Mechanisms of Disease

Question 1

headache

Answer 1

1. traction to or irritation of meninges and blood vessels
2. nociceptors stimulated by head trauma or tumors
3. blood vessel spasms, dilated blood vessels, inflammation and/or infection of meninges and muscular tension

Question 2

bronchial asthma

Answer 2

1. bronchoconstriction (inflamed airways respond to environmental triggers, produce excess mucus, then difficult breathing)
2. airway edema and inflammation
3. airway hyperreactivity
4. airway remodelling

Question 3

pneumonia

Answer 3

starts as URI, then moves to lower resp. tract; it is pneumonitis + consolidation (liquid in spaces normally filled w/ air)
1. viral: touching contaminated objects ->touching mouth/nose -> lungs -> airways -> alveoli;
or airborne droplets -> mouth/nose
2. bacterial: small aspirations of organism in throat/nose;

both can be spread through infected blood

Question 4

CHF

Answer 4

left: blood backs up in lungs -> resp. sx, fatigue, increased rate and laboured breathing, rales or cracks, pulmonary edema, cyanosis
right: ptting edema, ascites, liver enlargement
1. reduced efficiency of heart muscle, through damage or overloading
2. MI
3. hypertension
4. amyloidosis

Question 5

hypertension

Answer 5

1. excessive sodium and/or insufficient potassium intake -> excessive intracellular sodium -> contraction of vascular smooth muscle -> restricted blood flow -> higher pressure
2. increased resistance to blood flow w/ normal cardiac output -> structural narrowing of small arteries
3. disturbance in kidneys’ salt-water balance (renin-angiotensin) or abnormality of SNS

Question 6

myocardial infarction

Answer 6

1. rupture of atherosclerotic plaque on artery supplying heart muscle
2. impaired blood flow to heart -> ischemic cascade (heart cells in territory of blocked coronary artery die and do not grow back)

Question 7

chronic gastritis

Answer 7

1. body targets stomach as if foreign pathogen, makes antibodies against it, damages, or destroys stomach lining
2. bile enters through pyloric valve of stomach
3. may be caused by HIV/AIDS, Crohn’s, liver or kidney failure

Question 8

liver cirrhosis

Answer 8

1. development of scar tissue that replaces normal parenchyma -> blocks portal flow of blood through organ, raising BP and disturbing normal function
2. fibrous tissue bands separate hepatocyte nodules, which eventually replace entire liver architecture -> decreased blood flow

Question 9

diabetes

Answer 9

1. insulin deficiency or insensitivity
2. insufficient insulin -> glucose not absorbed properly -> not stored appropriately -> persistently high glucose levels, poor protein sysnthesis

Question 10

IBS

Answer 10

1. abnormalities in gut flora
2. psychosocial factors (anxiety, depression, sleep disturbance)
3. hormonal fluctuations in women

Question 11

jaundice

Answer 11

1. increased production of bilirubin, decreased hepatic intake, decreased conjugation
2. dysfunction of hepatocytes, slowing of bile egress from liver, obstruction of bile flow

Question 12

ischemic stroke

Answer 12

1. loss of blood supply to brain -> ischemic cascade -> failed production of ATP -> cellular injury and death

Question 13

hemorrhagic stroke

Answer 13

1. compression of tissue from expanding hematoma(s) -> pressure -> loss of blood supply to affected tissue; blood released by hemorrhage also has direct toxic effect on brain tissue

Question 14

Bell’s Palsy

Answer 14

1. malfunction of facial nerve (cranial nerve VII), usually inflammation

possible causes: meningitis, HIV, herpes, tumor, stroke, diabetes, head trauma, inflammatory diseases of cranial nerves

Question 15

Guillain-Barre Syndrome

Answer 15

1. immune attack on nerve cells of PNS and their support structures

Question 16

Meniere’s Disease (sx)

Answer 16

vertigo, tinnitus, hearing loss, fullness of ear

Question 17

sciatica

Answer 17

1. compression of lumbar nerves L4 or L5 or sacral nerves S1, S2, or S3

Question 18

trigeminal neuralgia

Answer 18

1. intracranial artery

2. venous loop that compresses the nerve (crainal nerve V) at its root entry zone into the brain stem

Question 19

rheumatoid arthritis

Answer 19

1. persistent cellular activation -> autoimmune response in joints and other organs where it manifests

Question 20

hemorrhoids

Answer 20

1. vascular cushions in anal canal either slide down; or

2. vascular cushions experience excessively increased venous pressure