Week 3: Epidermis, Dermis, Hair and Hypodermis/Bones and Cartliage

Question 1

5 properties of the epidermal layers (Stratum __________)

Answer 1

1. Stratum Corneum - Filled with Keratin, thickened plasma membrane, glycolipids in extra cellular space - waterproof and tough
2. Stratum lucidum - clear layer, thick skin only
3. Stratum granulosum - Two types of granules: one helps form keratin, the other contains glycolipids which are spewed into the ES space
4. Stratum spinosum - desmosomes, dendritic cells and melanin +++
5. Stratum basale - (germinativum) - new keratinocyte proliferation, melanocytes.

(New epidermis every 25-45 days)

Question 1

What are desmosomes?

Answer 1

Desmosomes are specialized adhesive protein complexes that localize to intercellular junctions and are responsible for maintaining the mechanical integrity of tissues.

Question 2

What is Metastasis (Linked to cancer)

Answer 2

the development of secondary malignant growths at a distance from a primary site of cancer: an increased risk of metastasis. Mutated cells drifting in the blood stream and growing somewhere else.

Question 3

What is the dermis characteristics

Answer 3

• Made up from connective tissue
• Highly vascularised (many blood vessels)
• Cushions the body from stress and strain
• involved with temperature regulation
• protects underlying tissue
• origin of your “fingerprints” 0 dermal ridges

Also contains:

• Sweat glands
• Hair follicles and associated sebaceous (oil) glands
• nervous (sensory) tissues
• microscopic muscle tissue

Question 4

Areolar tissue characteristics

Answer 4

• supports and binds tissues
• holds body fluids
• defends against pathogens
• stores nutrients
• many cell types
• found within dermis

Question 5

irregular connective tissue characteristics

Answer 5

• Closely packed, thick bundles of collagen fibres
• provides resistance to tension
• fibres are arranged in multiple planes
• collagen = Strength
• found in dermis

Question 6

what are the 2 layers in the dermis

Answer 6

• Papillary (20%)

- Reticular (80%)

Question 7

What are the two type of sweat glands?

Answer 7

1. Eccrine
   - Palms of hands, sole or feet and forehead
   - secrete (true) sweat
2. Apocrine
   - exhillary (armpit) area and genitals
   - secretes sweat with fatty substance and proteins
   - secrete pheromones

Question 8

What are the two modified apocrine sweat glands

Answer 8

Ceruminous glands (ear wax)

Mammary glands (females secrete milk)

Question 9

Remember: sebaceous (oil) glands

Answer 9

functions to lubricates hair and slow water loss

mainly controlled by hormones such as testosterone.

Question 10

what melanin causes red hair, then brown, blonde and black

Answer 10

Red hair: Phaeomelanin

Rest: eumelanin

Question 11

What are the three coats of hair?

Answer 11

Lanugo (Lose it 1-2 months before birth

Vellus (fine pale body hair)

Terminal hair (Hair you can see)

Question 12

What are the 5 basic bone types?

Answer 12

Long - elongated shaft plus two expanded ends

Short - roughly cube shaped

Sesamoid - forms in tendons

Flat - Thin, flattened, usually slightly curved

Irregular - complicated shapes

Question 13

Characteristics of smooth and compact bone

Answer 13

Compact Bone: Dense outer layer, smooth and solid

Spongy Bone: Internal to compact bone, honeycome of trabeculae, contains red and yellow bone marrow

Question 14

What is the structure of the long bones?

Answer 14

Tubular diaphysis - surrounds medullary cavity

Medullary cavity. - Yellow marrow (fat)

2x epiphyses - surrounds spongy bone

Membranes - periosteum, endosteum

Question 15

What are the 4 cells of bone tissue

Answer 15

Osteogenic - Stem cell

Osteoblast - Bone growth

Osteocyte - monitors and maintains mineralised bone matrix

Osteoclast - bone reabsorbing (eating bone)

Question 16

What are the 3 types of cartliage in the body?

Answer 16

Hyaline

Elastic

fibrocartliages