Exercise 6: Classification of Tissues

Skeletal muscle

"meat" or flesh of body; attached to skeleton; under voluntary control and its contraction moves the limbs and other external body parts

How many basic types of muscle tissue exist?

3 cardiac, smooth, skeletal

How many primary tissue types are found in the human body?

4 epithelial connective muscular neural

Connective tissue

A body tissue that provides support for the body and connects all of its parts

Connective tissue proper: dense irregular connective tissue function

Able to withstand tension exerted in many directions; provides structural strength

Simple columnar epithelium function

Absorption; secretion of mucus, enzymes, and other substances; ciliated type propels mucus by ciliary action

Types of loose connective tissues

Aerolar, adipose, and reticular

Simple squamous epithelium function

Allows materials to pass by diffusion and filtration in sites where protection is not important; secretes lubricating substances in serosae

Connective tissue proper: elastic connective tissue function

Allows recoil of tissue following stretching; maintains pulsatile flow of blood through arteries; aids passive recoil of lungs following inspiration

Cartilage: hyaline

Amorphous but firm matrix; collagen fibers form an imperceptible network; chondroblasts product matrix and, when mature (chondrocytes), lie in lucanae

Covering and lining epithelia are classified according to two criteria

Arrangement or relative # of layers and cell shape

Cardiac muscle function

As it contracts, cardiac muscle propels blood into the circulation; involuntary control

Connective tissue proper: dense regular connective tissue function

Attaches muscles to bones or to other muscles; attaches bones to bones; withstands great tensile stress when pulling force is applied in one direction

Bones (osseous tissue) function

Bone supports and protects (by enclosing); provides levers for the muscles to act on; stores calcium and other minerals and fat; marrow inside bones is site for blood cell formation

Osseous tissue

Bone tissue

Bones (osseous tissue) location

Bones

Connective tissue examples

Bones, ligaments, tendons, blood

Nervous tissue location

Brain, spinal cord, and nerves

Cardiac muscle

Branching, striated, generally uninucleate cells that interdigitate at specialized junctions called intercalated discs

Basement membrane

Cells at the base of an epithelial layer are attached to this; amorphous material secreted partly by epithelial cells and connective tissue cells

Ground substance

Composed chiefly of interstitial fluid, cell adhesion proteins, and proteoglycans

Stratified epithelia

Consist of 2 or more layers of ells

Simple epithelia

Consist of one layer of cells attached to basement membrane

Blood location

Contained within blood vessels

Connective tissue proper: elastic connective tissue

Dense regular connective tissue containing a high proportion of elastic fibers

Types of dense connective tissues

Dense regular, dense irregular, and elastic

Mesenchyme

Embryonic connective tissue that arises from mesoderm and produces all types of connective tissues

Embryonic connective tissue: Mesenchyme

Embryonic connective tissue; gel-like ground substance containing fibers; star-shaped mesenchymal cells

4 primary tissue types

Epithelium, connective tissue, nervous tissue, and muscle

Connective tissue proper: loose connective tissue, reticular function

Fibers form a soft internal skeleton that supports other cell types, including white blood cells, mast cells, and macrophages

Connective tissue proper: dense irregular connective tissue locoation

Fibrous capsules of organs and of joints; dermis of the skin; submucosa of digestive tract

Cartilage: hyaline location

Forms most of the embryonic skeleton; covers ends of long bones in joint cavities; forms coastal cartilages of ribs; cartilages of the nose, trachea, and larynx

Smooth muscle

Found mainly in walls of hollow organs; two layers that run at right angles to eachoter

Connective tissue proper: loose connective tissue, areolar

Gel-like matrix with all three fiber types; cells: fibroblasts, macrophages, mast cells, and some white blood cells

Stratified cuboidal epithelium

Generally two layers of cubelike cells

Mesenchyme function

Gives rise to all other connective tissue types

Tissues

Groups of cells that are anatomically similar and share a function

Bones (osseous tissue)

Hard, calcified matrix containing many collagen fibers; osteocytes lie in lacunae; very well vascularized

Muscle tissue

Highly specialized to contract and produces most types of body movement

Skeletal muscle location

In skeletal muscles attached to bones or occasionally to skin

Cartilage: fibrocartilage location

Intervertebral discs; pubic symphsysis; discs of knee joint

Reticular fibers

Join connective tissue to adjacent tissues (fine collagen)

Simple squamous epithelium location

Kidney glomeruli; air sacs of lungs; lining of heart, blood vessels, and lymphatic vessels; lining of body cavity (serosae)

Simple cuboidal epithelium location

Kidney tubules; ducts and secretory portions of small glands; ovary surface

Stratified cuboidal epithelium location

Largest ducts of sweat glands, mammary glands, and salivary glands

Dense regular connective tissue

Ligaments and tendons that bind the bones together or connect skeletal muscles to bones

Transitional epithelium location

Lines the ureters, urinary bladder, and part of urethra

Skeletal muscle

Long, cylindrical, multinucleate cells; obvious striations

Connective tissue proper 2 subclasses

Loose connective tissues (areolar, adipose, and reticular) and dense connective tissues (dense regular, dense irregular, and elastic)

Endocrine glands

Lose their surface connection as they develop; ductless glands; secrete hormones into the extracellular fluid, and from there the hormones enter the blood or lymphatic vessels that weave through glands

Connective tissue proper: loose connective tissue, reticular location

Lymphoid organs (lymph nodes, bone marrow, and spleen)

Nervous tissue

Made up of neuroglia and neurons

Cartilage: elastic function

Maintains shape of a structure while allowing great flexibility

Connective tissue proper: loose connective tissue, adipose

Matrix as in areolar, but very sparse; closely packed adipocytes, or fat cells, have nucleus pushed to the side by large fat droplet

Cartilage: fibrocartilage

Matrix similar to but less firm than matrix in hyaline cartilage; thick collagen fibers predominate

Smooth muscle location

Mostly in walls of hollow organs

Connective tissue proper: loose connective tissue, reticular

Network of reticular fibers in a typical loose ground substance; reticular cells lie on the network

Nervous tissue

Neurons are branching cells; cells processes that may be quite long extend from the nucleus-containing cell body; also contributing to nervous tissue are nonexcitable supporting cells

Nervous tissue function

Neurons transmit electrical signals from sensory receptors and to effectors; supporting cells support and protect neurons

Pseudostratified columnar epithelium location

Nonciliated type in male's sperm-carrying ducts of large glands; ciliated variety lines the trachea, most of the upper respiratory tract

Simple columnar epithelium location

Nonciliated type lines most of digestive tract (stomach to rectum), gallbladder, and excretory ducts of some glands; ciliated variety lines small bronchi, uterine tubes, and some regions of uterus

Stratified squamous epithelium location

Nonkeratinized type forms moist linings of esophagus, mouth, and vagina; keratinized variety forms epidermis of skin, a dry membrane

Extracellular matrix

Nonliving material between the cells that distinguishes connective tissue from all other tissues; responsible for strength associated with connective tissue

Cardiac muscle

Only found in heart; as it contracts, the heart acts as a pump, propelling the blood into the blood vessels; has striations

Transitional epithelium

Only found in urinary system organs subjected to stretch, such as the bladder

Epithelial tissue distinguishing characteristics

Polarity; specialized contacts; supported by connective tissue; avascular but innervated; regeneration

Mesenchyme location

Primarily in embryo

Connective tissue proper: dense irregular connective tissue

Primarily irregularly arranged collagen fibers; some elastic fibers; major cell type is the fibroblast

Connective tissue proper: dense regular connective tissue

Primarily parallel collagen fibers; a few elastic fibers; major cell type is the fibroblast

Connective tissues

Primarily protect, support, insulate, and bind together other tissues of body

Smooth muscle function

Propels substances or a baby along internal passageways; involuntary control

Four main types of adult connective tissue

Proper, cartilage, bone, and blood

Osseous tissue (bone)

Protect and support other body tissues and organs

Stratified cuboidal epithelium function

Protection

Epithelial functions

Protection, absorption, filtration, excretion, secretion, and sensory reception

Stratified columnar epithelium function

Protection, secretion

Stratified squamous epithelium function

Protects underlying tissues in areas subjected to abrasion

Adipose (fat) tissue

Provides insulation for body tissues and a source of stored energy

Connective tissue proper: loose connective tissue, adipose function

Provides reserve fuel; insulates against heat loss; supports and protects organs

Stratified columnar epithelium location

Rare in body; small amounts in male urethra and in large ducts of some glands

Blood

Red and white blood cells in a fluid matrix (plasma)

Transitional epithelium

Resembles both stratified squamous and stratified cuboidal; basal cells cuboidal or columnar; surface cells dome shaped or squamouslike, depending on degree of organ stretch

Exocrine glands

Retain their ducts, and their secretions empty through these ducts either to the body surface or into body cavities (sweat and oil glands, liver, and pancreas)

Pseudostratified columnar epithelium function

Secretes substances, particularly mucus; propulsion of mucus by ciliary action

Simple cuboidal epithelium function

Secretion and absorption

Stratified columnar epithelium

Several cell layers; basal cells usually cuboidal; superficial cells elongated and columnar

Epithelial tissue

Sheet of cells that covers a body surface or lines a body cavity

Cartilage: elastic

Similar to hyaline cartilage, but more elastic fibers in matrix

Pseudostratified columnar epithelium

Single layer of cells of differing heights, some not reaching the free surface; nuclei seen at different levels; may contain mucus-secreting goblet cells and bear cilia

Simple cuboidal epithelium

Single layer of cubelike cells with large, spherical central nuclei

Simple squamous epithelium

Single layer of flattened cells with disc-shaped central nuclei and sparse cytoplasm; simplest of epithelia

Simple columnar epithelium

Single layer of tall cells with round to oval nuclei; some cells bear cilia; layer may contain mucus-secreting unicellular glands

3 types of muscle tissue

Skeletal, cardiac, smooth

Lucanae

Small cavities in bone that contain osteocytes

This type of muscle tissue is found in the walls of hollow organs. It has no striations and its cells are spindle shaped.

Smooth muscle

Areolar connective tissue

Soft packaging material that cushions and protects body organs

Neuroglia

Special supporting cells that protect, support, and insulate more delicate neurons

Intercalated discs

Specialized connections between myocardial cells containing gap junctions and desmosomes

Smooth muscle

Spindle-shaped cells with central nuclei; no striations; cells arranged closely to form sheets

Epithelial tissues can be classified according to cell shape. ___________ epithelial cells are scale like and flattened

Squamous

Based on cell shape, epithelia are classified into three categories

Squamous (scalelike), cuboidal (cubelike), columnar (column-shaped)

Transitional epithelium function

Stretches readily and permits distension of urinary organ by contained urine

Elastic fibers

Stretchy yellow connective tissue fibers consisting of the protein elastin

Cartilage: hyaline function

Supports and reinforces; serves as resilient cushion; resists compressive stress

Cartilage: elastic location

Supports external ear (auricle); epiglottis

Connective tissue proper: dense regular connective tissue location

Tendons, most ligaments, aponeuroeses

Cartilage: fibrocartilage function

Tensile strength with ability to absorb compressive shock

Stratified squamous epithelium

Thick membrane composed of several layers; in the keratinized type, the surface cells are full of keratin and dead; basal cells are active in mitosis

Pseudostratified epithelium

Tissue with cells that appear to be in layers, but are not

Blood function

Transport of respiratory gases, nutrients, wastes, and other substances

T or F: Blood is a type of connective tissue

True

T or F: Endocrine and exocrine glands are classified as epithelium because they develop from epithelial membranes.

True

Connective tissue proper: loose connective tissue, adipose location

Under skin; around kidneys and eyeballs; within abdomen; in breasts

Skeletal muscle function

Voluntary movement; locomotion; manipulation of the environment; facial expression; voluntary control

Cardiac muscle location

Walls of heart

Connective tissue proper: elastic connective tissue location

Walls of large arteries; within certain ligaments associated with the vertebral column; within walls of bronchial tubes

Connective tissue proper: loose connective tissue, areolar location

Widely distributed under epithelia of body

Connective tissue proper: loose connective tissue, areolar function

Wraps and cushions organs; its macrophages phagocytize bacteria; plays important role in inflammation; holds and conveys tissue fluid

Collagen fibers

are long, straight, unbranched and are the most common type of fiber (white)

Neurons

highly specialized to receive stimuli and to generate electrical signals that may be sent to all parts of body