Intro to human histology

GT BIOS3753

Tissue

group of cells within similar structure and function

Human Tissue Types

epithelial, connective, muscle, and nervous tissue

histology

study of tissues

periosteom

around bone and sensitive to pain

fertilized egg

zygote

zygote divides into

blastocyst

ectoderm

outer skin, epidermis and nervous system

mesoderm

skeletal, muscular, and circulatory system

endoderm

inner skin linings of the digestive and respiratory tracts

epithelial - definition

sheet of cells that covers body surfaces and lines inside of body cavities (covering and lining of tissues)

Epithelial - functions

protection, absorption, filtration, excretion, secretion, sensory reception, gas exchange

Avascularity

epithelial tissue does not have a blood supply

regeneration

replace lost tissue via cell division

Goblet cell

makes mucus

naming epithelial

number of cell layers followed by shape of cells

number of cell layers

simple: single layer, stratified: multiple layers, pseudostratified: artificial/false layers

single layer

simple/absorption and filtration (diffusion)

multiple layers

stratified/protection

pseudostratified

artificial/false layers - only one layer but gives appearance of many

shape of cells

squamous, cuboidal, columnar, transitional

squamous

flat and scale like

cuboidal

cube shaped

columnar

column shape

transitional

varies

simple squamous epithelium - description

single layer of flat cells with disc-shaped central nuclei and sparse cytoplasm

simple squamous epithelium - function

allows passage of materials by diffusion and filtration in sites where protection is not important. also secretes lubricant

simple squamous epithelium - location

air sacs of lung (alveoli), capillaries, linings of heart

Simple Cuboidal Epithelium - description

single layer of cube-like cells with large spherical centrally located nuclei

Simple Cuboidal Epithelium - function

secretion and absorption

Simple Cuboidal Epithelium - locations

kidney tubules, ducts and secretory portions of glands

lumen

inner portion of a tube

simple columnar epithelial description

single layer of tall cells with round/oval nuclei; some cells bear cilia; may contain goblet cells that produce mucus

simple columnar epithelium function

absorption; secretion of mucus and enzymes; cilia propel substances

simple columnar epithelium location

non-ciliated type lines digestive tract. ciliated type lines uterine tubes and uterus

pseudostratified columnar epithelium description

single layer of cells of differing heights so that nuclei are a differing levels; may contain goblet cells and bear cilia. All cells contact the basement membrane but not the free surface (only the tallest cells). Nuclei are at different levels giving the false appearence

pseudostratified columnar epithelium function

secretion, propulsion by ciliary action

pseudostratified columnar epithelium location

non ciliated type lines male reproductive ducts; ciliated type lines much of respiratory tract (i.e. trachea)

Stratified squamous epithelium description

thick layers of flattened cells; often keratinized layer and a mitotic layer

stratified squamous epithelium function

protects underlying tissues in areas subject to abrasion

stratified squamous epithelium location

non-keratinized type lines the mouth and vagina; keratinized type forms epidermis of skin

transitional epithelium description

resembles both stratified squamous and stratified cuboidal. Basal cells are cuboidal or columnar; surface cells are dome shaped

transitional epithelium function

stretches readily and permits distension

transitional epithelium location

lines uterus and urinary bladder

glandular epithelium endocrine glands

“ductless” glands that produce hormones

glandular epithelium exocrine glands:

glands possessing ducts

glandular epithelium merocrine (includes location)

secrete products by exocytosis. pancreas and sweat glands

glandular epithelium holocrine:

accumulate products until the cell ruptures. Sebaceous “oil” glands

connective tissue is the

most abundant tissue in the human body

ligament

bone to bone

you strain

muscles and tendons

sprain

injury to ligament

scar tissue

collagen stacked improperly

connective tissue types

ligaments, bone, adipose, blood

connective tissue function

binding and support (ligament), protection (bone), insulation (adipose), transportation (blood), absorb shock, immunity

ground substance

Unstructured material that fills the space between cells and contains the fibers

embryonic connective tissue overview

mesenchyme (all connective tissue derived), mucous connective tissue (Wharton’s jelly found in fetus)

mature connective tissue

loose connective tissue, dense connective tissue, cartilage, bone (osseous), blood (vascular)

mesenchyme

all connective tissues are derived from this

loose connective tissue types

areolar, adipose, reticular connective

dense connective tissue types

dense regular connective tissue, dense irregular connective tissue, elastic connective tissue

cartilage types

hyaline cartilage, firbocartilage, elastic cartilage

Blast =

baby

cyte

mature

blast cells are _____ cells that …

active cells that secrete both fibers and ground substances (matrix)

Cyte cells are _____ cells that…

mature cells that maintain (repair or regenerate) matrix.

connective tissue proper (blast and cyte)

fibroblasts/fibrocytes

cartilage (blast and cyte)

chondroblast/chondrocyte

blood (blast and cyte)

hemocytoblast/hemocyte

hematopoietic stem cells (produce what?)

blood producing cells

bone (blast and cyte)

osteoblast/osteocyte

loose connective tissue (definition)

loosely woven fibers

areolar (description)

most widely distributed connective tissues in the bodya

reolar (function)

binds body parts, wraps around small blood vessels and nerves, binds skin to underlying structures, composed mainly of fibroblasts

Adipose is primarily made of

adiposcytes

adipose function

storage of triglycerides, nucleus is pushed to the side, insulator, reduces heat loss through skin, energy reserve

adipose (location)

subcutaneous, around kidneys, omentum (over intestines), behind eyeball (orbital fat)

reticular composed of

reticular fibers

reticular (function)

forms stoma (internal framework) in organs; mainly lymphoid, supports white blood cells, binds smooth muscle cells together

reticular (location) - must know

spleen, lymph nodes, bone marrow

spleen ratio

1:3:5:7:9:11
1 inch thick, 3 inches wide, 5 inches long, 7 ounces, Lies deep between the 9th and 11th ribs in the left upper abdomen

dense regular connective tissue

fibrous connective tissue, bundles of collagen fibers with fibroblasts, strongest and most abundant, high tensile strength fibrous protein, collagen molecules are secreted, extracellular spaces and fibers are spontaneously formed called white fibers

white fibers

extracellular spaces and fibers are spontaneously formed

tendons

muscle to bone, rope or flat sheet

aponeuroses

sheet like tendons (muscle to other muscle/bones

ligaments

bone to bone. contain more elastin fibers so they have a better ability to stretch

dense irregular connective tissue contains

collagen fibers that have an irregular pattern

dense irregular connective tissue seen in

sheets. dermis of skin (under epidermis), periosteum of bone, heart valves

dense irregular connective tissue tensions are

exerted in various directions

cartilage: ability

to endure great stress

cartilage contains

dense network of collagen and elastic fibers embedded in chondroitin sulfate

chondrocytes are located

in spaces called lacunaec

cartillage has no

blood supply and no nerves

hyaline cartilage is the

most abundant type of cartilage

hyaline cartilage (location)

ends of long bones (articular cartilage), nose, trachea, bronchi, ends of ribshy

hyaline cartilage features/functions

flexibility, movement of joints, support

fibrocartilage (description)

chondrocytes scattered among collagen

fibrocartilage found in

pubic symphysis, intervertebral discs, menisci of the kneef

fibrocartilage functions

support and fusion, absorb compressive shock

elastic cartilage

similar to hyaline cartilage, more elastic fibers present (stretching)e

elastic cartilage location

pinna of ear, epiglottis, vocal cords, walls of artery