Integration of locomotion and ventilation

Question 1

How do ancestral tetrapods move and breath?

Answer 1

Move by lateral body undulation couples with limb motion = sprawling locomotion
Breathing is powered by hypaxial muscles

Question 2

Give an example of an animal that uses the sprawling motion?

Answer 2

Lizards use a sprawling gait and bend their backs from side to side as they run

Question 3

At what point on the phylogenic tree did costal (rib cage) breathing develop?

Answer 3

Between amphibians and mammals

Question 4

What are some adaptations and constraints developed by animals in relation to locomotion and ventilation?

Answer 4

1. Paired fins
2. Lateral body undulation
3. Two-stroke buccal pump

Question 5

Can lizards run and breathe at the same time?

Answer 5

No = functional constraint (trade-off)

Question 6

What are features of early tetrapod locomotion?

Answer 6

Sprawling limb posture
Lateral bending of trunk during locomotion
Relatively massive distal limbs
Same muscles used for ventilation and trunk stabilisation
- limited endurance and aerobic scope
- short bursts of locomotion

Question 7

What things were developed between mammals and birds on the phylogenic tree?

Answer 7

Upright motion
Parasagittal limb movement, speed, aerobic scope and endurance
Diaphragm breathing

Question 8

What features do animals have to allow them to avoid constraints on simultaneous locomotion and ventilation?

Answer 8

Upright limb posture
Sagittal bending of the trunk
Lateral stability of trunk - allows body wall muscles to ventilate
Diaphragm muscle (mammals) - allows breathing without body wall muscles
Bipedal locomotion (birds and humans) - reduces locomotor forces on body wall

Question 9

What is the locomotor-ventilatory coupling?

Answer 9

Integrated function to achieve both effectively

Question 10

What is the function of locomotor-ventilatory coupling?

Answer 10

Gives evidence for a number of hypothesis:

• help do the work of breathing via locomotor forces
• avoid conflict in the muscles that must function in both activities
• mixing of air to improve gas diffusion in the lungs
• ‘pneumatic stabilisation’ - using the lungs as an air bag to help stabilise the body during locomotion
• an accident of neural feedback coupling

Question 11

Is coupling in humans simply a side effect of neural control?

Answer 11

General pattern for locomotion (brain + spinal cord)
↓ ↓
Central respiratory controllers ← ↑ ↓
↑ moving limb proprioceptors
Chest wall receptors and air
sac receptors
In a sense yes

Question 12

Is ventilation and locomotion in turtles independant or dependant?

Answer 12

Independant

Question 13

Describe the ventilatory-locomotor integration in humans?

Answer 13

Bipedal, upright (impact loads minimally influence breathing)
Low breathing frequency ~ 2:1 (strides:breath)
Variable (flexible) coordination
- visceral piston model