Transcript Water and Major Minerals

Water and Major Minerals
Water and Major Minerals
Water is an essential nutrient.
Can only last a few days without it.
The minerals maintain adequate
distribution of water in the body.
Water is inside and outside of
every cell in the body.
Water’s function in the body.
Carries nutrients to and waste
products from the cells.
Serves as a solvent and takes part
in metabolic reactions.
Acts as a lubricant around joints.
Regulates body temp and blood
volume.
Water Dissolves Salts and Follows Electrolytes
Cl Na+
+
H
_
O
H +
Na+
_
Cl -
The structural arrangement of the two hydrogen atoms and one oxygen
atom enables water to dissolve salts. Water’s role as a solvent is one of
its most valuable characteristics.
Figure 12-4
Page 402
Slide 4
Water homeostasis
60 % of adult weight is water.
Hypothalamus regulates water
intake by stimulating thirst.
Dehydration: deprivation or
excessive loss of fluid.
Water intoxication: kidney failure.
Table 12-1
Page 397
Slide 6
Water sources.
Beverages in the diet.
Water content of food, up to 90%.
Metabolic water.
These 3 sources average 2 1/2 L.
Table 12-2
Page 397
Slide 8
Water losses
Body must excrete 500 ml every
day to discard waste products.
Water lost as vapor from lungs and
sweat from skin; 1/2 of loss.
Some water lost in feces.
Average loss is 2 1/2 L.
Table 12-3
Page 398
Slide 10
Water and blood volume
Water maintains blood volume.
Kidneys regulate blood volume by
releasing or retaining water.
Hypothalamus activates pituitary
gland to secrete ADH to retain
water by kidneys and signal thirst.
Water and blood pressure
Kidneys release enzyme renin
which causes kidneys to reabsorb
sodium; water follows sodium.
Renin activates angiotensin which
constricts blood vessels.
Angiotensin activates aldosterone
which retains more Na+ and water
Water distribution in body.
2/3 inside and 1/3 outside cells.
Mineral salts dissolved in water
become cations (+) or anions (-).
Electrolytes are mineral salts.
Electrolytes attract water and help
to maintain homeostasis.
One Cell and Its Associated Fluids
Fluid between the
cells (intercellular
or interstitial)
Cell
membrane
Nucleus
Fluid within the
cell (intracellular)
Fluid (plasma) within the blood
vessels (intravascular)
Figure 12-1
Page 397
Blood vessel
Slide 14
Electrolyte distribution
Sodium and chloride are outside
the cells.
Potassium, magnesium, sulfate,
phosphate are inside the cells.
Water follows electrolytes across
the cell membranes; osmosis.
Electrolytes must be = in charge.
Table 12-4
Page 402
Slide 16
Osmosis
1 With equal numbers of solute
particles on both sides, the
concentrations are equal,
and the tendency of water to
move in either direction is
about the same.
2 Now additional solute is
added to side B. Solute cannot
flow across the divider (in the
case of a cell, its membrane).23
3 Water can flow both ways
across the divider, but has a
greater tendency to move from
side A to side B, where there
is a greater concentration of
solute. The volume of water
becomes greater on side B,
and the concentrations on
side A and B become equal.
Figure 12-5
Page 403
Slide 17
When sprinkled with salt, vegetables “sweat” because water moves
toward the higher concentration of salt outside the eggplant.
In-text Figure
Page 403
Slide 18
Fluid and Electrolyte imbalance.
Vomiting, diarrhea, profuse
sweating, burns, draining wounds
may cause imbalance.
Sodium and chloride easily lost.
Electrolytes and fluids must be
replaced when imbalance occurs.
Acid-base balance
Normal pH is 7.35 to 7.45 for blood.
Proteins are damaged beyond
normal range; body can’t function.
Buffers in blood, rate of
respiration and regulation by
kidneys maintain acid-base
balance.
The pH Scale
pH’s of common
substances
Basic
14
Concentrated lye
Normal and abnormal
pH ranges of blood
8.00
Death
13
12
11
Alkalosis
Household ammonia
10
pH neutral
9
Baking soda
8
6
Pancreatic juice
Blood
Water
Milk
Urine
5
Coffee
4
Orange juice
3
Vinegar
2
Lemon juice
Gastric juice
7
1
Acidic
0
Battery acid
7.45
Normal
7.35
Acidosis
6.8
Death
Figure 12-6
Page 405
Slide 21
Major minerals
Inorganic elements; can not be
destroyed in food prep.
May be bound by food compounds
or interact with other minerals.
May not be absorbed.
All have upper levels of intake.
Sodium functions
Principal cation and regulator of
volume in extracellular fluid.
Essential for nerve transmission,
muscle contraction, acid-base
balance.
Kidneys filter out excess.
Sodium and health
Need a minimum of 500 mg Na+.
Salt sensitive individuals may
benefit from Na+ restriction.
Hyponatremia: low blood Na+.
Na+ toxicity: edema and Htn.
Processed foods are high in Na+.
What Processing Does to the Sodium and Potassium Contents of Foods
Milks
Meats
Vegetables
Fruits
Grains
Milk (whole)
Roast beef
Fresh corn
Fresh
peaches
Rolled oats
Instant
chocolate
pudding
Chipped beef
Canned,
cream corn
Peach pie
Oat cereal
Unprocessed
Processed
Key:
Potassium
Sodium
Figure 12-8
Page 409
Slide 25
Chloride functions.
Major anion in extracellular fluid.
Part of hydrochloric acid.
Maintains fluid and electrolyte
balance.
Chloride and health
Adequate intake for adults is
2300 mg/day for 19-50 year olds
Need for Cl decreases with age
Deficiency: rare
Toxicity may occur due to
dehydration.
 Processed foods are high in NaCl
Potassium function
Principal cation inside cells.
High intake appears to reduce
high blood pressure.
Potassium and sodium trade
places across cell membranes
during nerve transmission and
muscle contraction.
Potassium and health
Adequate intake for adults is
4700 mg/day.
Best source is fresh fruits and veg.
K+ deficiency is most common
electrolyte imbalance; weakness.
Caused by diuretics, dehydration,
DM acidosis, vomiting, steroids.
Fresh foods, especially fruits
and vegetables, provide
potassium in abundance.
In-text Figure
Page 411
Slide 30
Calcium function
99% is found in bones and teeth.
Cation regulates muscle
contraction, blood clotting, nerve
transmission, secretion of
hormones, activation of enzymes
and regulates blood pressure.
Calcium and health
Recommendations for bone health
1000 mg for 19-50 years old
1200 mg for 50 + years.
Calcium taken from bones when
blood calcium is low.
Phases of Bone Development throughout Life
Peak bone mass
Bone
density
years
Active growth
Bone loss
Figure 12-13
Page 417
Slide 33
Bone Losses over Time Compared
Bone mass
Woman A entered adulthood
with enough calcium in her
bones to last a lifetime.
Danger zone
Woman B had less bone
mass starting out and so
suffered ill effects from
bone loss later on.
Osteoporosis
Age 30
Menopause
Time
Age 60
Figure H12-3
Page 431
Slide 34
Maintaining Blood Calcium from the Diet and from the Bones
With an adequate intake of
calcium-rich food, blood
calcium remains normal...
With a dietary deficiency,
blood calcium still remains
normal...
...and bones deposit
calcium. The result is
strong, dense bones.
...because bones give up
calcium to the blood. The
result is weak, osteoporotic
bones.
Figure 12-11
Page 415
Slide 35
Calcium sources
Milk products, tofu, sardines with
bones, bok choy, black strap
molasses, fortified orange juice,
corn tortillas, broccoli
Milk and milk products are rightly
famous for their calcium contents.
In-text Figure
Page 417
Slide 37
_>50%
absorbed
Cauliflower, watercress,
brussels sprouts, rutabaga,
kale, mustard greens, bok
choy, broccoli, turnip greens
_>30%
absorbed
Milk, calcium-fortified soy
milk, calcium-set tofu,
cheese, yogurt, calcium-fortified
foods and beverages
_>20%
absorbed
Almonds, sesame seeds,
pinto beans, sweet potatoes
_>5%
absorbed
Spinach, rhubarb, Swiss
chard
Bioavailability of Calcium from Selected Foods
In-text Figure
Page 417
Slide 38
Phosphorus function
 Part of bones and teeth
 Found in all body cells; used as a buffer
 Part of DNA and RNA
 Part of ATP, the energy molecule
 Activates enzymes and B vitamins
 Part of phospholipids,
part of cell
membranes, transports other lipids
Phosphorus and health
 RDA: 700 mg per day for adults
 Sources: meats, milk products, legumes,
soda with phosphoric acid
 Dietary deficiency unknown
 High phosphorus, low calcium blood levels
will lead to bone loss in people with kidney
failure.
Magnesium function
 Over half of magnesium is found in the
bones and dental enamel
 Found in muscles and soft tissue
 Necessary for body’s production of protein
and for energy metabolism
 Part of many enzymes
 Inhibits muscle contraction and blood
clotting; calcium promotes these
Magnesium and health
 RDA: 400 mg per day for men
 RDA: 310 mg per day for women
 Sources: legumes, seeds, nuts, leafy green
vegetables
 Deficiency: tetany; impaired central
nervous system function; constricted
circulatory system, may cause Htn
 Toxicity: rare; fatal; from supplements
Sulfur function
 Found in essential nutrients such as
vitamins and amino acids
 Sulfur bonds shape protein molecules and
provide stability to the protein structure
 Skin, hair, nails contain sulfur containing
protein molecules
Sulfur and health
 No RDA for sulfur
 No known deficiency; diet would have to be
deficient in protein rich foods
 Sources: meats, eggs, milk, legumes, nuts
Bacteriophage studies
Click to view
animation.
Animation
Slide 45
A Nephron, One of the Kidney’s Many Functioning Units
A nephron (a working unit of the kidney).
Each kidney contains over one million nephrons.
Blood vessel
Kidney
Glomerulus
1 Blood flows into the glomerulus,
1
Ureter
Pelvis
Bladder
and some of its fluid, with
dissolved substances, is
absorbed into the tubule.
Capillaries
of glomerulus
Tubule
2 Then the fluid and substances
To the body
needed by the body are returned
to the blood in vessels alongside
the tubule.
2
Renal artery
Renal vein
3 The tubule passes waste
materials on to the bladder.
3
To the bladder
Kidney, sectioned
to show location
of nephrons
The cleansing of blood in the nephron is roughly analogous
to the way you might clean your car. First you remove all your
possessions and trash so that the car can be vacuumed.(1)
Then you put back in the car what you want to keep(2) and
throw away the trash. (3)
Figure 12-2
Page 400
Slide 46
How the Body Regulates Blood Volume
Kidneys
Brain
The kidneys respond to
reduced blood flow by
releasing the enzyme
renin.
The hypothalamus responds
to high salt concentrations
in the blood by stimulating
the pituitary gland.
Renin
Renin initiates the activation
of the protein angiotensinogen to angiotensin.
The pituitary gland
releases antidiuretic
hormone (ADH).
Angiotensin
Angiotensin signals
the adrenal gland
to secrete aldosterone.
Angiotensin causes
the blood vessels
to constrict, raising
pressure.
ADH
Aldosterone
Aldosterone and ADH signal the kidneys to retain sodium and water,
respectively, thus increasing blood volume.
Figure 12-3
Page 401
Slide 47
When immersed in water, raisins get plump because water moves
toward the higher concentration of sugar inside the raisins.
In-text Figure
Page 403
Slide 48
Physically active people must remember
to replace their body fluids.
In-text Figure
Page 404
Slide 49
Minerals in a 60-kilogram (132-pound) Human Body
MAJOR MINERALS
The major minerals are those present in amounts
larger than 5 g (a teaspoon). A pound is about
454 g; thus only calcium and phosphorus appear
in amounts larger than a pound.
TRACE MINERALS
There are more than a dozen trace minerals,
although only six are shown here.
Amount (g)
Figure 12-7
Page 406
Slide 50
Fresh herbs add flavor to a recipe
without adding salt.
In-text Figure
Page 408
Slide 51
Potassium in Selected Foods
Food
Serving size (kcalories)
0
200
400
600
Milligrams
800
The AI for potassium is 4700 mg
per day.
POTASSIUM
Fresh fruits (purple), vegetables
(green), legumes (brown), and
meats (red) contribute potassium
to the diet.
Key:
Breads and cereals
Vegetables
Fruits
Milk and milk products
Legumes, nuts, seeds
Meats
Best sources per kcalorie
Figure 12-9
Page 412
Slide 52
Calcium Balance
Rising blood calcium
signals the thyroid
gland to secrete
calcitonin.
Calcitonin
inhibits the
activation
of vitamin D.
Falling blood calcium
Parathyroid
signals the parathyroid
(embedded
glands to secrete
in the thyroid) parathormone.
Thyroid
Calcitonin
Parathormone
Calcitonin
prevents calcium
reabsorption
in the kidneys.
Calcitonin limits
calcium absorption
in the intestines.
Calcitonin inhibits
osteoclast cells
from breaking
down bone,
preventing the
release of calcium.
All these actions lower blood
calcium levels, which inhibits
calcitonin secretion.
Vitamin D
Activation
Vitamin D
Kidneys
Intestines
Bones
Parathormone
stimulates the
activation of
vitamin D.
Vitamin D and
parathormone
stimulate calcium
reabsorption
in the kidneys.
Vitamin D
enhances calcium
absorption in
the intestines.
Vitamin D and
parathormone
stimulate
osteoclast cells to
break down bone,
releasing calcium
into the blood.
All these actions raise blood
calcium levels, which inhibits
parathormone secretion.
Figure 12-10
Page 414
Slide 53
Calcium in Selected Foods
Food
Milligrams
Serving size (kcalories)
CALCIUM
As in the riboflavin figure, milk and milk products
Label(white)
dominate the calcium figure. Most people need at least three
selections from the milk group to meet recommendations.
a Values based on products containing added calcium salts;
the calcium in 1⁄2 c soybeans is about 1⁄3 as much as in
1⁄ c tofu. b If bones are discarded, calcium declines
2
dramatically.
Key:
Breads and cereals
Vegetables
Fruits
Milk and milk products
Legumes, nuts, seeds
Meats
AI for
women
19–50
AI for
women
51+
AI for
men
19–50
AI for
men
51+
Best sources per kcalorie
Figure 12-12
Page 416
Slide 54
Phosphorus in Selected Foods
Food
Milligrams
Serving size (kcalories)
RDA
for
adults
PHOSPHORUS
Protein-rich sources, such as
milk (white), meats (red), and
legumes (brown), provide
abundant phosphorus as well.
Key:
Breads and cereals
Vegetables
Fruits
Milk and milk products
Legumes, nuts, seeds
Meats
Best sources per kcalorie
Figure 12-14
Page 419
Slide 55
Magnesium in Selected Foods
Food
Milligrams
Serving size (kcalories)
RDA for
men
19-30
MAGNESIUM
Legumes (brown) are a rich
source of magnesium.
Key:
Breads and cereals
Vegetables
Fruits
Milk and milk products
Legumes, nuts, seeds
Meats
RDA for
women
19-31
Best sources per kcalorie
Figure 12-15
Page 421
Slide 56
Osteoporosis and
Calcium
In-text Figure
Page 428
Slide 57
Healthy and Osteoporotic Trabecular Bones
Electron micrograph of healthy
trabecular bone.
Electron micrograph of trabecular bone
affected by osteoporosis.
Figure H12-1
Page 429
Slide 58
Loss of Height in a Woman Caused by Osteoporosis
6 inches lost
50 years old
80 years old
Figure H12-2
Page 430
Slide 59
Table H12-1
Page 430
Slide 60
Table H12-2
Page 430
Slide 61
Strength training helps to
build strong bones.
In-text Figure
Page 432
Slide 62