Answer:
Exercise programs must increase in difficulty and duration to remain effective because of the principle of overload. As an individual exercises at a higher level, the body adapts to the increased demand and this higher level eventually becomes your body's new normal.
Explanation:
Answer:The five components of physical fitness are cardiovascular endurance, muscular strength, muscular endurance, flexibility and body composition
Explanation:
Answer:
d. Delivering each breath over 1 second
July 4th 1776 was United States Independence Day.
El 4 de julio de 1776 fue el Día de la Independencia de los Estados Unidos.
Answer:
1. spontaneously
2. resting potential
3. action potentials
4. pacemaker potentials
5. K+
6. Na+
7. into
8. Ca+
Explanation:
Pacemaker cells (also known as sinoatrial node cells) are cells that generate rhythmic impulses and set the pace for blood pumping in the heart. These cells have the ability to rhythmically depolarize and initiate action potentials. In pacemaker cells, Ca2+ and Na+ levels are higher in the extracellular environment, while K+ concentration is higher intracellularly. The pacemaker action potentials have three phases: 1-depolarization, where membrane potential reaches -40 mV and voltage-gated Ca2+ channels open, 2-repolarization, where voltage-gated Ca2+ channels close and voltage-gated K+ channels open, and finally 3-gradual depolarization, which is caused by the slow influx of Na+ ions.