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Parts of the brainstem?
Midbrain, pons, medulla oblongata
Vegetative functions of the brainstem?
respiration, cough and gag reflex, pupillary response, swallowing response, heartbeat, blood pressure, etc.
What does the brainstem connect?
the brain and spinal cord
What are the three divisions of the autonomic nervous system?
Functions of the ANS?
innervates internal organs, blood vessels, glands; regulates cardiac and smooth muscle, regulates secretion from glands, controls vegetative functions (involuntary), controls visceral reactions, influences muscle tone through motor tracts
where does the PSNS neuron fibers emerge from?
the brainstem and sacral spinal cord
what is increased during alerting situations and restful situations?
alerting: SNS
restful: PSNS
where do SNS neuron cell bodies hang?
intermediolateral horn of the thoracic and L1-L2 lumbar sections of the spinal cord
What are the two main neurotransmitters?
NE= norepinephrine
Ach= acetylcholine
what is the SNS? and some physiological responses?
activates the fight/flight response during situations of stress or perceived threat; increased HR and BP, increased blood sugar levels, pupil and bronchioles dilation, blood flow to muscles and brain, constriction of stomach/intestine/internal sphincter
what is the PSNS? and what are its functions?
response for energy conservation, storage, and replenishment (rest and digest); regulates homeostasis and slows the body down; slows HR, stimulates digestion, constricts pupil, stimulates insulin release, slow respiration, stimulates contraction of bladder
what is the difference between the physiological arousal level and optimal arousal level?
the state of activation or stimulation of the body's physiological systems
perform occupations with efficiency, effectiveness, focus, motivation
what happens if the physiological arousal level is too high or too low?
impact on occupational performance; cognitive function/decision making, focus and attention, fine motor skills, motor control, stress, fatigue
zone of optimal arousal
inattention, reduced vigilance, sleepiness >> optimal task-performance >> exploratory behaviors, distractibility, stress
reticular formation? involved in?
internal core of brainstem consists of complex set of neuronal groups (network of neurons throughout brainstem)
modulation of sensory transmission to the cortex, maintain attention/arousal, regulation of motor activity/posture, autonomic regulation (connected with the hypothalamus), sleep and wakefulness cycles, modulation of emotional behavior
reticular activating system (RAS)
portion of reticular formation responsible for arousal, alertness, wakefulness; filters all incoming sensory information; alerts cortex to attend to important sensory input (sharpens our attention)
What sensory input CALMS the body by influencing inhibitory functions in the RAS?
PSNS
SNS
what is the stress response?
experience a stressful event > the amygdala and limbic system process the emotion and initiate a fear response > the amygdala sends a distress signal to the hypothalamus > signals sent through ANS to adrenal glands to secrete epinephrine (activates the SNS) OR activates the HPA Axis by secreting hormones to the pituitary gland which sustains the gas pedal on the SNS
what is the hypothalamus?
central control center of the ANS (THE BOSS) regulates in response to internal and external changes; releases hormones from the pituitary/adrenal/pineal gland; regulates temperature, hunger and thirst, sleep-wake cycles and fatigue; works with the limbic system in expression of emotions
hypothalamus and pituitary gland
hypothalamus secretes hormones to the posterior and anterior pituitary
P then secretes the same hormones into the bloodstream
A then secretes its own hormones
heightened emotional state? agitated or nervous? Just saw your crush and you are blushing, have heart palpitations, clammy hands, and a dry mouth?
activated SNS and dampened PSNS
loss of appetite=suppression of digestion (activated SNS)
Due to link between the limbic system and the ANS
Hypothalamic Pituitary Adrenal Axis (HPA Axis)
stress from environment > hypothalamus > corticotropin releasing hormone > anterior pituitary > adrenocorticotropic hormone > adrenal cortex > cortisol > hippocampus > hypothalamus
HPA Axis Dysfunction
Chronic stress, Childhood trauma, Poor diet, Disrupted circadian rhythms, Mental health conditions, Loss of a loved one, Oxidative stress, Cardiovascular diseases
how should the HPA axis turn on and off?
HPA axis should turn on in response to stress- leading to the release of cortisol
HPA axis should turn itself off through the negative feedback loop when the stressful event has been dealt with- stopping the release of cortisol