Histology Flashcards
Tissues
Groups of cells similar in structure that perform common or related function
Four Basic Tissues
epithelial, connective, muscle, and nervous tissue
Epithelial
a sheet of cells that covers body surfaces or cavities
Two Types of Epithelial
- Covering and lining epithelial
- Glandular epithelia
Glandular Epithelia
Secretory tissue in glands
Functions of Epithelial Tissues
protection, absorption, filtration, excretion, secretion, and sensory reception
Connective Tissue
- mainly helped by extracellular matrix
- connects things and makes up cartilage
- widest range of properties
Epithelial Tissue Charactertistics
Polarity
Specialized contacts
Supported by connective tissues
Avascular, but innervated
Regeneration
Polarity
having a top and bottom
Avascular
without blood supply
Apical side
top ; exposed to cavity
Basal side
inwards to body ; connects to connective tissue
Basal Lamina
connective tissue that connects to bottom of epithelial tissue
Reticular Lamina
- under basal lamina
- consists of collagen fibers
Specialized contacts
- have tight junctions and desmosomes that allow formation of sheets of epithelial tissue
Lack of Desmosomes
causes blisters
Simple Epithelia
a single layer thick
Stratified Epithelia
two or more layers thick and involved in protection (example: skin)
Squamous
flattened and scale like
Cuboidal
box-like, cube
Columnar
tall, column-like
Naming in Stratified Epithelial Cells
In stratified epithelia, shape can vary in each layer, so cell is named according to the shape in apical layer
Simple Squamous
thinnest layer ; makes absorption and secretion fast
Simple Cuboidal
Roughly same size for length and
- Forms walls of smallest ducts of glands and many kidney tubules
Simple Columnar
Single layer of tall, closely packed cells ; involved in absorption and secretion and have cilia
- Found in digestive tract, gallbladder, ducts of some glands, bronchi, and uterine tubes
Pseudostratified columnar epithelium
- respiratory eptihelial
- Cells vary in height and appear to be multi-layered and stratified, but tissue is in fact single-layered simple epithelium
Stratified Squamous
- protective
- on top of skin and esophagus
- not good absorption and etc.
Transitional Epithelium
- forms lining of hollow urinary organs
- stretchy and stays waterproof
Gland
one or more cells that makes and secretes an aqueous fluid called a secretion
Endocrine
internally secreting ; drops stuff straight into circulatory system which negates ducts
Exocrine
externally secreting
Connective Tissue Function
-catch all group
- makes most of body
- binding and support, protecting, insulating, storing reserve fuel, and transporting substances (blood)
Extracellular Membrane
connect muscle to muscle, bone to bone, tissue to tissue
What does connective tissue make up?
Includes Bone, Blood, fat, and other tissues derived from the mesenchyme
Four Main Classes of Connective Tissue
Cartilage
Bone
Blood
Connective Tissue Proper
What makes connective tissue different from other tissues?
- all arise from mesenchyme tissue as their tissue of origin
-Have varying degrees of vascularity
-Cells are suspended/embedded in extracellular matrix
What is the function of the matrix?
Matrix supports cells so they can bear weight, withstand tension, endure abuse
Three Main Elements of of Connective Tissue
Ground substance
Fibers
Cells
What two substances make up the extracellular matrix?
The first two elements (ground substance and fibers)
Types of Fibers
- Collages
- Elastic
- Reticular
Collagen Fiber
Strongest and most abundant type
Tough; provides high tensile strength
Elastic Fiber
long, thin, elastin fibers that allow for stretch and recoil
Reticular Fiber
Short, fine, highly branched collagenous fibers (different chemistry and form from collagen fibers)
- offer more “give”
- holds water
Proper Dense Connective
- makes up tendons and ligments
Proper Dense Elastic Connective Tissue
- make up aorta and veins to allow for more flexibility \
Proper Dense Irregular Tissue
fibers do not run in same direction, hold together bones
Proper Loose Adipose
fat cells - store and release fat
Areolar Connective Tissue
- fat cells are contained
- Loose fibers allow for increased ground substance, which can act as water reservoir by holding more interstitial fluid
Cartilage and 2 features
- made by ground substance, chondrocytes (cartilage cells)
- avascular and cannot regenerate well
Hyaline Cartilage
found in bones
Proper Cartilage Elastic
stretchier
Fibrocartilage
- found in between your vertebrae
- contains collagen that makes it extra dense
Osseus Tissue
- Bone
- Supports and protects body structures
- type of connective tissue
Blood
- plasma
Ground substance
background material within which all other connective tissue elements are embedded. ; consist mainly of water
Function of Skeletal Muscle Tissue
- attached to and causes movement of bones
- can be consciously controlled
Three types of muscle tissues
- Skeletal muscle
- Cardiac muscle
- Smooth muscle
Myofilaments
made up of actin and myosin proteins that bring about contraction
Muscle Fiber Features
cells that hold multiple nuclei and are striated
Cardiac Muscle Fibers Features
- found only in walls of heart
- involuntary muscle
- cells have many branches that join branches if other cardiac cells
- stimulated by each other
- one nuclei but visible striations
Intercalated discs
special joints where cardiac cells are joined with gap junctions that allow them to talk to each other
Smooth Muscle Tissue Features
- found in walls of hollow organs
- no visible striations
-involuntary - found in glands
- one nucleus
Nervous Tissue
Main component of nervous system (brain, spinal cord, nerves)
Neurons
specialized nerve cells that generate and conduct nerve impulses
Glial (Neuroglial) cells
support, nourish, and protect the neurons
