Tissues

4 types of tissues

Epithelial, connective, muscular, nervous

Epithelial tissue

• lines surfaces and secretes substances

• protection and transportation

Surface epithelium

• lines surface

• outer covering of skin and some internal organs

• inner lining of structures

• vessels, ducts, body cavities, lining of resp, digest, urinary, genital systems

Glandular epithelium

• secreting portion of glands

• thyroid, adrenal, sweat, digestive

• protects and secretes and absorbs and excretes

Basement membrane

• layer between epithelium and connective

• basal and reticular laminar

• anchors and forms surface for migrations

Squamous

flat

• best for transportation

Cuboidal

cube

• secretes or absorbs

• not in areas that need protection

• may have microvilli

Columnar

tall

• protect tissues

• may have cilia or microvilli

• secretion or absorption

Transitional

changes shape

• bladder

Simple epithelium

Single layer

• diffusion, filtration, secretion/absorption, osmosis

Pseudostratified

Pretends to have multiple layers

Stratified

2 or more layers

• protects underlying tissues

Simple squamous

found in organs where transportation across ET is critical

Endothelium

Simple squamous

• lines heart, blood vessels, lymphatic vessels

Mesothelium

simple squamous

• forms epithelial layer of serous membranes

Nonciliated simple columnar epithelium

lines digestive canal, ducts of many glands, gallbladder

• secretes and absorbs

Ciliated simple columnar epithelium

places where material needs to be moved along

• respiratory tract, fallopian tubes

• coughing, sneezing speed up movement of cilia

Keratinized stratified squamous

Superficial layer of skin

• damage is high but must remain dry

Nonkeratinized stratified squamous

Lines wet surfaces

• high damage but must remain wet

Edocrine

secretes hormones directly into blood

• insulin, adrenaline, pituitary hormones

Exocrine

secretes substances onto a surface

• gastric juice, ear wax, sweat

Connective tissue

much extracellular matrix, widely scattered cells

• most abundant

• found in all organs

• protection and transport

• contains and distributes blood vessels

• stored energy and immune response

Extracellular matrix

material located between widely-spaced cells

• protein fibers & ground substance

Ground substance

may be fluid, semifluid, gelatinous, or calcified

• supports cells, binds, stores water, exchange of substances

Fibers

• collagen

• elastic

• reticular

Collagen fibers

strong and flexible bundles of protein collagen

• bones, cartilage, tendons, ligaments

• most abundant protein

Elastic fibers

Stretchy & made of proteins, elastin and fibrillin

• skin, blood vessels, lung tissue

Reticular fibers

Invisible framework of many small organs

• spleen, lymph nodes

Loose CT

loosely arranged between cells

• areolar, adipose, reticular

Areolar CT

In and around nearly every body structure

• packing material

• strength, elasticity, support

• subcutaneous tissue, dermis of skin, around blood vessels

Adipose CT

• wherever areolar is located

• reduces head loss, energy reserve, protection, stem cells

  • subcutaneous tissue, around heart & kidneys, yellow BM, padding around joints, behind eyeball

Reticular CT

Forms stroma of organs, binds smooth muscle, filters blood cells in spleen, microbes in lymph nodes

Dense CT

dense collagen fibers that provide strength and flexibility

• Irregular and regular

Dense irregular CT

• fibers run in all directions

• sheets (fasciae), dermis of skin, pericardium of heart, peristomium of bone, joints

• pulling of strength in many directions

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Dense irregular CT

collagen fibers run parallel & provide strength

• tendons & ligaments

Specialized CT

Cartilage, fat, blood, bone

Cartilage

Dense network of collagen or elastic fibers embedded in chondroitin sulfate (gel of ground substance)

• strongest minus bone

Hyaline Cartilage

• gel ground substance

• ends of long bones, anterior ends of ribs, nose, throat tubes, fetal skeleton

• smooth surface for movement at joints

• weakest type

Fibrous Cartilage

• has chondrocytes among clearly visible thick bundles of collagen within EM

• lacks perichondrium

• pubic symphysis, invertebral discs, menisci of knee, tendons

• STRONGEST

Elastic cartilage

• chondrocytes in threadlike network of elastic within EM

• perichondrium

• lid of larynx, external ear, auditory tubes

• strength and elasticity

• maintains shape

Perichondrium

layer of dense irregular connective tissue that surrounds most types of cartilage in the body

• contains fibroblasts and chondroblasts

Bone connective tissue

Living tissue with dead, mineralized matrix

• compact of spongy

Compact bone tissue

• osteons that contain bone lamellae, lacunae, osteocytes, canaliculi, osteonic canals

• dense outer layer of bone

Spongy bone tissue

porous, inner network that reduces bone weight and houses bone marrow

• does not have osteons

Osteon

basic unit of compact bone

Bone lamellae

rings of EM that consist of mineral salts, mineralized bone matrix and collagen fibers

• responsible for compact nature of bone tissue

Bone lacunae

small spaces between lamellae that contain mature bone cells (osteocytes)

• fluid filled spaces

Bone canaliculi

little canals that project from lacunae

• contain processes of osteocytes

• routes for nutrients to reach osteocytes

• nutrient and waste transport

Osteonic canal

Contains blood vessels and nerves

• hollow center

Trabeculae

small, supportive tissue fibers that form a meshwork or scaffolding inside organs and bones

• in spongy bones

Fat connective tissue

energy storage molecule

• has no EM

Blood tissue

• liquid EM

• consists of blood plasma, RBC, WBC, platelets

  • In blood vessels and chambers of heart

Red blood cells

transport oxygen and some CO2

White blood cells

carry on pharyngomycosis and mediate allergic and immune system responses

Platelets

essential for blood clots

Lymph Plasma

• liquid EM

• several cells in clear liquid

• less protein than blood

• composition varies from one part to another

Membranes

• structural features that combine ET and CT

• lines surfaces and control passage of materials

• serous, mucous, cutaneous, synovial

Serous membrane

• lines cavities NOT open to exterior and covers organs

• 2 layers - parietal and visceral

• fluid in between

• pleura, pericardium, peritoneum

Mucous membrane

• lines cavities OPEN to exterior

• protects from dehydration and invasion

• digestive canal, respiratory, genital, urinary

• lamina

Cutaneous membrane

• skin, lines cavities open to exterior

• epidermis and dermis

Epidermis

keratinized stratified squamous epithelium

Dermis

dense irregular CT & areolar CT

Synovial membrane

• lines movable joints

• not open to exterior but doesn’t have epithelial lining

• secretes synovial fluid which lubricates

• egg

• discontinuous layer of cells

Muscular tissue

• movement caused by muscle

• skeletal, cardiac, smooth

Skeletal MT

• attached to bones by tendons

• motion, posture, heat, protection

• voluntary movements

Cardiac MT

• only in heart wall

• involuntary control

Smooth MT

• hollow organs

• no voluntary control

• iris, blood vessels, airways to lungs, stomach, etc

• motion

Nervous tissue

• neurons and neuroglin

• impulses and things like that idk