Tissues

Front 1

Tissues

Back 1

collections of specialized cells and cell products that perform a limited number of functions.

Front 2

Histology

Back 2

is the study of tissues

Front 3

Four primary tissue types: "ECMN"

Back 3

-epithelial

-connective

-muscular

-neural

Front 4

Epithelial Tissue:

Back 4

covers exposed surfaces or lines internal cavities or passageways and forms glands.

Front 5

Characteristics of Epithelial Tissue: 'CP'

Back 5

1. Cellularity

2.Polarity

Front 6

1. Cellularity:

Back 6

Epithelial cells are always CONtIGOUS cells bound closely together by cell junctions. In other words, there is little intercellular space.

Front 7

2. Polarity:

Back 7

Epithelial cells have exposed surfaces and surfaces for attachment with neighboring cells and tissues. These surfaces are called:

1. Apical surface

2. Basolateral surface

Front 8

a. Apical surface:

Back 8

for the side that faces the external or internal space lined by the epithelium

Front 9

b. Basolateral surface:

Back 9

for the side attached to the underlying tissue and the sides attached to neighboring epithelial cells.

Front 10

3. Attachment:

Back 10

the BASAL surface (part of the BASOlateral surface) is attached to the underlying tissue by a basal lamina (aka. basement membrane)

Front 11

4. Avascularity:

Back 11

Refers to the absence of blood vessels.

Nutrients are obtained by diffusion or absorption across the apical and basal surfaces.

Front 12

5. Regeneration:

Back 12

Cells that become damaged, worn out or abraded are replaced by division of STEM CELLS.

Front 13

6.Arranged into Sheets or Layers

Back 13

Epithelial cells are arranged in layers one or more cells thick.

Front 14

Functions:

1. Physical Protection:

Back 14

Protects tissue from abrasion, dehydration, and damaging chemical or biological agents.

Front 15

2. Control Permeability:

Back 15

Controls the passage of material into (absorption) and out of (secretion) tissue.

Front 16

3. Provide Sensation:

Back 16

Epithelium has nerve ending and specialized epithelium cells that detect environmental changes. A NEUROEPITHELIUM is specialized sensory epithelium.

Front 17

4. Produce Specialized Secretions:

Back 17

GLANDS are derived from epithelial cells.

Front 18

The epithelium is GLANDULAR EPITHELIUM when...

Back 18

most or all epithelial cells produce secretions.

Front 19

These glands are derived from epithelial tissue:

Back 19

Endocrine and Exocrine

Front 20

Specializations of Epithelial Cells:

Epithelial cells specialized for absorption or secretions have....

Back 20

MICROVILI on the apical surface that increase the surface area for exchange of materials.

Front 21

Stereocilia:

Back 21

are very long microvilli that are found along portions of the male reproductive tract and on receptor cells of the inner ear.

Front 22

Ciliates epithelium :

Back 22

has CILIA on the apical surface to move fluids. Ciliated epithelium is typical of the upper respiratory tract. Cilia are also found on the epithelial cells lining the oviducts.

Front 23

Maintaining the Integrity of Epithelium:

maintained by CELL JUNCTIONS

Back 23

1. Intercellular Connections2. Attachment to Basal Lamina (Basement Membrane)

2. Attachment to Basal Laminia (Basement Membrane).

Front 24

a. lamina lucida:

b. lamina densa:

Back 24

a. A layer next to the epithelium containing glycoproteins and a network of microfilaments

b. A layer next to the connective tissue contains protein fibers produced by the connective tissue cells.

Front 25

3. Maintenance and Repair:

Back 25

-cell renewal

-Germinative (stem) cells continually divide to replace cells lost due to wear and tear.

Front 26

Basis for Classification:

1. Layers

ex: Simple Epithelium

Back 26

-one layer thick

-found in protected areas such as VENTRAL BODY CAVITY, heart chambers and lining of blood vessels.

-involved with secretion, absorption and filtration

Front 27

2. Shape of Cells

Back 27

-has more than one layer of cells resting on the basal lamina and is subjected to mechanical or chemical stresses.

Front 28

Classification of Epithelium:

Simple Squamous

Back 28

Very delicate and the thinness of the cells readily allow molecules to pass through it. Found in regions where rapid exchange of molecules is needed such as the AVEOLI of lungs and ENDOTHELIA of capillaries.

-provides slippers surface for there serous (watery) membranes on the ventral body cavity

Front 29

a. Mesothelium:

Back 29

refers to the simple squamous epithelium that lines the ventral body cavity

Front 30

b. Endothelium

Back 30

is the simple squamous epithelium that lines the interior of the heart chambers and blood vessels.

Front 31

Stratified Squamous

Back 31

the type of epithelium that typically consists of many layers of cells and is found where mechanical stresses are severe. Stratified squamous can be further subcategorized into:

Front 32

a. Keratinized:

b. Nonkeratinized:

Back 32

a. The apical layers of epithelial cells become packed with intermediate filaments of KERATIN; a protein that gives toughness and water-resistance

b. The apical layers lack water resistance and must be kept moist by glandular secretions. Found lining the oral cavity, esophagus, rectum, anus, and vagina.

Front 33

Simple Cuboidal

Back 33

This type of epithelium sometimes lines the ducts of sweat glands and the larger ducts of exocrine glands.

Front 34

Transitional Epithelium

Back 34

-is stratified with plump cuboidal cells on the surface.

-is designed to accommodate the stretching that occurs in the urinary bladder and ureters while maintaining the impermeable barrier these locations require.

Front 35

Simple Columnar

Back 35

-is simliar to simple cuboidal except that the cells appear taller than wide

-provides some protection and is found in regions where active absorption or secretion cures including the stomach, intestinal tract, uterine tubes, and excretory ducts.

-cells show distance polarity with the nuclei crowded into a band near the basal lamina

Front 36

Pseudostratified Columnar

Back 36

-there is only a single layer of cells but there are appears to be multiple layer because of the varying locations of the nuclei

-typically found lining the upper respiratory tracts as pseudo stratified ciliated columnar epithelium (PCCE) also male reproductive tract

Front 37

Stratified Columnar

Back 37

is rare and is found lining portions of the pharynx, urethra, anus, and large ducts

Front 38

Glandular Epithelium

Back 38

-may develop into gland cells that produce secretions.

Front 39

Classifications of Glands:

1. Type of Secretion

Back 39

-Exocrine secretions are discharged onto the epithelial surface. Glandular cells may move away from the epithelial surface but remain connected by tubes called DUCTS.

-secret mucins, enzymes, water and waste products.

Front 40

Nature of Secretion:

a. Serous

Back 40

-glands that secrete a watery secretion containing enzymes

Front 41

b. Mucous

Back 41

-glands the secrete mucins that absorb water to form MUCUS

Front 42

c. Mixed

Back 42

-glands that contain a mixture of cells secreting both serous and mucous secretions.

Front 43

Endocrine:

Back 43

-cells that secret by exocytosis into the fluid surrounding the cell.

-may either be single cells or aggregation of cells and secret HORMONES that serve as chemical messengers.

SUCH AS: thyroid, adrenal or pituitary glands, are DUCTLESS

Front 44

2. Gland Structure:

Unicellular:

Back 44

-glands that are single secretory epithelial cells. The only unicellular glands are GOBLET CELLS that secret mucins.

Front 45

Multicellular glands include:

a. Glandular epithelium:

Back 45

in which all the surface cells are secretory. the epithelium that lines the lumen of the stomach is an example.

Front 46

b. Aggregations of glandular cells...

Back 46

-move away from the surface and form either exocrine or endocrine glands.

-multicellular exocrine glands have 2 components that results in further subclassifications, the secretory portion and the duct.

Front 47

The secretory portion may either be:

1.Tubular

2. Alveolar or acing

3. Tubuloalveolar

Back 47

1. when the cells are arranged in tubes

2. when the cells are arranged in blind pockets.

3. when both configurations are present.

Front 48

Ducts may either be:

1. Simple

2. Compound

Back 48

1. when it is unbranched

2. when it is branched

Front 49

3. Modes of Secretion:

a. Merocrine

Back 49

glands are the most common and release their secretions by exocytosis.

Front 50

b. Apocrine

Back 50

glands release their secretions by detachment of an APICAL PORTION OF THE CYTOPLASM.

Front 51

c. Holocrine

Back 51

glands release their secretions with the disintegration of the entire cell.

Front 52

Connective Tissues

Back 52

is found throughout the body but is never exposed to the environment

Front 53

Three Basic Components:

1. Specialized Cells

2. Extracellular Protein Fibers

3. Ground Substance

Back 53

1.-MATRIX that surrounds the cells with:

2. " "

3. A viscous, clear substance with a slippery feel and a high water content and very large macromolecules including PROTEOGLYCANS and GLYCOSAMINOGLYCANS.

Front 54

Functions:

Back 54

1. Establishes structural framework for the body e.g. bone, cartilage

2. Transports fluids and materials throughout the body. e.g blood, lymph

3. Provides protections for delicate organs e.g bone of skull, rib cage, spinal column.

4. Supports, surrounds and interconnects other tissue types. e.g. Fascia, tendons, organ capsules.

5. Stores energy. e.g adipose tissue.

6. Defends body from invasion. e.g. inflammatory cells reside and migrate through connective tissue.

Front 55

Classifications:

Back 55

connective tissue can be placed in one of three broad categories:

Front 56

1. Connective Tissue Proper

Loose/dense CT

Back 56

this type is literally connecting or binding the other tissue and hence is "proper"ly speaking connective tissue

Front 57

2. Fluid Connective Tissue

Back 57

is connective in a broader sense in that it allows substances to move from one part of the body to another, e.g blood and lymph. Matrix is essentially a fluid rather than a gel or solid.

Front 58

3. Supporting Connective Tissue

Back 58

This connective tissue supports the body against the forces of gravity but also provides physical protection and functions as levers upon which muscle can exert force, e.g cartilage and bone.

Front 59

Connective Tissue Proper

1. Cells

Fixed Cells:

a. fiberblasts/Fibrocysts

Back 59

-These cells are always present in connective tissue proper and is the most abundant cell found there.

-Fibroblasts SECRETE PROTEIN SUBUNITS that form extracellular fibers (collagen and elastic fibers) and molecules that form the ground substance.

-Differentiate from fibroblasts and maintain the connective tissue fibers of the tissue.

HYALURONAN is secreted and gives the ground substance its viscous consistency.

Front 60

b. Fixed Macrophages (Histiocytes)

Back 60

-Defensive cells that engulf damaged cells and pathogens.

-not as abundant as fibroblasts but when mobilized for defense or repair attracts other cells of the immune system.

Front 61

c. Adipocytes (Fat Cells)

Back 61

-These cells contain lipid inclusions that push other organelles to the edge of the cell.

-the number of adipocytes will vary in different regions of the body and in different individuals.

Front 62

d. Mesenchymal Cells

Back 62

These are stem cells that can divide and differentiate into the other specialized cells when needed.

Front 63

e. Mast Cells

Back 63

they secrete HISTAMINE and HEPARIN in response to injury and infection. This results in local inflammation.

Front 64

f. Melanocytes

Back 64

-gives pigmentation

-is an inclusion

-absorbs UV radiation

-synthesizes MELANIN

Front 65

Wandering Cells:

a. Free Macrophages

Back 65

-Phagocytic cells that circulate in the blood as MONOCYTES and migrate rapidly through connective tissue.

-these cells are recruited to areas of infection or tissue damage by fixed macrophages

Front 66

b. Lymphocytes

Back 66

-These cells migrate throughout the body and provide the body with specific immunity

- Lymphocytes that actively produce ANTIBODIES are called PLASMA CELLS

Front 67

C. Neutrophils and Eosinophils

Back 67

These are phagocytic cells that are smaller than macrophages and are attracted to areas of infection and injury by chemicals released by cells already at the site.

Front 68

2. Connective Tissue Fibers

Back 68

all tissue fibers are assembled from protein subunits by FIBROBLASTS

Front 69

a. Collagen

Back 69

-Collagen fibers are the most common and strongest fibers.

-These fibers combine tensile strength with flexibility

Front 70

b. Reticular

Greek: Rete- "little net" or "mesh"

Stroma= "bed" or " cells to rest on"

Back 70

-has many RETICULAR FIBERS

-forms the STROMA ( the mesh keeping cells in position) in various organs

-not as strong as collagen fibers

-PARENCHYMA - refer to the cells of the organ performing the function.

Front 71

c. Elastic

Back 71

-ELASTIN

-Recoil property

-give greater RESILIENCE

-walls of BVs--- transitional epithelium

Front 72

3. Ground Substance

Back 72

-clear, colorless and of a thick consistency (like maple syrup)

-this is the substance that surrounds the cells and fibers. It contains HYALURONAN and proteoglycans and glycoproteins.

Front 73

Types of Connective Tissue Proper:

EMBYRONIC TISSUES:

Embryonic Tissue

a. Mesenchyme

Back 73

-connective tissue found in the embryo

(unspecialized) cells in a matrix with fine fibers.

-differentiate into other kinds of tissue including adult connective tissue cells.

Front 74

b. Mucous Connective Tissue

Back 74

-embryonic connective tissue found in the umbilical cord.

-the extracellular matrix is like gelatin in consistency and is often referred to as WHARTON'S JELLY

Front 75

2. Loose Connective Tissue: ("packing material")

a. Areolar Connective Tissue

Back 75

-LEAST SPECIALIZED

-HAS ALL THE CELLS AND FIBERS found in connective tissue proper.

-immediately under the dermis.

-HIGHLY VASCULAR

-provides MAJOR PATHWAY FOR CELLS OF THE IMMUNE SYSTEM to reach sites of damage or invasion.

Front 76

b. Adipose Tissue

Back 76

-difference are arbitrary; as areolar tissue is considered adipose tissue when there is a high concentration of ADIPOCYTES.

Front 77

c. Reticular Tissue

Back 77

- predominance of RETICULAR FIBERS

-it forms the STROMA in various organs including liver, spleen, lymph nodes and bone marrow.

Front 78

3. Dense Connective Tissue "TALE"

Back 78

1. Tendons

2. Aponerouses

3. Elastic Tissue

4.Ligaments

Front 79

a. Dense Regular Connective Tissue

Back 79

-HIGH concentration of collagen fibers

---> arrayed in parallel

Front 80

1. Tendons

Back 80

-form cords that attach muscle to bone

Front 81

2. Aponeuroses "flat-sheet"

Back 81

-parallel arrays form flat sheets of connective tissue that connect flat muscles to their attachments.

Front 82

3. Elastic Tissue

Back 82

-give greater resilience

-found in the wall of large blood vessels, underlying transitional epithelium and surrounds respiratory passages.

Front 83

4. Ligaments

Back 83

-similar to tendons

-often contain a sig. number of ELASTIC FIBERS

-ELASTIC LIGAMENTS have a predominance of elastic fibers

- attaching BONE TO BONE

Front 84

b. Dense Irregular Connective Tissue

Back 84

-Bundles of collagen fibers

-EX: dermis of skin -> fibrous coverings on surface of cartilage and bone.

-forces from MANY directions

-ex. also forms tough CAPSULES AROUND ORGANS AND JOINTS

Front 85

Supporting Connective Tissue

1. Cartilage:

Back 85

-the matrix contains CHONDROITIN SULFATE and KERATIN SULFATE, that forms links with protein molecules

-FIRM but pliable

-the matrix is produced by both CHONDROBLASTS and CHONDROCYTES and is maintained by CHONDROCYTES

-chondrocytes exist in spaces of the matrix called LACUNAE

Front 86

Cartilage is....

Back 86

avascular and all nutrient and waste product exchange occurs by diffusion through the matrix.

Front 87

Formation and Growth:

Cartilage grows by two mechanisms:

Back 87

Appositional growth:

-fibroblasts of the cellular layer of the PERICHONDRIUM differentiate into chondroblasts that produce matrix and become chondrocytes when embedded in matrix.

Front 88

Interstitial growth:

Back 88

-chondrocytes within the MATRIX divide by mitosis and produce additional matrix that cause internal expansion of cartilage.

Front 89

Types of Cartilage:

Back 89

a. Hyaline Cartilage (hyaline means "glassy")

b. Elastic Cartilage

c. Fibrocartilage

Front 90

a. Hyaline Cartilage

Back 90

-most common type

-connects ribs to sternum as COSTAL CARTILAGE

-supports conducting passages ( larynx, trachea and bronchi)

-forms ARTICULAR SURFACES of moveable joints

Front 91

b. Elastic Cartilage:

Back 91

-very resilient

-found in the PINNAE of outer ear, EPIGLOTTIS and CUNIFORM CARTILAGES of the larynx and supporting the AUDITORY CANAL

Front 92

c. Fibrocartilage:

Back 92

-dense regular connective tissue and hyaline cartilage

-tougher and durable

-found in intervertebral discs, pubis symphysis, and in menisci of the knee and temporomandibular joints.

Front 93

Membranes:

4 types of membranes

Back 93

1. Mucous Membranes

-continuous with the exterior

-include digestive, urinary, reproductive and respiratory tracts

-lining is kept moist by secretions including MUCUS from MUCOUS GLANDS

-the areolar CT that attaches the epithelium to basal lamina is called LAMINS PROPRIA

Front 94

2. Serous Membranes

Back 94

-very thin and transparent and line compartments of the VENTRAL BODY CAVITY

Front 95

a. Pleura

Back 95

the lining on the LUNGS and the PLEURAL CAVITIES in which the lungs are found.

Front 96

b. Peritoneum

Back 96

the lining of the ABDOMINOPELVIC CAVITY and all organs situated there.

Front 97

c. Pericardium

Back 97

lining on the surface of the HEART and the PERICARDIAL SAC that surrounds heart

Front 98

Mesothelium

Back 98

-simple squamous epithelium of a serous membrane.

Front 99

Areolar connective tissue....

Back 99

is a thin underlying layer of tissue

-allowinf fluid to seep through and form a TRANSUDATE. (contributing to the smooth and slippery nature)

Front 100

3. Cutaneous Membrane

Back 100

-aka. SKIN.

-keratinized stratified squamous epithelium attached by areolar connective tissue to a layer of dense connective tissue

-

Front 101

4. Synovial Membrane

Back 101

-found within joint capsules

-composed of areolar connective tissue incompletely lined by "epithelial" cells.

-Secretory cells secrete SYNOVIAL FLUID that lubricates and nourishes the hyaline cartilage of the joint.