Skin Anatomy Flashcards
What are the 5 functions of the skin?
- Protection
- Thermoregulation
- Excretion of sweat
- Vitamin D synthesis
- Sensory reception
What are the 3 layers of the skin?
- Epidermis (of ectoderm origin)
- Dermis (of mesoderm origin)
- Hypodermis (subcut tissue or superficial fascia - connective tissue)
What epithelium is the epidermis composed of?
- Stratified squamous keratinised epithelium
What are the 5 layers of keratinocytes?
- Stratum basale/germinativum (stem cell)
- Stratum spinosum (prickle cell)
- Stratum granulosum (Keratohyalin granules)
- Stratum lucidum (thick skin)
- Stratum corneum (Cornified layer)
What is 1 in every 10 keratinocyte cells?
Melanocyte - pigment producing cell
Label the cells of the skin
Where are the langerhans cells and what do they do?
- Found in the stratum spinosum layer
- Antigen presenting cells for T cells
What are the 2 layers of the dermis?
- Papillary layer - loose connective tissue
- Reticular layer - dense irregular connective tissue
How is the papillary layer of the dermis attached to the epithelium?
- Dermal papillae that interdigitate with epidermal (rete) ridges
How does epidermis get its blood supply?
- Epidermis doesnt have it’s own blood supply
- relies on diffusion from dermis
What makes up your fingerprint?
The papillae in the dermis going up and down
Label the layers of the skin
What is the hypodermis made up of?
- Primarily adipose tissue segregated by loost connective tissue
What does the hypodermis attach?
- Attaches the skin to underlying structures and allow its free movement
What is the function of hypodermis?
Insulates the body and provides energy storage
Does the hypodermis contain a blood supply?
Yes:
Contains major vessels, nerves, some nerve endings and terminal parts of the skin appendages
What are 3 skin appendages?
- Hair and follicles
- Glands (sweat and sebaceous)
- Nails
Define:
1. Hair follicle
2. Hair bulb
3. Hair
- HF is a downgrowth of the epidermis (may extend to hypodermis)
- HB is the terminal dilation of the hair follicle, consits of: matrix cells surrounding a hair (dermal papilla)
- Keratinized outgrowth of the hair follicle
What is the muscle that moves the hair?
Errector pili (goosebumps = contraction to make the hair standup)
What is the:
* Frequency
* Structure
* Function
of the
1. Eccrine glands
2. Apocrine glands
- Abundant
* Coiled tubular glands, distal secretory part, narrow duct
* Role in thermoregulation, protection & excretion - Limited to the areola, axilla, anal and external genital regions
* Coiled tubular glands, wider lumen, branched and open into the hair follicles
* Become functional at puberty, secretion is pheremone
- What are sebaceous glands and where are they found?
- What do they produce
- Function?
- Branched acinar glands located between the hair follicle and arrector pili musle
- Produces sebum
- Waterproofing and protection
What does blockage or inflammation of sebaceous glands result in?
Acne
What are the nails composed of?
- Nail plate - several layers of dead compacted cells
- Nail bed - beneath nail plate - comprises dermis and epidermis
- Many nerves and vessels
What are the 2 types of nerve endings?
- Non-encapsulated
- Encapsulated
- Where are non-encapsulated nerve endings found?
- What do they do?
- In epidermis between keratinocytes or attached to merkel cells
* In the dermis around the hair follicles - In merkel cells detect pain, heat, cold, fine and discriminative touch
* In the dermis detects hair displacement
- What are the 2 types of encapsulated nerve endings and where are they found, what do they detect?
- Pacinian corpuscles (hypodermis) detect pressure and vibration
- Meissner’s corpuscles (dermis) detect light touch
What do sympathetic motor efferent nerve endings supply?
- Vascular smooth muscle
- Arrector pili muscles
- Sweat glands
What do the sympathetic sensory nerve endings supply?
- Carry sensation to the CNS
