1.8 - Integument

Protection, sensory, thermoregulation

Name a few functions of integument (there are so many)

Epidermis, dermis, and hypodermis

3 integument layers

Ectoderm

What is the embryonic origin of epidermis

Mesoderm

What is the embryonic origin of dermis

mesoderm

What is the embryonic origin of hypodermis

rete apparatus

interdigitations of epidermal and dermal ridges that attaches the epidermis to the dermis

rete apparatus

What is this

Stratified squamous epithelium with or without kertaninization

What is the epithelium type of skin

Dermis

What determines if skin is thick or thin

Thin skin

thick or thin skin - right

Thick skin

Thick or thin skin - left

Hair and sebaceous glands

What does thick skin always lack

Palms and soles

Examples of where thick skin is found

Hair follicles, sebaceous glands, and sweat glands

What can be found within thin skin

Keratinocytes

The most abundant epidermal cells, they function mainly to produce keratin.

Stratum corneum

A

Stratum lucidum

B

Stratum granulosum

C

Stratum spinosum

D

Stratum basale

E

Stratum basale

which layer of the epidermis - basophilic cytoplasm, cells lie on BM, and the cells are actively dividing

Intermediate filaments of keratin

What does the stratum basale produce

The cell produces lots of keratin, which is a protein

Why would there be lots of free ribosomes in the stratum basale

hemidesmosomes

What connects the stratum basale to the basal lamina of the BM

Stratum basale

Which layer of the epidermis contains melanocytes

Melanocyte

what are the arrows pointing to within the epidermis

Stratum spinosum

which layer of the epidermis - multiple cuboidal cell layers, cell that is adjacent to stratum basale is mitotically active, tons of desmosomes

langerhans cells

specialized macrophages of the epidermis

Stratum spinosum

Within the epidermis, where are the langerhans cells found

Stratum granulosum

which layer of the epidermis - 3-5 layers of cells, last layer WITH nuclei, has many lysosomal enzymes, contains granules

keratohyalin and lamellar granules

2 types of granules found in the stratum granulosum

Keratohyaline

granules that bind and strengthen the tonofibrils and are produced by ribosomes

Lamellar granules

granule that produces a lipid rich secretion to waterproof the skin

Thick skin

Which type of skin would you find the stratum lucidum in

True

T/F - the stratum lucidim is likely just artifact

Stratum corneum

which layer of the epidermis - many layers of flattened and non-nucleated and keratinized cells with thick membranes and no organelles

desquamation

when epidermal cells lose desmosomes and the cell falls off

Golgi

What makes lamellar granules

melanocytes

Long irregular extensions between cells of the stratum basale and stratum spinosum that transfer pigment to nearby keratinocytes

False

T/F - all individuals have a different number of melanocytes

Different distribution of melanocytes

What causes the same animal to have different coloring in terms of how melanocytes work

melanoma

Caused by increased production of melanocytes from prolonged sun exposure

Dermis

connective tissue layer deep to the epidermis and separated from the stratum basale by a basement membrane

papillary and reticular layer

2 layers of the dermis

Papillary layer

Which layer of the dermis is this

Reticular layer

Which layer of the dermis is this

papillary layer

Layer of the dermis - loose CT that contains collagen and elastic fibers. Anchoring fibrils from the basal lamina of the BM connect it

reticular layer

Layer of the dermis - made of DICT, has collagen, elastic fibers, and smooth muscle. Will see some hair follicles too

Tension/langer lines

pattern of distribution of type I collagen fibers - determines tension and wrinkles in the skin and the pace of wound healing

Epidermis

Where does these integument derivatives always originate from - claws, nails, hair, sweat glands, and sebaceous glands

Hair

Elongated keratinized structures derived from invagination of epidermal epithelium

Hair

What is this structure in the integument

Sebaceous gland

sebum secreting gland that is surrounding each hair follicle and cradled by arrector pili muscles

Sebaceous gland

black arrow

Holocrine gland

gland type - accumulate products within, then ruptures

Holocrine gland

What type of gland is a sebaceous gland

Eccrine sweat gland

most numerous sweat-producing exocrine gland in the skin that functions in temperature regulation

Apocrine sweat gland

Sweat producing gland that can be for temperature regulation but also communication

tongue and foot pads

Where would we find eccrine sweat glands on mammals

merocrine secretion

Which type of secretion does eccrine sweat glands have

merocrine secretion

release of a substance from a gland via exocytosis

myoepithlial cells

What cells come into play whenever an eccrine sweat gland needs to quickly express sweat

Apocrine sweat glands

Identify the gland

Apocrine sweat gland

Other than the sebaceous gland, which gland can be associated with hair

Apocrine sweat gland

Gland that is always present anally and contains pheromones

puberty

When do apocrine sweat glands activate in a lifetime

Eccrine sweat glands

Identify the gland

Merocrine secretion

Which type of secretion do apocrine sweat glands use

Mammary glands

Which type of gland has apocrine secretion