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Lab 14 Cardiorespiratory System Anatomy-Part 1: Heart and Lung Anatomy

  • Page ID
    59154
  • Objectives:

    At the end of this lab, you will be able to…

    1. Correctly name and locate the great vessels (Vena Cava, Aorta, Pulmonary Trunk, and Pulmonary Veins)
    2. Correctly identify and indicate the functions of the various chambers of the heart and valves
    3. Correctly identify the structures of the respiratory tract and lungs.
    4. Correctly dissect a Sheep’s heart and identify the major structures following dissection.

     

    Pre-Lab Exercise:

    After reading through the lab activities prior to lab, complete the following before you start your lab

    1.      The right atrium receives blood from the                                and the left atrium receives blood from the                                                                   , while the right ventricle will eject blood to the                                                      and the left ventricle will eject blood to the                                                  .
    2.      There are                          lobes in the right lung and              lobes in the left lung.
    3.      Color the images for use as a reference for identifying the models and dissected specimens.

     

    Materials:

    • Torso Model
    • Heart and Lung Models
    • Sheep’s Heart
    • Dissection pan and dissecting tools
    • Stickers
    • Felt Pens
    • Colored Pencils

     

    The cardiovascular system is one of the most important systems for the body to maintain homeostasis. As it will function to transport materials throughout the body and is highly integrated with all systems of the body, none more so than the respiratory, immune and endocrine systems.  Functionally, the cardiovascular system is comprised of a 4-chamber pump (the cardiac organ or heart) and a closed tubular network that traverses the body.

    Activity 1: Heart Gross Anatomy

    The heart functions within the system as a hydraulic pump, a pump moving fluids, by generating enough compressive force to overcome the fluid pressure of resistance in the vessels. The organ is located within the mediastinum of the thoracic cavity between the pleural cavities of the lungs.  The heart is held within the mediastinum by a fibrous “bag” of connective tissue (pericardium) that allows for the heart to change its volume within a very limited range, changes of volume of heart is typically limited to 75-500 mL. Additionally, the heart has a long axis that is tangential (at an angle) to the long axis of the body, because of the anatomical changes during development. This means that even though we talk about having “left” heart structures and “right” heart structures we can just as easily state we have superior (left) and inferior (right) heart structures. 

    When examining the heart, there are three distinct anatomical features that can be considered the external structures of the heart.  These include the great vessels, the aorta and aortic arch and the pulmonary trunk to the superior and medial aspect of the heart allowing blood to move to the body and lungs, and the vena cava (superior and inferior) and pulmonary veins to the posterior aspect of the heart allowing blood to return from the body and lungs. You will notice that there is an extension of the atrium above the coronary arteries on both the right and the left side of the heart, these are the auricles of the atria and are important in allowing for additional venous return to the heart from either the body (right atria) or lungs (left atria).  This additional return provides for greater volume being moved with each contraction of the heart. There is also the pericardium and fat pad that provide protection and anchorage of the heart within the mediastinum of the thoracic cavity.  These fat pads serve a second function as being a fuel reserve for the cardiac tissues to do work during periods of prolonged effort.

    Because of the aerobic obligated nature of the cardiac muscle, there is an extensive network of blood vessels to allow perfusion within the heart, the coronary vessels. The coronary arteries arise from branching points of the aorta just distal to the aortic valve, but at a point where the valve can easily cover the vessels when open during movement of blood out of the left ventricle. This means that blood will only flow into the coronary vessels when the aortic valve is closed and if the heart contracts too rapidly the valve limits the amount of blood being able to get to the tissues of the heart.

    Internally the heart is an organ structured to allow for constant changes in its internal volume without undergoing damage to the organ.  Some of these changes are seen as myocardium layer intermingles with the endocardium pressing into the internal regions of the chambers and becomes visible forming into the specialized structures of the septum, trabeculae carnae and papillary muscles of the heart. Along with the structures meant to change volume of the heart there are 2 sets of valves that ensure blood will only flow in one-direction through the heart.  These are the atrial-ventricular valves (right and left) that are held in place by the chordae tendinea and papillary muscles and prevent backflow to the atria during ventricular contraction (systole) and the semi-lunar valves (pulmonary and aortic) that prevent backflow to the ventricle during the ventricular relaxation (diastole).

     

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    External Anatomy of the Heart

    1 Aorta                              2 Pulmonary Trunk and Arteries                  3a Superior Vena Cava                                    3b Inferior Vena Cava

    4 Pulmonary Veins           5 Septal Divide                                             6 Auricle of Left Atria                                      7 Auricle of Right Atria

    7a Right Atria                   8 Left Ventricle.                                            9 Marginal Artery & Small Cardiac Vein.       10 Left Atria

    11 Great Cardiac Vein      12 Left Anterior Descending Interventricular Anterior                                                  13 Right Ventricle

    14 Posterior Interventricular Artery                                                        15 Middle Cardiac Vein                                  16 Cardiac Sinus

     

    Color each structure, tissue or organ with a different color to assist with identification

     

     

     

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    Internal Anatomy of the Heart

    1a Superior Vena Cava

    1b Inferior Vena Cava

    2 Right Atria

    3 Right A-V (Tricuspid) Valve

    4 Endocardium

    4a Trabecular Carnae

    5 Chordae Tendineae

    6 Pulmonary Veins

    7 Aorta

    7a Aortic Valve

    8 Pulmonary Trunk

    8a Pulmonary Valve

    9 Pulmonary Arteries

    10 Left Atria

    11 Left A-V (Bicuspid or Mitral) Valve

    12 Papillary Muscle

    13 Myocardium

    14 Epicardium

     

    Color each structure, tissue or organ with a different color to assist with identification

    Procedures:

    1.      Obtain torso and Heart models, stickers, felt pens
    2.      Write names of great vessels and structures of the heart that you are responsible for knowing and identifying on the stickers
            Aorta, Inferior Vena Cava, Superior Vena Cava, Pulmonary Trunk, Pulmonary Veins, Right Atrium, Right Ventricle, Left Atrium, Left Ventricle, Bicuspid (Mitral) Valve,         Tricuspid Valve, Papillary Muscle, Chordae Tendinea, Myocardium, Septum
    3.      Select a “team leader” and use the colored images and reference materials to take turns labeling the model

    a.       As structures are labeled, indicate a function of the structure being labeled. If more than 1 function have members of the group take turns identifying the other functions not mentioned when structure was initially labeled

    4.      Have your instructor check your progress and finish activity two.

     

    Activity 2: Respiratory Tract and Lung Anatomy

    The respiratory system is comprised of two primary organs that are at the terminus of an open lumen (alveoli) that provides an access for air movement from the external environment into the body.  The pathway begins in the cranium (the nasal and oral cavity) and traverses through the ventral/anterior cervical region into the thoracic cage.  The upper tract of the system is responsible for exchange of materials between the body and the external environment, defense against pathogens and harmful particles, and vocalization (speech and sound production) from specialized structures in the larynx (the region of the trachea between the Nasopharynx and the bronchiole branches). The lower tract of the system is responsible for passage of air from the environment to the alveoli, exchange of gasses between the alveoli and the pulmonary capillaries within the lungs.  The pathway of air flow within the system is divided into the trachea, bronchi, bronchial branches, bronchioles, and alveoli.

    While most people associate respiration (ventilation) with the need to “get Oxygen” for their body.  Oxygen (O2) does not regulate the system, carbon dioxide (CO2) or more importantly bicarbonate (H2CO3 or H+ HCO3-) regulates the system.  The action of the respiratory system is termed ventilation and is broken into two distinct components, the inspiratory (inhalation) and expiratory (exhalation) action that leads to the lungs inflating and deflating (they do not expand and contract) proportionally to the movement the thoracic cage.  This inflation and deflation are based on the changes in pressure within the thoracic cage leading to either a pressure less than the environment (inhalation) or pressure greater than the environment (exhalation).

    Procedures:

    1.      Obtain torso and Heart and lung models, stickers, felt pens
    2.      Write names of structures of the respiratory tract and lungs that you are responsible for knowing and identifying on the sticker
                    Nasal Conches, Larynx, Trachea, Primary Bronchi, Secondary Bronchi, Superior Lobe of Right Lung, Middle Lobe of Right Lung, Inferior Lobe of Right Lung,                 Superior Lobe of Left Lung, Inferior Lobe of Left Lung, Horizontal Fissure, Oblique Fissure, Diaphragm

    3.      Select a “team leader” and use the colored images and reference materials to take turns labeling the model

    a.       As structures are labeled, indicate a function of the structure being labeled. If more than 1 function have members of the group take turns identifying the other functions not mentioned when structure was initially labeled

    4.      Have your instructor check your progress and finish activity two.

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    Anatomy of the Respiratory System

    1 Nasal Opening

    1a Nasopharynx

    2 Larynx

    3 Trachea

    4 Bronchi

    5a Right Lung

    5b Left Lung

    5c Pleural Cavity

    6 Diaphragm

     

    Color each structure, tissue or organ with a different color to assist with identification

     

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    Anatomy of the Lower Respiratory Tract

    12 Bronchi

    13a Primary Bronchial Branches

    13b Secondary Bronchial Branches

    13c Tertiary Bronchial Branches

    13d Bronchioles

    14 Right Lung

    14a Upper Lobe Right Lung

    14b Middle Lobe Right Lung

    14c Lower Lobe Right Rung

    15 Left Lung

    15a Upper Lobe Left Lung

    15b Lower Lobe Left Lung

    15c Lingula of Left Lung

    16a Pleural Parietal Lining

    16b Pleural Visceral Lining

    16c Pleural Cavity Space

     

    Color each structure, tissue or organ with a different color to assist with identification

    Activity 3: Dissection of Sheep’s Heart

    Obtain the heart, dissection tray and tool.

    1.      Examine the external anatomy of the heart.

    a.       Find the great vessels (Aorta, Vena Cava, Pulmonary Trunk and Pulmonary Veins) as the junction with the heart.
    b.      Place probes into the vessels and see where you are able to press inside of the heart to determine location of atrium and ventricle of the right and left side of the heart
    c.       Locate the anterior side of the heart and note the interventricular sulcus (you will see the Left Anterior Interventricular Descending Artery and Greater Cardiac Vein in the sulcus). Note the amount of fat around the sulcus and covering the external anatomy of the heart.  Can you think about why the heart might have this level of fat? Discuss in your group and once you have an answer call your instructor over to see how correct your thinking might be.

    2.      Orient so that anterior is facing you and place onto dissection pan so that the right-side of the heart is facing you.
    3.      Dissection of the Right Side:

    a.       Make a coronal incision (along the lateral margin of the heart) with the scalpel through the right side of the heart

    i.     Start the incision at the entrance of the Superior Vena Cava into the Right Atrium
    ii.     Continue along the lateral margin through the atrium and ventricle of the heart
    iii.     Stop when get to the interventricular septum

    1.      The muscle is “thick” but don’t saw. Glide the scalpel through the muscle, have your partner use the forceps and probe to open the slit being made to assist with opening the right ventricle

    b.      Once the incision has been made, press the base and apex of the heart toward each other and use the shear to widen the incision to allow for examination of the internal right atrium and ventricle
    c.       Examine the internal anatomy of the right atrium and ventricle identifying the important anatomical structures that you are responsible for knowing.

    4.      Continue the dissection to the left side.

    a.       Make a coronal incision (along the lateral margin of the heart) with the scalpel

    i.     Start the incision at the Apex of the heart
    ii.     Continue along the lateral margin through the left ventricle of the heart
    iii.     Stop when get to pulmonary trunk and aorta

    1.      The muscle is “thick” but don’t saw. Glide the scalpel through the muscle, have your partner use the forceps and probe to open the slit being made to assist with opening the left ventricle

    b.      Once the incision has been made, open the left side of the heart so that the internal anatomy is visible, but the heart is still a single organ being held at the septum.
    c.       Examine the internal anatomy of the left atrium and ventricle, identifying the important anatomical structures that are responsible for knowing.
    d.      What do you notice about the difference in the structures between the right and left chambers of the heart?  Why would the heart have these anatomical differences? Discuss in your group and once you have an answer call your instructor over to see how correct your thinking might be.

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