Chapter 2:
The Cell
Chapter 4: Tissues
• Tissues – “to weave”
– Cells that are organized into layers or groups
whose size, shape, arrangement and function
are similar.
• 4 Major Types
– Epithelial (covering)
– Connective (support)
– Muscle (movement)
– Nerve (control)
Epithelium Tissue
•
•
Covers all inner and
outer body surfaces
Characteristics
– Rapidly growing,
regenerative
– Avascular
– Secretions (glands)
– Absorption (gut)
– Excretion (gut)
– Filtering (kidney)
– Sensory (innervated)
Classification of Epithelia
• Simple
– single layer
• Stratified
– More than one layer
• Squamous
– “plate like”, wider than
tall
• Cuboidal
– Cubes, about as wide
as tall
• Columnar
– Taller than wide
Epithelial Tissues
Draw
•
•
•
•
•
•
Simple squamos
Simple cubodial
Simple columnar
Pseudostratified columnar
Stratified squamos
Transitional
Mesothelium; Meso = middle, lining of body cavities
Endothelium; Endo = inner, lining blood and lymph vessels, heart lining
Chapter 4: Tissues
• Tissues – “to weave”
– Cells that are organized into layers or groups
whose size, shape, arrangement and function
are similar.
• 4 Major Types
– Epithelial (covering) 3
– Connective (support)
– Muscle (movement)
– Nerve (control)
Connective Tissue
• 4 main classes of connective tissue:
–
–
–
–
Connective tissue proper
Cartilage
Bone
Blood
• Functions?
– Form basis of the skeleton (bone and cartilage)
– Store and carry nutrients (fat tissue and blood)
– Connective tissue proper
– Helps fight infection
Four Main Classes of Connective Tissue
• Loose aggregation of
cells, fibers and by
nonliving extracellular
material called the
extracellular matrix.
• Various C.T. is due to
differences in the
extracellular matrix.
• Loose aggregation of
cells, fibers and by
nonliving extracellular
material called the
extracellular matrix.
• Various C.T. is due to
differences in the
extracellular matrix.
Prototype connetive tissue: loose areolar.
Ground Substance
• The viscous, spongy part of the extracellular matrix of C.T.,
large molecules attract water and tissue fluid.
• Fluid, nutrient and waste content varies with proximity of
capillaries and density of C.T. type.
– e.g. fibroblasts secrete sugar and protein molecules
• It can also contain
macrophages, mast cells,
plasma cells, neutrophils,
eosinophils.
Fibers
• Produced by fibroblasts and chondroblasts.
• Function: Provide support
• 3 types
– Collagen
– Reticular
– Elastic
Collagen
• Strongest and most abundant
in areolar tissue, which
withstands tension.
• Only slightly elastic
• Cross linked at molecular level
giving great tensile strength.
• Vitamin C responsible for
crosslinking fibers.
– VitC-Scurvy-C.T.
• Whitish in color
Reticular
•
•
•
Reticulum = network/netted
Bundles of a special type of collagen unit fibril.
Thin and short fiber that is highly branched forming
support networks.
• Found in lymph
nodes, spleen, liver
and capillaries.
• More flexible than
collagen fibers.
Elastic
• Long and thin fibers that branch to form wide
networks within the extacellular matrix.
• Elastic properties are due to rubberlike protein called
elastin.
• These fibers “recoil”
after collagen limit is
met and brings cell
back into shape.
Connective Tissue Proper
• Forms supporting network of many
organs.
• Characterized by ground substance and
reinforcement fibers.
• There are 2 subclasses:
– loose connective tissue and
– dense connective tissue
Loose Connective Tissue
(3 types)
• Areolar (loose)
– Almost all tissues either border or are embedded by areolar C.T.
due to nutrient diversity.
– Function: Binds skin to underlying muscles, surrounds muscle
groups, nerves and blood vessels.
– Also functions as support, holds fluid, fights infection, storage.
• Adipose (fat)
– Adipocytes store fat droplets (yellow in color)
– Acts as a cushion and heat insulator
– Found around heart, kidney, breast, abdomen, bone marrow,
skin hypodermins.
• Reticular
– Thin fiber network functioning to support tissue in liver, spleen,
lymph node, and bone marrow.
C.T. Proper: Loose Connective Tissue, Areolar
C.T. Proper: Loose Connective Tissue, Adipose
C.T. Proper: Loose Connective Tissue, Reticular
Dense Connective Tissue
• Fibrous C.T. which contains more collagen
so is extremely strong.
Dense Connective Tissue
• Irregular
– Thick collagen fibers running in many directions allowing
resistance in many planes
– Found in leathery dermis, fibrous capsule of kidney, lymph, joints
and GI submucosa.
• Regular “white fibrous”
– Dense, parallel collagen fibers, usually parallel to direction of
force
– Little ground substance
– Found in tendons, ligaments, aponeuroses.
• Elastic C.T.
– Dominated by thick, parallel elastic fibers = strength + elasticity
– Found in vocal cords, ligaments between adjacent vertebrae.
C.T. Proper: Dense Connective Tissue, Irregular
C.T. Proper: Dense Connective Tissue, Regular
Other Connective Tissue
• Cartilage (3 types: hyaline, elastic, fibrocartilage)
– Rigid C.T. which provides shape and support,
cushioning, smooth movement, high water content
– Lacks blood supply and innervation
– Source: chondrocytes that lie in lacunae
• Bone (osseous tissue)
– Calcified matrix with collagen fibers. Hardness of
bone is due to mineralization
• Blood
– Red and white cells, platelets in fluid matrix (plasma)
Other Connective Tissue: Cartilage, Hyaline
Most common type of cartilage tissue, ‘milky glass’ appearance, gristle.
Embryonic skeleton. Fine collagen fibers imperceptible. Found in
articular surfaces, tracheal rings, etc.
Other Connective Tissue: Cartilage, Elastic
Similar to hyaline with flexible and elastic fibers in matrix forming
external framework.
Other Connective Tissue: Cartilage, Fibrocartilage
Very tough fibrous tissue
Other Connective Tissue: Bone
Other Connective Tissue: Blood
Composite Tissues
• A composite tissue is muscle or nerve tissue
plus areolar tissue.
• Muscle Tissue
– Contractile tissue with elongated muscle fibers with
areolar C.T. Rich blood supply.
– Function: body movement and bracing
•
•
•
Skeletal (striated or voluntary)
Cardiac
Smooth (involuntary)
Skeletal Muscle
Action is to pull on bones. Appears striated due to arrangements
of myofilaments. a.k.a. striated or voluntary muscle;
Cardiac Muscle
Smooth Muscle
Cannot be consciously stimulated to contract (involuntary muscle).
Found in GI tract, artery walls, bronchioles, uterus. Squeezes tubes.
Nervous Tissue
• Nervous Tissue
– Brain, spinal cord, peripheral nervous system
• Neuron (nerve cell)
– Transport nerve impulses along cytoplasmic extensions
to other neurons, muscles, glands, etc.
– No regeneration after development but some repair is
possible.
• Supporting cells (neuroglia)
– Nonconducting cells that nourish, support and bind, and
insulate nervous tissue.
Neurons