Skin and Appendages Flashcards
What is the integumentary system?
What does it consist of?
Integument is the skin (organ: made up of different tissues)
Consists of the skin and appendages
What are seven functions of the skin?
- Protects
- Synthesis of vitamin D and UV
- Regulates body temperature
- Prevents unnecessary water loss
- Sensory reception
- Excretion
- Blood reservoir
What are the two types of skin?
What is its classification dependent on?
- Thin skin
- Thick skin
Dependent on thickness of the epidermis
What are the two main layers of the skin?
- Epidermis
2. Dermis
What are the five layers of the dermis, from deepest (1st layer) to superficial (5th layer)?
1st stratum basale (germinativium) 2nd stratum spinosum 3rd stratum granulosum 4th stratum lucidum 5th stratum corneum
What are the different types of cells contained in the dermis?
- stratified squamous keratinized epithelium
- melanocytes
- keratinocytes
- merkel
- langerhans
Describe layer 1 of the epidermis.
Name? Cells contained? Function?
Stratum basale (germinativium)
single layer of cubodial or columar keratinocytes on basement membrane
melanocytes- brown pigment melanin, found on superficial layer of keratinocytes
merkel cells- sensory nerve endings
Describe layer 2 of epidermis.
Name? Cells contained? Function?
Stratum spinosum
8-10 layers of polyhedral cells, cells contain protein cytokeratin
separated by narrow translucent clefts
spine like cytoplasmic extensions connect from one cell to next by desmosomes
contain Langerhans cells- act as macrophages
Describe layer 3 of epidermis.
Name? Cells contained? Function?
Stratum granulosum
cells become flat 3-5 cells
contain basophilic keratohyaline granules
cellular organs begin to disintegrate
Describe layer 4 of epidermis.
Name? Cells contained? Function
Stratum lucidum
several layers of clear flat dead cells
faint nuclear outline in some cells
protein eleidin intermediate keratin
only found in thick skin
Describe layer 5 of epidermis.
Name? Cells contained? function?
Stratum corneum
30 cells thick , 3/4 of epidermis
cells shed regularly, looser appearance
individual cells difficult to observe
What is the dermis? Cells contained? Fibers contained?
strong, flexible connective tissue layer
cells: macrophages, mast cells, white blood cells, fibroblasts
fibres: collage, elastic, recticular
What are the two layers of the dermis?
- Papillary
2. Recticular
What is the Papillary layer of dermis?
Extends into epidermis
1/5 of dermis
highly vascular
forms dermal papillae: fingerprints
What is the Reticular layer of the dermis?
irregular dense connective tissue
contains: hair follicles arrector pili muscles sebaceous glands sweat glands Meissner's corpuscle Pacinian corpuscle
What is the hypodermis?
superficial fascia
fatty tissue that stores fat and oils
areolar and adipose tissue
What are skin appendages? Examples?
derived from epidermis but extend to dermis
include: hair/hair follicle
sebaceous oil glands
sweat glands
nails
What is hair pili?
Composed of dead columns of keratinized cells
Two parts: shaft & root
consists of medulla, cortex(keratin and pigments), outer cuticle
Hair?
Root hair in epidermal tube (root follicle) extending into dermis
Hair bulb: dilation at base
dermal papilla: invigilates into bulb, contains blood capillaries
arrector pili muscle extends from deep part of hair follicle to papillary layer, supplied by sympathetic nerves= contraction
Sebaceous oil glands?
dermis of thin skin
opens into upper portion of hair follicle
produces sebum by holocrine secretion
oils and lubricates
Sweat glands?
aka sudoriferous
prevents overheating, produced in response to heat or stress
has acinus lined by columnar cells
found in entire skin surface
What are the three types of sweat glands?
- Eccrine or merocrine
- Apocrine
- Modified apocrine glands
What are eccrine or merocrine glands?
most numerous, open through pores
What are apocrine glands?
ducts open into hair follicles
organic molecules decompose with time = odor
What are modified apocrine glands?
ceruminous- secrete ear wax
mammary- secrete milk
