Tissue and Skin Lab

levels of structural organization

cells, tissues, organs, organ systems

histology

study of tissues

tissue

a group of similar cells working together for a common function

organ

2 or more tissue types working together for a particular function

4 primary tissue types

epithelial, connective, muscle, nervous

epithelial tissue function

Forms boundaries between different environments, protects, secretes, absorbs, filters

nervous tissue function

Internal communication

muscle tissue function

Contracts to cause movement

connective tissue function

Supports, protects, binds other tissues together

nervous tissue locations

Brain, spinal cord, and nerves

muscle tissue locations

Muscles attached to bones (skeletal)

Muscle of heart (cardiac)

Muscle in walls of hollow organs (smooth)

epithelial tissue locations

Skin surface (epidermis)

Lining of GI tract organs and other hollow organs

connective tissue locations

Bones

Tendons

Fat and other soft padding tissue

2 types of epithelial tissue

Covering and Lining epithelia (focus on this more)

Glandular epithelia

simple epithelia

one layer - absorption and secretion

stratified epithelia

2 or more layers - protection from abrasion

squamous epithelia

flat cells

cuboidal epithelia

cubed cells (tall as they are wide)

columnar epithelia

tall cells

transitional epithelium (description)

stratified, multiple cell layers

basal layer - cuboidal or columnar

apical layer (dome shaped) - change shape depending on degree of stretch of the organ, when relaxed cells are rounded dome shaped and dead, when stretched cells flatten

transitional epithelium (function)

stretched to accommodate urine volume changes

transitional epithelium (location)

urinary systems, urthera, olnly found in urinary system

simple squamous epithelium (description)

single layer of flattened cells

simple squamous epithelium (function)

diffusion/filtration

allows materials to pass by, located at sites where protection is not important

simple squamous epithelium (location)

alveoli (air sacs) of lungs, blood vessels, lining of heart chambers, serosa

simple squamous epithelium

simple cuboidal epithelium (description)

single layer of cube shaped cells

simple cuboidal epithelium (function)

secretion and absorption

cells releasing substances for body functions, while taking substances from the body's outside into the bloodstream or cells

simple cuboidal epithelium (location)

kidney tubules, some glands

simple cuboidal epithelium

simple columnar epithelium (description)

single layer of tall cells, may have cilia on the apical surface (ciliated), also contains goblet cells

simple columnar epithelium (function)

secretion and absorption

cells releasing substances for body functions, while taking substances from the body's outside into the bloodstream or cells

simple columnar epithelium (location)

jejunum of small intestine, stomach, some glands (non-ciliated), uterine tubes and portion of uterus (ciliated)

simple columnar epithelium

goblet cells

mucous secreting glands, appear as white spheres within the epithelium

cilia

hair-like projections on apical surface of cells, move to propel substances

pseudostratified ciliated columnar epithelium (description)

single layer of tall cells that appears stratified since cells vary in height, but not all cells reach the apical surface, also can be ciliated or non-ciliated

pseudostratified ciliated columnar epithelium (function)

secretion of substances especially mucous, propulsion of mucus by ciliary action

pseudostratified ciliated columnar epithelium (location)

trachea, bronchi, lining respiratory passages (ciliated), male sperm carrying ducts (nonciliated)

pseudostratified ciliated columnar epithelium (bottom part is hyaline cartilage)

stratified squamous epithelium (description)

multilayers with apical surface cells flattened, basal cells are cuboidal or columnar, can be keratinized (when it is surface cells are dead and full of keratin, basal cells are mitotically active and produce new cells) or non keratinized

stratified squamous epithelium layers

statum corneum (superficial layer, dead flat cells with keratin) stratum basale (deep mitotic layer, single layer of cube like cells) basement membrane

stratified squamous epithelium (function)

protection from friction and abrasion, forming tough barriers on external and internal surfaces

stratified squamous epithelium (location)

epidermis of skin (scalp), esophagus, vaginal lining, oral cavity

stratified squamous epithelium

keratin (keratinized)

tough, structural protein

transitional epithelium

connective tissue (3 subclasses)

connective tissue proper, supporting connective tissue, fluid connective tissue

connective tissues (common features)

all derived from the embryonic tissue mesenchyme

all are mostly composed of extracellular matrix (ECM)

extracellular matrix

non-living (protein fibers + ground substance)

It is the composition of this that makes specific tissues so different from each other

areolar connective tissue (description)

Loose connective tissue with a gel-like matrix containing all three fiber types (collagen, elastic, reticular)

fibroblasts

fiber producing cells (main type of cell in areolar connective tissue and dense irregular connective tissue)

areolar connective tissue (collagen fibers)

long cable like, strong and flexible, appear thick and pink

areolar connective tissue (elastic fibers)

thin fibers, stretch and recoil, appear as dark thin lines

ground substance

gel like white areas on slide (areolar connective tissue and dense irregular connective tissue)

areolar connective tissue (function)

Cushions organs, holds tissue fluids, binds different tissues together while allowing flexibility

areolar connective tissue (location)

Under the skin (subcutaneous layer); surrounding blood vessels, nerves, and organs

areolar connective tissue (dark spots fibroblasts nuclei, thin dark lines elastic fibers, lighter thick lines collagen fibers, white space ground substance)

adipose tissue (description)

loose connective tissue made mostly of fat-storing cells

adipose tissue (adipocytes)

main type of cell in this tissue, appears as large empty-looking cells due to lipid storage, the middle is the fat storage area

adipose tissue (signet ring nucleus)

the nucleus of adipocytes, pushed to the side of the cell

adipose tissue (function)

Stores energy, insulates the body, and cushions/protects organs.

adipose tissue (location)

Beneath the skin (hypodermis), around kidneys, behind the eyeballs, in breasts

adipose tissue

dense irregular connective tissue (description)

Densely packed collagen fibers running in many directions; few cells (mainly fibroblasts)

dense irregular connective tissue (collagen fibers)

dominant fiber type, irregularly arranged bundles, pink colors

dense irregular connective tissue (function)

Provides strength and resists tension from multiple directions

dense irregular connective tissue (location)

Dermis of skin, fibrous capsules of joints and organs (e.g., kidney capsule)

dense irregular connective tissue

hyaline cartilage (description)

Firm yet flexible connective tissue

hyaline cartilage (chondrocytes)

cartilage cells, major cell type of this tissue

hyaline cartilage (lacuna)

open spaces in tissue containing chondrocytes

hyaline cartilage (ECM)

frosted glass appearance, fibers not visible

hyaline cartilage (function)

Provides support and reduces friction between bony surfaces; resists compressive forces.

hyaline cartilage (location)

Nose, trachea, larynx, ends of long bones, costal cartilage (connecting ribs to sternum).

hyaline cartilage, dark spots are chondrocytes, lacuna is the open space where the cell sits, and matrix is around it

bone (compact bone) (description)

Hard, calcified matrix with osteocytes in lacunae; highly vascular (packed with an extensive network of blood vessels that keep the tissue alive)

bone (compact bone) (osteocytes)

bone cells, major type of cell in this tissue

bone (lacuna) (description)

open spaces in matrix that houses the osteocytes

bone (compact bone) (osteon/haversian system)

circular structural units of compact bone, comprised of multiple concentric layers of calcified matrix (lamellae) surrounding a central canal

bone (compact bone) (central/haversian canal)

opening in the center of each osteon, space for the passage of blood vessels and nerves

bone (compact bone) (lamellae)

rings/layers of calcified matrix around the central canal

bone (compact bone) (canaliculi)

small canals through matrix, appear as cracks, connect lacuna and osteocytes together

bone (compact bone) (function)

Supports body, protects organs, stores minerals, produces blood cells

bone (compact bone)

blood (description)

Fluid connective tissue with plasma matrix; contains Erythrocytes (red blood cells), Leukocytes (white blood cells), and Thrombocytes (platelets)

blood (plasma)

fluid ECM, white areas of slide

blood (erythrocytes)

red blood cells, look like little pink dots without nuclei

blood (leukocytes)

white blood cells, look like larger cells with dark staining nuclei

blood (thrombocytes)

platelets, looks like really tiny specks/dots

blood (function)

Transports oxygen, nutrients, hormones, wastes; immune defense, clotting.

blood, erythrocytes=pink, leukocytes=purple, thrombocytes=tiny

loose connective tissue proper types

areolar connective tissue, adipose tissue

dense connective tissue proper types

dense irregular connective tissue

supporting connective tissue

hyaline cartilage, bone (compact) tissue

fluid connective tissue

blood

muscle tissue types

skelatal, cardiac, smooth

skeletal muscle (description)

Long, cylindrical, multinucleated cells with striations; under voluntary control.

skeletal muscle (function)

Voluntary movement, posture, heat generation

skeletal muscle (location)

Muscles attached to bones