Download Chapter 30 How Animals Move

Chapter 30 How Animals Move
Movement and
Locomotion
Locomotion requires the
collaboration of muscles
and skeleton.
The Vertebrate Skeleton
Vertebrates have similar skeletons,
but modifications of the ancestral
body plan resulted in structural
adaptations for different functions.
Muscle Contraction
and Movement
Muscles work with the skeleton
to move the body.
Each muscle cell has its own
contractile apparatus.
Locomotion requires energy to overcome
friction and gravity
 Locomotion 運動
- is active travel from place to place.
- requires energy to overcome friction and gravity.
 Animal movement results from a collaboration between muscles and
a skeletal system to overcome friction and gravity.
(1) Swimming
 An animal swimming is
- supported by water.
- slowed by friction.
A fish swimming
(2) Walking, Hopping, Running
 An animal walking, hopping, or running
- involves less overall friction between air and the animal.
- must resist gravity.
- requires good balance.
(3) Burrowing, Crawling
 An animal burrowing or crawling
- must overcome great friction between the animal and the ground.
- is more stable with respect to gravity.波浪(蛇形)動作
- may move by side-to-side undulations (such as snakes).
Circular Longitudinal
Longitudinal Circular
- may move by a form of
muscle
muscle muscle
muscle
contracted
relaxed contracted
relaxed
peristalsis (such as worms).
(extended)
蠕動
Head
1
Bristles
2
3
(4) Flying
 An animal flying uses its wings as airfoils to generate lift.
白努利原理
Bernoulli's Principle
 An animal flying
- its wings must develop enough
“lift” to completely overcome
the pull gravity.
 Flying has evolved in very few
groups of animals.
Flying animals include
- most insects.
- reptiles, including birds.
- bats (mammals).
Bernoulli
Skeletons function in support, movement, and protection
 Skeletons provide
- body support.
- movement by working with muscles.
- protection of internal organs.
 There are three main types of animal skeletons:
- hydrostatic skeletons. 液壓式(骨骼)骨骼
- exoskeletons. 外骨骼
- endoskeletons. 內骨骼
Hydrostatic skeletons
 Hydrostatic skeletons are
- fluid held under pressure in a closed body compartment.
- found in worms and cnidarians.
 Hydrostatic skeletons
- help protect other body parts by
cushioning them from shocks.
- give the body shape.
- provide support for muscle action.
The hydrostatic skeleton of a hydra in two states
Exoskeletons & Endoskeletons
Exoskeletons
 Exoskeletons are rigid external skeletons that consist of
幾丁質 - chitin (polysaccharide) and protein in arthropods.
碳酸鈣 - calcium carbonate shells in molluscs.
 Exoskeletons must be shed to permit growth.
Shell
(exoskeleton)
Mantle
The exoskeleton of an arthropod: a crab molting
The exoskeleton of a mollusc: a cowrie (a marine snail)
Endoskeletons
 Endoskeletons consist of hard or leathery supporting elements
situated among the soft tissues of an animal.
They may be made of
- cartilage or cartilage and bone (vertebrates).
- spicules (sponges).
- hard plates (echinoderms).
A living sea urchin (left) and its endoskeleton (right)
Bone (tan) and cartilage (blue) in the
endoskeleton of a vertebrate: a frog
The human skeleton
 The human skeleton consists of an
- axial skeleton
中軸骨骼
- that supports the axis or trunk of the body.
- consists of the skull, vertebrae, and ribs.
附肢骨骼
- appendicular skeleton
- that includes the appendages and the bones that anchor t
appendage.
- consists of the arms, legs, shoulders, and pelvic girdles.
axial skeleton (blue)
appendicular skeleton (pink)
Skull
頭蓋骨
鎖骨
胸帶
Clavicle
Pectoral
girdle
Scapula
肩胛骨
Sternum 胸骨
Ribs 肋骨
肱骨
Humerus
尺骨
Vertebra
Radius
Ulna
脊椎骨
support the head
cartilage
Intervertebral
discs
7 cervical
vertebrae
頸椎骨
椎間盤
橈骨
12 thoracic
vertebrae 胸椎骨
Pelvic girdle
腰帶
Carpals
腕骨
joins with the ribs
指骨
Phalanges
Metacarpals
掌骨
Femur
股骨
Patella
膝蓋(髕)骨
Tibia
Hip
bone
髖關節骨
5 lumbar
腰椎骨
vertebrae
Sacrum 薦(椎)骨
Coccyx 尾(椎)骨
脛骨
Fibula
腓骨
跗骨
Tarsals
Metatarsals 掌骨
Phalanges
趾骨
The pattern of master (homeotic) control genes
expressed in the somites 主宰控制基因
Python
Chicken
Thoracic
vertebrae
The forelimbs originate at the boundary
between cervical and thoracic vertebrae
Cervical
vertebrae
Gene expression
during development
Hoxc6
Hoxc8
Hoxc6 and Hoxc8
Expression of two Hox genes in a python (left) and a chicken (right)
Lumbar
vertebrae
The structure of an arm bone
海綿骨
Bone matrix consists of flexible fibers of the
protein collagen with crystals of a mineral
made of calcium and phosphate
緻密骨
Cartilage
Spongy
bone
(contains red
bone marrow)
Compact
bone
Central
cavity
Yellow
bone marrow
Fibrous
connective
tissue
Blood
vessels
Cushions joints and reduces friction of movements
Cartilage
Red bone marrow & Yellow bone marrow
Produces blood cells
store fats
Healthy bones resist stress and heal from injuries
X-rays of a broken leg (left) and the same leg
after the bones were set with a plate and screws (right)
骨痂
Bone repair
Bone remodeling
蝕(破)骨細胞
成骨細胞
成骨細胞
骨細胞
骨質疏鬆症 Osteoporosis
Strong genetic component
 Osteoporosis is a bone disease, characterized by low bone mass
and structural deterioration.
 Less likely if a person
- has high levels of calcium and vitamin D in the diet.
- exercises regularly.
- does not smoke.
Healthy spongy bone tissue (left) and
bone damaged by osteoporosis (right)
Vitamin D in calcium homeostasis
Osteoporosis prevention
Joints permit different types of movement
關節
 Joints
allow limited movement of bones.
韌帶
 Ligaments hold together the bones of movable joints.
 Different
joints permit various movements.
球窩關節,球臼關節,杵臼關節
- Ball-and-socket joints enable rotation in several plans of the arms
and
legs. (humeruspectoral girdle；femurpelvic girdle)
屈戍(鉸鏈)關節
- Hinge joints in the elbows and knees permit movement in a single
plane.
車軸關節
- Pivot joints enable the rotation of the forearm at the elbow, and
movement of the head from side to side
(between the first and second cervical vertebrae).
Head
of humerus
Humerus
Scapula
Ulna
Ulna
Radius
Ball-and-socket joint
Hinge joint
Three kinds of joints
Pivot joint
The skeleton and muscles interact in movement
 Muscles and bones interact to produce movement.
 Muscles are connected to bones by tendons and can only contract,
requiring an antagonistic muscle to 肌腱
- reverse the action.
- relengthen muscles.
Antagonist pairs of muscles
Triceps
contracted,
biceps
relaxed
Biceps contracted,
triceps relaxed
(extended)
二頭肌
Biceps
股四頭肌
Biceps
膕旁肌
Triceps
三頭肌
Tendons
Triceps
Antagonistic action of muscles to pull bones
Contraction of the quadriceps tends to pull the tibia
up or down in the human arm
forward while contraction of the hamstrings tends
to pull it backwards
Each muscle cell has its own contractile apparatus
肌纖維
肌原纖維
 Muscle fibers are cells that consist of bundles of myofibrils.
Skeletal muscle cells
- are cylindrical.
- have many nuclei.
- are oriented parallel to each other.
 Myofibrils
contain overlapping
粗肌絲
- thick細肌絲
filaments composed primarily of the protein myosin.肌凝蛋白
- thin filaments composed primarily of the protein actin. 肌動蛋白
肌小節
 Sarcomeres are
- repeating groups of overlapping thick and thin filaments.
- the contractile unit and the fundamental unit of muscle action.
The contractile apparatus
of skeletal muscle
Muscle
Several muscle fibers
Single muscle fiber
(cell)
Nuclei
Plasma membrane
Myofibril
Light
band
Dark
band
Light
band
Z line
Sarcomere
Thick
filaments
(myosin)
Thin
filaments
(actin)
Z line
Sarcomere
Z line
肌漿網
A muscle contracts when thin filaments
slide along thick filaments
肌絲滑動模型
 According to the sliding-filament model of muscle contraction,
a sarcomere contracts (shortens) when its thin filaments slide across
its thick filaments.
- Contraction shortens the sarcomere without changing the lengths of
the thick and thin filaments.
- When the muscle is fully contracted, the thin filaments overlap in t
middle of the sarcomere.
Sarcomere
Dark band
Z
Z
Relaxed muscle
Contracting
muscle
Fully contracted
muscle
35% shorten
Contracted sarcomere
The sliding-filament model of muscle contraction
The mechanism of filament sliding
Thick filament
Thin
filaments
Z line
Actin
1
Thin
filament
ATP
Myosin head (lowenergy configuration)
Detach
ADP
P
Myosin head (highenergy configuration)
Extend
Thick
filament
2
3
ADP
Attach
Cross-bridge
P
ADP  P
Thin filament moves
toward center of sarcomere.
New
position
of Z line
4
Myosin head (pivoting to
low-energy configuration)
Pull
Power stroke 強移
5
ATP
Myosin head (lowenergy configuration)
Detach
The mechanism of filament sliding
Motor neurons stimulate muscle contraction
 A motor neuron
- carries an action potential to a muscle cell.
- releases the neurotransmitter acetylcholine from its synaptic terminal.
- initiates a muscle contraction.
 An action potential in a muscle cell
- passes along T tubules (transverse tubules). 橫管
- into the center of the muscle fiber.
 Calcium ions
- are released from the endoplasmic reticulum
(SR, sarcoplasmic reticulum).肌漿網
- initiate muscle contraction by moving the regulatory protein.
- tropomyosin away from the myosin-binding sites on actin.
How a motor neuron stimulates muscle contraction
Motor neuron
axon
Mitochondrion
Action potential
Synaptic
terminal
T tubule
Endoplasmic
reticulum (ER)
Myofibril
Plasma membrane
Sarcomere
Ca2
released
from ER
How a motor neurons stimulates muscle contraction
Thin filament, showing the interactions among actin,
regulatory proteins, and Ca2+
Myosin-binding sites blocked
Tropomyosin
Actin
Ca2-binding sites
Troponin complex
Ca2 floods the
cytoplasmic
fluid
Myosin-binding sites exposed
Myosin-binding site
Motor neurons stimulate muscle contraction
運動單位,動作單元
 A motor unit consists of
- a motor neuron.
- the set of muscle fibers it controls.
 More forceful muscle contractions
result when additional motor units
are activated.
Motor units
Motor
unit 1
Spinal cord
Motor
unit 2
Nerve
Motor neuron
cell body
Motor neuron
axon
Synaptic
terminals
Nuclei
Muscle fibers
(cells)
Muscle
Tendon
Bone
The neuromuscular junction 神經肌肉接合處
運動終板
Neuromuscular disorders 神經肌肉病變
肌萎縮性脊髓側索硬化症; 漸凍人症; 路‧蓋里格氏病
(ALS, Amyotrophic lateral sclerosis; Lou Gehrig's disease)
Henry Louis Gehrig
Stephen Hawking
Neuromuscular disorders
小腦萎縮症 (Spinocerebellar Atrophy)
Diagram showing MRI scans of two brains.
The brain on the left shows atrophy
(shrinkage) of the cerebellum. The brain
on the right shows a normal cerebellum.
Aerobic and anaerobic respiration
(1) Aerobic respiration
(2) Anaerobic respiration
Aerobic respiration supplies most of the energy
for exercise
有氧呼吸
 Aerobic respiration
- requires a constant supply of glucose and oxygen.
- provides most of the ATP used to power muscle movement
during exercise.
無氧呼吸
 The anaerobic process of lactic acid (lactate) fermentation
- can provide ATP faster than aerobic respiration.
- is less efficient.
Running, a good form of aerobic exercise
Sources of ATP for athletic activities
Phosphocreatine (PCr) is an ATP source for muscle cells
肌酸
磷酸肌酸
Oxygen debt
Exercise
Recovery
Characteristics of muscle fiber affect athletic performance
 Depending on the pathway they use to generate ATP, muscle fibers
can be classified as
- slow.
- intermediate.
- fast.
dark = slow muscle fibers, light = fast muscle fibers
 Most muscles have a combination of fiber types, which can be
affected by exercise.
 Muscles can adapt to exercise by increasing the
- levels of myoglobin. 肌紅素
- number of mitochondria.
- number of capillaries going to muscles.
Characteristics of muscle fibers
Percentage of total muscle
Percentage of different type of muscle fibers
in quadriceps muscles of different individuals
100
Slow
Intermediate
Fast
80
60
40
20
0
Worldclass
sprinter
Average Average
couch
active
potato
person
(most of us)
MiddleWorld- Extreme
distance
class endurance
runner marathon athlete
runner