Key Points P ROTECTION MO VEMENT S UPPORT

Big Ideas 1.B.1: Organisms share many conserved core processes and features that evolved and are widely distributed among organisms today. © 2011 Pearson Education, Inc.

Big Ideas 2.A.1: Organisms use free energy to maintain organization, grow, and reproduce (e.g. Krebs Cycle  ATP  muscle contraction) 2.B.1: Cell membranes are selectively permeable due to their structure 2.B.3: Eukaryotic cells maintain internal membranes that partition the cell into specialized regions (e.g. sarcoplasmic reticulum) © 2011 Pearson Education, Inc.

Big Ideas 3.E.1: Individuals can act on information and communicate it to others. Organisms exchange information with each other in response to internal changes and external cues, which change behavior. (e.g. fight or flight response)fight or flight response 3.E.2 d): Animals have nervous systems that detect external and internal signals, transmit and integrate information and produce responses. Different regions of the vertebrate brain have different functions. (e.g. vision, hearing) © 2011 Pearson Education, Inc.

Big Ideas 4.A.3: Interaction between external stimuli and regulated gene expression result in specialization of cells, tissues, and organs. 4.A.4 a): Organisms exhibit complex properties due to interactions between their constituent parts (e.g. muscle & skeletal/nervous systems/sensory mechanisms) 4.A.4 b): Interactions and coordination between systems provide essential biological activities ( e.g. sensory/motor) 4.B.2 a.2): Within multicellular organisms, specialization of organs contributes to the overall functioning of the organism (e.g. communication & control) © 2011 Pearson Education, Inc.

AP Exam 2008

Key Points Skeletal systems transform muscle contraction into locomotion.

Movement And Locomotion Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings (a) Locomotion requires energy to overcome friction and gravity (b) Skeletons support and protect the animal body and are essential to movement (c) Muscles move skeletal parts by contracting (d) Interactions between myosin and actin generate force during muscle contractions

(a) Locomotion requires energy to overcome friction and gravity. A comparison of the energy costs of various modes of locomotion. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig

Swimming Since water is buoyant, gravity is less of a problem when swimming than for other modes of locomotion. However, since water is dense, friction is more of a problem. Fast swimmers have fusiform bodies. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

For locomotion on land, powerful muscles and skeletal support are more important than a streamlined shape. When hopping the tendons in kangaroos legs store and release energy like a spring that is compressed and released – the tail helps in the maintenance of balance. When walking having one foot on the ground helps in the maintenance of balance. When running momentum helps in the maintenance of balance. Crawling requires a considerable expenditure of energy to overcome friction – but maintaining balance is not a problem. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Gravity poses a major problem when flying. The key to flight is the aerodynamic structure of wings. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig

Movement And Locomotion Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings (a) Locomotion requires energy to overcome friction and gravity (b) Skeletons support and protect the animal body and are essential to movement (c) Muscles move skeletal parts by contracting (d) Interactions between myosin and actin generate force during muscle contractions

(b) Skeletons support and protect the animal body and are essential to movement Hydrostatic skeleton Hydrostatic skeleton: consists of fluid held under pressure in a closed body compartment. Form and movement is controlled by changing the shape of this compartment. The hydrostatic skeleton of earthworms allow them to move by peristalsis. Advantageous in aquatic environments and can support crawling and burrowing. Does not allow for running or walking Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Exoskeletons Exoskeletons: hard encasements deposited on the surface of an animal. Mollusks are enclosed in a calcareous exoskeleton. The jointed exoskeleton of arthropods is composed of a cuticle. Regions of the cuticle can vary in hardness and degree of flexibility. About 30 – 50% of the cuticle consists of chitin. Muscles are attached to the interior surface of the cuticle. This type of exoskeleton must be molted to allow for growth. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings (b) Skeletons support and protect the animal body and are essential to movement

Case Study: Chambered Nautilus

Endoskeletons Endoskeletons: consist of hard supporting elements within soft tissues. Sponges have spicules. Echinoderms have plates composed of magnesium carbonate and calcium carbonate. Chordate endoskeletons are composed of cartilage and bone. The bones of the mammalian skeleton are connected at joints by ligaments. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings (b) Skeletons support and protect the animal body and are essential to movement

Movement And Locomotion Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings (a) Locomotion requires energy to overcome friction and gravity (b) Skeletons support and protect the animal body and are essential to movement (c) Muscles move skeletal parts by contracting (d) Interactions between myosin and actin generate force during muscle contractions

(c) Muscles move skeletal parts by contracting Muscles come in antagonistic pairs. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig

Key Points The physical interaction of protein filaments is required for muscle contraction.

Cellular and Skeletal Underpinning of Locomotion. Cellular and Skeletal Underpinning of Locomotion. On a cellular level all movement is based on contraction (flexion & extension). Either the contraction of microtubules or the contraction of microfilaments. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings See Figure 50.26: Myofibril Structure

Illustrative Examples: 1.Sliding Filament Model (Actin-Myosin Interactions) 2.Regulation of Skeletal Muscle Contraction Illustrative Examples

Structure and Function of Vertebrate Skeletal Muscle. sarcomere is the functional unit of muscle contraction. thin filaments consist of two strands of actin and one tropomyosin coiled about each other. thick filaments consist of myosin molecules. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig

Movement And Locomotion Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings (a) Locomotion requires energy to overcome friction and gravity (b) Skeletons support and protect the animal body and are essential to movement (c) Muscles move skeletal parts by contracting (d) Interactions between myosin and actin generate force during muscle contractions

Illustrative Examples: 1.Sliding Filament Model (Actin-Myosin Interactions) 2.Regulation of Skeletal Muscle Contraction Illustrative Examples

(d) Interactions between myosin and actin generate force during muscle contractions The “sliding-filament model” of muscle contraction. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig See Figure 50.28: Sliding Filament Model

(d 1 ) Calcium ions and regulatory proteins control muscle contraction At rest tropomyosin blocks the myosin binding sites on actin. When calcium binds to the troponin complex a conformational change results in the movement of the tropomyosin- troponin complex and exposure of actin’s myosin binding sites. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig (See handout)

But, where do the calcium ions come from? Follow the action potential. When an action potential meets the muscle cell’s sarcoplasmic reticulum (SR), stored Ca 2+ is released. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig

Review of skeletal muscle contraction. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig (see Movement & Locomotion handout) See Figure 50.30: Contraction System

(d 2 ) Diverse body movements require variation in muscle activity An individual muscle cell either contracts completely or not all. Individual muscles, composed of many individual muscle fibers, can contract to varying degrees. One way variation is accomplished by varying the frequency of action potentials reach the muscle from a single motor neuron. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig

Graded muscle contraction can also be controlled by regulating the number of motor units involved in the contraction. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings Fig

Fast and Slow Muscle Fibers. Fast and Slow Muscle Fibers. Fast muscle fibers are adapted for rapid, powerful contractions. Fatigue relatively quickly. Slow muscle fibers are adapted for sustained contraction. Relative to fast fibers, slow fibers have: Less SR  Ca 2+ remains in the cytosol longer. More mitochondria, a better blood supply, and myoglobin. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Other Types of Muscle Other Types of Muscle In addition to skeletal muscle, vertebrates have cardiac and smooth muscle. Cardiac muscle: similar to skeletal muscle. Intercalated discs facilitate the coordinated contraction of cardiac muscle cells. Can generate there own action potentials. Action potentials of long duration. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Fig. 40.4

Smooth muscle: lacks the striations seen in both skeletal and cardiac muscle. Contracts with less tension, but over a greater range of lengths, than skeletal muscle. No T tubules and no SR. Ca 2+ enters the cytosol from via the plasma membrane. Slow contractions, with more control over contraction strength than with skeletal muscle. Found lining the walls of hollow organs. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings

Movement And Locomotion Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings (a) Locomotion requires energy to overcome friction and gravity (b) Skeletons support and protect the animal body and are essential to movement (c) Muscles move skeletal parts by contracting (d) Interactions between myosin and actin generate force during muscle contractions