Support & movement in animals (I)

1. Support & movement in animals (I)

2. Movement is dependent on precise interaction among three organ systems ???

3. Nervous system issues commands to muscular system • Muscularsystem exerts force that makes the animal move • Skeletalsystem provides the firm structure that muscular force works against

4. MOVEMENT AND LOCOMOTION Diverse means of animal locomotion have evolved • Locomotion: active travel from place to place • Animal must use energy to overcome friction and gravity

5. Swimming • Water supports against gravity but offers frictional resistance • Different body structures are used to swim • A streamlined body aids rapid swimming

6. The Fins Fins give a fish control over its movements by directing thrust, supplying lift and even acting as brakes. Caudal fin-- provides thrust, and control the fishes direction

7. Myotomes on both sides of the vertebral column Gram for gram fish have more muscle than any other vertebrate, a male salmon or tuna can be nearly 70% muscle.

8. How a fish propels itself through water Drag is minimized by the streamlined shape of the fish and a special slime fishes excrete from their skin that minimizes frictional drag and maintains smooth flow of water past the fish.

9. Locomotion on Land: Hopping, Walking, Running, and Crawling Animals that hop, run, or walk must expend energy to propel themselves and stay upright

11. Airfoil The wings of birds, bats, and flying insects are airfoils -shape alters air currents, Pressure differences create lift Flying

12. LE 30-9b-4

13. SKELETAL SUPPORT Skeletons function in support, movement, and protection • A skeleton has many functions • Body support • Movement as muscles act against it • Protection of internal organs

14. 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)

16. LE 30-1d Longitudinal muscle relaxed (extended) Circular muscle relaxed Circular muscle contracted Longitudinal muscle contracted Head Bristles

17. Exoskeleton • Rigid, external covering with muscles attached at inner surface • Mollusc calcium carbonate exoskeleton • Arthropod chitin exoskeleton • Thin and flexible at joints • Secreted by living cells • Must be molted periodically, leaving the animal unprotected

19. LE 30-2c Shell (exoskeleton) Mantle

21. Endoskeleton • Vertebrate skeleton consists of cartilage or combination of cartilage and bone

22. 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

23. 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

24. LE 30-3a Skull Examples of joints Clavicle Shoulder girdle Scapula Sternum Ribs Humerus Vertebra Radius Ulna Pelvic girdle Carpals Phalanges Metacarpals Femur Patella Tibia Fibula Tarsals Metatarsals Phalanges

25. LE 30-3b Baboon (quadrupedal) Human (bipedal)

26. LE 30-9b-4 Varioustype ofjoints Joints are where bones meet one another

27. Head of humerus Humerus Scapula Ulna Ulna Radius Ball-and-socket joint Hinge joint Pivot joint Movable joints • 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

28. Suture joints –immovable joints that sacrifice movement for support and strength

29. 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

30. Structure of a long bone Cartilage Spongy bone (contains red bone marrow) Compact bone Central cavity Yellow bone marrow Fibrous connective tissue Blood vessels Cartilage LE 30-4 • 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

31. LE 30-9b-4 Compact bone and spongy bone

32. Osteoporosis

33. LE 30-9b-4 Bones are complex living organs

34. LE 30-9b-4 Histology of Compact bone

35. CONNECTION 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

38. 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

39. THE MUSCULAR SYSTEM • Muscles are responsible for all types of body movement • Irritability and contractibility • Three basic muscle types are found in the body • Skeletal muscle • Cardiac muscle • Smooth muscle

40. Characteristics of Muscles • Muscle cells are elongated (muscle cell = muscle fiber) • Contraction of muscles is due to the movement of microfilaments • All muscles share some terminology • Prefix myo refers to muscle • Prefix mys refers to muscle • Prefix sarco refers to flesh

41. THREE TYPES OF MUSCLE

42. Smooth Muscle Characteristics • Has no striations • Spindle-shaped cells • Single nucleus • Involuntary – no conscious control • mainly in the walls of hollow organs Figure 6.2a

43. Cardiac Muscle Characteristics • Has striations • Usually has a single nucleus • Joined to another muscle cell at an intercalated disc • Involuntary • Found only in the heart Figure 6.2b

44. Skeletal Muscle Characteristics • Most are attached by tendons to bones • Cells are multinucleate • Striated – have visible banding • Voluntary – subject to conscious control • Cells are surrounded and bundled by connective tissue

45. Functions of Sleletal Muscles • Produce movement • Maintain posture • Stabilize joints • Generate heat

46. Connective Tissue Wrappings of Skeletal Muscle • Connective tissues wrap around muscles • Muscles are attached to bones through tendon Figure 6.1

47. Skeletal Muscles work in antagonistic pairs Biceps contracted, triceps relaxed (extended) Triceps contracted, biceps relaxed Biceps Biceps Triceps Triceps Tendon A muscle can only contract To extend, a muscle must be pulled by the contraction of an opposing muscle

48. Each muscle cell has its own contractile apparatus A muscle consists of bundles of parallel muscle fibers • Each muscle fiber is a single cell with many nuclei • Each muscle fiber has bundle of smaller myofibrils

49. Microscopic Anatomy of Skeletal Muscle • Sarcolemma – specialized plasma membrane • Sarcoplasmic reticulum – specialized smooth endoplasmic reticulum Figure 6.3a

50. Microscopic Anatomy of Skeletal Muscle • Myofibril • Bundles of myofilaments • Myofibrils are aligned to give distinct bands • I band = light band • A band = dark band Figure 6.3b