Ch. 5 Histology Flashcards
Tissue
collection of similar cells grouped together to function as unit
- different tissues associate with each other to form organ
- each type of tissue performs function for body such as protection, contraction, or secretion
Four types of tissues
- epithelial tissue
- connective tissue
- muscular tissue
- nervous tissue
Epithelial tissue
covers body surface, covers and lines internal organs, and forms glands
- function: protection, absorption, and secretion
- cells are tightly packed together, forming layers and sheets
- apical surface, basement membrane, basal surface
- avascular
- name depends on number of layers and shape of individual cells
Apical surface
has a free or exposed surface
Basal surface
sits on basement membrane
Avascular
does not have direct blood supply
Simple squamous epithelium
single layer of flat cells
- forms thin and delicate membranes
- allows for easy movement of molecules across membrane through osmosis and diffusion
- found in kidney glomeruli, alveoli of the lungs, lining of the heart, blood vessels and lymphatic vessels, and serous membranes
Simple cuboidal epithelium
single layer of cube-shaped cells
- secretion and absorption
- found in kidney tubules, small ducts and glands, and covering the ovary
Simple columnar epithelium
single layer of column-shaped cells
- absorption and secretion
- lines most of the digestive tract, gallbladder, ducts of large glands, small bronchi, and uterine tubes
- digestive tract lining possess microvilli
- uterus and bronchi are lined with cilia
Microvilli
short slender cell processes that increase the surface area available for absorption of nutrients
Cilia
hair-like; propel substances
Pseudostratified columnar epithelium
cell oriented in a single layer of tightly packed cells of different heights
- tissue appears stratified
- lines the trachea and most of the upper respiratory tract
- contains goblet cells that secrete mucus and cilia that sweep mucus up and out of the airways
- lines reproductive ducts and ducts of large glands
Goblet cells
secrete mucus
Stratified squamous epithelium, keratinized
many layers of flat cells
- deepest layers are almost cuboidal in shape and divide
- cells become flatter as they pushed toward the surface by newer cells
- upper layers are dead and filled with keratin (protection)
- found in epidermis of skin
Keratin
a hard protein
Stratified squamous epithelium, non-keratinized
same as keratinized stratified squamous epithelium
- except upper layers of cells do not die and do not become filled with keratin
- contain visible nuclei
- protect underlying tissues
- found in lining of the esophagus, vagina, mouth and anus
Transitional epithelium
a stratified tissue
- apical layers of cells are larger and rounder
- cells allow stretching of the tissue layer
- bladder fills and the cells change from rounded to flattened shape
- lining the urinary bladder, ureters, and the urethra and allows distension of these organs
Connective tissue
bind, support, protect, and fill spaces
- most abundant type of tissue in the body
- fewer cells which are spread apart
- two types: connective tissue paper and specialized connective tissue
- matrix (fibers and ground substances)
- rich blood supply
Matrix
non-cellular, non-living, and consists of fibers and ground substance
- space between the cells
- a substance produced and secreted by the connective tissue cells
Fibers types
collagen, elastic and reticular
Ground substance
vary in consistency from watery to gel-like solid
Areolar (Loose) connective tissue
gel-like matrix with collagen and elastic fibers
- cells include fibroblasts, mast cells, and macrophages
- forms a layer to which epithelial cells may bind, as in the papillary layer of the dermis
- found around capillary networks where it binds and protects the capillaries
Reticular connective tissue
matrix consists of reticular fibers arranged in a network and loose ground substance
- main cell type in reticular cells
- flexible internal scaffolding supports other types of cells
- found in lymph nodes, spleen, and bone marrow
Dense irregular connective tissue
matrix consists of bundles of collagen fibers and little ground substance
- collagen bundles give tissue structural strength
- main cell type is a fibroblast
- found in reticular layer of dermis, wall of digestive tract, and fibrous capsules of organs and joints
Dense regular connective tissue
matrix contains parallel bundles of collagen fibers and little ground substance
- parallel arrangement of collagen bundles gives tissue great tensile strength
- main cell type is a fibroblast
- forms ligaments and tendons, tensile strength anchor bones to each other and muscles to bone
