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
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
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