Integument Flashcards
1
Q
Integumentary system - functions
A
- Protection - external barrier protecting underlying structures from physical trauma and invading organisms
- Sensory - sensory nerve endings in the surface of the skin to monitor the external environment
- Secretion - range of glands present in skin to produce secretions onto the surface
- Production - vitamin D is synthesised in the skin
- Storage - fat is stored in the hypodermic for energy and insulation
- Thermoregulation - mechanisms present to both increase and decrease heat loss
- Communication - scents and pheromones can be produced. Visual communication
2
Q
Skin
A
The skin is composed of layers:
- Epidermis - the superficial layer
- Dermis - the underlying layer
- Hypodermis - lies beneath the skin
3
Q
The epidermis
A
- Stratified squamous epithelium
- These cells are continuously renewed via mitosis
- New cells are produced in the deepest layers of the epidermis and pushed to the surface
- The dead cells are shed to the surface
Cell types: - Keratinocytes = produce keratin, the tough fibrous, waterproof protein that gives skin its resiliency and strength
- Melanocytes = produce melanin pigment
- Merkel cells = close to the nerve endings that receive the sensation of touch
- Langerhans cells = found in the stratum spinosum; involved in allergic and cell-mediated immune response in the skin
4
Q
Keratinocytes
A
- Make up 70-80% of the cells in the skin
- Structured and repackaged by 2 organelles in the cell, before it moves to the extracellular space
5
Q
Epidermal layers
A
1) Stratum germinativum/ Basal layer
2) Stratum spinosum - Spiny layer
3) Stratum granulosum - Granular middle layer
4) Stratum lucidum - Clear layer
5) Stratum corneum - Outermost layer
6
Q
Keratinisation
A
- Begins at granulosum
- Manufacture of skin cells starts at the base layer of the epidermis
- Keratinocytes are the primary cells that make up the epidermis
- As these cells move from deep to superficial layers they start to die (apoptosis)
- This releases both glycolipids (fat - hydrophobic) and keratin (protein)
- These form a waterproof barrier around the outside of the epidermis
7
Q
Dermis
A
- Composed of dense irregular connective tissue
- Contains hair follicles, nerve endings, glands, smooth muscle, blood vessels and lymphatics
Also includes: - Fibroblasts, adipocytes, and macrophages also present
2 layers: - Papillary layer
- Reticular layer
8
Q
Papillary layer (dermal)
A
- Underneath the epithelial layer of the epidermis
- Dermal papillae help cement the epidermis and the dermis together
- Blood vessels, pain, temperature, and touch receptors also present
- Blood vessels in this layer are important for thermoregulation
9
Q
Dermal layers - reticular
A
- Consists of dense irregular connective tissue
- in areas where a great deal of bending occurs, dermal folds or flexure lines are present
10
Q
Hypodermis
A
- Composed of areolar/adipose tissue, blood and lymphatic vessels, and nerves
- Contains special touch receptors - the Pacinian corpuscle and Meisner’s corpuscle
- Hypodermic layers permits skin to move freely over underlying bone and muscle without putting tension on the skin
11
Q
Special features of integument
A
- Pigmentation
- Paw pads
- Planum nasale
12
Q
Pigmentation
A
- Melanin is produced by…
- Pigmentation is the result of the presence or absence of melanin granules in the extensions of melanocytes
- The more granules present, the darker the pigmentation
- Keratocytes arrange melanin on the side of the cell with greatest amount of sun exposure
- Acts to protect keratocytes from exposure to damaging UV rays
13
Q
Paw pads
A
- Thick layers of fat and connective tissue with exocrine sweat glands
- Outer surface is the toughest and thickest skin in the body
- Stratum corneum is thicker than all other layers combined
14
Q
Planum nasale
A
- Top of the nose in cats, pigs, sheep and dogs
- Usually pigmented
- Mucus produced by glands within nose
- Innervated by trigeminal nerve
15
Q
Chelonians
A
These include he species: Tortoise, terrapins and turtles
