A comparison of the energy costs of various modes of locomotion. Locomotion requires energy to overcome friction and gravity

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.

For locomotion on land powerful muscles and skeletal support are more important than a streamlined shape. –hopping –walking –running –crawling

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

Hydrostatic skeleton: consists of fluid held under pressure in a closed body compartment. –Earthworm –Cniderian –Squid Skeletons support and protect the animal body and are essential to movement

Exoskeletons Endoskeletons Exo & Endoskeletons

Human Skeleton Joint Movement

Muscles come in antagonistic pairs. Muscles move skeletal parts by contracting

The sliding-filament model of muscle contraction. Interactions between myosin and actin generate force during muscle contractions

Calcium ions and regulatory proteins control muscle contraction

Review of skeletal muscle contraction.

An individual muscle cell either contracts completely or not all. Individual muscles, composed of many individual muscle fibers, can contract to varying degrees. Diverse body movements require variation in muscle activity

Contraction Response

–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

Slow-Twitch Versus Fast-Twitch Muscle Fibers

ATP is Generated by: 1.creatine phosphate ADP + creatine phosphate  creatine + ATP 2. lactic acid fermentation From stored glycogen via anaerobic glycolysis; glucose  pyruvic acid (no O 2 )  lactic acid O2O2 3. aerobic respiration Krebs  CO 2 + H 2 O + ATP Energy for muscle contraction: ATP is the only energy source ATP  (ATPase + H 2 O)  ADP + Pi

Fast glycolitic: white muscle fibers, low myoglobin, anaerobic glycolysis, few mitochondria, fast twitch fibers, high glycogen stores, short bursts, fatigues easily Slow oxidative: red muscle, aerobic, high myoglobin, low glycogen stores, lots mitochondria, slow, tonic, long distance Fast oxidative glycolytic: red  pink, aerobic, fast, high myoglobin, intermediate amt. of mitochondria, intermediate glycogen, intermediate fatigue resistance Ratio- red:white (all 3 types in body) Ex. fish- long distance blue fin tuna- mostly red meat quick bursts- yellow tail- more white meat

Sprinter- anaerobic respiration Long distance Runner- aerobic respiration

Other Types of Muscle. –Smooth muscle: No striations Found lining the walls of hollow organs. Autonomic Nervous System Slow contractions –Cardiac muscle:. Intercalated discs facilitate the coordinated contraction of cardiac muscle cells. Striations Autonomic Nervous System