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Physical and Chemical Properties of Pumping Blood
Avian hearts are generally larger than mammalian hearts when compared to body mass. This adaptation allows more blood to be pumped to meet the high metabolic need associated with flight. Birds, like the flamingo, have a very efficient system for diffusing oxygen into the blood; birds have a ten times greater surface area to gas exchange volume than mammals. As a result, birds have more blood in there capillaries per unit of volume of lung than a mammal. The Flamingo’s (Phoenicopterus Ruber) four chambered heart is myogenic meaning that all the muscle cells and fibers have the ability to contract rhythmically. The rhythm of contraction is controlled by the pace maker cells which have a lower threshold for depolarization. The wave of electrical depolarization initiated here is what physically starts the heart’s contractions and begins pumping blood. Pumping blood creates variations in blood pressure and as a result, creates different thicknesses of blood vessels. The Law of LaPlace can be used to explain why arteries are relatively thick and veins are thin.

Flamingo Blood Composition
It was widely thought that avian blood had special properties which attributed to a very efficient extraction and transportation of oxygen in comparison to mammalian blood. This of course is not true; there is no real difference in the efficiency of the blood, and both mammals and birds use a hemoglobin molecule as the primary oxygen carrier with little to no difference in oxygen carrying capacity. Captivity and age have been seen to have an effect on the blood composition of the American flamingo (Phoenicopterus Ruber). A decrease in white blood cell numbers was predominate with age in both captive and free living flamingos, but captive flamingos showed a higher white blood cell count than free living flamingos. One exception occurs in free living flamingos with regards to white blood cell count. The number of eosinophils in free living birds are higher because these cells are the ones that fight off parasites which  a free living bird may have more contact with than a captive one. Captive birds showed higher hematocrit and red blood cell numbers than the free living flamingos, and a blood hemoglobin increase was seen with age. An increase in hemoglobin would correspond with an adults increase in metabolic needs. A smaller mean cellular volume recorded in free living flamingos coupled with similar mean hemoglobin content between captive and free living flamingos could show different oxygen diffusion characteristics between these two groups. Plasma chemistry remains relatively stable with age but lower values of protein content, uric acid, cholesterol, triglycerides, and phospholipids were seen in free living flamingos. This trend can be attributed to shortages and variances in food intake in free living flamingos.

Specialized Osmoregulatory Cells and Transport Mechanisms
The salt gland used by the American Flamingo (Phoencopterus ruber) has two segments, a medial and lateral segment. These segments are tube shaped glands that consist of two cell types. The first is the cuboidal – peripheral cells which are small, triangular shaped cells which have only a few mitochondria. The second specialized cells are the principal cells which are found down the length of the secretory tubules, and are rich in mitochondria. These cells are similar to the mitochondria rich cells found in teleost fish.

These cells within the salt gland employ several types or transport mechanisms that respond to osmoregulatory loads. Sodium-Potassium ATPase works with a Sodium-Chloride co-transporter (also known as the NKCC), and a basal potassium channel to secrete salt (NaCl) into secretory tubes. The ATPase uses energy from ATP to pump three sodium ions out of the cell and two potassium ions into the cell. The potassium channel allows potassium ions to diffuse out of the cell. The cotransporter pumps one sodium, potassium and two chloride ions in to the cell. The chloride ion diffuses through the apical membrane into the secretory tube and the sodium follows via a paracellular route. This is what forms the hyperosmotic solution within the salt glands.

Avian erythrocytes (red blood cells) have been shown to contain approximately ten times the amount of taurine (an amino acid) than mammal erythrocytes. Taurine has a fairly large list of physiological functions; but in birds, it can have an important influence on osmoregulation. Taurine helps the movement of ions in erythrocytes by altering the permeability of the membrane and regulating osmotic pressure within the cell. The regulation of osmotic pressure is achieved by the influx or efflux of taurine relative to changes in the osmolarity of the blood. In a hypotonic environment cells, will swell and eventually shrink; this shrinkage is due to efflux of Taurine. This process also works in the opposite way in hypertonic environments. In hypertonic environments, cells tend to shrink and then enlarge; this enlargement is due to an influx in taurine, affectively changing the osmotic pressure. This adaptation allows the flamingo to regulate between differences in salinity.

One hypothesis for the bird’s adaptation to respiratory alkalosis is tracheal coiling. Tracheal coiling is an overly long extension of the trachea and can often wrap around the bird’s body. Prange et al discussed that when faced with a heat load, birds often use thermal panting and this adaptation of tracheal coiling allows ventilation of non-exchange surfaces which can enable the bird to avoid respiratory alkalosis. The flamingo uses a “flushout” pattern of ventilation where deeper breaths are essentially mixed in with shallow panting to flush out carbon dioxide and avoid alkalosis. The increased length of the trachea provides a greater ability for respiratory evaporation and cooling off without hyperventilation.