Transverse tubule
- Invaginations of the muscle cell membrane that contain dihydropyridine receptors.
- When they depolarize they allow the impulse to propagate through the interior of the
muscle fiber
- Allows for synchronized contraction of myofibrils in each muscle cell
Growth hormone
- In tissues: increases insulin resistance, fat utilization, protein synthesis
- In liver: increases IGF-1 production  growth and development
- Works via JAK/STAT pathway (non receptor tyrosine kinase)
Burns
- Superficial burns morphological changes occur due to tissue damage and inflammatory
mediators such as Mast cells, which release histamine (dilates capillaries in the skin)
- Deeper burns may damage nerve and venules. Can create a blistering due to fluid
extravasation through gaps between injured venule endothelial cells
Nonseminomatous germ cell tumor
- Undiff/ partially differentiated germ cells
- Usually make abnormal hormones (AFP, hCG)
- Solid mass in testicle
Lead poisoning
- Microcytic anemia, constipation, mental status changes
- Shortness of breath due to decreased oxygen delivery to peripheral tissues
- Lead inhibits ALAD, and ferrochelatase
- Will see basophilic stippling on Blood smear
-
Wilson Disease
- Autosomal recessive, ATP 7B mutation. Damage from increased copper accumulation,
deposition into various tissues
- Increased urinary copper excretion, decreased ceruloplasmin.
- Kayser-fleischer rings detected on silt lamp examination .
- Tx: Chelators like penillamine, trientine,… Zinc
Types of muscles fibers
- Type 1 = slow twitch
o Sustained contractions. Generate energy through aerobic metabolism
o High myoglobin and mitochondrial concentrations
o i.e. Postural muscules
- Type 2 = fast twitch
o Derive ATP from anerobic glycogenolysis and glycolysis
o Rapid, forceful movements (biceps, deltoid etc.)
GIST : Gastrointtestinal stromal tissue
- Normally present in the sixth decade as gastric bleeding or obstruction
- Spindle shaped cells on histology
Echinococcus Granulosus