Download Unit 10 Chapter 34 Protection, Support, and Locomotion

Unit 10
Chapter 34
Protection, Support,
and Locomotion
Functions of Skin?
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Sensory. Is it important that all skin is
equally sensitive?
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Partner up. One will be the subject, one is the
experimenter.
The subject’s eyes should be closed during the testing. The
experimenter touches the palm of the subject’s hand with a
marker. The subject should then try to touch the exact point
with his/her own marker (different color) with eyes still
closed. Next, forearm, then fingertip.
Measure the error of localization in millimeters. Record on
board.
Which areas have the most sensory receptors? Why?
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Skin: the Body’s Protection
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Integumentary System
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Contains skin and its related parts—
hair, nails & glands
Four tissue types:
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Epithelial – covers the surface of the
body
Connective – tough and flexible protein
fibers, acts like an organic glue
Muscle – Interacts with hairs to
respond to stimuli
Nervous – Allows us to detect external
stimuli (pain, pressure etc)
Skin: the Body’s Protection
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Layers within layers
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Two principle layers, each with unique
structure and function
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Epidermis – has its own layers!
Dermis
Epidermis: Outer layer of
skin
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Exterior portion:
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25-30 layers of dead flattened cells
 Contains keratin: protects and gives
elasticity
Interior portion:
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Living cells that replace the
dead cells
Some contain Melanin,
a pigment that colors the
skin & protects cell from
damage by radiation
Takes about 28 days
Epidermal ridges for grip.
Dermis: Inner Layer of Skin
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Thicker than the Epidermis
Contains blood vessels,
nerves, nerve endings,
hair follicles, sweat
gland and oil glands
Oil glands
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Prevent hair from drying out.
Keeps skin soft. Inhibits bacterial growth
Dermis: Inner Layer of Skin
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Hair follicles
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Narrow cavities out of
which hair growth
Have blood vessels,
muscle and oil glands
associated with them
Sweat Glands
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Average human loses
900 mL of sweat/day!
Skin: the Body’s Protection
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Hypodermis
(subcutaneous layer)
Below the dermis
Contains primarily of fat
for cushioning &
insulation, retaining
heat and storing food.
Skin: Functions
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Regulates body temperature (part of
homeostasis)
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Functions as a sense organ
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Nerve cells receive stimuli from outside and relay
information on the inside.
Produces vitamins – Vitamin D when exposed to
light
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Sweat is released in response to elevated body
temperature
As sweat evaporates, the body cools.
Helps the blood absorb Calcium
Protects underlying tissues
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From physical & chemical damage and microbe invasion
Skin Injury and Healing
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Repair Stages (in response to injury)
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Blood flows to the wound until a clot forms
Scab develops (barrier between bacteria and underlying
tissues)
New skin cells repair the wound from beneath
Bones: the Body’s Support
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Adult skeleton contains
approximately 206
bones
Skeletal System Structure
 Two
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Axial skeleton
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Divisions:
Includes the skull,
vertebrae, ribs & sternum
Appendicular skeleton
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Includes bones of the
arms & legs, and shoulder
& hip bones
Joints: where bones meet
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Joints
 Where two or more
bones meet
 Usually facilitate the
movement of bones
in relation to one
another
 Ends of moveable
bones covered with
cartilage for smooth
movement.
Joints: where bones meet
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Joint Types
 Ball and Socket- hip,
shoulder.
 Pivot – twisting, arm,
head
 Hinge – elbow, knee,
fingers, toes
 Gliding – wrists and
ankles
Bones: the Body’s Support
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Ligaments
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Connective tissue
that attaches one
bone to another
Tendons
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Connective tissue
that attach muscles
to bones
Two types of bone tissue
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Compact bone – layer of
hard bone that surrounds
every bone.
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Composed of osteon/Haversian
systems
 Circular areas containing blood
vessels, nerves and mature
cells called
osteocytes.
Two types of bone tissue
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Spongy bone
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Less dense bone filled with
holes and spaces.
Formation of Bone
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In embryo, the vertebrate
skeleton is made of cartilage
By week 9, bone begins to
replace the cartilage
Formation of Bone
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Blood vessels penetrate the cartilage and the
cells become osteoblasts (potential bone cells)
Osteoblasts secrete collagen (a protein) and
causing minerals to be deposited.
Calcium salts and ions harden, trapping the
osteoblasts and they
become osteocytes.
Bone Growth
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Growth in Length:
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Growth in Diameter (thickness)
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Occurs at the ends of bones in cartilage plates
Occurs at the outer surface of the bone
Accelerated by sex hormones during puberty
Skeletal System Functions
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Provides framework for the tissues in our
body
Protects internal organs
Produces blood cells
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Red marrow- produces RBCs, WBCs and
clotting agents (platelets)
Yellow marrow – stores fat
Stores minerals, including calcium and
phosphates.
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Needed for strong, healthy bones, important
part of diet.
Bone Injury and Disease
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Osteoporosis
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Loss of bone volume and mineral content. Bones
become more porous and brittle with age.
Broken bones
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Shown by X-ray images.
Bones are moved back into position and
immobilized for regrowth.
Muscles for Locomotion
Three types of Muscles
Muscles for Locomotion
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Smooth muscle
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Involuntary movement
Found in hollow body
organs, i.e. digestive
tract, blood vessels
Spindle-shaped cells,
non-striated, one
nucleus per cell
Muscles for Locomotion
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Cardiac muscle
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Involuntary movement
Found only in the heart
Interconnected to form a
network for efficiency
Generate and conduct
electrical impulses
Branching, striated
(striped) cells, with one
nucleus per cell
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Muscles for Locomotion
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Skeletal muscle
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Voluntary movement
Attach to and move bones,
i.e. biceps, triceps,
hamstrings, etc
Long, striated (striped)
cells, with many nuclei
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Skeletal Muscle
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The majority of skeletal muscles work in
opposing pairs. (i.e. flexor and extensor)
Muscles for Locomotion
Common
Skeletal
muscles
Skeletal Muscle Contraction
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.
Muscle tissue is made up of muscle fibers
(long fused cells):
Muscle fibers (cells) are made up of smaller
units called myofibrils
Skeletal Muscle Contraction
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Myofibrils are composed of thick and thin
filaments.
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Thick filament – myosin
Thin filament – actin
Each myofibril can be
divided into sections
called sarcomeres
– functional unit of
muscle.
Skeletal Muscle Contraction
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Muscle contraction:
Sarcomeres contract (shorten) as the filaments,
myosin & actin, slide toward one another.
Sliding filament theory – best explanation,
current model.
link
Exercise
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The number of muscle cells are fixed at the
time of birth.
Working out makes you stronger, but you
don’t get more muscle
Muscle fibers increase in diameter in
response to regular exercise.
Muscle contraction requires ATP. How do we
get ATP?
Produced during cellular
respiration in mitochondria!
Exercise
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During exercise, muscles use oxygen (aerobic
respiration)
This eventually shifts to anaerobic respiration and lactic
acid is produced (fermentation).
Lactic acid builds up. As you catch your breath, more
oxygen is delivered
and lactic acid is
broken down.
Regular exercise
results in improved
performance of
muscles.