CH 38 The Musculoskeletal System

Musculoskeletal system

General function is to cause or control movement, more specifically: Support & maintain upright posture. It ALSO allows movement such as body transport & manipulates objects. AND lastly to PROTECT! What body system is this?

Hydrostatic pressure

1. Refers to the pressure that any fluid in a confined space exerts. Formed by a fluid-filled compartment within the body, called the coelom.

Compartment is under ____ because of the fluid, and supports the other organs of the organism.

Found in soft-bodied animals such as sea anemones, earthworms, Cnidaria, and other invertebrates.

Exoskeleton

consists of a hard encasement on the surface of an organism. Provides defense against predators, supports the body, and allows for movement through the contraction of attached muscles.

• Arthropods such as crabs and lobsters have it & consists of 30–50% chitin, a polysaccharide derivative of glucose that is a strong but flexible material.

  Because it’s acellular, arthropods must

  periodically shed their exoskeletons because it does not grow as the organism grows.

Endoskeleton

• Consists of hard, mineralized structures located within the soft

  tissue of organisms. They provide support for the body, protect internal organs, and allow for movement through contraction of

  muscles attached to the skeleton.

huma axial skeleton

skeleton consists of the bones of the skull, ossicles of the middle ear, hyoid bone, vertebral column, and rib cage.

skull

bones support the structures of the face and protect the brain.

cranial bones

Includes the frontal, parietal, and sphenoid bones which cover the top of the head. They are the facial bones of the skull from the face and provide cavities for the eyes, nose, and mouth.

appendicular skeleton

this skeleton is composed of the bones of the pectoral limbs (arm, forearm, hand), the pelvic limbs (thigh, leg, foot), the pectoral girdle, and the pelvic girdle.

upper limbs

consists of the humerus of the upper arm, the radius and ulna of the forearm, eight bones of the carpus, five bones of the metacarpus, and 14 bones of the phalanges.

Pevic girdle

• To adapt to reproductive fitness, the (a) female pelvis is lighter,

  wider, shallower, and has a broader angle between the pubic

  bones than (b) the male pelvis.

Long bone

• (a) Longer than wide

• (b) Shaft with two ends

• (c) Mostly compact

• (d) Bones of limbs

• is covered by articular cartilage at either end and contains

  bone marrow (shown in yellow in this illustration) in the marrow cavity.

  What type of bone is this?

Short bone

• (a) Cube-like

• (b) Mostly spongy

• (c) Sesamoid—bones embedded in tendon

• Patella

  What type of bone is this?

Flat bone

(a) Spongy bone embedded within parallel layers of thin compact bone

Irregular bone

• (a) Vertebrae and hip bones

• (b) Complicated shapes

• (c) Mostly spongy with a thin covering of compact bone

  What type of bone is this?

Lacunae:

cavities containing osteocytes

Canaliculi:

connect lacunae to each other and central canal

Trabeculae:

needle-like (flat) pieces

• appear less organized than structures of

  compact bone

  (a) No osteon

  (b) Organization is based on lines of stress

  (c) Lamella and osteocytes are irregularly organized

endochondrial ossification

Cartilage bone are used as a pattern for bone construction

(a) Primary ossification center at the center of the hyaline cartilage

intramembranous ossification

Ossification center forms in fibrous connective tissue membrane

Mesenchymal cells differentiate into osteoblasts

fibrous joints

are held together by fibrous connective tissue.

Cartilaginous joints

are joints in which the bones are connected by cartilage.

Synchondrosis

• the bones are joined by hyaline cartilage & are found in the epiphyseal plates of growing bones in children.

Symphyses

• hyaline cartilage covers the end of the bone but the

  connection between bones occurs through fibrocartilage. They are found at the joints between vertebrae. Either type of

  cartilaginous joint allows for very little movement.

synovial joints

• are the only joints that have a space or “synovial cavity” in the joint. The cavity is filled with synovial fluid, which

  lubricates the joint.

planar joints

The joints of the carpal bones in the wrist are examples of?

hinge joint

The elbow joint, where the radius articulates with the humerus, is an example of a?

pivot joint

The joint in the neck (between the C1 and C2 vertebrae) that allows the head to move back and forth is an example of a?

condyloid joints

The metacarpophalangeal or joints between the radius & carpal bones of the wrist in the finger are examples of?

saddle joints

The carpometacarpal joints in the thumb are examples of?

ball-and-socket joint

The shoulder joint or hip joint is an example of a ?

smooth muscle

cells are short, tapered at each end, and have only one plump nucleus in each. Involuntary

cardiac muscle

cells are branched and striated, but short. The cytoplasm may branch, and they have one nucleus in the center of the cell. Involuntary

skeletal muscle

• surrounded by a plasma membrane called the sarcolemma with a cytoplasm called the sarcoplasm. A muscle fiber is composed of many fibrils, packaged into orderly units. Multinucleated, voluntary & striated