Connective Tissue

the 3 primary germ layers1. Ectoderm2. Endoderm3. Mesoderm These give rise to all the basic

tissues of the body

The four types of tissues.

Epithelial Connective Muscle Nerve

glandular epithelium & how is it classified A gland is one or more cells that

makes and secretes an aqueous fluid

Classified by: Site of product release – endocrine

or exocrine Relative number of cells forming the

gland – unicellular or multicellular

Glandular epithelium – made up of cells that produce secretions

endocrine glands, what they secrete & how do they do it

Ductless glands that produce hormones

Secretions include amino acids, proteins, glycoproteins, and steroids

“Stuff” goes directly into blood

exocrine glands, what they secrete & how do they do it

More numerous than endocrine glands Secrete their products onto body

surfaces (skin) or into body cavities Examples include mucous, sweat, oil,

and salivary glands The only important unicellular gland is

the goblet cell “stuff” goes through ducts Sebum from sebaceous gland secretes

acid mantle on skin surface to kill bacteria

the major types of connective tissue & some examples

Found throughout the body Connective tissue proper, cartilage,

bone, & blood All arise from the same stem cell

Endoderm becomes gastrointestinal tract, respiratory tract, endocrine glands and organs

Mesoderm becomes bones, cartilage, blood, muscles

Ectoderm becomes the nervous system and skin

the general functions of connective tissue

Binding and support, protection, insulation, and transportation

the common characteristics of connective tissue

Mesenchyme as their common tissue of origin

Varying degrees of vascularity Nonliving extracellular matrix,

consisting of ground substance and fibers

Collagen is the main protein of ct

the major structural elements of connective tissue

Ground substance – unstructured material that fills the space between cells

Fibers – collagen (fibrous), elastic (elastin), or reticular (fibrous)

types of cells you find in connective tissue & where you find them

Fibroblasts Chondroblasts Osteoblasts Hematopoietic stem cells Found in mesenchyme, derived from

mesenchymal stem cells

Fibroblast

Chondroblast

Osteoblast

Hematopoietic stem cells

the two types of loose connective tissue proper given & what characterizes them 1. Areolar connective tissue Gel-like matrix with all three

connective tissue fibers Fibroblasts, macrophages, mast cells,

and some white blood cells Wraps and cushions organs Widely distributed throughout the

body

Areolar connective tissue (loose)

Loose connective Tissue Proper2. Adipose connective tissue Matrix similar to areolar connective

tissue with closely packed adipocytes Reserves food stores, insulates

against heat loss, and supports and protects

Found under skin, around kidneys, within abdomen, and in breasts

Local fat deposits serve nutrient needs of highly active organs

Adipose connective tissue (loose)

the two types of dense connective tissue proper & what characterizes them

Regular Parallel collagen fibers with a few

elastic fibers Major cell type is fibroblasts Attaches muscles to bone or to other

muscles, and bone to bone Found in tendons, ligaments, and

aponeuroses

Dense Regular (tendons)

Dense connective tissue proper Irregular Irregularly arranged collagen fibers

with some elastic fibers Major cell type is fibroblasts Withstands tension in many directions

providing structural strength Found in the dermis, submucosa of

the digestive tract, and fibrous organ capsules

Dense irregular (fibrous dermis)

the 3 different types of cartilage: what they are made of, their functions & where you would find them

1. Hyaline cartilage2. Elastic cartilage3. Fibrocartilage cartilage

1. Hyaline Cartilage

Looks like jelly – does not heal and usually is cut out when injured with hope of gaining muscle to compensate for the loss

Chondrocytes lie in lacunae (a small space containing an osteocyte in bone or chondrocyte in cartilage)

Supports, reinforces, cushions, and resists compression

Hyaline cartilage

Forms the costal cartilage Found in embryonic skeleton, the end of

long bones, nose, trachea, and larynx

2. Elastic Cartilage

Similar to hyaline cartilage but with more elastic fibers

Maintains shape and structure while allowing flexibility

Supports external ear (pinna) and the epiglottis

Elastic cartilage has “little eyes”

3. Fibrocartilage cartilage Matrix similar to hyaline cartilage

but less firm with thick collagen fibers

Provides tensile strength and absorbs compression shock

Found in intervertebral discs, the pubic symphysis, and in discs of the knee joint

Fibrocartilage

the characteristics & functions of osseous tissue.

Hard, calcified matrix with collagen fibers found in bone

Osteocytes are found in lacunae and are well vascularized

Osseous Tissue

Osseous Tissue cont’d

Supports, protects, and provides levers for muscular action

Stores calcium, minerals, and fat Marrow inside bones is the site of

hematopoiesis Bones will change shape with

pressure: braces/jawbone, tight shoes/bunions, hammer toe

Bone marrow: 2 kinds

1. Red marrow – site of hematopoiesis2. Yellow marrow – fat (this is why you

make soup from bones)

hematopoietic bone marrow of flat bones vertebrae, sternum, ribs, iliac. It represents 4-6% of body weight.

The fatty degeneration of red bone marrow (RBM) (25%) into yellow bone marrow (YBM) (75%) is completed around age 21 years.

Red marrow

C hematopoietic tissue forming new blood cells.

Yellow marrow

the characteristics & functions of blood

Red (carry O2, CO2) and white cells (defense) in a fluid matrix (plasma)

Contained within blood vessels Functions in the transport of

respiratory gases, nutrients, and wastes

Blood