6 Flashcards
Function of ANS
influenced by hypothalamus, maintains homeostasis - maintenance of an optimal internal environment
Regulates activity of internal organs and vasculature
Receptors of ANS
Mechanoreceptors
Chemoreceptors
Nociceptors
Thermoreceptors
Receptor that responds to pressure (aortic arch, carotid sinuses, and lungs) and stretch (distension of veins, bladder or intestines
Mechanoreceptors
Sensitive to chemical concentrations in blood located in carotid and aortic bodies (oxygen) medulla (hydrogen ions and carbon dioxide) and hypothalamus (blood glucose levels and electrolytes)
Chemoreceptors
Found throughout viscera and wall of arteries
most responsive to stretch and ischemia
Nociceptors
In hypothalamus responds to small changes in temp of circulating blood
Thermoreceptors
How info from visceral receptors enter CNS
Into spinal cord via dorsal root
Into brainstem via CN VII, IX and X
all three transmit taste, IX and X transmit info from viscera
Central regulation
Visceral infor converges in brainstem via solitary nucleus
Relayed to visceral control areas in pons and medulla
Relayed to modulatory areas in hypothalamus, Thalamus and limbic system
What does the medulla regulate through central regulation
HR, Respiration, Vasocontriction/dilation by signals to autonomic efferent neurons in spinal cord and vagus nerve
What does the pons regulate through central regulation
Respiration
Hypothalamus, thalamus, and limbic system modulate
Brainstem autonomic control
Visceral info sent from the thalamus is projected to
Limbic system
Hypothalamus: the overseers of ______
Homeostasis and ANS
Many regions of the brain supply the hypothalamus with info, but only the _______________ send sensory info directly to the hypothalamus
Olfactory system and small part of the visual system
Function of the limbic system
Emotion and memory
Influences motor and autonomic output via emotion
What composes the limbic system
Hypothalamus Nuclei of thalamus Limbic cortex Hippocampus Amygdala
Subsystems of the efferent pathway
Sympathetic
Parasympathetic
Fight or flight system
Sympathetic
Rest and digest system
Parasympathetic
Where are cell bodies of the sympathetic preganglionic neurons located?
Lateral horn T1-L2
Primary function of the sympathetic system
Maintain optimal blood supply to organs
Regulate body temp and metabolic rate, and activity of viscera
Where are the preganlionic cell bodies of the parasympathetic system located
Brainstem (nuclei of CN III, VII, IX and X) and sacral spinal cord (S2-S4)
Primary function of the parasympathetic system
energy conservation and storage
Decreases cardiac activity, facilitates digestion, and regulates activity of viscera
Loss of vascular control, temp regulation, and sweating, may lead to trophic changes in the skin
ANS correlation with peripheral nerve injury
Disrupts ascending and descending autonomic signals at level of lesion
ANS correlation with Spinal region injury
complete lesion S2-S4 or cauda equina produces
flaccid bladder
A lesion above the sacral cord results in
hypertonic/hyperreflexive bladder
Lesion above T6 prevents
spinal cord from receiving signals from brain to inhibit sympathetic activity - noxious stimuli can cause autonomic dysreflexia
Interfere with descending control of heart rate, blood pressure and respiration; affect cranial nerve nuclei
ANS correlation with brainstem injury
Damage to hypothalamus disrupts homeostasis with metabolic and behavioral dysfunctions
ANS correlation with Cerebral injury
