Movement of gasses and control of breathing

Overview of content How and where gas is exchanged – External Respiration – Gas transport – Internal Respiration How we consciously and subconsciously control breathing.

External respiration The change of gas between the alveoli in the lungs and the blood. – Blood flowing in the capillaries around the alveoli is low in oxygen and high in carbon dioxide – High oxygen and low carbon dioxide inside the alveoli – Gas follows the rules of diffusion (high concentration to low concentration

Gas transport in blood Most oxygen is carried inside RBC’s attached to hemoglobin molecules – A little oxygen is carried as a dissolved gas in plasma. Most carbon dioxide is carried as a bicarbonate ion in the plasma

Internal respiration The gas exchange that occurs between the blood and tissues of the body. Opposite of what we see in the lungs – High concentration of oxygen and low concentration of carbon dioxide in the blood – Low concentration of oxygen and high concentration of carbon dioxide in the cells – Gasses diffuse from areas of high concentration to areas with low concentration

Carbon monoxide poisoning Carbon monoxide poisoning occurs when people are in areas with high concentrations of carbon monoxide gas – The gas binds to hemoglobin in the same place that oxygen would – Prevents oxygen from binding to hemoglobin Leading cause of death from fires Can cause long term brain damadge

Carbon monoxide poisoning

Control of respiration Normal (non conscious) breathing is controlled by our Pons and Medulla oblongata. – Send signals to the intercostal muscles and the diaphragm to contract. – Normal breathing rate is around breaths/min. We breath more vigorously and deeply during exercise but rate of breathing does not change significantly (until sever exhaustion sets in)

Factors influencing breathing Physical factors can affect the rate of breathing – Talking, coughing, exercise can affect depth and rate of breathing Conscious control – We can control our breathing to a point You have all controlled your breath when singing Try to hold your breath indefinitely and your body eventually forces you to breath.

Factors influencing breathing cont. Chemical factors – These play largest roll in breathing – Changes in Oxygen and Carbon Dioxide levels in the blood are sensed in bodies. – As these levels go up or down our bodies change the way we breath to increase or decrease levels in blood.