A flexor reflex, which is also called a withdrawal reflex, is a multisynaptic reflex. It is a type of protective reflex where a painful stimulus triggers the contraction of flexor muscles. These reflexes have a slower onset and a longer response than the stretch (extensor) reflexes. A flexor reflex requires the contraction of a flexor muscle and relaxation of the extensor muscle in that limb. A good example of a flexor reflex is when you touch your forearm to the side of a hot oven.
Causes of Hypoxia. A severe asthma attack, or flare, can cause hypoxia in adults and kids. During an attack, your airways narrow, making it hard to get air into your lungs. Coughing to clear your lungs uses even more oxygen and can make symptoms worse. Other things can cause hypoxia, too: 1  Lung diseases such as chronic obstructive pulmonary disease (COPD), emphysema, bronchitis, and pulmonary edema (fluid in the lungs). 2  Strong pain medicines and other drugs that hold back breathing.
Hypoxic hypoxia (hypoxemic hypoxia) â- In this type of hypoxia, the tissues do not have enough oxygen because there is a lack of oxygen in the blood flowing to the tissues. Hypoxic hypoxia can be caused by inadequate breathing as well as other causes. Anemic hypoxia -- In the setting of anemia, low hemoglobin levels result in a reduced ability of the blood to carry oxygen that is breathed in, and hence, a diminished supply of oxygen available to the tissues.