Intro to Histology: Epithelial 4.0-4.2

Question 1

Histology

Answer 1

refers to the study of tissues

Question 2

Tissues

Answer 2

Are a group of similar cells that are specialized to perform a specific function. Ex) nervous tissues are specialized to conduct nerve impulses

Question 3

Stem Cells

Answer 3

Cells that are capable of becoming a variety of cells. Ex hemocytoblast

Question 4

Toitpotent

Answer 4

The ability of a cell or group, to produce all tissues needed for development (zygote)

Question 5

Pluripotent

Answer 5

The ability of a cell to produce a limited number of different cells. ( hemocytoblast makes seven different blood cells)

Question 6

Differentiation

Answer 6

Cells specialize depending upon the environment.

Question 7

Intracellular

Answer 7

Within a cell

Question 8

Intercellular

Answer 8

Between cells

Question 9

Apoptosis

Answer 9

programmed cell death ( statifed squamous epithelium of skin)

Question 10

Nercorsis

Answer 10

Death of cells due to injury / diease

Question 11

Hypertrophy

Answer 11

Increase in size of cells

Question 12

Atrophy

Answer 12

Decrease in size or number of cells , Ex ( lack of excecise osteoporosis)

Question 13

Hyperplasia

Answer 13

Increased in number of cells , anemia causes increase RBC

Question 14

Metaplasia

Answer 14

Change in type of cell

Question 15

Neoplasia

Answer 15

Change in cellular DNA, makes different and cancerous

Question 16

Tissue Types

Answer 16

• Epithelia
• Connective
• Muscle
• Nervous

Question 17

Epithelia Tissues

Answer 17

Covers all exposed surfaces inside and out Ex ( Lining of organs, glands, skin) Composed of covering or lining that lines skin, digestive, organ walls etc.
Glandular epithelium forms the glands.

Question 18

Connective Tissues

Answer 18

Fills internal spaces, provides structural support, transports materials, stores energy Ex ( Bones, tendons, fats)

Question 19

Muscle

Answer 19

Specialized for contraction

Question 20

Nervous / Neural

Answer 20

Carriers information from one area in the body to another via electric impulses.

Question 21

Epithelial Tissues Characteristics

Answer 21

1. Cellularity:
2. Polarity
3. Attachment
4. Avascularity
5. Regeneration

Question 22

Cellularity

Answer 22

highly cellular, tight junctions

Question 23

Polarity

Answer 23

Epithelial have apical surface and basale surface and all is attached via the basement membrane.

Question 24

Attachment

Answer 24

Base of epithelium bound to the connective tissue, known as basement membrane.
Epithelia tissues are bound via tight junctions and desmosomes. The basement membrane reinforces the sheet consists of two layers–> reticular lamina (deeper) and basal lamina.

Question 25

Avasculairty

Answer 25

Lacks blood vessels, obtains nutrients absorption, it is still innervated and supplied via nerve fibers. Cells are nourished by substance diffusing from vessels into underlying connective tissues.

Question 26

Regeneration

Answer 26

Constantly lost and replaced through cell division. Some cells are exposed to friction etc.

Question 27

Epithelial Functions

Answer 27

1. Protection ( epithelial protect exposed surfaces from abrasion, dehydration, destruction) 2. Permeability ( substances that enters/ leaves), callus formation 3. Sensation ( sensitive due to large neuron connections) 4. Secretion ( gland cells that secrete protective secretions or chemical messengers in the inters.) Glandular Absorption Protective Secretory

Question 28

Epithelial Specializations

Answer 28

- Specialized for the movement of fluids over the epithelial surface - Fluids through the epithelium and production of secretions , absorption

Question 29

Maintaining Integrity through Intercellular connections

Answer 29

1. CAMS ( Cell adhesion molecules) are transmembrane proteins which bind to each other and to extra cellular materials. 2. Intercellular Cement: thin layer of proteoglycans that contain polysaccharide derivatives called hyaluronic acid. 3. Cell Junctions: specialized cells in the plasma membrane that attach a cell to another

Question 30

Cell Junctions

Answer 30

1. Gap Junctions: two cells joined via connexions, allow for communication. 2. Occluding (tight) Junctions: bound memberous proteins membrane together. Do not allow water to pass through. 3. Desmosomes: strong connections for mechanical stress. Cadherins proteins - Hemidesosomes: resemble half a desmosome, found in basement membrane to attach extracellular filaments to basal lamina. - Spot desmosomes : small discs found in intermediate filaments.

Question 31

Attachment to Basal Lamina

Answer 31

1. Basal Lauina 2 layers: - lamina Lucida (clear layer): Layer contains glycoproteins, the permeability decreases through large proteins and molecules. - Lamina Densa underneath (dense layer): Bundles of protein fibers give basement mem. strength and structure. Hemidesosomes attach the basement membrane to the epithelium.

Question 32

Regeneration

Answer 32

Stem cells near basement membrane are called Gemative layers of cells that repair the epithelial structure.

Question 33

Tissue Classifications

Answer 33

Named according to the arrangement and shape of cells in apical layer. Meaning you name based off of the top layer not the bottom or Basal layer. 1. Simple ( one layer) vs Stratified ( more than one layer thick) --> arrangement 2. Shape--> Squamous , Cuboidal, Columnar shape impacts nuclues

Question 34

GAPS

Answer 34

Glandular Absorption Protective Secretory Know what tissues look like, found, function

Question 35

Simple Squamous Epithelium

Answer 35

"one cell thick" and a squished appearance Location: Lining of the alveoli, capillaries, lymph vessels, organs Function: passive absorption ( diffusion) of gases. Secretes serous fluid to lubricate organs. Endothelium ( lining of heart) Mesothelium ( lining of ventral body cavities, serous membranes) Serous Membranes --> reduce friction and secrete serious fluid.

Question 36

Stratified Squamous Epithelium

Answer 36

Description: thick membrane of many layers Cells near the basement membrane are cuboidal or columbar and alive Cells near the surface are squamous and full of keratin and dead. Cells closer to the blood vessels can receive nutrients while as you move outward, they become depleted and die out. Location: found in aread of high wear, tear ( skin, anus, mouth lining) Kertain is tough, insoluble protein that accumulates in cells on surface. Function: The epithelium protects from cuts, bacteria, scrapes and water proofs.

Question 37

Simple Cuboidal Epithelium

Answer 37

Description: short, cube liked appearance with a large centred nucleus. Location: glands, ovaries, kidney tubules Function: cuboidal epithelium cells secrete substances in glands and in they kidney tubules they absorb water and solutes

Question 38

Transitional Epithelium

Answer 38

Description: outer cells are rounded not flattened like stratified squamous. Layers of cuboidal and elongated cells held tightly. Outer cells alive Location: Ureters, urinary bladder, part of urethra Function: able to distend allows for expansion and contraction. Prevent the passage of urine into other areas.

Question 39

Simple Columnar Epithelium

Answer 39

Description: elongated column shaped cells , one cell thick, nuclei are arranged near bottom of cells. Location: Lines the digestive tract from stomach through to rectum. Found in gallbladder and oviducts. Function: Absorption, secretion of mucous, movement of material (mucus and reproductive cells) Goblet Cells: secrete mucus which protects and lubricates the tissues. Brush Border: contains microvilli which vastly increases the surface area of the cell for absorption.

Question 40

Pseudostratified Ciliated Columnar Epithelium

Answer 40

Description: Cells vary in height and only the tallest cells reach the free surface ( simple tissue) Cell nucleus are at different heights which give it the false (pseudo) stratified look Cells are columnar shape Location: trachea, upper resp tract, sperm ducts Function: Secretes, absorbs substances. Protects the respiratory tract by sweeping dirt towards pharynx. Cilia ( sweep dirt back towards pharynx) Goblet cells ( secrete mucus which collect bacteria , moistness the resp. tract)

Question 41

Glands

Answer 41

Endocrine and exocrine

Question 42

Endocrine Glands

Answer 42

Have an intracellular effect ( inside cell) Secretes hormones into the interstitial fluid--> blood Ductless ( no ducts)

Question 43

Exocrine glands

Answer 43

Secrete onto epithelial surface Have ducts Have extracellular effect Ex (enzymes)

Question 44

Glands Structure

Answer 44

Meocrine glands: most abundant, exocytosis, meocrine sweat glands Holecrine glands: ( destroy cells) glands destroy whole cell in secretion. Ex (sebaceous glands --> sebum) Aprocrine glands: apical surface is lost , milk glands

Question 45

Secretion types

Answer 45

Serous Gland ( watery solution has enzymes ( parotid gland) Mucous Gland (mucins that hydrate form mucus (sublingual gland) Mixed Exocrine Glands ( contain more than 1 gland cell type and can produce two different exocrine secretions. ( submandibular gland)