MUSCLE.

Muscle (from Latin musculus, diminutive of mus "mouse"^[1]) is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to produce force and cause motion. Muscles can cause either locomotion of the organism itself or movement of internal organs. Cardiac and smooth muscle contraction occurs without conscious thought and is necessary for survival. Examples are the contraction of the heart and peristalsis which pushes food through the digestive system. Voluntary contraction of the skeletal muscles is used to move the body and can be finely controlled. Examples are movements of the eye, or gross movements like the quadriceps muscle of the thigh. There are two broad types of voluntary muscle fibers: slow twitch and fast twitch. Slow twitch fibers contract for long periods of time but with little force while fast twitch fibers contract quickly and powerfully but fatigue very rapidly.
Muscles are predominately powered by the oxidation of fats and carbohydrates, but anaerobic chemical reactions are also used, particularly by fast twitch fibers. These chemical reactions produce adenosine triphosphate (ATP) molecules which are used to power the movement of the myosin heads.

Reference:
www.wikipedia.com

Bone growth !!!!!

Intramembranous ossification mainly occurs during formation of the flat bones of the skull but also the mandible, maxilla, and clavicles; the bone is formed from connective tissue such as mesenchyme tissue rather than from cartilage. The steps in intramembranous ossification are:

1. Development of ossification center
2. Calcification
3. Formation of trabeculae
4. Development of periosteum

[edit] Endochondral ossification

Endochondral ossification

Endochondral ossification, on the other hand, occurs in long bones and most of the rest of the bones in the body; it involves an initial hyaline cartilage that continues to grow. The steps in endochondral ossification are:

1. Development of cartilage model
2. Growth of cartilage model
3. Development of the primary ossification center
4. Development of the secondary ossification center
5. Formation of articular cartilage and epiphyseal plate

Endochondral ossification begins with points in the cartilage called "primary ossification centers." They mostly appear during fetal development, though a few short bones begin their primary ossification after birth. They are responsible for the formation of the diaphyses of long bones, short bones and certain parts of irregular bones. Secondary ossification occurs after birth, and forms the epiphyses of long bones and the extremities of irregular and flat bones. The diaphysis and both epiphyses of a long bone are separated by a growing zone of cartilage (the epiphyseal plate). When the child reaches skeletal maturity (18 to 25 years of age), all of the cartilage is replaced by bone, fusing the diaphysis and both epiphyses together (epiphyseal closure).

Reference:
www.wikipedia.com

LONG BONE.

Long bones are characterized by a shaft, the diaphysis, that is much longer than it is wide. They are made up mostly of compact bone, with lesser amounts of marrow, located within the medullary cavity, and spongy bone. Most bones of the limbs, including those of the fingers and toes, are long bones. The exceptions are those of the wrist, ankle an d kneecap.
Reference:
www.wikipedia.org

Bone Tissue

BONE TISSUE
Bone tissue is a specialized form of connective tissue and is the main element of the skeletal tissues. It is composed of cells and an extracellular matrix in which fibers are embedded. Bone tissue is unlike other connective tissues in that the extracellular matrix becomes calcified.
FUNCTIONS OF BONE TISSUE

• The skeleton is built of bone tissue. Bone provides the internal support of the body and provides sites of attachment of tendons and muscles, essential for locomotion.
• Bone provides protection for the vital organs of the body: the skull protects the brain; the ribs protect the heart and lungs.
• The hematopoietic bone marrow is protected by the surrounding bony tissue.
• The main store of calcium and phosphate is in bone. Bone has several metabolic functions especially in calcium homeostasis.

Bone is a hard, but brittle, tissue and is relatively light per unit volume. Bone is a dynamic tissue, which throughout life bone tissue is continually being formed and resorbed. This remodelling and reorganization of bone tissue is the result of many factors including:

• mechanical stimuli
• metabolic causes (lack of dietary calcium, illness, aging)
• endocrine changes
• effects of drugs.

MACROSCOPIC STRUCTURE OF BONE
There are two main categories of bone :

• Spongy bone (trabecular bone, cancellous bone)
• Compact bone (cortical bone)

Spongy bone
Spongy bone is composed of a lattice or network of branching bone spicules or trabeculae. The spaces between the bone spicules contain bone marrow.
Compact bone
Compact bone appears as a mass of bony tissue lacking spaces visible to the unaided eye

Reference:
www.technion.ac.il

SMALL AND LARGE INTESTINE TISSUE!

Reference: http://www.blessedherbs.com/

INTESTINE! Outer wall.

The serosa consists of ordinary loose fibrous connective tissue with a delicate covering of mesothelium (simple squamous epithelium derived from mesoderm).  The serosa is continuous with the mesentery.

Reference: www. siumed.edu