Module 1C: Neuroanatomy Of The Cardiopulmonary System

Question 1

What are the sympathetic functions?

Answer 1

• Reactions to stress
• Increased heart function
• Decreased digestive function
• Pupillary dilation
• Vasodilation in vessels of skeletal muscle
• Vasoconstriction in other vessels (mainly for redirection of blood to areas of need, or to manage peripheral resistance)
• Allows bladder filling, ejaculation

Question 2

What are the parasympathetic functions?

Answer 2

-Recovery of rest, vegetative functions
-Decreased heart function
- Increased digestion (increased peristalsis, glandular secretion, opening of sphincters)
- Pupillary constriction
- Specific vasodilation in salivary glands, GI vessels, and erectile tissues, bowel and bladder emptying

Question 3

Where are the preganglionic is origin of the sympathetic innervation of the heart?

Answer 3

3 cervical: Superior, Middle, Inferior, T2-T5 IML

Question 4

What is the preganglionic path of the sympathetic innervation of the heart?

Answer 4

Ventral root —> white ramus —> sympathetic chain (ascending via interganglionic branches to superior, middle, and inferior cervical chain ganglia, and T2, 3, 4, and 5 chain ganglia; synapse on postganglionic neurons there.

Question 5

What is the postganglionic path of the sympathetic innervation of the heart?

Answer 5

From the seven cardiopulmonary nerves (from the above named ggl) to and through the cardiopulmonary ganglion —> mainly the AV node, Purkinje fibers of the ventricles, and the internodal branches (between the SA and AV nodes.

Question 6

Where are the preganglionic is origin of the parasympathetic innervation of the heart?

Answer 6

Nucleus Ambiguus, open medulla of the
brainstem

Question 7

What is the preganglionic path of the parasympathetic innervation of the heart?

Answer 7

Exiting the jugular foramen of the skull as
the vagus nerve (CN-X) passing inferiorly through the carotid sheath, and the thoracic outlet, through the superior mediastinum to the cardiac ganglia (note that the cardiac and pulmonary ganglia are very near to each other and often are
discussed as the same group of ganglia). Here, the preggl parasympathetic axons synapse of the postggl cells.

Question 8

What is the postganglionic path of the parasympathetic innervation of the heart?

Answer 8

Leaving the cardiac ggl, which are very near
to the heart, these project mainly the SA Node.

Question 9

Where is the origin of high threshold GVA innervation of the heart? What is the path? Where is the cell body and where does it synapse?

Answer 9

Tissue damage
Origin: With the heart
Path: Following the sympathetic path
Cell body: Dorsal root ganglion
Synapse: Spinal cord grey matter at or near IML

Question 10

Where is the origin of low threshold GVA innervation of the heart? What is the path? Where is the cell body and where does it synapse?

Answer 10

Distinction/Stretch
Origin: Heart
Path: Follows the parasympathetic
Cell body: Nodose ganglion of X
Synapse: Medullary gray (nucleus solitarius)

Question 11

What do all preganglionic GVE (both sympathetic and parasympathetic) axon terminals release in the heart? Where do they bind? What do they result in?

Answer 11

• Release acetylcholine
• Bind nicotinic cholinergic receptors on the postganglionic GVE dendrites
• Resulting in fEPSP.

Question 12

What do sympathetic GVE postganglionic axon terminals release in the heart? Where do they bind?

Answer 12

All release norepinephrine (NE) which bind β1
receptors,

Question 13

Where are Beta-1 receptors mainly found in the heart?

Answer 13

Modified cardiac muscles of the AV Node and those cells in the cardiac skeleton called Purkinje cells.

Question 14

What are the actions of beta-1 receptors in the heart?

Answer 14

• increased heart rate (positive chronotropic activity)
• increased strength of contraction (positive inotropic activity)
• increased conduction velocity between the SA and AV nodes (positive dromotropic
  activity)

Question 15

What do parasympathetic GVE postganglionic axon terminals release in the heart? Where do they bind?

Answer 15

Release acetylcholine (ACh)
Bind M2 receptors

Question 16

Where are M2 receptors mainly found in the heart?

Answer 16

Modified cardiac muscles of the SA Node

Question 17

What are the actions of M2 receptors in the heart?

Answer 17

• decreased heart rate (negative chronotropic activity)
• decreased strength of contraction (negative inotropic activity)
• decreased conduction velocity between the SA and AV nodes (negative dromotropic activity)

Question 18

What happens after the M2 receptors bind ACh and via a G-protein mechanism in the heart?

Answer 18

Outflow of K+ = sIPSP

Question 19

What kind of antagonist are influence by M2 receptors and B1 receptors in the heart?

Answer 19

atropine for the M2 receptors
propranolol for B-1 receptors.

Question 20

What is the preganglionic origin of the sympathetic input to innervation of the vasculature in the heart?

Answer 20

All level of the intermediolateral nucleus from
T1-L2,3

Question 21

What is the preganglionic path of the sympathetic input to innervation of the vasculature in the heart?

Answer 21

Ventral root —> White Ramus —> Sympathetic
Chain Ganglia (all levels).

Question 22

What is the postganglionic path of the sympathetic input to innervation of the vasculature in the heart?

Answer 22

leaving the sympathetic chain via the gray rami
to VPR and DPR, splanchnic nerves, and cardiopulmonary nerves, the postganglionic axons are then distributed to all areas of the body wall, limbs, and organs.

Question 23

How does the abdominopelvic system receive its sympathetic input?

Answer 23

the splanchnic nerves and visceral branches that follow the vascular pattern of the abdominopelvic viscera

Question 24

Where do arterioles and arteries receive sympathetic input?

Answer 24

either via peripheral nerves or by the endocrine sympathetic system homologue (the adrenal medulla)

Question 25

What are the sympathetic receptors? What are their functions in the heart?

Answer 25

Alpha-1 Receptors: +, second messenger system-driven; widespread: most vessels, sphincteric smooth muscle (GI and Urinary), radial muscle in the iris for pupillary dilation, excitatory action on the immune system (dose dependent), and others. Beta-1 Receptors: +, second messenger system driven; mainly the heart. Beta-2 Receptors: -, second messenger driven; wherever the Σ system is required to be inhibitory: bronchial smooth muscle, most glands, GI smooth muscle (for peristalsis), and bladder and bowel for allowing filling to occur

Question 26

How does sympathetic cholinergic postganglionic axons work in the heart?

Answer 26

Sympathetic Neurons innervating Vessels perfusing skeletal muscle are largely cholinergic and cause vasodilation by the excitatory receptor M3. M3’s cause vasodilation by increasing the amount of NO (Nitric oxide) available to the vessel. NO is a powerful vasodilator. When skeletal muscles are required to contract continually, they require more O2. this is delivered by increasing the vascular diameter: vasodilation is caused by inhibition of smooth muscle contraction.

Question 27

What are the sympathetic function of the respiratory system?

Answer 27

-In times of stress, the body will need increased amounts of oxygen to fuel the oxidative phosphorylation system and the production of ATP. -At the respiratory tree, the sympathetic function is largely inhibitory: dilation of the bronchial smooth muscle and inhibition of mucous secretions.

Question 28

What are the parasympathetic function of the respiratory system?

Answer 28

- In times of rest, or protection from the elements, the parasympathetic system causes bronchoconstriction and increased mucous secretion - Decreased diameters allow less air (cold air)and particulates in, and the increased mucous aids in humidifying dry air and capturing particulates.

Question 29

What is the preganglionic origin of the sympathetic input to innervation of the bronchi?

Question 30

What is the preganglionic path of the sympathetic input to innervation of the bronchi?

Question 31

What is the postganglionic path of the sympathetic input to innervation of the bronchi?

Question 32

What is the preganglionic origin of the parasympathetic input to innervation of the bronchi?

Question 33

What is the preganglionic path of the sympathetic input to innervation of the bronchi?

Question 34

What is the postganglionic path of the sympathetic input to innervation of the bronchi?

Question 35

Where is the origin of high threshold GVA innervation of the bronchi? What is the path? Where is the cell body and where does it synapse?

Question 36

Where is the origin of low threshold GVA innervation of the bronchi? What is the path? Where is the cell body and where does it synapse?

Question 37

How does muscarinic-3 cholinergic recoptors work in the bronchi?

Answer 37

• M3 receptors bind ACh and via second messenger system, cause smooth muscle contraction and glandular secretion. • This mechanism is complex and involves other muscarinic receptors as well (M1 receptors). Asthma and asthma treatments are important areas of study and research is ongoing.

Question 38

What do sympathetic GVE postganglionic axon terminals release in the bronchi? Where do they bind?

Answer 38

Release norepinephrine (NE) Bind β2 receptors on smooth and glands of the bronchi

Question 39

Where are Beta-2 receptors mainly found in the bronchi?

Answer 39

Many other spots in the body requiring inhibitory sympathetic action

Question 40

What are Beta-2 receptors actions in the bronchi?

Answer 40

- Dilation of the bronchial tree, from primary to respiratory bronchioles - Decreased mucous secretion of the bronchial glands - Beta-2 receptors are found wherever the sympathetic system causes relaxation of smooth muscle or decreased secretion from glands - They cause relaxation of the smooth muscle via second messenger systems using cAMP. - Bottom line: beta-2 receptors bind NE (and EPI) causing smooth muscle relaxation and decreased mucous secretion.

Question 41

What do parasympathetic GVE postganglionic axon terminals release in the bronchi? Where do they bind?

Answer 41

Release acetylcholine (ACh) which bind M3 (muscarinic) receptors M3 receptors are found on smooth muscle and on glandular structures where they cause increased smooth muscle contraction and increased mucous secretion.