MEDICAL BIOLOGY, HUMAN ANATOMY, PHYSIOLOGY AND PATHOLOGY - Ya.I. Fedoniuk 2010

ANATOMY, PHYSIOLOGY, PATHOLOGY

SECTION 1. ORGAN. ORGAN SYSTEM. ORGANISM

CIRCULATORY DISORDERS

3. ISCHEMIA (LOCAL ANEMIA)

Ischemia (local anemia) is a decrease in the Blood supply to a tissue or organ resulting from inadequate arterial inflow, which leads to Hypoxia, or oxygen deprivation. Anemia can be either generalized or localized. Generalized anemia is caused by blood loss of various origins (Hemorrhage, anemia, etc.).

Local anemia presents in the following forms:

1. Angiospastic ischemia.

2. Obstructive ischemia.

3. Compressive ischemia.

4. Ischemia resulting from blood redistribution (dyscirculatory ischemia).

Angiospastic ischemia is caused by arterial spasm (angiospasm) resulting from increased tone of vasoconstrictor nerves, which can be observed upon exposure to low temperatures, certain chemicals (adrenaline), and other factors.

Obstructive ischemia is most commonly caused by atherosclerosis, thrombosis, or embolism, as well as Changes in the vessel walls themselves as a consequence of an inflammatory process, where the walls thicken and the lumen narrows. Compressive ischemia occurs As a result of tourniquet application, vessel ligation, external compression by a tumor, etc. Dyscirculatory ischemia is observed in cases of hyperemia following anemia, for instance, fluid removal during ascites is accompanied by cerebral anemia.

In the ischemic zone, tissue pallor, weakened arterial pulsation, and decreased Temperature are observed. Blood pressure in the arterial vessels drops, and blood flow velocity decreases. The patient experiences paresthesia: numbness, tingling, a "crawling" sensation, and sometimes severe pain.