Circadian Rhythms Flashcards
Where do sympathetic neurones arise from?
Spinal cord
Where do parasympathetic neurones arise from?
The brainstems cranal nerve
What are the features of the enteric nervous system?
Work autonomously but can receive parasympathetic and sympathetic innervation, consists mainly of myenteric plexus.
What three properties must circadian rhythms have?
Repeat at least once per day, persist in the absence of external cues, adjust to local time
Where in the brain are circadian rhythms controlled?
The suprachiasmatic nucleus- above the optic chiasm in the thalamus.
What is the pathway of sleeps circadian rhythm?
Photoreceptors to retinal ganglion cells to the hypothalamus, to the intermediolateral cell column, up the superiors cervical ganglion to the pineal gland and melatonin.
What six things are controlled by circadian rhythms?
Sleep, alertness, cortisol, growth hormone, temperature and potassium
How does frequency and amplitude change throughout the sleep stages?
Awake until stage 4, then frequency decreases and amplitude increases
What waves are used for:
a) awake and active
b) awake
c) 1,2 and 3
d) 4?
a) alpha
b) beta
c) theta
d) delta
Hat decreases during non-REM sleep?
Physiological function
Which REM or non-REM sleep is deeper?
Non-REM sleep, stage 4
Why do we sleep?
For ecological, metabolic and learning reasons.
What is the hypothalamus directly linked to and why?
The pituitary gland, as it controls the release of many hormones
Give the two types of neuroserectory cells of the pituitary gland?
Mangocellular and parvocellular
What are the differences between magnocellular and parvocellular?
Magnocellular- are bigger, the hormones are released directly into the bloodstream and the axons project into the posterior lobe
Parvocellular- axons project into the anterior lobe and the hormones are released in two stages.
Give and example of a magnocellular?
ADH- when blood pressure is low renin is secreted to convert angiotensin to angiotensin 1 and then 2.
Give and example of a parvocellular?
Cortisol- ACTH is released to cause direct cortisol release from the adrenal gland.
How is alertness controlled?
By an ascending reticular activating system
What do brain stem lesions lead to?
Sleep and coma
What does EEG stimulation cause?
Non-REM sleep to alert/awake form
What neural systems are activated during wakefulness?
Noradrenaline, serotonin and histamine.
What activity do cholinergic neurones in pons/midbrain border have: a) during waking and REM sleep and b) during non-REM sleep?
A) high
B) inactive
What effect thalamo-cortical projections and cause them to be more polarised?
Cholinergic, serotninergic and neuroadrenergic projections
What do EEGs measure?
Neural (electrical) activity
What are the six stages of sleep?
Awake, 1, 2, 3, 4 and REM
What is the hypothalamic pituitary axis important for?
Temperature control, blood pressure and hunger/satiety
What is the hypothalamic pituitary responsible for?
The control of secretion of many hormones
What is the enteric nervous system?
A subdivision of the autonomic NS
What does the enteric NS do?
Works autonomously to control the activity of the GI tract
