The Thoracic Cavity PPT

June 28, 2012 | By | Reply More

The Thoracic Cavity PPT

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The Thoracic Cavity

Boundaries of and Structures Within

Cavities

  1. Dorsal body cavity
  2. Ventral body cavity

–       Abdominopelvic

  • Abdominal
  • Pelvic

–       Divided by Diaphragm

–       Thoracic

  • 2 Pleural
  • Mediastinum

 

Serous membrane = Serosa

–        Outer layer = PARIETAL serosa

–        Inner layer = VISCERAL serosa

  • Between them = Serous Cavity containing Serous Fluid

–        Serous fluid is blood filtrate + secretions by 2 layers of membrane

–        Allows movement of organs with reduced friction

  • Types of Serous Membranes

–        Pleural = surrounds lungs

–        Pericardium = surrounds heart, slightly modified

–        Peritoneal = surrounds some abdominal organs

Pleural Cavities

  • Surround the lungs
  • Pleural fluid secreted by pleural membranes
  • Holds layers together
  • Reduces friction of organs
  • Compartmentalization
  • 2 Layers

–       Parietal pleura (outer)

  • inner surface of thoracic wall
  • superior surface of diaphragm
  • lateral surface of mediastinum

–       Visceral pleura (inner)

  • root of lungs marks transition
  • external surface of lungs
    Pleural Abnormalities
    Pleural Effusion

–       Excess fluid in the pleural cavity

–       More than 20X

  • Usually less than 1 ml of fluid
    Pneumothorax

–       Air located in pleural space

 

  • Respiratory Tract
  • Upper Respiratory Tract

–       Superior to Larynx

  • Lower Respiratory Tract

–       Larynx

–       Trachea

–       Primary Bronchi

–       Secondary Bronchi

–       Rest of Bronchial Tree

–       Lungs

 

  • Trachea = windpipe
  • Starts at Larynx and travels through mediastinum
  • Located Anterior to Esophagus
  • Trachea terminates into 2 primary bronchi entering lungs
  • Walls contain 16-20 “C” shaped rings Hyaline Cartilage
  • Trachealis Muscle (smooth muscle and soft CT)
  • Layers (deep to superficial)

–        Mucosa = Ciliated Psuedostratified Epithelium

–        Submucosa- contains seromucous glands

–        Adventitia – made of connective tissue, contains cartilage rings

  • Bronchial Tree
  • Primary (main) Bronchi

–        Bifurcation of trachea

–        Basically the same structure

–        Cartilage plates replace rings

–        Posterior to pulmonary vessels

–        Right is wider, vertical, shorter

  • Secondary (lobar) Bronchi

–        Each primary bronchi divides

–        Same structure as primary bronchi

–        Right lung has 3, Left has 2

  • Tertiary (segmental) Bronchi
  • Up to 23 divisions
  • Bronchial Tree (continued)
  • Bronchioles

–       further divisions, < 1 mm diameter

  • Terminal Bronchioles

–       further divisions, 0.5 mm diameter

  • Respiratory Zone

–       Respiratory Bronchioles

–       Alveolar Ducts

–       Alveolar Sacs

  • Terminal bunches of Alveoli
  • Respiratory exchange chamber
    • Respiratory Zone (continued)
    • Lining the Walls of Alveoli

–       Respiratory Membrane

  • Type I cells = simple squamous epithelial cells
  • Basal lamina and fine areolar CT
  • Covered with capillaries and elastic fibers

–       Gas exchange

  • Oxygen into blood
  • Carbon Dioxide into alveoli

–       Type II cells = cuboidal epithelial cells

  • Secrete fluid containing surfactant
    • Throughout Bronchial Tree
    • Psuedostratified columnar changes to simple columnar to simple cuboidal
    • Cartilage rings replaced by cartilage plates once bronchi enter the lungs
    • Smooth muscle and Elastic fibers remain important
    • In Bronchioles

–       Ciliated mucosa disappears, replaced by macrophages in alveoli

–       Cartilage disappears

–       Smooth muscle forms bands around smallest bronchi and bronchioles (not found around alveoli)

 

  • LUNGS (continued)
  • Located in Pleural Compartments
  • Lateral to Mediastinum
  • Location

–         Apex posterior to clavicle

–         Base lays on Diaphragm

–         Costal Surface = Ant, Lat, Post surfaces contact ribs

  • Left Lung = 2 lobes

–         Upper

–         Lower

–         Oblique Fissure

–         Cardiac Notch

  • Right Lung = 3 lobes

–         Upper

–         Middle

–         Lower

–         Oblique fissure

–         Horizontal fissure

  • LUNGS
  • Hilus- medial indentation
  • Root of Lung = structures enter each lung

–        2 Pulmonary Veins = carries O2-rich  blood from each lung to heart

–        1 Pulmonary Artery = carries O2-poor blood to each lung

–        Primary Bronchus

–        Nerves

Lymph Vessels

Specific Location of Lungs

  • Right Lung

–       1” above Rib 1

–       Crosses Costal Cartilage 6

–       Midclavicular at Rib 6

–       Midaxillary at Rib 8

–       Vertebral Border at Rib 10

–       Inferior border 2 rib widths above diaphragm

  • Left Lung

–       1” above Rib 1

–       Deep to Manubroclavicular joint

–       Midsternally to Rib 4

–       Jogs to left, continues to Rib 6

–       Midaxillary Rib 8

–       Vertebral Border at Rib 10

 

  • Lung Lobes
  • Lobes are anatomically + functionally separate
  • Lung lobes divided into Lobules

–       Functionally separate

–       Separated by dense CT

–       Vary in size

  • Stroma = lung tissue

–       CT

–       Many elastic fibers

  • Esophagus
  • Esophagus

–         Pharynx to Stomach

–         Passes thru diaphragm at esophageal hiatus

–         Anterior to vertebrae, Posterior to trachea

  • Layers of Esophagus (deep to superficial)

–         Mucosa

  • Stratified squamous epithelium
  • Lamina propria (loose CT)
  • Muscularis mucosae

–         Submucosa

–         Muscularis Externa

  • Circular/Longitudinal layers
  • Skeletal m, Mix, then Smooth m

–         Adventitia

  • Fibrous CT
    • The Diaphragm
    • Skeletal Muscle
    • Dome-shaped (relaxed)
    • Flattens (contracts)
    • Divides thoracic & abdominopelvic cavities
    • Attachments

–       O: Inferior Internal rib cage, Lumbar vertebrae (by crura)

–       I: Central tendon

  • Innervated by right + left PHRENIC Nerves
  • Action of the Diaphragm
  • Primary muscle of respiration (involuntary)

–        Contraction during inspiration

  •  Increases volume of thoracic cavity
  •  Decreases pressure of thoracic cavity
  • Air moves into lungs  (highàlow pressure)
    • Forced contraction (voluntary)

–        Used for defecation, urination, labor

  • Decreases volume of abdominal cavity
  • Increases pressure in abdominal cavity
  • Pushes on abdominal organs to move contents out
    • Thoracic Cavity Capacity is Increased by:
    • Contraction of diaphragm
    • Intercostal muscles elevate ribs
    • Rib elevation causes the sternum to move anteriorly
    • Openings of Diaphragm
    • PosterioràAnterior
    • Aortic Hiatus

–       Aorta

–       Azygos vein

–        Thoracic duct

  • Esophageal Hiatus

–        Esophagus

–        Vagus nerve

  • Caval Opening

–       Inferior Vena Cava

–       Right Phrenic Nerves

  • Vena Cava
  • Superior Vena Cava

–       in Superior mediastinum, right side

–       Receives blood from regions above diaphragm

–       Formed from Rt + Lft Brachiocephalic Veins cranially

–        Azygos Vein empties into it just superior to heart

–       Empties into Right Atrium

  • Inferior Vena Cava

–       in Inferior mediastinum (right side), runs through abdomen

–       Returns blood to heart from regions below diaphragm

–       Formed from Rt + Lft Common Iliac Veins

–       Empties into Right Atrium

–       Widest blood vessel in body

 

Veins of Thoracic Cavity

  • Vena Cavae
  • Azygos Vein

–       “unpaired”

–       right side of vertebral bodies (at level of T12)

–       runs superiorly

–       empties into Sup. Vena Cava

–       drains right posterior intercostal veins

–       Connects to hemiazygos and accessory hemiazygos that drain left side

 

 

Lymphatic Ducts

  • Thoracic Duct

–       Receives lymph from large trunks in abdomen and thorax

–       Receives lymph from ducts of thoracic lymph nodes

–       Along vertebral bodies

–       Contain valves to ensure 1-way flow of lymph to lymph nodes

–       Drains into left Brachiocephalic Vein (or subclavian or int. jugular veins)

  • Thymus Gland
  • Lymphatic Organ
  • 2-lobed w/lobules
  • Sits on heart and great vessels
  • Immature lymphocytes mature into T-lymphocytes
  • Secretes Thymic Hormones: help T-lymphocytes gain immunocompetence
  • Decreases in size w/age
  • Functional tissue is replaced with fatty tissue
  • Thymus Gland
  • Increases in size during childhood
  • Decreases in size during adulthood
  • Contains lobes and lobules

–       Capsule

–       Cortex

–       Medulla

 

 

Category: Medical

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