Download Animal Tissues

Animal Tissues
Introduction
Animal bodies are organized into hierarchical
levels with each level built from the level below it
– cells – the smallest units of the body that are alive
and all living things are composed of cells
– tissues – group of like cells working together to
perform the same function
– organ – a group of several different types of tissues
working together to perform a specific function
– system – a group of organs working together to
perform a very complex, integrated process
– organisms – all the systems working together to
sustain life
1. While cells are basic functional and
structural unit of life, they function in
groups as tissues to carry out specialized
activities
2. Properties of tissues are influenced by
factors such as extracellular material and
connections between cells
3. Tissues may be hard, semisolid, or liquid
4. Vary with kind of cells present, cellular
arrangement, and types of fibers present
AnimalTissues
Classified into four groups according to
– function
– structure
Groups
1. epithelial
2. connective
3. muscle
4. nervous
Body Tissues Classification
1. Epithelial Tissue
•
covers body surfaces, lines hollow organs,
cavities, and ducts, and forms glands
2. Connective Tissue
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protects and supports body and organs
binds organs together
stores energy reserves as fat
helps provide immunity
Body Tissues Classification
3. Muscular Tissue
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generates physical force
4. Nervous Tissue
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monitors and responds to changes in a
variety of conditions inside and outside the
body
helps maintain homeostasis
Epithelial Tissues
General Features
Epithelium (singular) or epithelia (plural)
• lines body surfaces
• cells closely packed
– tightly held together with numerous junctions
•
cells arranged in sheets
– single layers = simple
– multiple layers = stratified
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surfaces
– apical = free surface or superficial layer
– basal = attached to basement membrane or
deepest layer
Figure 4.1
Epithelial Tissue
basement membrane
• thin extracellular layer made up of
– basal lamina
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closest to epithelial cells
secreted by epithelial cells
components
– collagen, laminin, and glycoproteins
– reticular lamina
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deep to basal lamina
part of connective tissue layer
produced by fibroblasts
Epithelial Tissue
Basement membrane functions
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attach and support epithelium
migration surface for growth and repair
filter large molecules and cells
Epithelium characteristics
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avascular
high rate of cell division
– because apical surface cells sloughed off,
worn off, and damaged then replaced
– two types
1. covering and lining
2. glandular
Figure 4.2
Covering and Lining Epithelia
Classified according to
1. arrangement of cells in layers
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simple = single
stratified = multiple
pseudostratified = single but appears multiple
2. cell shapes
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squamous = flat apical surface
cuboidal = shaped like cubes or hexagons
columnar = taller than wide, apical surface
may have cilia or microvilli
transitional = change shape from cuboidal to
flat and back allowing stretch and recoil
Table 4.1 pt 1
Table 4.1 pt 2
Table 4.1 pt 3
Table 4.1 pt 4
Table 4.1 pt 5
Table 4.1 pt 6
Table 4.1 pt 7
Glandular Epithelia
Glandular cell function is secretion
• often lie in clusters deep to covering and
lining epithelium
• consist of single or multiple cells
Classification of glands
• exocrine
– into ducts
– onto a surface
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endocrine
– into the blood
Table 4.1 pt 8
Table 4.1 pt 9
Connective Tissues
Connective Tissue
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Most abundant tissue type
Functions
1. binds together, supports, strengthens other
tissue types
2. protects and insulates internal organs
3. compartmentalizes structures
4. major transport system
5. major site of stored energy reserves
6. main site of immune responses
General Features
Two basic elements
1. cells
2. extracellular matrix
Characteristics
1. do not occur on surfaces
2. usually highly vascular
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exceptions include cartilage and tendons
3. have nerve supply
Types of Cells
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Major types of connective tissues have
immature “blast” cells
– fibroblasts in loose and dense connective
– chondrobasts in cartilage
– osteoblasts in bone
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Blast cell characteristics
– mitotic
– secret matrix
– differentiate into “-cyte” cells
Types of Cells
1.
2.
3.
4.
5.
fibroblasts
macrophages
mast cells
adipocytes
white blood cells (WBC)
Figure 4.3
Extracellular Matrix
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determines classification of connective
tissues
two components
– ground substance
– fibers
Ground Substance
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between cells and fibers
can be fluid, semifluid, or calcified
functions
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supports cells
binds cells together
stores water
provides medium for substance exchange
active in tissue development, migration,
proliferation, shape and metabolic functions
Ground Substance
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contains large organic molecules
complex combinations of
polysaccharides and proteins
– glycosaminoglycans or GAGs
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trap water
example: hyaluronic acid
Fibers
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Function to strengthen and support
Three major types
1. collagen
2. elastic
3. reticular
Collagen Fibers
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very strong
resist pulling forces
not stiff
often occur in parallel bundles
most abundant protein in body 25% of
total proteins
found in most connective tissue types
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bone
cartilage
tendons
ligaments
Figure 4.3
Elastic Fibers
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smaller in diameter than collagen
branch and join together forming network
protein named elastin
can stretch up to 150% of relaxed length
without breaking
ability to return to original shape
plentiful in
– skin
– blood vessel walls
– lung tissue
Reticular Fibers
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collagen arranged in fine bundles
coated with glycoprotein
provide support in walls of blood vessels
help form the basement membrane
form network around cells of some
tissues
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areolar
adipose
smooth muscle
plentiful in reticular connective tissue
Connective Tissue Types
Two basic groups
• embryonic connective tissue
• mature connective tissue
1.
2.
3.
4.
5.
loose
dense
cartilage
bone
liquid
Mature Connective Tissue
1. loose
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areolar connective tissue
adipose tissue
reticular connective tissue
2. dense
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dense regular
dense irregular
elastic connective
3. cartilage
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hyaline
fibrocartilage
elastic cartilage
4. bone
5. liquid
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blood
Figure 4.4
Table 4.2a
Table 4.2b
Table 4.2c
Table 4.2d
Table 4.2e
Table 4.2f
Table 4.2g
Table 4.2h
Table 4.2i
Table 4.2j
Table 4.2k
Muscular Tissues
Muscular Tissue
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generates physical force needed to make
body structures move
produces movement
maintains posture
generates heat
three types
1. skeletal
2. cardiac
3. smooth
Skeletal Muscle
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striated
long cells (up to 30-40cm)
cylindrical in shape
many nuclei at periphery of cell
fibers are parallel
voluntary
Cardiac Muscle
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striated
branched
single nucleus at center of cell
– sometimes two nuclei
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intercalated discs
– cell junctions
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strengthen tissue and hold cells together
provide route for quick conduction of impulses
involuntary
Smooth Muscle
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nonstriated
unbranched
small
spindle shaped (thick middle, tapered ends)
single nucleus at center of cell
involuntary
Table 4.3 pt 1
Table 4.3 pt 2
Table 4.3 pt 3
Nervous Tissues
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Nervous Tissue
two principal types of cells
1. neurons
– sensitive to various stimuli
– convert stimuli into impulses
– conduct impulses to:
1. other neurons
2. muscular tissue
3. glands
– parts of a cell
1. cell body
2. dendrites
3. axon
2. neuroglia
– smaller than neurons
– support, nourish, protect neurons
Table 4.4
Tissue Repair
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Tissue Repair
ability to repair depends on
– extent of damage
– tissue type
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epithelium
– continuous capacity for renewal
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connective
– some have continuous capacity for renewal
– others replenish less readily because of smaller
blood supply
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muscle
– relatively poor capacity for renewal
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nervous
– poorest capacity for renewal
Tissue Repair
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New cells originate by cell division from
– parenchyma (functioning part of tissue)
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repair will be near-perfect reconstruction
– stroma (supporting connective tissue)
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repair will include new connective tissue and scar
formation will occur
original function of tissue or organ is impaired
tissue repair affected by
– nutrition
– blood circulation