Histology (Ch. 4) Flashcards
Four Categories of tissue
Epithelial
Connective
Nervous
Muscular
Organ Definition
A structure with descrete boundaries that is composed of two or more tissue types
Histology
the study of tissues and how they are arranged into organs
Epithelial
Tissues composed of layers of closely spaced cells that cover organ surfaces from glands, and serve protection, secretion, and absorption.
Connective
Tissue with usually more matrix than cell volume, often specialized to support, bind and protect organs.
Nervous
Tissues containing excitable cells specialized for more rapid transmission of coded information to other cells.
Muscular
Tissue composed of elongated, excitable muscle cells specialized for contraction.
3 primary germ layers
Ectoderm- (Gives rise to epidermis)
Endoderm (gives rise to mucous membrane lining digestive and respiratory tracts, digestive glands, among other things.)
Mesoderm (becomes gelatinous tissue called mesenchyme. (muscle bone and blood)
Simple squamos epithelium
single layer of flat ells
Allows materials to pass by diffusion and filtration in sites where protectionis not important. Secretes lubricating substances in serosae
In Kidney glomeruli, air sacs of lungs, lining of heart, blood vessels, and lymphatic vessels, lining of ventral body cavity (Serosae)
Simple cuboidal epithelium
Single layer of cubeliike cells
secrete abd absorb
kidney tubules; ducts and secretory portions of small glands; ovary surface
Simple Columnar epithelium
Single layer tall cells
absorbs; secretion of mucus, enzymes and other substances; ciliated type propels mucus by ciliary action
nonciliated located in lining of digestive tract, gall bladder, and excretory glands. Ciliated in small bronchi, uterine tubes, and some regions of the uterus.
pseudostratified columnar epithelium
single layer of cells differing in height.
secrete substances particularly mucus.
propel mucus by ciliary.
nonciliated: sperm ducts, large gland ducts,
Ciliated: trachea, most of upper resp.
Stratified squamos epithelium
thick membrane. basal cells are cuboidal or columnar. surface is always pushed up by younger cells.
protects underlying layers in areas of abrasion.
Nonkeritinized: in lining of mouth, esophogus and vagina.
Keratinized form skin
stratified cuboidal epithelium
rare. two layers cuboidal. sweat and mammary glands
stratified columnar epithilium
limited displacement. pharynx, urethra, gland ducts, transition areas.
Glandular epithilium
unicellular glands scattered b/w epithelial sheets.
connective tissues
common origin: mesenchyme. vascularity.
matrix allows connective tissue to bear weight.
Loose connective tissue (LCT)
areolar
adipose
reticular
Areolar
fibroblasts. gel-like matrix. wraps, cushions organs under epithelium. packages organ, surrounds capillaries
Adipose
closely packed fat cells. provide food fuel reserves.
support and protect organs in under skin, around eyeballs, kidneys abdomen and breasts.
Reticular
Loose network reticular fibers.
form soft internal skeleton (stroma) that supports other cell types. in lymphoid organs.
Dense Connective Tissue
Regular
irregular
elastic
Regular (DCT)
parallel collagen fibers. Few elastic fibers. Attaches muscle to bone. Tendons, ligaments,
Irregular
Irregularly arranged collagen fibers. some elastic. withstands tensions. in fibrous joint capsules. digestive tract.
