EXAM 2 - Nervouse System PNS

Question 1

3 x Main ANATOMY differences between Sympathetic and Parasympathetic

Answer 1

1. SITES OF ORIGIN
   PS: Fibres are craniosacral –> Originate in brain & sacral spinal cord.
   S: Thoracolumbar –> originate in thoracic and lumbar regions of spinal cord
2. LENGTH IN FIBRES
   PS: Long preganglionic & short postganglionic fibres
   S: Short Preganglionic & Long postganglionic (short at start cause ganglions are close to spine, where the fibres originate from)
3. LOCATION OF GANGLIA
   PS: Ganglia located in/near their visceral effector organ.
   S: Ganglia lie close to spinal cord.

Question 2

Major neurotransmitters of ANS

Answer 2

acetylcholine (ACh) and norepinephrine (NE)

Question 3

Which systems use which neurotransmitter

Answer 3

Somatic (SNS) and ANS: Parasympathetic = ACH
(Preganglionic & postganglionic axons)

Sympathetic (Preganglionic axons) = ACH
Sympathetic (Most postganglionic) = NE

Question 4

Main FUNCTIONAL differences of Parasympathetic and Sympathetic

Answer 4

SYMPATHETIC
- ‘Fight or flight’ response
- mobilizes body during activity or extreme situations

PARASYMPATHETIC
- ‘Rest & digest’
- Performs maintenance body activities
- Conserves body energy

Question 5

DIFFERENCES between SNS and ANS

Answer 5

1. EFFECTOR ORGAN
   - SNS: skeletal muscles
   - ANS: Smooth muscle, glands, cardiac muscle
2. CONTROL
   - SNS: Voluntary control of skeletal muscles
   - ANS: Involuntary control of visceral organs
3. NEUROTRANSMITTER:
   - SNS: All somatic motor neurons release Acetycholine (ACh)
   - ANS: Preganglionic fibres release ACh
   Postganglionic fibres release ACh (parasympathetic) OR NE (Sympathetic)
4. NEUROTRANSMITTER EFFECT:
   - SNS: Always excitatory
   - ANS: Might be excitatory OR inhibitory depending on receptor type of effector organ

Question 6

DIFFERENCES between SNS and ANS

Answer 6

1. EFFECTOR ORGAN
   - SNS: skeletal muscles
   - ANS: Smooth muscle, glands, cardiac muscle
2. CONTROL
   - SNS: Voluntary control of skeletal muscles
   - ANS: Involuntary control of visceral organs
3. NEUROTRANSMITTER:
   - SNS: All somatic motor neurons release Acetycholine (ACh)
   - ANS: Preganglionic fibres release ACh
   Postganglionic fibres release ACh (parasympathetic) OR NE (Sympathetic)
4. NEUROTRANSMITTER EFFECT:
   - SNS: Always excitatory
   - ANS: Might be excitatory OR inhibitory depending on receptor type of effector organ
5. NEURON STRUCTURE:
   - SNS: single neuron from CNS to effector organs; heavily myelinated
   • ANS: two-chain neuron from CNS to effector organs: first is lightly myelinated, second is nonmyelinated

Question 7

Reflex Arc - Name 5 steps

Answer 7

1. Receptor
2. Sensory neuron
3. Integration Centre
4. Motor neuron
5. Effector

Question 8

Reflex Arc - Describe each Step

Answer 8

1. Receptor - Site of stimulus action
2. Sensory neuron - Transmits afferent impulses to CNS
3. Integration Centre - Either Monosynaptic or polysynaptic region within CNS
4. Motor neuron - Conducts efferent signal from CNS to effector organs
5. Effector - Muscle fibre / gland cell that responds to efferent impulses by contracting or secreting

Question 9

Cranial Nerves 1 - 4

Answer 9

1 Olfactory (detects odor)
2 Optic (vision)
3 Oculomotor (eye movement)
4 Trochlear (eye movement)

Question 10

Cranial Nerves 5-8

Answer 10

5 Trigeminal (facial sensation; motor control of chewing muscles)
6 Abducens (eye movement)
7 Facial (facial expressions)
8 Vestibulocochlear (hearing & balance)

Question 11

Cranial Nerves 9-12

Answer 11

9 Glossopharyngeal (controls tongue & pharynx; taste)
10 Vagus (controls several visceral organs
11 Accessory (relationship with vagus nerve)
12 Hypoglossal (tongue musles)