Tissues Not Kleenex Tissues are a group of

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Tissues (Not Kleenex) • Tissues are a group of cells that are similar in

Tissues (Not Kleenex) • Tissues are a group of cells that are similar in structure and function. • Histology is the study of tissues Four primary types Epithelium tissue Connective tissue Nervous tissue Muscle

Epithelial Tissue- Characteristics • Cells fit closely together • Tissue layer always has one

Epithelial Tissue- Characteristics • Cells fit closely together • Tissue layer always has one free surface • The lower surface is bound by a basement membrane • Avascular (have no blood supply) • Regenerate easily if well nourished

How is epithelial tissue named? • CELL SHAPE • Squamous shape – Thin, flat

How is epithelial tissue named? • CELL SHAPE • Squamous shape – Thin, flat cells – Look like fried eggs • Cuboidal shape – square shape- cross section – 6 sided polygon- surface • Columnar – Rectangular- cross section – Polygonal- surface view

How is epithelial tissue named? • Number of cell layers – Simple – one

How is epithelial tissue named? • Number of cell layers – Simple – one layer Stratified – more than one layer

Layers (continued) • Pseudostratified – Appears to be multiple layers – All cells reach

Layers (continued) • Pseudostratified – Appears to be multiple layers – All cells reach the basement layer

How do we name them? We put the shape and layer numbers together!

How do we name them? We put the shape and layer numbers together!

Simple Squamous *Single layer *Squamous shape *Lining of body cavity, lungs, blood vessels

Simple Squamous *Single layer *Squamous shape *Lining of body cavity, lungs, blood vessels

Simple cuboidal • Single layer of cube -like cells • Common in glands and

Simple cuboidal • Single layer of cube -like cells • Common in glands and their ducts • Covers the ovaries • Forms walls of kidney tubules

Simple columnar • Simple columnar – Single layer of tall cells – Often includes

Simple columnar • Simple columnar – Single layer of tall cells – Often includes goblet cells, which produce mucus – Lines digestive tract

Pseudostratified columnar – Single layer, but some cells are shorter than others – Often

Pseudostratified columnar – Single layer, but some cells are shorter than others – Often looks like a double cell layer – Sometimes ciliated, such as in the respiratory tract – May function in absorption or secretion

Pseudostratified Columnar

Pseudostratified Columnar

Stratified squamous – Cells at the free edge are flattened – Found as a

Stratified squamous – Cells at the free edge are flattened – Found as a protective covering where friction is common – Locations • Skin • Mouth • Esophagus

Stratified cuboidal • Two layers of cuboidal cells • Usually line ducts

Stratified cuboidal • Two layers of cuboidal cells • Usually line ducts

Stratified columnar • Very rare • Large ducts

Stratified columnar • Very rare • Large ducts

Can you identify the shape? Can you identify the layers?

Can you identify the shape? Can you identify the layers?

What is the shape? How many layers? What type of tissue?

What is the shape? How many layers? What type of tissue?

What is the shape? How many layers? What type of tissue is it?

What is the shape? How many layers? What type of tissue is it?

What is the shape? How many layers? What type of tissue?

What is the shape? How many layers? What type of tissue?

What is the shape? How many layers? What are those “things” on the top?

What is the shape? How many layers? What are those “things” on the top?

Connective Tissue • Found everywhere in the body · Includes the most abundant and

Connective Tissue • Found everywhere in the body · Includes the most abundant and widely distributed tissues · Functions · Binds body tissues together · Provides protection

Types of Connective Tissue • • • Bone Cartilage Dense connective tissue Loose connective

Types of Connective Tissue • • • Bone Cartilage Dense connective tissue Loose connective tissue Blood

What characteristics do all connective tissue have? • Matrix: material surrounding the cell –

What characteristics do all connective tissue have? • Matrix: material surrounding the cell – Varies in structure • Protein fibers – Found in matrix – Various types

Bone (osseous) Tissue • Bone cells (osteocytes) are in cavities called (lacunae). • The

Bone (osseous) Tissue • Bone cells (osteocytes) are in cavities called (lacunae). • The matrix is very hard and contains calcium salts and collagen fibers

Cartilage • 3 Main types of cartilage – Hyaline cartilage (most abundant type) •

Cartilage • 3 Main types of cartilage – Hyaline cartilage (most abundant type) • Larynx • Attaches ribs to sternum • Ends of bones (joints) – Elastic cartilage (where elasticity is needed) • Ears • End of the nose – Fibrocartilage • Discs between vertebrae

Cartilage

Cartilage

Dense connective tissue • Mostly collagen fibers • Fibroblasts are cells that make the

Dense connective tissue • Mostly collagen fibers • Fibroblasts are cells that make the fibers – Ligaments- connects bone to bone – Tendons- connects skeletal muscle to bone

Loose connective tissue • 1) Areolar-most abundant – Soft – Cushions body organs –

Loose connective tissue • 1) Areolar-most abundant – Soft – Cushions body organs – Reservoir for water and salt

Loose Connective Tissue • 2) Adipose- known as fat – Insulates the body –

Loose Connective Tissue • 2) Adipose- known as fat – Insulates the body – Protects the kidneys – Cushions the eyeballs in the sockets

Loose Connective Tissue • Reticular-delicate – Found in lymphocytes

Loose Connective Tissue • Reticular-delicate – Found in lymphocytes

Blood • Blood contains blood cells and a fluid matrix called plasma • Fibers

Blood • Blood contains blood cells and a fluid matrix called plasma • Fibers in the plasma (fibrinogen)are only visible during blood clotting

Muscle Tissue • Function is to produce movement • Three types – Skeletal muscle-

Muscle Tissue • Function is to produce movement • Three types – Skeletal muscle- movement of skeleton – Cardiac muscle- heart – Smooth muscle-digestive organs, hollow organs

Skeletal Muscle Can be controlled voluntarily Cells attach to connective tissue Cells are striated

Skeletal Muscle Can be controlled voluntarily Cells attach to connective tissue Cells are striated Cells have more than one nucleus

Cardiac Muscle · Found only in the heart · Cells attached to other cardiac

Cardiac Muscle · Found only in the heart · Cells attached to other cardiac muscle cells at intercalated disks · Function is to pump blood (involuntary) · Cells are striated · One nucleus per cell

Cardiac Muscle

Cardiac Muscle

Cardiac Tissue after Cocaine Abuse

Cardiac Tissue after Cocaine Abuse

Cardiac Muscle After a Myocardial Infarction

Cardiac Muscle After a Myocardial Infarction

Smooth muscle Involuntary muscle Surrounds hollow organs Attached to other smooth muscle cells No

Smooth muscle Involuntary muscle Surrounds hollow organs Attached to other smooth muscle cells No visible striations One nucleus per cell

Nervous Tissue • Comprised of neurons and supporting cells • Neurons: – Responsible for

Nervous Tissue • Comprised of neurons and supporting cells • Neurons: – Responsible for conducting electrochemical impulses – Elongated (can be up to 3 feet) • Supporting cells: – Insulation – Unknown function

Neurons

Neurons

Supporting Cells

Supporting Cells

Tissue Repair • Not all tissues can be repaired (healed). – Heart muscle, nervous

Tissue Repair • Not all tissues can be repaired (healed). – Heart muscle, nervous tissue (CNS) none – Skeletal muscle can but it is poor • Occurs in 2 stages – Regeneration • Replacement of destroyed tissue by same type cells • Cells migrate towards the open wound and fill it in – Fibrosis • Fibrous connective tissue replaces the damaged area • Considered scar tissue- strong but lacks flexability

Tissue Regeneration • Within 2 minutes a plug of platelets and other fibers form

Tissue Regeneration • Within 2 minutes a plug of platelets and other fibers form a blood clot at the site of tissue damage. • Within hours wbc’s (neutrophils) begin the inflammatory response. It causes increase blood flow. They eat the cellular debris, die and become “pus”. • Granulation tissue is formed. New blood vessels grow and fibroblasts add collagen fibers to bridge the gap. • Epithelial cells divide by mitosis and migrate over the granulation tissue • Macrophages arrive later under the scab and ingest the remaining debris. • The scab detaches and the newly formed tissue is exposed

Developmental aspects of cells and tissues • All life begins as a single cell

Developmental aspects of cells and tissues • All life begins as a single cell • Mitosis continues in most cells through puberty until adult body size is reached • Cells that wear away (epithelial) continue to divide through mitosis • Liver cells can regenerate occasionally • Heart and CNS (brain) are amitotic • Aging process is a decrease in: mitosis, the fibers produced in ECM and regeneration