ToB

Question 1

What causes Marphans Syndrome? How does it present?

Answer 1

Its a deffect in the chromosome that codes for fibrillin which effects elastic fibers
Large elastic arteries rupture due to bulging under pressure

Question 2

What causes Ethlers-Danlos Disease? How does it present?

Answer 2

Deficiency in type III Collagen

Causes ruptures in tissues with high reticulin content

Question 3

What causes Psoriasis? How does it present?

Answer 3

Disorder of epidermal growth + differentiation
Causes extreme proliferation of basal layer, leads to thickening of prickle cell layer + production of excessive stratum corneum

Question 4

What is Alopecia Areata?

Answer 4

Autoimmune attack of hair follicles

Question 5

What is Vitiligo?

Answer 5

Autoimmune attack against Melanocytes, usually in symmetrical areas of skin

Question 6

What are the 3 types of cartilage?

Answer 6

Hyaline - Nose, Trachea, Articulating bone surfaces
Elastic - Epiglotis, External ear
Fibrocartilage - Intravertibral disks

Question 7

What is the structure of compact bone? How do different parts of the bone communicate?

Answer 7

Concentric Lamellae with central neurovascular cannal, these communicate via Volkmanns cannals

Question 8

What stimulates + Inhibits Osteoclasts?

Answer 8

Stimulated by PTH

Inhibited by Calcitoxin

Question 9

What causes Osteogenesis Imperfecta? What does it lead to?

Answer 9

Caused by a mutation to the type I Collagen gene

Leads to abnormal collagen synthesis by osteoblasts + fibroblasts, Leads to bone fragility

Question 10

Why is Vitamin D needed? What does a deficiency in Vitamin D lead to?

Answer 10

Needed in the absorbtion of Calcium + Phosphate in the small intestine
Deficiency leads to poorly mineralised + pliable matrix, causes effected bones to bend

Question 11

What happens in Rickets?

Answer 11

Bones fail to calcify normally. Bones grow slowly + become deformed, growth plates are distorted by body weight + muscle activity

Question 12

What happens in Osteomalacia and what causes it?

Answer 12

Bones soften due to calcium deficiency

Question 13

What happens to the bones in Osteoporosis?

Answer 13

Bone density is reduced as there is more activity of Osteoclasts than Osteoblasts, Medullary cannals become enlarged + gaps appear in lamellae

Question 14

What are the two different causes of Osteoporosis?

Answer 14

Type I - Occurs in post menopausal women, reduced oestrogen leads to increased number of osteoclasts
Type II - Occurs in both sexes due to reduced Osteoblast function

Question 15

How does the sliding filament theory work?

Answer 15

Calcium binds to Troponin, moves tropomyosin away from the actin binding sites

Question 16

What is Myasthesia Gravis?

Answer 16

Autoimmune destruction of the end plate Ach receptors, loss of junctional folds at the end plate

Question 17

What is Duchenns Muscular Dystrophy? What does it cause?

Answer 17

Genetic fault causing reduced synthesis of proteins that anchor actin filaments to the cell wall
Causes muscle fibers to tear themselves apart

Question 18

What is Malignant Hyperthermia? How does it cause this?

Answer 18

Life threatening reaction to some drugs used for anaesthetics
Causes an increase in Ca2+ release, this causes an increase in skeletal muscle metabolism. This overwhelms the bodies ability to supply O2 and remove CO2

Question 19

What is Multiple Sclerosis?

Answer 19

The removal of the Myelin sheath from around an axon + replaced with scar tissue