Microanatomy Flashcards
What are the key features of the skin
Sweat pore, sebaceous gland, sweat duct, hair follicle, sweat gland, pacinian corpuscle, arrector pili muscle, free nerve endings, Meissner’s corpuscle, hair shaft
What are two synonyms for the hypodermis
Subcutis and superficial fascia
What is the function of Meissner’s corpuscle
Touch mechanoreceptor
What is the function of pacinian corpuscle
Pressure/ vibration mechanoreceptor
What is the function of the arrector pilli
Smooth muscle of arrector pili contracts to pull the hair shaft upright to trap air in and aid insulation
What are the two layers of the dermal-epidermal junction
Top layer= stratum basale
Bottom layer= paillary dermis
What fibres are located in the papillary dermis
Collagen
What junctional complex present in the stratum spinosum is affected in pemphigus
Desmosomes
What effect does sunlight have on the skin
Causes skin to age prematurely- damage to skin layers
Describe the histological changes in the skin that may account for the differences seen in the skin of the infant and older person
Epidermis thins; loss of matrix and water from the dermis results in wrinkles; loss of elastic and other fibres from dermis (elastosis) results in ‘leathery’ look to skin; hypodermis thins; melanocytes decrease but remaining melanocytes increase in size- ‘age/liver spots’; sebaceous gland produce less sebum- dried appearance of skin; sweat glands produce less sweat
Which cells, layers or structures are involved in vitamin D production
Stratum basale/ spinosum
Which cells, layers or structures are involved in waterproofing
Stratum corneum
Which cells, layers or structures are involved in sensory perception
Pacinian corpuscle
Which cells, layers or structures are involved in protection from UV radiation
Melanocyte
Which cells, layers or structures are involved in temperature regulation
Sweat duct
What is the function of a Merkel cell
Involved in fine sensory perception, also neuroendocrine
Why are melanocytes dendritic cells
They are branched and the dendrites transfer the melanin to adjacent epidermal cells
Name a disease in which the concentration of salt NaCl is increased in sweat
Cystic fibrosis
Why is cystic fibrosis more common in populations in higher latitudes than near the equator
Don’t know advantages of cystic fibrosis trait. Gene may lend resistance to Cholera and other sources of bowel inflammation, diarrhea and dehydration
What the key differences between thick and thin skin
Thickness of the stratum corneum and extent of papillary ridges, absence of hair follicles in thick skin, stratum lucidum present in thick skin
What are the main histological changes seen in the epidermis in psoriasis
Hyperkeratosis (abnormal maturation of the skin and thickening of the stratum corneum); loss of stratum granulosum or granular layer; epidermal hyperplasia with thickening of the stratum basale and spinosum and elongation of papillary ridges (hyperproliferation); vascular dilation (vessels are abnormal as well); generalised inflammation with lymphocytes in the dermis and epidermis
What are the cells, fibres and ground substance found in connective tissue proper
Extracellular matrix; collagen fibres; ground substance; mesenchymal cell; elastic fibres; fibroblast; reticular fibres; blood vessel; macrophage; adipocyte
Where are elastic fibres found
In elastic cartilage
Where are chondrocytes found
In fibrocartilage
What are the 3 types of cartilage
Elastic cartilage, fibrocartilage, hyaline cartilage
Name two sites in the body where you would find elastic cartilage
Larynx and auricle of external ear
Name two sites in the body where you would find fibrocartilage
Intervertebral disc (annulus fibrosus) and pubic symphysis
Name two sites in the body where you would find hyaline cartilage
Articular ends of long bones and trachea
In long bone, what is located between the endosteum (inside) and periosteum (outside)
Compact bone
What cartilage is located on the end of the proximal epiphysis in compact done
Articular cartilage
What is located in the metaphysis of long bone
Red bone marrow and spongy bone
What is the inside of long bone called
Medullary cavity
What is a BMU (basic multicellular unit)
Local groups of osteoclasts and oesteoblasts
What is the function of the BMU
Responsible for bone remodelling
What is meant by skeletally immature
Open growth plates
What are osteoclasts
Large multinucleate bone cells which absorb bone tissue during growth and healing
What are osteoblasts
Cells which secrete the substance of bone
What is an osteocyte
A bone cell formed when an osteoblast becomes embedded in the material it has secreted
Describe the stages of an injury to the skin with the loss of tissue which heals by second intention
Development of granulation tissue, “organisation”, scar formation, wound contraction
