Physiology Flashcards
What are Blaschko’s lines?
Developmental growth lines that follow the way that skin is drawn out
Which embryological layers do the epidermis and dermis originate from?
Dermis = mesoderm Epidermis = ectoderm
What are the 2 main layers of skin?
Epidermis Dermis
How many layers does the epidermis have and what are they from deep to superficial?
4 layers: Basal layer Prickle cell layer Granular layer Keratin layer
Describe the keratin layer of the epidermis?
layers of corneocytes and cornified envelope, the waterproof barrier for the skin
Describe the granular layer of the epidermis?
contains cells that burst and produce fillagrin (protein that binds to water so keeps water in skin and sticks everything together, people with eczema have less of this )
Describe the prickle cell layer of the epidermis?
daughter cells of basal cell layer contains desmosomes which makes it look prickley
Describe the basal cell layer of the epidermis?
Basal cell layer
Give the 4 types of cells found in the epidermis and what do they do/where are they found?
Keratinocytes - produce keratin, throughout epidermis Melanocytes - pigment producing dendritic cells, found in basal layer Merkel cells - mechanoreceptors (detect if something crawls over you), found in basal layer Langerhans cells - antigen presenting cells, found in prickle cell layer
Which type of cells contain Birbeck granules (look like tennis rackets)?
Langerhans cells
What are skin appendages?
anything that is on the skin e.g. hair, nails, sweat glands etc
What is the pilosebaceous unit?
hair follicle + sebaceous gland
What do sebaceous glands secrete?
Seramite
What are the 3 different stages of hair growth?
Anagen = growing phase Catagen = resting phase Telogen = falling out phase
What are the different parts of a hair follicle and draw it out?
Internal root sheath
Cortex
Medulla
Matrix
Papilla
What are the different parts of a nail and the nail bed? Draw it out
Nail matrix
Nail bed
Hyponchium
Lunula
Nail plate
What is onchylosis?
raising of the nail from the nailbed (usually do to psoriasis)
What is the function of the dermoepidermal junction?
Junction between the dermis and epidermis that sticks the two layers together and is semipermeable to allow things to pass between them
What happens if the dermoepidermal junction doesnt work properly?
Epidermis and dermis don’t stick together properly and get blistering disorders
What does the dermis contain?
Collagen and elastin
Muscles
Blood vessels (supplies the epidermis)
Lymphatics
Macrophages
What is angioma?
Overgrowth of blood vessels in the dermis that push through into the epidermis (there arent vessels in the epidermis)
Which nerve supply to the skin is responsible for touch?
Somatic sensory nerves - free nerve endings and special receptors (corpuscles)
Which special somatic sensory receptors detect vibration and pressure?
Pacinian corpuscles = pressure
Meissners corpuscles = vibration
Which nerve supply innervates blood vessels, glands and muscles in the dermis?
Autonomic
Explain the difference between sebaceous, appocrine and eccrine glands?
sebaceous: attached to hair follciles and secrete seramite to lubricate skin
appocrine: found under arms and genital areas, produce odour
eccrine: sweat glands that are mainly found on palms and soles, keeps body cool
Which vitamins are fat soluble?
Vitamin A and Vitamin K
Which vitamins are water soluble?
Vitamin B3 and Vitamin C
Follicular papules on arms and thighs are a sign of deficiency of which vitamin?
Vitamin A
Purpura and easy bruising is a sign of deficiency of which vitamin?
Vitamin K
What are the signs/symptoms of Pellagra and which vitamin deficiency causes it?
4 Ds: dermatitis, delerium, diarrhoea & death
due to vitamin B3 deficiency
Hyperkeratosis around hair follicles and poor wound healing are signs of deficiency of which vitamin?
Vitamin C
Topic steroids are lipophilic. True or false?
True
Where are langerhans cells formed?
Bone marrow
