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Comparative Vertebrate Histology > Integumentary > Flashcards

Integumentary Flashcards

1
Q

What are the three components of the integumentary system?

A

Skin
Hypodermis
Sub-organs/ Skin derivatives/ Cutaneous appendages.

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2
Q

What are the two layers of skin?

A

Epidermis
Dermis

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3
Q

What lies below the dermis?

A

Hypodermis (Rich in adipose.)

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4
Q

What are appendages of the skin derived from?

A

Develop from Epidermis, so derived Epithelially.

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5
Q

Primary function of the integumentary system?

A

Protection.

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6
Q

What are the four methods of protection of the integumentary system?

A

-Keratinization (Inhibits Dehydration/ Harder to penetrate)
-Barrier to pathogens
-Dermal Armor (Inhibits Organ Damage.)
-Pigments (Inhibits UV Radiation.)

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7
Q

The process of sensing outside information facilitated by the integumentary system?

A

Exteroception. (Pain, Temp, Touch, Pressure.)

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8
Q

What is the largest sense organ of the vertebrate body?

A

Skin.

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9
Q

Function of the integumentary system that allows the exchange of gasses.
What vertebrates is this most present in?

A

Respiration
Mostly present in Amphibians, some fish and reptiles which have very thin/ Few scales (Resp. Between).
(Cannot breathe through scales, or keratinization. )

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10
Q

What are excretions of the integumentary system?

A
  • CO2 (even true for some species which do not practice cutaneous respiration).
  • Ammonia (Many Fish)
  • Nitrogenous waste via sweat (Mammals.)
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11
Q

Four Examples of thermoregulation by the integumentary system?

A

-Cutaneous appendages such as fur/ feathers in endotherms.
-Hypodermis insulation.
-Vascularization (Vasoconstriction/ dilation.) Occurs in the dermis.
-Sweat evaporation.

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12
Q

Three examples of nourishment produced by the integumentary system?

A
  • Vitamin D through photic stimulation (7-Dehydrocholesterol + UVB= D3.)
  • Milk secretion for young (Mammals)
  • Nutritive Mucus secretion for young ( Some Fish)
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13
Q

In some marine reptiles and birds the integumentary system has appendage glands called salt glands which excrete excess salts such as chloride, NaCl & K, etc. This is done to maintain conservation of water and avoid stressing the kidneys. What basic function of the integument is this serving?

A

Homeostasis.
The salt content is a concern in these species due to over consumption nearby salt water.
(Fun Fact: Chondrichthyes have salt glands in their rectum/ anus.)
Think reptiles like sea turtles and birds such as pelicans.
(Bony fish and mammals do not have these. Osteichthyes use chloride cells and mammals such as whales have better kidney function/ organization.)

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14
Q

Keratinization of the epidermis is a component of many vertebrates and helps defend against dehydration. What basic function of the integument system does this assist with?

A

Homeostasis.
Recall that Protection from dehydration isn’t all that important in species that live in wet environments.

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15
Q

What is a vertebrates first line of defense against pathogens?

A

The skin of the integumentary system.
It is highly regenerative which assists in renewing protection.

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16
Q

What part of the integumentary system can help protect the organs?

A

Dermal armor.
Think Scales.

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17
Q

What is the function of color in the integumentary system?

A

The color can be protective/ Signaling, and also aids in defense against UV rays.

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18
Q

Dermal scales not only serve a protective purpose but also as reservoirs for calcium and phosphate. What basic function of the integument is this providing.

A

Homeostasis.
Balance of these minerals.

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19
Q

Some animals go through a type of torpor/ dormancy during a hot/ dry period of the season, this is called aestivation. What is an adaptation of the integumentary system that allows homeostasis of hydration?

A

The posterior pituitary glands influences the integumentary system of these species to be able to absorb water from its surroundings such as mud.

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20
Q

What are four adaptations of the integumentary that assist with locomotion?

A
  • Claws.
  • Pads.
  • Scutes (Turtle shell/ Alligator Back plates.)
  • Feathers.
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21
Q

What are 2 ways the integument contributes to a vertebrates ability to communicate?

A
  • Excretions of pheromones.
  • Coloration.
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22
Q

Name for the transitions zones where the integumentary system is continuous with inner mucous membranes?

A

Mucocutaneous Junctions.

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23
Q

What are the macrophages of the integumentary system called?
How do they function?

A

Langerhans Cells.
They act as Dendritic/ Presenter cells to sensitize Lymphocytes against pathogens.
They can also Phagocytize pathogens.
(Think cat which brings its dead prey to show its owner.)

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24
Q

What is usually the epithelium of the epidermis?

A

Stratified squamous.
Mucus or keratinized.
Aquatic vertebrates may also have mucous layer to decrease friction- produced by glands.

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25
Q

2 Appendages produced when the epidermis invaginates down into the dermis or hypodermis?

A

Glands or Follicles- Epitheliul origin.

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26
Q

What layer of the skin?
- Tightly packed cells
- Avascular
- Highly Regenerative.
- Many intercellular junctions.

A

Epidermis.

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27
Q

What are the four cell types of the epidermis in mammals?

A
  • Keratinocytes (Most abundant in keratinized.)
  • Melanocytes
  • Langerhans Cells
  • Merkel Cells
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28
Q

Pigmentary system AKA:

A

Melanocyte System.

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29
Q

Reticuloendothelial System AKA:

A

Langerhans System.

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30
Q

Keratinizing System AKA:

A

Malpighian System.

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31
Q

Cellular system primarily located within the epidermis that relays “Touch” related information to the nearby innervation?

A

Merkel Cell System
Located Primarily in Stratum Basale.

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32
Q

What are the four systems which make up the epidermis?

A
  • Langerhans/ Reticuloendothelial System
  • Merkel Cell System
  • Pigmenary/ Melanocyte System.
  • Malpighian/ Keratinizing System.
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33
Q

How does the epidermis receive nutrients from the body?

A

By Diffusion
No Vascularization and in keratinized the top layers are already dead.

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34
Q

Where does the majority of integumentary innervation occur?

A

The Dermis.

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35
Q

What are the 4 (5) layers of the epidermis epithelium from superficial to deep?

A
  • Stratum Corneum.
    -Stratum Lucidum (Thick Skin ONLY)
  • Stratum Granulosum.
  • Stratum Spinosum.
  • Stratum Basale.
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36
Q

What are the three layers of Stratum Malpighi?

A

The Living Layers:
- Stratum Granulosum.
- Stratum Spinosum.
- Stratum Basale.

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37
Q

What is special about the epidermis of thick skin?
Where is thick skin commonly found?

A

It has two layers within the stratum Corneum:
- Stratum Corneum Proper.
- Stratum Lucidum (Not present in thin skin)
Commonly found on the pads of feet and hands.
(Exception!: Avian keratinized feet.)

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38
Q

This layer of the epidermis Rests on the basement membrane.
What type & shape of cells?
Activity/ Function?

A

Stratum Basale:
- Cuboidal/ Columnar shaped cells
- Source of stem cells for keratinocytes, so lots of mitotic activity.

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39
Q

This layer of the epidermis is where keratinization begins.
What type & shape of cells?
Activity/ Function?

A

Stratum Granulosum:
Layers of flattened cells
The cells have lamellated (Overlayed) granules of keratohyaline ( a Protein).
Greatest rate of keratin deposition.
Mitotic activity ends at this layer’s start, but still living cells.
Main cell Type: Keratinocyte.
(Uncommon, but not impossible to have normal isolates of langerhans & Merkel cells)

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40
Q

This layer of the epidermis is composed of polyhedral cells, and displays some mitotic activity.

A

Stratum Spinosum
This layer also has a negligible amount of keratinization.

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41
Q

What is the difference between stratum corneum and stratum corneum proper?

A

Stratum Corneum may also contain stratum lucidum when applicable (Thick Skin)
Stratum Corneum Proper does not.

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42
Q

This layer of the epidermis is composed of layers of dead stratified squamous epithelium, What is the stratum within this layer with a translucent appearance?

A

Stratum Lucidum

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43
Q

What are the two types of keratin which can be found within a keratinocyte?

A
  • Alpha Keratin: Pliable form of keratin- most abundant in keratinocytes of the epidermis.
  • Beta Keratin: Tougher form of keratin found in epidermal structures such as Claws, Scale and Hair.
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44
Q

What are the three phases of cytomorphosis of keratinocytes?

A

Proliferation: Production of new keratinocytes.
Differentiation: IKYK
Exfoliation: Keratinocytes at the surface are dead, shed and constantly being replaced by new cells.

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45
Q

What cells are the developmental sources of cutaneous appendages?

A

Basal Keratinocytes.

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46
Q

What is produced within keratinocytes of the stratum granulosum that is extruded from the cell and assists with cell binding in the stratum corneum.

A

Keratinosomes.
(Also may be called membrane coating granules.)

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47
Q

What are the three places melanocytes can be found?

A
  • Stratum Malpighi.
  • Hail Follicles
  • Dermal Connective Tissues.
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48
Q

What non-essential Amino Acid is used within a melanocyte to produce melanin?
What is this processes known as?

A

Tyrosine is oxidized into melanin.
Process is called Melanogenesis and occurs within the organelle: Melanosome.

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49
Q

What occurs within a melanocyte once melanogenesis is completed within a melanosome organelle?

A

The melanosome is transferred to adjacent keratinocytes via the cytoplasmic processes of the melanocyte.

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50
Q

What multilayer stratum houses the langerhans cells?

A

Stratum Malpighi.
Best found in the upper stratum spinosum.

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51
Q

What are langerhans cells derived from?
How does this relate to their appearance?

A

They are derived from Monocytes, this gives the langerhans cells their indented nucleus.

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52
Q

What are the rod shaped granules within Langerhans cells called?

A

Langerhans Granules.
(Function is undetermined.)

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53
Q

When langerhans cells are in the process of migrating to the lymph nodes to stimulate antibody production to an antigen?

A

They are called dendritic cells in this state.

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54
Q

Where 3 places Langerhans cells are found in the body?

A
  • Within stratified squamous epithelia: Esophagus, cervix, etc.
  • Cutaneous appendages: hair follicles, glands, etc
    Dermis
  • Lymph: Thymus, Lymph nodes & dermal lymph vessels.
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55
Q

Cells that are found mostly within the stratum basale and play a role in sensory function.
Where in the body are they common and what neural structure are they commonly associated with?

A

Merkel Cells.
- Usually found in areas where fine touch reception is important such as: Palms, Hair follicles/ Whiskers, Oral and Genital Mucosa etc.
- They are commonly associated with Merkel/ tactile discs: Sensory Nerve Fibers.

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56
Q

what are they two types of sudoriferous glands?

A
  • Apocrine: Thicker secretion, initially no scent, but once broken down (Usually by bacteria) associated with body odor. Pheromone secretions, begin to function at puberty, located in axillary and perianal areas.
  • Eccrine: Thermoregulation; Sweat, Widely distributed.
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56
Q

Sweat Glands AKA:

A

Sudoriferous Glands.

57
Q

What type of sudoriferous gland is the most widely distributed & associated with watery sweat production?
What three place is this gland not usually found?

A

Eccrine glands.
These glands are not usually found in Hirsute (Hairy) areas.
They are also absent in cetaceans (Marine Mammal) and sirens.

58
Q

What are the two classes of eccrine glands?

A

Shallow (Dermis).
Deep (Hypodermis).

59
Q

What is the excretion method of the two Eccrine Gland Cell Types?

A

Clear Cells: Watery Portion of sweat.
Dark Cells: Mucin (Glycoproteins.)
Both of them use Merocrine secretion, The light cells use active transport to facilitate merocrine secretion.

60
Q

Where are melanocytes derived from?

A

The Neural Crest.

61
Q

Type of sudoriferous Gland Which is found primarily in axillary and perianal regions and becomes active with the onset of puberty?

A

Apocrine Gland

62
Q

Where do apocrine glands secrete?

A

Into hair follicles, usually above where the sebaceous gland opens.

63
Q

What is one of the functions of apocrine glands that is associated with puberty?

A

The secretion of pheromones.

64
Q

What is the typical Gland structure of an apocrine gland?

A

Coiled Tubular Gland.
(Like an Eccrine Gland, but usually much larger Secretory Structures.)

65
Q

What is the epithelium of apocrine duct?
Secretory Portion?

A

Duct: Stratified Squamous (2 layers)
Secretory: Simple Cuboidal-Columnar.

66
Q

What are the secretion methods of apocrine Glands?

A

Merocrine
Apocrine
Holocrine

67
Q

Modified Apocrine Gland which lines the auditory canal?
Secretion?

A

Ceruminous gland
Secretes: Cerumen/ Earwax.

68
Q

Modified Apocrine Gland which produces nourishment for young in Mammals?

A

Mammary Gland

69
Q

Gland which is abundant all of the body aside from the pads and soles of feet/ hands?
Where is the secretion site?
Secretion Method?
Secretion Type?

A

Sebaceous
- Secrete into the upper hair follicle.
- Holocrine Secretion
- Secrete: Sebum (oil).

70
Q

Sebaceous gland structure?

A

Simple Branched Acinar.

71
Q

Sebaceous gland Epithelium?
Duct?
Secretory?

A

Duct: Staitifed Squamous Keratinzed.
Secretory: Acinar Cells in stages towards holocrine secretion.
- Outer cells have healthy nuclei
- Inner/ cells ready (accumulated lipids) to disintegrate and release contents will have pyknotic Nuclei and Die.

Pyknosis: Irreversible condensation of chromatin in the nucleus of a cell undergoing necrosis or apoptosis.

72
Q

What kind of epidermal appendage secretes sebum?

A

Sebaceous Gland.

73
Q

3 Properties of Sebum Oil?

A
  • Lubricates/ hydrates & softens hair and cornified skin.
  • Sometimes Pheromones
  • Release is under Hormonal Control.

Sebaceous Gland.

74
Q

Filamentous Strands of fused Keratinocytes?

A

Hair.

75
Q

Unit comprised of a hair follicle and sebaceous gland?

A

Pilosebaceous unit.

76
Q

What are the three steps of the hair growth cycle?

A
  1. Grow to a certain length
  2. resting phase
  3. Shed and replacment.
77
Q

What is Hair made of?

A

Keratinocytes filled with Beta-Keratin.

78
Q

What animal does not have a hair medulla?

A

Polarbears, this helps the solar energy be directed to the skin and the hollow cavity traps air for more insulation.

Thin fur/ hair is also unlikely to have a medulla.

79
Q

What is the expanded base at the root of hair called?

A

The Bulb.

80
Q

What are the two cells contained in the root papilla of a hair follicle?

A

Melanocytes: Provide coloration.
Matrix Cells: Pluripotent cells.

81
Q

Does the inner or outer rooth sheath come from matrix cells?

A

Internal/ Inner.

82
Q

Does the inner or outer rooth sheath come from the invagination of the basal epidermis?

A

External/ Outer.

83
Q

What are the three functions of hair/ fur?

A
  • Thermoregulation.
  • Protection.
  • Tactile Perception.
84
Q

What are the nerve endings at the end of a hair root called?

A

The Root Hair Plexus.

85
Q

What are repititious thickenings of the stratum corneum of the epidermis?
What class of vertebrate is the only one to have them?

A

Scales.
Amniotes: Development within amnion tissues: Mammals, Reptiles, Avians.

86
Q

What class of glands do avains lack?

A

Sudoriferous/ sweat glands.

Have limited sebaceous/ oil glands as well.

87
Q

What is a modification of avain skin which helps them regulate having such a high body temp?

A

They have a much thinner epidermis with less keratinization than others that allows for a “leaky” sort of evaporative cooling.

106-109

88
Q

Where are two places bird have sebaceous glands?

A

External Auditory Canal
Region of the cloaca.

89
Q

What is the large sebaceous gland at the base of the tail in aves?

A

The Uropygial Gland.

90
Q

What is the general anatomy of the uropygial gland?

A

it has two oil producing lobes which drain into the isthmus (Link/ Connection) which has an opening to the surface called the papilla (Small Projecting body.)
Birds will use this oil for preening.

91
Q

What type of keratin is found in feathers?

A

Beta-Keratin (Hard)

92
Q

Wwhat is the opening of the skin where the quill of a feather attaches?

A

Inferior Umbilicus.

93
Q

Feathers are arranged into a patter or tract across avian bodies, what are these tracts called?

A

Pterylae.

94
Q

Equivalent of arrector pilli in aves?

A

Arrector Plumarum

95
Q

Feathers grow to a certain length, rest, shed and then are replaced, what is this process?

A

The feather growth cycle.

96
Q

The skin of reptiles is highly cornified and is ________________ to water.

A

impermeable.

97
Q

What kind of keratin is within the keratinocytes of reptillian skin?

A

Beta-Keratin (Hard.)
This forms epidermal Scales.

98
Q

What is the most present type of integumentary gland in reptiles?

A

Granular Glands.
These Glands can/ may produce alkaloids which make the animal less appealing to predators.

99
Q

What is the method of secretion in reptillian Granulary Glands?

A

Holocrine.

100
Q

Some reptiles also have sebaceous glands in limited distribution. What is their secretion method and function?

A

Secretion: Holocrine
Function: Oils May assist in shedding.

These glands are histologically similar to mammals.

101
Q

Where do reptillian sebaceous glands open up?

A

Surface of the Skin.

Recall reptiles do not have hair.

102
Q

What is the stratum germinativum?

A

This is used in reference to the stratum basale in non-keratinzed skin or non-mammalian species’ skin.

103
Q

What stratums are commonly present in amphibian skin?

A

The stratum Germinativum/ Basale & Spinosum (5-7 cell layers.).
Mucus type epithelium usually does not have a granular or corneum layer.

Keratinocyte is still the main cell type.

104
Q

What is called when an animal with a stratified mucus type epithelium develops a minor amount of keratinization due to living some of it’s life not submerged in water (Think toads, or frogs that are in & out of water.)

A

Parakeratinization of mucus type stratified squamous epithelium.

Usually 1-2 layers of keratin rich “cornuem”. Alpha Keratin.

This keratinization + Folding gives the appearance of “warts” in toads.

105
Q

What is the main cell type of stratified squamous mucus type epithelium?

A

Still keratinocytes, but with a very reduced amount of keratinozation when compared to keratinized skin. This means the skin will be water permeable.

106
Q

Why do amphibians have many more integument skin glands than other vertebrates?

A

This is becuase the thin and moist epidermis of amphibians allows for respiration. Without glands producing mucus to keep the skin moist, they lose the layer of aqueous solvent for gases to diffuse into and travel beneath the epidermis. Dryness will damage their cell integrity and lead to shrikage, further reducing the ability for oxygen to diffuse beneath the epidermis to the cells that perform respiration.

Amphibian skin respiration is heavily relied on to provide 30-100% of oxygen depending on the species. (EX: Frog rely on this for 50% of their O2 needs.)

107
Q

What are the two most common types of glands in amphibians?

A

Multicellular mucus and granular glands.

108
Q

What is the structure of multicellular mucus glands in amphibians?

A

Simple Alveolar with secretory units located near the dermoepidermal junciton (DEJ).

DEJ is where epidermis and dermis meet.
Apodans (Limbless) have myoepithelial cells, while Anurans (Frogs) & Urodeles (Salamanders) typically lack them.
(These orders make up amphiba)

109
Q

What is the typical structure, location and secretion of granular glands in amphibians?

A
  • Large Alveolar
  • Deeper in the dermis.
  • Alkaloids: usually toxins

These glands usually have myoepithelial cells.

Think Bufo Frogs which produce a toxic (when ingested) mucus on thier skin.

110
Q

What is the epitheium type of the fish epidermis?
Most abundant cell type?

A

Stratified squamous epithelium with no parakeratinization.
Keratinocytes: Do not keratinize like mammals.

5-10 cells layers from stratum germinativum.

111
Q

What is the role of malpighian cells in the epidermis of fish?

A

They contain aggregates of intermediate fibers that may hold togther the cell layers.

112
Q

What is the interface between the dermis and epidermis called?

A

The Dermoepidermal Junction (DEJ)

113
Q

What is the most abundant cell type of the demis?

A

Fibroblast.

114
Q

The dermis is split into two layers.
What are they and what type of tissue is in each?

A

Papillary Layer/ Stratum Spongiosum
Reticular Layer/ Stratum Compactum.

115
Q

What type of tissue is the Stratum Spongiosum?

A

Spongiosum/ Papillary: Areolar c.t./ Loose c.t.

116
Q

What type of tissue is the Stratum Compactum?

A

Compactum/ Reticular: Dense Irregular c.t.

Reticular comes from the meshwork structure.
The dermis is not abundant in reticular fibers.

117
Q

Where are chromatophores usually located?

A

The dermis.
Exception: Melanocytes of mammals.

Chromatophores have dendritic endings to distribute pigment granules to nearby cells.

118
Q

Melanophore Color?

A

Shade of Brown/ Black.

119
Q

Xanthophore Color?

A

Yellow

Also a Lipophore: Soluble in lipids.

120
Q

Erythrophore Color?

A

Red

Also a Lipophore: Soluble in lipids.

121
Q

Iridophore Color?
What chemical Causes the color?

A

Reflective
Caused by guanine crysals.

122
Q

What class of vertebrates does the dermis not produce dermal bones?

A

Aves.

123
Q

What are the 4 layers of ancestral dermal bone from superficial to deep?

A
  • Enamel or enameloid (Modified dentin.)
  • Dentin
  • Spongy/ Cancellous Bone
  • Lamellar/ Cortical/ Compact Bone.
124
Q

What are the 3 main types of scales?

A
  • Rhomboid.
  • Elasmoid.
  • Placoid.
125
Q

What are the two types of Elasmoid scales?

Leptoid is the old name.

A

Ctenoid and Cycloid.

126
Q

What are the two types of Rhomboid scales?

A
  • Cosmoid (Anestral only- 4 layers.)
  • Ganoid- 3 layers (Enamel, Dentin, Cortical.)
127
Q

What are the layers of placoid scales?

A
  • Enameloid.
  • Dentin.
  • Cortical Bone.

Placoid scales have been used as covering for the handle of swords as it still provides grip when hands are sweaty. (Specifically shark skin.)

128
Q

What type of scale did teeth likely evolve from?

A

Placoid scales.

Placoid scales have been used as covering for the handle of swords as it still provides grip when hands are sweaty. (Specifically shark skin.)

129
Q

What class of fish have placoid scales?

A

Chondrichthyes

EX: Sharks & Rays!

130
Q

What are the dermal bones collectively referred to in tetrapods?

A

Osteoderm.
EX: Reptiles on dorsal surface & covered by epidermal scales- Alligator
Turtle shell = fused osteoderm.
Mammals: Only Armadillos & Spiny mouse (Tail.)

Apodans (Worm-like amphibians) & Toads still have more ancestral dermal plates.

131
Q

Dermis structure in agnathans?

A

Thinner than the epidermis. Almost entirely the reticular layer.

132
Q

Dermis structure in chondrichthyes & osteichthyes?

A

Thicker than epidermis, mostly reticular. Sheet of melanophores may be present at DEJ (Dorsal counter shading.)
Ost: Elasmoid or Ganoid Scales.
Chon: Placoid.

mc: Mucus Cell
psc: Placoid Scale.

133
Q

Where are fish and reptile scales usually located within the skin?

A

Fish: Dermis (at least arise from dermis.).
Reptiles: Epidermis.

134
Q

Dermis structure in amphibians?

A

Thicker than epidermis, mostly reticular, Beneath will be large lymphatic sinus with breeching collagen attachments. Dermal armor only in apodans and toads. Lots of vascularization for respiration.

Apodans: Worm-Like

135
Q

Dermis structure in Reptiles?

A

Thicker than epidermis, mostly reticular. Osteoderm.

136
Q

What two classes of vertebrates have the thinnest hypodermis?

A
  • Avians: Too much wieight, feathers are better at insulation & lighter.
  • Ectoderms: May even be absent.
137
Q

What are the two classes of hypodermis?

A

Panniculus Adiposus: Fatty -Well developed in humans
Panniculus Carnosus: Containts sheets of skeletal muscle (Usually Deep.) (Restricted to neck of humans.)

138
Q

What are the 3 neuro corpuscles of the skin?
Where specificaly are they found in the skin?

A

Meissner: Dermal Papilae (Finger tips.)
Pacinian: Dermis
Gential: External Genital regions only. (Similar to Pacinian.)

139
Q

Receptor within the epidermis which senses touch?

A

Meissner’s Corpuscle.

140
Q

Recepter within the dermis which sense vibrations?

A

Pacinian Corpuscle.

Comparative Vertebrate Histology (11 decks)

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