pH and gas exchange

Fact of the Day The circulatory system is extremely long If you were to lay out all of the arteries, capillaries and veins in one adult, end-to-end, they would stretch ~100,000 kilometers. Capillaries would make up about 80 percent of this length. Earth circumference = ~40,000 km. That means a person's blood vessels could wrap around the planet approximately 2.5 times!

Vessels to know

pH and Blood Chemoreceptors: monitor chemicals Located in carotid arteries and aorta Low pH stimulates increased breathing rate Hematocrit: ratio of the volume of RBC to total blood volume

Bicarbonate Buffer System Acid base homeostatic mechanism 𝐻 2 𝑂+ 𝐶𝑂 2 ↔ 𝐻 2 𝐶𝑂 3 ↔ 𝐻𝐶𝑂 3 − + 𝐻 + Hydration, dehydration reaction

Gas Exchange – External Respiration Partial pressure: PO2 & PCO2 Blood into the lungs: H+ + HCO3-  H2CO3  H20 + CO2 (increase) Carbonic anhydrase: enzyme present in red blood cells Hemoglobin: respiratory pigment Releases a hydrogen ion  deoxyhemoglobin Hb + O2  HbO2

What is in blood? Connective tissue Blood plasma (~55%) RBCs (erythrocytes), WBCs (leukocytes), & blood platelets (thrombocytes)

Red Blood Cells No nucleus Hemoglobin (Red) Globin protein Heme Transports oxygen

White Blood Cells Larger than RBCs Nucleus Translucent Fight infection Phagocytic or antibodies

Platelets Not complete cells Plugs that seal damaged vessels

Hemoglobin

Gas Exchange – Internal Respiration Diffusion of O2 from high concentration to low O2  plasma  RBCs in lungs  Oxyhemoglobin HbO2  Hb + O2 Diffusion into tissues  cellular respiration

Keeping up with the Joneses

Data from Suzie’s physical

Data from Suzie’s physical