Unit 1: What is Biology?
Unit 2: Ecology
Unit 3: The Life of a Cell
Unit 4: Genetics
Unit 5: Change Through Time
Unit 6: Viruses, Bacteria, Protists, and Fungi
Unit 7: Plants
Unit 8: Invertebrates
Unit 9: Vertebrates
Unit 10: The Human Body
Unit 1: What is Biology?
Chapter 1: Biology: The Study of Life
Unit 2: Ecology
Chapter 2: Principles of Ecology
Chapter 3: Communities and Biomes
Chapter 4: Population Biology
Chapter 5: Biological Diversity and Conservation
Unit 3: The Life of a Cell
Chapter 6: The Chemistry of Life
Chapter 7: A View of the Cell
Chapter 8: Cellular Transport and the Cell Cycle
Chapter 9: Energy in a Cell
Unit 4: Genetics
Chapter 10: Mendel and Meiosis
Chapter 11: DNA and Genes
Chapter 12: Patterns of Heredity and Human Genetics
Chapter 13: Genetic Technology
Unit 5: Change Through Time
Chapter 14: The History of Life
Chapter 15: The Theory of Evolution
Chapter 16: Primate Evolution
Chapter 17: Organizing Life’s Diversity
Unit 6: Viruses, Bacteria, Protists, and Fungi
Chapter 18: Viruses and Bacteria
Chapter 19: Protists
Chapter 20: Fungi
Unit 7: Plants
Chapter 21:
Chapter 22:
Chapter 23:
Chapter 24:
What Is a Plant?
The Diversity of Plants
Plant Structure and Function
Reproduction in Plants
Unit 8: Invertebrates
Chapter 25: What Is an Animal?
Chapter 26: Sponges, Cnidarians, Flatworms, and
Roundworms
Chapter 27: Mollusks and Segmented Worms
Chapter 28: Arthropods
Chapter 29: Echinoderms and Invertebrate
Chordates
Unit 9: Vertebrates
Chapter 30: Fishes and Amphibians
Chapter 31: Reptiles and Birds
Chapter 32: Mammals
Chapter 33: Animal Behavior
Unit 10: The Human Body
Chapter 34: Protection, Support, and Locomotion
Chapter 35: The Digestive and Endocrine Systems
Chapter 36: The Nervous System
Chapter 37: Respiration, Circulation, and Excretion
Chapter 38: Reproduction and Development
Chapter 39: Immunity from Disease
The Human Body
Protection, Support, and Locomotion
The Digestive and Endocrine System
The Nervous System
Respiration, Circulation, and Excretion
Reproduction and Development
Immunity from Disease
Chapter 34 Protection, Support, and Locomotion
34.1: Skin: The Body’s Protection
34.1: Section Check
34.2: Bones: The Body’s Support
34.2: Section Check
34.3: Muscles for Locomotion
34.3: Section Check
Chapter 34 Summary
Chapter 34 Assessment
Chapter 32
What You’ll Learn
You will interpret the structure and
functions of the integumentary system.
You will identify the functions of the
skeletal system.
You will classify the different types
of muscles in the body.
32.1
Section Objectives:
• Compare the structures and functions
of the epidermis and dermis.
• Identify the role of the skin in responding
to external stimuli.
• Outline the healing process that takes
place when the skin is injured.
32.1
Structure and Functions of
the Integumentary System
• Skin, the main organ of the integumentary (inh
TE gyuh MEN tuh ree) system, is composed of
layers of the four types of body tissues:
epithelial, connective, muscle, and nervous.
• Epithelial tissue, found
in the outer layer of the
skin, functions to cover
surfaces of the body.
32.1
Structure and Functions of
the Integumentary System
• Connective tissue, which consists of both
tough and flexible protein fibers, serves as a
sort of organic glue, holding your body
together.
• Muscle tissues moves parts of the body. In
the skin, muscle interacts with hairs on the
skin to respond to stimuli, such as cold and
fright.
32.1
Structure and Functions of
the Integumentary System
• Nervous tissue helps us detect external stimuli,
such as pain or pressure.
Epidermis
Dermis
32.1
Structure and Functions of
the Integumentary System
• Skin is composed of two principal layers—the
epidermis and dermis.
Epidermis
Dermis
32.1
Epidermis: The outer thinner layer of skin
32.1
Epidermis: The outer thinner layer of skin
• The top layer of cells, although dead &
flattened, serves an important function as they
contain a protein called keratin (KER uh tun).
• Keratin helps to waterproof and protect the
living cell layers underneath from exposure to
bacteria, heat, and chemicals.
32.1
Epidermis: The outer thinner layer of skin
• The interior layer of the epidermis contains
living cells that continually divide by mitosis to
replace the dead cells.
• Some of these cells contain melanin, a pigment
that colors the skin and helps protect body cells
from damage by solar radiation. Even though the #
of melanin-producing cells is about the same in
each person, the amt. of melanin produced per cell
varies, resulting in different colors of skin.
• Every four weeks, all cells of the epidermis are
replaced by new cells.
32.1
Epidermis: The outer thinner layer of skin
• The epidermis on the
fingers and palms of your
hands, and on the toes and
soles of your feet, contain
ridges and grooves that are
formed before birth.
• These epidermal ridges are
important for gripping as
they increase friction.
32.1
Dermis: The inner thicker layer of skin
The
thickness of
this layer
varies
depending
on the
function of
that body
part.
32.1
The Skin
The fat
layer is
below the
dermis. It
functions
to store E,
provide
insulation,
& acts a
shock
absorber.
Oil glands
Hair
Sweat
glands
32.1
Functions of the integumentary system
• Primary function is PROTECTION
• One function of skin is to help maintain
homeostasis by regulating your internal body
temperature.
• Erector pili muscle & goose bumps – forma a
layer of insulation to prevent heat loss.
• When your body temperature rises, the many
small blood vessels in the dermis dilate, blood
flow increases, and body heat is lost by
radiation.
32.1
Functions of the integumentary system
• When you are cold, the blood vessels in
the skin constrict and heat is conserved.
• Glands in the dermis produce
sweat in response to an
increase in body temperature.
• As sweat evaporates, water
changes state from liquid to
vapor and heat is lost.
32.1
Functions of the integumentary system
3 functions of the oil produced by
the skin:
• Keeps the hair moist
• Keeps the skin soft & pliable
• Inhibits the growth of some bacteria
32.1
Functions of the integumentary system
• Skin also functions as a sense organ.
• Nerve cells in the dermis receive stimuli
from the external environment and relay
information about pressure, pain, and
temperature to the brain.
32.1
Functions of the integumentary system
• Another function of the skin is to maintain a
chemical balance of certain substances, such
as Vitamin D.
• When exposed to ultraviolet light, skin cells
produce vitamin D, a nutrient that aids the
absorption of calcium into the bloodstream.
32.1
Functions of the integumentary system
• Cuts or other openings in the skin surface
allow bacteria to enter the body, so they
must be repaired quickly.
32.1
Skin Injury and Healing
• When the epidermis sustains a mild injury,
such as a scrape, the deepest layer of
epidermal cells divide to help fill in the gap
left by the abrasion.
• If, however, the injury extends into the dermis,
where blood vessels are found, bleeding
usually occurs.
32.1
32.1
Skin Injury and Healing
• Burns can result from exposure to the sun
or contact with chemicals or hot objects.
• Burns are rated according to their severity.
32.1
Skin Injury and Healing
• First-degree burns, such as
a mild sunburn, involve the
death of epidermal cells
and are characterized by
redness and mild pain.
• First-degree burns usually
heal in about one week
without leaving a scar.
32.1
Skin Injury and Healing
• Second-degree burns involve damage to skin
cells of both the epidermis and the dermis and
can result in blistering and scarring.
• The most severe burns are third-degree burns,
which destroy both the epidermis and the
dermis.
• With this type of burn, skin function is
lost, and skin grafts may be required to
replace lost skin.
32.1
Skin Injury and Healing
• As people get older,
their skin changes.
• It becomes drier as
glands decrease their
production of lubricating
skin oils—a mixture of
fats, cholesterol, proteins,
and inorganic salts.
32.1
Skin Injury and Healing
• Wrinkles may appear
as the elasticity of the
skin decreases.
32.1
Question 1
What part of the skin responds to external
stimuli such as heat and pressure?
A. epithelial tissue
B. nervous tissue
C. connective tissue
D. muscle tissue
32.1
The answer is B, nervous tissue.
Nerve endings
32.1
Question 2
Why is your skin considered an organ?
Answer
Skin is composed of cells and tissues. A group
of tissues that work together to perform a
specialized function are called an organ.
32.1
Question 3
The thicker portion of skin that is composed
of blood vessels, nerves, nerve endings, hair
follicles, sweat glands, and oil glands is
called the _______.
A.
B.
C.
D.
dermis
subcutaneous layer
epidermis
fat tissue
32.1
The answer is A, dermis.
32.2
Section Objectives
• Compare the different types of
movable joints.
• Describe how bone is formed.
• Identify the structure and functions
of the skeletal system.
32.2
Skeletal
System
Structure
• The adult human
skeleton contains
about 206 bones.
• Its two main parts
are shown.
32.2
Skeletal
System
Structure
32.2
Joints: Where bones meet
• In vertebrates, joints are found where two or
more bones meet.
• Most joints facilitate the movement of bones
in relation to one another.
• The joints of the skull, on the other hand, are
fixed joints, as the bones of the skull don’t
move.
32.2
32.2
Joints: Where bones meet
• Joints are often held together by ligaments.
• A ligament is a tough band of connective
tissue that attaches one bone to another.
• In movable joints, the ends of bones are
covered by cartilage.
• This layer of cartilage allows for smooth
movement between the bones.
32.2
Joints: Where bones meet
• In addition, joints such as those of the
shoulder and knee have fluid-filled sacs
called bursae located on the outside of
the joints.
• The bursae act to decrease
friction and keep bones and
tendons from rubbing against
each other.
32.2
Joints: Where bones meet
• Tendons, which are thick bands of connective
tissue, attach muscles to bones.
• Forcible twisting of a joint, called a sprain,
can result in injury to the bursae, ligaments,
or tendons.
• A sprain most often occurs at joints with
large ranges of motion such as the wrist,
ankle, and knee.
32.2
Joints: Where bones meet
• One common joint disease is arthritis, an
inflammation of the joints.
• One kind of arthritis results in bone spurs,
or outgrowths of bone, inside the joints.
• Such arthritis is especially painful, and
often limits a person’s ability to move his
or her joints.
32.2
Compact and spongy bone
• Bones are composed of two different types of
bone tissue: compact bone and spongy bone.
Marrow
cavity
Compact
bone
Spongy
bone
Humerus
Periosteum
Artery
Vein
32.2
Compact and spongy bone
• Surrounding every bone is a layer of hard
bone, or compact bone.
Marrow
cavity
Compact
bone
Spongy
bone
Humerus
Periosteum
Artery
Vein
32.2
Compact and spongy bone
• Running the length of
compact bone are tubular
structures known as osteon
or Haversian (ha VER zhen)
systems.
• Compact bone is made
up of repeating units of
osteon systems.
Cartilage
Spongy
bone
Marrow
cavity
Compact
bone
Blood
vessel
Membrane
32.2
Compact and spongy bone
• Living bone cells, or
osteocytes (AHS tee oh
sitz), receive oxygen
and nutrients from small
blood vessels running
within the osteon
systems.
Capillary
Spongy
bone
Osteon
systems
Artery
Vein
32.2
Compact and spongy bone
Cartilage
Spongy
bone
• Compact bone surrounds
less dense bone known as
spongy bone because, like
a sponge, it contains many
holes and spaces.
Marrow
cavity
Compact
bone
Blood
vessel
Membrane
32.2
Cartilage
Formation of Bone
• The skeleton of a
vertebrate embryo is
made of cartilage.
• By the ninth week of
human development,
bone begins to replace
cartilage.
Bone
Marrow
cavity
Blood
supply
32.2
Cartilage
Formation of Bone
• Blood vessels
penetrate the
membrane covering
the cartilage and
stimulate its cells to
become potential
bone cells called
osteoblasts.
Bone
Marrow
cavity
Blood
supply
32.2
Formation of Bone
• These potential bone
cells secrete a protein
called collagen in
which minerals in the
bloodstream begin to
be deposited.
Marrow
cavity
32.2
Formation of Bone
• The deposition of
calcium salts and other
ions hardens the newly
formed bone cells, now
called osteocytes.
Marrow
cavity
32.2
Bone growth
• Your bones grow in both length and diameter.
• Growth in length occurs at the ends of bones
in cartilage plates.
• Growth in diameter occurs on the outer
surface of the bone.
• After growth stops, bone-forming cells are
involved in repair and maintenance of bone.
32.2
Skeletal System Functions
• The primary function of your skeleton is
to provide a framework for the tissues of
your body.
• The skeleton also protects your internal
organs, including your heart, lungs, and
brain.
32.2
Skeletal System Functions
• Muscles that move the body need firm
points of attachment to pull against so
they can work effectively.
• The skeleton provides these attachment points.
32.2
Skeletal System Functions
• Bones also produce blood cells.
• Red marrow—found in the humerus,
femur, sternum, ribs, vertebrae, and
pelvis—is the production site for red
blood cells, white blood cells, and cell
fragments involved in blood clotting.
32.2
Skeletal System Functions
• Yellow marrow,
found in many
other bones,
consists of stored
fat.
Yellow bone
marrow
32.2
Bones store minerals
• Your bones serve as storehouses for
minerals, including calcium and phosphate.
• Calcium is needed to form strong, healthy
bones and is therefore an important part of
your diet. It is also needed for muscle
contractions & nerve impulses.
32.2
Bone injury and disease
• Bones tend to become more
brittle as their composition
changes with age.
• For example, a disease called osteoporosis
(ahs tee oh puh ROH sus) involves a loss of
bone volume and mineral content, causing the
bones to become more porous and brittle.
32.2
Bone injury and disease
• When bones are broken
a doctor moves them
back into position and
immobilizes them with
a cast or splint until the
bone tissue regrows.
32.2
Question 1
What type of joint is illustrated in this image?
A. ball and socket
B. hinge
C. pivot
D. gliding
32.2
The answer is C. Pivot joints allow
bones to twist around each other.
32.2
Question 2
Where, on the body, would you find bursae?
A. skull
B. hands
C. shoulder
D. pelvis
32.2
The answer is C,
shoulder. Bursae are
fluid-filled sacs located
on the outside of the
joints. They act to
decrease friction.
32.2
Question 3
What disease causes the bones to become
brittle?
A. arthritis
B. osteoporosis
C. a sprain
D. phosphate deficiency
The answer is B. Osteoporosis involves a
loss of bone volume and mineral content.
32.3
Section Objectives:
• Classify the three types of muscles.
• Analyze the structure of a myofibril.
• Interpret the sliding filament theory.
32.3
Three Types of Muscles
• Nearly half of your body mass is muscle.
• A muscle consists of groups of
fibers, or cells, bound together.
Smooth
muscle
fiber
• One type of tissue, smooth muscle,Nucleus
is found in the walls of your
internal organs (digestive organs,
reproductive organs, etc.) and blood
vessels. Smooth muscle cells only
have one nucleus.
32.3
Three Types of Muscles
• The most common function
of smooth muscle is to
squeeze (contract) with
slow, prolonged
contractions., exerting
pressure on the space inside
the tube or organ it
Large and Small Intestine
surrounds in order to move
material through it.
32.3
Three Types of Muscles
• Because contractions of
smooth muscle are not
under conscious control,
smooth muscle is
considered an involuntary
muscle.
Large and Small Intestine
32.3
Three Types of Muscles
• Another type of involuntary
muscle is the cardiac muscle,
which makes up your heart.
It has stripes on it and is thus
said to be striated.
• Cardiac muscle fibers are
interconnected and form a
network that helps the
heart muscle contract
efficiently.
Cardiac
muscle
fiber
Striation
Nucleus
32.3
Three Types of Muscles
• Like smooth muscle, cardiac
muscle has only one nucleus
and is also involuntary.
• Cardiac muscle is found
only in the heart and is
adapted to generate and
conduct electrical impulses
necessary for its powerful
and efficient rhythmic
contractions.
Heart
32.3
Three Types of Muscles
• The third type of muscle
tissue, skeletal muscle, is
the type that is attached to
and moves your bones.
• Like skeletal muscle, it is
striated. It undergoes short,
strong contractions.
Skeletal
muscle
fiber
Nucleus
Striation
32.3
Three Types of Muscles
• A muscle that contracts
under conscious control
is called a voluntary
muscle.
Each cell has many
nuclei and is thus said
to be multinucleated.
Skeletal Arm Muscle
32.3
Skeletal Muscle Contraction
The majority of skeletal muscles work in opposing pairs.
32.3
Skeletal Muscle Contraction
• Muscle tissue is made up of muscle fibers,
which are actually just very long, fused
muscle cells.
• Each fiber is made up of similar units
called myofibrils (mi oh FI brulz).
32.3
Bone
Tendon
Skeletal muscle
Skeletal Muscle
Contraction
• Myofibrils are
themselves
composed of even
smaller protein
filaments that can
be either thick or
thin.
Bundles of
muscle fibers
Myofibril
Filaments Actin
Myosin
Sarcomere
32.3
Bone
Tendon
Skeletal muscle
Skeletal Muscle
Contraction
• The thicker
filaments are made
of the protein
myosin, and the
thinner filaments
are made of the
protein actin.
Bundles of
muscle fibers
Myofibril
Filaments Actin
Myosin
Sarcomere
32.3
Bone
Tendon
Skeletal muscle
Skeletal Muscle
Contraction
• Each myofibril can
be divided into
sections called
sarcomeres (SAR
kuh meerz), the
functional units of
muscle.
Bundles of
muscle fibers
Myofibril
Filaments Actin
Myosin
Sarcomere
32.3
Skeletal Muscle Contraction
Click image to view movie.
32.3
Skeletal Muscle Contraction
• The sliding filament theory currently
offers the best explanation for how
muscle contraction occurs.
• The sliding filament theory states that,
when signaled, the actin filaments within
each sarcomere slide toward one another,
shortening the sarcomeres in a fiber and
causing the muscle to contract.
32.3
Bone
Tendon
Skeletal muscle
Skeletal Muscle
Contraction
Muscle structure
Bundles of
muscle fibers
Myofibril
Filaments Actin
Nerve signal
Myosin
Sarcomere
32.3
Skeletal Muscle Contraction
32.3
32.3
Muscle Strength and Exercise
• Muscle strength does not depend on the
number of fibers in a muscle.
• Rather, muscle strength depends on the
thickness of the fibers and on how many
of them contract at one time.
32.3
Muscle Strength and Exercise
• Regular exercise physically
stresses muscle fibers slightly;
to compensate for this added
workload, the fibers increase in
diameter by adding layers of
protein & myofibrils.
• Muscle cells are continually
supplied with ATP from both
aerobic and anaerobic processes.
32.3
Muscle Strength and Exercise
• Muscles are supplied with ATP by one of 2
methods – aerobic processes are at work
when there is an adequate supply of oxygen
available.
• When an adequate supply of oxygen is
unavailable, such as during vigorous activity,
an anaerobic process - specifically lactic acid
fermentation—becomes the primary source of
ATP production.
32.3
Muscle Strength and Exercise
• During vigorous exercise, lactic acid builds up
in muscle cells.
Blood lactic acid
Blood Lactic Acid Levels During Exercise
Shift toward
anaerobic
process
Work rate
32.3
Muscle Strength and Exercise
• As the excess lactic acid is passed into the
bloodstream, the blood becomes more
acidic, rapid breathing is stimulated, and
cramping can occur.
• As you catch your breath following exercise,
adequate amounts of oxygen are supplied to
your muscles and lactic acid is broken down.
32.3
Skeletal Muscle Strength
• Slow-twitch muscles
• Slow-twitch muscle fibers have more
endurance than fast-twitch muscle
fibers.
• They contain myoglobin, a respiratory
molecule that stores oxygen and serves
as an oxygen reserve.
32.3
Fast-Twitch Muscles
• Fast-twitch muscle fibers fatigue easily
but provide great strength for rapid,
short movements.
 They rely on anaerobic metabolism, which
causes a buildup of lactic acid.
32.3
Question 1
What is the difference between cardiac
muscle and smooth muscle?
Cardiac Muscle
Smooth Muscle
32.3
Cardiac muscle is striated and found only in
the heart. It is designed to generate and
conduct electrical impulses. Smooth muscle
is found in the walls of your internal organs.
It is nonstriated.
Cardiac Muscle
Smooth Muscle
32.3
Question 2
What can you conclude about oxygen consumption
during exercise by looking at this graph?
Oxygen Consumption During Exercise
Work rate
32.3
As an individual increases the intensity of
his/her workout, the need for oxygen also
increases in predictable increments.
Oxygen Consumption During Exercise
Work rate
32.3
Question 3
What is the sliding filament theory?
Answer
The sliding filament theory explains how
muscles contract. It states that when signaled,
the actin filaments within each sarcomere
slide toward one another, shortening the
sarcomeres in a fiber, causing the muscle to
contract.
Skin: The Body’s Protection
• Skin is composed of the epidermis and dermis,
with each layer performing various functions.
• Skin regulates body temperature, protects the
body, and functions as a sense organ.
• Skin responds to injury by producing
new cells and signaling a response to
fight infection.
Bones: The Body’s Support
• The skeleton is made up of the axial
and appendicular skeletons.
• Joints allow movement between two
or more bones where they meet.
• Osteocytes are living bone cells.
Bones: The Body’s Support
• Bones are formed from cartilage as a human
embryo develops.
• The skeleton supports the body; provides a
place for muscle attachment, protects vital
organs, manufactures blood cells, and serves
as a storehouse for calcium and phosphorus.
Muscles for Locomotion
• There are three types of tissue: smooth,
cardiac, and skeletal. Smooth muscle lines
organs, contracting to move materials
through the body. Cardiac muscle contracts
rhythmically to keep the heart beating.
Skeletal muscle is attached to bones and
contracts to produce body movements.
Muscles for Locomotion
• Muscle tissue consists of muscle fibers,
which can be divided into smaller units
called myofibrils.
• Muscles contract as filaments within the
myofibrils slide toward one another.
Question 1
What does muscle strength depend on?
Answer
Muscle strength depends on the thickness
of the muscle fibers and on how many of
them contract at one time.
Question 2
Study the diagram. What part of the skin is
number two referring to?
A. hair follicle
3
B. vein
C. muscle
D. sweat pore
4
1
2
The answer is A, hair follicle.
3
4
1
2
Question 3
What becomes the primary source of ATP
production for your muscles during heavy
exercise?
A. cellular respiration
B. muscle contraction
C. myosin
D. lactic acid fermentation
The answer is D, lactic acid fermentation.
Blood lactic acid
Blood Lactic Acid Levels During Exercise
Shift toward
anaerobic
process
Work rate
Question 4
What type of joint is used when
you kick a soccer ball?
A. ball and socket
B. hinge
C. pivot
D. gliding
The answer is B. Hinge joints are found in
your knees and toes, both of which you use
when you kick a soccer ball.
Hinge
Question 5
What type of burn results in damage to the
dermis and epidermis as well as blistering
and scaring?
A. first-degree
B. second-degree
C. third-degree
D. fourth-degree
The answer is B. Second degree burns can
cause damage to the dermis and epidermis,
but skin function is not lost.
Question 6
What are newly formed bone cells called?
A. osteocytes
B. osteoblasts
C. compact bone
D. spongy bone
The answer is A, osteocytes.
Capillary
Spongy
bone
Osteon
systems
Artery
Vein
Question 7
When does bone begin to replace
cartilage in a human embryo?
A. during the last trimester
B. at the 12th week
C. at birth
D. at the 9th week
The answer is D. Blood vessels penetrate the
membrane covering the cartilage and stimulate
its cells to become potential bone cells.
Photo Credits
• PhotoDisc
• Corbis
• Latent Image
• Tim Courlas
• KS Studios
• Digital Stock
• Doug Martin
• Alton Biggs
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