Histology Quiz

Histology

theory of tissues

Tissues

• group of cells that perform a similar or related function

• They improve the efficiency of operations because they enable tasks to be shared amongst various specialized cells

Four tissue groups

epithelial, connective, muscle, and nervous

epithelial tissue

• Organized into single or layered sheets of cells

• lines internal and external surfaces

• protects underlying structures from wear, infection, and pressure

• packed close together with little or no intercellular material between them

• may be ciliated for absorption, secretion, or filtration

Simple (epi)

singled layered

stratified (epi)

two or more layers

squamous (epi)

flat

cuboidal (epi)

roughly cube-shaped

columnar (epi)

column shaped

transitional (epi)

varying shapes that stretch

Simple squamous epithelium

• Structure= single layer of flat cells

• Function = transport and absorption, diffusion, filtration

• Location= lining of blood & lymphatic vessels

Stratified squamous epithelium

• structure=several layers of closely packed cells, outer layer is flattened cells

• function= protection against microtubles

• location= surfaces of lining of mouth, esophagus, surface of skin

Simple columnar epithelium

• structure= arranged in single layer

• function= secretion and absorption of nutrients

• location= line stomach and intestines, respiratory, and reproductive tracts

simple cuboidal

• structure= cube shaped cells in a single layer

• function= secretion and absorption

• location= glands and kidney tubules

pseudostratified epithelium

• structure= single layer of tall cells that appear layered because of different heights

• function= protection against dust or foreign particles into the lungs

• location= surface of lining of trachea

stratified transitional epithelium

• structure= many layers of tall cells that have cells of various shapes, capsule of stretching

• function= protection

• location= urinary bladder

muscle tissue

highly specialized cells called fibers

features of muscle tissue

• contractile

• responsible for both voluntary and involuntary movements

Cardiac muscle (muscle tissue)

• Structure: 

  • striated involuntary

  • cylindrical, branching cells interconnected  

  • One centralized nucleus 

• Location: Wall of the heart 

skeletal muscle

• Structure: 

  • striated voluntary

  • large, long, cells

  • multiple peripheral nuclei.

• Location: muscles attached to bones

smooth muscle

• Structure: 

  • non-striated involuntary

  • spindle-shaped cells 

  • single central nucleus.

• Location: lining of GI tract, ducts of glands, walls of blood vessels, eye muscles

Connective tissue

• major supporting tissue of the body

• most varied

• location= found in skin, membrane, muscle, bones

• function= binds other structures together, provide support, and protection against damages, infection, or heat loss

6 types of CT

• areolar connective tissue

• adipose(fat)

• fibrous

• bone

• cartilage

• blood and hematopoietic tissue

proper/ordinary CT

• loose CT

  • areolar and adipose

• dense CT

  • fibrous CT

specialized CT

• supportive CT

  • cartilage and bone

• fluid

  • blood and hematopoietic

Areolar CT

• most widely distributed CT

• “glue” that gives form to internal organs

• delicate web of fibers

  • variety of cells in loose matrix

adipose (fat CT)

• store lipids

• contains large fat compartments in cells

fibrous CT

• Bundles of strong white collagen fibers arranged in parallel rows; dense

• Composes tendons & ligaments  

• Provides strength & flexibility, does not stretch

• Anchors muscles to bones 

Bone (CT)

• most highly specialized forms of CT

• matrix is hard and calcified

• forms building blocks called osteons

• stores calcium and provides support and protection

cartilage (CT)

• matrix is consistency of firm plastic

  • flexible with embedded chondrocytes

• found in nasal septum and ear

blood (CT)

• matrix is liquid

• transportional and protective functions

• red and white blood cells

• found in blood vessels

hematopoietic tissue

• blood-like CT in red marrow cavities of bones and organs such as lymph nodes

• fomation of blood cells and lymphatic cells to defend against disease

Neruons (nervous tissue)

• structural and functional cells of NS

• specialized to transmit and receive nerve impulses

neuroglia (NT)

• supporting and connecting cells of the NS

• highly branched supportive cells, which do not conduct nerve impulses

Tissue Repair

• epithelial and CT= regenerate

• muscle and neruons= limited abilities

• neurons in the brain and spinal cord= do not grow back

Skin

the body’s largest organ

thermoregulation

cooling by sweating, heating by flattening the fair

sensory reception

the skin senses touch, heat, vibration, pressure, and pain for information about changes in the environment

vitamin manufacture

the skin absorbs UVB lights to synthesize

Epidermis

outermost layer of skin, consists of stratified squamous epithelium with up to 5 layers of skin

dermis

deeper layer of skin, made up of primarily connective tissues, fiber and collagen

structure of skin

cells flatten and become keratinized as they migrate from the basal layer to the surface

stratum corneum (epidermis)

dead skin cells flake off and replaced with skin below

stratum lucidum(epidermis)

in thick skin, now in all skin, in palms, soles of feet, an additional layer

stratum granulosum(epidermis)

granular, cells getting compressed and dying

stratum spinosum(epidermis)

spiky appearance with dyes

stratum basale(epidermid)

holds epidermis onto dermis below it, mitosis living layer

dermal papillae(dermis)

projections that are important to keep the dermis and dermis together. They form ridges and grooves that make fingerprints unique

deeper areas of dermis filled with

collage fibers(strength), elastic fibers(flexibility and ability to stretch), reticular fibers(support), nerves and nerve endings, muscle fibers(arrector pili),

3 types of finger prints

arches, whorls, and loops

arches

the ridges extend from one side of the finger to the other, rising in the center

whorls

the ridges are in a circular pattern

loops

one or more ridges enter from one side of your impression, curves, and leaves from the same side.

hair

grows from a called the hair follicle, hair growths begins from hair papilla(base of follice)

arrector pili muscle(hair)

specialized smooth muscle that moves hair and causes hair to stand up straight, goosebumps

receptors

specialized nerve endings allow for sensations of touch, pain, temperature, and pressure

meissner’s corpuscle(receptors)

superficial nerves, capable of detecting light touch

pacinian corpuscle(receptors)

deep nerves, capabel of detecting pressure

nails

made of keratin, hidden part is the root and is hidden by the cuticle

eccrine(sweat glands)

small, numerous, and widespread throughout the body, produce sweat and body temperature

apocrine sweat glands

larger than eccrine, found primarily in axillary and pelvic regions, begin to function at puberty, secrete a thick secretion

sebaceous glands

secrete oil to lubricate hair and skin, sebum accumulation in follicles= acne and blackheads

squamous cell carcinoma(skin cancer)

malignant tumor of the epidermis

basal cell carcinoma(skin cancer)

less likely to metastasize; usually on upper face, begins in cells at base epidermis(basal layer)

melanoma(skin cancer)

malignant, most serious form of skin cancer, develops from pigmented moles and transforms into dark, spreading lesions.