TOB

Question 1

What do Haematoxylin and eosin stain?

Answer 1

H - acidic components e.g. nucleolus

E - Stains basic components e.g. proteins

Question 2

What does periodic acidic schiff stain?

Answer 2

Carbs and glycoproteins magenta

Question 3

What are the 3 methods of secretion with regards to glands?

Answer 3

merocrine, apocrine, holocrine

merocrine - exocytosis

Question 4

Define resolution

Answer 4

Minimum distance at which 2 objects can be distinguished

Question 5

What colour do gram negative and gram positive bacteria stain? Describe the process of gram staining

Answer 5

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

Question 6

What does acid fast stain for?

Answer 6

TB and leprosy bacteria

Question 7

Give an example of a DNA enveloped and non eveloped virus, and an RNA enveloped and non enveloped virus.

Answer 7

DNA enveloped - Hep B

DNA non enveloped - HPV

RNA enveloped - HIV

RNA non enveloped - Hep A

Question 8

What is cartilage composed of?

Answer 8

Mesenchymal cells, type 1 collagen, ground substance

Question 9

What are the 3 types of cartilage and give an example of where each can be found

Answer 9

1. Fibrocartilage - IV discs, pubic symphysis
2. Hyaline - Resp passageways
3. Elastic - ear

Question 10

Describe the process of bone repair

Answer 10

Break –> haematoma –> cartilage callus –> primary bone –> secondary bone

1. Bone breaks and inflammatory cells invade and form pre-callus containing blood clot
2. Osteo callus of primary bone made which calcifies to secondary
3. Bone pulled and presssured by tendons to match surrounding bone

Question 11

What are the 4 layers of the skin?

Answer 11

Horny Gays Poke Butts

1. Horny layer
2. Granular layer
3. Prickle cell layer
4. Basal layer

Question 12

Describe the process of keratinocyte differentation

Answer 12

1. Keratinocyte misosi in basal layer
2. Keratinocytes lose ability to divide in pricke cell layer
3. Keratinocytes synthesise keratin
4. Keratinocytes lose their PM and differentiate into corneocytes in horny layer.

Question 13

What are the 2 types of sweat glands in the skin? Where is each found?

Answer 13

Eccrine (everywhere) and apocrine (arm pits and genitals)

Question 14

What causes psoriasis?

Answer 14

Basal layer proliferates too much, results in thickening of prickle cell layer and horny layer. Manifests as excessive scaling

Question 15

What is vitiligo and alopecia?

Answer 15

Autoimmune attack on melanocytes and hair follicles respectively

Question 16

Explain the causes of:

1. osteogenesis imperfecta
2. osteoporosis
3. rickets
4. osteomalacia

Answer 16

1. Genetic disease. Deficiency in collagen
2. Weaker bones due to fall in sex hormones and aging
3. Calcium deficiency in children. Bowed legs.
4. Calcium deficiency in adults

Question 17

What is achondroplasia and how is it caused?

Answer 17

Cause of Dwarfism

Defect is in epiphyseal growth plates. Thin and therefore dont grow much.

Question 18

Explain how muscle contracts

Answer 18

1. ATP binds to mysoin head and causes it to uncouple from actin
2. ATP hydrolysed and head cocked.
3. Pi released and myosin binds to actin and causes power stroke. ADP released.

Question 19

How does skeletal muscle repair itself?

Answer 19

Satellite cells repair and can fuse with muscle cells to hypertrophy.

Question 20

What is myasthenia gravis and what are the symptoms? How is it treated?

Answer 20

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

Question 21

What is duchenne’s muscular dystrophy? Symptoms and treatment?

Answer 21

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)

Question 22

What is malignant hyperthermia? What is its pattern of inheritence? How is it treated?

Answer 22

Autosomal dominant

General anasthesia results in uncontrolled skeletal muscle oxidation, overwhelming resp system and leading to circulatory collapse

Treatment - Dantrolene (muscle relaxation)