Download Nerve activates contraction

Nutrition
 Nutrient—substance used by the body for growth,
maintenance, and repair
 Nutrition-the study of the effects of substances in
food on the body and health
 Malnutrition- not enough of the right nutrients
 Starvation-not enough food
 Calorie- the amount of energy needed to raise one
gram of water 1 degree Celsius
 Use bomb calorimeter
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Nutrition
 Hunger- unpleasant feeling from lack of food
 Satiety- the stomach being full to the point of
satisfaction
 Takes 20 minutes to reach brain
 Appetite- the desire of food and the pleasure
eating provides
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Nutrition
 Major nutrients
 Carbohydrates
 Lipids
 Proteins
 Water
 Minor nutrients
 Vitamins
 Minerals
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Five Basic Food Groups and
Some of Their Major Nutrients
Table 14.2 (1 of 2)
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Five Basic Food Groups and
Some of Their Major Nutrients
Table 14.2 (2 of 2)
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
USDA Food Guide Pyramid
Figure 14.17
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Energy sources
 Carbohydrates (CHO’s) -4 calories
 Proteins- 4 calories
 Fats- 9 calories
 Alcohol- 7 calories
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Dietary Sources of Major Nutrients
 Carbohydrates
 What types of foods are carbohydrates?
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Dietary Sources of Major Nutrients
 Carbohydrates
 Most are derived from plants
 Exceptions: lactose from milk and small
amounts of glycogens from meats
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Carbohydrates
 4 types
 Monosaccharide
 Glucose (sugar in blood) & fructose
 Disaccharide
 Two sugars hooked together
 Table sugar and lactose
 Complex CHO’s or polysaccharides
 3 or more
 Glycogen and starch
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Carbohydrates
 Cellulose- Dietary Fiber or Roughage
 Body can’t break these down and digest
them
 Reduces the rate of colorectal cancer
 Insoluble
 Does not dissolve in water
 Wheat, bran, whole grains,
vegetables
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Carbohydrates
 Soluble
 Dissolves in water and forms gel
that picks up substances and
carries it out of the body
 Oats, beans, barley
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Lactose Intolerant
 Lack the enzyme lactase to digest lactose
 Symptoms: bloating, gas, cramps, diarrhea
 Lactaid is OTC product to help break it down
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Diabetes Mellitus
 Little or no insulin produced by islet cells on
pancreas
 Insulin is what allows glucose into the cell so
it can get energy
 Two types of Diabetes
 Insulin-dependent or Juvenile Onset
 Non-Insulin Dependent or Adult Onset
 Most common
 Sometimes controlled by diet
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Diabetes Mellitus
 Hyperglycemia
 High glucose level
 Hypoglycemia
 Low blood sugar
 Brain is starving and can lead to coma
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Dietary Treatment of Diabetes
 Achieve and maintain desirable body weight
 Eat a balanced diet
 No sugars
 Eat 3 meals and 3 snacks a day
 Eat at regular times
 Regular pattern of exercise to regulate glucose
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Complications of Diabetes
 Slow healing of cuts and bruises
 Kidney problems
 Blindness
 Neuropathy
 More risk of heart disease
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Dietary Sources of Major Nutrients
 Lipids
 Saturated fats from animal products
 Unsaturated fats from nuts, seeds, and
vegetable oils
 Cholesterol from egg yolk, meats, and milk
products
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Functions of Fat
 Source of stored energy
 Protects our organs
 Body insulation
 Part of all cell membranes (phospholipids)
 Needed to make hormones
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
How The Body Uses Fats
 Needed to digest fat soluble vitamins- A,D,E,K
 Provides essential nutrients
 Provides flavor for food
 Provides satiety
 Spares protein from use for energy
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Structures of Fats
 Triglyceride- glycerol with 3 fatty acids
 Diglyceride- glycerol with 2 fatty acids
 Monoglycerol- one fatty acid
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Saturated Vs. Unsaturated Fats
Saturated
 Solid at room
temperature
Unsaturated
 Liquid at room
temperature
 Stores well
 Becomes rancid easily
 Fat on meat
 Vegetable oil
 Butter
 Palm and coconut oil
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Types of Fats
 Saturated Fats have all of the hydrogen bonds full
and are not good for you
 Polyunsaturated fats won’t help or hurt you
 Monounsaturated fats will help you
 Artificial Fats- Olestra
 Can cause some digestive tract discomfort
and should be used sparingly
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Cholesterol
 Should be under 200 mg
 LDL’s – low density lipoproteins and put you at
greater risk for arteriosclerosis, blood clots, heart
attacks, and strokes
 HDL’s- high density lipoproteins and are good for
you
 To lower LDL’s
 Be female
 Stop smoking and limit caffeine
 Exercise
 Increase Omega 3 intake and eat more oatmeal
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Ketosis
 When the body starts using protein for energy
due to lack of fat
 Common in athletes that try and lose too
much weight
 Characterized by fruit oder to breath
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Dietary Sources of Major Nutrients
 Proteins
 Complete proteins—contain all essential
amino acids
 Most are from animal products
 Legumes and beans also have proteins, but
are incomplete
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Proteins
 Amino acids are the building blocks of proteins
 9 essential amino acids that must come from diet
because the body can’t make them
 Nonessential amino acids- body can make
 Complete proteins- have all essential amino acids
 Meat, cheese, eggs
 Incomplete proteins- do not have all essential
amino acids
 Beans, corn, peanut butter
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Proteins
 Complimentary Proteins Combine 2 or more incomplete proteins to
make a complete protein
 Bread and peanut butter
 Recommended protein intake is .8 grams per
pound of body weight
 Kwashiokor- enough calories, but not enough
protein
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Problems Associated With Lack of Protein
 Can’t make digestive enzymes
 Can’t make anibodies
 Some hormones not produced in large enough
amounts, like insulin
 Nerve impulses not sent, apathy
 Hair color loss
 Wounds won’t heal
 Muscle tissue breaks down
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Vegetarianism
 Why?
 Ethics about killing animals
 Religious beliefs
 Concern about drugs in meat
 Concern about cholesterol and saturated fat
 Expense of meat
 Some don’t like the taste
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Types of Vegetarians
 Vegan- eat only plant foods
 Have the most nutritional concerns
 Lacto vegans- will eat dairy products
 Lacto-ovo-vegans- include dairy and eggs
 Lacto-ovo-pesco-vegans- include dairy, eggs, and
fish
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Nutritional Concerns of Vegetarian Diets
 B 12
 Only found in animal products
 Must take supplements
 Iron
 Best source is red meat
 Calcium
 May need supplements or fortified foods like
butter and orange juice
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Health Advantages of Vegetarian Diets
 Lower body weight
 Lower blood cholesterol
 Lower rates of breast and colon cancer
 Better digestive health due to higher fiber diet
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Dietary Sources of Major Nutrients
 Vitamins
 Most vitamins are used as coenzymes
 Found in all major food groups
 Needed in small quantities
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Vitamins
 Fat soluble vitamins (A,D,E,K) can be stored
 Water soluble vitamins like vitamin C can’t be
stored and must continually be supplied
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Vitamins
 Folacin or Folic Acid
 Found in dark green leafy vegetables
 Deficiency causes aplastic anemia
 Also important in pregnant women to prevent
spina bifida
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Vitamins
 Vitamin C
 Deficiency is called scurvy
 Stop making collagen
 Weakened blood vessels
 Loss of hair
 Internal bleeding
 In large doses it may prevent colds
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Vitamins
 Vitamin D
 Increases Calcium absorption
 Deficiency is called rickets
 Bones are soft and legs are bowed
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Vitamins
 Have an RDA- recommended dietary allowance
 To preserve vitamin and mineral content
 Store in cool dark place
 eat peelings whenever possible
 Cook in small amounts of water and steam if
possible
 Heat destroys many vitamins and minerals
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Vitamins
 Enrichment- replace vitamins that were originally in
the food, but may have been loss during processing
 Fortification- add vitamins and minerals that weren’t
originally in the product
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Dietary Sources of Major Nutrients
 Minerals
 Play many roles in the body
 Most mineral-rich foods are vegetables,
legumes, milk, and some meats
 Many are required for nerve conduction and
contraction of muscle fibers
 Major minerals- need in amounts greater than
100 mg a day
 Minor minerals- needed only in small amounts
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Minerals
 Calcium
 Needed for bone strength, blood clotting,
muscle contraction, and nerve impulse
transmission
 Deficiency causes osteoporosis
 Found in dairy products and some vegetables
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Minerals
 Iron
 Transport oxygen and carbon dioxide in
hemoglobin
 Deficiency is called anemia
 Toxicity- can lead to death if overdose
 Found mainly in red meat
 If taken with vitamin C it will be absorbed
better by the body
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Minerals
 Iodine
 Helps regulate metabolism and determine rate
of thyroid
 Deficiency can lead to a goiter
 Cretinism- named for the island of Crete
 Goiter Belt- geographic area where soil is low
in iodine
 We now iodize salt to prevent deficiency
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Minerals
 Flouride
 Reduces tooth decay
 Toxicity- rust colored stains on teeth
 Sources: fluoridated water, toothpaste, and
mouthwash
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Water
 Body is 70-75% water
 Functions of Water
 Place for chemical reactions
 Maintain acid/base balance
 Nutrient and waste transport
 Regulation of temperature
 Lubrication and shock absorbancy
 Hard water contains high levels of calcium,
magnesium, and iron
 Soft water- minerals replaced with salt
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Nutrition and the Cancer Patient
 Many cancer patients lose weight
 Loss of appetite
 High energy demands of tumor
 Nutrition and maintaining weight is very important
 Those who have not lost weight live twice as
long
 Chemotherapy is more effective if weight can
be maintained
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Diet and Prevention of Cancer
 Reduce fat to 30% or less to reduce risk of breast
and colon cancer
 Increase fiber
 Increase vitamin A and C
 Reduce processed meats
 Salt-cured, pickled and smoked meats
 Reduce alcohol
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Metabolism
 Chemical reactions necessary to maintain life
 Catabolism—substances are broken down to
simpler substances; energy is released
 Anabolism—larger molecules are built from
smaller ones
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Carbohydrate Metabolism
 Carbohydrates are the body’s preferred source to
produce cellular energy (ATP)
 Glucose (blood sugar) is the major breakdown
product and fuel to make ATP
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Cellular Respiration
 Oxygen-using events take place within the cell to
create ATP from ADP
 Carbon leaves cells as carbon dioxide (CO2)
 Hydrogen atoms are combined with oxygen to
form water
 Energy produced by these reactions adds a
phosphorus to ADP to produce ATP
 ATP can be broken down to release energy for
cellular use
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Carbohydrate Metabolism
Figure 14.18
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Metabolic Pathways Involved in
Cellular Respiration
 Glycolysis—energizes a glucose molecule so it
can be split into two pyruvic acid molecules and
yield ATP
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Cellular Respiration
Chemical energy (high-energy electrons)
CO2
CO2
Glycolysis
Glucose
Cytosol
of cell
Pyruvic
acid
Mitochondrion
Chemical energy
Krebs
cycle
Electron transport
chain and oxidative
phosphorylation
H2O
Mitochondrial
cristae
Via oxidative
phosphorylation
ATP
ATP
ATP
Figure 14.19
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Cellular Respiration
Chemical energy (high-energy electrons)
Mitochondrion
Glycolysis
Glucose
Cytosol
of cell
Pyruvic
acid
Mitochondrial
cristae
ATP
Figure 14.19, step 1
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Cellular Respiration
Chemical energy (high-energy electrons)
CO2
CO2
Glycolysis
Glucose
Cytosol
of cell
ATP
Pyruvic
acid
Mitochondrion
Chemical energy
Krebs
cycle
Mitochondrial
cristae
ATP
Figure 14.19, step 2
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Cellular Respiration
Chemical energy (high-energy electrons)
CO2
CO2
Glycolysis
Glucose
Cytosol
of cell
Pyruvic
acid
Mitochondrion
Chemical energy
Krebs
cycle
Electron transport
chain and oxidative
phosphorylation
H2O
Mitochondrial
cristae
Via oxidative
phosphorylation
ATP
ATP
ATP
Figure 14.19, step 3
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Metabolic Pathways Involved in
Cellular Respiration
 Krebs cycle
 Produces virtually all the carbon dioxide and
water resulting from cell respiration
 Yields a small amount of ATP
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Cellular Respiration
Chemical energy (high-energy electrons)
CO2
CO2
Glycolysis
Glucose
Cytosol
of cell
Pyruvic
acid
Mitochondrion
Chemical energy
Krebs
cycle
Electron transport
chain and oxidative
phosphorylation
H2O
Mitochondrial
cristae
Via oxidative
phosphorylation
ATP
ATP
ATP
Figure 14.19
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Metabolic Pathways Involved in
Cellular Respiration
 Electron transport chain
 Hydrogen atoms removed during glycolysis
and the Krebs cycle are delivered to protein
carriers
 Hydrogen is split into hydrogen ions and
electrons in the mitochondria
 Electrons give off energy in a series of steps
to enable the production of ATP
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Cellular Respiration
Chemical energy (high-energy electrons)
CO2
CO2
Glycolysis
Glucose
Cytosol
of cell
Pyruvic
acid
Mitochondrion
Chemical energy
Krebs
cycle
Electron transport
chain and oxidative
phosphorylation
H2O
Mitochondrial
cristae
Via oxidative
phosphorylation
ATP
ATP
ATP
Figure 14.19
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Metabolic Pathways Involved in
Cellular Respiration
Figure 14.20a
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Metabolism of Carbohydrates
 Hyperglycemia—excessively high levels of
glucose in the blood
 Excess glucose is stored in body cells as
glycogen
 If blood glucose levels are still too high, excesses
are converted to fat
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Metabolism of Carbohydrates
Figure 14.21a
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Metabolism of Carbohydrates
 Hypoglycemia—low levels of glucose in the blood
 Liver breaks down stored glycogen and releases
glucose into the blood
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Fat Metabolism
 Handled mostly by the liver
 Uses some fats to make ATP
 Synthesizes lipoproteins, thromboplastin, and
cholesterol
 Releases breakdown products to the blood
 Body cells remove fat and cholesterol to build
membranes and steroid hormones
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Use of Fats for ATP Synthesis
 Fats must first be broken down to acetic acid
 Within mitochondria, acetic acid is completely
oxidized to produce water, carbon dioxide, and
ATP
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
ATP Formation
Figure 14.21d
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Fat Metabolism
 Acidosis (ketoacidosis) results from incomplete
fat oxidation in which acetoacetic acid and
acetone accumulate in the blood
 Breath has a fruity odor
 Common with
 “No carbohydrate” diets
 Uncontrolled diabetes mellitus
 Starvation
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Fat Metabolism
Figure 14.21b
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Protein Metabolism
 Proteins are conserved by body cells because
they are used for most cellular structures
 Ingested proteins are broken down to amino acids
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Protein Metabolism
 Cells remove amino acids to build proteins
 Synthesized proteins are actively transported
across cell membranes
 Amino acids are used to make ATP only when
proteins are overabundant or there is a shortage
of other sources
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Production of ATP from Protein
 Amine groups are removed from proteins as
ammonia
 The rest of the protein molecule enters the Krebs
cycle in mitochondria
 The liver converts harmful ammonia to urea which
can be eliminated in urine
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Protein Metabolism
Figure 14.21c
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Role of the Liver in Metabolism
 Several roles in digestion
 Manufactures bile
 Detoxifies drugs and alcohol
 Degrades hormones
 Produces cholesterol, blood proteins (albumin
and clotting proteins)
 Plays a central role in metabolism
 Can regenerate if part of it is damaged or removed
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Metabolic Functions of the Liver
 Glycogenesis—“glycogen formation”
 Glucose molecules are converted to glycogen
 Glycogen molecules are stored in the liver
 Glycogenolysis—“glucose splitting”
 Glucose is released from the liver after
conversion from glycogen
 Gluconeogenesis—“formation of new sugar”
 Glucose is produced from fats and proteins
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Metabolic Functions of the Liver
Figure 14.22
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Metabolic Functions of the Liver
 Fats and fatty acids are picked up by the liver
 Some are oxidized to provide energy for liver
cells
 The rest are broken down into simpler
compounds and released into the blood
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Cholesterol Metabolism
 Cholesterol is not used to make ATP
 Functions of cholesterol
 Serves as a structural basis of steroid
hormones and vitamin D
 Is a major building block of plasma
membranes
 Most cholesterol is produced in the liver (85%)
and is not from diet (15%)
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Cholesterol Transport
 Cholesterol and fatty acids cannot freely circulate
in the bloodstream
 They are transported by lipoproteins (lipid-protein
complexes)
 Low-density lipoproteins (LDLs) transport to
body cells
 Rated “bad lipoproteins” since they can
lead to artherosclerosis
 High-density lipoproteins (HDLs) transport
from body cells to the liver
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Body Energy Balance
 Energy intake = total energy output
 (heat + work + energy storage)
 Energy intake is liberated during food
oxidation
 Energy output
 Heat is usually about 60%
 Storage energy is in the form of fat or
glycogen
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Regulation of Food Intake
 Body weight is usually relatively stable
 Energy intake and output remain about equal
 Mechanisms that may regulate food intake
 Levels of nutrients in the blood
 Hormones
 Body temperature
 Psychological factors
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Metabolic Rate and Body Heat Production
 Basic metabolic rate (BMR)—amount of heat
produced by the body per unit of time at rest
 Average BMR is about 60 to 72 kcal/hour
 Kilocalorie (kcal) is the unit of measure for the
energy value of foods and the amount of energy
used by the body
 3,500 calories equals one pound
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Metabolic Rate and Body Heat Production
 Factors that influence BMR
 Surface area—a small body usually has a
higher BMR
 Gender—males tend to have higher BMRs
 Age—children and adolescents have higher
BMRs
 The amount of thyroxine produced is the most
important control factor
 More thyroxine means a higher metabolic
rate
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Factors Determining BMR
Table 14.3
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Total Metabolic Rate (TMR)
 Total amount of kilocalories the body must
consume to fuel ongoing activities
 TMR increases with an increase in body activity
 TMR must equal calories consumed to maintain
homeostasis and maintain a constant weight
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Body Temperature Regulation
 Most energy is released as foods are oxidized
 Most energy escapes as heat
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Body Temperature Regulation
 The body has a narrow range of homeostatic
temperature
 Must remain between 35.6°C to 37.8°C
(96°F to 100°F)
 The body’s thermostat is in the hypothalamus
 Initiates heat-loss or heat-promoting
mechanisms
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Body Temperature Regulation
 Heat-promoting mechanisms
 Vasoconstriction of blood vessels
 Blood is rerouted to deeper, more vital
body organs
 Shivering—contraction of muscles produces
heat
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Body Temperature Regulation
 Heat-loss mechanisms
 Heat loss from the skin via radiation and
evaporation
 Skin blood vessels and capillaries are
flushed with warm blood
 Evaporation of perspiration cools the skin
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Mechanisms of Body Temperature Regulation
Skin blood vessels
dilate: Capillaries
become flushed with
warm blood; heat
radiates from
skin surface
Sweat glands activated:
Secrete perspiration, which
is vaporized by body heat,
helping to cool the body
Activates
heat-loss center
in hypothalamus
Body temperature decreases:
Blood temperature
declines and hypothalamus heat-loss
center “shuts off”
Blood warmer
than
hypothalamic
set point
Stimulus:
Increased body
temperature
(e.g., when
exercising or the
climate is hot)
Homeostasis = normal body
temperature (35.6°C–37.8°C)
Stimulus:
Decreased body
temperature
(e.g., due to cold
environmental
temperatures)
Blood cooler than
hypothalamic set point
Body temperature increases:
Blood temperature
rises and hypothalamus heat-promoting
center “shuts off”
Skin blood vessels constrict:
Blood is diverted from skin
capillaries and withdrawn to
deeper tissues; minimizes
overall heat loss
from skin surface
Activates heatpromoting center
in hypothalamus
Skeletal muscles
activated when more
heat must be generated;
shivering begins
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 14.23
Mechanisms of Body Temperature Regulation
Stimulus:
Increased body
temperature
(e.g., when
exercising or the
climate is hot)
Homeostasis = normal body
temperature (35.6°C–37.8°C)
Figure 14.23, step 1
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Mechanisms of Body Temperature Regulation
Activates
heat-loss center
in hypothalamus
Blood warmer
than hypothalamic
set point
Stimulus:
Increased body
temperature
(e.g., when
exercising or the
climate is hot)
Homeostasis = normal body
temperature (35.6°C–37.8°C)
Figure 14.23, step 2
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Mechanisms of Body Temperature Regulation
Skin blood vessels
dilate: Capillaries
become flushed with
warm blood; heat
radiates from
skin surface
Activates
heat-loss center
in hypothalamus
Blood warmer
than hypothalamic
set point
Stimulus:
Increased body
temperature
(e.g., when
exercising or the
climate is hot)
Homeostasis = normal body
temperature (35.6°C–37.8°C)
Figure 14.23, step 3
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Mechanisms of Body Temperature Regulation
Skin blood vessels
dilate: Capillaries
become flushed with
warm blood; heat
radiates from
skin surface
Activates
heat-loss center
in hypothalamus
Sweat glands activated:
Secrete perspiration, which
is vaporized by body heat,
helping to cool the body
Blood warmer
than hypothalamic
set point
Stimulus:
Increased body
temperature
(e.g., when
exercising or the
climate is hot)
Homeostasis = normal body
temperature (35.6°C–37.8°C)
Figure 14.23, step 4
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Mechanisms of Body Temperature Regulation
Skin blood vessels
dilate: Capillaries
become flushed with
warm blood; heat
radiates from
skin surface
Activates
heat-loss center
in hypothalamus
Sweat glands activated:
Secrete perspiration, which
is vaporized by body heat,
helping to cool the body
Body temperature decreases:
Blood temperature
declines and hypothalamus heat-loss
center “shuts off”
Blood warmer
than hypothalamic
set point
Stimulus:
Increased body
temperature
(e.g., when
exercising or the
climate is hot)
Homeostasis = normal body
temperature (35.6°C–37.8°C)
Figure 14.23, step 5
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Mechanisms of Body Temperature Regulation
Skin blood vessels
dilate: Capillaries
become flushed with
warm blood; heat
radiates from
skin surface
Activates
heat-loss center
in hypothalamus
Sweat glands activated:
Secrete perspiration, which
is vaporized by body heat,
helping to cool the body
Body temperature decreases:
Blood temperature
declines and hypothalamus heat-loss
center “shuts off”
Blood warmer
than hypothalamic
set point
Stimulus:
Increased body
temperature
(e.g., when
exercising or the
climate is hot)
Homeostasis = normal body
temperature (35.6°C–37.8°C)
Figure 14.23, step 6
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Mechanisms of Body Temperature Regulation
Homeostasis = normal body
temperature (35.6°C–37.8°C)
Stimulus:
Decreased body
temperature
(e.g., due to cold
environmental
temperatures)
Figure 14.23, step 7
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Mechanisms of Body Temperature Regulation
Homeostasis = normal body
temperature (35.6°C–37.8°C)
Stimulus:
Decreased body
temperature
(e.g., due to cold
environmental
temperatures)
Blood cooler than
hypothalamic set point
Activates heatpromoting center
in hypothalamus
Figure 14.23, step 8
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Mechanisms of Body Temperature Regulation
Homeostasis = normal body
temperature (35.6°C–37.8°C)
Stimulus:
Decreased body
temperature
(e.g., due to cold
environmental
temperatures)
Blood cooler than
hypothalamic set point
Activates heatpromoting center
in hypothalamus
Skeletal muscles
activated when more
heat must be generated;
shivering begins
Figure 14.23, step 9
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Mechanisms of Body Temperature Regulation
Homeostasis = normal body
temperature (35.6°C–37.8°C)
Stimulus:
Decreased body
temperature
(e.g., due to cold
environmental
temperatures)
Blood cooler than
hypothalamic set point
Skin blood vessels constrict:
Blood is diverted from skin
capillaries and withdrawn to
deeper tissues; minimizes
overall heat loss
from skin surface
Activates heatpromoting center
in hypothalamus
Skeletal muscles
activated when more
heat must be generated;
shivering begins
Figure 14.23, step 10
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Mechanisms of Body Temperature Regulation
Homeostasis = normal body
temperature (35.6°C–37.8°C)
Stimulus:
Decreased body
temperature
(e.g., due to cold
environmental
temperatures)
Blood cooler than
hypothalamic set point
Body temperature increases:
Blood temperature
rises and hypothalamus heat-promoting
center “shuts off”
Skin blood vessels constrict:
Blood is diverted from skin
capillaries and withdrawn to
deeper tissues; minimizes
overall heat loss
from skin surface
Activates heatpromoting center
in hypothalamus
Skeletal muscles
activated when more
heat must be generated;
shivering begins
Figure 14.23, step 11
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Mechanisms of Body Temperature Regulation
Homeostasis = normal body
temperature (35.6°C–37.8°C)
Stimulus:
Decreased body
temperature
(e.g., due to cold
environmental
temperatures)
Blood cooler than
hypothalamic set point
Body temperature increases:
Blood temperature
rises and hypothalamus heat-promoting
center “shuts off”
Skin blood vessels constrict:
Blood is diverted from skin
capillaries and withdrawn to
deeper tissues; minimizes
overall heat loss
from skin surface
Activates heatpromoting center
in hypothalamus
Skeletal muscles
activated when more
heat must be generated;
shivering begins
Figure 14.23, step 12
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Mechanisms of Body Temperature Regulation
Skin blood vessels
dilate: Capillaries
become flushed with
warm blood; heat
radiates from
skin surface
Sweat glands activated:
Secrete perspiration, which
is vaporized by body heat,
helping to cool the body
Activates
heat-loss center
in hypothalamus
Body temperature decreases:
Blood temperature
declines and hypothalamus heat-loss
center “shuts off”
Blood warmer
than
hypothalamic
set point
Stimulus:
Increased body
temperature
(e.g., when
exercising or the
climate is hot)
Homeostasis = normal body
temperature (35.6°C–37.8°C)
Stimulus:
Decreased body
temperature
(e.g., due to cold
environmental
temperatures)
Blood cooler than
hypothalamic set point
Body temperature increases:
Blood temperature
rises and hypothalamus heat-promoting
center “shuts off”
Skin blood vessels constrict:
Blood is diverted from skin
capillaries and withdrawn to
deeper tissues; minimizes
overall heat loss
from skin surface
Activates heatpromoting center
in hypothalamus
Skeletal muscles
activated when more
heat must be generated;
shivering begins
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 14.23, step 13
Body Temperature Regulation
 Fever—controlled hyperthermia
 Results from infection, cancer, allergic
reactions, CNS injuries
 If the body thermostat is set too high, body
proteins may be denatured and permanent
brain damage may occur
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Developmental Aspects of the Digestive System
 The alimentary canal is a continuous tube by the
fifth week of development
 Digestive glands bud from the mucosa of the
alimentary tube
 The developing fetus receives all nutrients
through the placenta
 In newborns, feeding must be frequent, peristalsis
is inefficient, and vomiting is common
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Developmental Aspects of the Digestive System
 Newborn reflexes
 Rooting reflex helps the infant find the nipple
 Sucking reflex helps the infant hold on to the
nipple and swallow
 Teething begins around age six months
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Developmental Aspects of the Digestive System
 Problems of the digestive system
 Gastroenteritis—inflammation of the
gastrointestinal tract
 Appendicitis—inflammation of the appendix
 Metabolism decreases with old age
 Middle-age digestive problems
 Ulcers
 Gallbladder problems
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Developmental Aspects of the Digestive System
 Activity of the digestive tract in old age
 Fewer digestive juices
 Peristalsis slows
 Diverticulosis and cancer are more common
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings