1. Sensory & Motor Mechanisms
Ch 49b

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

3. 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.

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

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

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

7. Endoskeletons
Exoskeletons
                          
Exo & Endoskeletons

8. Human Skeleton
Joint Movement

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

10. Structure and Function of Vertebrate Skeletal Muscle.
The 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.

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

12. 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- tropinin complex and exposure of actin’s myosin binding sites.

13. But, wherefore the calcium ions?
Follow the action potential.
When an action potential meets the muscle cell’s sarcoplasmic reticulum (SR) stored Ca2+ is released.

14. Review of skeletal muscle contraction.

15. 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.

16. Contraction Response

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

18. Slow-Twitch Versus Fast-Twitch Muscle Fibers

19. Energy for muscle contraction:
ATP is the only energy source ATP(ATPase + H2O) ADP + Pi
ATP is Generated by:
creatine phosphate
ADP + creatine phosphatecreatine + ATP
2. lactic acid fermentation
From stored glycogen via anaerobic glycolysis;
glucosepyruvic acid (no O2) lactic acid
O2
3. aerobic respiration
KrebsCO2 + H2O + ATP

20. 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: 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

21. Long distance
Runner- aerobic respiration
Sprinter- anaerobic respiration

22. Other Types of Muscle. Smooth muscle: Cardiac 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