Tissues. 10/6/20152 What is Histology? Study of Tissues.
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Transcript of Tissues. 10/6/20152 What is Histology? Study of Tissues.
Tissues
04/19/23 2
What is Histology?
Study of Tissues
Tissues
• Groups of cells similar in structure and function
• Types of tissues– Epithelial tissue– Connective tissue– Muscle tissue– Nerve tissue
Tissues
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Four Types of Tissues
• Types of tissue
– Epithelial tissue
• Covers exposed surfaces
• Lines internal passageways
• Forms glands
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Four Types of Tissues• Types of Tissue (cont’d)
– Connective tissue• Fills internal spaces
• Supports other tissues
• Transports materials
• Stores energy
– Muscle tissue• Specialized for contraction
• Skeletal muscle, heart muscle, and walls of hollow organs
– Neural tissue• Carries electrical signals from one part of the body
to another
Figure 4.1
Nervous tissue: Internal communication• Brain, spinal cord, and nerves
Muscle tissue: Contracts to cause movement• Muscles attached to bones (skeletal)• Muscles of heart (cardiac)• Muscles of walls of hollow organs (smooth)
Epithelial tissue: Forms boundaries between different environments, protects, secretes, absorbs, filters• Skin surface (epidermis)• Lining of GI tract organs and other hollow organs
Connective tissue: Supports, protects, bindsother tissues together• Bones• Tendons• Fat and other soft padding tissue
Epithelial Tissue
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• Forms the coverings of all of the body’s surfaces
• Lines body cavities • Functions:
– Protection– Secretion– Absorption– Excretion– Filtration– Diffusion– Sensory Reception
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Classification of Epithelia
• Singular epithelium; plural
epithelia
• Classes of Epithelia
– Based on shape• Squamous epithelia: thin and flat
• Cuboidal epithelia: square shaped
• Columnar epithelia: tall, slender rectangles
– Based on layers• Simple epithelium: single layer of cells
• Stratified epithelium: several layers of cells
Figure 4.2a
Stratified
Simple
Apical surface
Basal surface
Apical surface
Basal surface
(a) Classification based on number of cell layers.
Figure 4.2b
Squamous
Cuboidal
Columnar(b) Classification based on cell shape.
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Classification of Epithelia
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Classification of Epithelia
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Types of Epithelial Tissue
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Simple Squamous
• Allows for diffusion, filtration, and osmosis
• Examples:– Lines heart– Lines Blood
vessels– Lines Alveoli
Epithelia: Simple Squamous
Figure 4.2a
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Stratified Squamous
• Lining of smooth muscles• Superficial layer of skin• Esophagus, mouth, vagina• Aides in protection
Figure 4.3e
(e) Stratified squamous epithelium
Description: Thick membranecomposed of several cell layers;basal cells are cuboidal or columnarand metabolically active; surfacecells are flattened (squamous); in thekeratinized type, the surface cells arefull of keratin and dead; basal cellsare active in mitosis and produce thecells of the more superficial layers.
Function: Protects underlyingtissues in areas subjected to abrasion.
Location: Nonkeratinized type formsthe moist linings of the esophagus,mouth, and vagina; keratinized varietyforms the epidermis of the skin, a drymembrane.
Photomicrograph: Stratified squamous epitheliumlining the esophagus (285x).
Stratifiedsquamousepithelium
Nuclei
Basementmembrane
Connectivetissue
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Simple Cuboidal
• Aides in secretion and absorption• Examples
– Surface of ovaries– Kidney tubules
Epithelia: Simple Cuboidal
Figure 4.2b
• Single layer of cubelike cells with large, spherical central nuclei
• Function in secretion and absorption
• Present in kidney tubules, ducts and secretory portions of small glands, and ovary surface
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Stratified Cuboidal• Aides in protection• Examples:
– Sweat gland ducts– Male urethra
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Classification of Epithelia
Figure 4–4 Cuboidal Epithelia.
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Simple Columnar (NON-CILIATED)
• Lines: – GI tract– Gall bladder
• Aides in:– Secretion – Absorption
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Ciliated Simple Columnar• Located in:
– Respiratory tract– Fallopian tubes– Uterus– Sinuses
Epithelia: Simple Columnar
Figure 4.2c
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Transitional
• Located in:– Urinary bladder– Uterus– Urethra
Epithelia: Transitional
Figure 4.2f
• Several cell layers, basal cells are cuboidal, surface cells are dome shaped
• Stretches to permit the distension of the urinary bladder
• Lines the urinary bladder, ureters, and part of the urethra
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Pseudostratified Columnar
• Aides in the movement of material• CiliatedUpper Respiratory tract
• Non-ciliatedEpididymus and male urethra
Figure 4.3d
(d) Pseudostratified columnar epithelium
Description: Single layer of cells ofdiffering heights, some not reachingthe free surface; nuclei seen atdifferent levels; may contain mucus-secreting cells and bear cilia.
Function: Secretion, particularly ofmucus; propulsion of mucus byciliary action.
Location: Nonciliated type in male’ssperm-carrying ducts and ducts oflarge glands; ciliated variety linesthe trachea, most of the upperrespiratory tract.
Photomicrograph: Pseudostratified ciliatedcolumnar epithelium lining the human trachea (570x).
Trachea
Cilia
Pseudo-stratifiedepitheliallayer
Basementmembrane
Mucus ofmucous cell
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Classification of Epithelia
Figure 4–5 Columnar Epithelia.
Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Classification of Epithelia
Figure 4–5 Columnar Epithelia.
Identify the tissues
Connective Tissues
Connective Tissue
• Most abundant and widely distributed tissue type
• Four classes– Connective tissue proper– Cartilage– Bone tissue– Blood
Table 4.1
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Functions
• Bind structures together• Supports the organs and the
body (Framework)• Stores fat (Insulation)• Transports substances
(blood)• Protects from disease• Helps repair tissue damage
Figure 4.7
Macrophage
Fibroblast
Lymphocyte
Fat cell
Mast cell
Neutrophil
Capillary
Cell types Extracellularmatrix
Fibers• Collagen fiber• Elastic fiber• Reticular fiber
Ground substance
Connective Tissue Proper
• Types:– Loose
connective tissue• Areolar• Adipose• Reticular
– Dense connective tissue• Dense regular• Dense irregular• Elastic
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Types1. Areolar (loose)
• Stretchable, superficial, soft tissue
• Examples:• Surrounds blood vessels and
nerves• Attaches skin to muscles
(Fascia)
Connective Tissue Proper: Loose
Figure 4.8b
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2. Adipose:• Functions
– Stores Fats– Protects and supports– Insulates – Food reservoir
• Located anywhere fat is in excess
Connective Tissue Proper: Loose
Figure 4.8c
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3. Reticular:• Functions
– Forms network of spleen, lymph nodes, and bone marrow
– Provides defense against microorganisms
Connective Tissue Proper: Loose
Figure 4.8d
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4. Dense (fibrous):• Provide flexible but strong
connections• Examples:
– Tendons (Bone-Muscle)– Ligaments (Bone-Bone)– Aponeuroses (Muscle-
Muscle)
Fibrous Connective Tissue
Tendons = muscles to bones Ligaments = bones to bones
Connective Tissue Proper: Dense Regular
Figure 4.8e
Figure 4.8e
(e) Connective tissue proper: dense connective tissue, dense irregular
Description: Primarilyirregularly arranged collagenfibers; some elastic fibers;major cell type is the fibroblast.
Function: Able to withstandtension exerted in manydirections; provides structuralstrength.
Location: Fibrous capsules oforgans and of joints; dermis ofthe skin; submucosa ofdigestive tract.
Photomicrograph: Dense irregularconnective tissue from the dermis of theskin (400x).
Collagenfibers
Nuclei offibroblasts
Fibrousjointcapsule
Figure 4.8f
(f) Connective tissue proper: dense connective tissue, elastic
Description: Dense regularconnective tissue containing a highproportion of elastic fibers.
Function: Allows recoil of tissuefollowing stretching; maintainspulsatile flow of blood througharteries; aids passive recoil of lungsfollowing inspiration.
Location: Walls of large arteries;within certain ligaments associatedwith the vertebral column; within thewalls of the bronchial tubes.
Elastic fibers
Aorta
HeartPhotomicrograph: Elastic connective tissue inthe wall of the aorta (250x).
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• Bone->Compact and spongy
• Blood->55% liquid/plasma
45% formed elements
Specialized Types
Connective Tissue: Bone (Osseous Tissue)
Figure 4.8j
Connective Tissue: Blood
Figure 4.8k
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• Cartilage->Hyaline
Fibrous
Elastic
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Supportive Connective Tissues
Figure 4–14 The Types of Cartilage.
Figure 4.8g
(g) Cartilage: hyaline
Description: Amorphous but firmmatrix; collagen fibers form animperceptible network; chondroblastsproduce the matrix and when mature(chondrocytes) lie in lacunae.
Function: Supports and reinforces;has resilient cushioning properties;resists compressive stress.
Location: Forms most of theembryonic skeleton; covers the endsof long bones in joint cavities; formscostal cartilages of the ribs; cartilagesof the nose, trachea, and larynx.
Photomicrograph: Hyaline cartilage from thetrachea (750x).
Costalcartilages
Chondrocytein lacuna
Matrix
Figure 4.8h
(h) Cartilage: elastic
Description: Similar to hyalinecartilage, but more elastic fibersin matrix.
Function: Maintains the shapeof a structure while allowinggreat flexibility.
Location: Supports the externalear (pinna); epiglottis.
Photomicrograph: Elastic cartilage fromthe human ear pinna; forms the flexibleskeleton of the ear (800x).
Chondrocytein lacuna
Matrix
Figure 4.8i
(i) Cartilage: fibrocartilage
Description: Matrix similar tobut less firm than that in hyalinecartilage; thick collagen fiberspredominate.
Function: Tensile strengthwith the ability to absorbcompressive shock.
Location: Intervertebral discs;pubic symphysis; discs of kneejoint.
Photomicrograph: Fibrocartilage of anintervertebral disc (125x). Special stainingproduced the blue color seen.
Intervertebraldiscs
Chondrocytesin lacunae
Collagenfiber
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• All have nerve supply (Except Cartilage)
• Very Vascular (Except Cartilage)
• All consist of cells and matrix– Matrix=fibers between the
cells
Muscle Tissue
Muscle Tissue
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Components
• Made up of cells that can shorten or contract in order to produce movement in body parts
• Well supplied with blood vessels• Cells are long and slender
(muscle fibers)• Actin and myosin are contractile
proteins.– http://www.sci.sdsu.edu/movies/acti
n_myosin.html
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3 Types of Muscle Tissues
1. Skeletal->regular (voluntary)• Aka. Striated (striped)• Many nuclei per cell b/c extremely long
2. Smooth->intestines (involuntary)• Non-striated
1. Cardiac->heart (involuntary)• Striated
Figure 4.10a
(a) Skeletal muscle
Description: Long, cylindrical,multinucleate cells; obviousstriations.
Function: Voluntary movement;locomotion; manipulation of theenvironment; facial expression;voluntary control.
Location: In skeletal musclesattached to bones oroccasionally to skin.
Photomicrograph: Skeletal muscle (approx. 460x).Notice the obvious banding pattern and thefact that these large cells are multinucleate.
Nuclei
Striations
Part ofmuscle fiber (cell)
Figure 4.10b
(b) Cardiac muscle
Description: Branching, striated, generally uninucleate cells that interdigitate atspecialized junctions (intercalated discs).
Function: As it contracts, it propels blood into the circulation; involuntary control.Location: The walls of the heart.
Photomicrograph: Cardiac muscle (500X);notice the striations, branching of cells, andthe intercalated discs.
Intercalateddiscs
Striations
Nucleus
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Muscle Tissue
Figure 4–18 Muscle Tissue.
Figure 4.10c
(c) Smooth muscle
Description: Spindle-shapedcells with central nuclei; nostriations; cells arranged closely to form sheets.
Function: Propels substancesor objects (foodstuffs, urine,a baby) along internal passage-ways; involuntary control.Location: Mostly in the wallsof hollow organs.
Photomicrograph: Sheet of smooth muscle (200x).
Smoothmusclecell
Nuclei
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Muscle Tissue
Figure 4–18 Muscle Tissue.
Nervous Tissue
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• Located in the brain, spinal cord, and nerves
• Coordinates and controls many of the bodies activities
• Stimulates muscle contractions
• Creates awareness• Has a role in emotions,
memory, and reasoning.
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Figure 4.9
Photomicrograph: Neurons (350x)
Function: Transmit electricalsignals from sensory receptorsand to effectors (muscles andglands) which control their activity.
Location: Brain, spinalcord, and nerves.
Description: Neurons arebranching cells; cell processesthat may be quite long extend fromthe nucleus-containing cell body;also contributing to nervous tissueare nonirritable supporting cells(not illustrated).
Dendrites
Neuron processes Cell body
Axon
Nuclei ofsupportingcells
Cell bodyof a neuron
Neuronprocesses
Nervous tissue
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Tissue Injuries and Repair
• Tissues respond to injuries to
maintain homeostasis
– Cells restore homeostasis with
two processes
• Inflammation
•Regeneration
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Tissue Injuries and Repair
• Inflammation = inflammatory
response
– The tissue’s first response to injury
• Signs and symptoms of the inflammatory
response include
– Swelling
– Redness
– Heat
– Pain
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Tissue Injuries and Repair
• Inflammatory Response
– Can be triggered by
• Trauma (physical injury)
• Infection (the presence of harmful
pathogens)
Figure 4.12, step 1
Scab
Blood clot inincised wound
Epidermis
Vein
Inflammatorychemicals
Inflammation sets the stage:• Severed blood vessels bleed and inflammatory chemicals are
released.• Local blood vessels become more permeable, allowing white
blood cells, fluid, clotting proteins and other plasma proteinsto seep into the injured area.
• Clotting occurs; surface dries and forms a scab.
Migrating whiteblood cell
Artery
1
Figure 4.12, step 2
Regeneratingepithelium
Area ofgranulationtissueingrowth
FibroblastMacrophage
Organization restores the blood supply:• The clot is replaced by granulation tissue, which restores
the vascular supply.• Fibroblasts produce collagen fibers that bridge the gap.• Macrophages phagocytize cell debris.• Surface epithelial cells multiply and migrate over the
granulation tissue.
2
Figure 4.12, step 3
Regeneratedepithelium
Fibrosedarea
Regeneration and fibrosis effect permanent repair:• The fibrosed area matures and contracts; the epitheliumthickens.• A fully regenerated epithelium with an underlying area ofscar tissue results.
3
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Tissue Injuries and Repair
• Regeneration
– When the injury or infection is
cleaned up
• Healing (regeneration) begins
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Aging and Tissue
• Effects of Aging
– Chemical and structural tissue
changes
• Thinning epithelia and connective tissues
• Increased bruising and bone brittleness
• Joint pain and broken bones
• Cardiovascular disease
• Mental deterioration
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Aging and Tissue
• Aging and Cancer Incidence
– Cancer rates increase with age
• 1 in 4 people in the United States
develops cancer
• Cancer is the #2 cause of death in
the United States
• Environmental chemicals and
cigarette smoke cause cancer
Cell Differentiation
• All cells carry complete DNA instructions for all body functions
• Cells specialize or differentiate– To form tissues (liver cells, fat cells, and
neurons)
– By turning off all genes not needed by that cell
• All body cells, except sex cells, contain the same 46 chromosomes
• Differentiation depends on which genes are active and which are inactive
- CancerWhat Is Cancer?
• Cancer is a disease in which cells grow and divide uncontrollably, damaging the parts of the body around them.
Tumors and Cancer
• Cancer develops in steps
– Abnormal cell
– Primary tumor
– Metastasis
– Secondary tumor
Tumors and Cancer• Tumor (neoplasm)
– Enlarged mass of cells
– Abnormal cell growth and division
– Benign tumor • Contained
• Not life threatening
– Malignant tumor • Spreads into surrounding tissues (invasion)
• Starts new tumors (metastasis)