Answer:
Empty calories are foods that are low in nutrients and high in calories.
Explanation:
Empty calories are foods that have little nutritional value, they otherwise give the body solid fats and more sugar content leading to weight gain and deficiencies in nutrients.
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.
