Explanation:
The sinoatrial (SA) node, located in the right atrium, generates electrical impulses spontaneously and initiates each heartbeat, setting the rhythm. It is called the natural pacemaker. The atrioventricular (AV) node delays the impulse before it travels to the ventricles. The bundle of His and Purkinje fibers conduct the impulse through the ventricles.
Consider statements about plant biology: 1. Transpiration occurs through stomata. 2. Guttaion occurs through hydathodes. 3. Phloem transports water upwards. Which are correct?
Explanation:
Transpiration is the loss of water vapor primarily through the stomata on the leaf surface. Guttation is the exudation of liquid water from the margins of leaves through specialized structures called hydathodes, usually at night when root pressure is high. Phloem is responsible for the translocation of organic food (bidirectional), while xylem transports water and minerals upwards. Thus, statements 1 and 2 are correct.
Explanation:
The Bundle of His and Purkinje fibers are part of the electrical conduction system of the heart. The Bundle of His carries the electrical impulse from the atrioventricular (AV) node down the interventricular septum. It then divides into right and left bundle branches, which terminate in the Purkinje fibers. These fibers rapidly distribute the impulse throughout the ventricular myocardium, ensuring coordinated ventricular contraction.
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