Circulatory System

• Circulatory System

  • an organ system responsible for the transportation of oxygen, nutrients, hormones, and waste products throughout the body
• OPEN CIRCULATORY SYSTEM

  • the blood directly diffuses into the cells and body cavities and travels back to the heart via diffusion
  • the resulting blood flow is sluggish
  • most common in insects, mollusks and other invertebrates
• CLOSED CIRCULATORY SYSTEM

  • the blood is enclosed inside the different blood vessels and other parts of the circulatory system at all times
  • there is presence of hemoglobin
  • found in all vertebrates and some invertebrates
• Cardiovascular System

  • Definition: a network of vessels that circulates blood throughout the body
  • Components: blood, blood vessels, heart
  • Functions: oxygen and nutrient delivery, waste removal
• Lymphatic System

  • Definition: a network of vessels that circulates lymph throughout the body
  • Components: lymph, lymphatic vessels, lymphatic tissue
  • Functions: fluid balance, immune response, fat absorption
• THE BLOOD

  It is a special fluid primarily contained within the blood vessels. Blood is primarily produced by a process called hematopoiesis, which occurs in the bone marrow.
• Functions of Blood

  1. Nutrition - nutrients such as glucose and amino acids are carried to cells for energy and metabolism
  2. Excretion - waste products and metabolic byproducts are transported away from tissues to be excreted by organs
  3. Homeostasis - blood contributes to thermoregulation and osmoregulation
  4. Hormonal Transplant - hormones secreted by glands are also transported i to target tissues where they exert their effects
• Main Components of Blood

  1. Erythrocytes (RBCs)
  2. Leukocytes (WBCs)
  3. Thrombocytes (Platelets)
  4. Plasma
• Erythrocytes - Red blood cells

  • contain hemoglobin, primary oxygen transport molecule
• Thrombocytes - Platelets

  • gather at the site of injury and help in the blood clotting process
• Plasma

  • straw-coloured liquid that serves as the medium in which blood cells and various substances are suspended
• Formed Elements of Blood:

  1. Platelet
  2. Erythrocyte
  3. Leukocyte
  4. Monocyte
  5. Basophil
• Formed Elements of Blood

  1. Platelet
  2. Erythrocyte
  3. Leukocyte
  4. Monocyte
  5. Basophil
  6. Lymphocyte
  7. Neutrophil
  8. Eosinophil
• THE BLOOD VESSELS

  • These are tubes or channels that carry blood throughout our body. There are three types of blood vessels—veins, arteries and capillaries. Each one differs in size and structure
• Three types of blood vessels:

  • veins
  • arteries
  • capillaries
• Capillary - assists in the exchange of substances between the blood and tissues
• THE HEART

  It is a muscular organ that pumps to move the blood around the body. It typically consists of multiple chambers organized into two or more compartments. A pacemaker regulate its rate but can also be influenced by the Autonomic Nervous System
• In single circulation, blood flows to and from the heart through a single pathway, whereas in double circulation there are two separate pathways that are connected to the heart through which oxygenated and deoxygenated blood flows.
• Diastolic Pressure - the minimum pressure recorded just prior to the next contraction
• EMBRYONIC DEVELOPMENT OF THE HEART

  • The heart develops from mesoderm, forming cardiogenic cords that merge into a primitive heart tube
  • The tube divides into five regions:
  • Truncus arteriosus
  • Bulbus cordis
  • Primitive ventricle
  • Primitive atrium
  • Sinus venosus