Integumentary System

Question 1

What are the components of the integumentary w

Answer 1

• cutaneous membrane, the skin: epidermis, dermis, hypodermis
• accessory structures, hair nails, glands, muscles, ducts follicles, nerve fibres

Question 2

Functions of system

Answer 2

Protection, excretion, maintenance of temperature, melanin production (protects from uv), keratin production (strength), synthesis of vitamin d for calcium absorption, sensation

Question 3

Epidermis

Answer 3

Top layer of skin
- stratified squamous epithelial cells
- basement membrane connected to dermis
Has papillae for surface area= muscle attach
- top layer dehydrated

Question 4

Epidermis renewal

Answer 4

Epidermal growth factor
- stimulates cell division, keratin production and glandular secretion

1.basal keratinocytes divide
2. Keratinocytes shrink and become dehydrated
3. Flattened clear cells
4. Dead and flat keratinocytes lacking organelles
5. Cells shed

5= outside

Question 5

Thick skin

Answer 5

On palms ext
5mm

• thicker epidermal strata with lucidum, spinosum and corneum
• deeper epidermal ridges
• no hair follicles
• more sweat glands and receptors

Question 6

Outline the dermis

Answer 6

Supports the dermis, collagen and elastic fibres

Divided into 2 layers
- papillary layer: areolar tissue
- reticular layer: fibrous network

Contains blood vessels and cutanous plexus under the papillary layer

Sensory receptors

Question 7

Outline the hypodermis

Answer 7

Layer underneath integument

• loose connective tissue, areolar and adipose
• connective tissue fibres interwoven with reticular layer of dermis

Question 8

Outline the fascia

Answer 8

The connective tissue network of a body (under the skin)

1. Superficial fascia - between skin and underlying organs, areolar and adipose tissue - the same as the hypodermis
2. Deep fascia- strong fibrous framework, dense connective tissue bound to joint capsules, tendons and ligaments
3. Subserous fascia - between serous membrane and deep fascia, areolar tissue

Question 9

Outline hair growth

Answer 9

• growth cycle up to 5 years
• basal cells in hair matrix divide
• daughter cells pushed up 3mm per day
• increasingly keratinised
• hair papillae contain blood vessels needed
• at end of cycle follicle becomes inactive
• connections between matrix and root break down
• new cycle, old shed

Question 10

Outline hair and follicle structure

Answer 10

Hair structure
- medulla, core, contains flexible keratin
- cortex, thick hard keratin layer for stiffness
- Cuticle, thin but tough, keratin

Follicle (inside to outside)
- internal root sheath: surround the root and inner shaft
- external root sheath
- glassy membrane, thicker and clear, wrapped in dense connective tissue
- connective tissue sheath

Question 11

Sebaceous glands and follicle

Answer 11

• secrets sebum onto shaft
• Waterproof
• reduce pathogens

Question 12

Outline nails and their structure

Answer 12

• protect fingers and toes
• keratinised epithelial cells
• eponychium = cuticle
• proximal nail fold
• Luluna
• nail body, keratinised epithelial cells
• free edge

Question 13

Outline sweat glands

Answer 13

Apocrine
- develop during puberty, pubic and armpits, thick odorous fluid onto hair glands

Merocrine
- watery substance directly into skin
- cooling
- excretion, protection and antibodies

Question 14

Repair of injury to the dermis

Answer 14

1. Bleeding within, mast cells = inflammatory response to wash away pathogens
2. In hours after blood clots, cells of stratum basale divide rapidly due to growth factor, debris removed
3. Mesh formed by fibroblasts scab by epidermis, fibrin clot breaks down
4. Epidermis now complete, shallow depression, fibroblast activity continues, maybe scar and no hair with more connective tissue

Question 15

Ageing

Answer 15

Intrinsic
- reduced cell activity, growth factors and hormones
- immune sensitivity
= dermal thinning, wrinkling, hair colour, notes infection and less healing

Extrinsic
- sunshine exposure
- smoking
= wrinkling and skin cancer risk