Bell Work
What is connective tissue?
Where can it be found?
Connective Tissue
 Most
diverse and
abundant tissue
 Main classes:
 Connective tissue
proper
 Cartilage
 Bone tissue
 Blood
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 surfaces
 Highly vascular (except cartilage)
Connective Tissue Cells
1.
“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
Once EC matrix is
○ Osteoblasts in bone
produced, “blast” cells
become “cyte” cells &
maintain the matrix
Connective Tissue Cells
2. 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 & inflammation
 Macrophages- engulf bacteria
 Plasma 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 together
 Stores water
 Provides a medium for exchange of substances
btw. cells & blood

Components:
 Fibers & Ground Substance
ECM Fibers- strengthen & support
connective tissue
Collagen
1.



strong & resist pulling forces
Not stiff thus flexible
Found in cartilage, tendons, ligaments & bone
Elastic
2.


Provides strength & stretching
Found in skin, blood vessels & lungs
Reticular
3.



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.
2.
3.
Name three cells found in connective
tissue?
What type of fiber has characteristics of
strength and flexibility?
What is ground substance? Give a
characteristic of it.
Connective Tissue Proper
 Loose
Connective Tissue- loosely
intertwined fibers btw. cells
 Areolar
 Reticular
 Adipose
 Dense
Connective Tissue- thicker, denser
fibers btw. fewer cells
 Regular
 Irregular
 Elastic
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 organs
 Binds the skin to underlying organs & fills space
between muscles
 Important 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 organs
 Surrounds capillaries
Adipose Tissue

Description
 Closely packed adipocytes
 Nucleus pushed to one side
by fat droplet

Function
 Provides reserve food fuel
 Insulates against heat loss
 Supports & protects organs

Location
 Found by areolar tissue
 Under skin- insulates the body
& protects organs
 Cushions joints
 Around 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

Description
 Parallel collagen fibers
 Fibroblasts and some elastic fibers
 Poorly vascularized

Function
 Attaches muscle to bone
 Attaches bone to bone
 Withstands great stress in
one direction

Location
 Tendons and ligaments
 Fascia 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 tissue
 Contains no blood vessels or nerves
 Matrix contains up to 80% water
 Mainly collagen & elastic fibers
 Cell type – chondrocyte

Types:
 Hyaline
 Fibrocartilage
 Elastic
Hyaline Cartilage

Description
 Collagen fibers not in the matrix (hyaline =
glassy)
 Chodroblasts produce matrix
 Chondrocytes lie in lacunae (space in mature
cartilage)

Function
 Supports and reinforces
 Resilient cushion/ Resists repetitive stress
 Reduces friction
Hyaline Cartilage

Location
 Fetal skeleton
 Ends of long bones
 Costal cartilage of ribs
 Cartilages of nose tip,
trachea, and larynx
 Joints
*weakest of the 3 cartilages
Fibrocartilage

Description
 Matrix similar, but less firm
than hyaline cartilage
 Thick collagen fibers
predominate in matrix w/
scattered chondrocytes

Function
 Tensile strength w/ ability
to absorb compressive
shock

Location
 Intervertebral discs
 Pubic 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
structure
 Allows great flexibility

Location
 Supports external ear
 Epiglottis
Bone Tissue

Function
 Supports and protects





organs
Provides levers and
attachment site for muscles
Stores calcium and other
minerals
Stores fat
Marrow 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

Function
 transport 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 tissue
 Cardiac muscle tissue
 Smooth muscle tissue
Skeletal Muscle Tissue

Characteristics
 Long, cylindrical cells
 Multinucleate
 Obvious striations

Function
 Voluntary movement
 Manipulation of
environment
 Facial expression

Location
 Skeletal 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

Characteristics
 Branching cells
 Uninucleate
 Intercalated discs

Location
 Occurs 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 with
central 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

Location
 Brain, 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 response
 Limits damage to injury site

Immune response – takes longer to
develop and very specific
 Destroys particular microorganisms at site of
infection
The Tissues Throughout Life

At the end of second month of development:
 Primary tissue types have appeared
 Major organs are in place

Adulthood
 Only a few tissues regenerate
 Many tissues still retain populations of stem cells
○ Stem cells- divide/ differentiate into specialized cell types

With increasing age:
 Epithelia thin
 Collagen decreases
 Bones, muscles, and nervous tissue begin to atrophy
 Poor 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 body
 An 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