Topic 9 -Integumentary System Flashcards
Integumentary system consists of
Skin
Hair, nails, glands,
Sensory receptors
Muscle
What are the two Skin layers, what is below them
Epidermis (upper)
Dermis (lower)
Hypodermis is below skin
Epidermis
cell type?
vascular or avascular?
how many layers?
Stratified squamous epithelium (from ectoderm)
Avascular
Separated into 4 to 5 strata (layers) based on cell types
Layers of epidermis (5)
Stratum basale (lowest layer)
Stratum spinosum
Stratum granulosum
Stratum lucidum (only in thick skin)
Stratum Corneum (top layer)
Stratum basale -lowest layer
how many rows of cells?
2 cell types, what are they?
Single row of cells
Keratinocytes
Melanocytes
Keratinocytes (90%)
what do they do?
what do they make?
Undergo mitosis
Make keratin (tough protein)
Migrate to surface as new cells produced in basale
Melanocytes (10%)
Produce pigment, melanin, for UV light production
Sunburns, wrinkles (collagen damage), cancer DNA damage
Stratum spinosum
cell division is?
Limited cell division
Stratum granulosum
what does it contain?
Contains dark staining granules
Stratum lucidum
what do the cells look like?
visible only in?
Flat dead cells (too far from blood supply)
Visible only in thick skin
Stratum corneum
how many layers of cells?
what is inside the cells?
what surrounds the cells?
20-30 layers of flat, dead cells filled with keratin surrounded by waterproofing glycolipids to prevent water loss
Shed and replaced from below
Dermis what does it contain? Two sublayers (CT from mesoderm)
Contains blood vessels, nerves, glands and hair follicles
Papillary layer
Reticular layer
Papillary layer
what type of CT?
vascular or avascular?
what does it have, what do these form in thick skin?
Areolar CT
Vascular
Has projections into the epidermis -dermal papillae
In thick skin these form dermal ridges (finger prints)
Reticular layer
what CT type
Most of dermis
Dense irregular CT
Hypodermis
Subcutaneous layer
Superficial fascia (CT layers that surround and support organs)
Adipose CT below skin
Store 1/2 of body’s adipose tissue (insulation)
Thin skin
what does it have?
Lucidum not apparent
Has hair follicles, subaceous glands, arrector pili muscles
Thick skin
where is it found?
Found on palm of hand and sole of foot
Lucidum visible
No hair follicles, sebaceous glands or arrector pili muscles
Hair
what are the parts
all dead cells parts: hair follicle -surrounds root root -dead cells below skin surface shaft -above skin surface
each hair follicle has
epithelial root sheath -several epidermal layers extend into dermis
bulb -expanded region at base of root
hair matrix -single layer of cells derived from basale cells, site of hair growth and melanin for hair colour
dermal root sheath
holds follicle in place (formed from dermis)
hair papilla
where does it extend?
what does it contain?
what does it signal for?
extends upwards beneath matrix
contains blood supply for growing hair and signals for regulation
dermal
root hair plexus
free nerve endings for touch
sebaceous glands
opens into follicle
arrector pili muscle (smooth muscle)
causes goosebumps
nails
very heavily keratinized epidermal cell
consist of nail root
body
free edge
skin exocrine glands 4 types
sebaceous glands
sudoriferous glands
ceruminous
mammary glands
sebaceous glands
connected to hair follicles
secrete sebum (Oil)
soften and lubricates skin and hair, prevents drying out, antibiotic
sudoriferous glands
sweat glands
secretory portions in dermis
ducts open onto surface
sweat cools the body, is antibiotic and removes waste
ceruminous
modified sweat glands in ear canal
produce ear wax
mammary glands
modified sweat glands
produce milk
4 major types of cutaneous receptors
touch
pressure
thermoreceptors
nociceptors
touch receptor
where are the free nerve endings?
what does the root plexus detect?
what is the name of the nerve in the dermal papillae?
free nerve ending in epidermis
root hair plexuses detect hair movement
meissner corpuscle in dermal papillae
corpuscle -CT capsule surrounds nerve endings
pressure receptor
where are the free nerve endings?
what is the name of the nerve?
free nerve endings in dermis
pacinian corpuscle -deep in dermis or hypodermis
thermoreceptors
free nerve endings for temperature
nociceptors
free nerve endings for pain
3rd degree burns feel no pain because nociceptors are destroyed
