Transcript 30. How Animals Move

Chapter 30
How Animals Move
PowerPoint Lectures for
Biology: Concepts and Connections, Fifth Edition
– Campbell, Reece, Taylor, and Simon
Lectures by Chris Romero
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Elephants Do the "Groucho Gait"
• Movement is one of the most distinctive
features of animals, from elephants to Groucho
• Movement is dependent on precise interaction
among three organ systems
– Nervous system issues commands to
muscular system
– Muscular system exerts force that makes
the animal move
– Skeletal system provides the firm structure
that muscular force works against
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MOVEMENT AND LOCOMOTION
30.1 Diverse means of animal locomotion have
evolved
• Locomotion: active travel from place to place
– Animal must use energy to overcome
friction and gravity
• Swimming
– Water supports against gravity but offers
frictional resistance
– Different body structures are used to swim
– A streamlined body aids rapid swimming
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• Locomotion on Land: Hopping, Walking,
Running, and Crawling
– Animals that hop, run, or walk must expend
energy to propel themselves and stay
upright
– Burrowing or crawling animals must
overcome friction
• May move by side-to-side undulation or by
peristalsis
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LE 30-1d
Longitudinal
muscle
relaxed
(extended)
Circular
muscle
contracted
Circular
muscle
relaxed
Longitudinal
muscle
contracted
Head
Bristles
• Flying
– The wings of birds, bats, and flying insects
are airfoils
• Shape alters air currents
• Pressure differences create lift
• At the cellular level, all animal movement has
similarities
– Based on contractions of microtubules or
microfilaments
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LE 30-1e
Video: Clownfish and Anemone
Video: Flapping Geese
Video: Soaring Hawk
Video: Swans Taking Flight
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SKELETAL SUPPORT
30.2 Skeletons function in support, movement,
and protection
• A skeleton has many functions
– Body support
– Movement as muscles act against it
– Protection of internal organs
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• Hydrostatic skeleton
– Consists of fluid held under pressure in a
closed body compartment
– Works well for aquatic animals and those
that burrow by peristalsis
• Most are soft and flexible (example:
hydra)
Video: Hydra Eating Daphnia
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• Exoskeleton
– Rigid, external covering with muscles
attached at inner surface
– Arthropod chitin exoskeleton
• Thin and flexible at joints
• Secreted by living cells
• Must be molted periodically, leaving the
animal unprotected
– Mollusc calcium carbonate exoskeleton
• Enlarges by adding to outer edge
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LE 30-2c
Shell (exoskeleton)
Mantle
• Endoskeleton
– Hard or leathery supporting elements
situated among the soft tissues
– Vertebrate skeleton consists of cartilage or
combination of cartilage and bone
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30.3 The human skeleton is a unique variation on
an ancient theme
• Skeletons of vertebrates have a number of
similarities
– Axial skeleton
• Skull, vertebrae, and ribs
– Appendicular skeleton in most
• Shoulder girdle, upper limbs, pelvic
girdle, lower limbs
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• The human skeleton reflects bipedal evolution
– Skull is large, flat-faced, balanced on top of
backbone
– Backbone is S-shaped
– Pelvic girdle is shorter, rounder, and
oriented vertically
– Bones of hands and feet are adapted for
different functions
• Hands: grasping and manipulating
• Feet: support the entire body bipedally
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 30-3a
Skull
Examples
of joints
Shoulder
girdle
Clavicle
Scapula
Sternum
Ribs
Humerus
Vertebra
Radius
Ulna
Pelvic
girdle
Carpals
Phalanges
Metacarpals
Femur
Patella
Tibia
Fibula
Tarsals
Metatarsals
Phalanges
LE 30-3b
Baboon
(quadrupedal)
Human
(bipedal)
• The versatility of the vertebrate skeleton
comes in part from its movable joints
– Ball-and-socket joints allow movement in all
directions
– Hinge joints permit movement in one plane
– Pivot joints allow bones to rotate
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LE 30-3c
Head of
humerus
Humerus
Scapula
Ulna
Ulna
Radius
Ball-and-socket joint
Hinge joint
Pivot joint
30.4 Bones are complex living organs
• Bones consist of several kinds of moist, living
tissue
– Fibrous connective tissue covers the outer
surface
– Cartilage cushions the joints
– Bone cells live in a matrix of flexible
collagen fibers embedded in hard calcium
and phosphate
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• Long bones have a central cavity
– Stores yellow bone marrow, which is mostly
stored fat
• Spongy bone is at the ends of long bones
– Contains red marrow, which produces blood
cells
• Blood vessels and nerves coursing through
channels service bone cells
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LE 30-4
Cartilage
Spongy
bone
(contains red
bone marrow)
Compact
bone
Central
cavity
Yellow
bone marrow
Fibrous
connective
tissue
Blood
vessels
Cartilage
CONNECTION
30.5 Broken bones can heal themselves
• Two factors determine whether a bone might
break
– Strength of skeleton
– Angle and amount of force applied
• Bone cells can build new bone and heal a
break, given the opportunity
– Realignment; splint or cast; traction
• Severely injured or diseased bone must be
replaced
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CONNECTION
30.6 Weak, brittle bones are a serious health
problem, even in young people
• Osteoporosis is a bone disease characterized
by low bone mass and structural degeneration
of the bone matrix
• Lowered estrogen production makes this a
problem among older women
• Unhealthy lifestyles have made osteoporosis a
serious concern for young people
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MUSCLE CONTRACTION AND MOVEMENT
30.7 The skeleton and muscles interact in
movement
• Muscles are connected to bones by tendons
• Antagonistic pairs of muscles produce
movement
– A muscle can only contract
– To extend, a muscle must be pulled by the
contraction of an opposing muscle
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LE 30-7
Biceps contracted,
triceps relaxed
(extended)
Triceps
contracted,
biceps relaxed
Biceps
Biceps
Triceps
Triceps
Tendon
30.8 Each muscle cell has its own contractile
apparatus
• A muscle consists of bundles of parallel
muscle fibers
• Each muscle fiber is a bundle of smaller
myofibrils
– A single cell with many nuclei
• Each myofibril consists of repeating units
called sarcomeres
• A sarcomere, composed of overlapping thick
myosin and thin actin filaments, is the muscle's
contractile apparatus
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 30-8
Muscle
Bundle of
muscle fibers
Single muscle fiber
(cell)
Nuclei
Video: Sliding Filament Theory
Myofibril
Light
band
Dark
band
Light
band
Z line
Sarcomere
Thick
filaments
(myosin)
Light
band
Dark
band
Light
band
Thin
filaments
(actin)
Z line
Z line
Sarcomere
30.9 A muscle contracts when thin filaments slide
across thick filaments
• The sliding-filament model of muscle
contraction
– A sarcomere contracts when its thin
filaments slide across its thick filament
– Contraction is caused by energy-consuming
interactions of myosin and actin molecules
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– The sequence of detach-extend-attach-pull
occurs repeatedly
• ATP binds to a myosin head, which is
released from an actin filament
• Hydrolysis of ATP extends the myosin
head
• The myosin head attaches to an actin
binding site
• The power stroke slides the actin (thin)
filament toward the center of the
sarcomere
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 30-9b-4
Thick filament (myosin)
Thin filament
(actin)
Z line
ATP
Myosin
head
ATP binds to a myosin head, which is released
from an actin filament.
ADP
P
Hydrolysis of ATP extends the myosin head.
SlidingFilament.MOV
ADP
P
The myosin head attaches to an actin binding site.
New position of Z line
ADP + P
The power stroke slides the actin (thin) filament toward the
center of the sarcomere.
30.10 Motor neurons stimulate muscle
contraction
• A motor unit consists of a motor neuron and
the muscle fibers it controls
• A motor neuron can stimulate more than one
muscle fiber because of its many branches
– Neuron's axons form neuromuscular
junctions with muscle fibers
– Action potential from neuron triggers
release of acetylcholine
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– Acetylcholine diffuses across
neuromuscular junctions to muscle fibers
– Change in fiber membrane permeability
triggers action potentials that pass into the
center of the muscle cell
– Calcium released from the endoplasmic
reticulum initiates filament sliding and
muscle contraction
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
LE 30-10a
Spinal cord
Motor Motor
unit 1 unit 2
Nerve
Motor neuron
cell body
Motor neuron
axon
Neuromuscular
junctions
Nuclei
Muscle fibers
(cells)
Muscle
Tendon
Bone
LE 30-10b
Motor neuron
axon
Action potential
Mitochondrion
Tubule
Endoplasmic
reticulum (ER)
Ca2+
released
from ER
Myofibril
Plasma membrane
Sarcomere
CONNECTION
30.11 Athletic training increases strength and
endurance
• Aerobic and anaerobic exercise must be
balanced
• Aerobic exercise increases efficiency and
fatigue resistance of muscles
– Increases blood flow and mitochondria size
– Strengthens heart and circulatory system
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• Anaerobic exercise builds larger muscles that
generate greater power
– Increases size of muscle fibers
– More glycogen stored as fuel reserve
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
30.12 The structure-function theme underlies all
the parts and activities of an animal
• Animal movement is a visible reminder that
function emerges from structure
– Integrates the sensory, nervous, and motor
systems
• Athletic ability results from adaptations that
have been refined through natural selection
and contribute to our survival as a species
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings