Chapter 4 - Tissues Flashcards
Collections of specialized cells and the extracellular substances surrounding them
Tissues
Body tissues are classified into:
4 types
structure of the cells
composition of the noncellular substances surrounding the cells (called
the extracellular matrix)
functions of the cells
The four primary tissue types:
epithelial tissue
connective tissue
muscle tissue
nervous tissue
the microscopic study of tissues
Histology
the process of removing
tissue samples from patients surgically or with a needle for diagnostic purposes.
biopsy
an examination of the organs of a
dead body to determine the cause of death or to study the changes caused by a disease.
autopsy
-blast means?
bud or germ
Approximately 13 or 14 days after fertilization, the embryonic stem cells that give rise to a new individual form a slightly elongated disk
consisting of two layers:
epiblast
hypoblast
Cells of the epiblast then migrate
between the two layers to form the three embryonic germ layers:
ectoderm
mesoderm
endoderm
give rise to all the tissues of the body
The germ layers
the inner layer, forms the lining
of the digestive tract and its derivatives.
endoderm
the middle layer, forms tissues such as muscle, bone, and blood vessels
mesoderm
the outer layer, forms the skin.
ectoderm
the portion of the ectoderm called __ becomes the nervous system
neuroectoderm
the groups of cells that break away from the neuroectoderm during development that give rise to parts of the peripheral nerves, skin pigment, the medulla of the adrenal gland, and many tissues of the face.
neural crest cells
covers and protects surfaces, both outside and inside the body
Epithelial tissue, or epithelium
characteristics common to most types of epithelial tissue:
- Mostly composed of cells.
- Covers body surfaces.
- Distinct cell surfaces.
- Cell and matrix connections.
- Nonvascular.
- Capable of regeneration.
where cells are exposed and not
attached to other cells.
free, or apical surface
where cells are attached to other epithelial cells.
lateral surface
attached to a basement membrane.
basal surface
often lines the lumen of ducts, vessels, and cavities.
free surface
a specialized type of extracellular material secreted by epithelial and connective tissue cells.
basement membrane
Functions of Epithelial Tissues:
- Protecting underlying structures.
- Acting as a barrier.
- Permitting the passage of substances.
- Secreting substances.
- Absorbing substances.
Classification of Epithelial Tissues based on the number of cell layers in each:
- Simple epithelium
- Stratified epithelium
- Pseudostratified columnar epithelium