skin

Question 1

Skin as an organ

Answer 1

• made up of 4 different tissue
• made up of different types of cells ( keratinocytes,merkel cells, melanocytes, langherans cells )
• involved in thermoregulation, immune system, UV protection, sensory reception

Question 2

layers of the skin

Answer 2

Epidermis : Basale, spinosum, granulosum, lucidum, corneum( no organelles)
Dermis: papillary- loose connective, reticular-irregular connective
hypodermis: adipose layer under the skin

Question 3

Keratinisation

Answer 3

Basale: stem cells
Spinosum- preparative layer. cells shrink, desmosomes are spikes. lipid solid in extracellular spaces.
Granulosum- keratohyalin formed. incorporation of keratin, cells flatten
Corneum: keratin cells, cells lose organelles.

Question 4

hair, nails, sweat glands

Answer 4

HAIR involved in thermoregulation. 
Hair follicle= hair + sheath
sebaceous gland-releases sebum
pilomuscle-attached to root of muscle. If hair contracts then muscle is erected. 
penetrated node of blood vessel

NAIL : generates from nail base. corneum layer= nail plate
SWEAT GLANDS : also involved in thermoregulation. eccrine gland found in dermis. coiled and straight duct in dermis. spiral in epidermis

Question 5

blood supply and sensory reception

Answer 5

blood supply through capillaries in the dermis and the subcutaneous tissue.
sensory reception due to nerve ending in the epidermis. presence of sensory receptors (pacinian-pressure corpuscle, pain, thermo, meissner’s )

Question 6

describe how the skin carries out its functions

Answer 6

1-thermoregulation: eccrine sweat glands and hair follicles
2-immune system: langherans cells
3-UV protection: melonocytes
4-wear and tear: cells divide very quickly especially in corneum.
5-waterproof: keratinocytes- contain keratin which is very hard, releases lipid which makes it waterproof