108
Classification Based on Function
- Mucous membrane produces mucus. It protects,
absorbs- nutrients, and secretes enzymes and bile
salts in addition to mucus.^
- Simple exocrine glands such as sweat and seba-
ceous glands have single unbranching ducts.^
- Compound exocrine glands are made of several
branching lobules with branching ducts. Examples are
the mammary glands and the large salivary glands.^
- Endocrine glands are ductless and secrete
hormones- directly into the bloodstream.^
- Endothelium lines the blood and lymphatic vessels-.
The endothelium of the heart is called the
endocardium.^
- Mesothelium or serous tissue lines the great cavities-
of the body. The pleura lines the thoracic cavity. The
peritoneum lines the abdominal cavity. The
pericardium covers the heart.
Connective Tissue
- Connective tissue is made of cells with lots of
intercellular- material called matrix.^
- Fibers of tough collagen or fibers of flexible elastin
can be embedded in this matrix.^
- The three subgroups of connective tissue are loose
connective tissue, dense connective tissue, and
specialized- connective tissue.
Loose Connective Tissue
- The three types of loose connective tissue are
areolar,- adipose, and reticular.^
- Loose connective tissue fills space between and
penetrates into organs.^
- Areolar is the most widely distributed type of loose
connective tissue. It contains three types of cells:
fibroblasts, which make fibrils for repair; histiocytes
or macrophages, which do phagocytosis; and mast
cells, which produce the anticoagulant heparin and
histamine, an inflammatory substance.^
- Adipose tissue is loose connective tissue with fat
stored in its cells. It protects and insulates.^
- Reticular tissue forms the framework of the liver,
spleen, lymph nodes, and bone marrow.
Dense Connective Tissue
- Dense connective tissue having a regular arrange-
ment of embedded fibers are tendons, ligaments, and
aponeuroses.
Chapter 5- Dense connective tissue having an irregular
arrangement- of embedded fibers are muscle
sheaths, joint capsules, and fascia.
Specialized Connective Tissue- The cells of cartilage are called chondrocytes.
The three types of cartilage tissue are hyaline,
fibrocartilage,- and elastic.^ - Hyaline cartilage is found in the costal cartilages that
attach the ribs to the sternum, in the septum of our
nose, and in the rings that keep our trachea and
bronchi open.^ - Fibrocartilage is very strong; intervertebral disks are
made of fibrocartilage.^ - Elastic cartilage is easily stretched and flexible. It is
found in the ears, epiglottis, and auditory tubes.^ - The two types of bone tissue are compact or dense
and cancellous or spongy. Bone cells are called os-
teocytes. They are embedded in a matrix of calcium
and phosphorous, the mineral salts responsible for the
hardness of bone.^ - Our teeth are made of dentin; the crown of the tooth is
covered with enamel.^ - Blood is composed of a liquid portion called plasma
and the blood cells. Blood cells are formed in red bone
marrow, a hematopoietic tissue.^ - Lymphoid tissue makes up our lymph glands,
thymus, spleen, tonsils, and adenoids. This tissue
produces the plasma cells or B lymphocytes that
produce antibodies.^ - The reticuloendothelial (RE) system is involved in
phagocytosis in connective tissue. Kupffer’s cells
line the liver; RE cells also line the spleen and bone
marrow. Macrophage is a term for any phagocytic
cell of the RE system. Microglia cells do
phagocytosis in the nervous system; other
neuroglia- cells do support.^ - Synovial membranes line joints and bursae. They
produce synovial fluid, which lubricates joints and
nourishes cartilage.
Connective Tissue Functions1.^ It supports other tissues.^
2.^ It provides nourishment: blood carries nutrients.^
3. It transports: blood transports enzymes and
hormones.^
4.^ It connects various tissues to one another.^
5. It provides movement via bones.