Bell Work What is connective tissue? Where can it be found?

Bell Work

What is connective tissue? Where can it be found?

Connective Tissue Most diverse and

abundant tissue Main classes:

Connective tissue proper

CartilageBone tissueBlood

Connective Tissue- General Features

Components of connective tissue:Cells (varies according to tissue)Extracellular Matrix (in btw. Cells)

○ Protein Fibers ○ Ground substance

Other Characteristics:Not on body surfacesHighly vascular (except cartilage)

Connective Tissue Cells1. “Blast” Cells

Immature class of cells- blast cells have ability to divide & secrete extracellular matrix

Called:○ Fibroblasts in loose & dense connective tissue○ Chondroblasts in cartilage○ Osteoblasts in bone Once EC matrix is

produced, “blast” cells become “cyte” cells &

maintain the matrix

Connective Tissue Cells2. Fibroblasts- found in most connective

tissue,large/flat & branching; secrete fibers and EC matrix

3. Adipocytes- fat cells (deep to skin)

4. Mast cells- help in the body’s reaction to injury & infection (alongside blood vessels)

Produce histamine which dilates vessels

5. WBCs- fight pathogen invasion & inflammationMacrophages- engulf bacteriaPlasma Cells- develop from a WBC & they secrete

antibodies (neutralize foreign substances)

Connective Tissue Cells

Extracellular Matrix Definition: material btw cells Functions:

Supports cells/ binds cells togetherStores waterProvides a medium for exchange of substances

btw. cells & blood Components:

Fibers & Ground Substance

ECM Fibers- strengthen & support connective tissue

1. Collagen strong & resist pulling forces Not stiff thus flexible Found in cartilage, tendons, ligaments & bone

2. Elastic Provides strength & stretching Found in skin, blood vessels & lungs

3. Reticular Primary support & strength tissue Thinner than collagen fibers; branching networks Covers many organs (spleen, liver, lymph nodes)

Collagen Fibers

Elastic Fibers

Reticular Fibers

Ground Substance- connective tissue btw. cells

Characteristics:May be fluid, semifluid, gelatinous, or calcified

Composed of Glycosaminoglycans (GAGs) Polysaccharides Attract water Lubricate/support

Types: Chondroitin Sulfate- supports/adheres skin,

cartilage, tendons, bone & blood vessels Hyaluronic Acid- slippery & binds cells together,

lubricates joints, & maintains structure shape

Do Now:

What components make up extracellular matrix? Describe

each component.

Entrance Slip

1. Name three cells found in connective tissue?

2. What type of fiber has characteristics of strength and flexibility?

3. What is ground substance? Give a characteristic of it.

Connective Tissue Proper Loose Connective Tissue- loosely

intertwined fibers btw. cellsAreolarReticularAdipose

Dense Connective Tissue- thicker, denser fibers btw. fewer cells RegularIrregularElastic

Areolar Connective Tissue Description

Gel-like matrix w/:○ 3 Fibers: collagen, reticular, & elastic for support○ Ground substance is made up by many GAGs

Cells – fibroblasts, macrophages, mast cells, white blood cells, adipocytes

Function Wraps & cushions organsBinds the skin to underlying organs & fills space

between musclesImportant role in inflammation main battlefield in fight

against infection

Areolar Connective Tissue

Location Widely distributed under epithelia (has many blood

vessels so it nourishes epithelial cells)Packages organsSurrounds capillaries

Adipose Tissue Description

Closely packed adipocytes Nucleus pushed to one side

by fat droplet Function

Provides reserve food fuelInsulates against heat lossSupports & protects organs

LocationFound by areolar tissueUnder skin- insulates the

body & protects organsCushions jointsAround kidneys, between

muscles, behind eyeballs, within abdomen and in breasts

Reticular Connective Tissue

Description – network of reticular fibers in loose ground substance

Function – form a soft, internal skeleton (stroma- covers soft organs)

Location – lymphoid organs Lymph nodes, bone

marrow, and spleen

Dense Regular Connective Tissue

DescriptionParallel collagen fibersFibroblasts and some elastic fibersPoorly vascularized

FunctionAttaches muscle to boneAttaches bone to boneWithstands great stress in

one direction Location

Tendons and ligamentsFascia around muscles

Dense Irregular Connective Tissue

Description Irregularly arranged collagen

fibers Some elastic fibers and

fibroblasts Function

Withstands tension Provides structural strength

Location Dermis of skin Heart valves Surrounds cartilage & bone Submucosa of digestive tract Fibrous capsules of joints and

organs

Elastic Connective Tissue

Description Branching elastic fibers Some fibroblasts

Function Very elastic Can recoil to its original shape

after being stretched Location

Lung tissue Elastic arteries Vocal chords Ligament btw. vertebrae

Connective Tissue Catch Phrase Set the timer. Give the stack of cards to someone

on Team 1. One person from Team 1 will try to give their team mates clues to their phrase. If Team 1 guesses the phrase, Team 2 gets the stack of cards and tries to guess their phrase.

 Continue the game by going back and forth, as each team guesses the correct phrases. If the buzzer sounds during your turn, the other team gets a point and has the chance to earn a bonus point if they guess your phrase.

Bell Work

What are the three types of loose and dense

connective tissue?

Cartilage Characteristics:

Firm, flexible tissueContains no blood vessels or nervesMatrix contains up to 80% waterMainly collagen & elastic fibersCell type – chondrocyte

Types:HyalineFibrocartilageElastic

Hyaline Cartilage Description

Collagen fibers not in the matrix (hyaline = glassy)

Chodroblasts produce matrixChondrocytes lie in lacunae (space in mature

cartilage) Function

Supports and reinforcesResilient cushion/ Resists repetitive stressReduces friction

Hyaline Cartilage Location

Fetal skeletonEnds of long bonesCostal cartilage of ribsCartilages of nose tip,

trachea, and larynxJoints

*weakest of the 3 cartilages

Fibrocartilage Description

Matrix similar, but less firm than hyaline cartilage

Thick collagen fibers predominate in matrix w/ scattered chondrocytes

FunctionTensile strength w/ ability

to absorb compressive shock

LocationIntervertebral discsPubic symphysis (where hips

join)Discs of knee joint

*strongest type of cartilage

Elastic Cartilage Description

More elastic fibers in matrix w/ chondrocytes

Function Maintains shape of

structureAllows great flexibility

LocationSupports external earEpiglottis

Bone Tissue Function

Supports and protects organsProvides levers and

attachment site for musclesStores calcium and other

mineralsStores fatMarrow is site for blood cell

formation Characteristics

ETC matrix= lamellae rings of mineral salts

Lacunae- spaces in lamellae containing osteocytes

Location Bones

Blood Tissue Description

red and white blood cells in a fluid matrix

Functiontransport of respiratory

gases, nutrients, and wastes Location

within blood vessels Characteristics

An atypical connective tissue

Consists of cells surrounded by nonliving matrix (blood plasma- mainly water & dissolved nutrients)

Do Now:

What is the proper name of a bone cell, and what is the

name of the space in which a bone cell lies?

Do Now:

What are the three types of dense connective tissue?

Muscle Tissue Types

Skeletal muscle tissueCardiac muscle tissue Smooth muscle tissue

Skeletal Muscle Tissue

CharacteristicsLong, cylindrical cellsMultinucleateObvious striations

Function Voluntary movementManipulation of

environmentFacial expression

LocationSkeletal muscles

attached to bones (occasionally to skin)

Long, cylindrical cells that tend to have more than one nuclei.

Cardiac Muscle Tissue Function

Contracts to propel blood into circulatory system

CharacteristicsBranching cellsUninucleateIntercalated discs

LocationOccurs in walls of heart

Long, cylindrical cells that are shorter than skeletal muscle cells.

They have only one nucleus per cell.

Smooth Muscle Tissue Characteristics

Spindle-shaped cells withcentral nuclei

Arranged closely to form sheets

No striations Function

Propels substances along internal passageways

Involuntary control Location

Mostly walls of hollow organs

These cells are tapered at the ends, giving them a spindle appearance. They have one

nucleus and are not striated.

Nervous Tissue Function

Transmit electrical signals from sensory receptors to effectors

LocationBrain, spinal cord, and

nerves Description

Main components of brain, spinal cord, & nerves

Contains two types of cells○ Neurons – excitatory cells○ Supporting cells (neuroglial

cells)

Neurons consist of the cell body, which does basic cell activities, and dendrites (which receive impulses) and

axons (one per cell, conducting impulses away from cell body).

Tissue Response to Injury

Inflammatory response – non-specific, local responseLimits damage to injury site

Immune response – takes longer to develop and very specificDestroys particular microorganisms at site of

infection

The Tissues Throughout Life

At the end of second month of development:Primary tissue types have appearedMajor organs are in place

AdulthoodOnly a few tissues regenerateMany tissues still retain populations of stem cells

○ Stem cells- divide/ differentiate into specialized cell types

With increasing age:Epithelia thin Collagen decreasesBones, muscles, and nervous tissue begin to atrophyPoor nutrition and poor circulation – poor health of tissues

Covering and Lining Membranes

Combine epithelial tissues and connective tissues

Cover broad areas within body Consist of epithelial sheet plus

underlying connective tissue

Three Types of Membranes

Cutaneous membrane – skin Mucous membrane

Lines hollow organs that open to surface of bodyAn epithelial sheet underlain with layer of lamina

propria Serous membrane – slippery membranes

Simple squamous epithelium lying on areolar connective tissue

Line closed cavities○ Pleural, peritoneal, and pericardial cavities