Circadian Rhythms Flashcards
How can the autonomic nervous system be split?
Enteric, sympathetic and parasympathetic
The control of temperature, blood pressure, hunger and satiety is via what axis?
The hypothalamic pituitary axis
The parasympathetic nervous system is characterised by certain axons, these are?
Long, unbranched, preganglionic neurones from the brainstem and spinal cord
Where is the parasympathetic ganglia located?
Close to their target organ
The sympathetic nervous system’s characteristic axon is…?
The short unbranched, preganglionic neurone from the thoraco-lumbar cord
The sympathetic ganglia is located where?
Close to the CNS
How do baroreceptors respond to an increased blood pressure?
Carotid artery and aorta stretch causes baroreceptors to increase their basal rate of action potential generation
Baroreceptor action potentials are conducted by which nerves?
The glossopharyngeal and vagus nerves
Where do the baroreceptors action potentials travel to?
The cardio regulatory and basso motor centres in the medulla oblongata
How does the cardio regulatory centre respond to increased action potentials?
Increases parasympathetic stimulation to the heart, decreasing heart rate and stroke volume
How does the cardiovascular centre react to the baroreceptors action potentials?
Decreases sympathetic stimulation, decreasing heart rate and stroke volume
Baroreceptors action potentials impact the vasomotor centre how?
Decreases sympathetic stimulation to blood vessels causing vasodilation
What is the purpose of the enteric nervous system?
Controls the GIT activity via the myenteric plexus
Where are the myenteric plexuses located?
GIT lining between the inner and outer layers of muscularis externa
How is the enteric nervous system innervated?
From the parasympathetic (vagus) and sympathetic chains
How is the enteric nervous system different to the other two branches?
It has the capacity to operate independently of the brain and spinal cord
How can the enteric nervous system function without CNS input?
It contains afferents, efferent and interneurones, so can initiate it’s own reflexes
Other than the myenteric plexus, what other plexus is involved in the enteric nervous system?
The submucosal plexus located in the submucosa
What characterises a circadian rhythm?
It must repeat once a day, persist in the absence of external cues and be able to adjust to time changes
How are circadian rhythms controlled?
Via the suprachiasmatic nucleus
What does the ascending reticular activating system involve?
Cholinergic, noradrenaline, serotonin and histamine neurones
The ARAS cholinergic neurones are located where are active when?
Pons and midbrain, active airing wake and REM sleep
NA, 5-HT and H neural systems of the ARAS are active when?
During wakefulness
What is known about sleep from EEG recordings?
It consists of 4 stages of non-REM followed by and REM period
Following the sleep stages, how does the EEG change?
The frequency decreases and the amplitude increases
Non-REM is also know as what?
Slow wave sleep
SWS has what physiological effects?
A decrease in muscle tone, heart rate and temperature
Why is REM sleep referred to as paradoxical sleep?
Because the EEG recordings are similar to those of the awake state
REM physiological changes are?
Similar to awake state, but lower motor neurones in the spinal cord are inhibited causing paralysis
How long is an individual in REM sleep for?
10 minutes
What are the three main reasons for sleep?
Ecological, metabolic and learning
How does an individuals sleeping pattern change as they get older?
The amount of sleep needed reduces with ages
