The circulatory system<\/em><\/strong> transports fuel, materials and oxygen from the respiratory and digestive systems to the body tissues, and carries waste material and carbon dioxide from the tissues for elimination.<\/p>\n
The respiratory and circulatory systems work together and are closely interlinked. Together these systems are referred to as the cardiovascular system<\/em><\/strong>.<\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row use_custom_gutter=”on” gutter_width=”1″ make_equal=”on” _builder_version=”4.22.0″ _module_preset=”default” background_size=”initial” background_position=”top_left” background_repeat=”repeat” max_width=”100%” module_alignment=”center” custom_padding=”50px|0px|0px|0px|false|false” use_custom_width=”on” width_unit=”off” custom_width_percent=”100%” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_column type=”4_4″ _builder_version=”4.22.0″ _module_preset=”default” custom_padding=”||||false|false” custom_padding_tablet=”” custom_padding_phone=”|5%||5%” custom_padding_last_edited=”on|phone” global_colors_info=”{}” custom_padding__hover=”|||” theme_builder_area=”post_content”][et_pb_text _builder_version=”4.22.0″ _module_preset=”270bbe4d-d73b-4336-a484-4ade375d122e” global_colors_info=”{}” theme_builder_area=”post_content”]<\/p>\n Blood circulates around your body to fuel the body with oxygen. The blood is made mainly of plasma, a clear fluidthat carries the blood cells. All this is pumped around by the heart. Blood vessels carrying blood away from the heart are called arteries<\/em><\/strong>. <\/span><\/p>\n [\/et_pb_text][et_pb_text _builder_version=”4.22.0″ _module_preset=”270bbe4d-d73b-4336-a484-4ade375d122e” global_colors_info=”{}” theme_builder_area=”post_content”]<\/p>\n The body reacts to immersion in cold water by slowing the heart rate down, (bradycardia<\/strong><\/em>). The reaction is called the Mammalian Diving Reflex<\/strong><\/em>. This is why near-drowning victims in very cold water can sometimes be revived, even after having been submerged for a long time.<\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row use_custom_gutter=”on” gutter_width=”1″ make_equal=”on” _builder_version=”4.22.0″ _module_preset=”default” background_size=”initial” background_position=”top_left” background_repeat=”repeat” max_width=”100%” module_alignment=”center” custom_padding=”0px||||false|false” locked=”off” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_column type=”4_4″ _builder_version=”4.22.0″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_text _builder_version=”4.22.0″ _module_preset=”8b1f8231-1210-4c64-bae4-d177be5c655c” background_color=”#FFFFFF” custom_padding=”5%|5%|5%|5%|true|false” locked=”off” global_colors_info=”{}” theme_builder_area=”post_content”]<\/p>\n | <\/span> Background story: The last breath (2019)<\/strong><\/span><\/p>\n <\/p>\n <\/p>\n The Last Breath (2019) is a gripping documentary telling the true story of commercial diver Chris Lemons. While working on the seabed of the North Sea, an accident leaves him stranded 100 meters below the surface with only five minutes of breathing gas in his tank. His lifeline to the diving bell is severed, and his diving team faces an impossible rescue mission.<\/p>\n <spoiler alert><\/em><\/p>\n It took the team around 30 minutes to locate Chris and pull him back onboard the diving bell. Against all odds, Chris was revived even after being out of Oxygen for a long time. It is likely that the cold water and the high oxygen content in his gas mix helped him survive.<\/p>\n [\/et_pb_text][et_pb_text _builder_version=”4.22.0″ _module_preset=”270bbe4d-d73b-4336-a484-4ade375d122e” global_colors_info=”{}” theme_builder_area=”post_content”]<\/p>\n The carotid sinus receptors<\/em><\/strong> monitor the pressure of arterial blood reaching the brain. Breathing contaminated air can cause carbon monoxide poisoning<\/strong><\/em>. Carbon monoxide bonds with the haemoglobin 200 times more easy than oxygen does. When this happens, haemoglobin can carry less oxygen around the body and the diver can black out due to lack of oxygen (hypoxia)<\/strong><\/em>. Signs and symptoms include headache, confusion, narrow vision, bright red lips and fingernail beds.<\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row column_structure=”1_3,2_3″ make_equal=”on” _builder_version=”4.22.0″ _module_preset=”default” background_size=”initial” background_position=”top_left” background_repeat=”repeat” max_width=”100%” module_alignment=”center” custom_padding=”5%||||false|false” use_custom_width=”on” width_unit=”off” custom_width_percent=”100%” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_column type=”1_3″ _builder_version=”4.16″ _module_preset=”default” custom_padding=”|||0px” custom_padding_tablet=”” custom_padding_phone=”||0px|0px” custom_padding_last_edited=”on|phone” global_colors_info=”{}” custom_padding__hover=”|||” theme_builder_area=”post_content”][et_pb_image src=”https:\/\/courses.asiascubainstructors.com\/wp-content\/uploads\/2024\/09\/PADI-IDC-theory-lungs.jpg” force_fullwidth=”on” align_tablet=”center” align_phone=”” align_last_edited=”on|desktop” _builder_version=”4.16″ _module_preset=”default” animation_style=”fade” animation_delay=”500ms” global_colors_info=”{}” theme_builder_area=”post_content”] [\/et_pb_image][\/et_pb_column][et_pb_column type=”2_3″ _builder_version=”4.22.0″ _module_preset=”default” custom_padding=”||||false|false” custom_padding_tablet=”” custom_padding_phone=”10%||0%|” custom_padding_last_edited=”on|phone” global_colors_info=”{}” custom_padding__hover=”|||” theme_builder_area=”post_content”][et_pb_text _builder_version=”4.22.0″ _module_preset=”270bbe4d-d73b-4336-a484-4ade375d122e” global_colors_info=”{}” theme_builder_area=”post_content”]<\/p>\n The air enters\u00a0through the mouth and nose and enters the trachea<\/strong><\/em> (windpipe) The trachea branches into the right and left bronchi<\/strong><\/em>, which lead into the lungs.<\/p>\n The lungs are often compared with balloons but are actually more like sponges.<\/p>\n Inside the lungs, the left and right bronchi split into smaller and smaller bronchioles<\/strong><\/em> until reaching the alveoli<\/strong><\/em>; small sacs surrounded by the pulmonary capillaries. This is where the gas exchange takes place.<\/p>\n [\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row _builder_version=”4.22.0″ _module_preset=”default” locked=”off” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_column type=”4_4″ _builder_version=”4.22.0″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_text _builder_version=”4.22.0″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”]<\/p>\nCirculatory system<\/h3>\n
Red blood cells<\/strong><\/em> give the blood a red color.\u00a0The red blood cells contain haemoglobin<\/em><\/strong> which bonds with oxygen so that it can be transported.
White blood cells<\/strong><\/em> fight off infection and platelets<\/em><\/strong> help the blood to clot in case of injury.<\/p>\n
Blood vessels carrying blood back to the heart are called veins<\/strong><\/em>.
In between the arteries and veins are small blood vessels where the tissues take on oxygen and release CO2 – these are called capillaries<\/em><\/strong>.<\/p>\n
<\/strong><\/span><\/p>\n![\"last](\"https:\/\/courses.asiascubainstructors.com\/wp-content\/uploads\/2024\/09\/last-breath-253x300.jpg\")
<\/p>\n
Receptors will interpret the pressure from an excessively tight hood, wet suit neck seal or dry suit neck seal, as high blood pressure. This will cause the heart to slow down (bradycardia<\/strong><\/em>), reducing blood flow to the brain. The diver can feel light headed and if this continues it can lead to unconsciousness. This is called the Carotid Sinus Reflex<\/strong><\/em>.<\/p>\nRespiratory system<\/h3>\n