Skin, Sense and Pain Flashcards

Question

Mechanoreceptors – touch

Answer 1

Itch / tickle sensations (tactile) detected by free nerve endings in skin surface to small unmyelinated fibres (slower response) Itch caused by chemicals cause a local inflammatory response Still unknown why you can’t tickle yourself!! Four types of touch receptors two categories Fast Adaption: Corpuscles of Touch / Meissner corpuscles Hair root plexuses – detect hair movement Slow Adaption Tactile (Merkel) discs –lips, genitalia, hands Ruffini corpuscles: sensitive to stretch

Answer 2

Pressure: Sensation sustained over larger area Tactile (Meissner’s) corpuscles: Detect fine touch and texture Vibration Lamellated (Pacinian) corpuscles: Detect heavy pressure and vibrations

Answer 3

Needed for survival; signals presence of tissue damaging conditions Nocireceptors (harm receptors); free nerve endings everywhere except the brain Complex and not fully understood; very subjective Two types Fast/acute pain: <0.1 second; medium size myelinated fibres Only felt in superficial tissues, very localised Slow/chronic pain: >1 second, increases in intensity over seconds/minutes; smaller unmyelinated fibres Occurs both in skin (may follow acute) and deeper tissues and organs, more diffuse Superficial somatic pain; skin Deep somatic pain; muscles, joints, tendons etc. Visceral pain; of deeper tissues/organs. May not feel localised stimuli of somatic pain Referred pain; visceral pain felt in/deep to skin overlying/remote from organ Phantom limb sensation: patient continues to experience pain after amputation

Answer 4

Inflammation, in which blood vessels dilate and become more permeable, causing tissues to become red and swollen, is the body's normal response to injury. Superficial cuts :epidermal healing- filled by reproducing epithelial cells. A deeper injury with broken blood vessels involves the formation of a blood clot More complex as multiple layers involved; results in scar tissue

Answer 5

Inflammatory phase: Blood clot forms to unite edges and protect deep tissues Inflammation to remove microbes, foreign debris, and dead tissue Migratory phase: Clot becomes scab, epithelial cells migrate deep to scab to bridge wound Fibroblasts start to develop early scar (granulation) tissue of collagen and glycoproteins Proliferation phase: Extensive growth of epithelial cells deep to scab Fibroblasts continue to produce random matric of collagen Blood vessels redevelop Maturation Phase: Scab comes off once epidermis of normal thickness Collagen fibre matrix becomes more organised, fibroblasts reduced

Answer 6

Changes start to become noticeable in late forties; mostly within dermis Wrinkles: Collagen reduces, becomes stiffer and more disorganised Elastic fibres lose elasticity and thickened (accelerated in smokers) Reduction in fibroblasts to produce new collagen/elastic fibres Decreased immunity/protection: Fewer Langerhans cells, less-efficient macrophages Sebaceous glands smaller; dry/broken skin Less sweat; heat stroke Loss of melanocytes; skin cancer and liver spots/greying hair Thinner skin: Loss of subcutaneous tissue and slower migration of epidermal cells Brittle and slower growing hair and nails

Answer 7

Commonest type of skin cancer Typical patient – 70-80, fair skinned Arises from the basal layer of the epidermis Locally aggressive but low metastatic potential. High rate of recurrance Imaging US Small lesions have a well defined heterogenous appearance. MRI Lesion will look hyperintense and will enhance if gadolinium is given

Answer 8

Common in the head and neck Most common head and neck cancer Arise from a mucosa or cutaneous origin Can be external or within the Nasopharynx Sinuses Mouth Larynx Treatment – depends on site, but generally surgery and radiotherapy / chemotherapy

Answer 9

Disease of advancing age. If it is within the mouth and throat – most common cause is smoking and HPV Use of imaging In diagnosis, staging and follow up Contrast CT is usually the first line imaging method. If the mass is in the neck, US and a US guided fine needle biopsy is used MRI is increasing being used depending on availability Imaging’s use in follow up is to assess for radio necrosis and recurrence Follow up is generally performed with CT, PET if available.

Answer 10

Also called a malignant melanoma Malignant neoplasm that arises from melanocytes in your epidermis. But can also grow in the eye Has an aggressive tendency to metastasise most commonly to skin, lymph nodes, lung, liver, bone and brain. Risk factors include – sunburn as a child or adult, fair skin, outdoor lifestyle, radiation exposure Survival rates depends on thickness of tumour - <1mm up to 96% survival, >4mm, around 40% Less than 5% of all skin cancers but is the leading cause of death in skin cancer stats

Answer 11

The most frequent site of involvement of metastatic disease is the lymphatic system – especially the lymph nodes in the area of the primary lesion The detection of lymph spread is the most important predictor of survival. Treatment depends on the extent of disease. Excision of the primary tumour is the first treatment. Lymphadenectomy can also be performed. Imaging is used to diagnose and assess progression and treatment outcomes US – assess lymph nodes CT – best imaging method for assessing lymph nodes. The nodes are assessed for size and density – should not he heterogenous PET-CT – most sensitive for assessing the chest MRI is the best imaging method for brain metasteses

Answer 12

This is tissue injury from direct tissue necrosis from freezing and indirect tissue injury from inflammatory changes Most common sites are the hands, feet, face and ears Imaging is mainly used to assess the bones and look for any secondary injuries Radiographs Can see tissue swelling and breakdown of the distal bones Nuclear medicine Can be useful to assess tissue viability – identify healthy and ischaemic tissue

Answer 13

Occurs after long term pressure of soft tissue under bony prominences They evolve over time and result from ischaemia and a local inflammatory reaction, bacteria colonizing the upper layers of skin eventually leading to skin erosion, and possibly muscles and bone Most commonly seen on the sacrum, scapula, occiput, greater trochanter Imaging CT is the best imaging method to evaluate as it shows The ulcer cavity, any loss of tissue, and abscesses or gas and any bone erosion

Answer 14

Itchy rash across body Complications Encephalitis Pneumonia If mother is not immune, damage to an unborn fetus

Answer 15

Highly contagious. Patients have a red, flat rash. Complications can include Pneumonia Encephalitis (inflammation of the brain)

Answer 16

Responsible for maintaining homeostasis Temperature regulation Protection of underlying tissues Slows water loss Houses sensory receptors Synthesizes certain biochemicals Excretes wastes Part of the process to make vitamin D

Skin, Sense and Pain Flashcards

(42 cards)