Answer:
The sympathetic nervous system activates the 'fight or flight' response in an individual by releasing the hormones epinephrine and norepinephrine. These hormones increase the rate of the heart, respiration and dilates the pupils. This system is located in the spinal cord near the lumbar and thoracic area.
The parasympathetic nervous system found between the spinal cord and medulla, it activates the 'rest and digest' response by releasing the hormone acetylcholine, this hormone slows the heart rate as well as the respiration rate.
Explanation:
Answer:
The Autonomic nervous system, is a branch of peripheral nervous system (PNS) which controls involuntary activities of the body and the complimentary damping effects.Thus heart rate, response to fight-or flight stimulus,arousal, from sleep, digestion, breathing all are controlled by the ANS. Its control center in the brain is the Hypothalamus.
Sympathetic and Parasympathetic nervous systems(SNS&PSN) respectively are branches of ANS.while the SNS coordinate fast- response pathways to involuntary stimuli. thus it is usually refereed to as fight or flight system. The PNS is concerned with coordination of complimentary counter quick response to slowdown the effects of the quick response.
Based on orgin;
The PSN originated from the cranial and sacral region of the CNS system while; the SNS originated from the cranial, thoracic ,lumbar regions. The proximity to the SNS to these regions explains the reason for its regulation of digestion, respiration, urination, breathing,and other involuntary activities associated with these regions.
Ganglion distribution.
The PNS ganglion are located close to the effectors away from the CNS (Thus this explains the long-preganglion fibres, and short post-ganglion fibres of PNS.) The proximity with the effectors is to synapse quickly to bring into effects the motor response needed to counter the fast exitatory stimulation of the SNS at the effectors;e,g muscles.However SNS ganglion (shrot pre-ganlion fibres are in the CNS close to its control center in the medulla to coordinate fast response to rapid stimuli , to ensure effective response by the body,
Hormone influences
SNS stimulates and mediates the release of adrenaline from adrenal glands in response to fight or flight stimuli.This is needed to prepare the body for quick rapid response to danger or need for escape. However, the PNS has no effect on hormone release but maintain return of the body to normal physiological state after the effects of adrenaline
Homeostatic effects
Most excitatory homeostatic effects of the body are controlled the SNS.(thus the need to raise the water potential of the blood during dehydration is due to the excitatory effects of SNS to stimulate the release of ADH.) However the complimentary inhibitory effects to calm this down is coordinated by the PNS.
Thus while SNS increases heartbeat,heart-rate, adrenaline levels, metabolic rate, breakdown of glucose, through diffused effects at the target areas in repose to fast involuntary stimuli,
PNS, maintained a decrease in all these activities, by bringing calming effects at the localized area(effector).
Explanation:
