IMED1001 Study Guide - Final Guide: Neurovascular Bundle, Vena Comitans, Ischemia
IMED1001: Tutorial Week 3 Notes
Anastomoses:
-Joining of hollow structures!
-When branches of arteries anastomose = can provide alternative paths for circulation !
-This is used for when there is a blockage (atherosclerosis for example)!
-Extensive anastomoses = example intestines !
-Also can be seen in joints of limbs!
-Little/no arterial anastomoses = eg. Heart and brain!
Blockage of Blood Vessels:
-Anastomoses doesn’t guarantee tissue survival!
-Depends on these factors:!
1. Size of anastomosis!
2. Sudden or gradual blockage?!
3. Tissue resilience!
-Eg. Of intestine!
-Profuse anastomoses - but still suffer blockages!
-Eg. Of brain!
-Nervous tissue is very sensitive!
Vascular Disease:
-= When there is a disease of arterial wall!
-= causes narrowing of BV!
-STENOSIS!!
-This cuts off blood supply to certain organs!
-Distal tissues can get ischaemia!
-When thrombus is being dislodges = embolus!
-When embolus = can get stuck in narrow BV = embolism!
-Weakened arterial wall can cause aneurysm (there is a risk of rupture)!
Veins and Valves:
-Valves present for maintaining unidirectional blood flow!
-Prevents back flow of blood!
-Most parts of body have SUPERFICIAL and DEEP veins!
-Venous anastomoses more common than arterial!
-Lower limbs: there is flow against gravity !
-Muscles help with this problem!
-There is a communication between deep and superficial muscles to help overcome
gravity!
-When calf muscles relax, blood is ‘sucked’ into deep veins from superficial veins!
-Blood is then pumped upwards towards heart when muscles contract!
Document Summary
When branches of arteries anastomose = can provide alternative paths for circulation. This is used for when there is a blockage (atherosclerosis for example) Also can be seen in joints of limbs. Little/no arterial anastomoses = eg. heart and brain. Depends on these factors: size of anastomosis, sudden or gradual blockage, tissue resilience. Profuse anastomoses - but still su er blockages. = when there is a disease of arterial wall. This cuts o blood supply to certain organs. When thrombus is being dislodges = embolus. When embolus = can get stuck in narrow bv = embolism. Weakened arterial wall can cause aneurysm (there is a risk of rupture) Valves present for maintaining unidirectional blood ow. Most parts of body have superficial and deep veins. Lower limbs: there is ow against gravity. There is a communication between deep and super cial muscles to help overcome gravity. When calf muscles relax, blood is sucked" into deep veins from super cial veins.
