Tissues Anatomy

Tissues

Epithelial Tissue General Characteristics:

Found throughout the body

covers all body surfaces both inside and out.

Main glandular tissue.

Attached to connective tissue by a basement

membrane.

Avascular- no blood supply (absorption/diffusion)

Regeneration - Cells reproduce rapidly (rapid

healing).

Cells tightly packed together (cell junctions)

The ink of tattoos must be injected

below the basement membrane.

Cell Junctions

Where

does all

the dead

skin you

shed go?

It takes about 27

days for the

outer layer of

skin to shed and

be replaced;

that works out to

1.5 pounds of

skin cells per

year.

Function

Protection

secretion

absorption/ excretion (permeability)

sensory perception

Epithelial tissue is named based

on its description

simple = single layer

stratified = multiple layers

squamous = flat

cuboidal = square

columnar = column (rectangle)

Simple Squamous

• Function: diffusion and filtration.

• Air sacs in lungs, walls of capillaries

Simple Cuboidal

• Function:

Secretion and

Absorption

• Found in kidneys

tubules, ducts

and covering the

ovaries

Stratified cuboidal epithelium

• Rare: ducts of sweat glands and mammary glands

Simple Columnar

• Function: Secretion

and absorption

• Found in Digestive

tract and uterus

• *Contains goblet cells

to secrete mucus

• *Can have microvilli

Tissues often come in

layers on the body -

superficial cuts on the

skin may need to be

stitched if they also go

through the underlying

tissue.

This will definitely need

stitches!

Stratified Squamous

• Multi layer, thicker

squamous tissue

• Functions in protection

• Found in skin and

mouth

Pseudostratified Columnar • Single layer

• nuclei are uneven which gives it a layered

appearance

• Can have goblet cells and cilia • Function:

secretion and cilia

aided movement

• Location: lining air

passages and

tubes of the

reproductive

system

Cigarette Smoke

Cystic Fibrosis

Transitional Epithelium

• Stretchable

• Blocks diffusion (no

leaking)

• Found in the urinary

bladder

Glandular Epithelium

• Cells are specialized to

produce and secrete substances

• They make up the GLANDS

• exocrine glands (ducts)

• Sweat, saliva, tears

• endocrine glands (ductless)

• hormones

• Make an Ear

• Printing Organs

Identify the tissues

Connective Tissue

• Ex: Bone, Fat, Blood

• 3 basic components

• 1) specialized cells

• 2)Extracellular protein fibers

• 3) Fluid: ground substances

• Fibers + ground substances = Matrix (surrounds cells)

• Matrix = most of the volume

Connective Tissue General Characteristics:

Most abundant tissue in your body

Binds structures together

Provides support, protection, framework, fills space,

stores fat, produces blood cells, fights infection, and

helps repair tissue.

Composed of more scattered cells with abundant

intercellular material ' matrix

Made up of a ground substance (fluid, semi-solid) and

fibers

Most has a good blood supply

Cells can reproduce

Connective Tissue Classification

• Connective Tissue Proper

• Many types of cells and extracellular fibers in a syrupy

ground substance

• Loose and Dense Connective Tissue

• Ex: adipose tissue and tendons

• Fluid Connective Tissue

• Cells in a watery mixture that contains proteins

• Blood and Lymph

• Supporting Connective Tissue

• Fewer types of cells and more densely packed fibers

• Cartilage and Bone

Types of Cells in Connective Tissue

• Fibroblasts

• only cells always present

• Make ground substance & extracellular fibers

• Macrophages

• Amoeboid, scattered

• Tissue defense- engulf pathogens or damaged cells

• Adipocytes

• Adipose/fat cells

• Mesenchymal

• Stem cells

• Respond to injury – differentiate into fibroblasts,

macrophages, or other connective tissue

Types of Cells in Connective Tissue

• Fibroblasts (produce fibers)

Collagenous (bones,

ligaments, tendons)

Elastic (respiratory)

Types of Cells in Connective Tissue (2)

• Melanocytes

• Synthesize and store pigment melanin (skin, eye)

• Mast cells

• Near blood vessels

• Cytoplasm contains histamin & heparin – stimulate

inflammation after injury

• Lymphocytes

• Migrate – increase in damaged tissue

• Some develop into plasma cells – defend against disease

• Microphages

• Move through tissue – congregate where injury

• Respond to chemicals released by macrophages and mast

cells

Types of Fibers in Connective Tissue • Collagen

• Long, straight, branched

• Most common

• Fibrous proteins wound like a rope (stronger than steel – from end to end)

• Ex: tendons (muscle to bone), ligaments (bone to bone)

• Recticular

• thinner, branching, interwoven framework (stroma)

• Resist forces from many directions

• Stabalizes functional cells (parenchyma), blood vessels, nerves, etc. of organs

• Elastic

• Contain elastin

• Branched & wavy

• Stretch and return to original length

• Elastic ligaments – ex: vertebrae

Main types of Fibers Collagenous fibers - strong

and flexible

bones, tendons and

ligaments

Elastic fibers - very flexible

ears and vocal cords

Categories of Connective Tissue

Connective Tissue Proper: Loose Connective Tissue

• Binds underlying

organs to skin and

to each other

• Forms delicate thin

membranes

throughout the

body

• Mucous tissue in

embryos, areolar,

adipose, reticular

(adults)

Loose Connective Tissue

• “Packaging materials” of the body

• Fill spaces; cushion and stabilize; support epithelia,

vessels, nerves; store lipids, route for diffusion

• Mucous connective tissue – embryo (including

umbilical cord)

• Adults: mesenchymal stem cells that assist in tissue repair

Loose Connective Tissue

• Areolar

• Least specialized

• open framework

• absorbs shock

• Padding

• Considerable movement

• Separate skin from deeper layers

• elastic fibers return it to original shape

• Extensive circulatory supply (site for injections)

Loose Connective Tissue

• Adipose

• Similar to Areolar Tissue

• More adipocytes

• Padding, absorb shock, insulate

• Common under skin of groin, sides, buttocks, breasts

• Fills bony sockets behind eyes

• Surrounds kidneys

• Below lining of pericardial and abdominal cavities

• White fat – pale, yellowish-white color

• Brown fat – shoulder blades/neck of young children –

vascularized with many mitochondria (break down to create

heat)

Loose Connective Tissue

• Reticular

• Spleen and liver and other organs

• Lymph nodes, bone marrow

• 3D network (stroma) to support functional cells of organs

Dense Fibrous Connective Tissue

Tendons =

muscles to bones

Ligaments =

bones to bones

Dense Regular Connective Tissue

• Collagen fibers are parallel

• Packed tightly

• Aligned with the forces applied to the tissue

• Tendon – muscle to bone

• Aponeurosis – tendinous sheet

• Ligament – bone to bone

Dense Irregular Connective Tissue

• Interwoven mesh, no pattern

• Support areas subject to stresses from many directions

• Gives skin strength (cured leather)

• Sheath around cartilages and bones

• Capsule – surround internal organs

• Encloses cavities of joints

Elastic Connective Tissue

• Dense regular connective tissue dominated by elastic

fibers

• Elastic ligaments – stabilize/position spine

Fluid Connective Tissue: Blood Tissue

• Blood – red, white, platelets

• Lymph – forms as interstitial fluid lyphatic vessels

cardiovascular system

• responds to signs of injury

• Primarily macrophages and microphages

Supporting Connective Tissue

• Cartilage and Bone

• Contain many fibers and often deposits of insoluble calcium salts

CARTILAGE

• Cartilage cells are called

chondrocytes

• -Occupy small chambers

called lacunae

• Provides support and

attachments, also cushions

bones

Hyaline Cartilage

• Covers ends of joints, nose and respiratory

passages, sternum

• Provides stiff, but flexible

support

• Reduces friction between

bones

Elastic cartilage • External Ear, larynx, epiglottis, auditory

canal

• Provides support, but tolerates

distortions (return to shape)

Fibrocartilage • Knees, pubic bones, intervertebral discs

• Tough, shock absorbing, resists

compression, prevents bone-to-bone

contact

Bone Tissue (Osseus) • Minerals organized around collagen fibers = strong &

flexible to resist shattering

• Osteocytes = bone cells

• Canaliculi = passageways to exchange materials with

blood

• Periosteum – assists in attachment of bone to

surrounding tissue

Membranes • Epithelia and Connective tissue combine to form membranes that

cover and protect structures and tissues

• Mucous / mucosae

• Line cavities that communicate with the exterior

• Digestive, respiratory, reproductive, urinary

• Kept moist at all times

• Serous

• Line sealed, internal divisions of the ventral body cavity

• Pleura, peritoneum, pericardium (parietal portion)

• Serosa (visceral portion) – covers visceral organs

• Transudate = fluid formed

• Minimize friction

Membranes (2)

• Cutaneous

• Skin – covers surface of the body

• Stratified squamous epithelium, areolar tissue, dense connective

• Thick, mostly waterproof, usually dry

• Synovial

• line join cavities (articulations – bones contact at joints)

Connective Tissue Framework

• Fasciae – connective tissue layers

• Superficial/subcutaneous/hypodermis

• Separates skin from tissue

• insulation

• Deep

• “plywood” alternate layers

• Tough capsule

• Subserous

• Separates deep fasciae from serous membrane (does not

become distorted)

Muscle Tissue - specialized for contraction

Skeletal muscle • Large muscle cells (up to 0.3m/1ft)

• Long/slender (muscle fibers)

• Multinucleated

• Incapable of dividing

• New cells made by satellite cells

• Stem cells in skeletal tissue

• Actin and Myosin

• Striated voluntary muscle

Cardiac muscle • Only in heart

• Cardiocyte (cell) = smaller than skeletal muscle

• 1-5 nuclei

• Intercalated discs – link cells together

• Branching

• Lack satellite cells – cannot regenerate

• Pacemaker cells – regular rate of contraction

• Striated involuntary muscle

Smooth muscle • Walls of blood vessels and organs

• Small, tapered cells

• Can divide

• Nonstriated involuntary muscle

Nerve/Neural/Nervous Tissue

• 98% in brain & spinal cord

• Electrical impulses (transmembrane

potential)

• Neurons

• Main cell

• Neuroglia

• Supporting cells

• Longest cells in body (nerve fibers)

• Cannot divide/regenerate

• Cell body, dentrites (to cell),

axon (away)

Nervous tissue

Unit 2: Cells and Tissues

• The student will be able to…

• Identify cell organelles, describe their function, explain how organelles

work together

• Identify parts of the cell membrane and explain their function

• Identify the steps of the cell cycle and the main actions that take place

in each

• Describe how cells are organized into tissues.

• Describe the structure, function and characteristics of epithelial tissue.

• Identify, compare and contrast the six different kinds of connective

tissue.

• Describe and identify the four different kinds of membranes.

• Distinguish among the three different kinds of muscle tissue.

• Describe the general characteristics and functions of nervous tissue