Chapter 4 Section- B A&P 1

what tissue is the most abundant and widely distributed tissue in the body?

Connective tissue

Connective tissue consists of two basic elements:

1. cells

2. Extracellular Matrix (formed from ground substance and protein fibers)

abundant with relatively few cells and tends to prevent tissue cells from touching one another.

Matrix

Cells in connective tissue are derived from

mesenchyme

Immature cells have names that end in

-blast ( e.g., fibroblast, chondroblast)

Mature cells have names that end in

-cyte (e.g., osteocyte).

Fibroblasts

secrete fibers and matrix

Macrophages

• Histiocytes

• develop from monocytes

• are phagocytic

Plasma cells

• develop into antibody producing lymphocytes

• B-cells

Mast cells

• abundant along side blood vessels

• Produce histamine

Adipocytes

• fat cells

• stores energy in form of fat

Leukocytes

• white blood cells

Substance found in the ground substance include:

1. hyaluronic acid

2. chondroitin sulfate

3. dermatan sulfate

4. keratan sulfate

Collectively called glycosaminoglycan (GAGs)

The function of ground substance is that it:

1. supports

2. binds

3. provides a medium for the exchange of materials between the blood and cells

4. Active in influencing cell functions

Collagen fibers

1. composed of the protein collagen

2. are very tough and resistant to stretching

3. allow some flexibility in tissue

Collagen fibers are found in

1. Bone

2. cartilage

3. Tendons

4. ligaments

Elastic Fibers

1. Composed of the protein elastin

2. Provide strength and stretching capacity

Elastic Fibers are found in:

1. Skin

2. Blood vessels

3. Lungs

Reticular fibers

1. Consisting of collagen and glycoprotein

2. provide support in the walls of blood vessels

Reticular fibers form a strong, supporting network around

1. Areolar connective tissue

2. fat cells

3. nerve fibers

4. smooth muscle fibers

Connective tissue that is present primarily in the embryo or fetus is called

embryonic connective tissue

Mesenchyme

• found almost exclusively in the embryo

is the tissue form from which all other connective tissue eventually arises

Mucous

found in the umbilical cord of the fetus

Classification of connective tissues:

1. Mature

2. Loose

3. Dense

4. Cartilage

5. Bone

6. Blood

Loose

1. Consist of all three types of fibers

2. several types of cells

3. a semifluid ground substance

Dense

1. contains more numerous, thicker, and dense fibers

2. considerably fewer cells than loose connective tissue

Cartilage

1. consists of a dense network of collagen fibers

2. elastic fibers embedded in chondroitin sulfate

Bone

1. consists of a matrix containing mineral salts and collagenous fibers

2. cells called osteocytes

Blood

1. consists of a liquid matrix called plasma and formed elements

Areolar connective tissue is a prime example of loose connective tissue.

1. The ground substance aids the passage of nutrients from the blood vessels of the connective tissue into adjacent cells and tissues.

2. It is found in the subcutaneous layer.

Membranes

flat sheets of pliable tissue that cover or line a part of the body

2 types of membrane

1. Epithelial membranes consist of an epithelial layer and an underlying connective tissue layer and include mucous membranes, serous membranes, and the cutaneous membrane or skin.

2. Synovial membranes line joints and contain only connective tissue.

Mucous membranes (mucosa)

line cavities that open to the exterior, such as the gastrointestinal tract

Synovial membranes

line joint cavities, bursae, and tendon

sheaths and do not contain epithelium; they also secrete a

lubricating synovial fluid

Muscle tissue consists of

fibers that provide motion, maintain posture, and produce heat

Two kinds of cells

1. Neurons- nerve cells

2. neuroglia- protective and supportive

Neuroglia

protect and support neurons

neurons

carry sensory and motor information and perform integrative functions.

neurons and muscle fibers are considered excitable cells because

they exhibit electrical excitability

Electrical excitability

is the ability to respond to certain stimuli by producing electrical signals, such as action potentials, which travel along the plasma membrane of a neuron or muscle fiber due to the presence of specific voltage-gated channels

Tissue repair

the process that replaces worn out, damaged, or dead cells.

Younger bodies generally experience:

1. Tissue repairs rapidly and efficiently

2. A better nutritional state

3. A better blood supply to tissues

4. A father metabolic rate

5. Aging slows the process of tissue repair

Lupus

inflammatory disease of connective tissue