Autonomic Nervous System

Question 1

Vertebral column (Spine)

Answer 1

• Houses and protects spinal cord
• Muscle attachment
• Locomotion
• Series of irregular bones with regional variations
• Regions of the vertebral column • Cervical / thoracic / lumbar / sacral /
caudal or coccygeal
• Vertebral formula (dog) • C7T13L7S3CCvariable

Question 2

Thoracic spine

Answer 2

Corresponds with number of ribs (13 in dog and cat)
• Limited movement in this region (due to articulation with ribs at
costal fovea)
• Protects thoracic viscera
• Provides attachment for thoracic limb • Short vertebral body
• Long dorsal spinous process
• Small transverse process

Question 3

Lumbar Spine

Answer 3

Stouter vertebral bodies
• Forward sloping dorsal spinous
processes
• Long flat transverse processes
Ligaments
1. Supraspinousligament; 2. spinous process;
3. interspinous ligament; 4. arch of vertebra;
5. interarcuate ligament; 6. Intervertebral
foramen;
7. dorsal longitudinal ligament;
8. ventral longitudinal ligament;
9. intervertebral disc

Question 4

Sacral spine

Answer 4

The sacrum is a single bone formed by three fused vertebrae

• The sacrum articulates with the pelvic girdle • Reduced dorsal spinous processes

Question 5

Coccygeal spine

Answer 5

• AKA caudal spine
• Number varies
• Processes are reduced

Question 6

Divisions of the autonomic nervous system

Answer 6

• Sympathetic
• Fight and flight response (4Fs) • Thoracolumbar outflow
• Parasympathetic
• Maintains homeostasis • Relaxed state
• Rest and digest
• Craniosacral outflow

Question 7

Anatomy of the autonomic nervous system

Answer 7

• Motor and sensory component
• Motor component consists of pre and post ganglionic fibres • Dual innervation of organs
• All pre-ganglionic fibres cholinergic, are myelinated (fast)
• Post ganglionic fibres are unmyelinated (slower but efficient) • Parasympathetic are cholinergic
• Sympathetic mostly adrenergic

Question 8

Anatomy of the autonomic nervous system

Sympathetic

Answer 8

• Pre-ganglionic fibres in lateral horn of thoracolumbar spinal cord
• Sympathetic – one pre-ganglionic fibre synapses with 20 post-ganglionic fibres
• Sympathetic ganglia near spine (short neurons for speed of response)
• No cranial nerves contain sympathetic fibres (thoracolumbar outflow only)

Question 9

Anatomy of the autonomic nervous system

Parasympathetic

Answer 9

• Parasympathetic ganglia in or near target (except for those of the head)
• Parasympathetic – one pre-ganglionic fibre synapses with four post-ganglionic fibres
• Cranial nerves containing parasympathetic fibres • Occulomotor
• Facial
• Glossopharyngeal
• Vagus

Question 10

Sympathetic response

Answer 10

Fight or flight
Muscles tense
Increase heart rate
Pupils dilate (let more light in)
Decrease salivation (dry mouth)
Adrenalin released from adrenal glands
Glycogen converted to glucose
Shorter neurons allows a faster response time

Question 11

Parasympathetic response

Answer 11

Maintains homeostasis
Rest and digest
Pupils contract
Increase salivation (for digestion)
Longer neurons respectively leading to slower responses

Question 12

Pharmacological regulation of the autonomic nervous system

Answer 12

• Pharmacology will be covered fully at a later stage of the course
• Here are some common examples of drugs you may have come across
that act on the ANS
Salbutamol– inhibits bronchospasm
Propanolol – slows heart rate, reduces blood pressure