Lecture 2
The Tissue Level of
Organization
Atinga Ba-Etilayoo
UENR, NURSING.
,What is a Tissue?
◼ A tissue is a group of cells
❑ Common embryonic origin
❑ Function together to carry out specialized activities
❑ Factors that infl. Fxns & properties: nature of the
extracellular material & connections between the
cells
◼ Hard (bone), semisolid (fat), or liquid (blood)
◼ Histology is the science that deals with the
study of tissues.
◼ Pathologist specialized in laboratory studies
of cells and tissue for diagnoses
UENR, NURSING.
,4 Types of Tissues
❑ Epithelial
◼ Covers body surfaces and lines hollow organs,
body cavities, duct, and forms glands
❑ Connective
◼ Protects, supports, and binds organs.
◼ Stores energy as fat, provides immunity
❑ Muscular
◼ Generates the physical force needed to make body
structures move and generate body heat
❑ Nervous
◼ Detect changes in body and responds by
generating nerve impulses
UENR, NURSING.
, Development of Tissues
◼ Tissues of the body develop from three primary
germ layers:
◼ Ectoderm, Endoderm, and Mesoderm
❑ Epithelial tissues develop from all three germ
layers
❑ All connective tissue and most muscle tissues
drive from mesoderm
❑ Nervous tissue develops from ectoderm
UENR, NURSING.
The Tissue Level of
Organization
Atinga Ba-Etilayoo
UENR, NURSING.
,What is a Tissue?
◼ A tissue is a group of cells
❑ Common embryonic origin
❑ Function together to carry out specialized activities
❑ Factors that infl. Fxns & properties: nature of the
extracellular material & connections between the
cells
◼ Hard (bone), semisolid (fat), or liquid (blood)
◼ Histology is the science that deals with the
study of tissues.
◼ Pathologist specialized in laboratory studies
of cells and tissue for diagnoses
UENR, NURSING.
,4 Types of Tissues
❑ Epithelial
◼ Covers body surfaces and lines hollow organs,
body cavities, duct, and forms glands
❑ Connective
◼ Protects, supports, and binds organs.
◼ Stores energy as fat, provides immunity
❑ Muscular
◼ Generates the physical force needed to make body
structures move and generate body heat
❑ Nervous
◼ Detect changes in body and responds by
generating nerve impulses
UENR, NURSING.
, Development of Tissues
◼ Tissues of the body develop from three primary
germ layers:
◼ Ectoderm, Endoderm, and Mesoderm
❑ Epithelial tissues develop from all three germ
layers
❑ All connective tissue and most muscle tissues
drive from mesoderm
❑ Nervous tissue develops from ectoderm
UENR, NURSING.
