Cells: fibroblasts (synthetic fibers and matrix), macrophages (phagocytosis defense), plasma cells (secreting antibodies), mast cells (involving in allergies), etc.

Fiber: collagen fibers (strong and tough, containing collagen), elastic fibers (giving elasticity), and mesh fibers (supporting, mostly distributed in organs such as hematopoiesis).

Matrix: proteoglycans, fibronectin, etc., constitute the tissue liquid microenvironment.

Regular dense connective tissue: a large number of collagen fibers arranged in parallel, such as tendons, have strong tensile resistance and few cells, mainly tensocytes.

Irregular dense connective tissue: collagen fibers interwoven into a web, such as the dermis, adapt to multi-directional stress, containing fibroblasts, etc.

White adipose tissue: monovesicular adipocytes accumulate, store energy, keep heat and buffer, and are widely distributed in the subcutaneous and around the internal organs.

Brown adipose tissue: polyvesicular adipocytes, rich in mitochondria, produce heat, and are more common in neonates and hibernating animals.

Reticular cells: Multiple protrusions, producing reticular fibers that attach to them.

Reticular fibers: interwoven into a net, providing stents for hematopoietic and lymphatic organs, such as bone marrow and lymph nodes.

Features: The matrix contains a lot of moisture and is translucent. The fibers are collagenic fibers, which are fine and difficult to distinguish.

Distribution: articular surface, rib cartilage, respiratory cartilage, etc., which plays a supporting and reduce friction.

Cells: Chondrocytes are located in the cartilage fossa, and the peripheral cells are naive and mature in the center.

Fiber: contains a large amount of elastic fibers and has strong elasticity.

Distribution: auricle, epiglottis, etc., to adapt to deformation while maintaining the shape.

Fiber: A large number of collagen fiber bundles, arranged in parallel or interlaced, with strong toughness.

Distribution: intervertebral discs, articular discs, etc., withstand pressure and buffer shock.

Organic ingredients: collagen fibers (accounting for 90%, providing toughness), non-collagens such as osteocalcin (involving in calcium salt deposition, etc.).

Inorganic components: hydroxyapatite crystallizes, making the bones hard, and calcium and phosphorus are the main elements.

Osteoprogenitor cells: Stem cells that can differentiate into osteoblasts.

Osteoblasts: Synthesize and secrete bone matrix, which promotes the deposition of calcium salts and forms bone.

Osteocytes: Cells in mature bone tissue have slender protrusions to maintain bone metabolism balance.

Osteoclasts: multinucleated giant cells, dissolve and absorb bones, and reshape bones.

Annular bone plate: The outer ring bone plate is thick, the inner ring bone plate is thin, and has a through-pipe tube connecting the inside and outside, which can nourish and transport substances.

Bone unit (Havers system): Bone plates arranged in the central tube and the surrounding multi-layer concentric circles are the basic structural units of the backbone.

Interbone plate: Remaining of old bone units, filled between bone units.

Trabecula: needle-shaped or sheet-shaped, composed of bone plates and bone cells, interwoven into a net, with a bone marrow cavity between them, which produces hematopoiesis and reduces bone weight.

Water: accounts for more than 90%, and the solvent acts.

Plasma protein: albumin (maintaining colloidal osmotic pressure), globulin (immunity, transportation, etc.), fibrinogen (coagulation), etc.

Electrolytes, nutrients, metabolites, hormones, etc.: Maintain internal environmental steady state and material transportation.

Red blood cells: double concave disc-shaped, containing hemoglobin, transports oxygen and carbon dioxide, and has no nucleus and organelles.

leukocyte:

Platelets: No nucleus, containing organelles, participate in coagulation, stop bleeding, and repair vascular endothelium.