Integumentary System Flashcards
What organ system consists of the skin, hair, nails, and exocrine glands?
Integumentary system
What is the function of the exocrine glands of the integumentary system?
Produce sweat, oil, and wax to cool, protect, and moisturize the skins surface
What are the functions of the integumentary system?
- Protection against assaults from ultraviolet light and other mechanical, chemical and thermal agents
- Provides a natural barrier against microorganisms
- Prevents dehydration by reducing evaporation
- Waterproofing
- Reception of sensory information through receptors for touch, pressure, pain and temperature
- Regulation of heat gain or loss
- Supplying triglycerides- a major source of energy (hypodermis underneath the dermis)
- Synthesis of vitamin D (absorption of calcium in the kidneys)
What is the largest organ if the body?
Skin
What are the 2 main layers of the skin?
Epidermis
Dermis
What layer lies under the dermis?
Hypodermis or Subcutaneous tissue
Not actually part of the skin but serves as an anchor
What tissue makes up the epidermis?
Consists of stratified squamous keratinized epithelium.
Describe the dermis layer of the skin:
Thick layer of fibro-elastic connective tissue
Highly vascular, provides a source of nourishment to the epidermis
Receptor organs present
What are the two layers of connective tissue, interwoven with one another that form the dermis?
The papillary dermis
The reticular dermis
What is the subcutaneous layer of the skin made of?
Layers of loose connective tissue containing various amounts of adipose (fatty) tissue.
What are the layers of cells in the thick skin? from superficial to deep
Stratum corneum
stratum lucidum
stratum granulosum
stratum spinosum, stratum basale
What are the cells in the Stratum corneum, stratum lucidum, stratum granulosum, and stratum spinosum called?
keratinocytes
What is a keratinocyte?
An epidermal cell that manufactures and stores the protein keratin
What is keratin?
Intracellular fibrous protein that gives hair, nails, and skin their hardness and water-resistant properties.
What cell is found in the stratum basale?
melanocytes
What is the function of melanocytes?
Produce the pigment melanin
Gives hair and skin its colour and helps to protect the living cells of the epidermis from UV radiation damage
What are the 2 layers of the dermis?
The papillary dermis
The reticular dermis
What are the touch receptors in the papillary dermis?
Meissner corpuscles
What makes up the papillary dermis?
loose, areolar connective tissue
collagen and elastin fibers of this layer form a loose mesh
What makes up the reticular dermis?
thicker than papillary dermis
composed of dense, irregular connective tissue
Describe the hypodermis?
- Directly below the dermis and serves to connect the skin to the underlying fascia (fibrous tissue)
- Not strictly a part of the skin
- Well-vascularized, loose, areolar connective tissue and adipose tissue, which functions as a mode of fat storage and provides insulation and cushioning for the integument
- Connects to underlining muscle and bone
Describe lipid storage:
- Adipose tissue present in the hypodermis consists of fat-storing adipocytes
- Serves as an energy reserve
- Insulates the body to prevent heat loss
- Cushion to protect underlying structures from trauma
what are the Integumentary system accessory structures?
Accessory structures of the skin include hair, nails, sweat glands, and sebaceous glands.
Hair and nails are modified forms of stratum corneum
Describe hair:
keratinous filament growing out of the epidermis
Strands of hair originate in an epidermal invagination of the dermis called the hair follicle
At the bottom of the follicle - hair papilla lined with stratum germinativum (germinal matrix) which produces the hair
Hair bulb surrounds the papilla containing capillaries and nerve endings from the dermis
what is the function of hair?
Protection
Sensory input
Thermoregulation
Communication
What is the function of Sebaceous glands?
Exocrine gland attached to hair follicle
Produces sebum: fatty/oily substance that coats the hair and skin
Natural lubrication
Prevents moisture loss and pliability (prevents hair from becoming brittle)
fatty acids of sebum also have antibacterial properties
secretion of sebum is stimulated by hormones
What glands are relatively inactive during childhood?
sebaceous glands
What is the function of sweat glands?
Exocrine sudoriferous glands produce sweat to cool the body
Develop from epidermal projections into the dermis and are classified as merocrine glands
What are the 2 types of sweat glands?
Eccrine Sweat Glands & Apocrine Sweat Gland
How is sweat secreted?
Excreted by exocytosis through a duct without affecting the cells of the gland
Describe eccrine sweat glands:
Produces a hypotonic sweat for thermoregulation
Found all over the skin’s surface
Especially abundant on the palms of the hand, the soles of the feet, and the forehead
Hypotonic and composed mostly of water, with some salt, antibodies, traces of metabolic waste, and dermicidin, an antimicrobial peptide
Primary component of thermoregulation in humans, helps to maintain homeostasis
Describe apocrine sweat galnds:
Associated with hair follicles in densely hairy areas, such as armpits and genital regions
larger than eccrine sweat glands and lie deeper in the dermis, sometimes even reaching the hypodermis
Duct normally emptying into the hair follicle
Apocrine sweat includes organic compounds that make the sweat thicker and subject to bacterial decomposition and subsequent smell
Describe nails and their function:
Specialized structure of the epidermis that is found at the tips of our fingers and toes
Nail body is formed on the nail bed, and protects the tips of our fingers and toes as they are the farthest extremities and the parts of the body that experience the maximum mechanical stress
Nail body is composed of densely packed dead keratinocytes
Nail body forms at the nail root, which has a matrix of proliferating cells from the stratum basale that enables the nail to grow continuously
What layer of the human skin synthesizes vitamin D when exposed to UV radiation?
epidermal layer
Describe the Vitamin D synthesis process?
In the presence of sunlight, a form of vitamin D3 called cholecalciferol is synthesized from a derivative of the steroid cholesterol in the skin
Liver converts cholecalciferol to calcidiol, which is then converted to calcitriol (the active chemical form of the vitamin) in the kidneys
What is Basal Cell Carcinoma?
Form of cancer that affects the mitotically active stem cells in the stratum basale of the epidermis
Most common skin cancer that occurs and is frequently found on the head, neck, arms, and back, which are areas that are most susceptible to long-term sun exposure
Start in the stratum basale and usually spread along this boundary
What is Squamous Cell Carcinoma?
Affects the keratinocytes of the stratum spinosum and presents as lesions commonly found on the scalp, ears, and hands
Second most common skin cancer
More aggressive than basal cell carcinoma, can metastasize
What is melanoma?
Uncontrolled growth of melanocytes
Typically develops from a mole
Most fatal of all skin cancers
Highly metastatic and can be difficult to detect before it has spread to other organs
Appear as asymmetrical brown and black patches with uneven borders and a raised surface
Describe the steps of identifying melanoma:
Asymmetry: the two sides are not symmetrical
Borders:the edges are irregular in shape
Color:the color is varied shades of brown or black
Diameter:it is larger than 6 mm (0.24 in)
Evolving: its shape has changed
