Ch. 4 Part 3

Connective tissues

Connective Tissue

• Most abundant and widely distributed tissues in the body

• Functions:– Binds together, supports and strengthens other body

tissues– Protects and insulates internal organs– Compartmentalizes structures such as skeletal muscles– Serves as major transport system within the body– Primary location of stored energy reserves– Main source of immune responses

Connective Tissue

• Consists of 2 basic elements• Extracellular matrix– Material located between its widely spaced cells– Consists of protein fibers and ground substance– Usually determines characteristics (ex: bone –

hard and inflexible)• Cells

Connective Tissue Cells

• Vocab– Blast = to bud or sprout (immature cells)• Fibroblast, chondroblast, osteoblast

– Cyte (mature cells)• Chondrocyte, osteocyte

- “blast gives rise to cyte”

Connective Tissue Cells

• Macrophages– Irregular shape with short branches– Where: wandering and fixed (lungs, spleen)– Function: engulf bacteria and cellular debris

• Fibroblasts– Large, flat cells with branches– Where: several types of tissue– Function: migrate through C. T. secreting fibers

Connective Tissue Cells

• Plasma cells– Small– Where: most places, especially gastrointestinal

and respiratory tracts– Function: secrete antibodies for immune response

• Mast cells– Where: alongside blood vessels– Function: produce histamine for inflammatory

response; can bind to and kill bacteria

Connective Tissue Cells

• Adipocytes– Also called fat or adipose cells– Where: deep to skin and around organs– Function: store triglycerides (fats) as energy

• White blood cells– Not normally in C. T. but can migrate there in

response to infection

Connective Tissue Cells

Checkpoint

• In what ways do connective tissues differ from epithelia?

• What are the features of the cells of connective tissue?

Extracellular Matrix

• Two major components• Ground substance– Component of C. T. between cells and fibers

• Fibers– Collagen fibers, elastic fibers, reticular fibers

Connective Tissue Types

• Embryonic – we will not study• Mature – we will study– Loose• Areolar, adipose

– Dense– Cartilage• Hyaline, fibrocartilage, elastic

– Bone– Liquid• Blood

Mature Connective Tissue Types• Areolar C. T.

– Contains: fibroblasts, macrophages, plasma cells, mast cells, adipocytes, white blood cells, collagen fibers, elastic fibers, and reticular fibers

– Where: form subcutaneous layer – attaches skin to underlying tissues

• Adipose– Single cells filled up with single, large triglyceride droplet– Cytoplasm and nucleus pushed aside– Found everywhere areolar is found– Requires blood flow – heavier = more blood vessels = high blood

pressure

Areolar Adipose

Mature Connective Tissue Types

• Cartilage– Collagen and elastic fibers in a gel-like substance– Can endure stress– Chondrocytes – mature cartilage cells; occur singly

or in groups within lacunae– Has no blood supply – heals poorly after injury– 3 types – hyaline, fibrocartilage, and elastic

Cartilage

Mature Connective Tissue Types

• Bone– Also called osseous tissue– Includes marrow, endosteum, periosteum– Basic unit of compact bone is osteon or Haversian

system• Blood– Consists of: plasma, red blood cells, white blood

cells, platelets

Bone Blood

Checkpoint

• Describe the following:– Areolar connective tissue– Adipose tissue– Cartilage– Bone tissue– Blood tissue