W6 Integument System Flashcards
What is the integumentary system composed of?
Skin and it’s accessory structures: hair, nails, various types of glands, and sensory receptors
List the functions of skin
Regulate body temp Protective barrier between external environment Contains nerve endings Help synthesis vitamin D
Name the tissue type composing the epithelial tissue
Epidermis Dermis
Define epidermis
Superficial thinner layer, composed of epithelial tissue
Define Dermis
A deeper, thicker portion. It is compose of connective tissue
Define Hypo Dermis
Is ocmposed of areolar and adipose tissue. THE HYPO DERMIS IS NOT APART OF THE SKIN
What are the functions of the hypodermis
Fibres act to anchor the skin to the hypodermis, fat storage
What are the two major types of skin?
Thin skin Thick skin
Describe the structure of thin skin
Has a thin epidermis. It contains hair sebaceous (oil) glands, but fewer (sudoriferous (sweat) glands than thick skin
Where is thin skin found?
Covers all parts of the body except the palms, palmar surface of fingers, planta surface of toes, and sole of feet
Describe the structure of thicl skin
Has a thick epidermis. Lacks hair and sebaceous (oil) glands, but has more sudoriferous (sweat glands) than thin skin
Where is thick skin found?
Covers the palms, palmer surface of fingers, plantar surface of toes, and soles
What is the epidermis composed of?
Keratinized stratified squamous epithelium
Name the 4 cell types that the epidermis is composed of
Keratinocytes Melanocytes Langerhans Cells Merkel Cells
Describe Keratinocytes
Most numerous cell type, They produce keratin, which is a tough, fibrous protein that helps protect the cells and underlying tissues. Also produced lamellar granules (waterproofing)
Describe Melanocytes
Are located in the deepest layer of the epidermis. These cells produce melanin
Describe Langerhans Cell
Make up only a small fraction of epidermal cells. They perform immune function, by fighting microbes
Describe Merkel Cells
Least numerous of all cells in the epidermis. Located deep in the epidermis and form touch receptors
What are the four cellular strata found in thin skin?
Stratum basale Stratum spinosum Stratum Granulosum Stratum Corneum
Describe Stratum basale
A single row of cuboidal keratinocytes, this layer also contains melanocytes
Describe Stratum Spinosum
Layers more towards the surface, have a more flattened appearance
Describe Stratum Granulosum
These cells undergo apoptosis. Flattened keratinocytes
Describe Stratum Corneum
Composed of 25-30 layers of dead flattened keratinocytes. Continually shed and replaced by cells from a deeper layer
PICWhat are the 5 cellular strata found in thick skin?
Stratum Lucidum Contains the same cellular strata as thin, with an extra layer
How does epidermal growth proceed?
Cells that have been newly formed in the stratum basale are gradually pushed to the surface of the epidermis (stratum corneum) called keratinization. Takes 4 weeks
What is the dermis composed of?
Connective tissue containing collagen and elastic fibers + blood vessels, nerves, glans, and hair follicles
Name the 2 regions of which the dermis can be divided into
The papillary region - directly underneath the epidermis The reticular region - located below the papillary region
What is the papillary region composed of?
Areolar connective tissue containing elastic fibers
What are dermal papillae?
The presence of finger like projections
What are epidermal ridges?
Downward projections of the epidermis
How do epidermal ridges and dermal papillae interact?
Join together to form a very strong connection, helps resist shearing forces that could separate the epidermis from the dermis
Describe the recticular region
It is attached to the hypodermis, composed of dense irregular connective tissue containing bundles of collagen fibers. Gives skin extensibility and elasticity
What is the reticular region composed of?
Hair follicles, nerves, sebaceous (oil) glands, and sudoriferous (sweat) glands
What are the tree pigments that give skin its colour?
Melanin, Carotene, Haemoglobin
What is a influencing factor in skin colour?
Heredity, major factor in melatin production
Describe ways in which the integument system protects the body
Physcal barrier to microorganisms Barrier to chemicals Reduces potential for mechanical trauma Protects against excess UV exposure
Describe protection - surface film on the skin
Antibacterial, antifungal activity Lubrication Hydration of skin surface
Name chemical composition of epithelial elements of surface film
Amino acids Sterols Complex phospholipids
Name chemical composition from the sebum on surface film
Fatty acids Triglycerides Waxes
Name chemical composition from sweat on the surface film
Water Ammonia Lactic Acid
What are the functions of the Skin?
Sensation, flexibility, excretion
List the sensations detected by the skin
Heat Gentle touch Pain Cold Hair
List the glands involved in secretion
Eccrine glands Apocrine gland Sebaceous gland Ceruminous gland
Describe the Eccrine Gland
Most numerous sweat glands, secrete perspiration
Describe Apocrine gland
Located deep in subcutaneous layer, large
Describe Sebaceous glands
Secrete sebum
Describe Ceruminous glands
Modified apocrine sweat gland, located in ear
What is the skins role in absorption?
Substances can enter the body through the skin
Describe the integuments involvement in vitamin product
Exposure of sin to UV light converts to Vit D precursor, blood transport the precursor to the liver and kidneys. The process and end result fulfill the steps required to classify vit D
Name the immune cells that reside in the integument and describe their fuction
Phagocytic cells destroy bacteria. Resident dendritic cells in the skin known as Langerhans cells, these act as antigen presenting cells, showing antigen to lympohocytes. Dendritic cells trigger helpful immune reactions by working with helper t-cells
Explain how the skin helps cool the body or retain warmth
Homeostasis of temperature Heat production amount of muscular work being performed. Heath loss: to evaporate any fluid, heat energy much be expended
What are the mechanisms of heat loss
- Radiation
- Conduction
- Convection
PICDescribe radiation
Transfer of heat from one object to another without actual contact
Describe conduction
Transfer of heat to any substance actually in contact with the body
Describe convection
Transfer of heat anyway from a surface by movement of air
How is heat loss regulated?
Controlled by negative feed back loop -> receptors in the hypothalamus
Explain the development of hair
Distribution: over entire body except palms Lanugo: fine, soft hair coat Terminal hair: coarse public hair Hair follicles
