11th Biology Chapter 15

– Blood

Summary: Blood is a special connective tissue composed of plasma and formed elements. Plasma, the fluid matrix, accounts for 55% of blood and contains water, proteins, minerals, and other substances. Formed elements include erythrocytes (RBCs), leukocytes (WBCs), and platelets, each with specific functions such as gas transport, defense mechanisms, and clotting【4:0†source】【4:1†source】.

– Lymph (Tissue Fluid)

Summary: Lymph, a fluid derived from blood, resembles blood but lacks certain proteins and formed elements. It plays a role in maintaining fluid balance in tissues and aids in the immune response【4:1†source】.

– Circulatory Pathways

Summary: The circulatory system in humans consists of a muscular heart, blood vessels, and blood. It operates through two pathways – pulmonary circulation (deoxygenated blood to lungs, oxygenated blood to heart) and systemic circulation (oxygenated blood to body tissues, deoxygenated blood to heart)【4:2†source】.

– Double Circulation

Summary: Double circulation refers to the separation of oxygenated and deoxygenated blood in the heart. Incomplete double circulation (single ventricle) is seen in some animals, while complete double circulation (two separate pathways) exists in birds and mammals, allowing efficient oxygenation and circulation【4:2†source】.

– Regulation of Cardiac Activity

Summary: Cardiac activity in the heart is autoexcitable but can be influenced by neural and hormonal mechanisms. The heart's function is moderated to adjust heart rate and contractility based on the body's needs【4:2†source】.

– Disorders of Circulatory System

Summary: Various disorders can affect the circulatory system, leading to conditions like clotting disorders, excessive blood loss, and heart rhythm abnormalities. Understanding these disorders is crucial for proper diagnosis and treatment【4:2†source】.