1. The Skeletal System: Anatomy
Skeleton gives us our recognizable human form, protects vital internal organs
Bones
Tendons: connect muscles to bones
Ligaments: connect bone to bone
Cartilage: cushions between bones
Lubricated by synovial fluid

2. Overview of Bones Long bones Short bones Flat bones Femur Tibia Fibula
Ulna
Radius
Humerus
Short bones
Bones of wrist
Bones of ankle
Flat bones
Some skull bones
Ribs
Sternum

3. Overview of Bones
Components of a long bone (humerus)

4. Types of Bone Compact bone (solid) Cancellous bone (spongy)
Mostly solid, with few spaces
Contains a central space called marrow cavity
Cancellous bone (spongy)
Consists of lacy network of trabeculae

5. Joints
Formed wherever two long bones come in contact

6. Joints Consist of: Classified as: Ends of bones
Surrounding connecting and supporting tissue
Classified as:
Amphiarthrotic)permits slight mobility(
Diarthrotic)freely movable (
Synarthrotic) permits little or no mobility(

7. Joints
Grouped according to the type of tissue binding them at their junctions:
Fibrous (flat bones)
Cartilaginous (intervertebral disks)
Synovial joints (allow free movement)

8. Joints Synovial joints Ball-and-socket joints Condyloid joints
Gliding (plane) joints
Hinge joints
Pivot joints
Saddle joints

9. Joints Joint capsule Synovial membrane
Fibrous sac that holds the bone ends of a joint together
Synovial membrane
Inner lining of joint capsule that makes synovial fluid

10. Growth and Development of Bones
Begin to form in utero
Osteoblasts develop to osteocytes.
Bones develop from hyaline cartilage.
Growth continues through adolescence.
Osteogenesis: formation of bone

11. Growth and Development of Bones
Ossification
Process of replacing other tissues with bone
Intramembranous ossification: process for the formation of flat bones
© Ralph Hutchings/ Visuals Unlimited

12. Growth and Development of Bones
Flat bones develop from connective tissue membrane to form spongy bone and then compact bone.
When bones are growing, the diaphyses meet the epiphyses at the epiphyseal plate.

13. Growth and Development of Bones
Osteoblast and osteoclast activity is balanced so the bones grow uniformly.

14. The Axial Skeleton Foundation on which arms and legs are hung
Components:
Skull
Face
Thoracic cage
Vertebral column
206 bones of the skeleton

15. The Axial Skeleton Has 28 bones in 3 anatomic groups
Auditory ossicles
Cranium
Face
Connected at special joints called sutures

16. The Axial Skeleton

17. The Axial Skeleton
Facial bones:
Maxillae
Mandible
Zygomas

18. The Axial Skeleton The orbit encloses and protects the eye.
Contains eyeball, muscles, blood vessels, nerves, fat
Blowout fracture:
A blow to the eye may result in fracture of the floor of the orbit.
Blood and fat leak into sinus.

19. The Axial Skeleton Nasal septum separates nostrils.
Paranasal sinus contents drain into nasal cavity.
Sinusitis
Inflammation of the paranasal sinuses

20. The Axial Skeleton Ossicles These bones are known for their shapes:
Contained within the middle ear
Three tiny auditory bones
These bones are known for their shapes:
Hammer (malleus)
Anvil (incus)
Stirrup (stapes)

21. The Axial Skeleton Mandible is made of lower jaw and teeth
Temporomandibular joint
Allows movement of mandible
Hyoid bone
Floats in the superior aspect of the neck, just below the mandible

22. The Neck Supported by cervical spine
First seven vertebrae of spinal column
Esophagus and trachea (windpipe) lie in midline of neck.
On either side of trachea:
Carotid arteries
Jugular veins
Nerves

23. The Neck

24. The Spinal Column

25. The Spinal Column The first cervical vertebra (C1)
Called the atlas
Located directly beneath the skull
Provides support for the head
Atlanto-occipital joint
Where C1 articulates with the occipital condyles at base of the skull
Flexion, extension, and lateral bending are the only motions.

26. The Spinal Column The second cervical vertebra (C2) Known as the axis
Located at the point at which the head rotates left and right.
The dens is an offshoot of C2.
Atlas rotates around the axis at the dens

27. The Spinal Column Vertebrae C3 through C6 form the cervical curve.
C7 is called the vertebra prominens.
Has a large spinous process that may be seen and felt at the base of the neck

28. The Spinal Column
Anterior part of each vertebra consists of a round, solid block of bone called the body.
Posterior part of each vertebra forms a bony arch
Vertebrae are connected by ligaments and separated by an intervertebral disk.

29. The Appendicular Skeleton
Shoulder girdle attaches upper extremity to body
Made up of the scapula (shoulder blade) and clavicle (collarbone)
Acromion process protects shoulder joint

30. The Appendicular Skeleton
The shoulder girdle
Anterior view
Posterior view

31. The Appendicular Skeleton
The upper extremity
The hand and wrist

32. The Pelvic Girdle Also called pelvis
Where lower extremity attaches to body
Contains a ring of bones
Formed by sacrum and coxal
Contains 3 joints

33. The Pelvic Girdle Iliac crest: superior portion of the ilium
Obturator foramen
Opening between the ischium and pubis
Contains several important nerves and muscles
Pelvis supports the body’s weight and protects internal organs

34. The Lower Extremity Hip, thigh, knee, leg, ankle, foot, toes
Acetabulum is the socket that connects the pelvis to the lower extremity
Leg
Femur is the thigh bone
Tibia and fibula make up lower leg

35. The Lower Extremity
The knee

36. The Ankle and Foot
Talus articulates with the tibia and fibula to form the ankle
Ankle made up of seven bones called tarsals
A fibrous capsule surrounds the ankle joint.

37. The Ankle and Foot
Movements include dorsiflexion, plantar flexion, and limited inversion and eversion.
Metatarsals and phalanges are similar to hand bones.
Ball of the foot is junction between metatarsals and phalanges

38. The Lower Extremity
The Ankle and Foot

39. The Skeletal System: Physiology
Bones protect internal organs.
With muscles, bones enable movement.
Bone stores minerals.
Particularly calcium
Plays role in forming blood cells, platelets

40. The Skeletal System: Physiology
Bones consist of
Collagen
Hydroxyapatite (mineral that contains calcium, phosphate)
Mineral components provide strength to bear weight.

41. The Skeletal System: Physiology
In the marrow of certain bones, cells can produce red cells, white cells, and platelets.
Bones are a living tissue requiring a blood supply.
During a person’s lifetime, bones are constantly remodeled to meet the stresses placed on them.

42. The Musculoskeletal System: Anatomy
Provides body’s form, upright posture, movement
Musculoskeletal refers to bones and voluntary muscles of the body.
Protects vital internal organs

43. The Musculoskeletal System: Anatomy
Muscles
Form of tissue that allows body movement
Over 600 muscles in musculoskeletal system
Skeletal muscle found here

44. Skeletal Muscle Attaches bones to the skeleton
Forms major muscle mass of body
Called voluntary muscle
Movement results from contraction or relaxation
Fascia
Separates skeletal muscles from other muscles
Holds skeletal muscles in place

45. Coverings of Connective Tissue
Fascia surrounds every muscle.
May form tendons beyond each muscle’s end
Tendon fibers may intertwine with bone fibers to attach muscle to bones.
Aponeuroses may attach to bones or coverings of other muscles.

46. Coverings of Connective Tissue
Epimysium closely surrounds skeletal muscles
Separated into small compartments by perimysium
The many layers of connective tissue allow a great deal of independent movement.

47. Structure of Skeletal Muscle Fibers
Single cell that contracts in response to stimulation
Thin, elongated cylinders with rounded ends
Sarcolemma lies above the sarcoplasm

48. Structure of Skeletal Muscle Fibers
Sarcoplasm is made up of threadlike myofibrils arranged parallel to each other.
Sarcomeres
Repeating patterns of striation units along each muscle fiber
Muscles considered to be collections of sarcomeres

49. Structure of Skeletal Muscle Fibers
There are two main parts of the striation pattern of skeletal muscles.

50. Structure of Skeletal Muscle Fibers
Sarcoplasmic reticulum
Network of channels that surrounds each myofibril inside the sarcoplasm of a muscle fiber
T-tubules
Other membranous channels extending inward and passing through the fiber

51. Motor Units
Each of the muscle fibers that make up a piece of muscle tissue have a single motor end plate.
When an impulse is transmitted, they all contract at the same time.

52. Contraction of Skeletal Muscles
Skeletal muscles contract when organelles and molecules bind myosin to actin.
Myofibrils move as the actin and myosin filaments slide.

53. Required Chemicals
Actin filaments include the proteins troponin and tropomyosin.
Strands of tropomyosin prevent actin–myosin interaction.
The sarcomere is the functional unit of skeletal muscle.

54. Required Chemicals Sliding filament model
So named because of the way sarcomeres shorten from both ends
Myosin filaments contain the enzyme ATPase.

55. Contraction Stimulus
Nerve impulses transmit the impulses that causes contraction of skeletal muscle.
Also known as action potentials
Depolarization is the process by which cells activate in response to the action potential.

56. Contraction Stimulus
Acetylcholine is the neurotransmitter that stimulates skeletal muscle to contract.
Charged particles stimulate a muscle impulse.
Muscle relaxation is caused by the decomposition of acetylcholine via acetyl cholinesterase.

57. Energy Sources
Muscle fibers have just enough ATP for short-term contraction.
ATP is regenerated from ADP and phosphate.
Creatine phosphate accomplishes this with high-energy phosphate bonds.
Muscles use cellular respiration of glucose as energy to synthesize ATP.

58. Oxygen Use and Debt
Oxygen is required for glucose breakdown in mitochondria.
Red blood cells carry oxygen bound to hemoglobin molecules.
Myoglobin is synthesized in the muscles.

59. Oxygen Use and Debt
When skeletal muscles are used for a minute or more, anaerobic respiration is required.
When a person is exercising strenuously, oxygen is used mostly to synthesize ATP.
As lactic acid increases, an oxygen debt develops.
It may take several hours to convert lactic acid back into glucose.

60. Muscle Fatigue
Prolonged exercise may cause a muscle to become unable to contract.
Usually caused by lactic acid accumulation
Muscle cramps appear to be caused by changes in extracellular fluid.

61. Production of Heat
Most energy released in cellular respiration becomes heat.
Muscle tissue generates significant heat.
Blood transporting heat generated by muscle to other tissues helps maintain body temperature.

62. Muscle Responses
Muscle fiber will remain unresponsive until the threshold stimulus is applied.
Twitch: contractile response of a fiber to impulse
Two types of twitches:
Fatigue-resistant slow
Fatigable fast

63. Actions of Skeletal Muscles
Skeletal muscles cause unique movements based on:
The type of joint they attach to
Where the attachment points are
When a muscle appears to be at rest, its fibers still undergo muscle tone.

64. Origins and Insertions
Skeletal muscle usually fastens to an origin at a moveable joint.
The other end connects to an insertion on the other side of the joint.
There may be more than one origin or insertion.

65. Origins and Insertions
During a contraction, the insertion is pulled toward the origin.
Flexion: a decrease in the angle of a joint
Extension: increase in the angle of a joint

66. Skeletal Muscle Interactions
Skeletal muscles usually function in groups.
Prime movers contract to provide most of the desired movement.
Synergists work with a prime mover to make its action more effective.
Other muscles act as antagonists to prime movers.

67. Skeletal Muscle Interactions

68. The Musculoskeletal System: Physiology
Functions of the musculoskeletal system:
Movement and manipulation of the environment
Heat is a by-product.
Shivering
Protect structures under them