Histology

What is histology?

study of tissues

There are _______ different cell types

200

cells of similar function become _______

Tissues

An organ is composed of of ____ or more tissue types

2

removal of tissues for diagnostic purposes

biopsy

examination of organs of a dead body to determine cause of death

autopsy

What are the 4 primary tissues?

epithelial, connective, muscular, nervous

Describe epithelial tissue

Flat sheet with upper surface exposed to the environment or an internal body cavity

No blood vessels

Which tissue type consists of layers of closely adhering cells

Epithelial

Why are there no blood vessels in the epithelial tissues?

The blood vessel would not allow enough surface area for our skin to absorb nutrients

What is the basement membrane?

layer that anchors epithelial tissue to underlying tissues

Name 3 functions of epithelia tissue

Protection

Barrier

Permits passage of substances

simple vs stratified epithelial tissue

Simple has one layer of cells while stratified has more than one layer. Simple is found in body structures where absorption, decoration and filtration occurs while stratified serves as protection.

Does simple or stratified tissue allow for diffusion of gases, filtration of blood, secretion, absorption

Simple

Does simple or stratified tissue allow for protection, particularly against abrasion

Stratified

______ tissue acts a filter and allow for diffusion

Squamous

_______ and _______ may include goblet cells that produce and secrete mucus?

Cuboidal and columnar

Name the 3 types of simple epithelium

1. Simple squamous

2.simple cuboidal

3. Simple columnar

Which type of simple epithelium lines the GI tract, uterus, kidney, and uterine tubes

Simple columnar

Which type of simple epithelium is in alveoli

Simple squamous

A single row of cells, some not reaching free surface

pseudostratified epithelium

More than one layer of cells

stratified epithelium

________ are the deepest cells on the basement membrane

Stratified epithelia

________ epithelium has surface layer of dead cells

Keratinized

example of keratinized stratified squamous

Nails, skin

________ epithelium lacks the layer of dead cells

nonkeratinized

examples of nonkeratinized stratified squamous

tongue, oral mucosa, esophagus, and vagina

Where is transitional epithelium found in the body?

urinary bladder, ureters

What would happen if we didn't have transitional epithelium?

Bladder would not be able to stretch, filtration would back up into blood because ureter cannot expand

what accommodates fluctuations in the volume of fluid in an organ or tube; protection against the caustic effects of urine.

Transitional Epithelium

Which tissue is widely spaced cells separated by fibers and ground substance

Connective

Most abundant and variable tissue type

connective tissue

Connective tissue locations

under skin, surrounding organs, blood, bones

Fibers of connective tissue

collagen, elastic, reticular

Type of fiber in collective tissue that is tough and stretch resistant

Collagen

Type of fiber in collective tissue that is thin and has collagen fibers coated with glycoprotein

Reticular

Type of fiber in collective tissue that stretches and recoils like a rubber band

Elastic

Why would be reticular fibers be found in the spleen

Important for blood filtration

Which connective tissue has abundant collagen fibers that resist stretching and are parallel to each other

Dense regular

______ is important for tendons and ligaments

Dense regular connective tissue

Connects muscles to bones

tendons

connects bones to other bones

ligaments

Empty-looking cells with thin margins; nucleus pressed against cell membrane

adipose tissue

adipose tissue function

protects, insulates, stores fat

______ is supportive connective tissue with a rubbery matrix

Cartilage

Does cartilage have blood vessels? Is this good or bad?

No, can be bad because it will take longer for abrasion to heal

What does skeletal muscle do?

voluntary movement

What does cardiac muscle do?

pumps blood, involuntary

What do skeletal and cardiac muscle cells share in common?

striations

Does smooth muscle have striations?

no striations, meant for slower continuous contractions

Where is smooth muscle found?

walls of hallow internal organs (stomach, blood vessels, uterus)

Long, cylindrical, unbranched cells with striations and multiple nuclei

skeletal muscle

Short branched cells with striations and intercalated discs

One central nuclei per cell

cardiac muscle

Hard connective tissue composed of living cells (osteocytes) and mineralized matrix

bone

gives strength and rigidity; allows bone to support/protect other tissues, organs

matrix

2 types of bone

compact and spongy

The matrix contains

Plasma

The _____ contains the nucleus

cell body

Our _____ cells have the ability to produce action potentials

Nerve

Which muscles produce action potentials

Skeletal and cardiac

Support cells of the brain, spinal cord and nerves

neuroglia

Prevents passage between cells

Tight junctions

Tight junctions are especially important in ______ lining

Stomach

Allows excitation to pass from cell to cell to produce near-unison contraction

Gap junctions

Why are gap junctions important?

ensure a uni directional spread of action potential

_______ glands connect to surface with a duct (epithelial tube)

Exocrine

_______ glands secrete (hormones) directly into bloodstream

endocrine

tissue growth through cell multiplication

hyperplasia

enlargement of preexisting cells

hypertrophy

growth of a tumor (benign or malignant) through growth of abnormal tissue

neoplasia

Unspecialized tissues of embryo become specialized mature types

differentiation

Changing from one type of mature tissue to another

metaplasia

Hypertrophy of the heart

Increase in the SIZE of cells resulting in enlarged tissue mass. this increase may be caused by additional work by the tissue

Undifferentiated cells with developmental plasticity

stem cells

loss of cell size or number

atrophy

pathological death of tissue

necrosis

programmed cell death

apoptosis