TOB Flashcards
What do Haematoxylin and eosin stain?
H - acidic components e.g. nucleolus
E - Stains basic components e.g. proteins
What does periodic acidic schiff stain?
Carbs and glycoproteins magenta
What are the 3 methods of secretion with regards to glands?
merocrine, apocrine, holocrine
merocrine - exocytosis
Define resolution
Minimum distance at which 2 objects can be distinguished
What colour do gram negative and gram positive bacteria stain? Describe the process of gram staining
Gram negative - red
Gram positive - blue
1) crystal violet binds to outer wall of bacteria
2) Iodine added and forms complex with crystal
3) acetone extracts complex through gram -ve cell wall but not through gram positive
4) red dye added to staim gram -ve
What does acid fast stain for?
TB and leprosy bacteria
Give an example of a DNA enveloped and non eveloped virus, and an RNA enveloped and non enveloped virus.
DNA enveloped - Hep B
DNA non enveloped - HPV
RNA enveloped - HIV
RNA non enveloped - Hep A
What is cartilage composed of?
Mesenchymal cells, type 1 collagen, ground substance
What are the 3 types of cartilage and give an example of where each can be found
- Fibrocartilage - IV discs, pubic symphysis
- Hyaline - Resp passageways
- Elastic - ear
Describe the process of bone repair
Break –> haematoma –> cartilage callus –> primary bone –> secondary bone
- Bone breaks and inflammatory cells invade and form pre-callus containing blood clot
- Osteo callus of primary bone made which calcifies to secondary
- Bone pulled and presssured by tendons to match surrounding bone
What are the 4 layers of the skin?
Horny Gays Poke Butts
- Horny layer
- Granular layer
- Prickle cell layer
- Basal layer
Describe the process of keratinocyte differentation
- Keratinocyte misosi in basal layer
- Keratinocytes lose ability to divide in pricke cell layer
- Keratinocytes synthesise keratin
- Keratinocytes lose their PM and differentiate into corneocytes in horny layer.
What are the 2 types of sweat glands in the skin? Where is each found?
Eccrine (everywhere) and apocrine (arm pits and genitals)
What causes psoriasis?
Basal layer proliferates too much, results in thickening of prickle cell layer and horny layer. Manifests as excessive scaling
What is vitiligo and alopecia?
Autoimmune attack on melanocytes and hair follicles respectively
Explain the causes of:
- osteogenesis imperfecta
- osteoporosis
- rickets
- osteomalacia
- Genetic disease. Deficiency in collagen
- Weaker bones due to fall in sex hormones and aging
- Calcium deficiency in children. Bowed legs.
- Calcium deficiency in adults
What is achondroplasia and how is it caused?
Cause of Dwarfism
Defect is in epiphyseal growth plates. Thin and therefore dont grow much.
Explain how muscle contracts
- ATP binds to mysoin head and causes it to uncouple from actin
- ATP hydrolysed and head cocked.
- Pi released and myosin binds to actin and causes power stroke. ADP released.
How does skeletal muscle repair itself?
Satellite cells repair and can fuse with muscle cells to hypertrophy.
What is myasthenia gravis and what are the symptoms? How is it treated?
MG is autoimmune destruction of end plate ACh receptors and widening of synaptic cleft
Symptoms are drooping eye lids, double vision and fatigue of contracted muscles.
Treated with AChesterase inhibitors
What is duchenne’s muscular dystrophy? Symptoms and treatment?
Absence of dystrophin which anchors actin filaments to cell wall. Results in cell tearing itself apart on contraction and cell death.
Symptoms - pseudohypertrophy, gowers sign, contractures
Treatment - steroid therapy, ataluren (drug)
What is malignant hyperthermia? What is its pattern of inheritence? How is it treated?
Autosomal dominant
General anasthesia results in uncontrolled skeletal muscle oxidation, overwhelming resp system and leading to circulatory collapse
Treatment - Dantrolene (muscle relaxation)
