Histology exam 1

Fixatives

Acts to stabalizeand preserve specimen features.

• Additive: Formaldehyde, gluteraldehyde, OsO4

• Coagulative: EtOH, acetone

Dehydration and clearing

Removes H20 to allow penetration of embedding media

• EtOH or acetone through Xylene

Embedding

embedding media support sample during microtomy

parafin

relatively soft wax good down to -5 micrometers

plastic

various types and hardness, good to 0.01 micrometers

microtomy

Slices specimen blocks into thin sections

Haemotoxylin

a base that binds acids

• stains the nuclei blue to brown depending on the method

• referred to ad a basic stain

acids

basic substances will bind to

• the cytoplasm stains red to pink

• referred to as an acid stain

Magnification

how much an image is enlarged under a microscope,

resolution

The amount if detail you can see.

empty magnification

if you can magnify an image without increasing its resolution

two dimensional microscopy

LM, TEM

there dimensional microscopy

stereo, confocal, phase, DIC, SEM

Epithelial tissue

Tissue that generally forms the functional part of an organ.

parenchyma

composed of the cells responsible for the organs specialized functions

stroma

the cells that play a supporting role in an organ.

connective tissue

What tissue does the storm consist of in the brain/ spinal cord?

avascular layer

Nutrients supplies by diffusion from nearby capillaries

lines the cavities of organs and cover the body surfaces.

Where is epithelial tissue found?

Epithelia

Covers, lines, and protects surfaces. Absorption, and secretion.

epidermis (skin)

Epithelia that covers, lines, and protects surfaces.

intestinal lining

Epithelia that absorbs

parenchyma cells of glands

Epithelia that Secretes

Basement membrane

Non celular layer of proteins, carbohydrates, and glycoproteins for cell adhesion and signal change.

• collagen IV, laminin, nidogen, fibronectin, perlecan, hyaluronan.

lamina propria (epithelium)

the connective tissue that underlies the epithelial tissue lining the organs the digestive tract, urinary, and respiratory organ systems.

simple

one layer

more than one layer

stratified

Simple Squamous (epithelium)

Covering and protection

• Absorption, diffusion

• endothelium, mesothelium, visceral normans capsule (kidney), pleural lining (the lungs).

Simple Cuboidal (Epithelium)

Absorption, secretion

• Kidney tubules

• Salivary glands

• mammary glands

Simple columnar (epithelium)

Absorption, secretion

• intestinal epithelium

in the skin where is helps prevent severe dehydration

stratified squamous keratinized epithelium is found where?

Pseudo-stratified (ciliated columnar)

Found in the trachea

Desmosomes, hap junctions, z. adherans

stratified epithelia contains prominent characteristics including

mouth, esophagus, vagina

stratified squamous tissue is found where

Stratified Squamous

high proliferative rate (allows for high turnover rate). Keratinized and non-keratinized.

Stratified cuboidal

    Lining the excretory/ secretory ducts. Absorptive/ secretory function is limited. (milk ducts)

stratified Columnar

Protection and secretory function. (conjunctiva: mucous, tear fluid, bactericides)

transitional epithelium

    Urethra and bladder. Adapted to respond to distension/ stretch. Binucleate lumenal cells are relatively common. Extreme distensibility.

Glandular epithelia

Exocrine glands: secretion via ducts or lumen discharge

• Salivary, sweat, mucous, liver, pancreas

• Endocrine glands: Ductless secretion

Merocrine

secretion by exocytosis (no membrane loss)

Apocrine

Apical portions of cell get secreted

Holocrine

Whole cell (or lysed cell) is secreted

simple

one layer

stratified

more than 1 layer

Metaplasia

• Epithelial tissue are capable of adaptive morphological responses to external stimuli

• reversible

muscle tissue

specialized cells with contractile properties

• highly cellular tissue with prominent cytoplasmic features.

• Skeletal, smooth, cardiac

skeletal

• strong, quick discontinuous, voluntary, contraction

cardiac

• strong, quick, continuous, involuntary, contraction

smooth

weak, slow, involuntary, contraction

skeletal muscle features

• multinucleate syncitia

• peripheral nuclei

• visible striations due to sarcomere architecture

• non- mitotic

• satellite cells

cardiac muscle features

• primarily mononuclear

• centrally located nuclei

• striated

• branched fibers

• intercalated discs

smooth muscle features

• fusiform shape

• no visible striations

• mononuclear

connective tissue

provide structural and metabolic support for other tissue types

• derived from the mesoderm (mesenchyme)

• characterized by and classified by intercellular matrix

• 
  

Fibroblasts (C.T)

metabolic support and production of the fibers and matrix

mesenchymal cells (C.T)

undifferentiated precursor cells (stem cells)

immunosurveillance cells (C.T)

Macrophages, mast cells, lymphocytes, plasma cells, etc.

specialized cell types (C.T)

Chondrocyte, adipocyte

Keloid (C.T)

excessive collagen deposition at sites of scarring

Elastin Fibers (C.T)

Elastin

• less rigid than collagen

• Automatic recoil, provides resiliency

• Usually stained purple, thinner than collagen

reticular fibers

• fine meshwork of short branched collagen fibers

• Rich in sugars

• Agrophylic

• Supports framework in solid organs (ex. lymph nodes, liver, etc.)

glycosaminoglycans

non- sulfated: hyaluronate skin, cartilage

Basement membrane

Specialized layers of ECM surrounding or adjacent to all epithelia, endothelia, peripheral nerves, muscle cells, and fat cells

functions of basement membrane

Anchorage of epithelial tissues; reservoir of growth factors; final transduction

Dense C.T

• Coarse collagen fibers and fibroblasts predominate

• frequently found under epithelial layers

• skin, organ capsules, periosteum

Dense irregular C.T

seemingly random arrangement and distribution of components

• plywood, found in dermis

Dense regular C.T

orderly arrangement od components

• tendons and ligaments

Loose C.T (areolar C.T)

open mesh of fibers and cells

Mesentery, surrounding blood vessels

cells found in connective tissue

Fibroblasts, adipocytes, macrophages, white blood cells

cells found in epithelial cells

cuboidal, columnar, squamous

cells

muscle fibers (myocytes)

Mucous C.T

The umbilical cord

• looks like a face

Mucous C.T

Fibroblasts, mesenchymal cells, collagen fibers, Matrix

function og mucous C.T

support with extreme flexibility

found in mesenchymal C.T

mesenchymal cells, collagen fibers, cell processes

reticular C.T

fine mesh to support other cell types (liver, lymph nodes)

adipose (specialized C.T)

support, insulation, protection, energy storage (lipids)

cartilage (specialized C.T)

support, protect, and allow flexibility.

• hyaline, fibro, elastic

hyaline

articulations

elastic

ear, epiglottis

fibro

intervertebral discs, clavicle, pubic symphysis

features of cartilage

avascular, chondrocytes embedded in the lacunae, perichondrium

cells on the osseous tissue (C.T)

osteoblasts, osteocytes, osteoclasts

• osteoid fibers

building bones

function of osteoblasts

degrading bone

function of osteoclasts

Nervous tissue

function: integration, regulation, coordination

central nervous system

brain and spinal cord

peripheral nervous system

nerves and ganglia

mylenation

provides insulation, thus increases velocity of impulse transmission.

• Schwann cells (PNS)

• oligodendrocytes (CNS)

endocardium

endothelial cell lining the heart chambers

cardiac muscle features

Spontaneous contractions

• intercalated discs

SA node

located in the right atrium near the vena cava

Small cardiac muscle cells w/ scanty myofibrils

AV node

located at the base of right atrium

• Receives stimulus from internodal tracts

• connects to bundle of his

• Purkinje fibers

Purkinje fibers

specifically modified cardiac muscle cells

arteries and veins

blood transport

conductance vessels

transport (arteries and arterioles)

exchange vessels

metabolite and hormone exchange

capillaries

capacitance vessels

reserve volume

• veins and venules

structure of arteries and veins

tunica intima, tunica media, and tunica externa