1-G Skin Histology Flashcards
Define the two types of skina and where they are found.
Thick skin is found on palms and soles of feet, areas that need greatest protection from abrasion; thin skin is found everywhere else on the body
What type of connective tissue is the papillary dermis
loose connective tissue
What type of connective tissue is reticular layer of the dermis
type I collagen densse irregular connective tissue; also includes vasculature, innervation, hair follicles and glands.
Reticular layer of dermis is organized in by ____ ____ (important in scarring)
Langer’s Lines
What types of tissue are found in hypodermis?
adipose and loose connective tissue
What are the 5 layers of the epidermis
basale, spinosum, granulosum, lucidum, coneum
Name important characteristics of the 5 layers.
Basale (basement membrane, spot desmosomes and hemidesmosomes); Spinosum (many spot desmosomes); Granulosusm (granules of keratohyalin and dense homogenous deposit granules of for water barrier); Lucidum (dead cells); Corneum (being sloughed off)
What is the function of Langerhans cells
they are the immune cells of the skin (easily damaged by UV)
What is the function fo Merkel cells
located in the basal layers of epidermis and contain neurosecretory granules and work with sensory neruons
What embryonic tissue are melanocytes derived from
neural crest
Describe the structure of hair follicles
interaction between dermis and epidermis cause the epidermis to invaginate into the dermis, at the base of mature follicle there is atuft of vascular loose connectibe tissue called the dermal papilla that stimulates the production of hair (hair made of karatinocytes and melanocytes); can go through cycles of growth and dormancy
What serves as the duct for sebaceous glands
hair follicle
Integrate the functional relationship between hair follicles, sebaceous glands and arrector pili muscles
Arrector pilli muscles can cause secretion of sebaceous glands into the hair follicles that are used as a duct
Explain how sebaceous gland produce and secrete sebum
cells fill with oily product until their death and then are excreted by holocrine secretion
Name the two types of sweat glands
eccrine (most common for thermoregulation and intiated by sympathetic ) Apocrine (secret into hair follicles in the axilla, nipple and genital area producing a viscous sweat)
What is the motor innervation of the skin
smooth muscle of the arrector pili muscle and blood vessels is innervated by sympathetic nervous system which is necessary for thermoregulation
Describe the types of unencapsulated
free nerve endings detect pain and temperature; Merkel endings are touch receptors that contact Merkel cells
Describe the types of the encapsulated receptors
mesissner’s corpuscles (light touch receptors nestled in dermal papilla); pacinian corpuscles are vibration receptors found in the dermis or hypodermis
Contrast the embryonic origins of the epidermis and dermis
dermis (mesoderm) epidermis (ectoderm)
What is hypodermis also know as
subcutaneous tissue or superficial fascia
What is another name for investing fascia
describes the outermost layer of fascia surrounding skeletal muscle- epimysium
What are the two major types of skin cancer?
basal cell carcinoma (stem cells grow out of control, clear border) and melanoma (uncontrolled growth of melanocytes due to over exposure to sun, can invade deep tissues and metastisize)
How does psoriasis affect cell proliferation within the epidermis
immune system alters the growth rate of epidermis leading to 4 day transit and redness due to growing tissue
Describe two conditions that lead to altered malanocyte function
albinism (decreased ability to synthesize melanin- lack of tyrosinase) and addison’s disease (over expression of MSH, increasing skin pigmentation.
