Exam 2 Skin and related organs

cluster of mesodermal cells that form radiating out from notochord

the somites

what are somites

• dermatome

• myotome

• sclerotome

  They are segmented structures that give rise to various tissues in the developing embryo, including the dermis, skeletal muscle, and vertebrae.

dermatome

will become the dermis

as the dermis grows out it

stretches the ectoderm out with it

dermis is

mesodermal

epidermis is

ectodermal

what is below the epidermis

the basement membrane that attaches the epidermis to the dermis

as the dermatome radiates out it

takes the dermis and extensions of the nervous system to the skin surface.

The myotome matures into

muscle

What forms from the sclérotome

bones that develop from the somite in the embryo.

dermatome map

mapping of each set of nerves coming from the dorsal hollow nerve chord and all parts of the body where the nerve is innervating

where do our arms come from

the C6, C7, C8 dermatomes extending from the spinal cord to the upper limbs.

Integument

skin

Functions of the integument

1. Protection

2. communication

3. respiration

4. produce auxilary structures

Integument protection

a) physical protection

b) osmoregulation

c) thermoregulation

d) immune function

e) radiation

F) crypsis

osmoregulation

the process of regulating water and electrolyte balance in the body.

thermoregulation

the process of maintaining a stable internal body temperature despite external temperature changes.

immune function

the role of the immune system in protecting the body from pathogens and diseases.

radiation

the emission and transfer of heat through electromagnetic waves, which can impact temperature regulation in the body.

crypsis

the ability of an organism to avoid detection by predators through camouflage, mimicry, or concealment.

Integument Communication

the role of the skin and related organs in sending and receiving signals, such as sensations and hormonal responses.

Integument Respiration

the process by which the skin and associated organs facilitate gas exchange, allowing for limited respiration in some organisms. (breathing through the skin) only aspect humans have is cornea cells respiring through the cells (more common in aquatic organisms like amphibians and certain fish)

Integument produce auxiliary structures

such as hair, nails, and glands that support various functions including protection, temperature regulation, and sensation. (the production of anything growing out of the skin)

The hair dives into the epidermis and has

glands that dive all the way down to the bottom of the dermis

the hypodermis

is the lowest layer of the skin, composed mainly of fat and connective tissue, providing insulation and cushioning for the body.

arteries and veins run though

the deepest layer of the dermis

Pain sensors are on

the boarder of the epidermis and dermis (so they are shallow) this is how paper cuts hurt but do not bleed

Arrector Pili Muscle

associated with every hair follicle, it contracts to cause hair to stand up. (this is what the goose bumps/chills are)

Hair follicles and other structures are ________ _______ in the dermis

epidermal inclusions

the epidermis has how many layers

5

Stratum corneum

outer most layer of the epidermis that is a layer of dead cells (it is what’s keeping liquids and salts in our body)

Stratum granulosum

cells that are in the process of dying and the water is drying out of them

Stratum basale

Deepest layer where the cells are going through mitosis

there are several kinds of glands that are also

epidermal derivatives

Sebaceous gland

a gland that produces an oily substance called sebum, which acts as a natural conditioner to the skin and hair and keeps hair in it’s place

Apocrine sweat gland

Deeper embedded than the sebaceous gland and they secrete proteins and lipids that fertilizes microbes growing in the hair this is what causes body odor (the odor is not the secretion, it is when the microbes consume the secretions and produce waste products that emit scent.)

eccrine sweat gland

(not associated with hair or odor) secretes salt water that evaporates off the body when it evaporates it helps regulate body temperature through cooling.

all glands in the body are produced by

epithelia cells

Exocrine glands

secrete to outside of the body

Endocrine glands

deliver by the blood stream (hormones are this system)

dermal papilla

little bump that grows in response to the ectoderm doing something, eventually it will cause a developmental change in the ectoderm then the dermis causing auxiliary structures

stratum corneum

consists of dead highly compact keratin (skin cells) at the base of the nail it is pushing out the thick contained stratum corneum

hoof

epidermis jammed pack with a thick keratin with more dermis that is retained

finger nail

epidermis jammd pack with thick keratin but dermis is not retained

amphibian skin have

synapomorphic derived trait that has lots of exocrine glands

granular glands

grains throughout skin that have poison compounds

mucous glands

clear solution that keeps skin moist

why do amphibians have mucus glands

for their respiration because amphibians breath through their skin

melanophores

color baring cells that contain black pigmentation that vertebrates possess These cells help in camouflage and thermoregulation, allowing animals to adapt their color to their environment.

what are snakes and lizards scales made of

folded epidermis and keratin without dermal papilla

dentine has

a base of dermal papilla (soft bone)

Enamel produces

dentine

Dentine comes from the

mesoderm (dermis)

Enamel comes from

Ectoderm (epidermis)

Two types of structures produced by enamel and dentine interacting

• tooth

• placoid scale

placoid scales (denticles)

scale type present in sharks with an inner pulp cavity

What are derived from placoid scales

teeth

Cosmoid

fused placoid that is present in lungfish, and are plated in cosmine (dentine like)

Ganoid

in primitive bony fishes (gars), derived from cosmoid scales and have a ganoine outer layer that are socketed together

All scale types have a

dentine base

leptoid

scale type in most modern day ray finned fishes they are smaller and softer delicate scales, that are round and overlapped with a collagen base

osteoderms

dermal bone added protection under scales

carapace

hard protective outer shell found in turtles and some crustaceans, formed from fused bones that cover the back and sides.

what does the dermatocranium produce in ungulates (hoofed animals)

bony outgrowths

horns are

both dermal and epidermal and are permanent

Antlers are

only dermal covered in velvet which falls off leaving only the dermal bone and this happens seasonally each year.

What happens in antlers

When testosterone is at a high it cuts off blood flow causing the velvet to shed, exposing the hardened bony structure underneath.