15 Examples of Biological Rhythms

The biological rhythms they are periodic changes that occur in organisms, at regular intervals of time. For example: heartbeat, brain waves, menstrual cycle.

All organisms experience biological rhythms, which can be:

Although it is considered that some rhythms are intrinsic because they have been observed in laboratory conditions (isolation of external factors), in the normal development most of the biological rhythms of organisms are affected by both internal and external factors.

They are called synchronizers to environmental factors that are capable of varying endogenous rhythms.

Types of biological rhythms

Examples of biological rhythms

1. Heartbeat. Two-phase pumping action, performed by the heart.

The heartbeat can vary in its rhythm depending on the body's operating conditions (physical activity, rest) and context (stressful situations, temperature changes). That is to say that it is a biological rhythm only relatively constant.

1. Respiratory movement. The breathing It is associated with the heart rhythm, since it is a biological rhythm that allows the blood to be oxygenated. There are two types of respiratory movements.
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While the air is in the lungs, the exchange of gases It allows the blood to be oxygenated and to eliminate gases that are harmful to the body.

In the same way that occurs with the heart rhythm, the respiratory movement is modified by the body needs, so its rhythm is usually constant but not invariable.

1. Brain waves. Electrical activities produced by the brain. Their rhythm is measured in cycles per second (Hz). According to each mental state, different types of wave are produced:

1. Sleep - wakefulness. Related to the nitameral rhythm (day-night). It depends on the external influences of light, noise and movement that we usually experience during the day. It has been observed that without external influences this rhythm exceeds the duration of one day (from 25 to 29 hours). For this reason, there is the phenomenon of “jet lag”, the change in the rhythm of sleep when traveling to a territory with an alternation of light and darkness very different from the original one. In other words, the synchronizers of this biological rhythm are the alternation of light and darkness and environmental factors (work obligations, activities, etc.).
2. Menstrual cycle. Process that prepares the uterus of women and female animals for pregnancy. In women, the menstrual cycle lasts 28 days on average (some women have shorter cycles and others longer).
3. Seasonal affective disorder. It is a mood disorder that appears at a certain time of the year. The most common is that it occurs in winter or at the end of autumn. It is associated with major depressive disorder. exist hypothesis that it is due to a brain response to a decrease in natural light, lowering the levels of serotonin and melatonin (substances that regulate mood).
4. Crustacean activity on marine beaches. Much of the crustaceans they have behaviors that respond to the tidal cycle. For example fiddler crabs gather on mud banks at low tide, digging a hole where they will remain when the tide rises.
5. Feeding. The sleep-wake rhythm affects all other bodily functions, as it modifies body temperature, blood pressure, and the secretion of hormones such as melatonin. That is why all organs of the digestive system. The intestine, for example, is more active during the day. The hormones responsible for regulating intake (leptin and adiponectin) vary depending on the time of day. However, as we have already observed, biological rhythms are affected by factors external to the organism, related to social, work and cultural activities. Therefore, traditions Every day of each person activate the digestion mechanisms at the times when they eat regularly.
6. Reproductive rhythms. Reproductive rhythms vary in each species. For example, most temperate animals have reproductive periods only at certain times of the year. These animals have a seasonal reproduction. This is due to a adaptation natural to the time when the environment is more conducive to the birth of the young.
7. Seasonal migrations. Seasonal migrations are periodic displacements of a habitat to another. Different classes of animals carry out seasonal migrations: birds, fish, lobsters, amphibians and mammals. Migrations can have the objective of moving away from extreme climates (that is why they are always carried out in the same time of year) or to reach a place conducive to breeding (as is often the case with fishes). Migratory movements tend to cover greater distances in birds, which even change from one contain to another (such as swallows that migrate from Europe to Africa).
8. Hibernation. It is a state of lethargy that allows animals to adapt to extreme cold. It can last for days, weeks or months. It allows them to conserve energy during times when food is scarce, slowing metabolism significantly. Other biological rhythms also decrease during hibernation, such as respiration, heart rate, and brain waves. Among the mammals that hibernate are the marmot, the dormouse, the hedgehog, the ground squirrel, the hamster and the bat.
9. Winter torpor of reptiles and amphibians. The reptiles They are cold-blooded animals (heterothermic) so they usually do not go through a period of hibernation. However, some reptiles and amphibians go through a process similar to hibernation, during which they remain protected in burrows in a state of torpor.
10. Summer lethargy of desert mammals. While the best known periods of torpor are hibernation, which occurs in winter, other mammals can defend themselves from extremely high temperatures in the desert through a period of lethargy that occurs during the summer (summertime). The gerbil, for example, goes into a lethargy in times of higher temperatures.
11. Flowering in plants. In most of the plants with flowers, they begin to grow in early spring. This is due to a natural adaptation, which makes plants genetically ready to flower when temperatures begin to rise. It is not yet known how plants perceive these changes in temperature.
12. Tubing in plants. Tuberization is the process by which the roots or lower parts of the stem of a plant develop into tubers, such as potato (potato) or sweet potato (sweet potato). The tuberization depends on certain hormones of the plant. The beginning of its growth occurs between 15 and 28 days after sowing, and lasts between 10 and 14 days, usually the days before the flowering of the plant. Although this is a relatively stable biological rhythm, it is affected by both internal factors (whether the plant arises from a new or old seed, for example) and external factors (light, nutrients available, humidity, temperature).