Brainscape's Knowledge GenomeTM

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


See full index

General - Histology 🔬 > L8: Skin > Flashcards

L8: Skin Flashcards

1
Q

What are the types of skin?

A

❖ Thick (non-hairy) skin: found in palms and soles.
❖ Thin (hairy) skin: covers the rest of the body.

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

What are the layers of skin?

A

❖ Epidermis: Stratified squamous keratinized epithelium.

❖ Dermis: Connective tissue.

N.B: The hypodermis is the subcutaneous adipose tissue (It is not a part of the skin).

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

What is the structure of thin skin?

A

formed of two layers

1) Epidermis: Contains 4 types of cells: (KM”L)
 keratinocytes (85% of cells).
 Langerhans cells.
 Melanocytes.
 Merkel cells.

2) Dermis: (PR)
 Papillary layer
 Reticular layer

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

How many layers are keratinocytes arranged in?

A

4

Malpighian layer (2 layers) - stratum basale and stratum spinosum

Granular layer (Skin Barrier layer) - stratum granulosom

Clear layer - stratum lucidum

Horny cell layer - stratum corneum

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

Characters of the basal cell layer in the skin

A

S: Single layer of columnar cells.
N: Nucleus: basal & oval.
C: Cytoplasm: deep basophilic& (due to ribosomes).
E: By EM: It contains prekeratin filaments.
F: Function: Responsible for regeneration of keratinocytes so it shows mitotic figures.

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

Characters of a prickle cell layer in the skin

A

L: L/M: Formed of 4-8 cell layers.
S: Shape: polyhedral.
N: Nuclei: Central and rounded.
C: Cytoplasm: pale basophilic.
E: EM: The cells are connected by cytoplasmic processes. (Desmosome)

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

Characters of the granular layer in the skin

A

S: Shape: 2- 4 layers of flattened, diamond-shaped cells.

N: nuclei: flat & central.

C: Cytoplasm: has basophilic Keratohyaline-granules.

E: EM: The cytoplasm contains “lamellar granules”, which
contain phospholipids

F: Function: The granules are released in the intercellular
space to act as skin barrier because they are:
 waterproofing skin.
 preventing foreign bodies from penetrating the skin.

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

What are the characteristics of the clear layer of the skin?

A

 It appears as a (CHAT W) thin, wavy, clear, homogenous acidophilic line.

 It is formed of dead non-nucleated flattened cells, “scales” which contain “eleidin granules” (derivative of kerato- hyaline granules).

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

What are the characteristics of the horny cell layer in the skin?

A

 It consists of several layers of (AHS) acidophilic horny scales called “squames”

 The scales contain soft keratin (derived from eleidin).

 The squames are continuously shed or sloughed from the surface and continuously replaced by new ones from the deeper cells.

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

What is the site of melanocytes?

A

between the cells of the basal layer of the epidermis.

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

What is the LM of melanocytes?

A

S: shape: branched cells with rounded cell bodies

N: Nucleus: rounded and central

C: Cytoplasm: contains melanin pigment (brown to black
pigment, responsible for pigmentation of the skin).

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

What is the function of melanocytes?

A

synthesis of melanin

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

What are the clinical applications of melanocytes?

A

Albinism

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

What is albinism and what is its cause?

A
  • an inherited disease characterized by white hair and very light-colored skin.
  • Cause: Albinism is caused by a mutation in genes responsible for melanin formation.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the site of langerhans cells ?

A

upper layers of Spinouts layer.

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

What is the origin of Langerhans cells?

A

blood monocytes.

17
Q

What is the LM on Langerhans cells?

A

S: Shape: branched.
N: Nucleus: central.
C: Contain Birbeck granules.

Stained with silver& vital stains.

18
Q

What is the function of Langerhans cells?

A

Phagocytic& antigen-presenting cells (APC).

19
Q

What is the site of Merkels cells?

A

Basal cell layer of epidermis.

20
Q

What is the function of Merkels cells?

A

Receptors for touch sensation.

21
Q

Compare between the papillary layer and the reticular layer of the dermis

A
22
Q

What are the histological differences between thin and thick skin?

A
23
Q

What are skin related structures?

A

❖ They include:

 Sweat glands.
 Hair& hair follicle.
 Sebaceous glands.
 Arrector pili muscle.

24
Q

What is the site of sweat glands?

A

deep in the dermis or the hypodermis.

25
Q

What is the number of sweat glands?

A

more numerous in the thick skin than in the thin skin.

26
Q

What are the types of sweat glands? And compare between them.

A
27
Q

What is the structure of sweat glands?

A

1) The secretory parts (acini)

2) The Excretory parts (ducts)
- Duct collects sweat secretion from the acini

  • In merocrine glands: duct ascends in a spiral course to the epidermis
  • It opens on the surface of the skin.
28
Q

What does the hair consist of (by naked eye)?

A

Shaft: projecting above skin surface.

Root: embedded or implanted in the skin.

Hair bulb:
• the expanded lower end of the hair.

• It consists of (hair matrix) which is a cellular mass.

• Proliferation of the matrix cells results in growth of the hair in length.

29
Q

What does the shaft of the root of the hair consist of?

A

Medulla: It contains soft keratin.

Cortex: It contains hard keratin and melanin pigments which give the color of the hair.

Cuticle: It contains hard keratin.

30
Q

What is the definition of hair follicles?

A

It is a hole formed by an epidermal down-growth in which the root of the hair is present.

31
Q

What is the structure of hair follicles?

A

The wall of the hair follicle is called (root sheath) which is divided into 3 types:

Inner root sheath: ————

Outer root sheath: It is identical with the malpighian layer of the epidermis.

CT Sheath: It is a condensed part of C. T. of the dermis.

32
Q

What is the site of sebaceous glands?

A

They open into the upper 1/3 of the hair follicle at the obtuse angle between the follicle and the surface of the skin

33
Q

What is the mood of secretion of Sebaceous glands?

A

Holocrine

i.e. the central cells disintegrate completely to secrete (sebum).

34
Q

What is the mood of secretion of Sebaceous glands?

A

Holocrine

i.e. the central cells disintegrate completely to secrete (sebum).

35
Q

What is the structure of sebaceous glands?

A
  • Secretory part: It is a sac-like structure i.e formed of one or more alveoli which open into a common duct.
  • Excretory duct: Short, wide and opens into the upper 1/3 of the hair follicle, Lined with stratified squamous epithelium.
36
Q

What is the definition of arrector pili muscles?

A

❖ It is a band of smooth muscle fibers touching the bottom of the sebaceous gland.

37
Q

What is the function of the arrector pili muscles?

A

❖ Contraction of this muscle due to stress or emotion (as fear) leads to:

 Erection of the hair shaft.

 Appearance of goose-skin.

 Squeezing of sebaceous secretion into the duct

General - Histology 🔬 (8 decks)

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