ANS Flashcards
The ANS controls […]
Visceral organs
What are the three major divisions of the ANS?
Sympathetic
Parasympathetic
Enteric
What type of tissue does each division of the ANS innervate?
Sympathetic: cardiac and smooth
Parasympathetic: cardiac and smooth
Enteric: digestive tract
The sympathetic system is activated in […] reactions.
emergency fight-or-flight
The parasympathetic system is activated in […] reactions.
Rest and digest
When are the sympathetic system and parasympathetic system active?
They are both active all the time, but in different proportions depending on the situation.
What are the two types of neurons present in the sympathetic system?
Preganglionic and postganglionic neurons
The preganglionic cells in the sympathetic nervous system originate in the […]
Ventral roots of the thoracic and lumbar regions of the spinal cord
The postganglionic cells in the sympathetic nervous system originate in the […]
Sympathetic ganglia
What is the sympathetic ganglia? What does it allow?
The chain runs along either side of the spinal cord where the pre and postganglionic neurons synapse in the sympathetic nervous system.
It allows the sympathetic system to act as a coordinated unit
Compare the structure of the preganglionic sympathetic neuron and the postganglionic sympathetic neuron.
Because the preganglionic sympathetic neuron synapses on the ganglia right outside of the spinal cord, its axons are quite short.
The postganglionic neuron has a long axon, because it must go from the ganglia all the way to the organ.
Sympathetic preganglionic neurons release […], which activates […] on […]
Acetylcholine, nicotinic acetylcholine receptors, postganglionic neurons
Sympathetic postganglionic neurons release […], which activates […] on […]
Norepinephrine, alpha and beta-adrenergic receptors, target organs
Explain how beta blockers work.
Norepinephrine activates alpha and beta-adrenergic receptors. Beta-blockers for the heart prevent the sympathetic nervous system from increasing your heart rate by preventing the activation of beta-adrenergic receptors.
What type of receptors are alpha and beta adrenergic?
Metabotropic receptors
Explain how alpha and beta adrenergic receptors affect their target cells.
The second messengers sent by the G-protein coupled receptor will change the physiology of the cells of the target organ
The axons from parasympathetic preganglionic neurons emerge from […]
Brainstem
Compare the structure of the preganglionic parasympathetic neuron and the postganglionic parasympathetic neuron.
The preganglionic neurons are very long as they need to reach the target cell whereas the postganglionic cells are shorter since they only contest the preganglionic cell with the target cells.
Parasympathetic input to the visceral organs is provided by the […]
Vagus nerve (Xth cranial nerve)
Parasympathetic input to the eye is provided by the […]
Oculomotor nerve (IIIrd cranial nerve)
Preganglionic parasympathetic neurons release […], which activates […]
Acetylcholine
Nicotinic acetylcholine receptors
Postganglionic parasympathetic neurons release […], which activates […]
Acetylcholine
Muscarinic acetylcholine receptors
What type of receptor is a muscarinic acetylcholine receptor?
Metabotropic
Describe how the sympathetic and parasympathetic systems affect the heart.
Sympathetic: Accelerate the heart
Parasympathetic: Slow down the heart
The human enteric system contains […] neurons. How does this compare to the spinal cord?
about 100 million
About the same amount as in the spinal cord
Describe the relationship between the enteric system and the parasympathetic and sympathetic systems.
It is modulated by the other two autonomic nervous systems.
What are the two types of neurons in the enteric nervous system?
Cholinergic and adrenergic
What do cholinergic neurons do in the enteric nervous system?
Activate the peristaltic contractions
What do adrenergic neurons do in the enteric nervous system?
suppress the gut peristalsis
How does most sensory information from visceral nerves reach the ANS?
By the vagus nerve
How does visceral sensory information from the head and neck reach the ANS?
Glossopharyngeal and facial nerves
What are the two layers of neurons in the intestine and what do they do?
Myenteric plexus: controls contractions of smooth muscles
Submucous plexus: controls intestinal secretions
Describe the path and hierarchical structure of responses to visceral sensory inputs by the ANS.
The input travels from the organ to the brainstem nuclei, then projects to higher brain centers involved in homeostasis. The higher levels modulate the output of the lower levels based on information integration, while the lower levels (brainstem) is responsible for the execution.
What are the main higher centers involved in control of the ANS?
Hypothalamus, amygdala and cerebral cortex
What is the role of the hypothalamus in the regulation of the ANS?
It integrates autonomic responses and endocrine function with behaviour in order to maintain homeostasis.
What are the 3 components of the hypothalamus’ control of the body?
It controls the autonomic response, the behavioural response (through the cerebral cortex), and the hormonal response (through the pituitary gland).
Give examples of the three components of the body to exposure to cold temperatures.
ANS response: shivering, change in blood flow, etc.
Cerebral response: motivation to warm up
Hormonal response: secretion of hormones that will warm the body
What are the 5 physiological needs that the hypothalamus regulates?
Blood pressure and electrolyte balance
Body temperature
Energy metabolism
Reproduction
Emergency response to stress
How does the hypothalamus evaluate sensory information to produce a response?
It uses biological set points. When it detects a deviation from the set point, it coordinates autonomic, endocrine, and behavioural responses to restore homeostasis.
The autonomic nervous system and hypothalamus interact with other brain regions, including […].
the amygdala and the ventral-medial parts of the cerebral cortex
What is the effect of the connection between the hypothalamus and the amygdala?
They relate visceral responses to conscious feelings and connect emotions to memories
Where is the amygdala located on brain?
In the uncus, which is on the underside of the brain under the hippocampus.
If someone doesn’t have an amygdala, how will their functioning differ?
People without amygdalas won’t have a physiological response to the emotions they might experience, such as sweating, feeling nervous, etc.
What is the effect of the connection between the ANS and the ventral-medial pre-frontal cortex?
These regions of the cerebral cortex are important in connecting physiological states with conscious feelings and emotions. This is why we can feel anxious because of things that aren’t a direct threat to us and are instead social constructs.
If someone has damage to their ventral-medial pre-frontal cortex, how will their behaviour differ?
This will prevent the ability to regulate emotion and connect it with events in life. This will lead to poor social judgment.
