Physiology Flashcards
<p>What is the largest organ in the body? </p>
<p>The skin </p>
<p>How many skin diseases are there? </p>
<p>>2000</p>
<p>What are the layers of the skin from top to bottom? </p>
<p>Epidermis
Dermo-epidermal junction
Dermis
Subcutaneous </p>
<p>What is the subcutaneous composed of? </p>
<p>Predominantly fat</p>
<p>What is the epidermis mainly composed of? </p>
<p>Keratinocytes</p>
<p>What are the different layers of the epidermis from top to bottom? </p>
<p>Keratin layer
Granular layer
Prickle cell layer
Basal layer</p>
<p>Does the epidermis contain melanocytes? </p>
<p>Yes </p>
<p>Does the epidermis contain Langerhans cells? </p>
<p>Yes </p>
<p>Does the epidermis contain merkel cells? </p>
<p>Yes</p>
<p>Which parts of the body have very thick layers of keratin? </p>
<p>Soles of feet
| Palms of hands </p>
<p>Why is it beneficial to have thick keratin layer of hands and feet? </p>
<p>Protection
| Increases sensitivity </p>
<p>What controls the epidermal turnover? </p>
<p>Growth factors
Cell death
Hormones</p>
<p>What control is lost in diseases such as psoriasis? </p>
<p>Shedding of skin i.e. epidermal turnover, skin no longer releases keratin </p>
<p>How long does it take a keratinocyte to move from the basement membrane to the epidermis? </p>
<p>28 days </p>
<p>What is the basal layer of the epidermis composed of ? </p>
<p>Cuboidal cells
| Intermediate filaments</p>
<p>What cells make up the prickle layer of the epidermis? </p>
<p>Large polyhedral cells with many desmosomes </p>
<p>What causes a blister? (think of the wetness produced) </p>
<p>Fluid gets into the prickle cell layer of the epidermis, increasing the pressure. This causes the cells to lyses and the surface of the skin to split</p>
<p>What layer of the epidermis is missing in eczema? </p>
<p>Granular layer </p>
<p>What cells make up the granular layer of the epidermis and what is their main purpose? </p>
<p>2-3 layers of flatter cells
| Prevents water loss </p>
<p>What is the kertain layer of the epidermis composed of ? </p>
<p>Corneocytes (terminally differentiates keratinocytes) </p>
<p>What is the most important purpose of the keratin layer? </p>
<p>tight waterproof barrier, which is essential for survival </p>
<p>What 2 components mainly make up the keratin layer of the epidermis? </p>
<p>Keratin
| Filaggrin </p>
<p>What is the dermis composed of? </p>
<p>Connective tissue </p>
<p>Epidemiologically, what is the dermis composed of? </p>
<p>Mesoderm</p>
<p>What are melanocytes? </p>
<p>Pigment producing cells from the neural crest </p>
<p>What are Blaschko's lines? </p>
<p>Developmental growth patterns of the skin</p>
<p>Name the labelled structures</p>
Matsticatory mucosa in the mouth is kertatinised - why?
To protect from friction and pressure
Is the lining mucosa of the oral cavity keratinised?
No
What are langerhans cells and where are they found?
Langerhans cells are dendritic cells (antigen-presenting immune cells) of the skin and mucosa, and contain large organelles called Birbeck granules. They are present in all layers of the epidermis
What organelle within melanocytes actually produces melanin?
Melanosomes
What is brown or black pigment called?
Eumelanin
What is red or yellow pigment called?
Phaeomelanin
What cell transfers melanosomes from melanocytes to keratinocytes?
Dendritic cells
What it Vitiligo?
Auto-immune disease with loss of melanocytes
What is Albinism?
Lack of production of melanin
What is Nelson’s Syndrome?
Nelson’s syndrome is a rare disorder and occurs in patients who have had both adrenal glands removed due to Cushing’s disease. During the disorder the patient develops macroadenomas that secrete adrenocoritropin (ACTH)
What is malignant melanoma a cancer of?
Melanocytes
What layer in the epidermis are langerhans cells situated?
Prickle cell layer
Where do langerhans cells originate from?
Bone marrow