Integumentary System Flashcards
The skin is made up by the ____ and the _____.
Dermis (connective tissue) and the epidermis (epithelium)
Exocrine glands, hair and nails are _____ structures.
Accessory
What is a major role of the integumentary system?
Physical and immunological protection, thermoregulation, sensation
What is the metabolic function of the integumentary system?
Synthesizing vitamin D and storing energy as subcutaneous fat
Which tissue type covers the surface of the body and forms a boundary?
The epithelial tissue
Which tissue type supports the epithelium and provides strength and resiliency?
The connective tissue
Which tissue type controls the diameter of the blood vessels and adjusts the hair position?
The smooth muscle tissue (autonomic nervous system)
Which tissue type controls smooth muscle and generates sensation and stimulates the exocrine glands?
The nerve tissue
What is the largest organ system in the body?
The skin
The skin represents about __% of total body mass and covers an area of about _ meters squared
15%, 2m squared
On average, the skin is _ - _ mm thick
1 - 2
Which layer is not really part of the skin, yet is still important when studying the skin?
The hypodermis/subcutaneous layer
What does the epidermal ridge interlock in a tight bond with? Why?
The dermal papilla. It helps to resist shearing stress.
How do the skin cells change shape as they reach the surface?
The dermis and papilla The stratum germinativum The stratum spinosum The stratum granulosum The stratum lucidum The stratum corneum
The thickest part of the skin is called the _____ _____.
stratum corneum
The translucent layer of the skin is called the _____ ____.
stratum lucidum
The darker colored layer of the skin is called the _____ _______.
stratum granulosum
As the skin layers rise to the surface, they become ____ ____. This process makes the cells ___.
Water proof. They die.
The most common type of cell in the epidermis is the _________
Keratinocyte
Keratinocytes form in the _____ ________ layer of the skin.
Stratum spinosum
The single basal layer deep in the skin is the ____ ______
Stratum germinativum/ stratum basale
The layer of skin that looks like hills and valleys is called the _____ _____.
Dermal papilla
The stratum germinativum is attached to the ____ ____.
basal lamina
The stratum spinosum is composed of __________.
Keratinocytes
Keratinocytes contain bundles of _________.
Tonofilaments
What do desmosomes do?
They attach keratinocytes together
In which layer do the cells become pigmented?
In the stratum granulosum
What does the stratum granulosum produce?
Keratohyalin, which turns into granules.
What does keratohyalin do?
It secretes lipids that fill the space between keratinocytes to form a water-repellent sealant.
What does the lipid sealant do to keratinocytes?
It prevents cell diffusion, leading to death
Why is the statum lucidum clear?
There is a large amount of keratin and thickened plasma membranes
Which layer is only found in volar skin? What is volar skin?
The stratum lucidum is in the skin of the palms and feet.
Which layer is made up of multiple layers of dead cells that are continuously shed and replaced?
The stratum corneum
What is the difference between thin and thick skin?
In thin skin, the stratum corneum is much thinner, the layers are not as clearly defined and the ridges and papillae are less developed (not as deep/tall).
Which layer of the dermis is thin and made of areolar connective tissue?
The papillary layer
Which layer of the dermis contains nerve endings?
The papillary layer
Which layer of the dermis is thick, dense, elastic and irregular?
The reticular layer
What are the aligned collagen fiber bundles in the dermis that are different in different regions of the body called?
Lines of cleavage
Why do lines of cleavage form the way they do?
Because collagen fiber bundles align along lines of tension
What is the problem with cutting against the line of tension during surgery?
A perpendicular cut will remain open and not heal very well.
What is another name for the hypodermis?
Superficial fascia
What is the hypodermis?
The loose connective tissue that stores fat and influences the shape/contours of the body
What is a merkel cell?
It’s linked with a neuron in the stratum germinativum and plays an imporant role in touch sensation.
What is the least common cell type?
The merkel cell
What is a langerhans cell?
It’s associated with the immune system, originating from bone marrow. They are able to consume foreign organelles in the skin, creating immunity.
What is a melanocyte?
They are responsible for pigmenting the skin by producing melanin
Melanocytes make up for about _% of epithelial cells
8%
Which cell type contains long slender processes full of melanin granules?
Melanocytes
What happens when blood supply travels through the dermis in pale skin in different ways?
The oxygenated hemoglobin changes the hue of the skin pink, or the deoxygenated hemoglobin changes the hue of the skin blue, the blood vessel dilation changes the hue of the skin red.
What color does carotene make the skin?
yellow/orange
What color does pheomelanin make the skin?
red/yellow
What color does melanin make the skin?
brown/black
How do melanosomes, lysosomes and keratinocytes work together?
Melanosomes are transferred to keratinocytes and color them. Keratinocytes move superficially, and the melanosomes are destroyed by lysosomes, which causes pigmentation loss.
What makes darker skin stay dark?
Melanosomes are larger and transfer to keratinocytes persists in the more superficial layers of the skin.
What increases the rate of melanin synthesis in response to UV radiation exposure? Why does melanin do this?
Melanocytes. Melanin synthesizes to prevent DNA damage from the radiation.
What does UV-induced skin damage do?
Causes chromosomal damage, skin cancer, damages fibroblasts, alters extracellular matrix and causes premature wrinkling
What do sebaceous glands do?
They secrete oily lipid (sebum) and coat the hair shafts & skin surface
What are the two major types of sweat glands? What’s the difference?
Merocrine (eccrine) glands secrete normal sweat (water & electrocytes, regulates body temperature)
Apocrine glands secrete odiferous sweat (smelly)
Which type of sweat gland is widespread?
Merocrine
Which type of sweat gland is found specifically in the axilla, groin, breast areola and male facial hair?
Apocrine
Why does apocrine sweat smell?
It secretes proteins, which are acted on by bacteria to produce odor. They’re stimulated during emotional stress and arousal
What are ceruminous glands?
Modified merocrine sweat glands that secrete waxy cerumen (ear wax).
What is the one “true” apocrine gland?
The mammary gland – specialized for milk production, regulated by interaction of sexual/pituitary hormones.
What does apocrine actually mean?
The gland takes parts of the cell membrane with the secretion.
What happens to sebaceous glands when they are inflamed?
Acne – inflammation results in duct blockage and bacterial infection
There are about ______ hairs on the body
5 million
Hair covers all body surfaces except ____ skin.
volar
What is at the base of a hair?
The hair bulb and hair papilla
What makes hair stand up when you’re cold or afraid?
The arrector pili muscle
What are vellus hairs?
Fine “peach fuzz” hairs found over most of the body
What are intermediate hairs?
Hair on the limbs, that change in response to sex hormones
What are terminal hairs?
Heavier and more pigented, found on the scalp, eyebrows and eyelashes
Hair grows about ____ mm per day.
0.33
How long does hair grow for? Then what happens?
Grows for 2-6 years, rests for about 3 months and becomes a club hair. Then a new hair grows in and pushes the old one out.
___% of hairs are in the growth phase at any given time.
85%
