)
The mechanism of vasopressin action
Cross-section of
kidney tubule
Medullary
Vasa
duct
interstitial
recta
lumen
fluid
Collecting
Collecting duct cell
600 mOsM
Filtrate
300 mOsm
H2O
600 mOsM
H2O
H2O
H2O
4
700 mOsM
Storage vesicles
Second
2
Exocytosis
messenger
signal
of vesicles
3
Aquaporin-2
1
cAMP
Vasopressin
water pores
Vasopressin
1
Vasopressin
2 Receptor activates
3 Cell inserts AQP2
receptor
4 Water is absorbed
binds to mem-
cAMP second
water pores into
by osmosis into
brane receptor.
messenger system.
apical membrane.
the blood.
•Figure 20-6
86
Water Reabsorption
(reference)
Cross-section of
kidney tubule
Medullary
Vasa
duct
interstitial
recta
lumen
fluid
Collecting
Filtrate
300 mOsm
Collecting duct cell
600 mOsM
600 mOsM
700 mOsM
1
Vasopressin
Vasopressin
receptor
1
Vasopressin
binds to mem-
87
brane receptor.
•Figure 20-6, step 1
Water Reabsorption
(reference)
Cross-section of
kidney tubule
Medullary
Vasa
duct
interstitial
recta
lumen
fluid
Collecting
Collecting duct cell
600 mOsM
Filtrate
600 mOsM
300 mOsm
700 mOsM
Second
2
messenger
signal
cAMP
1
Vasopressin
Vasopressin
receptor
1
Vasopressin
2
Receptor activates
binds to mem-
cAMP second
brane receptor.
messenger system.
88
•Figure 20-6, steps 1–2
Water Reabsorption
(reference)
Cross-section of
kidney tubule
Medullary
Vasa
duct
interstitial
recta
lumen
fluid
Collecting
Collecting duct cell
600 mOsM
Filtrate
600 mOsM
300 mOsm
700 mOsM
Storage vesicles
Second
2
Exocytosis
messenger
signal
of vesicles
3
Aquaporin-2
1
cAMP
Vasopressin
water pores
Vasopressin
receptor
1
Vasopressin
2 Receptor activates
3 Cell inserts AQP2
binds to mem-
cAMP second
water pores into
brane receptor.
messenger system.
apical membrane.
89
•Figure 20-6, steps 1–3
Water Reabsorption
(reference)
Cross-section of
kidney tubule
Medullary
Vasa
duct
interstitial
recta
lumen
fluid
Collecting
Collecting duct cell
600 mOsM
Filtrate
300 mOsm
H2O
600 mOsM
H2O
H2O
H2O
4
700 mOsM
Storage vesicles
Second
2
Exocytosis
messenger
signal
of vesicles
3
Aquaporin-2
1
cAMP
Vasopressin
water pores
Vasopressin
1
Vasopressin
2
Receptor activates
3 Cell inserts AQP2
receptor
4 Water is absorbed
binds to mem-
cAMP second
water pores into
by osmosis into
brane receptor.
messenger system.
apical membrane.
the blood.
•Figure 20-6, steps 1–4
90
Factors Affecting Vasopressin Release
91
•Figure 20-7
Water Balance
The effect of plasma osmolarity on vasopressin
secretion by the posterior pituitary
92
•Figure 20-8
1.4 The role of the kidneys
taking in
excess salts
higher concentration of salts in blood
smaller amount of salts and greater
proportion of water reabsorbed
smaller volume of urine with a high
salt concentration formed
(hypertonic urine)
93
Regulation of Kidney Function
• The osmolarity of the urine is regulated by
nervous and hormonal control of water
and salt reabsorption in the kidneys
• Antidiuretic hormone (ADH) increases
water reabsorption in the distal tubules and
collecting ducts of the kidney
94
Osmoreceptors
Thirst
in hypothalamus
Hypothalamus
Drinking reduces
blood osmolarity
to set point
ADH
Increased
permeability
Pituitary
•gland
Distal
tubule
•Collecting duct
H2O reabsorption helps
STIMULUS
prevent further
The release of ADH is
osmolarity
triggered when osmo-
increase
receptor cells in the
hypothalamus detect an
increase in the osmolarity of the blood
Homeostasis:
Blood osmolarity
95
What’s the effect of the following on
urine output :
• 1. a lot of water
• 2. a lot of salty foods
• 3. a large volume of salty solution. E.g
seawater
Assignment: 1.Explain why we cannot survive on
seawater as drinking water. 2. Write an essay on how
one can survive without drinking water while drifting on
a raft in the open ocean (>300 words)
96
1.4 The role of the kidneys
Excretion
• by forming urine
 to remove metabolic waste (e.g. urea)
97
1.4 The role of the kidneys
Excretion
• by forming urine
 to remove metabolic waste (e.g. urea)
• constantly produced
• high concentration is toxic
98
Diuretics
(reference)
• Chemicals that enhance the urinary output include:
– Any substance not reabsorbed
– Substances that exceed the ability of the renal tubules
to reabsorb it
• Osmotic diuretics include:
– High glucose levels – carries water out with the
glucose
– Alcohol – inhibits the release of ADH
– Caffeine and most diuretic drugs – inhibit sodium ion
reabsorption
– Lasix – inhibits Na+-K+-2Cl symporters
99
Physical Characteristics of Urine
(reference)
• Color and transparency
– Clear, pale to deep yellow (due to urobilin) -from
the breakdown of heme
– Concentrated urine has a deeper yellow color
– Drugs, vitamin supplements, and diet can change
the color of urine
– Cloudy urine may indicate infection of the urinary
tract
100
Concentrated urine has a deeper yellow color
101
Physical Characteristics of Urine
• Odor / smell
– Fresh urine is slightly
aromatic
– Standing urine develops
an ammonia odor
– Some drugs and
vegetables (asparagus)
alter the usual odor
102
Physical Characteristics of Urine
• pH
– Slightly acidic (pH 6)
with a range of 4.5 to
8.0
– Diet can alter pH
• Specific gravity
– Ranges from 1.001 to
1.035
– Dependent on solute
concentration
103
Chemical Characteristics of
Urine
• Urine is 95% water and 5% solutes
• Nitrogenous wastes include urea, uric acid, and
creatinine
• Other normal solutes include:
– Sodium, potassium, phosphate, and sulfate ions
– Calcium, magnesium, and bicarbonate ions
• Abnormally high concentrations of any urinary
constituents may indicate pathology
• Disease states alter urine composition dramatically
104
Functions of the Kidneys
• Regulation of extracellular fluid volume
and blood pressure
• Regulation of osmotic potential in blood
• Maintenance of ion balance
• Homeostatic regulation of pH
• Excretion of wastes
105
1.4 The role of the kidneys
1 Regulation of water content by
negative feedback mechanism:
hypothalamus
pituitary secretes less ADH
gland
kidneys
high water
content in blood
normal water content in blood
106
1.4 The role of the kidneys
In the kidneys:
a wall of collecting duct becomes less
permeable to water
b a smaller proportion of water
reabsorbed
c a larger volume of dilute urine is
formed
107
1.4 The role of the kidneys
1 Regulation of water content by
negative feedback mechanism:
hypothalamus
pituitary secretes less ADH
gland
kidneys
high water
content in blood
water content
in blood falls
normal water content in blood
108
1.4 The role of the kidneys
1 Regulation of water content by
negative feedback mechanism:
normal water content in blood
low water
content in blood
hypothalamus pituitary
gland
secretes
more
ADH
kidneys
109
1.4 The role of the kidneys
In the kidneys:
a wall of collecting duct becomes more
permeable to water
b a greater proportion of water
reabsorbed
c a smaller volume of concentrated
urine is formed
110
1.4 The role of the kidneys
1 Regulation of water content by
negative feedback mechanism:
normal water content in blood
water
content
low water
in
blood
rises
content in blood
secretes
more
kidneys
hypothalamus pituitary ADH
111
gland
1.4 The role of the kidneys
2 After excess salts are taken into the
body, the excess salts have to be
excreted. A smaller amount of
salts and a greater proportion of
water are reabsorbed. As a result, a
small volume of urine with a high
salt concentration is formed.
112
1.4 The role of the kidneys
3 Excretion is necessary because
metabolic waste is constantly
produced and a high concentration
of this waste is toxic to the body.
The kidneys form urine to remove
metabolic waste (e.g. urea) from the
blood.
113
1.5 The dialysis machine
Animation
• kidney machine
• helps remove metabolic waste by
haemodialysis (血液透析)
114
1.5 The dialysis machine
1 blood with
metabolic
waste
fresh
dialysis
fluid
pump dialysis
tubing
115
1.5 The dialysis machine
dialysis
tubing
same concentration of solutes
as normal plasma but has no
metabolic waste
fresh
dialysis
fluid
116
1.5 The dialysis machine
dialysis
tubing
dialysis
fluid
fresh
dialysis
fluid
constant temperature bath
117
1.5 The dialysis machine
differentially permeable
membrane of dialysis tubing
118
1.5 The dialysis machine
2 urea diffuses through the pores to
the dialysis fluid
119
1.5 The dialysis machine
3 glucose is retained in blood (no net
movement from blood to dialysis fluid
120
1.5 The dialysis machine
4 plasma proteins and blood cells are
too large to pass through the pores
121
1.5 The dialysis machine
5 ‘cleaned’
blood
used
dialysis
fluid
(with urea)
122
1.5 The dialysis machine
• each treatment lasts for 4-6 hours
• three times a week
• costly
123
Peritoneal dialysis
Peritoneal dialysis (PD) is a treatment for
patients with severe chronic kidney disease.
The process uses the patient's peritoneum
in the abdomen as a membrane across
which fluids and dissolved substances are
exchanged from the blood.
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Kidney transplant
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1.5 The dialysis machine
1 A dialysis machine removes
metabolic waste from the
patient’s blood.
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1.5 The dialysis machine
2 The dialysis fluid has the same
concentration of solutes as normal
plasma but no metabolic waste.
This allows metabolic waste to
diffuse from the patient’s blood to
the dialysis fluid while glucose
and other useful substances are
retained in the blood.
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1
Why may a person die quickly if the
kidneys fail to function?
When the kidneys fail to function, the
body cannot keep the water content in
blood stable for cells to function
properly.
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1
Why may a person die quickly if the
kidneys fail to function?
Besides, metabolic waste builds up in
blood which can cause death.
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2
How does a kidney machine treat
kidney failure?
A kidney machine removes metabolic
waste from the patient’s blood by
haemodialysis.
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3
Why can’t people with kidney
failure take in too much fluid and
high-protein food?
Excess proteins in the body are
converted to urea by the liver.
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3
Why can’t people with kidney
failure take in too much fluid and
high-protein food?
The failed kidney cannot remove
excess fluid and urea from the body.
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3
Why can’t people with kidney
failure take in too much fluid and
high-protein food?
Therefore, excessive intake of fluid
and high-protein food must be
avoided.
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Osmoregulation
is the
maintenance
of a stable
water content
in blood
done by
urinary system
main parts include
kidneys
detected by
hypothalamus
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hypothalamus
controls
secretion of
antidiuretic
hormone
controls
concentration
and volume of
kidneys
functional
units
nephrons
form
urine
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urine
kidneys
fail to
contains
function can
be treated by
by
ultrafiltration
reabsorption
dialysis machine
helps body
remove
metabolic waste
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