Microscopes & Histology (LAB 3) Flashcards
scanning objective
4x magnification
low power objective
10x magnification (yellow)
high power dry objective
40x magnification (blue)
oil immersion objective
100x magnification (white) \> requires special technique & use of immersion oil
total magnification
power of ocular lens X power of objective lens
human body contains 4 main types of tissues:
- epithelial tissue
- connective tissue
- neural tissue
- muscular tissue
epithelial tissue
found on internal & external surfaces
all types are named according to 2 characteristics:
cell shape
number of layers of cells
simple squamous
single layer of flattened cells with disc-shaped central nuclei and sparse cytoplasm, simplest form of epithelia
function: allows materials to pass by diffusion and filtration in sites where protection isn’t important, secretes lubricating substances in serosae
location: kidney glomeruli, air sacs of lungs, lining of heart, blood vessels, and lymphatic vessels, lining of ventral body cavity (serosae)
simple cuboidal
single layer of cube-like cells with large, spherical central nuclei
function: secretion and absorption
location: kidney tubules, ducts and secretory portions of small glands, ovary surface
stratified squamous
thick membrane composed of several cell layers, basal cells are cuboidal or columnar and metabolically active, surface cells are keratinized and dead (squamous), basal cells are active in mitosis and produce cells of more superficial layers
function: protects underlying tissues in areas subjected to abrasion
location: non-keratinized type forms most linings of esophagus, mouth, and vagina, keratinized variety forms epidermis of skin, a dry membrane
simple columnar
single layer of tall cells with round to oval nuclei, many cells bear microvilli while others have cilia, layer may have goblet cells (mucus-secreting unicellular glands)
function: absorption, secretion of mucus, enzymes, and other substances, ciliated type propels mucus or reproductive cells by ciliary action
location: non-ciliated type lines most of digestive tract (stomach to rectum), gall bladder, and excretory ducts of some glands, ciliated variety lines small bronchi, uterine tubes, and some regions of uterus
pseudostratified ciliated columnar
single layer of cells of differing heights, some not reaching free surface, nuclei seen at different levels, may contain goblet cells and bear cilia
function: secrete substances, particularly mucus,propulsion of mucus by ciliary action
location: non-ciliated type in males’ sperm-carrying ducts and ducts of large glands, ciliated variety lines trachea, most of upper respiratory tract
stratified cuboidal
generally two layers of cubelike cells
function: protection
location: largest ducts of sweat glands, mammary glands,and salivary glands
stratified columnar
several cell layers; basal cells usually cuboidal; superficial cells elongated and columnar
function: protection; secretion
location: rare in the body; small amounts in male urethra in in large ducts of some glands
endothelium
epithelial tissue found lining hollow organs
functions of epithelial tissue include:
protection
absorption
filtration
excretion
secretion
sensory reception
areolar connective tissue
gel-like matrix with all three fiber types: cells, fibroblasts, macrophages, mast cells, and some white blood cells
function: wraps and cushions organs, its macrophages phagocytize bacteria; plays important role in inflammation; holds and conveys tissue fluid
location: widely distributed under epithelia of body, forms lamina propria of mucous membranes, packages organs, surrounds capillaries
reticular connective tissue
loose network of reticular fibers in a gel-like ground substance; reticular cells lie on the network
function: fibers form a soft internal skeleton (stroma) that supports other cell types including white blood cells, mast cells, and macrophages
location: lymphoid organs (lymph nodes, bone marrow, and spleen)
dense, regular connective tissue
primarily parallel collagen fibers, a few elastic fibers, major cell type is fibroblast
function: attaches muscles to bones or to muscles, attaches bones to bones, withstands great tensile stress when pulling force is applied in one direction
location: tendons, most ligaments, aponeuroses
adipose connective tissue
closely packed adipocytes or fat cells, have nucleus pushed to side by large fat droplet
function: provides reserve food fuel, insulates against heat loss, supports and protects organs
location: under skin in subcutaneous tissue, around kidneys and eyeballs, within abdomen, in breasts
dense, irregular connective tissue
primarily irregularly arranged collagen fibers, some elastic fibers, fibroblasts is the major cell type
function: withstands tension exerted in many directions, provides structural strength
location: fibrous capsules of organs and of joints, dermis of the skin, submucosa of digestive tract
elastic connective tissue
dense regular connective tissue containing a high proportion of elastic fibers
function: allows tissue to recoil after stretching, maintains pulsatile flow of blood through arteries, aids passive recoil of lungs following inspiration
location: walls of large arteries, within certain ligaments associated with the vertebral column, within walls of bronchial tubes
hyaline cartilage
amorphous but firm matrix, collagen fibers form an undetectable network, chondroblasts produce the matrix and when mature chondrocytes lie in lacunae
function: supports and reinforces, serves as resilient cushion, resists compressive stress
location: forms most of embryonic skeleton, covers ends of long bones in joint cavities, forms costal cartilages of ribs, cartilages of nose, trachea, and larynx
elastic cartilage
similar to hyaline cartilage, but more elastic fibers in matrix
function: maintains shape of structure while allowing great flexibility
location: supports the external ear (
fibrocartilage
matrix similar to but less firm than that in hyaline cartilage, thick collagen fibers predominate
function: tensile strength allows it to absorb compressive shock
location: intervertebral discs. pubic symphysis, discs of knee joint
osseous tissue
bone tissue that is hard, calcified connective tissue whose matrix contains organic materials and mineral salts
→ contains osteoblasts, osteoclasts, osteocytes, and highly vascularized
function of osseous tissue
protects and supports the body’s structure, stores calcium, provides attachment points for muscles, marrow inside blood cell formation (hematopoiesis)
blood
liquid connective tissue (UNIQUE)
→ has erythrocytes, leukocytes, and thrombocytes
matrix is watery substance called plasma
function: transports oxygen & nutrients throughout cardiovascular system
function: transport respiratory gases, nutrients, wastes, and other substances
location: contained within blood vessels
skeletal muscle
long, cylindrical multinucleate cells, obvious striations
function: voluntary movement, locomotion, manipulation of environment, facial expression, voluntary control
location: in skeletal muscles attached to bones or occasionally to skin
cardiac muscle
branching, striated, generally uninucleate cells that interdigitate at specialized junctions (intercalated discs)
function: as it contracts, it propels blood into circulation, involuntary control
location: walls of heart
smooth muscle
spindle-shaped (elongated) cells with central nuclei, no striations, cells arranged closely to form sheets
function: propels substances or objects (food stuffs, urine, a baby) along internal passageways, involuntary control
location: mostly in walls of hollow organs
nervous (neural) tissue
neurons are branching cells, contains neuron processes (axon) that extend from cell body with dendrites
function: neurons transmit electrical signals from sensory receptors and to effectors (muscles and glands), supporting cells support and protect neurons
location: brain, spinal cord, and nerves
