Download Tissue Types

TISSUES
1
Introduction
• Similar cells with a common function are
called tissues.
• The study of tissues is called histology.
• There are four (4) primary or major tissue types:
1.
2.
3.
4.
Epithelial Tissue
Connective Tissue
Muscle Tissue
Nervous Tissue
2
Intercellular Junctions
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Tight junctions
• Close space between cells
• Located among cells that
form linings
Desmosomes
• Form “spot welds” between cells
• Located among outer skin cells
Gap junctions
• Tubular channels between cells
• Located in cardiac muscle cells
Cell membrane
Tight junction
Cell membrane
Desmosome
Cell membrane
Gap junction
3
Epithelial Tissue
• General characteristics:
• Cover organs and the body
• Line body cavities
• Line hollow organs
• Have a free surface
• Have a basement membrane
• Are avascular
• Cells readily divide
• Cells tightly packed
• Cells often have desmosomes
• Function in protection, secretion, absorption, and excretion
• Classified according to cell shape and number of cell layers
4
Epithelial Tissue
• Simple squamous:
• Simple cuboidal:
• Single layer of flat cells
• Substances pass easily through
• Line air sacs
• Line blood vessels
• Line lymphatic vessels
• Single layer of cube-shaped cells
• Line kidney tubules
• Cover ovaries
• Line ducts of some glands
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Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Free surface
of tissue
Lumen
Nucleus
Simple
squamous
epithelium
Basement
membrane
Basement
Free surface
of tissue
Nucleus
Simple
cuboidal
epithelium
Connective
tissue
Connective
tissue
(a)
(b)
b,d: © Ed Reschke
(a)
(b)
b: © The McGraw-Hill Companies, Inc./Al Telser, photographer
5
Epithelial Tissue
• Simple columnar:
• Pseudostratified columnar:
• Single layer of elongated cells
• Nuclei usually near the basement
• Membrane at same level
• Sometimes possess cilia
• Sometimes possess microvilli
• Often have goblet cells
• Line uterus, stomach, intestines
• Single layer of elongated cells
• Nuclei at two or more levels
• Appear striated
• Often have cilia
• Often have goblet cells
• Line respiratory passageways
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Cilia
(free surface
of tissue)
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Cytoplasm
Mucus
Goblet cell
Nucleus
Nucleus
Cytoplasm
Basement
membrane
Microvilli
(free surface
of tissue)
Connective
tissue
Goblet cell
(a)
(b)
Basement
membrane
b: © The McGraw-Hill Companies, Inc./Dennis Strete, photographer
Connective
tissue
(a)
(b)
6
b: © The McGraw-Hill Companies, Inc./Al Telser, photographer.
Epithelial Tissue
• Stratified squamous:
• Stratified cuboidal:
• Many cell layers
• Top cells are flat
• Can accumulate keratin
• Outer layer of skin
• Line oral cavity, vagina, and
anal canal
• 2-3 layers
• Cube-shaped cells
• Line ducts of mammary glands,
sweat glands, salivary glands, and
the pancreas
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Free surface
of tissue
Stratified
cuboidal
epithelium
Nucleus
Squamous
cells
Lumen
Free surface
of tissue
Basement
membrane
Connective
tissue
(a)
(b)
Layer of
dividing
cells
Basement
membrane
b: © The McGraw-Hill Companies, Inc./Al Telser, photographer.
Connective
tissue
(a)
(b)
b: © The McGraw-Hill Companies, Inc./Al Telser, photographer
7
Epithelial Tissue
• Transitional:
• Stratified columnar:
• Many cell layers
• Cube-shaped and elongated
cells
• Line urinary bladder,
ureters, and part of urethra
• Top layer of elongated cells
• Cube-shaped cells in deeper
layers
• Line part of male urethra and
part of pharynx
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Free surface
of tissue
Unstretched
transitional
epithelium
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Lumen
Basement
membrane
Free surface
of tissue
Stratified
columnar
epithelium
(a)
Underlying
connective tissue
(b)
Basement
membrane
Free surface
of tissue
Stretched
transitional
epithelium
Connective
tissue
(a)
(b)
Basement
membrane
Underlying
connective tissue
b: © The McGraw-Hill Companies, Inc./Al Telser, photographer
(c)
(d)
b,d: © Ed Reschke
8
Glandular Epithelium
• Composed of cells that are specialized to produce and
secrete substances
• There are two (2) types:
• Endocrine glands are ductless (key word: hormone)
• Exocrine glands have ducts
• Unicellular exocrine gland:
• Composed of one cell
• Goblet cell
• Multicellular exocrine gland:
• Composed of many cells
• Sweat glands, salivary glands, etc.
• Simple and compound
9
Structural Types of
Exocrine Glands
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Tissue surface
Duct
Secretory portion
Simple tubular Simple branched
tubular
Compound tubular
Simple coiled
tubular
Compound alveolar
Simple branched
alveolar
10
Types of Glandular Secretions
• Merocrine Glands • Apocrine Glands
• Fluid product
• Salivary glands
• Pancreas gland (?)
• Sweat glands
•Serous Fluid
•Mucus
Intact
cell
Secretion
• Holocrine Glands
• Cellular product
• Portions of cells
• Mammary glands
• Ceruminous glands
Pinched off
portion of cell
(secretion)
• Secretory products
• Whole cells
• Sebaceous glands
Disintegrating cell
and its contents
(secretion)
New cell
forming by
mitosis and
cytokinesis
(a) Merocrine gland
(b) Apocrine gland
(c) Holocrine gland
11
Connective Tissues
• General characteristics:
• Most abundant tissue type
• Many functions:
• Bind structures
• Provide support and protection
• Serve as frameworks
• Fill spaces
• Store fat
• Produce blood cells
• Protect against infections
• Help repair tissue damage
• Have an extracellular matrix
• Have varying degrees of vascularity
• Have cells that usually divide
12
Connective Tissue
Major Cell Types Present
• Fibroblasts
• Fixed cell
• Most common cell
• Large, star-shaped
• Produce fibers
• Macrophages
• Wandering cell
• Phagocytic
• Important in injury or
infection
• Mast cells
• Fixed cell
• Release heparin
• Release histamine
13
Connective Tissue
Fiber Types Present
• Collagenous fibers
• Elastic fibers
• Thick
• Bundles of microfibrils
• Composed of collagen
embedded in elastin
• Great tensile strength
• Fibers branch
• Abundant in dense CT
• Elastic
• Hold structures together
• Vocal cords, air passages
• Tendons, ligaments
• Reticular fibers
• Very thin collagenous fibers
• Highly branched
• Form supportive networks
14
Connective Tissues
• Connective Tissue Proper:
• Specialized Connective Tissue:
• Loose connective tissue
• Cartilage
• Adipose tissue
• Bone
• Reticular connective tissue
• Blood
• Dense connective tissue
• Elastic connective tissue
15
Connective Tissue Types
• Loose Connective Tissue
• Adipose Tissue
• Mainly fibroblasts
• Fluid to gel-like matrix
• Collagenous fibers
• Elastic fibers
• Bind skin to structures
• Beneath most epithelia
• Blood vessels nourish
nearby epithelial cells
• Between muscles
• Adipocytes
• Cushions
• Insulates
• Store fats
• Beneath skin
• Behind eyeballs
• Around kidneys and heart
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Cytsol
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Fat droplet
Collagenous
fiber
Cell
membrane
Fibroblast
Nucleus
(a)
Ground
substance
(b)
Elastic
fiber
(a)
(b)
b: © The McGraw-Hill Companies, Inc./Dennis Strete, photographer
16
b: © The McGraw-Hill Companies, Inc./Dennis Strete, photographer
Connective Tissue Types
• Reticular Connective Tissue
• Dense Connective Tissue
• Composed of reticular fibers
• Supports internal organ walls
• Walls of liver, spleen,
lymphatic organs
• Packed collagenous fibers
• Elastic fibers
• Few fibroblasts
• Bind body parts together
• Tendons, ligaments, dermis
• Poor blood supply
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Fibroblasts
Collagenous
fibers
Collagenous
fibers
White blood
cell
(a)
(b)
Fibroblast
(a)
(b)
b: © The McGraw-Hill Companies, Inc./Dennis Strete, photographer
b: © The McGraw-Hill Companies, Inc./Al Telser, photographer
17
Connective Tissue Types
• Elastic Connective Tissue
• Bone (Osseous Tissue)
• Abundant in elastic fibers
• Some collagenous fibers
• Fibroblasts
• Attachments between bones
• Walls of large arteries, airways, heart
• Solid matrix
• Supports
• Protects
• Forms blood cells
• Attachment for muscles
• Skeleton
• Osteocytes in lacunae
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Collagenous
fibers
Osteon
Lamella
Fibroblast
Central
canal
Elastic fibers
Osteocyte
in lacuna
(a)
(b)
Canaliculi
(a)
(b)
b: © The McGraw-Hill Companies, Inc./Al Telser, photographer
Osteocyte
Nucleus
Cell process in
canaliculus
b: © The McGraw-Hill Companies, Inc./Dennis Strete, photographer
18
21
Connective Tissue Types
• Hyaline cartilage
• Cartilage
• Rigid matrix
• Chondrocytes in lacunae
• Poor blood supply
• Three (3) types:
• Hyaline Cartilage
• Elastic Cartilage
• Fibrocartilage
• Most abundant
• Ends of bones
• Nose, respiratory passages
• Embryonic skeleton
• Elastic cartilage
• Flexible
• External ear, larynx
• Fibrocartilage
• Very tough
• Shock absorber
• Intervertebral discs
• Pads of knee and pelvic girdle
19
Connective Tissue Types
Three (3) types of cartilage:
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Elastic fibers
Nucleus
Nucleus
Lacuna
Lacuna
Chondrocyte
Chondrocyte
Extracellular
matrix
(a)
Extracellular
matrix
(b)
(a)
(b)
b: © The McGraw-Hill Companies, Inc./Al Telser, photographer
b: © The McGraw-Hill Companies, Inc./Al Telser, photographer
Hyaline Cartilage
Elastic Cartilage
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Lacuna
Chondrocyte
Nucleus
Collagenous
fiber
Extracellular
matrix
(a)
(b)
b: © The McGraw-Hill Companies, Inc./Al Telser, photographer
Fibrocartilage
20
Connective Tissue Types
• Blood
• Fluid matrix called plasma
• Red blood cells
• White blood cells
• Platelets
• Transports
• Defends
• Involved in clotting
• Throughout body in blood
vessels
• Heart
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White blood
cell
Red blood
cells
Plasma
(extracellular
matrix of blood)
Platelets
(a)
(b)
b: © The McGraw-Hill Companies, Inc./Al Telser, photographer
21
Types of Membranes
• There are four (4) types of epithelial membranes:
1. Serous Membranes
• Line body cavities that
do not open to the
outside
• Reduce friction
• Inner lining of thorax
and abdomen
• Cover organs of thorax
and abdomen
• Secrete serous fluid
2. Mucous Membranes
• Line tubes and organs
that open to outside world
• Lining of mouth, nose,
throat, etc.
• Secrete mucus
3. Cutaneous Membranes
• Covers body
• Skin
4. Synovial Membranes
• Composed entirely of
connective tissue
• Lines joints
22
Muscle Tissues
• Skeletal muscle
• General characteristics:
• Muscle cells also called
muscle fibers
• Contractile
• Three (3) types:
• Skeletal muscle
• Smooth muscle
• Cardiac muscle
• Attached to bones
• Striated
• Voluntary
• Smooth muscle
• Walls of organs
• Skin
• Walls of blood vessels
• Involuntary
• Non-striated
• Cardiac muscle
• Heart wall
• Involuntary
• Striated
• Intercalated discs
23
Muscle Tissue
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
Striations
Cytoplasm
Nucleus
Nuclei
Portion of a
muscle fiber
(a)
(b)
(a)
(b)
b: © The McGraw-Hill Companies, Inc./Dennis Strete, photographer
b: © The McGraw-Hill Companies, Inc./Al Telser, photographer
Skeletal Muscle
Smooth Muscle
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Striations
Nucleus
Intercalated
disc
(a)
(b)
b: © The McGraw-Hill Companies, Inc./Al Telser, photographer
24
Cardiac Muscle
Nervous Tissue
• Found in brain, spinal cord, and
peripheral nerves
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• Functional cells are neurons
Cellular
process
Cytoplasm
• Neuroglial cells support and
bind nervous tissue components
• Sensory reception
Nucleus
Cell
membrane
Neuroglial
cells
(a)
(b)
b: © Ed Reschke.
• Conduction of nerve impulses
25