Increasing  shifts the curve to the right. Increasing pH and decreasing  shift the curve to the left. Other conditions that lead to a right-shift in the oxyhemoglobin curve are: increased temperature and increased concentration of 2,3-bisphosphoglycerate. These conditions stabilize the deoxygenated form of hemoglobin, facilitating the dissociation of oxygen to the tissues. 

Blood flows along the following course: from the lungs to the left atrium (LA) via the pulmonary vein. From the LA to the left ventricle (LV) through the mitral valve. From the LV to the aorta through the aortic valve. From the aorta to the systemic arteries and systemic tissues (i.e., cerebral, renal, skeletal muscle, etc). It travels from the tissues to the systemic veins and vena cava. From the vena cava to the right atrium (RA). From the RA to the right ventricle via the tricuspid valve. From the RV to the pulmonary artery through the pulmonic valve. From the pulmonary artery to the lungs for oxygenation.

The superficial temporal artery supplies the sides and top of the head, it runs just in front of the ear. The internal carotid artery supplies the brain and eyes. The facial artery supplies the cheeks, lips, and nose. The maxillary artery supplies the mouth and nose. 

The maxillary artery supplies the mouth and nose. The facial artery supplies the cheeks, lips and nose. The internal carotid artery supplies the brain and eyes. The superficial temporal artery supplies the sides and top of the head. 

A single drop of blood typically contains about 250 million red blood cells, and about fifty thousand white blood cells. Platelets are also present in drops of blood, but their numbers can vary from 150,000-450,000.

Portal circulation is found in the gut and liver, it features vessels that carry nutrient rich blood from the gut to the liver for processing. Systemic circulation is between the heart and the tissues of the body. Pulmonary circulation is between the heart and the lungs. There is no special name for circulation of the mouth and head. The other portal circulation is found in the brain - between the hypothalamus and pituitary gland.

The lymphatic system drains excess tissue fluid as well as fights infections. The renal system is responsible for excretion and reabsorption. The circulatory system is responsible for the transportation of oxygen and nutrients throughout the body. 

The confluence of sinuses connects the superior sagittal sinus, straight sinus, and occipital sinus. Blood in the confluence of sinuses drains into the left and right transverse sinuses. From the transverse sinus blood drains to the sigmoid sinus, which ultimately drains into the internal jugular vein. 

Red blood cells, carry oxygen  and carbon dioxide  in the bloodstream. 

Red blood cells are produced in the bone marrow and circulate throughout the body to provide oxygen exchange. They have an average lifespan of 120 days (roughly three months). At the end of their lifespan they are destroyed by specific cells (macrophages) located in the spleen.