3.1.1.1 The respiratory system

Passage order of air (nearly Lobbed The Ball Brilliantly Again)

Nasal cavity, Larynx, Trachea, Bronchi, Bronchioles, Alveoli

Diffusion

Movement of gas from a high concentration to a low concentration

Alveoli adaptations

1 cell thick for a short diffusion path

Dense capillary network for a good blood supply

Larger surface area for a greater uptake of oxygen

Inspiration (at rest)

Diaphragm contracts and ribs move up and out to Increase thoriac volume and decreases pressure

Expiration at rest

Diaphragm relaxes and ribs move down and in. Thoriac volume decreases and pressure increases

Inspiration during exercise

Sternocleidomastoid, Scalene, Pectoralis minor recruited to increase chest expansion and tidal volume

Expiration during exercise

Internal intercostals, rectus abdominals and obliques activated for faster and greater expiration

Minute ventilation

Volume of air breathed in/out per minute TV X F

Process of oxygen diffusion at the alveoli

Po2 high in alveoli and low in blood so oxygen diffuses into blood and binds to haemoglobin

Gaseous exchange at muscles

Po2 high in blood and low in muscles so oxygen diffuses until equilibrium is reached

RCC

Located in medulla oblong at a and stimulates sympathetic and parasympathetic nerves to regulate breathing

Inspiratory centre receptors for regulating pulmonary ventilation

Chemoreceptors, Proprioreceptors , Barroreceptors

Expiratory centre

Stretch detectors

Phrenic nerve

Activates diaphragm and external intercostals for greater inspiration

Intercostal nerve

Activates abdominals and internal intercostals for greater expiration

Training adaptations

Strength of diaphragm/intercostals, Increased lung expansion, Greater diffusion efficiency, Delayed OBLA