6.8.2 Infradian Rhythms

• What are infradian rhythms?

  Biological rhythms > 24 hours
• Infradian rhythms have a period longer than 24 hours.
• Order the phases of the menstrual cycle.

  1️⃣ Menstruation

  2️⃣ Follicular phase

  3️⃣ Ovulation

  4️⃣ Luteal phase
• What is the approximate length of the menstrual cycle?

  28 days
• Infradian rhythms are regulated by both internal biological clocks and external environmental cues.
• How long does the menstrual cycle typically last?

  28 days
• Seasonal migration in animals is driven by factors like weather and food availability.
• What does SAD stand for?

  Seasonal Affective Disorder
• Seasonal Affective Disorder is linked to seasonal changes.
• What is regulated by the menstrual cycle?

  Hormone production and ovulation
• Animal migration is influenced by weather and food availability.
• What is the approximate duration of the menstrual cycle in days?

  28 days
• What type of biological clocks regulate infradian rhythms?

  Internal biological clocks
• Circadian rhythms have a period of exactly 24 hours.
• Infradian rhythms occur over periods longer than 24 hours
• What is the role of hormonal signals in the menstrual cycle?

  Regulate biological processes
• Phases of the menstrual cycle in the correct order

  1️⃣ Menstruation

  2️⃣ Follicular Phase

  3️⃣ Ovulation

  4️⃣ Luteal Phase
• Which hormone increases during the follicular phase?

  Estrogen
• What is the typical season when SAD occurs?

  Winter
• Infradian rhythms have a period shorter than 24 hours.

  False
• What is an example of a circadian rhythm?

  Sleep-wake cycle
• Match the type of rhythm with its period length:

  Ultradian ↔️ Less than 24 hours

  Circadian ↔️ 24 hours

  Infradian ↔️ Weeks to years
• What environmental cue influences infradian rhythms in seasonal migration?

  Weather changes
• The menstrual cycle is an example of an infradian rhythm with a period of approximately 28 days.
• Seasonal Affective Disorder (SAD) is primarily caused by reduced exposure to sunlight.
• Which hormone triggers ovulation during the menstrual cycle?

  Luteinizing Hormone (LH)
• Which hormone triggers ovulation in the menstrual cycle?

  Luteinizing Hormone
• Estrogen promotes the thickening of the uterine lining.
• What is the primary role of progesterone in the menstrual cycle?

  Maintains pregnancy
• Seasonal migration is influenced by hormonal regulation.
• Hormonal regulation of infradian rhythms involves cycles longer than 24 hours.
• Which hormone stimulates follicle growth during the menstrual cycle?

  Follicle-Stimulating Hormone
• Infradian rhythms are influenced by both internal and external factors.
• Environmental cues such as light and temperature are examples of external factors affecting infradian rhythms.
• Types of research methods used in infradian rhythm studies

  1️⃣ Observational Studies

  2️⃣ Experimental Studies

  3️⃣ Longitudinal Studies
• Match the research method with its key feature:

  Observational Studies ↔️ Records natural behaviors

  Experimental Studies ↔️ Manipulates variables

  Longitudinal Studies ↔️ Tracks over time
• Seasonal Affective Disorder (SAD) is linked to seasonal changes in light.
• What is the period length of infradian rhythms?

  Longer than 24 hours
• External environmental cues can influence infradian rhythms.
• Match the rhythm type with its period length:

  Circadian ↔️ 24 hours

  Ultradian ↔️ Less than 24 hours

  Infradian ↔️ Greater than 24 hours