9-26b ANS Neural Control of CVP Function Flashcards
Where does the Central Autonomic Network (Hypothalamus) receive afferent information from?
Cingulate cortex and amygdala (Important centers within the limbic sys. (emotions))
Basal forebrain (Helps with general arousal)
Midbrain (Groups of n. within brain stem that provide info to hypothalamus)
Nucleus of tractus solitaries (Blood ph/pressure)
Hippocampus (Helps process memories)
Retina
Where is the afferent information processed in the brain?
Hypothalamic nuclei
What does the hypothalamus do?
regulates physiological, emotional limbic, memory, conscious control systems, and decision making systems to regulate action
What is the efferent autonomic control to the heart?
T1-T4 PVG innervate the heart at the SA and AV nodes to increase contractility and HR
What is the efferent autonomic control to the heart for the SNS? What is the effect?
T1-T4 PVG innervate the heart at the SA and AV nodes to increase contractility (positive inotropy)
HR (positive chronotropy)
What is the efferent autonomic control to the heart for the PNS? What are the effects?
Dorsal motor nucleus of the vagus > SA and AV nodes
decreases HR (negative chronotropy)
decreases contractility
decreases SV
What accelerates the efferent SNS control of the hearts?
cardiac accelerator center
What accelerates the efferent PNS control of the heart?
cardiac inhibitory center
Does the peripheral vasculature have PNS innervation?
no
How does the ANS control the peripheral vasculature?
sympathetic efferent n. that secrete NE and E (catecholamines) that cause vasoconstriction
How does the ANS control BP of the peripheral vasculature?
enhanced: vasoconstriction elevates BP
suppressed: vasodilation and lowers BP
What are the two afferent components of cardiac reflexes?
sensory receptors:
Baroreceptors (pressure changes)
Chemoreceptors (PCO2, PO2)
Where are baroreceptors of the heart located?
aortic arch X afferent
carotid bodies IX afferent
How do baroreceptors monitor BP?
Firing rate changes when BP falls or increases directly; sensors stimulate the central autonomic network
Generally describe the control of cardiac function
As BP rises, baroreceptors increase firing rate and info goes from the aoritic arch and carotid bodies via IX and X nerves to cardiac accelerator and inhibitory centers > go down the spinal cord via vagus efferent n. to change sympathetic and parasympathetic outflow
How does the ANS react to a decreased BP?
baroreceptors reduce firing to cardiac inhibitory center, which reduces parasympathetic activity and contractility
baroreceptos increase firing to cardiac accelerator center and excites the sympathetic system. This results in increased contractility and increases TPR via vasoconstriction
How does the ANS react to an elevated BP?
baroreceptors reduce firing to the cardiac accelerator center to lower contractility and allow for vasodilation
baroreceptors increase firing to the cardiac inhibitory center and increase parasympathetic activity to reduce contractility
Why is it necessary for the body to control body temperature?
electrochemical processes require an optimum temperature at which they can operate efficiently
What does the hypothalamus act as in relation to body temp? How does it control it?
a thermostat
controls how heat can be dissipated or conserved
What sense a change in body temp? Where do they send signal to? What happens next?
thermoreceptors > hypothalamus (compares against set point of 98.6) > PNS and SNS input to sweat glands and blood vessels to change how heat is dissipated/concerved
What do warm sensitive neurons in the hypothalamus lead to?
n. lead to SNS reduction and vasodilation > PNS activates sweat glands and dissipation of heat and dissipates heat
What do cold sensitive neurons in the hypothalamus lead to?
n. lead to SNS activation > vasoconstriction (minimizes overall heat loss from skin surfaces)
shivering is phenomenon where skeletal m. produce heat and increase body temp.
What is the goal of glucose and energy homeostasis?
What systems work to find homeostasis?
balance food intake and energy expenditure
hormonal and neural sys.
What do glycogenolysis and gluconeogenesis do?
make glucose
glycogenolysis (break down of glycogen)
gluconeogenesis (break down of aa)
