biological rhythms - 20.01.24

Biological rhythms

Predictable patterns in physiological processes.

Adaptive significance

Advantage of anticipating environmental rhythmic events.

Exogenous rhythms

Rhythms generated by external environmental processes.

Endogenous rhythms

Rhythms generated by internal physiological processes.

Circadian rhythm

Daily biological cycle lasting approximately 24 hours.

Circalunar rhythm

Biological cycle aligned with lunar phases.

Circannual rhythm

Seasonal biological cycle over a year.

Locomotor activity

Common circadian rhythm related to movement.

Free-running rhythm

Oscillation unaffected by external time cues.

Entrainment

Adjustment of biological rhythms to environmental cues.

Melanopsin cells

Retinal cells involved in circadian light detection.

Suprachiasmatic Nucleus (SCN)

Master pacemaker regulating circadian rhythms.

Circadian-dependent change

Daily variations in hormone levels post-food intake.

Food Entrainable Oscillator (FEO)

Oscillator regulating feeding rhythms independent of SCN.

Clock genes

Genes controlling circadian rhythms in tissues.

Per1 signaling

Regulation of circadian rhythms in liver metabolism.

Clock KO mice

Mice lacking clock genes exhibit metabolic deficits.

Aberrant light exposure

Disruption of circadian rhythms due to unnatural light.

Constant light (LL)

Continuous light exposure affecting body mass.

Food timing impact

Timing of food intake influences body weight.

Night shift work

Work schedule disrupting normal circadian rhythms.

Metabolic dysfunction

Impaired metabolic processes linked to circadian disruption.

Diurnal mRNA rhythms

Daily fluctuations in mRNA levels across conditions.

Obesity association

Link between clock gene polymorphisms and obesity.

Dampened rhythms

Reduced rhythmicity in physiological processes during diseases.

ACTH

Adrenocorticotropic hormone, deals with stress responses including increased cortisol and fight or flight response

hormones

A chemical messenger that is released into the bloodstream or tissue fluid system that affects the function of target cells some distance from the source.

neurohormone

a hormone produced by neurons

neuropeptide

a peptide hormone produced by a neuron

neurosteroid

a steroid hormone produced by a neuron

neurotransmitter

a chemical messenger that acts across the neural synapse

summary of hormones

aromatase

aromatase levels and distribution governs most sex differences

examples of animal daily rhythms

Sleep

Mental performance

Autonomic nervous system

Hormone secretion

Blood pressure

Occurrence of disease symptoms & mortality (e.g. morning heart attacks)