Exam 6: homeostasis

Question 1

What is the key regulator of homeostatic systems?

Answer 1

Hypothalamus

Question 2

What is the mechanism of heat conservation?

Answer 2

vasoconstriction

Question 3

What do local temperature receptors release to avoid too high of a temp? What does it do?

Answer 3

Nitric Oxide; vasodilator

Question 4

What signals do core temp sensors send to the CNS to decrease heat?

Answer 4

Activates sympathetic nerve outflow (both andregnergic and cholinergic) to increase skin blood flow and increase sweating

Question 5

What are the pyrogens that stimulate the hypothalmus PGE2?

Answer 5

IL-1, IL-6, TNF-alpha

Question 6

What does the hypothalamus secrete in response to pyrogens?

Answer 6

PGE2

Question 7

What is the equation of blood pressure?

Answer 7

BP= (heart rate) x (stroke volume) x (total peripheral resistance)

Question 8

Describe what sympathetic nerves do with Beta and Alpha receptors

Answer 8

Beta1 receptors to stimulate heart rate and increase stroke volume. Alpha1 receptors to increase resistance

Question 9

Is the vagus nerve sympathetic or parasympathetic innervation?

Answer 9

Parasympathetic

Question 10

What does vagus nerve innervation to the heart do? What NT and receptor does it stimulate?

Answer 10

Slows the heart rate. Secretes acetylcholine to interact with muscarinic receptors

Question 11

Describe the baroreceptor pathway in the carotid arteries and aortic arch.

Answer 11

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

Question 12

Describe the sympathetic innervation of the heart

Answer 12

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

Question 13

What are the 3 phases of ventilation?

Answer 13

Inspiration, post-inspiration, expiration

Question 14

Where is the pacemaker of breathing located?

Answer 14

Pre-boetzinger area of ventrolateral medulla

Question 15

What does the pre-boetzinger area of ventrolateral medulla stimulate to set the pace of breathing?

Answer 15

C3-C5 (via phrenic nerve)

Question 16

What are the inputs to the pre-boetzinger area?

Answer 16

Parafacial respiratory center senses CO2 (mostly hydrogen atoms), exciting Pre-Boetzinger area. Parafacial resp. center also directly excites muscles involved in active expiration (abdominals)

Question 17

What does lack of carbon dioxide sensors lead to?

Answer 17

Hypoventilation while sleeping

Question 18

T/F: urination is controlled by both voluntary and involuntary muscles?

Answer 18

True

Question 19

What NT/receptor is on the external sphincter of the bladder?

Answer 19

Acetylcholine/nicotinic receptors on the voluntary skeletal muscles

Question 20

What NT/Receptor is on the internal sphincter and detrusor (wall) of the bladder?

Answer 20

Acetylcholine/muscarinic receptors of the parasympathetic nervous system

Question 21

Where do bladder filling sensors send afferent info?

Answer 21

Medial prefrontal cortex (that normally suppresses voiding) which will suppress inhibition of voiding

Question 22

What branch of the autonomic nervous system serves to contract the urinary bladder?

Answer 22

Parasympathetic nerves

Question 23

How would you treat someone who is incontinent?

Answer 23

Muscarinic receptor antagonists (works against parasympathetic nervous system)