BL - Epithelial Tissues And Exocrine Glands Flashcards

1
Q

What do mucous membranes line?

A

Certain internal tubes which open to the interior, e.g. alimentary, respiratory, urinary

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2
Q

What does a mucous membrane consist of?

A

EPITHELIUM lining the lumen of a tube, layer of connective tissue called LAMINA PROPRIA, third layer of smooth muscle cells (only in alimentary tract) called MUSCULARIS MUCOSAE

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3
Q

What are serous membranes?

A

Thin, two-part membranes which line certain closed body cavities and envelope the viscera.

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4
Q

Why do serous membranes secrete fluid?

A

It promotes friction free movement of the structures the membrane surrounds.

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5
Q

What does the serous membrane consist of?

A

A SIMPLE SQUAMOUS EPITHELIUM which secretes fluid and a THIN LAYER OF CONNECTIVE TISSUE which attaches the epithelium to adjacent tissues.

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6
Q

Do serous membranes completely enclose the organs?

A

No - the organs are surrounded by the membrane but not completely enveloped.

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7
Q

Which is the outer side of the serosa - visceral or parietal?

A

Parietal is outside, visceral is inside.

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8
Q

What are epithelia?

A

Sheets of contiguous cells, of varied embryonic origin, that cover the external surface of the body and line internal surfaces.

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9
Q

Give an example of an exterior surface with an epithelial lining.

A

Skin

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10
Q

Give an example of an interior space that opens to the exterior which has an epithelial lining.

A

Gastrointestinal tract, respiratory tract, genitourinary tract.

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11
Q

Give an example of an interior space which does not open to the exterior which has an epithelial lining.

A

Pericardial sac, pleural sacs, peritoneum, blood vessels, lymphatic vessels

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12
Q

What is the basement membrane?

A

Thin, flexible, acellular layer which lies between epithelial cells and connective tissue.

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13
Q

What does the basement membrane do?

A

It serves as a strong, flexible layer to which epithelial cells adhere, and a cellular/molecular filter.

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14
Q

What does the basement membrane consist of?

A

Basal lamina laid down by epithelial cells, which is augmented by a variably thick layer of reticular fibrils.

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15
Q

Give a location where a simple squamous epithelium could be found.

A

Lining of blood and lymph vessels, lining of body cavities, gas exchange epithelium

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16
Q

Give some functions of the simple squamous epithelium.

A

Lubrication, gas exchange, barrier, active transport

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17
Q

Give some locations of the simple cuboidal epithelium.

A

Thyroid follicles, small ducts of exocrine glands,

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18
Q

Give some functions of the simple cuboidal epithelium.

A

Absorption and conduit, secretion

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19
Q

Give some locations of the simple columnar epithelium.

A

Stomach lining and gastric gland, small intestine and colon.

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20
Q

Give some functions of the simple columnar epithelium.

A

Absorption, secretion, lubrication, transport.

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21
Q

What is the difference between simple and stratified epithelia?

A

Simple has one layer of cells while stratified has many layers. Pseudostratified has one layer but appears to have many.

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22
Q

Give a location of pseudostratified epithelia.

A

Lining of nasal cavity, trachea and bronchi.

23
Q

Give a function of pseudostratified epithelia.

A

Secretion and conduit, absorption

24
Q

Give a location of a stratified squamous non-keratinised epithelium.

A

Oral cavity, oesophagus, larynx.

25
Q

Give a function of stratified squamous non-keratinised epithelia.

A

Protection against abrasion, reduced water loss while remaining moist.

26
Q

Why does the epidermis of the skin have no blood supply?

A

Nutrients can diffuse directly into it.

27
Q

What are the four layers of the epidermis?

A

Horny layer, granular layer, prickle cell layer, basal layer.

28
Q

Which layer of the epithelium does keratinocyte mitosis occur in?

A

The basal layer.

29
Q

How is the keratin found in the epidermis formed?

A

Keratinocytes are formed in the basal layer, then move upwards to form the prickle cell layer. They lose the ability to divide here. Keratinocytes synthesise keratins (fibrous proteins).

30
Q

What happens to keratinocytes in the granular layer?

A

They lose their plasma membrane and begin differentiating into corneocytes (main cells of stratum corneum).

31
Q

What are keratohyalin granules made of?

A

Keratins, other fibrous proteins, enzymes

32
Q

Give two examples of cross-link proteins found in the granular layer.

A

Fillaggrin (aggregates keratins), involucrin (corneocyte envelope).

33
Q

What is the stratum corneum (horny layer) made up of?

A

Layers of flattened corneocytes. It has a major role in skin barrier function.

34
Q

What is the transit time of a keratinocyte from the basal layer to the stratum corneum?

A

28-40 days.

35
Q

What are melanocytes?

A

Dendritic cells of neural crest origin which occur at intervals along the basal layer of the epidermis.

36
Q

What do melanocytes do?

A

They produce melanin, the main main pigment that gives the skin its colour.

37
Q

What are Langerhans cells?

A

Dendritic cells of bone marrow origin scattered throughout the prickle cell layer.

38
Q

What do Langerhans cells do?

A

They have a highly specialised capacity to present antigens to T lymphocytes. They also mediate immune reactions.

39
Q

Give some examples of where you would find stratified squamous keratinised epithelium?

A

Surface of skin and some in oral cavity.

40
Q

What are the functions of stratified squamous epithelia?

A

Protection against abrasion and physical trauma, prevention of water loss and microbial invasion, shields against UV light damage.

41
Q

What shape are cells in the transitional epithelium?

A

They vary in shape from columnar/cuboidal to flattened.

42
Q

Give some locations of transitional epithelium.

A

Renal calyces, ureters, bladder, urethra.

43
Q

Give some functions of transitional epithelium.

A

Distensibility, protection of underlying tissues from toxic chemicals.

44
Q

What is a gland?

A

An epithelial cell or collection of cells specialised for secretion.

45
Q

What is the difference between an endocrine and exocrine gland?

A
Exocrine = a gland with ducts.
Endocrine = a gland which secretes directly into the bloodstream ("ductless")
46
Q

Give an example of a unicellular exocrine gland.

A

A goblet cell.

47
Q

What is meconium ileus?

A

An inability to pass the first faeces, often occurs in newborns with CF.

48
Q

What is an acinus?

A

The secretory unit of many exocrine glands.

49
Q

Name the five different structures of simple glands.

A

Simple tubular, simple coiled tubular, simple branched tubular, simple alveolar, simple branched alveolar.

50
Q

What is merocrine secretion?

A

Exocytosis - the vast majority of glands function this way.

51
Q

What is apocrine synthesis?

A

Secreted droplets covered by plasmalemma, eg fat droplets in milk.

52
Q

What is holocrine secretion?

A

The whole cell breaks down, eg sebaceous gland of skin.

53
Q

Why does the exocrine pancreas often become inflamed in people with cystic fibrosis?

A

The secretions contain too little water and become thickened, resulting in the ducts becoming blocked.