Circulation in Animals

• Importance of the circulatory system in animal physiology:

  • Transport of nutrients and oxygen to different tissues and organs
  • Removal of waste products like carbon dioxide and nitrogenous waste
  • Regulation of body temperature for homeostasis
  • Distribution of hormones to regulate physiological processes
  • Defense against pathogens by carrying white blood cells
• Basic Anatomy of the Human Heart:

  • Heart is a muscular organ responsible for pumping blood throughout the body
  • Divided into four chambers: two atria and two ventricles
  • Atria receive blood while ventricles pump blood out
  • Surrounded by a pericardium for protection and lubrication
• Chambers of the Heart:

  • Atria receive blood (left from lungs, right from body)
  • Ventricles pump blood out (left to body, right to lungs)
• Valves of the Heart:

  • Atrioventricular (AV) Valves: Tricuspid and Bicuspid/Mitral
  • Semilunar Valves: Pulmonary and Aortic
• Blood Vessels:

  • Arteries carry oxygenated blood away from the heart
  • Veins transport deoxygenated blood back to the heart
  • Capillaries facilitate exchange of nutrients, oxygen, and waste products
• Advantages of Fish Circulatory System:

  • Efficiency in aquatic environments
  • Energy conservation due to single circuit
  • Adaptation to oxygen availability in water
• Single-loop Circulatory System in Fish:

  • Consists of heart, gills, and systemic circulation
  • Deoxygenated blood from body to atrium, then ventricle
  • Oxygenation in gills, then systemic circulation to body tissues
• Three-chambered Amphibian Heart and Double-loop Circulatory System:

  • Three-chambered heart with two atria and one ventricle
  • Partial separation of oxygenated and deoxygenated blood
  • Unique adaptation of cutaneous respiration for gas exchange through the skin
• Amphibians have a circulatory system that includes a double set of blood vessels - systemic and pulmonary
• Systemic circulation carries oxygenated blood from the heart to the body tissues, supplying them with nutrients and removing waste products
• Deoxygenated blood returns to the heart for reoxygenation through the pulmonary circulation
• Amphibians do not possess a complete separation of systemic and pulmonary circulation, resulting in some mixing of oxygenated and deoxygenated blood in the ventricle
• Amphibians have nucleated red blood cells, which play a crucial role in carrying oxygen from the lungs, skin, or gills to the body tissues
• Nucleated red blood cells in amphibians can divide, contribute to wound healing, and participate in immune responses
• Amphibian blood also contains white blood cells responsible for immune responses and clotting factors to prevent excessive bleeding
• The circulatory system of amphibians allows them to adapt to both terrestrial (land) and aquatic (water) environments
• When amphibians are on land, their circulatory system helps transport oxygen to their body tissues
• When amphibians transition to an aquatic environment, their circulatory system undergoes physiological changes to adapt to the new conditions
• Gill respiration is crucial for amphibians' survival in aquatic environments, allowing them to respire efficiently while underwater
• The circulatory system of amphibians plays a vital role in facilitating the transition from terrestrial to aquatic environments by adapting to both land-based respiration and gill respiration in water
• The reptilian heart consists of two atria and one ventricle
• Reptiles have a closed circulatory system with a three-chambered heart
• Reptiles have a double circulation system with systemic and pulmonary circulation
• Arteries carry oxygenated blood away from the heart to the body tissues, while veins return deoxygenated blood back to the heart
• Capillaries connect arteries and veins, allowing for the exchange of gases, nutrients, and waste products between the blood and surrounding tissues
• Reptiles have a renal portal system that allows blood from the lower body to pass through the kidneys before returning to the heart
• The circulatory system of reptiles is adapted to meet their metabolic needs, delivering oxygen and nutrients to the tissues and removing metabolic waste products
• Birds have a four-chambered heart that allows for complete separation of oxygenated and deoxygenated blood
• Birds generally have higher heart rates compared to mammals
• Birds have lungs responsible for gaseous exchange, with a high respiratory capacity
• Birds possess air sacs that aid in continuous airflow through the lungs during inhalation and exhalation
• Birds have a higher concentration of red blood cells compared to mammals, allowing for increased oxygen-binding capacity
• The circulatory system in birds is well-adapted for their unique physiological needs, enabling them to sustain high levels of activity and flight efficiently
• Mammals have a four-chambered heart with a clear separation of oxygenated and deoxygenated blood
• The mammalian heart allows for efficient separation of oxygenated and deoxygenated blood, ensuring optimal systemic circulation
• Mammals have a double circulatory system with pulmonary and systemic circulation
• The division of the mammalian heart into four chambers allows for a more efficient functioning, maximizing cardiac output and maintaining adequate blood pressure
• The 4-chambered heart in mammals is adapted to meet the higher metabolic demands of these animals, providing efficient separation and circulation of oxygenated and deoxygenated blood
• Invertebrates have diverse circulation systems depending on the specific group of organisms
• Some invertebrates lack a true circulatory system and rely on diffusion for the distribution of nutrients, respiratory gases, and waste products