Connective Tissue Subgroups Dense Connective Tissue: Tendons and Ligaments Marked by a regular arrangement of tightly packed protein fibers, ligaments (connecting bone to bone in a joint) have tough collagen combined with flexible elastin fibers. Tendons (connecting muscle to bone) are bright white bands primarily composed of collagen.

Connective Tissue Subgroups Dense Connective Tissue: Cartilage Cartilage is composed of large round cells with spherical nuclei called chondrocytes, enclosed in tiny cavities called lacunae. The 3 types of cartilage (elastic, hyaline, and fibrocartilage) contain differing amounts of collagen and elastin within the matrix, resulting in varying levels of flexibility and/or strength.

muscular tissue Primary Functions Characteristics Cell Types Location Bone movement Facial expressions Propel blood through the heart and blood vessels Propel substances through the digestive system Characteristics Highly cellular, well-vascularized tissues Responsible for movement of the body Cell Types Muscle cells are called muscle fibers skeletal muscle Cardiac muscle Smooth muscle Location In all muscles All organs

Muscle Tissue: 3 Types Muscle Tissue enables the movement of body structures. Smooth, Cardiac, Skeletal

Muscle Types: Smooth Muscle Smooth muscle is non-striated, and acts in a number of involuntary processes in the body. elongated, tapering and non-striated cells

Muscle Types: Smooth Muscle allows the expansion and contraction of arteries and veins lines the bladder and reproductive tracts lines the entire gastrointestinal tract

Did you know?... Tiny smooth muscle fibers in the skin called Arrector pili are responsible for “goose bumps.”

Muscle Types: Cardiac Muscle Cardiac muscle (heart muscle) is striated but functions involuntarily. It is solely responsible for propelling blood throughout the body. Nucleus positioned in the center of the cell.

Muscle Types: Skeletal Muscle Skeletal muscle is striated, and associated with voluntary movement. It also provides structure and support for organs and tissues. Nucleus is located in the periphery of the cell.

Anatomy of skeletal muscles Skeletal muscle fiber (cell) tendon Muscle Fascicle Skeletal muscle Skeletal muscle fiber (cell)

How Do Muscles Work? 3 step process: Individual muscle fibers are composed of small cylindrical structures called myofibrils. The functional component within the myofibril is called the sarcomere. Within the sacromere, protein filaments called actin and myosin allow the cell to expand and contract in a 3 step process:

3 Steps 1) Before the muscle is stimulated, actin and myosin filaments partially overlap one another. 2) A nerve cell releases a signal which causes the actin and myosin filaments to “slide” along one another and overlap even more. 3) This contracts the myofibril and subsequently the entire muscle cell. When the nervous signal changes, the filaments relax and return to their original state.

myofibril Muscle fiber sarcomere Z-line Actin myosin Myosin molecule of thick myofilament Thin myofilament

Sarcomere