Lab Test #2 Study Guide (Skin Layers + Ribs + Joints)

Skin Layers + Ribs + Joints

Stratum Basale

Deepest (bottom)

- Cell division (new keratinocytes) - Contains melanocytes (UV protection) - Contains Merkel cells (touch)

Stratum Spinosum

Above basale

- Strength & flexibility via desmosomes - Starts keratin production - Contains Langerhans cells (immune)

Stratum Granulosum

Middle layer

- Waterproofing (via lipid granules) - Cells begin to flatten & die - Produces keratohyalin

Stratum Lucidum

Only in thick skin

- Extra protection - Flat, dead keratinocytes - Adds toughness to palms/soles

Stratum Corneum

- Dead, keratin-filled cells
- Protects against abrasion, pathogens, water loss
- Sheds/renews constantly

Thin Skin

covers most of body, has hair follicles, sebaceous glands, thin stratum corneum, no stratum lucidum.

Thick Skin

palms/soles, no hair, no sebaceous glands, thick stratum corneum, has stratum lucidum.

What tissue makes up the epidermis?

Stratified squamous epithelial tissue (keratinized)

What tissue makes up the dermis?

Dense irregular connective tissue

What makes the dermis?

Connective tissue (collagen and elastic fibers)

What are the layers of the dermis?

• Papillary layer (superficial, areolar CT, dermal papillae)

• Reticular layer (deep, dense irregular CT)

Vertebral sections:

• Cervical: 7

• Thoracic: 12

• Lumbar: 5

• Sacrum: 5 fused

• Coccyx: 4 fused

True Ribs

1-7

Flase Ribs

8-12

Fibrous

Bones connected by dense fibrous connective tissue - immovable

- Suture - Syndesmosis (long fibers) - Gomphosis (periodontal ligament)

Cartilaginous

Bones connected by cartilage - slightly moveable

- Synchondrosis (hyaline cartilage) - Symphysis (fibrocartilage)

Synovial

Covered in articular cartilage - freely movable

- Plane joint - Hinge joint - Pivot joint - Condylar joint - Saddle joint - Ball and socket joint