Unit 9 - The Parasympathetic Division and Compensatory Mechanisms in the ANS

Question 1

Ganglia of the Parasympathetics NS

Answer 1

Tenth Cranial Nerves (Vagus - most important)

• originate in the medulla oblongata
• extend from brain to lower tip of spinal cord

Question 2

Parasympathetic Stimulation

Answer 2

Sympathetic: prepares body for danger
Parasympathetic: reverses these changes when danger is over (do no require immediate action)

Question 3

SLUDDSA

Answer 3

Parasympathetic NS Functions:
Salivation
Lacrimation
Urination
Digestion
Defecations
Sexual Arousal

Question 4

ACh has two types of Effects

Answer 4

Nicotinic: (ACh + Nicotine) = (nAChRs)
- all autonomic ganglia
- sympathetic and parasympathetic preganglionic fibres
Muscarinic (mAChrs) – mushrooms
- expressed in postganglionic parasympathetic terminal of exocrine glands and smooth and cardiac muscles

Question 5

What (nAChRs) and (mAChRs) have in common

Answer 5

• Activated by same specific neurotransmitter: ACh
• Ionotropic receptor activated opens a channel that allows Na, K and Cl to flow
• mAChRs activated, intracellular signals and opening of Na, K and Cl channels

Question 6

Metabotropic Receptors - Opening Channels

Answer 6

• G - a - subunit deactivates AC
• While B - y subunit=it activates K - channels = hyperpolarize the membrane ( causes decrease in cardiac activity)
• take longer to open ( not involved with quick responses)
• longer lasting effect than nAChr

Question 7

Cholinergic Stimulation of the mAChR

Answer 7

M1: expressed in neural system
M3: expressed in organs and tissues

Question 8

Cholinergic Inhibition of the mAChR

Answer 8

M2: expressed in the heart

- Bring the heart rate back to normal after actions of sympathetic nervous system