ZOO 102: 3RD LONG EXAM

• Respiratory system


  An organ system responsible for the respiration, the process of obtaining oxygen from the external environment and eliminating carbon dioxide
• Circulatory system


  An organ system responsible for the transportation of oxygen, nutrients, hormones, and waste products throughout the body
• Respiratory and circulatory systems

  • Work together to ensure that cells receive the oxygen and nutrients they need for cellular respiration and function, while efficiently removing waste products like carbon dioxide
• Cutaneous respiration


  The direct exchange of gases through the skin, an important supplementary organ for respiration in certain organisms
• Cutaneous respiration


  • Typically involves a thin and moist skin to allow the direct exchange of gases
• Gills


  Respiratory organs that allow the withdrawal of oxygen in water, either internal (associated with pharyngeal slits and pouches) or external (arising from the branchial region as filamentous capillary beds)
• Gill structure


  • Gill filaments (site of gas exchange), gill rakers (appendages along the front edge of the gill arch), gill arches (support the gills)
• Swim bladder


  An elongated gas-filled sac that aids in respiration, originally functioning primarily as a buoyancy organ
• Lungs


  The primary respiratory organs in terrestrial vertebrates, enabling the extraction of oxygen from the air and expulsion of carbon dioxide
• Lungs and associated structures

  • Larynx, trachea, alveoli and bronchi
• Trachea


  Also known as the windpipe, formed by 16 to 20 stacked, C-shaped pieces of hyaline cartilage connected by dense connective tissue
• Larynx


  A cartilaginous structure inferior to the laryngopharynx that connects the pharynx to the trachea and helps regulate the volume of air that enters and leaves the lungs
• Alveoli and bronchi


  The main airways in the lungs, with bronchi branching off into smaller passageways eventually leading into the alveoli, where the exchange of oxygen between the respiratory and circulatory system occurs
• Ciliary pumps


  Facilitate respiratory exchange by ventilating surfaces, allowing the evolution of larger species and protective armor by reducing reliance on cutaneous respiration
• Cilia and surfactants


  • Cilia: hair-like projections that line the respiratory routes, create water currents and facilitate feeding; Surfactants: secretion that lines the lungs and gas bladders, reduces surface tension at the water-air interface
• Muscular pumps


  Facilitate ventilation by contraction and relaxation of respiratory muscles, including ram ventilation (fish's forward locomotion contributing to gill ventilation)
• Muscular ventilation


  • Water-breathing fishes: dual pump system of buccal and opercular pumps; Air-breathing fishes and amphibians: buccal pump; Air-breathing amniotes: aspiration pumps utilizing the rib cage and diaphragm
• Comparative anatomy of vertebrate respiratory systems

  • 5 'naked' gill slits, 2 demibranchs + septum & associated structures (holobranch), 5-15 pairs of gill pouches, simple sacs in amphibians, septate lining in reptiles, air sacs in birds, multi-chambered in mammals
• Embryonic development of the respiratory system

  Begins from the primitive gut tube, with a respiratory diverticulum forming as an outpocketing on the proximal part of the gut tube
• Open circulatory system


  The blood directly diffuses into the cells and body cavities and travels back to the heart via diffusion, resulting in sluggish blood flow, 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, with the presence of hemoglobin, found in all vertebrates and some invertebrates
• Lymphatic system


  An organ system responsible for fluid balance, immune response, and fat absorption, consisting of lymph, lymphatic vessels, and lymphatic tissue
• Cardiovascular system


  An organ system responsible for oxygen and nutrient delivery, and waste removal, consisting of blood, blood vessels, and the heart
• Blood


  A special fluid primarily contained within the blood vessels, primarily produced by hematopoiesis in the bone marrow
• Functions of blood


  • Nutrition (transport of nutrients), Excretion (transport of waste products), Hormonal transport, Homeostasis (thermoregulation and osmoregulation)
• Main components of blood

  • Erythrocytes (RBCs), Leukocytes (WBCs), Plasma, Thrombocytes (Platelets)
• Blood vessels

  Tubes or channels that carry blood throughout the body, including veins, arteries, and capillaries
• Nutrients such as glucose and amino acids are carried to cells


  1. For energy

  2. For metabolism
• Waste products and metabolic byproducts are transported away from tissues


  To be excreted by organs
• Hormones secreted by glands are transported


  To target tissues where they exert their effects
• Blood


  • Contributes to thermoregulation
  • Contributes to osmoregulation
• Main components of blood

  • Erythrocytes (RBCs)
  • Leukocytes (WBCs)
  • Plasma
  • Thrombocytes (Platelets)
• Erythrocytes (RBCs)


  • Contain hemoglobin, primary oxygen transport molecule
• Leukocytes (WBCs)


  • Play a crucial role in the immune system and defend it against infections and pathogens
• Plasma


  Straw-coloured liquid that serves as the medium in which blood cells and various substances are suspended
• Thrombocytes (Platelets)


  • Gather at the site of injury and help in the blood clotting process
• Types of blood vessels

  • Artery
  • Vein
  • Capillary
• Artery

  Carries blood away from the heart
• Vein


  Carries blood back towards the heart
• Capillary


  Assists in the exchange of substances between the blood and tissues