Biological Rhythms Flashcards
Circadian Rhythm (AO1)
A biological rhythm that reoccurs approximately every 24 hours. Eg sleep/wake cycle, core body temperature, hormone production.
Infradian Rhythm (AO1)
A biological rhythm that has a duration of over 24 hours, and maybe weekly, monthly or annual eg Human menstrual cycle, hibernation in bears and squirrels.
Ultradian Rhythm (AO1)
A biological rhythm that lasts less than 24 hours; eg the cycle of sleep stages that occur throughout the night. Eg. hunger/appetite, 90-minute sleep cycle
Endogenous pacemaker (AO1)
Mechanisms within the body govern then internal biological bodily rhythms
What is Suprachiasmatic nuclei (SCN)? (AO1)
A pacemaker that lies in the hypothalamus is the main endogenous pacemaker (or Master clock).
Exogenous Zeitgeber (AO1)
Environmental factors that help synchronise biological rhythms with the outside world; eg light onset which resets the circadian biological clock in the SCN.
Diurnal (AO1)
Circadian rhythm in which the animal is active during the day and quiet or asleep at night
Nocturnal (AO1)
Circadian rhythm in which the animal is active during the night and quiet or asleep during the day.
What are the three types of biological rhythms? (AO1)
- Circadian rhythm (every 24hrs)
- Infradian rhythm (more than 24hrs)
- Ultradian rhythm (under 24hrs)
What role does Light play in the sleep/wake cycle? (AO1)
Provides the primary input to this system, acting as the external cue for sleeping or waking. First detected by the eye which sends messages concerning the level of brightness to the SCN.
What is homeostasis? (AO1)
Refers to an organism’s ability to regulate various physiological processes to keep internal states steady and balanced.
What are the control systems for homeostasis? (AO1)
The endocrine and central nervous systems are the major control systems for regulating.
What part of the brain controls homeostasis? (AO1)
The hypothalamus.
What is the role of homeostasis in the sleep-wake cycle? (AO1)
Tells the body that there is a need for sleep because of energy consumption. Homeostatic drive for sleep increases throughout the day.
What does the pineal gland? (AO1)
The pineal gland regulates the production and release of melatonin
What is a Melatonin (AO1)
Secreted by the pineal gland. Production is influenced by the detection of light and dark by the retina of the eye.
- Involved in the regulation of sleep cycles (i.e circadian rhythm).
When does sleeping occur? (AO1)
When the core body temperature starts to drop and the body temperature starts to rise towards the end of a sleep cycle promoting feelings of alertness first thing in the morning.
What type of rhythm is temperature? (AO1)
Circadian rhythm