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Support and Locomotion
Support and Locomotion
Organisms that are capable locomotion are Motile,
Those that don’t move much are Sessile
What are some advantages of
Locomotion?
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Getting Food
Find places to live
Move away from harmful conditions
Escape enemies
Find shelter
Mating and Reproduction
Need for support: Skeletons
• Some are made of hard material,
others are soft.
:Calcium compounds, chitin.
• Muscles are attached to it.
• Types:
– Hydrostatic
– Endoskeleton
– Exoskeleton
Types of Skeletons
1. Hydrostatic Skeleton:
-Fluid held under pressure in
closed body compartment.
• i.e.: hydra, earthworm
How does this provide support?
1. Protects body parts
2. Gives body its shape
3. Provides support for muscle
action
What are its limitations?
1.
2.
Motility
posture
Hydrostatic Skeletons
Protist Locomotion
• Motile Protists use:
– pseudopods
– Cilia
– flagella
Locomotion
1. Pseudopod
• temporary projections
of the cell surfaces.
• Cytoplasm flows into
and out of the
pseudopod.
• Only occurs on solid
surfaces.
Ex: Ameoba Locomotion
• Cytoplasm is in two states
– Endoplasm – center of cell, more fluid
– Ectoplasm - fluid moves into pseudopod and spreads out
becoming less fluid
– Ectoplasm moves to back of cell and becomes endoplasm again
• 2. Cilia
– Hair-like structures (thousands) that move in rhythmic
beating movements that move an organism through
water. (Paramecium)
• 3. Flagella
– Like cilia but longer
– Usually only 1 or 2 per cell
– Whip-like movements propel cell through water.
(Euglena)
Hydra Locomotion
1.
2.
3.
4.
5.
Contractile fibers – move in several
ways
Mucus secreting cells & amoeboid
cells – glide along its base
Somersaulting
Inch along attaching its tentacles and
pulling itself
Float upside down by making an air
bubble in its base
Earthworm Locomotion
• Two layers of muscles:
– Outer Circular layer
– Inner Longitudinal Muscles
• When circular muscles contract,
the worm gets longer, when the
longitudinal muscles contract the
worm gets shorter
• Fluid inside worm stiffens when
muscles contract, allow it to push
through soil
• Setae: four pairs of bristles on
each segment; act as anchor
How does this happen?
1.
2.
3.
4.
5.
Setae in rear hook into ground
Circular muscles contract and
fluid stiffens
Earthworm lengthens and pushes
through soil
Setae in front of worm anchor into
soil, setae in the rear relax and
un-anchor.
Longitudinal muscles contract,
shortening the body and pulling
the backend forward
Types of Skeletons
2. Exoskeleton:
- skeleton is on the outside of
the body. ( clams, crabs,
lobster, oysters)
• Crabs, insects: exoskeleton
made of chitin
- Protection
- Can not grow.
Exoskeletons
Grasshopper
• Exoskeleton composed of chitin
• Divided into plates, separated
by joints
• Walk, jump, fly.
• Body has three divisions:
– head
– thorax
– abdomen
Grasshopper Exoskeleton
• Thorax:
• 3 pairs jointed legs
• First 2: walking
• Hind pair: jumping
• 2 pairs wings
• Outer pair protects inner
pair (flying)
– Muscles work in pairs
Exoskeletons
• Cicada’s shed exoskeleton
Types of Skeletons
3. Endoskeleton
– Skeleton found inside the
body
– Made of bone and cartilage
(connective tissue)
– Does not protect like an
exoskeleton.
– Skull: brain, Rib cage: organs
– Grows
– Fish, amphibians, reptiles,
birds, mammals
Human Musculoskeletal System
• Endoskeleton
• Bones
– Type of connective tissue
– Hard and inflexible
– Muscles attachment site – serve
as levers
– Support
– Protection
– Storage for minerals (calcium,
phosphorus)
– Produce Red and White blood
cells
Components of Bone
1. Osteoblasts
• Bone makers
• Secrete collagen and minerals
• Osteogenesis
Collagen
– strong protein material
– fibers tied together by
polysaccharides to form cement
Calcium and phosphate Ions
gives bones hardness
and heaviness
4. Osteocytes
• Mature bone forming cells
5. Osteoclasts
• Bone remodelers
(Components continued)
6. Haversian Canals
Cavity containing blood
vessels and nerves.
7. Periosteum
• tough membrane on outside
of bones (except at ends).
• makes new bone for growth
and repair.
• where muscles are attached,
• contains blood vessels and
nerves.
8. Marrow
Red marrow
• makes RBC, platelets and
WBC
• in spongy bone of long
bones, vertebrae, ribs,
breastbone, cranium
Yellow marrow
• made of fat cells
• in hollow center of long bones
Types of Bone
• Compact bone – very dense, strong
• Spongy bone – more porous
• Most bones contain both types of tissue
Human Skeleton
• Contain 206 bones
• Two parts:
– Axial skeleton
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Skull
Vertebrae
Ribs
Breastbone
– Appendicular skeleton
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Arm bones
Leg bones
Pectoral girdle
Pelvic girdle
Joints
• Joints are where bones meet bones
• Types:
– Immovable Joints
– Hinge Joints
Types of Joints
– Ball & Socket Joints
– Pivot Joints
– Gliding Joints
Supportive Structures
• 1. Cartilage
– type of connective
tissue
– Bends easily
– Joint lubrication
– Absorbs force –
cushions against impact
or pressure
– Gives support while
allowing motion
How do you stabilize those joints?
Supportive Structures
2. Ligaments
– Tough connective tissue
– Attach bones to bones
3. Muscles
– Attached to bones
– Pull on bones when contracted
Supportive Structures
4. Tendons
•
connect muscles to bone
Changes in Development
– In embryo, skeleton is cartilage then changes to bone
(ossification)
– Bones of small children are more cartilage than bone
– In adults, found on ends of bones, nose, ears
Muscles
• Muscle Types:
– Skeletal muscles
• Striated
• Used in locomotion and in
voluntary movement
• muscle fibers – group of
cells fused together
• Bundles of muscle fibers
bound by connective tissue
Muscles
• Smooth Muscle
•
•
•
•
Involuntary
Regulated by nerves and hormones
unstriated
Found in:
– Walls of digestive organs
– Walls of arteries and veins
– Diaphragm
Muscles
• Cardiac Muscle
– Involuntary and striated
– In heart
– Regulated by nerves and hormones
Muscle components
• Muscle Fibers
– Are innervated by nerve impulse.
– A motor unit is a nerve and the muscle fiber it
stimulates.
– Consist of myofibrils
• Myosin protein filaments – thick filament (dark)
• Actin filament – thin filament (light)
Components
• Sarcomere: contractile unit
• Many sarcomeres are in a myofibril
• Actin and myosin are in a sarcomere
How does a muscle contract?
Sliding Filament Theory
• Muscle fibers shorten when actin slides over
myosin
• Energy for sliding is by ATP
Take another look
How do muscles work?
• Muscles pull when they contract
• Work in Antagonistic Pairs
– Biceps flex the elbow
– Triceps extend the elbow
• Muscle Tone
– When you are conscious, your
muscles are never completely
relaxed. Muscles are “ready”.
– Responsible for posture