Exam 6: homeostasis Flashcards
What is the key regulator of homeostatic systems?
Hypothalamus
What is the mechanism of heat conservation?
vasoconstriction
What do local temperature receptors release to avoid too high of a temp? What does it do?
Nitric Oxide; vasodilator
What signals do core temp sensors send to the CNS to decrease heat?
Activates sympathetic nerve outflow (both andregnergic and cholinergic) to increase skin blood flow and increase sweating
What are the pyrogens that stimulate the hypothalmus PGE2?
IL-1, IL-6, TNF-alpha
What does the hypothalamus secrete in response to pyrogens?
PGE2
What is the equation of blood pressure?
BP= (heart rate) x (stroke volume) x (total peripheral resistance)
Describe what sympathetic nerves do with Beta and Alpha receptors
Beta1 receptors to stimulate heart rate and increase stroke volume. Alpha1 receptors to increase resistance
Is the vagus nerve sympathetic or parasympathetic innervation?
Parasympathetic
What does vagus nerve innervation to the heart do? What NT and receptor does it stimulate?
Slows the heart rate. Secretes acetylcholine to interact with muscarinic receptors
Describe the baroreceptor pathway in the carotid arteries and aortic arch.
Stretch increases firing rate, impulses carried via CN X and CN IX to medulla, terminating in nucleus of solitary tract. NST suppresses neurons in rostral ventrolateral medulla (sympathoexcitatory area). Decrease in sympathetic innervation decreases heart rate
Describe the sympathetic innervation of the heart
Excitation of sympathetic preganglionic neurons in intermediolateral column of thoracic cord, Sympathetic interact with Beta1 (increase heart rate, stroke volume) and alpha 1 (increase blood pressure) via norepinephrine
What are the 3 phases of ventilation?
Inspiration, post-inspiration, expiration
Where is the pacemaker of breathing located?
Pre-boetzinger area of ventrolateral medulla
What does the pre-boetzinger area of ventrolateral medulla stimulate to set the pace of breathing?
C3-C5 (via phrenic nerve)
What are the inputs to the pre-boetzinger area?
Parafacial respiratory center senses CO2 (mostly hydrogen atoms), exciting Pre-Boetzinger area. Parafacial resp. center also directly excites muscles involved in active expiration (abdominals)
What does lack of carbon dioxide sensors lead to?
Hypoventilation while sleeping
T/F: urination is controlled by both voluntary and involuntary muscles?
True
What NT/receptor is on the external sphincter of the bladder?
Acetylcholine/nicotinic receptors on the voluntary skeletal muscles
What NT/Receptor is on the internal sphincter and detrusor (wall) of the bladder?
Acetylcholine/muscarinic receptors of the parasympathetic nervous system
Where do bladder filling sensors send afferent info?
Medial prefrontal cortex (that normally suppresses voiding) which will suppress inhibition of voiding
What branch of the autonomic nervous system serves to contract the urinary bladder?
Parasympathetic nerves
How would you treat someone who is incontinent?
Muscarinic receptor antagonists (works against parasympathetic nervous system)
