Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

ANAT 400 - Embryology > Skin, Hair, and Nails > Flashcards

Skin, Hair, and Nails Flashcards

1
Q

Label the skin

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

What are the four layers of the epidermis? (top to bottom)

A
  • Horny cell layer
  • Granular cell layer
  • Spinous layer
  • Basal layer
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Describe each of the four layers of the epidermis:

  • Horny cell layer
  • Granular cell layer
  • Spinous layer
  • Basal layer
A
  • Horny cell layer
    • Cells have lost all organelles, no metabolic activity - dead cells (sacs filled w/ keratin)
  • Granular cell layer
    • Cells flatten, organelles begin degenerating, protein granules
  • Spinous layer
    • Cells start making keratin
    • Stuck together with desmosome adhesions between spinous cells
  • Basal layer
    • Dividing cells
    • Stem cell layer (1-cell thick)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Epidermis is a ________, _______ epithelium with _____ main layers

A

Epidermis is a multilayered, stratified epithelium with 4 main layers

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

Epidermis is derived from:

A

Ectoderm

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

Epidermis starts as:

While it develops it is covered by a ______

A

Epidermis starts as: the single-cell layer of ectoderm → gives rise to epidermis

While it develops it is covered by a temporary protective coat: Periderm

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

How is the periderm formed?

A

Periderm is temporary protective coat that covers the developing epidermis.

Ectoderm gives rise to a new layer of squamous epithelium - the periderm

layer under is the basal layer

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

Label the skin at 4, 7, 11 weeks and at birth

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

Periderm is maintained until _____ at which point the _____ has developed and the periderm is ______

A

Periderm is maintained until mid-pregnancy at which point the horny/cornified layer has developed and the periderm is sloughed off

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

What are two functions of the periderm

A
  • Protective barrier from amniotic fluid
  • Prevents adhesion of adjacent epithelia

Loss of periderm is associated with severe congenital malformations

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

The periderm is shed at ~____ week. If not shed, called a ______ baby

A

The periderm is shed at ~21 week. If not shed, called a colloidon baby

  • usually associated with a skin disorder
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is vernix caseosa?

A
  • means “cheese varnish”
  • Shed periderm cells and fatty secretions from sebaceous glands produce the vernix caseoso covering newborns
  • Protects developing fetal skin from amniotic fluid in utero
    • different theories on function post-natally (some believe should be left to absorb rather than bathed off)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Shed periderm cells and fatty secretions from sebaceous glands produce the ____________ covering newborns

A

Shed periderm cells and fatty secretions from sebaceous glands produce the vernix caseoso covering newborns

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

Function of the vernix caseosa?

A
  • Protects developing fetal skin from amniotic fluid in utero
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Epidermal ridges form through _________

A

Epidermal ridges form through proliferation of basal cells

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

Epidermal ridges form through proliferation of basal cells

  • Downward growth of epidermal ridges forms ________
A

Epidermal ridges form through proliferation of basal cells

  • Downward growth of epidermal ridges forms dermal papillae
    • interdigitations that links dermis and epidermis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q
  • What forms in the dermal papillae?
A

Capillary loops and sensory nerve endings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q
  • _________ form through proliferation of basal cells
  • ________ forms dermal papillae
A
  • Epidermal ridges form through the proliferation of basal cells
  • Downward growth of epidermal ridges forms dermal papillae
    • interdigitations that links dermis and epidermis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Dermis on the back is formed by _______

Dermis elsewhere on the torso and limbs is formed by _______

Head dermis is from ________

A

Dermis on the back is formed by Dermatome (from somites spitting into dermamyotome and sclerotome; dermamyotome differentiates into dermatome and myotome)

Dermis elsewhere on the torso and limbs is formed by somatic lateral plate mesoderm

Head dermis is from Neural crest cells

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

What is Ichthyosis? Cause?

A
  • Family of skin disorders categorized by dry, cracked, scaly skin
  • Caused by genetic defect that impairs skin barrier function
    • Epidermal cells hyperproliferate and/or become overly adherent and don’t shed properly - causing scalty appearance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are ectodermal appendages? (5)

A

Growths off developing skin that have epidermal contributions

  • Hair
  • Sweat glands
  • Nails
  • Mammary Glands
  • teeth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Ectodermal appendages follow the same pattern of development initially:

  • formation of ______
  • Formation of _____
  • _______
A

Ectodermal appendages follow the same pattern of development initially:

  • formation of placode (ectodermal placode)
    • localized thickening of ectoderm → bulge into underlying mesenchyme
  • Formation of ectodermal bud
    • _extension into mesenchyme (_mesoderm in body; neural crest in head)
  • Morphogenesis
    • Shaping
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

How does the ectodermal placode grow?

A

Grows via cell migration - not proliferation

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

What is the ectodermal placode?

A
  • local thickening of ectodermal epithelium
  • Stratified
  • Results from cell migration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
The _______ generates hair and extends through epidermis into dermis
The _hair follicle_ generates hair and extends through epidermis into dermis
26
Label the hair follicle and surrounding structures
27
The dermal papilla originates from \_\_\_\_\_
The dermal papilla originates from _mesenchyme_ (origin from mesoderm or neural crest cells in head)
28
Blood vessels and nerves enter the hair follicle through the \_\_\_\_\_\_\_
Blood vessels and nerves enter the hair follicle through the _dermal papilla_
29
What is the germinal matrix?
Stem cells in the hair follicle Divide and add cells (keratinocytes which mature → dead cells) to the root → lengthens
30
What are the four stages of hair follicle development?
1. Placode 2. Hair germ 3. Hair peg 4. Mature follicle
31
The ________ doesn't contribute cells to the hair. It induces formation of the germinal matrix and maintains it
The _dermal papilla_ doesn't contribute cells to the hair. It induces formation of the germinal matrix and maintains it
32
Role of the Dermal papilla in hair follicle development?
The _dermal papilla_ doesn't contribute cells to the hair. It induces formation of the germinal matrix and maintains it
33
In both the placode stage and the hair germ stage (of hair follicle development), what is present?
Dermal condensate → becomes the dermal papilla
34
What is the hair peg stage of hair follicle development?
Mesenchymal cells are condensed into an invagination of hair peg → papilla Papilla sits directly under stem cells and acts as a signalling centre to maintain stem cells
35
Label the stages of hair follicle development
36
Melanocytes sit just above the ______ in the hair follicle. They arise from \_\_\_\_\_\_\_, invade the follicle and \_\_\_\_\_\_\_
Melanocytes sit just above the _dermal papilla, by the germ matrix_ in the hair follicle. They arise from _neural crest_, invade the follicle and _contribute pigment to the hair_
37
What is notable about hair follicle arrangement?
* There is a regular arrangement of follicles all facing same direction * Signaling mechanisms regulate location and direction * PLANAR CELL POLARITY
38
What is lanugo?
First hairs that start forming at week 12 - very soft
39
Function of lanugo?
* lanugo: first, soft hairs forming at week 12 * Helps trap the vernix caseosa (cheesy layer - protect skin in utero)
40
How does hair change after birth?
Lanugo (first hairs) are replaced mostly by Vellus hair (stronger, finer, less pigmented (all over body)) Lanugo on head is replaced by darker, thicker **terminal hair**
41
What happens to hair at puberty?
Hair in select regions switches from vellus to terminal
42
How are new hair follicles added post-natally?
They aren't. We are born with ~5 million hair follicles and no new ones are added
43
What are the four phases of the hair cycle?
* Growth * Regression * Rest * Renewal
44
The _____ muscles are around the base of the hair follicle and cause the hair to stand erect (goosebumps)
The _Arrector pili_ muscles are around the base of the hair follicle and cause the hair to stand erect (goosebumps)
45
Arrector pili muscles are ________ derived from the \_\_\_\_\_\_\_
Arrector pili muscles are _smooth muscle_ derived from the _mesenchyme (mesodermal derived)_
46
Sebaceous glands are ______ derivatives that protrude off the \_\_\_\_\_\_
Sebaceous glands are _ectodermal_ derivatives that protrude off the _hair follicle_
47
Sebaceous glands produce _____ through a ______ mechanism
Sebaceous glands produce _oily secretion_ through a _holocrine_ mechanism * build up substance within the cell then whole cell is shed and breaks down to release oily secretion
48
Sebaceous glands produce _____ through a ______ mechanism
Sebaceous glands produce _oily secretion_ through a _holocrine_ mechanism (do not have a lumen) * build up substance within the cell then whole cell is shed and breaks down to release oily secretion
49
Sebaceous glands form \_\_\_\_\_\_\_. Central cells of the gland continually ______ to produce ______ to protect the skin from friction and dehydration
Sebaceous glands form _as extension of hair follicle_. Central cells of the gland continually _breakdown_ to produce _oily secretion (sebum)_ to protect the skin from friction and dehydration
50
Eccrine sweat glands develop from \_\_\_\_\_\_\_
Eccrine sweat glands develop from _separate ectoderm placode (not associated with hair follicle)_
51
Eccrine sweat glands: * extensions of \_\_\_\_\_\_ * ________ to make lumen * ectodermal cells develop into \_\_\_\_\_\_\_ * Surrounding mesenchymal cells become \_\_\_\_\_\_\_
Eccrine sweat glands: * extensions of _epidermal cells into dermis_ * _central cells degenerate_ to make lumen * ectodermal cells develop into _secretory cells_ * Surrounding mesenchymal cells become _smooth muscle_
52
Eccrine sweat glands: * extensions of epidermal cells into dermis * central cells degenerate to make \_\_\_\_\_\_ * ________ develop into secretory cells * Surrounding _________ become smooth muscle
Eccrine sweat glands: * extensions of epidermal cells into dermis * central cells degenerate to make _lumen_ * _ectodermal_ cells develop into secretory cells * Surrounding _mesenchymal_ cells become smooth muscle
53
1. How do mammary glands develop?
* Two lines of ectodermal thickening appear on the ventral side of the body * In humans, the ridges disappear and just *one site* on each side gives rise to **primary mammary gland**
54
Mammary gland development: 1 * Two lines of ________ appear on the ________ side of the body * In humans, the ridges disappear and just *one site* on each side gives rise to **\_\_\_\_\_\_\_\_**
Mammary gland development: * Two lines of ectodermal thickening appear on the ventral side of the body * In humans, the ridges disappear and just *one site* on each side gives rise to **primary mammary gland**
55
Mammary gland development 2 * _____ branches into _______ which becomes the \_\_\_\_\_\_\_\_ * ______ prenatally in response to placental hormones * After birth: * _______ around surface opening (\_\_\_\_\_\_\_) proliferates to form areola and nipple * _____ will form the smooth muscle around nipple and ducts
Mammary gland development 2 * Primary bud branches into _secondary buds_ which becomes the lactiferous ducts * Canalize prenatally in response to placental hormones * form lumen * After birth: * Connective tissue around surface opening (mammary pit) proliferates to form areola and nipple * Mesenchyme will form the smooth muscle around nipple and ducts
56
Mammary gland: \_\_\_\_\_\_\_\_\_ makes support cells \_\_\_\_\_\_\_\_\_ makes lining and functional (secretory cells)
Mammary gland: _mesodermal-derived mesenchyme_ makes support cells _endoderm_ makes lining and functional (secretory cells)
57
Breasts of neonates contain _____ but not \_\_\_\_\_\_
Breasts of neonates contain _ducts_ but not _alveoli (secretory sacs)_
58
What part of the breast forms at puberty in females?
The alveoli (secretory sacs) * primary source of milk * Allow milk to be held and secreted
59
What is witches' milk?
Neonatal ductal cells do have some ability to make milk, which may happen in response to maternal hormones (lasts \<1 week)
60
Crown of the tooth is covered in _____ while root is covered in \_\_\_\_\_\_- \_\_\_\_\_\_ forms the middle layer \_\_\_\_\_ forms the inner part of the tooth
Crown of the tooth is covered in _enamel_ while root is covered in _softer cementum_ _dentin_ forms the middle layer _pulp_ forms the inner part of the tooth
61
Label the tooth anatomy
62
\_\_\_\_\_\_ is \>90% inorganic, very hard but also brittle
_enamel_ is \>90% inorganic, very hard but also brittle
63
\_\_\_\_\_\_\_ is avascular/acellular and cannot be renewed
enamel is avascular/acellular and cannot be renewed
64
\_\_\_\_\_\_ is 45% inorganic, softer but less brittle than enamel
_Dentin_ is 45% inorganic, softer but less brittle than enamel
65
\_\_\_\_\_\_ line outer wall of pulp chamber and add dentin throughout life so pulp chamber shrinks
_Odontoblasts_ line outer wall of pulp chamber and add dentin throughout life so pulp chamber shrinks
66
What cells make dentin?
Odontoblasts
67
What are the four stages of tooth development?
* Placode * Bud * Cap * Bell
68
What is the enamel knot and where is it found?
Enamel knot is a cluster of ectodermal cells sitting just above the dental papilla
69
During which stage does the enamel knot arise?
Arises during the cap stage and is an important signaling center for tooth development. In molars, secondary enamel knots develop - **one for each cusp**
70
Function of enamel knot?
Important signaling centre for tooth development * one for each cusp
71
In tooth development, the placode grows into mesenchyme which is derived from \_\_\_\_\_\_
In tooth development, the placode grows into mesenchyme which is derived from _Neural crest cells (head and neck)_
72
What is the dental papilla?
Invagination of mesenchymeinto placode
73
What stages of tooth formation are shown in the image?
74
What stages of tooth formation are shown in the image?
75
Label
76
What is the enamel reticulum?
Connective tissue network that forms during tooth development
77
Label the bell stage
78
What two cell types differentiate in the bell stage and where does this differentiation start?
* Ameloblasts * Odontoblasts Differentiation starts at cusps and spreads down both sides
79
What induces odontoblast differentiation? What induces ameloblast differentiation?
* Odontoblasts: * Signals from enamel knot induce odontoblast differentiation from ectoderm * Ameloblasts: * Basal membrane breaks down, so two cell layers are intact * Odontoblasts induce ameloblast differentiation from neural crest
80
* Odontoblasts: * Signals from _______ induce odontoblast differentiation from \_\_\_\_\_\_ * Ameloblasts: * ______ breaks down, so two cell layers are intact * ______ induce ameloblast differentiation from \_\_\_\_\_\_
* Odontoblasts: * Signals from enamel knot induce odontoblast differentiation from ectoderm * Ameloblasts: * Basal membrane breaks down, so two cell layers are intact * Odontoblasts induce ameloblast differentiation from neural crest
81
Odontoblasts secrete ______ creating \_\_\_\_\_
Odontoblasts secrete _pre-dentin_ creating _separation between cell layers_
82
Odontoblasts leave behind ______ which also secretes components of pre-dentin
Odontoblasts leave behind _processes (in pre-dentin)_ which also secretes components of pre-dentin
83
Ameloblasts secrete \_\_\_\_\_\_
Ameloblasts secrete _pre-enamel_
84
Label the developing tooth
85
label the developing tooth
86
Function of OEE (outer enamel epithelium)
OEE supports enamel development and tooth eruption but is subsequently lost
87
What is important about the fold of inner enamel epithelium and outer enamel epithelium (IEE/OEE)
The fold of inner enamel epithelium and outer enamel epithelium (IEE/OEE) **will expand to establish the _root of the tooth_**
88
What is the dental lamina and what is its function?
Dental lamina: * Ectodermal extension * Temporarily connecting developing tooth to surface ectoderm * eventually degenerates
89
Bud for permanent tooth develops as extension off \_\_\_\_\_\_
Bud for permanent tooth develops as extension off _dental lamina_
90
Why might the following dental abnormalities arise?
* demonstrate the importance of **patterning** * signalling mechanisms that control where teeth form (Morphogen signaling)

ANAT 400 - Embryology (14 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions