Tissues, Glands, and Membranes

Anatomy unit 1

Four Basic Types of Tissues

• Epithelial

• Connective

• Muscle

• Nervous

Epithelial Tissue General Characteristics

• Covers internal and external body surfaces

• Comprises major tissue of glands

Epithelial Tissue Unique Characteristics

• Mostly of cells with very little ECM

• Lacks blood vessels

• Gases, Nutrients, and waster diffuse across basement membrane

• Free Membrane doesn’t touch any other cell

Functions of Epithelial Tissue

• Protect

• Barrier

• Exchange substances: Oxygen and Carbon dioxide

• Secretion

• Absorption

Classification of Epithelia

• Simple

• Stratified (skin)

• Squamous

• - Keratinized

• - Non Keratinized (moist)

• Cuboidal

• Columnar

• Pseudo-stratified (with Cilia, trachea)

• Transitional (bladder)

Single Layers functions

• Diffusion

• Filtration

• Secretion

• Absorption

Multiple Layers Functions

• Protect

• Damaged Cells replaced

Squamous Functions

• Diffusion

• Filtration

Cuboidal/Columnar Functions

• Secretion

• Absorption

• More complex = more complex job

Free Cell surface Function

• Smooth: reduces friction

• Microvilli: Increases surface area so more absorption or secretion

• Cilia: grab and propel materials

• Goblet cells: secrete Mucus

Tight Junctions

Bind adjacent cells together

• prevent passage of material

Desmosomes

• Bind cells to on another

Hemidesmosomes

Anchor cells to basement membrane

Gap Junctions

Allow passage of Molecules

Glands

• Multicellular Structure secreting substance onto a surface, cavity, or blood

Exocrine Gland

• With ducts

• Secretions pass through ducts

endocrine gland

• Without ducts

• Hormones are secreted into blood

Types of Exocrine Gland

• Simple – ducts w/o branches

• Compound – ducts w/ branches

• Tubular – tubes

• Acinus/alveolus – saclike

Connective Tissue

• Most abundant

• few cells in large amounts of ECM

Components of ECM

• Protein Fibers

• Ground Substance

• Fluid

Three types of protein Fibers

• Collagen Fibers: Rope-like, resist stretching

• Reticular Fibers: short collagen fibers, branched

• Elastic fibers: coiled, stretch and recoil

ground substance

combination of proteins and other molecules: can be fluid or solid

proteoglycans

protein complex that traps water

blast

builds

cyte

mature cells

clast

breaks down

Macrophage

large mobile cells that eat foreign substances found in connective tissue

mast cells

non-motile cells that release chemicals that promote inflammation

functions of connective tissue

• enclose organs and separate organs

• connect tissues

• support and movement

• storage

• cushion and insulation

• transportation: blood transport gases

• protection

Erythrocytes & Leukocytes

blood

Loose connective tissue

• ECM has fibrocytes, fluid filled

• forms thin membranes between organs and binds them

• superficial layer of dermis

Adipose connective tissue

• very little ECM, collagen and elastic fibers. Filled with lipid

• stores fat

• beneath the skin, breasts

Dense connective tissue

• ECM is collagen

• Withstands pulling forces, resists stretching

• tendons, ligaments

Dense elastic connective tissue

• ECM collagen and elastic fibers

• Stretches and recoils

• Vertebral ligaments, vocal cords

Cartilage / Chondrocytes

• Has collagen fibers

• water

• no blood vessels

Three types of cartilage

• Hyaline Cartilage - nose

• Elastic Cartilage -

• Fibrocartilage - joints, intervertebral discs

Hyaline Cartilage

• Supports structures, forms smooth joint surfaces

• In ribs, nose, bone ends

Fibrocartilage

• Somewhat flexible

• withstand great pressure

• connect structures

• intervertebral disks

Elastic Cartilage

• Abundant elastic fibers

• more flexibility

• external ears

bone

• strength, support, protect organs

• all bones in body

blood

• Transport oxygen, hormones

• in blood vessels, produced by red bone marrow

Muscle Tissue

• Can contract

• Enables movement

• Skeletal, smooth, and cardiac

Skeletal Muscle

• Striated Muscle

• body movement and voluntary control

• attached tp b

Cardiac Muscle

• Striated, branched

• pump blood, involuntary control

• heart

smooth muscle

• cells tapered at each end, not striated

• regulates organ size, forces fluid through tubes

• Walls of hollow organs and tubes

Nervous Tissue

• Forms brain, spinal cord, peripheral nerves

• emotions

• reasoning skills

Action Potentials

• Electrical signals responsible for communication between neurons and other cells

Neurons

Conduct action potential

Cell body

Contains nucleus, sit of general cell functions

Dendrite

conduct a.p toward cell body

Axon

conduct a.p away from cell body

Neuroglia

support cells by nourish, protect, insulate

Membranes

• thin sheet layer of tissue covering a structure

• made of epithelium and connective tissue

Types of Membranes

• Mucous membranes

• Serous membranes

• skin/ cutaneous membranes

• synovial membranes

• periosteum

Mucous membrane

• layer of fluid

• line cavities that opening to outside of body: digestive, reproductive

• glands secrete mucus

• protection

• absorption

• digestion

Serous Membranes

• Line trunk cavities, cover organs

• Mucous glands secrete serous fluid

• Prevent damage from abrasion between organs in thoracic and abdominopelvic cavities

Skin/Cutaneous membranes

• Stratified squamous epithelium and dense connective tissue

• skin

Synovial membranes

• Connective tissue

• line joint cavities

Periosteum

• connective tissue

• surrounds bone

Injury/Inflammation in tissues

• In response to tissue damage

• mobilize body’s defenses

• destroy microorganisms

• pave way for tissue repair

Symptoms of inflammation

• Redness

• Heat

• Swelling

• Pain

• Disturbance of function

Mediators of inflammation

• Histamines, Cytokines, prostaglandins, leukotrienes, bradykinin

Edema

Swelling

Fibrin

protein that walls off site

Neutrophils

ingest bacteria

Macrophage

ingest tissue debris

Pus

mixture of dead neutrophils

Regeneration

Same types of cells takes place of previous cells

Replacement

different type of tissue develops, forms scars

Labile Cells

divide continuously through life

• Skin

Stable Cells

don’t actively divide but can after injury

• Connective tissue

Permanent cells

little to no ability to divide

• Neurons, skeletal muscle

Steps for tissue repair

• Clot

• Scab

• Blood vessel dilation

• Fibrin

• Epithelium replaced

• scab sloughs

• fibroblasts

• wound contracture