Integumentary System Flashcards
Epidermis?
- Superficial, thinner portion composed of epithelial tissue.
Dermis?
- Deeper, thicker portion, composed of dense irregular connective tissue.
Hypodermis?
Deep to dermis but not part of skin is subcutaneous (hypodermis).
Epidermis contains 4 types of cells?
- Keratinocytes: Produce keratin. Protects cells, maintains elasticity,
- Melanocytes: Produce melanin. Melanin protects skin by shielding from the sun.
- Intraepidermal macrophages- Immune response.
- Tactile epithelial cells: Detect touch sensations.
Lamellar granules?
Present in keratinocyte.
Release lipid rich secretion that acts as a water repellent sent, holding back loss of water.
Newly formed cells in the stratum basale are?
Slowly pushed to surface.
More and more kertain accumulation is called?
Keratinisation.
Epidermis has 4 layers?
- Stratum corneum- Most superficial layer.
- Stratum granulosum- Keratinocytes undergo apoptosis here.
- Stratum spinosum- Provides strength and flexibility.
- Stratum basale- Deepest layer.
Palms and soles have one extra layer- Stratum Lucidum.
Dermis?
- Superficial layer is called papillary layer.
- Consists of:
Areolar (contains elastic fibres).
Dermal papillae with though receptors.
Capillary loops and sensory neurons.
Meissner corpuscle?
Type of touch receptor.
Found in dermal papillae.
Deepest part of dermis is called?
- Reticular layer.
- Consists of:
Dense irregular.
Elastic and collagen. - Function: Provide strength and flexibility.
Accessory structures of skin are?
- Hair.
- Nails.
- Glands.
Associated with hair are?
- Bundles of smooth muscle called arrector pili.
- Sebaceous glands or oil glands.
Colour of hair is due to?
Melanin.
- Grey hair occurs with decline in melanin.
- White hair results from accumulation of air bubbles in the hair shaft.
Glands?
Single or groups of epithelial cells that secrete a substance.
Sebaceous glands?
- Usually connected to hair follicles.
- Produce sebum which moistens hair and waterproofs skin.
Ceruminous glands?
Reduces risk of bacterial and fungal infection.
Located in ear canal, earwax.
Sudoriferous glands?
Secrete water and salt as sweat.
Helps lower body temperature.
Two types of sudoriferous glands?
- Apocrine: Found mainly in skin of armpit, groin etc.
- Eccrine: Most prevalent. Found in forehead, palms and soles.
Cell division of nail matrix cells produces?
New nails.
5 major functions of skin?
- Body temperature regulation- Release sweat to lower temperature.
2.?
Protection.
Keratin protects tissue form microbes and heat etc.
Lipids released by lamellar granules inhibit evaporation of water from skin surface.
3.?
Cutaneous sensations.
Touch, pressure, vibration and pain.
4.?
Excretion and absorption.
Skin has a small ability to absorb and excrete chemicals and toxins.
5.?
Synthesis if vitamin d.
Exposing skin to UV radiation activates vitamin d.
When there is damage to skin, cells begin to heal to restore homeostasis?
- Epidermal- Involves damage to epidermis only and stratum basale move into wound to reproduce and create new layers.
- Deep wound healing- Extends to epidermis and lower. Fibroblast lay down collagen and forms scar tissue.
Aging and integumentary system?
- Collagen fibres decrease in number and stiffen.
- Elastic fibres lose elasticity, thicken into clumps.
- Fibroblasts which produce both of the above decreasing number known as wrinkles.
- Less sebum and sweat.
- Hair thins may stop going.
- Slower skin healing.
3 common forms of skin cancer?
- Basal cell carcinoma. Tumours in stratum basale, rarely spread.
- Squamous cell carcinoma. Arise from stratum spinosum and may spread.
- Malignant melanoma. Arise from melanocytes.
Exposure to UV radiation may?
Produce photosensitivity, reaction of skin.
Burns?
1st- Only epidermis and mild pain, no blisters.
2nd- Damage epidermis and part of dermis, can cause blisters.
3rd- Damage epidermis and dermis and subcutaneous layer, most skin functions are lost.
Which is the only layer of the epidermis that contains stem cells capable of continued cell division?
Stratum basale.
Cuticle of the nail consists of?
Stratum corneum.
Arrector pilli contract in response to?
Stress like cold or fright.
