Integumentary System Flashcards
What covers the entire surface of the body and is the largest organ of the body in terms of its weight and volume?
Integumentary system, or skin
What are some accessory structures of the skin
Hair
Nails
Glands
What are the 3 types of glands?
- sebaceous
- eccrine sweat
- apocrine
What are the tissues that the skin is made up of?
- epithelium
- connective tissue
- muscles
- blood vessels
- nervous tissue
Functions of the skin
- protection
- prevention
- regulation
- sensation
- immunological function
- production of vit D
Function of skin: protection
-protects body from invasion of pathogens, prevention of tissue damage by toxic chemicals and UV light
Functions of skin: prevention
Of dehydration and loss of body fluids (impermeable to water)
Functions of skin: regulation
Of body temperature (production and excretion of sweat, vascular shunts)
Function of skin: sensation
Sensation of touch, pain, temperature, pressure, and vibration; important for communication, dexterity, and injury prevention
Function of skin: immunological function
Langerhans cells (antigen-presenting cells) present antigens to lymphocytes in the immune response
Functions of skin: production of vit D
Production of vit D from precursors under the effects of steroids and sunlight
What are the two divisions of the skin?
Epidermis and dermis
__________ is a maximally keratinized stratified squamous epithelium
Epidermis
Epidermis is composed of five named layers of cells called _____________
Keratinocytes
What is the only layers that have blood vessels and nerves?
Dermis
What is the deepest layer of the epidermis?
Stratum basale
________ is a single layer of cuboidal or tall cuboidal cells that lies on the basement membrane.
Stratum basale
Many of the cells of the stratum basale are what?
Stem cells that actively divide and give rise to the cells in the other four layers
What of the stratum basale is renewed constantly?
Epidermal keratinocytes. The top layer of cells continually being shed and new cells from the stratum basale replacing them.
It takes about _________ for keratinocytes to finish their renewal cycle
3-4 weeks
Layers of the epidermis from deep to superficial
- Stratum basale
- Stratum spinosum
- Stratum granulosum
- Stratum lucidum
- Stratum corneal
In addition to keratinocyte stem cells, what are the other two special types of cells in the stratum basale?
Melanocytes and merkel cells
Melanin producing cells which are in contact with the keratinocytes that are located immediately above the stratum basale
Melanocytes
Stratum basale
Sensory receptor cells which respond to continuous touch stimuli
Merkel cells
Stratum basale
_________ contains polyhedral keratinocytes, which become more flattened in the superficial part of this layer.
Stratum spinosum
What layer is responsible for the water proof nature of skin?
Stratum spinosum
The plasma membrane of the stratum spinosum of neighboring cells is connected by ______________
Desmosomes (macula adherens)
______________ (modified macrophages) are an additional cell type often found in the stratum spinosum
Langerhans cells
What layer of epidermis protects against infection?
Stratum spinosum
_______________ contains keratinocytes which are flattened cells with kerato-hyaline granules in their cytoplasm
Stratum granulosum
What layer of the epidermis is more prominent in the thick skin than the thin skin?
Stratum granulosum
What are basophils in appearance in H&E stained sections in the stratum granulosum?
Kerato-hyalin granules
__________ is a thin layer that us only found in the thick skin
Stratum lucidum
What does the stratum lucidum contain?
A few layers of flattened cells, which are densely packed together and lie beneath the stratum corneum. Their nuclei become pycnotic (shriveled) as they being to degenerate
What is the extended part of thick skin that hasn’t died just yet, but starting to.
Stratum lucidum
__________ is the most superficial layer, which contains numerous extremely flattened cells completely filled with keratin.
Stratum corneum
Cells of the stratum corneum contain no _____________ and are technically dead cells. The cells on the surface are continuously shed.
No nuclei or organelles
___________ is a connective tissue layer deep to the epidermis.
The dermis
What is contained within the dermis?
Blood vessels, nerves, and afferent sensory receptors
What are some of the afferent sensory receptors in the dermis
Meissner corpuscles and free nerve endings
___________ is a transition (subcutaneous) layer below the dermis of the skin.
Hypodermis
What does the hypodermis contain
Loose connective tissue, adipose tissue, nerves, arteries, and veins
Cells in the stratum corneum
Horny cells (dead cells)
Cells in the stratum lucidum
Flattened keratinocyte
Cells of stratum granulosum
Keratinocyte with keratohyalin granules
Cells of the stratum spinosum
Langerhans cell
Keratinocyte
Cells of the stratum basale
Merkel cell
Melanocyte
__________has a thick epidermis (400-600 micrometers) with five distinct cell layers
Thick skin
What layer is extrmely thick in thick skin?
Stratum corneum
What does thick skin cover?
Palms of the hands and soles of the feet
Thick skin has abundant _________ glands
Eccrine sweat
Thick skin lacks ________
Hair follicles
The epidermis is a ____________ epithelium
Stratified squamous
How are nutrients delivered to the thick skin?
By fluid diffusion from the dermis
Thick skin dermis is composed of what?
- superficial papillary layer
- reticular layer
Papillary layer of the thick skin
Layer of loose connective tissue
Deep reticular layer of thick skin
Thick layer of dense irregular connective tissue
What layer are the meissner corpuscles in?
Dermis
The portion of the epidermis that projects into the dermis is termed the ___________
Epidermal rate ridge
Portion of the dermis that projects into the epidermis is called the _______
Dermal papilla
What is special about the meissner corpuscle and the epidermal rete ridge?
Increases the contact area between these two layers, preventing the epidermis from detaching from the dermis.
What does the dermal papilla contain?
Loose connective tissue that includes many capillaries, free nerve endings, and encapsulated sensory receptors.
what does thin skin cover?
The entire body surface except the palms of the hands and the soles of the feet
Why does thin skin have a thin epidermis?
Largely because its stratum corneum is much reduced compared to that of thick skin
What does thin skin have that thick skin doesn’t?
Hair follicles and their associated sebaceous glands
What responds to vibration stimuli?
Pacinian corpuscles
Where are the pacinian corpuscles found?
In the hypodermis of both thin and thick skin. They are found in many regions of the body but are more numerous in the tips of the fingers and toes than in other areas
Meissner in thin skin
Fewer in thin skin
____________ is a layer of loose connective tissue, which contains adipose tisssue, nerves, arteries, and veins
Hypodermis
What does the hypodermis serve as for the dermis?
Serves as a transition layer, providing the dermis with a flexible attachment to the underlying muscles and other structures
Found in the dermis. Sensitive to fine touch, mainly found in thick skin
Meissner corpuscles
Found in the hypodermis on the border with the dermis. Sensitive to vibrations, found in both thick and thin skin but more prominent in thick skin
Pacinian corpuscles
_________ has barely any stratum corneum
Thin skin
The ___________ gets its name from the many small processes that seem to join neighboring cells with one another
Stratum spinosum
Each cell is joined to its neighbors by ________________
Numerous maculae adherens (desmosomes)
Function of stratum spinosum
Establishing tough, impermeable barrier layer at the surface of the skin
Clear cells
Melanocytes, merkel cells, and langerhans cells. Have clear cytoplasm. No keratin
Where are melanocytes and merkel cells found?
Both located in the stratum basale where they are scattered among the basal cuboidal cells
Langerhans cells are typically found in the __________
Stratum spinosum
Produce melanin granules and insert them into keratinocytes
Melanocytes
Receptor cells, that established synaptic contacts with sensory nerve terminals. They have cytoplasmic granules, which contain neurotransmitters
Merkel cells
Monocytes derivative, which play an important role in capturing antigens and presenting them to lymphocytes, thereby participating in the cutaneous immune response. These cells are not connected and are mobile so they can transport antigens to the lymph system
Langerhans cells
Bee stings, poison ivy
Differences of thick and thin skin epidermis
Thick-5 layers, thick stratum corneum, thick stratum granulosum
Thin-4 layers, no stratum lucidum, single layer of or no stratum granulosum
Which type of skin has hair follicles?
Thin skin, in most places
Types of glands in thick skin
Lack of sebaceous glands, more eccrine sweat glands
Glands in thin skin
Sebaceous glands, fewer eccrine sweat glands
Which has more receptors, thick or thin skin?
Thick
Special feature of thick skin
Thick epidermis; thick stratum corneum, stratum lucidum present; several cell layers stratum granulosum
Special feature of thin skin
Thin epidermis; thin stratum corneum, stratum lucidum absent; one layer or no stratum granulosum
Types of glands found in the skin
- Sebaceous
- Eccrine
- Apocine
_________ are found in thin skin, usually associated with hair follicles
Sebaceous glands
Where are the sebaceous glands more numerous in the skin of the __________
Scalp and face
Sebaceous glands secretion
Empty their oily secretion, called sebum, into a hair follicle
How do sebaceous glands release their products?
Holocene secretion
Disintegration of entire cells
Holocene secretion
________ lubricates the skin and coats and protects hair shafts from becoming brittle
Sebum
Where are eccrine (merocrine) sweat glands found?
Thin and thick skin over most of the body
Where are eccrine sweat glands more numerous?
Palms and soles of feet
What do eccrine sweat glands produce?
A clear watery product called sweat
What does sweat contain?
Water, ions, waste, and metabolic products
What does sweat do?
Adjust body temperature as well as waiting in the excretion of metabolic wastes
What is the difference between the structure of a province sweat glands and eccrine sweat glands?
Apocrine have larger lumens
Where do the apocrine sweat glands empty into?
Superficial regions of the hair follicles.
How do the secretory cells of the apocrine glands release their products
By shedding part of their apical cytoplasm; this is called apical secretion
Restricted in location to some specific regions of thin skin, such as the axilla, the areola, and the perianal and genital areas
Sexual scent glands (aprocrine)
Have an axillary body odor after degradation by bacteria
What are some accessory structures of the integumentary system?
Hair and nails
