Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

A&P > Week 2- Epithelial Tissue > Flashcards

Week 2- Epithelial Tissue Flashcards

1
Q

Epithelial Tissue aka Epithelium

A

-Composed of one or more layers of closely packed cells
-Contains little to no extracellular matrix between these cells
-covers body surfaces, lines the body and organ cavities, and forms glands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Common Characteristics

A

1) Cellularity
2) Polarity
3) Attachment to basement membrane
4) Avascularity
5) Extensive innervation
6) High regeneration capacity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Cellularity

A

-Epithelial tissue is composed almost entirely of tightly packed cells
-There is a minimal amount of extracellular matrix between cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Polarity

A

Epithelium has an apical and basal surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Apical surface

A

-Exposed either to the external environment or to some internal body space
-Can have either microvilli or cilia
-Lateral surfaces may contain membrane (intercellular) junctions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Microvilli

A

-Small membranous projections on apical surface of the cell that increase its surface area for secretion and absorption
-Individual microvilli can’t be distinguished with light microscopy, rather they appear collectively as a brush border

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Cilia

A

Numerous, slightly longer, membranous projections that move fluid, mucus, and materials past the cell surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Basal surface

A

-a fixed or deep surface
-Epithelium is attached to a basement membrane with underlying connective tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Basement membrane

A

-Binds basal surface of epithelial layer
-Consists of 3 molecular levels that can be viewed under electron microscope (using a light microscope, it appears as a single noncellular/molecular layer)
-These molecular layers are formed by secretions of both the epithelium and the underlying connective tissue
-Composed of collagen, glycoproteins, and proteoglycans
-Molecular structures of membrane act like glue to strengthen attachment and form a selective molecular barrier between the epithelium and underlying connective tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Avascularity

A

-All epithelial tissues lack blood vessels
-Get nutrients either directly across apical surface or by diffusion across the basal surface from blood vessels within underlying connective tissue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Extensive innervation

A

Richly innervated (supplied with nerves) to detect changes in the environment at that body or organ region

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

High regeneration capacity

A

-Undergo cell division frequently
-Allows tissue to regenerate at high rate, a necessary condition for a tissue that is often exposed to the environment and lost by abrasion and damage
-Continual replacement occurs through cell division of the deepest epithelial cells (stem cells), which are adjacent to basement membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Functions of Epithelial Tissue

A

1) Physical protection
2) Selective permeability
3) Secretions
4) Sensations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Physical protection

A

Protects both external and internal surfaces from dehydration, abrasion, and destruction by physical, chemical, or biological agents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Selective permeability

A

-Exhibits range of permeabilty
-May be relatively non-permeable to some substances, while promoting/assisting passage of other ions/molecules
-All substances entering and leaving the body must pass through epithelium
-Acts as body’s gatekeepers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Secretions

A

-Some are specialized to produce and release secretion
-These cells form glands
-Glands may be individual cells scattered among other cell types in an epithelium (ex: goblet cells) or arranged in small, organized clusters within a multicellular gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Sensations

A

-Innervated by sensory nerve endings to detect or respond to a stimulus
-These nerve endings and those in underlying connective tissue continuously relay sensory input to CNS concerning touch, pressure, temp, and pain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the two things used to classify epithelial tissue types?

A

1) Number of cell layers
2) Shape of cells at apical surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Simple epithelium

A

-One layer of cells
-All cells are in direct contact with basement membrane
-Found in areas where stress in minimal and secretion, absorption, or filtrations is primary function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Stratified epithelium

A

-Contains 2 or more layers of cells
-Only cells in basal (deepest) layer are in contact with basement membrane
-Provides either more structural support or better protection for underlying tissue
-Cells in basal layer are continuously regenerated as cells in the apical layer are lost due to abrasion or stress

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Pseudostratifed epithelium

A

-Appears layered because cells’ nuclei are distributed at different levels between apical and basal surfaces
-All cells are attached to basement membrane, but some of them do not reach its apical surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Squamous Cells

A

-Flat, wide, and somewhat irregular in shape
-Cells are arranged like floor tiles, and nucleus is somewhat flattened

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Cuboidal Cells

A

-About as tall as they are wide
-Don’t resemble perfect cubes because edges are somewhat rounded
-Cells nucleus is spherical and located in center of cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Columnar cells

A

-Slender and taller than they are wide
-Nucleus is oval and usually oriented lengthwise and in the basal region

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Transitional cells

A

-Can readily change shape from polyhedral to more flattened, depending upon degree to which epithelium is stretched
-Shape change occurs when epithelium cycles between distended and relaxed states (such as lining of bladder, which fills with urine and is later emptied)

26
Q

Simple squamous epithelium

A

-Consists of single layer of flattened cells
-Extremely delicate and represents thinnest possible barrier to allow rapid movement of molecules and ions across epithelium by membrane transport process
-Forms lining of air sacs (alveoli) of lung
-well suited for exchange of O and CO2 between blood and inhaled air

27
Q

Endothelium

A

Name of the simple squamous epithelium that lines both blood vessels and lymph vessels

28
Q

Mesothelium

A

-Name given to simple squamous epithelium that forms serous membrane of body cavities
-Gets its name from the embryonic primary germ layer called mesoderm, from which it’s derived

29
Q

Simple cuboidal epithelium

A

-Contains one layer of uniformly shaped cells that are about as tall as they are wide with a centrally located, spherical nucleus
-Allows for both absorption and secretion
-Uniform shape makes them ideal to form structural components of glands
-Location: lining of kidney tubules, thyroid gland follicles, surface of ovary, and secretory regions and ducts of most exocrine glands

30
Q

Simple columnar epithelium

A

-Single layer of cells that are taller than they are wide
-Nucleus is oval, oriented lengthwise, and located in basal region
-Ideal for both absorptive and secretory functions
-2 types: ciliated and nonciliated

31
Q

Nonciliated simple columnar epithelium

A

-Often contains microvilli and a scattering of unicellular glands called goblet cells
-Goblet cells secrete mucin (a glycoprotein that when hydrated forms mucus)
-Lines most of GI tract from stomach to upper portion of anal canal

32
Q

Ciliated simple columnar epithelium

A

-Has cilia that project from apical surfaces of cells
-Mucus covers apical surface and moves by the beating of the cilia
-Goblet cells are interspersed throughout this epithelium
-Lines larger bronchioles in lung and uterine tubes (helps move oocyte from ovary to uterus)

33
Q

Pseudostratified columnar epithelium

A

-Not really stratified because all its cells are in direct contact with basement membrane, but nuclei are scattered at different distances from basal surface
-Not all cells reach apical surface
-Columnar cells always reach apical surface and shorted basal cells are stem cells that give rise to the columnar cells
-2 types: ciliated and nonciliated

34
Q

Pseudostratified ciliated columnar epithelium

A

-Contains cilia on apical surface
-Houses goblet cells that secrete mucin (hydrates to mucus which traps foreign particles and is moved by beating cilia)
-Lines larger air passageways of respiratory system (nasal cavity, part of pharynx, part of larynx, trachea, and bronchi)

35
Q

Pseudostratified nonciliated columnar epithelium

A

-Lacks goblet cells and cilia
-Rare and found primarily in membranous part of male urethra and epididymis

36
Q

Stratifed squamous epithelium

A

-Has multiple cell layers and only deepest layer is in direct contact with basement membrane
-Cells in basal layers have cuboidal/polyhedral shape vs apical cells have flattened, squamous shape
-Protects underlying tissues from damage caused by abrasion and friction
-Stem cells in basal layer continuously divide to produce a new stem cell and a committed cell that is gradually displaced toward surface to replace those cells that have been lost
-Exists in 2 form: keratinized and nonkeratinized

37
Q

Keratinized Stratified Squamous Epithelium

A

-Superficial layers are composed of cells that are dead
-Cells lack nuclei and all organelles
-Filled with protein keratin (tough, protective protein that strengthens tissue)
-Ex: Epidermis (outer layer) of skin

38
Q

Nonkeratinized Stratified Squamous Epithelium

A

-Lack keratin and remain alive
-Since cells are alive, nuclei is visible throughout tissue
-Kept moist with secretions like saliva or mucus
-Form surface of mucous membranes that line oral cavity, part of pharynx, part of larynx, esophagus, vagina, and anus

39
Q

Stratified Cuboidal Epithelium

A

-Contains 2 or more layers of cells and superficial cells tend to be cuboidal in shape
-Forms tubes and ducts
-Protection and secretion
-Forms walls of ducts of most exocrine glands (such as ducts of sweat glands in skin and periphery of ovarian follicles

40
Q

Stratified columnar epithelium

A

-Relatively rare in body
-2 or more layers of cells, but only cells at apical surface are columnar
-Protects and secretes
-Found in large salivary glands, conjunctiva covering the eye, and segment of male urethra

41
Q

Transitional epithelium

A

-Limited to urinary tract
-Varies in appearance depending upon whether it is in a relaxed state or distended state
-In relaxed state basal cells appear cuboidal or polyhedral and apical cells are large and rounded
-When it stretches, it thins and apical cells flatten and become almost squamous
-Some binucleated cells are present
-By being able to stretch, ensures urine does not seep into underlying tissues of these organs

42
Q

Glands

A

-Individual cells or multicellular organs composed mostly of epithelial tissue
-Secrete substances either for use elsewhere in body or for elimination from body
-Glandular secretions include mucin, ions, hormones, enzymes, urea, ect

43
Q

Endocrine glands

A

-Lack ducts and secrete their products (hormones) into the blood to be transported throughout body
-Ex: Thyroid and adrenal glands

44
Q

Hormones

A

Act as chemical messengers to influence cell communication

45
Q

Exocrine glands

A

-Originate from an invagination of epithelium that burrows into underlying connective tissue
-Maintain connection with epithelial surface through a duct
-Ex: sweat glands, mammary glands, and salivary glands

46
Q

Duct

A

Epithelium lined tube through which gland secretions are discharged onto epithelial surface

47
Q

Unicellular exocrine glands

A

-Do not contain duct
-Located close to surface of epithelium in which they reside
-Most common type is goblet cell (found in simple columnar and pseudostratified ciliated columnar)

48
Q

Multicellular exocrine glands

A

-Contain numerous cells that work together to produce a secretion
-Consists of acini and one or more smaller ducts (merge to form a larger duct that transports secretion to epithelial surface)
-Typically surrounded by fibrous capsule and extensions of capsule called septa partition gland into lobes

49
Q

Acini

A

Clusters of cells that produce a secretion

50
Q

Septa

A

Extensions of fibrous capsule that partition gland into lobes

51
Q

How are exocrine glands classified?

A

Anatomic form or method of secretion

52
Q

Simple glands

A

Have single unbranched duct

53
Q

Compound glands

A

Have branched ducts

54
Q

Tubular

A

Secretory portion and duct have same diameter

55
Q

Acinar

A

Secretory portion forms an expanded sac

56
Q

Tubuloacinar

A

Has both tubules and acini

57
Q

Different Classifications of Exocrine Glands

A

1) Simple tubular
2) Simple branched tubular
3) Simple coiled tubular
4) Simple acinar
5) Simple branched acinar
6) Compound tubular
7) Compound acinar
8) Compound tubuloacinar

58
Q

Merocrine glands

A

-Package secretions into secretory vesicles and release secretions by exocytosis
-Glandular cells remain intact and are not damaged by producing secretion
-Ex: lacrimal (tear) glands, salivary glands, sweat glands, exocrine glands of pancreas, and gastric glands of stomach

59
Q

Apocrine glands

A

-Produce secretory material where cell’s apical portion pinches off, releasing cytoplasmic content
-Afterwards, cell repairs itself in order to repeat secretory activity
-Ex: mammary glands and ceruminous glands of ear

60
Q

Holocrine glands

A

-Formed from cells that accumulate a product; entire cell then disintegrates
-Holocrine secretion: viscous mixture of cell fragments and product of cell produced prior to its disintegration
-Ruptured dead cells are continuously replaced by other epithelial cells undergoing cellular division
-Ex: Oil-producing (sebaceous) glands in skin

A&P (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions