Connective Tissue SubgroupsDense 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 SubgroupsDense 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 tissuemuscular tissueCharacteristics

Highly cellular, well-vascularized tissues

Responsible for movement of the body

Cell Types Muscle cells are calledmuscle fibers skeletal muscle Cardiac muscle Smooth muscle

Location In all muscles All organs

Primary Functions Bone movement Facial expressions Propel blood through

the heart and blood vessels

Propel substances through the digestive system

Muscle Tissue: 3 TypesMuscle Tissue enables the movement

of body structures. Smooth, Cardiac, Skeletal

Muscle Types: Smooth MuscleSmooth muscle is

non-striated, and acts in a number of involuntary processes in the body.

elongated, tapering and non-striated cells

Muscle Types: Smooth Muscleallows the expansion and contraction of

arteries and veinslines the bladder and reproductive tractslines 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 MuscleCardiac 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 MuscleSkeletal 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)

Muscle Fascicle

Skeletal muscle

tendon

How Do Muscles Work?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.

Muscle fiber

myofibril

Actin myosin

Thin myofilamentMyosin molecule ofthick myofilament

sarcomere

Z-line

Sarcomere