Skin, hairs, nails lab and lecture Flashcards
Explain keratinization
As new keratinocytes move from the stratum basale to the skin surface, they accumulate more and more keratin, die, and form dead surface layers. This process takes 7-10 weeks.
sebaceous glands
What is the other name for the skin?
cutaneous membrane
thin skin
What are the two main parts of the skin?
epidermis and dermis
What is the name of the muscle attached to the hair, where is it located, and what is its function?
arrector pili muscle of hair (smooth muscle)
extends from papillary dermis to the dermal rooth sheath around the base of the hair follicle
create goose bumps during cold or fright
What are the functions of the stratum basale?
This is the only layer of the skin that undergoes mitosis and creates keratinocytes to replace the regularly shed ones from the top layer. The mitosis happens in the epidermal stem cells.
What are the three layers of the root and shaft of the hair starting from the inside?
medulla, cortex, and cuticle
What is the order of the layers of the epidermis starting from the most deep?
stratum basale, stratum spinosum, stratum granulosum, stratum lucidum (in thick skin), stratum corneum
stratum basale or germinativum
What is the average thickness of skin?
1-2mm
Pacinian corpuscle
What are two disorders that related to melanin production?
Albinism- complete lack of melanin production and genetic based
Vitaligo- parital or complete loss of melanocytes from patches of skin. Autoimmune based.
What is contained in eccrine and apocrine sweat?
Ions, urea ,uric acid, ammonia, amino acids, glucose, and lactic acid
dermal root sheath
Define sebaceous glands?
Oil glands that are simple, branched acinar glands.
nail bed or hyponychium
define the cortex
forms the major part of the shaft and consists of elongated cells
What are free nerve endings?
Dendrites that lack apparant structural specialization. Sense warmth, coolness, pain, tickling, and itching.
hair bulb
Structures?
dermal papillae
What are the two types of granules found in the stratum granulosum?
keratohyalin and lamellar granules
What do lamellar granules do?
release a water-repellent sealant that decreases water entry and loss and inhibits the entry of foreign materials
eccrine sudoriferous gland
epidermis
How many layers of cells are in the stratum spinosum?
8-10 layers of keratinocytes
matrix
Pacinian corpuscle
What is type of tissue is the stratum basale made of?
single row of cuboidal or columnar keratinocytes
What are the two additional cells present in the stratum spinosum?
Langerhans cells and the projections of melanocytes
hair shaft
What are the four principal cells in the epidermis?
keratinocytes, melanocytes, Langerhans/dendritic cells, and tactile epithelial cells.
Which layer of skin is vascular?
dermis
apocrine sudoriferous gland
what are the two types of epidermis?
thin(hairy skin) and thick(hairless skin)
What do sebaceous glands secrete and what is it’s function?
sebum which is a mixture of trigycerides, cholesterol, proteins, and inorganic salts. Coats the surface of hairs to keep them supple. Prevents excessive evaporation of water from skin, keeps skin soft, and inhibits the growth of some bacteria.
cortex
What is the inner/internal root sheath?
Produced by the matrix and forms a cellular tubular sheath of epithelium between the external root sheath and the hair. Provides a channel for the hair to grow in.
What is the integumentary system composed of?
skin, hair, oil and sweat glands, nails, and sensory receptors
What is in the subcutaneous tissue?
fat, large blood vessels that supply the skin, and pacinian corpuscles.
What is the other name for merkel cells?
tactile epithelial cells
cuticle
keratinocytes
How many layers does the stratum granulosum have?
3-5 layers of keratinocytes
texture of hair
straight
What is this in yellow?
medulla
Where is hair not located?
nipples, palms, palmar surfaces of digits, soles, plantar surfaces of feet, labia minora, and prepuce of the penis.
matrix cells
What are the three types of hair and what are their characteristics?
lanugo-fetal hair
terminal hair- coarse, heaily pigmented hair, often associated with secondary sexual characteristics at puberty
vellus hairs-peach fuzz
males have more terminal hair than females
What affects hair growth?
illness, radiation treatment, chemo, age, genetics, gender, and severe emotional stress. Extreme dieting, weightloss, and post partum.
nail body
hair follicle
Define apocrine sweat glands?
coiled tubular glands found mainly in the armpit, groin, areola, and beard areas. Release secretions via exocytosis NOT APOCRINE. Located in the reticular dermis and their ducts open into hair follicles.
Hair root
When do each type of sweat gland begin working?
Eccrine after birth
Apocrine during puberty
What is the other name of langerhans cells?
dendritic cells
What are the two types of melanin?
Eumelanin and pheomelanin
What is alopecia?
partial or complete lack of hair caused my genetic factors, aging, endocrine disorders, chemo, or skin diseases
Label starting with top left.
eponychium (cuticle), lunula, nail body, hyponychium, nail matrix
dermis
eccrine sudoiferous gland
dense irregular connective tissue
What two structures are associted with hair?
sebaceous glands and smooth muscle fibers
What causes fingerprints?
papillary ridges?? epidermal ridges?? sources differ
arrector pili
Label starting at top right
hypodermis and subcutaneous tissue
Keratinized stratified squamous epithelium
Why is the stratum spinosum called that?
Spinelike projections made of keratin filaments insert into desmosomes
What are meissner corpuscles?
Nerve endings sensitive to fine touch and vibrations.
What things are in the reticular dermis?
Netlike structure of collagen fibers which resist skin stretching, blood vessels, nerves, hair follicles, sebaceous glands and sudoriferous glands.
What are the three stages of hair growth? What are they characterized by?
Growth- cells of the hair matrix divide and cause hair to grow longer 2-6 years
regression stage- hair matrix stops dividing 2-3 weeks
resting phase- hair root falls out 3 months
What are the functions of hair?
Protection and light touch sensation
What do the keratinocytes produces?
lamellar granules
stratum corneum
Define ceruminous glands?
modified sweat glands in the external ear that produce wax (cerumen). Are located in the subcutaneous layer. Provide a barrier against foreign bodies and insects. Waterproofs meatus and protects from bacteria and fungi.
define the hair cuticle
single layer of flat thin cells that are the most heavily kerotinized. Aranged like shingles on a house.
stratum corneum
texture of hair
wavy
What do merkel cells make contact with in the dermis that is important to their function?
They make contact with a neuron type cell called non encapsulated sensory corpuscle.
What is the description of the papillary dermis?
Superficial portion of the dermis (1/5) consisting of areolar connective tissue with thin collagen and fine elastic fibers, contains dermal ridges that house blood capillaries, tactile corpuscles, and free nerve endings.
What is the distinctive feature of cells in the stratum granulosum?
the dark staining granules of protein called keratohylin
Define the medulla
two to three rows of irregulary shaped cells that contain pigment granules
hari follicle
Label starting at the top right
What influences thickness and pattern of hair distributions?
genetics and hormones
what is the hair root plexus?
dendrites of neurons surrounding the hair follicle that are sensitive to touch
What type of cell junction is present in the stratum basale?
desmosomes and hemidesmosomes
What increases melanin production?
Esposure to UV
What is the main function of eccrine sweat glands?
thermoregulation via evaporative cooling
also release sweat during emotional stress
Where do langerhans cells come from?
red bone marrow
What is the main function of melanocytes?
Produce melanin which gives skin pigment
What organ is carotene important for?
the eyes
What is the difference between the sweat released by eccrine glands and the one released by apocrine glands?
Apocrine contains lipids and protein and has a musky odor because of bacterial interaction.
Region?
papillary region
What is the external root sheath?
The outer root sheath (ORS) is an extension of the epidermal basal layer which envelopes the entire hair follicle (HF). In addition, the ORS contains a number of functional compartments: the bulge, which serves as a reservoir for hair stem cells, and the sebaceous gland, responsible for hair lubrication.
What are the accessory structures of the integumentary system?
hair, glands, and nails
What action stimulates increased cell production and keratin that forms a callus?
friction
Where are Merkel/tactile epithelial cells located?
deepest layer of the epidermis
How many layers does thin skin have?
4
What are the 6 functions of the integumentary system?
- regulates body temp
- stores blood
- protects body from external environment
- detects cutaneous sensations
- excretes and absorbs substances
- synthesizes vitamin D
How do nutrients and oxygen get to the nonvascular epidermis?
They diffuse from the blood vessels in the dermis. The stratum basale is closest to the dermis and receives most of this, allowing them to be more active and produce new cells.
What are the functions of merkel/tactile epithelial cells?
detect light touch sensations
What are the two layers of the dermis?
papillary dermis and reticular dermis
papilla of the hair
Besides keratinocytes, what two other cells are present in the stratum basale?
melanocytes and merkel/tactile epithelial cells with their sensory corpuscles.
external epithelial root sheath
Define eccrine glands
simple, coiled tubular glands located in the reticular dermis and end in a pore on the surface of the epidermis and produce sweat. They are merocrine-type secretion glands.
Where is the hair root located?
the dermis and sometimes the subcutanous tissue
internal epithelial root sheath
What are the three main substances that affect skin color?
Melanin, hemoglobin, and carotene.
What causes darker or lighter skin?
The amount of pigment the melanocytes produce. Everyone has roughly the same amount of melanocytes
Where are eccrine sweat glands
throughout the body and especially on the forehead, palms, and soles.
Where is the hair shaft located?
above the skin
areolar connective tissue
What process are keratinocytes undergoing in the stratum granulosum
apoptosis (cell death)
stratum spinosum
What are the functions of langerhans cells and what type of cell are they?
cell type: macrophage
participate in immune responses against microbes, they help other cells of the immune system recognize invading microbes
Easily damaged by UV light
What are dermal papillae and how are they identified?
small nipple shaped structures that project into the bottom of the dermis. Contain capillary loops, meissner corpuscles, and free nerve endings. Create finger prints.
How many layers are in the stratum corneum?
25-30 layers of flattened dead keratinocytes
What type of tissue is the epidermis made of?
What type of tissue is the dermis made of?
epithelial
connective tissue
Where are sebaceous glands located in the tissue and on the body?
Usually connected to hair follicles in the dermis and the opens up into the neck of the hair follicle
Located in lips, glans penis, labia minora. Small in trunk and limbs, large in breasts, face, neck, and superorior chest. Absent in palms and soles.
What is the dermis comprised of?
dense irregular connective and areolar tissue
How many layers of stratum lucidum are there?
4-6 layers of flattened clear, dead keratinocytes
stratum lucidum
What is below the dermis?
subcutaneous tissue
lunula
In what form does melanin come in?
granules
stratum granulosum
reticular region
What type of tissue makes up the epidermis?
keratinized stratified squamous epithelium
What is the subcutaneous tissue also know as?
hypodermis
What are the three main types of glands in the skin and what are the ones that fall under them if applicable?
Sebaceous Sudoriferous -eccrine -apocrine Ceruminous
What is the definition of the reticular dermis?
Deeper portion of the dermis (4/5), consists of dense irregular tissue with bundles of thick collagen and some coarse eleactice fibers. Spaces between fibers contain some adipose cells, hair follicles, nerves, sebaceous glands, and sudorferous glands.
What is the other name for stratum basale?
stratum germinativum
What is this?
hair cuticle
layer
external epithelial root sheath
Where is the hair follicle and what are the two layers of it?
Surrounding the hair root
external root sheath and internal rooth sheath
thick skin
Which cell is most abundant in the epidermis?
keratinocytes
How does melanin protect cells from UV light?
Melanin granules cluster to form a protective veil over the nucleus of keratinocytes to shield nuclear DNA from UV light.
Melanocytes are very susceptible to UV damage.
What are capillary loops?
blood vessels
Specific layer
internal epithelial root sheath
What are sudoriferous glands?
sweat glands
How many layers does thick skin have?
5
texture of hair
curly
What is carotene a precursor to?
Vitamin A
eponychium or cuticle
Which skin contains epidermal ridges?
thick skin
What are nails made of?
keratinized epidermal cells
In which type of skin are sweat glands more numerous?
thick skin
In which type of skin are sebaceous glands absent?
thick skin
Which type of skin has more sensory receptors?
thick skin
How does the skin help with thermoregulation?
Sweat and blood flow to the dermis. dialation and constriction of blood vessels
What percentage of the blood is held in the dermis?
8-10%
How does the skin protect the body?
keratin, lipids released by lamella granules, sebum, acidic sweat, macrophages (langerhans cells)
What is the precursor molecule in vitamin D production?
calcitrol
Overview of epidermal wound healing
No blood lost/superficial
Stratum basale is activated by epithelial growth hormone to create more cells from the epidermal stem cells, these cells move up to replace the lost or damaged cells. Takes about 7 days to heal
Overview of deep wound healing
Blood involved, injury down to dermis
- vasoconstriction to stop blood loss
- platelets create clot
- WBC go to injury, neutrophils then macrophages
- cell mitosis to create new cells to replace damaged/lost ones
- cell maturation
Six age associated changes
- wrinkles
- dehydration and cracking of skin
- sweat production decreases
- numbers of functional melanocytes go down
- subcutaneous fat is lost and skin thickness decreases
- nails become more brittle
Cause of skin cancer and the three major types
Excessive exposure to UV
basal cell carcinoma, squamous cell carcinoma, and malignant melanoma
What causes burns?
Excessive heat, electricity, radioactivity, or corrosive chemicals that denature the proteins in the skin
How are burns graded?
By their severity First degree(sunburn)- just epidermis Second degree- down to dermis, blisters on the skin Third-degree- down to hypodermis
What is the rule of nines?
A method for splitting up the body into percentages to calculate the % of the body that is burned.
Exam: Perineum is 1%
Define pressure ulcers (bed sores) and what type of patient has them often?
When shedding of epithelium caused by a deficiency of blood flow to tissues occurs, pressure ulcers can develop
Older patients and diabetic patients
What system does vitamin D work with besides the integumentary and skeletal system?
immune system
