Chapter 4: Histology Flashcards
What is epithelial tissue? (6)
- Mostly composed of cells
- Covers body surfaces
- Distinct cell surfaces
- Cell and matrix connections
- Nonvascular
- Capable of regeneration
What is the matrix?
the noncellular substances surrounding the cell consisting of a ground substance and proteins
What are the functions of Epithelial Tissue? (5)
- protecting underlying structures
- acting as a barrier
- permitting the passage of substances
- secreting substances
- absorbing substances
What is a free/ apical surface?
cell surface that is not attached to other cells
What is a basal surface?
cell surface that is attached to the basement membrane
What is a basement membrane?
specialized type of extracellular material secreted by epithelial and connective tissue cells. (think of it like tape)
What does simple mean in terms of cells?
single layer of cells
What does stratified mean in terms of cells?
Multiple layers
What does pseudo stratified mean in terms of cells?
Looks as if there are multiple layers but in actuality there is only one layer as each cell directly hits the basement layer
What does squamous mean?
flat
What does cuboidal mean?
cube shaped
What does columnar mean?
Rectangular shaped
What are desmosomes?
Reinforces the binding between cells. often in places that are subjected to stress.
What are tight junctions?
hold cells together, and form permeability barrier
Types:
-zonula adherans: weak glue between cells
-zonula occludens: permeability barrier, found in stomach, bladder, so chemicals cannot pass through
What are gap junctions?
protein channels that aid in intercellular communication, coordinates functions of cardiac and smooth muscle
What are exocrine glands?
open contact maintained with exterior; ducts
What are endocrine glands?
No open contact with exterior, no ducts, produce hormones, release through blood
What are multicellular glands?
simple and compound ducts
- ducts end in tubules or sac-like structures: acini
- ducts end in simple sacs: alveoli
What is an example unicellular gland?
goblet cells
What is a merocrine gland?
cells of the gland produce secretions by active transport, use exocytosis
What is an apocrine gland?
portion of the cell is pinched off containing secretory products
What is a holocrine gland?
Entire cells are shed off containing secretions and are replaced by other cells deeper in the gland by mitosis
Blasts vs. Cytes vs. Clasts
Blast: build matrix
Cytes: maintain matrix
Clasts: break down matrix
What are mast cells?
contain inflammatory chemicals which release in sites of injury
What are mesenchymal cells?
connective tissue stem cells
What are collagen fibers?
strong, flexible microscopic ropes. found in tendons, ligaments, and bones
What are reticular fibers?
very fine collagen fibers, the branch out (like strings of the collagen rope)
What are elastic fibers?
Has a spring like appearance/function. stretches in respond to force and recoils when relaxed. not as strong as cartilage but, more flexible
What is hyaluronic acid?
has a glassy like appearance, good lubricant in joints, found in synovial fluid, vitreous eye fluid, and connective tissue, reduces friction
What is proteoglycan?
attaches to hyaluronic acid, to trap water like sponges
What are glycosaminoglycans?
polysaccharide components of proteoglycan
What is chondroitin sulfate?
a type of proteoglycan
What are adhesive molecules?
Hold proteoglycan aggregates together (-nectin)
What is a mesenchyme?
Source of all adult connective tissue
What is mucus connective tissue?
found only in the umbilical cord. wharton’s jelly
What is connective tissue proper?
Loose: areolar, reticular, adipose
Dense: dense regular collagenous, dense regular elastic, dense irregular collagenous, dense irregular elastic
What are the supporting connective tissues?
hyaline cartilage, fibrocartilage, elastic cartilage, bone
What is the fluid connective tissue?
Blood, bone marrow
What is areolar connective tissue?
has loose packing material called stroma,
attaches skin to underlying tissues,
contains collagen, reticular, elastic fibers,
cells include fibroblasts, mast, lymphocytes, adipose, macrophages
What is adipose tissue?
fat tissue
What is reticular tissue?
- forms structure of lymphatic and hemopoietic tissues
- fine reticular fibers
- spaces between cell contain white cells and dendrite cells
What is the difference between tendons and ligaments?
Tendons connect muscle to bones, ligaments connect bones to bones
What is perichondrium?
dense irregular connective tissue that surrounds cartilage, fibroblasts in this structure can differentiate into chondroblasts
What are chondrocytes?
cartilage cells
What are lacunae?
spaces in which chondrocytes are located, surrounded by matrix, without this cells would die.
What is hyaline cartilage?
large amount of collagen fibers, evenly distributed in proteoglycan matrix. found in areas for strong support and a little flexibility (ribs, trachea, bronchi, on ends of bones (epiphysis)
What is fibrocartilage?
thick collagen fibers distributed in the proteoglycan matrix, slightly compressible and very tough, found in pressure areas, as shock absorber (knee, jaw, vertebrae disks)
What is elastic cartilage?
elastic and collagen fibers embedded in proteoglycans, rigid but elastic. found in external ears, and epiglottis
What is trabeculae?
beam in bone anchoring strands of spongy bone
What is lamellae
layers of compact bone
What is skeletal muscle?
voluntary, striated, multi-nuclei
What is cardiac muscle?
involuntary, striated, branched, single nuclei
What is smooth muscle?
involuntary, no striations, single nucleus
What are intercalated disks?
Faint lines located between cells, containing gap junctions, found in cardiac tissue
Multipolar vs bipolar vs unipolar?
- several dendrites one axon
- one dendrite one axon
- axon and dendrite are one unit
What is synovial fluid?
rich in hyaluronic acid, reducing friction to allow movement. found in joints
What is a labile cell?
one that goes through cycling mitosis
What is a stable cell?
one that has no mitosis after growth ends, but can divide incase of injury (liver, pancreas, endocrine cells)
What is a permanent cell?
if killed will be replaced by a different type of cell, very limited regenerative ability (nervous, skeletal, and cardiac muscle)
What is a primary union?
edges of wound are close together, allows for easier healing
What is a secondary union?
edges of wound are not close, greater chance of scarring and infection
