Integumentary System

Question 1

What are the components of the integumentary system?

Answer 1

Cutaneous membrane, accessory structures

Question 2

What are the functions of the integumentary system?

Answer 2

Protection (from pathogens), excretion, thermoregulation, melanin and keratin production, vit D synthesis, sensation

Question 3

What does the cutaneous membrane consist of?

Answer 3

Epidermis - epithelial tissue
Dermis - Papillary layer and reticular
Hypodermis - loose connective tissues

Question 4

What are the accessory structures?

Answer 4

Hair shaft, corpuscles, sweat glands and sebaceous gland

Question 5

What is the structure of the epidermis?

Answer 5

Surface
Stratum Corneum
Stratum Lucidum
Stratum Granulosum
Stratum Spinosum
Stratum basale
Basement membrane

Question 6

How is the epidermis regenerated?

Answer 6

Basal keratinocytes divide on the basale push the daughter cells up they then change shape becoming less fluid they shrink and dehydrate in the spinosum. Keratin is then produced and cells start apoptosis in the granulosum. They are then flattened and clear in the lucidum. In the corneum they are dead and have no organelles and are then shed from the surface

Question 7

What is the function of replacing the epidermis constantly?

Answer 7

Aids protection and reduces damage

Question 8

What regulates the replacing of the epidermis?

Answer 8

Accelerated by epidermal growth factor - stimulates cell division, keratin production and glandular secretion

Question 9

What are fingerprints?

Answer 9

Epidermal ridges

Question 10

Compare and contrast thick skin and thin skin

Answer 10

Location thick is fingertips, palms and soles whereas thin is everywhere else
Thick has a thicker strata lucidum, spinosum and corneum thin doesnt have a lucidum
Thick has epidermal ridges
Thin has hair follicles
Thick has more sweat glands and sensory receptors

Question 11

What are melanocytes?

Answer 11

They produce melanin which is a brown pigment which is incorporated into the keratinocyte and distributed
It protects from UV and is stimulated by the sun

Question 12

What other things can determine skin colour?

Answer 12

Carotene - a yellowish pigment
Blood - a pink or blue coloration

Question 13

Outline the structure of the dermis

Answer 13

Mainly collagen and elastin fibres (connective)
Papillary layer - areolar tissue
Reticular layer - fibrous network
Blood vessels - papillary plexus - blood flow to the skin - cutaneous plexus
Sensory receptors

Question 14

Outline the structure of the hypodermis

Answer 14

Subcutaneous layer of the superficial fasciae
Loose connective tissue - areolar and adipose
Flexible layer - allows the skin to move relative to the underlying structures

Question 15

Describe the structure and function of the hair follicle

Answer 15

Exposed hair shaft
Sebaceous gland - oily sebum
Arrector pili muscle - contracts when cold causing goosebumps and erecting hairs which traps more air
Root hair plexus for sensation
Function - insulation and protection and sensation

Question 16

What is the structure of hair?

Answer 16

Medulla - core - flexible soft keratin
Cortex - thick layers of hard keratin- stiffness
Cuticle - thin but tough, contains hard keratin

Question 17

What is the structure of the follicle?

Answer 17

Internal root sheath - surrounds root and deeper portion of the shaft
External root sheath
Glassy membrane - thickened clear layer
Connective tissue sheath

Question 18

How does hair grow?

Answer 18

Daughter cells divide in the matrix these are pushed towards the surface (0.33mm/day) and are increasingly keratinised. The follicle then becomes inactive and connections between the matrix and root break down and the old hair is shed

Question 19

What are the sebaceous glands?

Answer 19

Secrete sebum
Stratified and cuboidal epithelium
Onto hair and skin - for protection and waterproofing

Question 20

Outline the structure and function of the nails

Answer 20

Protection - limit distortion
Nail body - keratinised epithelial cells
Lunula
Eponychium- cuticle - stratum corneum
Nail production - cells pushed out

Question 21

What are the 2 types of sweat gland?

Answer 21

Apocrine and merocrine

Question 22

What is the difference between the 2 types of sweat gland?

Answer 22

Apocrine - secrete thick odorous fluid into hair follicles in the arm pit and pubic region whereas merocrine is less deep in the dermis and discharge watery fluid onto the skin for cooling and protection

Question 23

Outline skin cancer

Answer 23

Uncontrolled cell division
78% are basal cell carcinomas - small lump on the skin
2% are malignant melanoma - melanocytes divide uncontrollable - metastasise

Question 24

Is the risk of skin cancer increased?

Answer 24

Sun burn destroying the DNA

Question 25

Outline burns

Answer 25

1st degree burn - affects the epidermis - reddening - more blood and inflammation - heal rapidly
2nd degree burn - some dermis damage - blisters, scar tissue
3rd degree burns - burn through to the hypodermis - sensory nerves destroyed - may disrupt fluid and electrolyte balance, thermoregulation, protection from infection

Question 26

How are injuries repaired?

Answer 26

1. Bleeding into the wound - mast cells secrete inflammatory markers - attract cells for the immune response
2. Clot scab - with fibrin network, Cells of stratum basale migrate around the edges of the clot, phagocytes arrive, fibroblasts produce granulation tissue replacing connective tissue
3. Mesh - epidermal cells under the scab, phagocyte activity reduced, fibrin clot breaks
   4.Epidermis is complete - shallow depression- fibroblast activity continues - scar tissue - contains more collagen and less accessory structures

Question 27

Outline skin ageing

Answer 27

Intrinsic - inside the body e.g. reactivity of cells, growth factors, hormones, immune sensitivity causes dermal thinning, wrinkling, white hair, increased infection risk, slower healing

Extrinsic - external factors e.g. sunshine exposure, smoking causes increased wrinkling and skin cancer risk