Tissues BIOL 3310 Anatomy and Physiology Lecture Exam 1

Epithelial tissues

cover external and internal surfaces of the body, always at least one exposed side, always one side connected to connective tissue

Connective tissue

protects and supports, most abundant and widely distributed tissue in body

Muscle tissue

create force to move, retains heat

nervous tissue

collect and analyze information about body, sends signals

What are the major functions of epithelial tissue?

selective barrier regulates movement

secretory surface releases products onto free surface

protective surface from environment

Apical surface

‘free’ or exposed surface of epithelial tissue

Lateral surface

surface where epithelial cells touch eachother

Basal surface/Basement membrane

surface where epithelial tissue touches connective tissue

What are the names of different numbers of cellular layers in epithelial tissue?

simple - 1 layer

stratified - 2+ layers

pseudostratified - one layer, appears to be more

What are the different shapes of epithelial cells?

squamous - amorphous

cuboidal - squared or circular

columnar - vertical rectangles, typically, nucleus in bottom half

Simple squamous epithelium

single row of thin amorphous cells, permits rapid diffusion/transport, found in kidneys

Simple cuboidal epithelium

single layer of square or round cells, permits diffusion/transport, always forms glands

Simple columnar epithelium

single layer of tall, rectangular cells, oval nuclei in base, permits diffusion/transport, found in gallbladder

may have cilia or goblet cells

Goblet cells

modified epithelial cells that secrete mucus

Cilia

hairlike microtubules, moves surface products

Pseudostratified columnar epithelium

seems multilayered, not all cells reach apical surface, all touch basement membrane, secretes and propels mucus, found in urethra

contain cilia and goblet cells

Stratified epithelium

2+ layers of cells, only deepest layer attached to basement membrane

What is the most common form of stratified epithelium?

Stratified squamous epithelium

What is transitional epithelium?

lowest layer starts as cuboidal, transforms to squamous. found in urethra

Keratinized

found on skin surface, resistant, has layer of dead cells

Non-keratinized

lacks surface layer of dead cells

Thick skin

made up of 5 layers, found on palms and soles, no extraneous structures

Thin skin

made up of 4 layers, found everywhere else, contains all extra structures of the skin

Layers of epidermis

Stratum -

basale

spinosum

granulosum

lucidum

corneum

Stratum Basale

deepest layer of columnar cells, most are keratinocytes, single layer

Stratum Spinosum

Where keratin is made

Stratum Granulosum

where keratin is bundled together and lipid is secreted that helps create a waterproof barrier

Stratum Lucidum

only seen in thick skin, appears white because of clear eledin protein

Stratum Corneum

most superficial layer of dead keratinocytes that are squamous in shape

Glandular epithelium

glands secrete a variety of chemicals and are usually not directly on surfaces

Endocrine glands

secretes hormones that diffuse into the blood after passing through interstitial fluid

Exocrine glands

secretes products such as sweat, oil, earwax, saliva, milk

Extracellular matrix

separates connective tissue cells from direct interaction, very vascular, supplied with nerves

except cartilage and tendons, which both lack blood supply and nerves

Fibroblasts

secrete fibers and components of ground substance, can only be made within cell then secreted

Macrophages

engulf bacteria and cell debris via phagocytosis

Mast cells

produce histamine, dilate to increase blood flow, causes inflammation to urge body to heal itself

Adipocytes

fat cells, store triglycerides

White blood cells

immune response, neutrophil and eosinophils

Plasma cells

secrete antibodies

What are the components of the extracellular matrix?

Ground substance, collagen fibers, elastic fibers, reticular fibers

Ground substance

between all cells and fibers in connective tissue, semi fluid/gelatinous, support/bind cells, store water, allow exchange between blood and cells

Loose connective tissue

many cells and fibers, loosely arranged, highly vascular

Dense connective tissue

fewer cells, many more fibers, stronger but less vascular

Cartilage

dense network of fibers in ground substance, cells located within small spaces called lacunae, avascular

Osseous tissue

bone; ecm contains numerous collagen fibers, enmeshed in calcium phosphate crystals

Liquid connective tissue

blood and lymph fluid; cells suspended in fluid ecm

Areolar tissue

loosely organized fibers, very vascular, lot of empty space

Adipose tissue

where adipocytes primarily occur, act as energy reserve of stored triglycerides

Reticular tissue

mesh of reticular fibers and fibroblasts, forms supportive framework for lymphs

Dense regular connective tissue

Densely packed, parallel collagen fibers, with condensed fibroblast nuclei

Dense irregular connective tissue

Densely packed, random collagen fibers, withstands unpredictable stressors

Elastic connective tissue

consists of freely branching elastic fibers and fibroblasts in between spaces, found in arteries

Cartilage

made by chondrocytes, found in lacuna, hyaline most abundant

Hyaline cartilage

clear, glassy, found supporting larynx

Fibrocartilage

clusters together, easier to see fibers, resists compression, found in intervertebral discs

Elastic cartilage

very dark stain, found in external ear

Marafin syndrome

genetic defect in fibrillin production, elastic tissue keeps stretching and doesn’t contract

Easily dislocates joints, tall, slender