Autonomic nervous system Flashcards
What does the autonomic nervous system control?
The visceral organs (soft internal organs of the body)
Main role of the autonomic nervous system?
Maintenance of homeostasis
What are the three major divisions of the autonomic nervous system? +role of each
Sympathetic
Parasymapthetic
-Both for innervation of cardiac&smooth muscle and glandular tissue
Enteric
-digestive tract
Overarching role (goal kind off) of the sympathetic and parasymapthetic systems?
Effect that THEY BOTH have on a target tissue
Opposing effects on target tissue:
-sympathetic: especially activated in fight or flight reactions
-parasympathetic: especially involved in rest-digest processes
Where do sympathetic preganglionic neurons originate and project to?
From the ventral roots of the thoracic and lumbra region, to their target neurons
What is located between preganglionic neurons and post ganglionic neurons (sympathetic)? Where within the overall nervous system?
Synapses that are clustered in a chain of sympathetic ganglia running along either side of the spinal cord
What do sympathetic preganglionic neruons release? What doe they activate? Where?
Acetylcholine, activating nicotinic acetylcholine receptors on postganglionic neurons
What do sympathetic postganglionic neurons release? Activates what on what?
Norepinephrine, activating alpha and beta adrenergic receptors on target organs
Where do the axons of the parasymapthetic neurons emerge from? Where do they extend to?
-The brainstem (cranial nerves 3, 7, 9, 10) and the sacral spinal cord
-Extend almsot all the way to peripheral targets
-Remaining distance covered by postganglionic neurons
What provides parasympathetic input to the visceral organs?
Vagus nerve
What innervates the salivary glands?
Facial and glossopharyngel nerves
What innervates the smooth muscle responsible for contraction and relaxation of the pupils?
Oculomotor nerve
What innervates the bladder, large intestine and reproductive organs?
Parasympathetic projections from the sacral spinal cord
but like also im pretty sure the symapthetic system
What do parasympathetic preganglionic neurons release? What does that activate? What about postganglionic neurons?
-Acetylcholine
-Postsynaptic nicotinic acetylcholine receptors
-Acetylcholine
-Muscarinic acetylcholine receptors on the target organ
What joint effect do sympathetic and parasympathetic neurons have on target tissues?
Opposing effects
What controls the digestive tract?
The enteric system
What does the enteric nervous system control? (3)
GI tract, pancreas and gallbladder
What components of the GI, pancreas and gallbladder does the enteric nervous system control
Smooth muscle in the gut as well as blood vessels and secretion by mucosa
How many neurons are in the human enteric system? Comparable to what other part of the nervous system?
100 million neurons, similar to spinal cord
Where the enteric nervous system receive input from?
Sympathetic and parasympathetic, but is highly autonomous and does not need external neuronal output
Three types of neurons in the enteric system + roles
-Cholinergenic neurons: activates peristaltic contractions of the gut
-Adrinergenic neurons: supress gut peristalsis
-Neurons releasing neuropeptides, ATP and nitrous oxide
Intestine morphology, from outside to inside + role
-Longitudinal smooth muscle : longitudinal contraction
-Myenteric plexus: control smooth muscle contraction
-Circular smooth muscle: circular contraction
-Submucous plexus: controls secretions
-Mucosa
-Lumen (inside)
How does the sensory info from the visceral organs reach the autonomic nervous system?
Via the Vagus nerve or by inputs into the spinal cord
How does the sensory info from the head and neck reach the autonomic nervous system?
Glossopharyngeal and facial nerves
What mediates the direct autonomic reflexes and projects to higher brain areas? And what doe the higher brain areas do?
Brainstem regions
Coordinate autonomic responses
Role of the hypothalamus in the autonomic nervous system?
Integrates autonomic responses
Coordinates endocrine function and hormone release (and thus behaviour)
**maintenance of homeostasis
What 5 basic needs does the hypothalamus regulate?
-Blood pressure / electrolyte balance
-Body temp
-Energy metabolism
-Reproduction
-Emergency response to stress
How does the hypothalamus work to maintain homeostasis? Description of overall process
Compares sensory info to set biological points (think body temp example)
What other regions of the brain do the hypothalamus and autonomic nervous system interact with?
Cerebral cortex, amygdala, pituitary gland
**hypothalamus interacts with everything, autonomic just with hypothalamus and amygdala
