Integumentary System Flashcards
What are the 5 functions of skin?
Protects: physical, chemical, & immune
Regulates: heat & fluid balance sweating/evaporation
Senses: touch, heat, and pain
Excretion (sweat) and absorption (some medications)
Storage (fat) & synthesis (Vitamin D)
What type of cells is the epidermis made up of?
stratified squamous epithelial cells
Describe the 4 or 5 layers of the epidermis.
Stratum corneum – more than 25 layers of dead squamous cells
(Stratum lucidum – 3-5 layers of translucent dead cells, only found in thick skin)
Stratum granulosum – 2-5 layers of flat diamond shaped cells
Stratum spinosum – 8-10 layers of many sided cells
Stratum basale – single layer cuboidal, basement membrane attaches to the dermis
Keratinocytes, melanocytes, merkel cells, and langerhan’s cells are all found in the epidermis, Describe them, e.g. function, where they are found.
Keratinocytes make up around 90% of epidermis. They are epithelial cells which produce keratin. This makes the skin durable and waterproof, protecting it. They are produced in the stratum corneum, nails & hair.
Melanocytes make up around 8% of epidermis, and produce melanin
Merkel Cells are receptors in the nervous system called mechanoreceptors, and are associated with nerve endings
Langerhans’ Cells are immune cells that capture & process microbial antigens
What is keratinisation?
Renewal of the epidermis is called Keratinisation. The cells in the stratum basale divide, and change shape and composition as they move from deep to superficial. As they do so they gain keratin and die. This can go wrong in diseases.
What is the difference between thick and thin skin?
Whether the skin is thick or thin is determined by the epidermis, and has no reflection on the actual depth of the skin.
Thick skin has all 5 epidermis strata, and the stratum corneum has many layers. Thick skin is found in areas of pressure or friction.
Thin skin has only 4 epidermis strata, and has no stratum lucidum. It is more flexible than thick skin, and each strata has less layers than thick. Thin skin covers most of the body. Hairs are only found on thin skin.
What is the dermis?
The dermis is strong, flexible, connective tissue rich in collagen and elastic. It contains: fibroblasts, macrophages, a few adipocytes, nerve endings, Blood vessels, glands, smooth muscle, and lymphatics.
What 3 things determine skin colour?
Pigments, Blood circulation, and Thickness of stratum corneum.
Describe the 3 skin pigments (melanin, carotene, and haemoglobin)
Melanin is the most important factor in skin/hair/eye colour
Carotene is from carrots and yellow veg. It is lipid soluble (dissolves in fat) and accumulates in the stratum corneum and in adipocytes of the dermis
Hemoglobin is the responsible for the ‘pink’ coloration of skin, and is found in blood in the dermis
Melanin is produced by _______. There is lots of melanin in ______ & ______ and less in _____ & ______. Melanin production determined by _________, _______ & exposure to _______.
Melanin is produced by MELANOCYTES There is lots of melanin in MOLES & NIPPLES and less in LIPS & PALMS. Melanin production determined by GENETICS, HORMONES, & exposure to LIGHT.
Describe these 4 clinical problems with skin colour: Cyanosed Jaundiced Erythema Pallor
If a patient is cyanotic, they are a bluish colour due to too much deoxygenated blood.
If someone has jaundice they have yellow colouration due to high levels of bilirubin in the blood
.
Erythema is a redness of the skin.
Pallor is pale or white skin due to a poor blood supply.
Sebaceous glands are located in the dermis on the entire body except palms and soles. What is their function?
They produce sebum by holocrine secretion, and then the cell ruptures & dies. Their function is to oil and lubricate which prevents skin drying out & makes it water-tight.
Where are sweat glands found? What is their function?
Sweat glands are found on the entire skin surface except nipples & part of external genitalia. They produce sweat to cool skin/body and are activated by heat, stress & exercise.
The skin is filled with ______ receptors, and each type responds to specific stimuli such as ______ or ______ or _____ or ______, etc. Each type differs in ______ & ________.
They ‘sense’ anything that comes into contact with them and send signal to brain. _______ _______ in the skin control_______ ________ & adjust ______ ________. They sense pain, temperature & touch, etc.
The skin is filled with SENSORY receptors, and each type responds to specific stimuli such as LIGHT or TOUCH or HEAT or PAIN, etc. Each type differs in STRUCTURE & PREVALENCE.
They ‘sense’ anything that comes into contact with them and send signal to brain. NERVE FIBRES in the skin control BLOOD FLOW & adjust GLAND SECRETIONS. They sense pain, temperature & touch, etc.
Acne is the most common skin disease in humans. What is it?
It is a bacterial infection, where the sloughing off cells block hair follicles, resulting in a pimple. It can be affected by hormones, sebum, & bacteria. It attracts neutrophils, which are “pus pockets”. Oil-based cosmetics worsen disease but diet has no effect.
What is the ABCDE of melanoma recognition?
A = Asymmetry B = Border irregularity C = Color not uniform D = Diameter > 6 mm E = evolving over time
Describe the 3 types of skin cancer (basal cell, squamous cell, melanoma)
Basal cell is the commonest, and affects cells of the stratum basale. It is typically on face, and is local spread
Squamous cell affects the stratum spinosum. It often bleeds and is cured by removal
Melanoma is the least common but most aggressive type of skin cancer, and arises from melanocytes
Odema is an excessive accumulation of ______ _______, causing the tissues to swell & expand. The lymphatic system returns ________ _______ to blood to re-circulate. Accumulation is determined by balance of secretion & removal of lymph fluid. In Pitting oedema, an indentation _______ while in non-pitting oedema an indentation _________.
Odema is an excessive accumulation of LYMPH FLUID causing the tissues to swell & expand. The lymphatic system returns INTERSTITIAL FLUID to blood to re-circulate. Accumulation is determined by balance of secretion & removal of lymph fluid. In Pitting oedema, an indentation PERSISTS while in non-pitting oedema an indentation DISAPPEARS.
Intradermal injections are into the skin. What are they used for? How are they given?
They are used for allergy and TB skin testing.
The needle should be inserted at a shallow angle to the inner surface of the forearm, back or upper chest. Only very small volumes should be injected this way.
To do it, stretch the skin and insert the needle to roughly 2-3 mm with the bevel up at a shallow angle – the needle should be visible under skin.
Subcut injections are into the subcutaneous tissue. What are they used for? How are they given?
This is a common mode of administering insulin and heparin.
A steeper angle should be used, inserting the needle into the outer surface of the upper arm, top of thighs, abdomen or back. Only small volumes
should be injected this way, and onset is within a half hour.
To do it, pinch up a fold of the skin and hold the needle like a dart and pierce the skin at a 45-90° angle.
IM injections are into a muscle or muscle group. What are they used for? How are they given?
Times an IM injection would be used include antibiotics, analgesics, and adrenalin.
The needle should be inserted at a steep angle into the deltoid or gluteal region (ventral or posterior approach). Larger volumes can be used and onset is variable.
To do it, stretch the skin and hold the needle like a “dart” and insert quickly at a 90° angle. Then, aspirate to check for blood before administering slowly and steadily.
Name 3 locations IM injections can be given.
IM deltoid injections are given high on the shoulder
IM lateral vestus injections are given laterally in the middle third of the thigh. It is the least dangerous sight as it is far away from the nerve and blood supply.
IM ventral gluteal injections are given in the triangle made by the index and middle fingers into the gluteus medius. Avoid the “danger zone” where the sciatic nerve is.
IV injections are given into a superficial vein, typically into the medial cubital vein. What are they used for?
It can be used for fluid and ion substitution, or taking a blood sample for example. Larger volumes can be injected and onset is immediate.
The danger zone is the brachial artery and median nerve.
