Tissues II
Ch. 4
Connective Tissue
Matrix
• Extracellular substances in which connective
tissue cells are imbedded.
– Support, strength, elasticity
• Hyaluronic acid: lubricates joints, maintains
shape (eyeball)
• Chondroitin sulfate: support, adhesion of
cartilage, bone, heart valves, cornea, umbilical
cord
Matrix
• Collagen fibers: cartilage, tendons, ligaments
(inelastic)
• Reticular fibers: support fat, nerves, muscle,
and blood vessels (collagen, glycoproteins)
• Elastic fibers: elastin protein, skin and blood
vessels
Connective Tissue (CT)
• 4 classes of connective tissue
1.
2.
3.
4.
Connective Tissue Proper
Cartilage
Bone
Blood
Most abundant and
widely distributed of the
4 tissue types in body,
amount in particular
organs varies
Functions of Connective Tissue
1. Binding and support
Ex. bone, connective tissue proper
2. Protection
Ex. bone, connective tissue proper
3. Insulation
Ex. connective tissue proper
4. Transportation
Ex. blood
5. Stores energy
Ex. Connective tissue proper
Characteristics of Connective Tissue
• All connective tissues arise
from mesenchyme
• Cells widely scattered
within extracellular matrix
(except adipose tissue)
• Most of CT is non-living
extracellular matrix
• Most highly vascularized
(except cartilage)
Extracellular Matrix of Connective Tissue
• Consists of
A. Ground substance material in space around
cells; largely consists of
proteins & fluid
B. Fibers
1.
2.
3.
Collagen fibers - Made of
collagen (a fibrous
protein), most
abundant/strongest
Elastic fibers - Made of
elastin (a rubber-like
protein) thin, branching
Reticular fibers - Made of
collagen, thin branching
Connective Tissue Cell Types
1. Macrophages –
“eat” foreign
molecules
1. Fibroblast –
secrete fibers until
they mature into
fibrocytes
1. Leukocytes (WBC)–
immune response
4. Mast cells –
inflammatory
response
5. Adipocyte – fat cell
• Cells maturity has different names
– blast means forming => these are immature, actively
mitotic cells that secrete ground substance and fibers for
that particular matrix
– cyte indicates a blast cell that has become a mature, less
active cell
Macrophages - phagocytize and break-down foreign materials
(macrophages are mature)
Leukocytes or white blood cells - involved in immune response
Mast cells- involved in inflammatory response
Adipocyte - fat cells- store nutrients
Connective Tissue (CT)
• 4 classes of connective
tissue
1. Connective Tissue
Proper
2. Cartilage
3. Bone
4. Blood
1. Connective Tissue (CT) Proper
A. Loose CT
1. Areolar Loose CT
2. Adipose Loose CT
3. Reticular Loose CT
B. Dense CT
1. Dense regular CT
2. Dense irregular CT
3. Dense elastic CT
A. Loose Connective Tissue
Other Function- soak up fluid that would cause
edema, underlies most epithelial tissue, abundant.
edema
LCT: Adipose
• Adipocytes - store fat, nucleus displaced to the side
• SUPPORTS AND PROTECTS ORGANS, STORES FAT,
INSULATES
• White fat = stores nutrients
• Brown fat = lost of mitochondria to make heat
instead of ATP
– Babies
STROMA (“MATTRESS”)- internal framework support reticular fibroblasts and others
(white blood cells, mast cells, macrophages)
B. Dense (Fibrous) Connective Tissue
DCT: Dense Regular
• Little ground substance, mainly thick wavy
collagen fibers running in parallel - very strong
and provides resistance to pulling (in the
direction the fibers run)
– few elastic fibers
• Fibroblasts are the cells - constantly making
collagen fibers
• FORM TENDONS, LIGAMENTS, AND
APONEUROSES
Dense Regular Connective Tissue
Makes up:
a. Ligaments - attach bone to
bone, more elastin
a. Tendons - attach muscle to
bone, cord-like
a. Aponeuroses – sheet-like;
attach muscle to muscle or
bone
a. Fascia - “plastic wrap” for
muscles
fibroblasts between elastic fibers, Allows tissue to recoil after stretching
-walls of large arteries, walls of bronchial tubes and lungs, ligaments attaching
vertebra together
2. Cartilage
A. Characteristics
1. Matrix – gel-like (up to
80% water)
2. Avascular
•
•
• At what developmental
stage would the
chondroblasts stop
secreting matrix?
Nutrients from blood vessels
in perichondrium
Dense irregular CT
membrane
3. Cells called chondroblasts
secrete matrix (immature),
mature into chondrocytes
(in lacunae)
4. Can withstand tension and
compression
2. Cartilage
B. Types
1. Hyaline cartilage
2. Elastic cartilage
3. Fibrocartilage
SHOCK ABSORBER
LC2
3. Bone
A. Characteristics
1. Matrix
• Calcium salts
• Collagen fibers
2. Vascularized
1. Cells called osteoblastssecrete matrix
(immature), mature
into osteocytes (1 per
lacuna)
3. Bone
B. Types
1. Compact Bone
Osteon (Haversion System) –
fundamental unit
- Lamella – (bone calcium salt
ring)
- Lacuna – space containing
the osteocyte
- Central (Haversion) Canalblood, lymph, nerves
- Volkmann’s Canal –
transverse canals
- Canaliculi – microscopic
canals between lacunae
2. Spongy Bone
– Trabeculae (thin lattice plates)
4. Blood
A. Characteristics
1. Matrix – plasma (90% water)
2. Cell types –
i.
Red blood cells (erythrocytes) – no nucleus, O2 and CO2
transport
•
ii.
White blood cells (leukocytes) - nucleated, 5 types
1.
2.
3.
4.
5.
iii.
If there is no nucleus what cellular process is not functional?
Neutrophils
Lymphocytes
Monocytes
Eosinophils
Basophils
Platelets (thrombocytes) – blood clotting
Muscle Tissue
-Contractile Tissue
3 Types:
1. Skeletal
2. Cardiac
3. Smooth
Thin and thick myofilaments give banded look, many mitochondria
Sarcolemma – plasma membrane
Sarcoplasm - cytoplasm
Involuntary, specialized gap junctions called intercalated discs
INVOLUNTARY CONTROL
Nervous Tissue
Nervous Tissue
• Cell types:
1. Nerve cell = neuron generate and transmit electrical impulses
a. Dendrites – receives and responds
b. Axon – transmits impulse
2. Supporting cells: do not conduct impulses
Stimulus
LC3
Membranes
• Made up of different tissues put together to
form a specialized function
Membranes
• 4 types
– Cutaneous – skin
• IS AN ORGAN SYSTEM!
• Outer layer is stratified squamous epithelium that is
keratinized (called epidermis) and underlying dermis
(dense irregular connective tissue)
Membranes
• 4 types
1. Cutaneous - skin
2. Serous - lining ventral body cavity and organs
1. simple squamous epithelium (called mesothelium)
and underlying layer of areolar loose connective
tissue
• 4 types
Membranes
1. Cutaneous - skin
2. Serous - lining ventral body cavity and organs
3. Mucous - line body cavities open to exterior
1. stratified squamous or simple columnar epithelia and
underlying layer of areolar loose connective tissue
Membranes
• 4 types
1.
2.
3.
4.
Cutaneous - skin
Serous - lining ventral body cavity and organs
Mucous - line body cavities open to exterior
Synovial - line joint cavities
Loose areolar connective tissue and adipose
Membranes
1. Cutaneous – ET and CT
1. Serous – ET and CT
1. Mucous – ET and CT
1. Synovial – CT and CT
LC4