SKIN. HAIR. SKIN GLANDS.
1. Skin is composed of 3 layers:
A) epidermis (stratified squamous keratinized epithelium)
B) dermis (connective tissue):
C) hypodermis (white adipose tissue in adults).
2.
Epidermis is composed of 4 cell types : keratinocytes (90% of amount) and 3 types of star-shaped cells:
A) melanocytes;
B) Merkel cells;
C) Langerhans cells
3.
Keratinocytes form
5 layers in epidermis:
A) Stratum basale. Function- is origin for regeneration;
B) Stratum spinosum;
C) Stratum granulosum;
D) Stratum lucidum;
E) Stratum corneum. Function- is protection.
Keratinicytes arise from surface ectoderm.
4.
Melanocytes have many
cytoplasmic processes. Cytoplasm contains granules named melanosoms. It arise from neural crest.
5.
Merkel cells have many
cytoplasmic processes and form synaptic junction with afferent nerve fibre. Function- perception of touch irritations.
It arise from neural crest.
6.
Langerhans cells have many
cytoplasmic processes. Cytoplasm contains pingpong paddles-shapped granules. It are macrophages. Functoin – is phagocytosis of bacteria.
It arise from monocytes.
7.
Dermis is composed of
2 layers:
A) papillary layer (loose iirregular connective tissue);
B) reticular layer (dense irregular connective tissue).
Dermis arises from dermatome of somite.
8. Hair is composed of elongated keratinicytes. On the cross section it has 3 layers:
A) medulla
B) cortex
C) cuticle
9.
Sweat glands morphologically are simple tubular exocrine glands. Type of releasing of sweat may
be merocrine or apocrine.
10.
Sebaceous glands morphologically are simple acinar glands. Type of sebum releasing is
holocrine.
Куратор темы – доцент В.В. Бондаренко.