lecture 4 Integumentary system Flashcards
Describe the three layers of the skin
- Epidermis - Most superficial layer, made of epithelial tissue
- Dermis - Middle layer, made of connective tissue.
- Hypodermis - Deepest layer, not part of the integument, made of connective tissue.
Describe the size, thickness and functions of the integument.
•Size: 1.5-2 square meters covering the entire body. 7-8% of body weight. (largest body organ)
Thickness: 1.5-4 millimeters
Functions: protection, prevention of water loss, temperature regulation, immune defense, metabolic regulation, excretion, sensory reception
(remeber P P Times - P.P.T.I.M.E.S)
What structures are included in the integumentary system?
The integument or cutaneous layer consists of the skin, nails, hair, sweat glands, and sebaceous glands.
Name and briefly describe the 5 layers of the keratinized epidermis. Which are found in thick skin? Which are found in thin skin?
- Stratum Corneum - Apical layer, made of dead cells; top layer
- Stratum Lucidum - only found in thick skin(hands, knees, feet); second layer
- Stratum Granulosum - Form water tight barrier; 3rd layer
- Stratum Spinosum - “spiny” layer; 4th layer
- Stratum Basale - Divides to form the spinosum layer; bottom layer
Remember: Can Loud Girls Sing Bass (Corneum, lucidum, granulosum, spinosum, basale)
What is the location and function of keratinocytes found in the epidermis.
Make keratin (found in all 5 layers of the epidermis). Most abundant cell type in epidermis
What is the location and function of Epidermal dendritic cells found in the epidermis.
Found in stratum spinosum
Controls immune response
What is the location and function of Tactile cells (merkel cells) found in the epidermis.
Associated with senses(touch/pressure)
Can become malignant.
Found in stratum basale
What is the location and function of Melanocytes found in the epidermis.
Make melanin
Found in stratum basale
Explain how hemoglobin contributes to skin color.
Carries oxygen in the blood, can make the skin red(blushing). If unoxygenated can make skin tone more blue.
Explain how melanin contributes to skin color.
determines how tan or dark you are
Explain how carotene contributes to skin color.
Causes yellowing of skin, mainly if you eat way too much food with carotene in it.
Describe the structure of the dermis, including the cells and the extracellular matrix.
The dermis has two layers:
•Papillary layer - made of areolar connective tissue
Contains Dermal papillae
•Reticular layer - made of dense irregular connective tissue.
Vascular
Innervated
The papillary layer of the dermis is rich in blood vessels and sensory nerve endings. Therefore, what are its main functions?
Nourishment and sensation. Also to feed the epidermis with oxygen and blood, as well as to collect waste products.
Describe dermal papillae and epidermal ridges.
Dermal Papillae and epidermal ridges look like egg cartons stacked on top of each other, they function to increase the surface area between the layers which facilitates the exchange of nutrients and creates strong surface tension
The reticular layer of the dermis is thick and rich in collagen fibers. Therefore, what functions does this layer perform?
The reticular layer functions for support and strength of the skin and plays a role in the ability of the skin to stretch. The orientation of the collagen causes cleavage lines.
What structures are typically found in the reticular layer?
Structures - glands, hair follicles, capillaries, veins, blood vessels
Describe the structure and functions of the hypodermis (subcutaneous tissue).
Structure: areolar and adipose connective tissue
Function: anchors skin to underlying structures, thermal insulation, energy reserves
** not considered part of integumentary system
Describe the basic structure of nails.
- nail matrix (on the inside)
- cuticle (skin on nail)
- lunula (proximal end of nail. whitish from blood vessels being obscured by thickened underlying stratum basale)
- free edge white ends of nails
Nail root, body, and free edge make up nail plate.
Describe the basic structure of hair.
- follicle, root and shaft
- contains keratin
- arrector pili muscle (contracts and causes goose bumps)
Describe the basic function of hair.
protection, sense touch, reduce heat loss
Describe the 3 basic types of hair.
Lanugo (fetal)
Vellus (fine hair on most of the body)
Terminal (head, pubic region, armpit, male facial hair)
Describe the basic growth cycle of hair.
- rate of hair growth is about 2 mm/ week
- growth cycles: active phase (2-7 years) dormant phase (3-4 months)
Compare and contrast the following glands in terms of basic structure, location in skin layers, location on the body, what is secreted, and function of the secretion.
Merocrine sweat glands
apocrine sweat glands
sebaceous (oil) glands
Glands of the Skin:
Sebaceous (oil) Glands:
- Associated with hair follicles
- Produce lipid material called sebum, which coats epidermis and shaft of hair; provide lubrication and antibacterial activity
Sudoriferous (Sweat) Glands:
Apocrine glands :
-Distributed in axillary, anal, areolar, and pubic regions
-Produces viscous, complex secretion; secretion influenced by hormones; may act in signaling/communication
Merocrine glands:
- Distributed throughout body, except external genitalia, nipples, and lips; especially prevalent on palms, soles, and forehead
- Produce nonviscous, watery secretion; controlled by nervous system; provide some antibacterial protection; function in thermoregulation and excretion; flush surface of epidermis
What is a first degree burn
only epidermis is damaged. Redness, pain, and slight edema (swelling). Mild sunburn
