Chapter 5
How are lactose acid and urea eliminated?
Via sweat
What is calcitriol?
active form of vitamin D
What is the hair matrix?
actively dividing area of the hair bulb that produces the hair
Glands that release sweat into hair follicles are called __________.
apocrine sweat glands
Apocrine glands are found where?
axillae, genitalia, areolae
What are the five strata of the epidermis from superficial to deep?
corneum, lucidum, granulosum, spinosum, basale
The bluish coloration of skin due to the reduced levels of oxygen is called
cyanosis
What is the reticular layer made of?
dense irregular connective tissue
What tissue composes the reticular layer of the dermis?
dense irregular connective tissue
What is the hair papilla?
dermal tissue containing a knot of capillaries that supplies nutrients to growing hair
How are keratinocytes connected?
desmosomes
What is the most prevalent type of sweat gland?
eccrine sweat glands
The most superficial layer of the cutaneous membrane is called the
epidermis
What are the components of skin?
epidermis, dermis, accessory structures
Where can you find Sebaceous glands?
everywhere except palms and soles
describe lanugo hair
fine, downy, unpigmented hair that appears on the fetus in the last 3 months of development
The unique, characteristic pattern of the epidermal ridges is visible as
fingerprints
What type of burn is sunburn?
first degree
A burn that only damages the epidermis is classified as a __________.
first degree burn
Where do apocrine sweat glands empty?
hair follicle
Hair growth occurs at the
hair root
What are the accessory structures in skin?
hair, nails, glands
What does keratin do?
helps protect skin and underlying tissues from heat, microbes, and chemicals=strength
How do sebaceous glands secrete?
holocrine secretion (cells burst)
The most numerous cells of the epidermis are the
keratinocytes
What are the most abundant cells found in the epidermis?
keratinocytes
What are the 3 different types of hair?
lanugo, vellus, terminal
What is the function of merkel cells?
light touch sensation
What is the papillary layer made up of?
loose connective tissue
What is the pigment that protects the DNA of keratinocytes from mutations induced by UV radiation?
melanin
What determines hair color?
melanin production
What do mammary glands secrete?
milk
Actively dividing cells in a nail are found in the
nail matrix
Nail growth occurs where?
nail matrix
Where are the actively dividing cells found in the nail?
nail matrix
Sebum is an
oily mixture that lubricates skin and hair
If an infant consumes too much carotene from baby food, her skin might turn __________.
orange
What does pallor mean?
pale appearance
Where can you find thick skin?
palms of hands and soles of feet
Predict which of the following regions of the body will have predominantly thick skin.
palms, soles of the feet
What is the structure of the dermis?
papillary layer and reticular layer
What is the function of dendritic cells?
phagocytic activators of the immune system
What is the function of keratinocytes?
produce keratin
What is the primary function of melanin?
protecting keratinocyte DNA from damage by UV radiation
What are the functions of the dermis?
provides blood supply for epidermis, contains sensory receptors, anchors epidermis in place
What does erythema mean?
redness
What is the secondary function of melanin?
reduce synthesis of vitamin D in response to UV radiation
What is secreted from sebaceous glands?
sebum
What is the arrector pili muscle made of?
smooth muscle
Dividing stem cells that give rise to keratinocytes are located in the
stratum basale
Where can you find melanocytes?
stratum basale
Where can you find merkel cells?
stratum basale
Where can you find dendritic cells?
stratum spinosum
Hypodermis is also known as
superficial fascia or subcutaneous layer
What is the name of the thicker, coarser, more pigmented hair found on the scalp?
terminal hair
How long do eyelashes stay in the growth stage?
About 30 days
Where is the lanula located?
On top of the distal nail matrix which is thick and cells have accumulated keratin
What is the eponychium consist of?
Only the stratum corneum
hair follicle
Sheath enclosing the hair root;it consists of two layers of tissue: the epithelial root sheath and the outer dermal root sheath
Describe the hair cuticle layer.
Single layer of over lapping keratinocytes
How is cholecalciferol made?
UV exposure causes the precursor of vitamin D to be converted into cholecalciferol
What is a freckle?
Small area of increased pigmentation due to a local increase in melanin production
describe the hair medulla
Soft core or soft keratin
What type of skin cancer forms plaques that bleed or ulcerate?
Squamous cell carcinoma
Where will carotene accumulate?
Stratum corneum
What is the function of collagen bundles?
Strength
True or false Cells in the hair root are alive and still undergoing keratinization
True
True or false The number of melanocytes is nearly identical across individuals?
True
Describe stratum lucidum
- narrow, clear layer of dead keratinocytes - found only in thick skin Found only in thick skin
What is the average hair growth?
1-1.5 cm per month
What molecules make up melanin?
2 molecules of tyrosine joined by the enzyme tyrosinase
Describe thin skin
4 layers NO stratum lucidum Numerous hairs, sweat glands and sebaceous glands
How long does it take for cells to go from the stratum basale to the stratum corneum?
40-50 days
Describe thick skin
5 layers No hair follicles Many sweat glands
arrector pili muscle
A bundle of smooth muscle fibers connected to a hair follicle;when stimulated, the muscle causes the hair to stand up, this causing "goosebumps"
What causes melanin production to decline?
Aging
What is a mole?
An area of increased pigmentation due to local proliferation of melanocytes
What is the hair follicle created by?
An in folding of the epidermis
What is cholecalciferol?
An inactive form of vitamin D
Hemoglobin
An iron-containing protein in red blood cells that binds oxygen.
What is the purpose of the papillary layer?
Anchor the epidermis to the dermis
rules of nines: list the body parts and percentages
Anterior/front: head-4.5, arms-4.5, trunk-18, legs-9, genitalia-1 Posterior/back:head-4.5, arms-4.5 per arm,trunk-18, legs-9 per leg
Skin gland primarily located in the axillary, anal and genital areas; becomes active at puberty
Apocrine gland
How long does it take to see the delayed response to UV radiation?
Appears within 72 hours and lasts longer than melanin oxidation
How long does scalp hair stay in the growth stage?
Approximately 6 years
Keratinocytes in the stratum corneum __________.
Are dead and filled with keratin
How is malignant melanoma characterized by?
Asymmetrical shape, irregular boarders, color, large diameter and evolving nature
Describe where the hair bulb is
At the bottom of the hair root
What type of skin cancer generally forms a nodule with a cratered center?
Basel cell carcinoma
What does cyanosis mean?
Blue hue
Describe the stratum basale
Bottom layer resting on basement membrane -single layer of stem cells -MOST metabolically and mitotically active cells -produces the precursor to vitamin D and replaces dead keratinocytes
How does hemoglobin indirectly affect skin color?
By the result of blood flow, giving a faint pinkish hue
basal cell carcinoma
Cancer of keratinocytes in the stratum basale
squamous cell carcinoma
Cancer of the keratinocytes in the stratum spinosum
The papillary layer houses what?
Capillary loops and tactile corpuscles
Modified sweat glands found in the ear canal;produce ear wax to lubricate the tympanic membrane
Ceruminous gland
What can cause pallor?
Cold environment, fight or flight response, reaction to fear or severe infection
What is found in the reticular layer?
Collagen bundles, elastic fibers, proteoglycans, lamellated corpuscles, blood vessels, sweat glands, hair, Sebaceous glands and adipose tissue
Skin is also know as what?
Cutaneous membrane
What is bodies delayed response to UV radiation?
DNA damage in melanocytes causing the stimulation of melanin production
Are the cells in the hair shaft dead or alive?
Dead
Where is the hypodermis located?
Deep to the dermis
Describe the dermis
Deep to the epidermis, made of loose connective tissue and dense irregular connective tissue
What are the different cells in the epidermis?
Dendritic cells, Merkel cells, melanocytes
What does hair detect?
Detects changes in the environment via a small sensory neuron
What can cause cyanosis?
Difficulty breathing, low hemoglobin or when hemoglobin is unable to bind to oxygen
What is the function of capillary loops?
Diffusion of oxygen and nutrients
What is the function of proteoglycans?
Draws water to keep skin hydrated and firm
Why do we have different skin tones?
Due to the amount of tyrosinase activity and the type of melanin being produced
What so ceruminous glands secrete?
Ear wax
Sweat gland found covering most of the body;primarily function is temperature regulation
Eccrine gland
What are stretch marks?
Elastic fiber tears in the dermis: reticular layer
What is the name for the in folding of the epidermis
Epithelial root sheath
23%
Estimate the percentage of body surface affected if the anterior portion of the body inside the red square has been damaged
What can cause erythema?
Exercise, trauma, fever or infection
What type of cells are found in the papillary layer?
Fibroblasts and phagocytes
What causes indentations in the epidermis?
Gaps between collagen bundles in the dermis
What are the 2 cycles of hair growth?
Growth stage, resting stage
The hair root is embedded where?
Hair follicle
Sebum secretions are influenced by what?
Hormones
second degree burn
If the gray area is burned then this figure illustrates a
Dermal ridges are found where?
In areas where the dermal papillae are more prominent due to thick collagen bundles
What is the function of epidermal ridges?
Increase the gripping ability of the hands and feet
accessory structures are also referred to as what?
Integument
Skin markings arise from what?
Interactions between dermis and epidermis
What is the function of the hypodermis?
It anchors the skin to the underlying structures It allows the skin to slide freely
Both the shaft and the root are made up of what kind of cells?
Keratinized epithelial cells
What is the function is tactile corpuscles?
Light touch sensation
What is the hypodermis consist of?
Loose CT and adipose tissue
What does the integument protect from?
Mechanical trauma, pathogens and external environment
How do Apocrine sweat glands secrete?
Merocrine secretion
Describe the stratum granulosum
Middle 3-5 layers, cells have granules such as keratin bundles or lipid based substance that can be secreted by exocytosis
What happens in the resting stage?
Mitosis in the matrix ends, the cells die. The follicle shortens and the hair is pushed toward the surface to remain dormant before falling out or being pushed out by a new hair
What happens during the growth stage?
Mitosis occurs in the matrix
Experiment sweat glands secrete what?
Mostly water, waste products and electrolytes
What is calcium needed for?
Nerve function, muscle contractions, building and maintaining bone
Cuticle
Outermost layer of the hair shaft
What is the bodies immediate response to UV radiation?
Oxidation of melanin already present in keratinocytes which causes the melanin to quickly darken
What is the superficial layer of the dermis composed primarily of loose connective tissue called?
Papillary layer
What is the function of lamellated corpuscles?
Pressure and vibration sensation
What does hair prevent?
Prevents substance from the external environment entering the eyes and nose
What is the function of hair?
Prevents, protects, and detects
What is the function for melanocytes?
Produce melanin
What are the functions of the nail?
Protection to underlying tissue, act as a tool to enhance gripping
What are the functions of the integument?
Protection, sensation and thermoregulation
What does hair protect?
Protects underlying skin of the scalp from UV radiation and mechanical trauma
What does the arrector pili muscle do?
Pull the hair so it stands up called piloerection
How many pounds of skin cells do you loose per year?
Roughly 8 pounds
An oily substance that Coates and conditions the skin and hair is secreted by the
Sebaceous glands
What type of burn only involves injury to the epidermis and part or all of the dermis? Normally has blistering
Second degree
Describe the hair cortex
Several layers of keratinocytes
What influences apocrine glands?
Sex hormone
tension lines
The blue lines on this figure are called
A
The dermal papillae are labeled
Where does the arrector pili muscle attach?
The dermal root sheath and the dermal papillary layer
How is calcitriol made?
The inactive form,cholecalciferol, enters the blood stream and is modified by the liver and the kidneys to become calcitriol
Melanocyte
The large cell in the middle is a
Describe the stratum corneum
The outermost layer of skin, closely packed cells with keratin, act as a waterproof barrier.
What is the lunula?
The pale crescent at the base of the nail
What layer is responsible for tension lines and flexible lines?
The reticular layer
C
The reticular layer of the dermis is labeled
Why do apocrine secretions smell?
The skin bacteria metabolize the secretion
Describe the epidermis
The superficial layer made of keratinized stratified squamous epithelium
Describe the stratum spinosum
The thickest layer -sits on top of the stratum basale so it is close to the blood supply -cells here are metabolically and mitotically active -cells appear spiky due to the cytoskeleton filaments in the cells periphery -assists with vitamin D production
The medulla can only be found in what type of hair?
Thick hair
Describe terminal hair
Thick, coarse, pigmented hairs that surround the eyes and on the scalp
describe vellus hair
Thinner, non pigmented hairs that cover the rest of the body
Sweat also contains antimicrobial compounds and has a slightly acidic pH, which inhibits growth of pathogens. True or false?
True
True or False The integumentary system plays a small role in excreting waste products.
True
What does the release of the granules provide?
Waterproofing to maintain internal fluid and electolytes
Sweat glands release sweat and blood vessels dilate
Which of the following describes the effector response of sweat glands and blood vessels?
Describe carotene
Yellow to orange pigmentation
What is the most common type of skin cancer, which results in the formation of a nodule with a central crater that ulcerates?
basal cell carcinoma
In order from deep to superficial, what are the five strata of the epidermis?
basale, spinosum, granulosum, lucidum, corneum
What is vitamin d required for?
calcium absorption
malignant melanoma
cancer of melanocytes
The epidermis receives nutrients and oxygen from
capillary networks in the dermis
Which of the following best describes holocrine gland secretion
cell rupture and die to secrete their product
A surgical incision along tension lines
closes and heals with relatively little scarring
Which of the following is a characteristic of the epidermis
consists of keratinized stratified squamous epithelium
What type of burn affects all layers of the skin and causes blistering, swelling, and scarring?
third degree
