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Chapter 5
Tissues
Tissue
• Group of similar cells that perform a common
function
• Surrounded by or embedded in a nonliving
intercellular material called a matrix
• Intercellular = “between-the-cells”
• Some tissue contains almost no intercellular
matrix, while some are almost entirely matrix
• Some tissue matrix contains fibers making them
flexible or elastic
• Some contain mineral crystals, making them
rigid
• Some are very fluid
Tissue
• Intercellular junctions such as
desmosomes and tight junctions hold
groups of cells together to form tissues
• Some matrix also holds tissue together
such as the fibers and crystals of bone
tissue
• The study of tissue is
• Histology
Tissue Types
• Epithelial
–Covers and protects body surface
–Lines body cavities
–Specializes in moving substances
into and out of blood
–Forms many glands
Tissue Types
• Connective
– Support the body and its
parts, connects and holds
together
– Transport substances
and protect from foreign
invaders
– Relatively far apart and
separated by nonliving
matrix
• Muscle
Tissue Type
– Produces movement
– Moves body and its parts
– Specialized for contractility
– Produces movement by shortening of
contractile units found in cytoplasm
• Nervous
Tissue Type
– Most complex
– Specializes in communication between
various parts of the body
– Generation of complex messages for
the coordination of body functions
Embryonic Development of Tissue
Primary Germ Layers
• Single cell zygote is converted into a
hallow ball of cells called a blastocyst
• Process in which blastocyst cells move
and differentiate into primary germ layers
is called gastrulation.
• The process in which primary germ layers
differentiate into different types of tissue is
called histogenesis
Review
• Name 4 basic types of tissue
• Give major function of each
• What are the primary germ layers?
Epithelial Tissue
Epithelial Tissue
• Contains no blood vessels (avascular)
• Oxygen and nutrients diffuse from
capillaries in underlining connective tissue
• The cells are held together by
desmosomes and tight junctions
• The cells can reproduce themselves
• Epithelial tissue is sub-divided into
membranous and glandular.
Types and Locations
• Membranous epithelium covers body parts
and lines
– serous cavities, (pleural, pericardium, and
peritoneal)
– Blood and lymphatic vessels
– Respiratory, digestive and genitourinary tracts
• Glandular epithelium form secretory units
of the endocrine and exocrine glands
Functions
•
•
•
•
•
Protection
Sensory functions
Secretion
Absorption
Excretion
Basement Membrane
• Epithelium attaches to a an underlying layer of
connective tissue by means of a thin, noncellular
layer of adhesive, permeable material called
basement membrane.
• It is made up of glycoprotein material secreted
by epithelial components (basal lamina) and a
mesh of fiber produced by connective tissue
(reticular lamina)
Classification Based on Cell Shape
• Four cell shapes
– Squamous: flat, platelike
– Cuboidal: cube shaped
– Columnar: higher than they are
wide. Narrow and cylindrical
– Pseudostratified columnar: one
layer of oddly shaped
columnar cells
Classification Based on Layers of
Cells
• Simple Epithelium: one layer
• Stratified Epithelium: layer on top
of layer
• Transitional Epithelium: differing
cell shapes layered on each other
Simple Epithelium
Simple Epithelium
Simple squamous epithelium
• Consist of one layer of flat, scalelike
cells
• Substances can readily diffuse or
filter through this tissue
• Found in alveoli of the lungs, lining
of blood and lymphatic vessels
(endothelium) and on the surfaces
of the pleura, pericardium and
peritoneum (mesothelium)
Simple Epithelium
Simple cuboidal epithelium
• One layer of cubed cells, resting on a basement
membrane
• Seen in many glands and their ducts
• Also found in kidney ducts and tubules
Simple Epithelium
Simple columnar epithelium
• Single layer of column-like
cells
• Composes the surface of the
mucous membrane that lines
the stomach, intestine,
uterus, uterine tubs and
parts of the respiratory tract.
• Some cells have
modifications (goblet, cilia
and microvilli cells)
Simple Epithelium
Simple columnar epithelium
(modifications)
• Goblet Cells
– Have large secretory vesicles
which give it a goblet appearance.
– Vesicles contain mucous (solution
of water, electrolytes, and
glycoproteins)
Simple Epithelium
Simple columnar epithelium (modifications)
• Microvilli
– Microscopic fingerlike projections
– Found in the intestines
Simple Epithelium
•
•
•
•
•
Pseudostratified columnar epithelium
Gives false impression of stratification
Cells are of various heights and only single layer
touches basement membrane
Nuclei are placed at odd and irregular levels in
the cell
Found in the lining of air passages in respiratory
system and in the male urethra
Mucous producing goblet cells and cilia is also
found this traps dust that can be moved away
from the lungs
Stratified Epithelium
Stratified Epithelium
•
•
•
•
Stratified squamous epithelium
Some contains keratin
Multi-layered flattened squamous cells
Found in skin (found in skin)
Epithelium found in the lining of vagina,
mouth and esophagus does not contain
keratin
Stratified Epithelium
Stratified cuboidal epithelium
• Two or more layers of cuboidal cells
arranged over basement membrane
• Located in sweat gland ducts, in pharynx
and over parts of the epiglottis
Stratified Epithelium
Stratified columnar epithelium
• Multi layers of columnar cells
• Found in many places such as the male
urethra, and anal mucous layer
Stratified Epithelium
Stratified transitional epithelium
• Two or more layers of varying cell shapes
• Found in areas of high stress and tension
such as the urinary bladder
• In many incidents 10 or more layers can
be observed in an un-stretched area
Glandular Epithelium
Glandular Epithelium
• Specialized for secretory activity
• May function singly as unicellular
gland or in cluster as multicellular
glands
• All glands are classified as exocrine
or endocrine glands
• Exocrine discharge secretion into
ducts such as salivary glands
• Endocrine are ductless and
discharge directly into blood or
interstitial fluid such as pituitary
gland
Structural Classification of Exocrine
Glands
• Classified by structure P133
• Shapes include tubular and alveolar
• Simple exocrine glands have only one
duct leading to the surface
• Compound have two or more ducts
Functional Classification of
Exocrine Glands
• Differ in methods of how secretions are
discharged
• 3 types
– Aprocrine
– Holocrine
– Merocrine
Functional Classification of
Exocrine Glands
•
•
•
•
•
•
APOCRINE
Collect secretory products near
apex or tip of cell
Releases into duct by pinching off
distended end
Results in some loss of cytoplasm
and damage to cell
Recovery and repair of cells are
rapid
Continued secretions occur
Located in milk producing mammary
glands
Functional Classification of
Exocrine Glands
•
•
•
•
HOLOCRINE
Collect secretory product inside
cell
Cell ruptures completely to
release secretion
Self destruct to complete
function
Found in sebaceous glands
that produce oil to lubricate the
skin
Functional Classification of
Exocrine Glands
MEROCRINE
• Discharge secretions directly
through the cell or plasma
membrane
• Completed without injury to
cell or loss of cytoplasm
• Salivary glands are one
example
Review
• List 3 functions of epithelial tissue.
• What are 3 basic shapes of epithelial
tissue?
• What is the difference between simple and
stratified?
• What are 3 exocrine glands?
• How do they secrete their products?
Connective Tissue
Connective Tissue
• Most wide spread tissue in the body
• Connects, supports, transports and
defends
• Exists as
– Delicate tissue-paper webs
– Rough resilient cords
– Rigid bones
– Fluid
Connective Tissue
• Consists mostly of intracellular material
called matrix
• Embedded in the matrix are varying kinds
of fibers, fluid and other substances known
as ground substance
• Quality of matrix determine the structural
characteristics of connective tissue.
– Example: the matrix of blood is fluid (plasma).
It contains numerous blood cells but no fibers
Connective Tissue
• Most contain one or more types of fibers
– Collagenous
• Tough
• White fibers
• Made of collagen
• Occur in bundles
• Most Abundant, constitutes somewhat over
¼ of all protein in the body
• One of the most basic factors in the aging
process
Connective Tissue
– Reticular
• Delicate
• Made of specialized type of collagen called
reticulin
• Occur in networks
• Support structures such as capillaries and nerve
fibers
– Elastic
• Made of protein called elastin
• Found in stretchy tissue such as cartilage of
external ear
Classification of Connective Tissue
• Fibrous
–
–
–
–
Loose, ordinary (areolar)
Adipose
Reticular
Dense
• Bone
• Cartilage
– Hyaline
– fibrocartilage
– elastic
• Blood
• See Table 5-3 P135
Fibrous Connective
Tissue
Loose Connective Tissue (Areolar)
• Areolar means “like a small space”
• Loose because it is stretchable
• Ordinary because it is the most widely
distributed
• Connects many adjacent structures (the
elastic glue)
• Matrix is soft viscous gel due to hyaluronic
acid
Loose Connective Tissue (Areolar)
• The enzyme hyaluronase can change
matrix from gel to a watery consistency
• This has been used medically to lesson
pain and hasten absorption of mixed in
drugs
• Bacteria such as pneumococci and
strpetococci use to spread through
connective tissue
Loose Connective Tissue (Areolar)
• Contains numerous fibers and cells.
(usually fibers are collagenous and elastic
fibers)
• Fibroblast are the greatest number of cells
• These cells synthesize the gel-like ground
substance along with the fibers in it
• Macrophages second
Adipose Tissue
• Contains mostly fat cells.
• Fewer fibroblast and macrophages than
areolar tissue
• Forms supporting, protective pads around
kidney and other structures
• Storage depot for excess food
• Acts as insulting material to conserve body
heat
• See figure 5-15 page 138 for locations
Reticular Tissue
• 3D web or network
• Slender branching reticular fibers with
overlaying reticular cells
• Forms framework of spleen, lymph, nodes
and bone marrow
• Functions as mechanism for defending
against microorganisms and injurious
substances
Reticular Tissue
• Filters injurious substances out of the
blood and lymph
• These substances are then phagocytosed
by reticular cells
• Reticular cells also make reticular fibers
Dense Fibrous Tissue
• Consist of fibers packed densely in the
matrix
• Relatively few fibroblast cells
• Designated regular and irregular
• Regular:
– tissue bundles arranged in parallel rows
– Mostly bundles of collagen fibers
– Flexible but still has great tensile strength
(tendons)
Dense Fibrous Tissue
• Irregular
– Mostly bundles of elastic fibers
– Not arranged in parallel rows
– Strong inner skin layer (dermis)
– Outer capsule of kidney and spleen
Dermis
Tendon
Bone Tissue
•
•
•
•
•
•
Bone
Osseous tissue
Highly specialized
65% is inorganic material (bone sat)
Bones provide support and protection
Points of muscle attachment
Serve as mineral reservoir for body
• Osteocytes:
Bone
– Mature bone cells
• Osteon (Haversian system):
– Fundamental functional unit of much
compact bone.
• Lacunae:
Bone
– small spaces
• Lamellae
– Concentric layers of compact bone tissue
– Forms a series of tubes around narrow channels
(Haversian canal)
• Canaliculi
– Network of small canals
– Connect lucunae and osteocytes with nutrient blood
vessels found in Haversian canal
• Osteoblasts:
Bone
– Bone forming cells
– Form new bone
• Osteoclasts
– Bone destroying cell
• Membrane bones
– bone that forms directly in membranous connective
tissue, as some cranial bones
• Endochondral ossification
– replacement of cartilage by bone
– bone formation found in the development of long
bones such as the femur and humerus.
Cartilage
Cartilage
• Has one cell type: chondrocyte
• Chondrocyte produces tough, gristle-like
substances and the fibers
• Found in small openings (lucunae)
• Avascular
• Injuries heal slowly and sometimes not at all
• Nutrients delivered by diffusion
– Blood vessels located in specialized tissue membrane
called perichondrium
– Inefficient method
Cartilage
• Hyaline cartilage
– Appearance is shiny and translucent
– Most prevalent type
– Found in support rings of respiratory tubes
– Covers the end of bones that articulate at
joints
Cartilage
• Fibrocartilage
– Strongest and most durable type
– Matrix is filled with strong white fibers
– Disc serve as shock absorbers in vertebrae
and in knee joint
– Damage occurs frequently in knee
fibrocartilage as a result sports related injuries
Cartilage
• Elastic cartilage
– Contains lots of very fine elastic fibers
– Fibers give extra strength and flexibility
– Found in external ear and larynx
Blood
Blood/Hemapoietic Tissue
• Divided into liquid fraction and formed
elements
• Liquid fraction called Plasma
(55% of whole blood)
• Formed elements are called Blood cells
(45% of whole blood)
– Erythrocytes (Red Blood Cells)
– Leukocytes (White Blood Cells)
– Thrombocytes (Platelets)
Blood/Hemapoietic Tissue
• Transports respiratory gases, nutrients and
waste products
• Helps maintains constant body temperature
• Helps regulate body fluid pH.
• WBC function in destroying harmful
microorganisms
• Formed in red bone marrow
• Hematopoiesis: Process of differentiation that
form blood tissue
Inflammation/
Inflammatory
Response
Inflammation/Inflammatory
Response
• Complex way cells and tissue react to injury
• Sequence of events that occur as a results of
injury, disease, etc
• Things such as bacteria, viruses, physical injury,
disease, chemicals, etc can trigger the
inflammatory response
• 1st centaury AD Roman physician Celsus
established the 4 signs
–
–
–
–
Rubor (redness)
Calor (heat)
Tumor (swelling)
Dolor (pain)
Inflammation/Inflammatory Response
1. Injury
2. Blood vessel constrict
3. Then immediately
dilate
4. Chemicals released by
injured tissue including
histamine, serotonins
and kinins
Inflammation/Inflammatory Response
4. Increased Vasodilation
Blood components leak
out into tissue spaces
5. White cells begin to
accumulate in vessel
near the point of injury
(margination of
leukocytes)
6. Build-up of dead
leukocytes and tissue
debris cause pus
Inflammation/Inflammatory Response
7. Bacteria and cell debris
is eaten away by
phagocytes
8. Tissue heals
Review
• Name 3 types of fibers that may be
present in connective tissue
• Name 3 types of fibrous connective tissue
• Describe each
• What makes bone tissue hard?
Muscle Tissue
Muscle Tissue
• Three types
– Skeletal muscle tissue
(striated voluntary muscle tissue)
– Smooth muscle tissue
(Visceral muscle tissue) (nonstriated involuntary
muscle tissue)
– Cardiac muscle tissue
(striated involuntary muscle tissue)
Skeletal
Smooth
Cardiac
Nervous
Tissue
Nervous Tissue
• Rapidly regulates and integrates the
activity of different parts of the body
• Organs of nervous system are the brain,
spinal cords and nerves
• Ectodermal in origin and has two basic
kinds of cells
– Neurons (nerve tissue)
– Neuroglia (special connecting and supporting
cells)
Neurons
Review
•
•
•
•
Name 2 types of involuntary muscle
Where are they found?
Name 2 types of cells in nervous tissue.
What are their functions?
Tissue Repair
Tissue Repair
• Tissue can repair when damaged
• Phagocytic cells remove dead or injured
cells
• New tissue then forms and fills in gap
(regeneration)
• Epithelial and connective tissue have the
greatest capacity to regenerate
– Cells quickly divide and fill the wound
– Usually with fibrous tissue that may be
replaced by normal tissue later, if tissue is
small
http://www.youtube.com/watch?v=fAOti396K_4&feature=related
Tissue Repair
• If fibrous tissue mass is deep or large it may
remain as dense fibrous tissue mass called a
scar
• An unusually thick scar that develops in the
lower layer of skin is called a Keloid
• Muscle tissue has limited capacity to regenerate
– Damaged muscle is often replaced with fibrous
connective tissue instead of muscle
– Organ involved can lose some or all of its functions
Tissue Repair
• Nerve tissue has limited capacity to
regenerate or in cases of brain and spinal
cord, do not regenerate at all.
– Neurons outside brain and spinal cord can
sometimes regenerate but extremely slowly
and only if certain neuroglia are present
– Discovery of nerve growth factors produced
by neuroglia offers promise of treating brain
tissue damage
Body Membranes
Body Membranes
• Thin sheet like structure that covers and protects
body surfaces
• Lines body cavities
• Covers inner surface of hollow organs
• Some anchor organs to other organs or bones
• In certain areas they secrete lubricating fluids to
decrease friction
• 2 major categories
– Epithelial membranes
– Connective tissue membrane
Epithelial membranes
• Composed of epithelial tissue and
underlying layer of specialized connective
tissue
• 3 types
– Cutaneous membrane
• Covers body surface exposed to
external environment (skin)
• Composes the largest visible organ in
the body
• 16% of body weight
Epithelial membranes
– Serous membranes
• Secrete thin, watery fluid that
lubricates organs
• Lines body cavities not opened to
external environment
• Covers organs in those cavities
• Parietal membrane
covers cavity wall
• Visceral membrane
covers organ surfaces
Epithelial membranes
• Serous membranes
• Pleura
surrounds lungs and lines thoracic cavity
• Peritoneum
lines abdominal organs and cavity
• Pericardium
surrounds the heart
• Composed of two distinct layers
–Thin layer simple squamous epithelium
(epithelial sheet)
–Connective tissue layer
Epithelial membranes
– Mucous membrane
• Line body surfaces opening directly to
exterior (respiratory, digestive, urinary
and reproductive tracts)
• Produce film of mucous that coats and
protects underlying cells
• Lubricates food in digestive tract
• Serves as sticky trap for contaminates
in respiratory tract
Connective Tissue membranes
– Connective Tissue Membranes
• Do not contain epithelial components
• Lines spaces between bone and joints that
move (synovial membranes)
• Smooth and slick, secrete thick , colorless,
lubricating fluid (synovial fluid)
• Reduce friction between bone and joint.
• Line small cushion-like sacs found between
some moving body parts. (bursae)
Mechanisms of Disease
• Neoplasm is a tumor
• Neoplasm can be classified as malignant
or benign
• When malignant tumors or cancer migrate
by way of lymphatic system or blood
vessels this is known as metastasis
• Three types of tumors: Epithelial,
connective and misc
Benign Epithelial Tumors
•
Papilloma
Adenoma
Nevus
Malignant Epithelial Tumors
Carcinomas
Melanoma
Adenocarcinoma
Benign Connective Tumors
Lipoma
adipose
tumor
Osteoma
bone tumor
Chondroma
Cartilage Tumor
Malignant Connective Tumors
Sarcomas
Lymphoma
Osteosarcoma
Fibrosarcoma
Causes of Cancer
• Hyperplasia
– Uncontrolled cell division (too many cells)
• Anaplasia
– Abnormal undifferentiated cells
Basically cancer is a mistake or problem in cell
division. The cause is uncertain but several
factors could play a key role
Factors Involved in the Role of
Cancer Production
• Genetic factors
– Can be inherited
• Oncogen or cancer causing gene
• Mutated tumor suppressor gene (does not work
properly)
• Breast, skin and nerve tissue cancers
• Carcinogens
– Cancer causing agents in the environment
• Mutagens cause mutations in DNA structure
• Radiation
• Viruses (papilloma virus)
• Age
Detection of Cancer
• Cancer specialist
– oncologist
• Early detection is important
– Self-exam
– Medical imaging (mammography, MRI, CT,
ultrasounds)
– Blood test
– biopsy
• Appearance of abnormal, rapidly growing
tissue
Cancer Treatments
• Stage: Size of cancer
• Grade: what cancer is likely to do based on
degree of abnormality of cells
• No treatment usually results in death
• Surgical removal
• Chemotherapy
– Cytotoxic (cell-killing) and/or antineoplastic drugs
• Radiation therapy
– Xray and gamma radiation
• Laser therapy
• Immunotherapy
– Uses bodies own defenses against cancer (such as
with vaccines)