– Anal and Rectal
Left lateral, right anterior, and right posterior hemorrhoidal plexuses External hemorrhoids cause pain when they thrombose • Distal to the dentate line, covered by sensate squamous epithelium; can cause pain, swelling,…
– Hematology
NORMAL COAGULATION Three initial responses to vascular injury: vascular vasoconstriction, platelet adhesion, and thrombin generation Intrinsic pathway: exposed collagen + prekallikrein + HMW kininogen + factor XII ↓ activate XI…
– Neurosurgery
CIRCLE OF WILLIS Vertebral arteries – come together to form a single basilar artery, which branches into 2 posterior cerebral arteries Posterior communicating arteries – connect middle cerebral arteries to…
– Cell Biology
A lipid bilayer that contains protein channels, enzymes, and receptors Cholesterol increases membrane fluidity Cells are negative inside compared to outside; based on Na/K ATPase (3 Na+ out/2 K+ in)…
– Immunology
Helper T cells (CD4) • Release IL-2, which mainly causes maturation of cytotoxic T cells • Release IL-4, which mainly causes B-cell maturation into plasma cells • Involved in delayed-type hypersensitivity (brings in…
– Wound Healing
Inflammation (days 1–10) – PMNs, macrophages; epithelialization (1–2 mm/day) Proliferation (5 days–3 weeks) – fibroblasts, collagen deposition, neovascularization, granulation tissue formation; type III collagen replaced with type I Remodeling (3…
