The Integumentary System Flashcards
The integument (latin integumentum = to cover)
-Ranges between 1.5- 2.0 meters
-Accounts for 12%-20% of the body weight
-Ranges between 1.5 and 4 millimeters
Also known as the cutaneous membrane or cutaneous layer
Integumentary System
Covers the surface of the body and its specialized structures include hair, nails, sweat glands, mammary glands, and teeth
Functions of the Skin
- Protection: of the body from environmental effects
- Containment: for the body’s structures and vital substances
- Preventing dehydration: by limiting fluid loss
- Heat Regulation: through the evaporation of sweat and/or the dilation or constriction of superficial blood vessels
- Sensation: by way of superficial nerves and their sensory nerves and their sensory nerve endings
- Synthesis and storage of vitamin D
Structure of The Integumentary System
- Epidermis: Stratified squamous epithelium and basement membrane
- Dermis: loose connective tissue and dense irregular connective tissue
- Accessory Structures: hair, glands, nails
Burns
Classified into 6 separate groups: Scalds, contact burns, fire, chemical, electrical, radiation
Rules of Nine: Total body surface area
Head: 9% Trunk: 36% Arms: 18% Thighs: 18% Lower legs and feet: 18% Genital region: 1%
Jaundice
Condition in which the skin, sclera, and mucous membranes turn yellow caused by a high level of bilirubin due to the breakdown of red blood cells
Germ Layer Origins
Ectoderm: Forms the surface of the epidermis and the associated glands
Mesoderm: Somite origin- forms the underlying connective tissue of dermis and hypodermis
Neural crest cells: Migrate into the forming epidermis and the skin is also populated by specialized sensory endings
Epidermis- Week 4
Embryo is covered by a single layer of ectodermal cells
Epidermis- Week 5
In the beginning of the second month, this epithelium divides and a layer of flattened cells, the periderm, or epitrichium
Epidermis- Periderm Layer
The cells of the periderm layer continually undergo kerantinization and desquamation to be replaced by cells arising from the basal layer and replacement of the peridermal cells continues until about week 21 and thereafter the periderm normally disappears
Epidermis- Week 11
By week 11, the basal layer forms an intermediate skin layer
Epidermis- End of the 4th Month
All the epithelial layers of the adult epidermis of skin have acquired their definitive arrangement
Melanocytes
During the first 3 months of development, neural crest cells migrates and invades teh epidermis to form melanoblasts and then melanocytes by WNT Signalign regulation
Dermal Papillae
The superficial dermal layer or corium projects upward into the epidermis and forms the dermal papillae
Appendages- Hair
Begin to develop during the #rd month, but they do not become visible until the 20th week
Begins as an epidermal proliferation, the hair bud, into the underlying dermis
The central epihelial cells of the hair bulb give rise to the shaft of the hair that growns through the epidermis and protuders above the surface of the skin
Appendages- Sweat Glands
Develop at about 20 weeks as solid growth of epidermal cells into the underlying dermis. They develop as down-growths of the stratum germinativum of the epidermis
Vernix Caseosa
Vernix caseosa, is the waxy or cheesy white substance found coating the skin of the newborn
Appendages- Nails
Begin to develop at about 10th week of gestation as thickened areas of the epidermis at the tips of the digits
Mammary Glands
Develop during the 6th week as thickened strips of the ectoderm that extend from the axillary to the inguinal regions
Teeth
The teeth develop from ectoderm and mesoderm: The enamel develops from ectoderm of the oral cavity and all other tissues come from the associated mesenchyme
Fasciae
Fascia is the soft tissue component of the connective tissue system that permeates the human body
Ligaments
A tough cord or fibrous band of connective tissue that binds bone to bone or supports viscera
Tendons
A band of dense regular connective tissue that attaches muscle to bone
Retinaculae
Several fibrous bands of fascia that pass over or under tendons
joint capsules
The fibrous tissue that encloses the joint cavity of a synovial joint
Organ and Vessel Tunics
Membranes or other structures covering or lining a body part or organ
The Epineurium
A fibrous outer sheath of connective tissue surrounding a nerve
The meninges
A group of three fibrous membranes covering the central nervous system
The periostea
A fibrous connective tissue covering the outer surface of bone
Myofasciae
Layer of loose but strong connective tissue often containing fat covering and investing all muscles
Serosa
Parietal serosa- lines internal body walls
Visceral serosa- covers the internal organs
Dorsal cavity
Protects the nervous system and is divided into two subdivisions: Cranial cavity- within the skull and encases the brain
Vertebral cavity: within the vertebral column and encases the spinal cord
Ventral Cavity
houses the internal organs and is divided into two subdivisions:
Thoracic cavity- houses heart and lungs; Abdominopelvic cavities- houses the abdominal viscera and the urogenital viscera
Oral and digestive
mouth and cavities of the digestive organs
Nasal
located within and posterior to the nose
Orbital
house the eyes
Middle ear
contain bones that transmit sound vibrations
Synovial
joint cavities
