anatomy chapters 23-24

• Airway Resistance


  Resistance to airflow depends upon airway size

  increase size of chest

  airways increase in diameter

  contract smooth muscles in airways

  decreases in diameter
• The Cardiovascular System and Respiratory System


  two systems that cooperate to supply O2 and eliminate CO2
• What are the three basic steps of respiration?


  ventilation (breathing), external (pulmonary) respiration, and internal (tissue) respiration. PIE
• What happens when the respiratory or cardiovascular system fails?


  Failure of either system has the same effect on the body: disruption of homeostasis and rapid death of cells from oxygen starvation and buildup of waste products
• Respiratory is structurally two parts?


  upper respiratory tract is above vocal cords

  lower respiratory tract is below vocal cords
• The conducting zone


  (Functionally) consists of a series of cavities and tubes - nose, pharynx, larynx, trachea, bronchi, bronchiole, and terminal bronchioles - that conduct air into the lungs.
• The respiratory zone


  consists of the area where gas exchange occurs - respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.
• External Nasal Structures


  Skin, nasal bones, & cartilage lined with mucous membrane

  Openings called external nares or nostrils
• Internal Anatomy of nasal structures


  The interior structures of the nose are specialized for

  warming,

  moistening,

  filtering incoming air;

  receiving olfactory stimuli; and

  serving as large, hollow resonating chambers to modify speech sounds.

  The internal portion communicates with the paranasal sinuses and nasopharynx through the internal nares.
• Functions of the Nasal Structures


  Olfactory epithelium for sense of smell

  Pseudostratified ciliated columnar with goblet cells lines nasal cavity

  warms air due to high vascularity

  mucous moistens air & traps dust

  cilia move mucous towards pharynx

  Paranasal sinuses open into nasal cavity

  found in ethmoid, sphenoid, frontal & maxillary

  lighten skull & resonate voice
• Pharynx


  The _________(throat) is a muscular tube lined by a mucous membrane

  The anatomic regions are the nasopharynx, oropharynx, and laryngopharynx.

  The nasopharynx functions in respiration. Both the oropharynx and laryngopharynx function in digestion and in respiration (serving as a common passageway for both air and food).
• Histology of the Pharynx


  Muscular tube (~5 inch long)

  skeletal muscle & mucous membrane

  Extends from internal nares to cricoid cartilage

  Functions

  passageway for food and air

  resonating chamber for speech production

  tonsil (lymphatic tissue) in the walls protects entryway into body

  Distinct regions -- nasopharynx, oropharynx and laryngopharynx
• Larynx


  The ____________(voice box) is a passageway that connects the pharynx with the trachea.

  It contains the thyroid cartilage (Adam's apple); the epiglottis, which prevents food from entering the _______; the cricoid cartilage, which connects the larynx and trachea; and the paired arytenoid, corniculate, and cuneiform cartilages.

  Voice Production

  The __________contains vocal folds (true vocal cords), which produce sound. Taunt vocal folds produce high pitches, and relaxed vocal folds produce low pitches. Other structures modify the sound.
• Cartilages of the Larynx

  Thyroid cartilage forms Adam's apple

  Epiglottis - leaf-shaped piece of elastic cartilage

  during swallowing, larynx moves upward

  epiglottis bends to cover glottis

  Cricoid cartilage-ring of cartilage attached to top of trachea

  Pair of arytenoid cartilages sit upon cricoid

  many muscles responsible for their movement

  partially buried in vocal folds (true vocal cords)
• The Structures of Voice Production

  True vocal cord contains both skeletal muscle and an elastic ligament (vocal ligament)

  When 10 intrinsic muscles of the larynx contract, which move cartilages & stretch vocal cord tight

  When air is pushed past tight ligament, sound is produced (the longer & thicker vocal cord produces a lower pitch of sound)

  The tighter the ligament, the higher the pitch

  Increased volume comes from pushing air harder
• Speech and Whispering


  Is modified sound made by the larynx.

  Requires pharynx, mouth, nasal cavity & sinuses to resonate sound

  Tongue & lips form words

  Pitch is controlled by tension on vocal folds

  pulled tight produces higher pitch

  thicker & longer cords vibrate more slowly producing a lower pitch

  It is forcing air through almost closed rima glottidis -- oral cavity alone forms speech
• Trachea


  The ________(windpipe) extends from the larynx to the primary bronchi.

  It is composed of smooth muscle and C-shaped rings of cartilage and is lined with pseudostratified ciliated columnar epithelium.

  The C-shape of the cartilage allows for smooth passage of food in the esophagus when swallowing.

  The cartilage rings keep the airway open.

  The cilia of the epithelium sweep debris away from the lungs and back to the throat to be swallowed.
• Histology of the Trachea


  Ciliated pseudostratified columnar epithelium

  Hyaline cartilage as C-shaped structure closed by trachealis muscle
• Airway Epithelium


  Ciliated pseudostratified columnar epithelium with goblet cells produce a moving mass of mucus.
• Trachea histology


  Size is ~5 in long & 1 in diameter

  Extends from larynx to ~T5 (fifth thoracic vertebra) anterior to the esophagus and then splits into bronchi

  Layers

  mucosa = pseudostratified columnar with cilia & goblet cells

  submucosa = loose connective tissue & seromucous glands

  hyaline cartilage = 16 to 20 incomplete rings

  open side facing esophagus contains trachealis m. (smooth muscle)

  internal ridge on last ring called carina

  adventitia binds it to other organs
• What is Tracheotomy and Intubation?


  Reestablishing airflow past an airway obstruction

  crushing injury to larynx or chest

  swelling that closes airway

  vomit or foreign object

  Tracheostomy is incision in trachea below cricoid cartilage if larynx is obstructed

  Intubation is passing a tube from mouth or nose through larynx and trachea
• Primary Bronchi


  supply each lung
• The trachea divides into

  the right and left pulmonary bronchi.
• What does the bronchial tree consist of?

  trachea, primary bronchi, secondary bronchi, tertiary bronchi, bronchioles, and terminal bronchioles.
• The walls of bronchi contain?

  rings of cartilage
• Walls if bronchioles contain?


  smooth muscle
• Histology of Bronchial Tree


  incomplete rings of cartilage are replaced by rings of smooth muscle and then connective tissue as branching continues

  Epithelium changes from pseudo stratified ciliated columnar to non ciliated simple cuboidal as pass deeper into the lungs

  *sympathetic NS and adrenal glands release epinephrine that relaxes smooth muscle and dilates airways

  *asthma attack or allergic reactions constrict distal bronchiole smooth muscle closing small airways

  *nebulization therapy = inhale mist with chemicals that relax muscle and reduce thickness of mucuous
• What does the visceral pleura cover?


  lungs, lines ribcage and covers the upper surface of diaphrgm
• Where is the pleural cavity?

  between the ribs and lungs
• Lungs


  ________ are paired organs in the thoracic cavity; they are enclosed and protected by the pleural membrane

  The parietal pleura is the outer layer which is attached to the wall of the thoracic cavity.

  The visceral pleura is the inner layer, covering the ________ themselves.

  Between the pleurae is a small potential space, the pleural cavity, which contains a lubricating fluid secreted by the membranes.

  The pleural cavities may fill with air (pneumothorax) or blood (hemothorax).

  A pneumothorax or a hemothorax may cause a partial or complete collapse of the _____. (atelectasis)

  The _________ extend from the diaphragm to just slightly superior to the clavicles and lie against the ribs anteriorly and posteriorly.
• Secondary bronchi


  supply each lobe of the lungs, 3 right + 2 left
• Tertiary bronchi


  supply each bronchopulmonary segment
• Form a bronchial tree


  repeated branches called bronchioles
• Location and shape of the lungs


  almost totally fill the thorax.

  The right one has three lobes separated by two fissures; the left one has two lobes separated by one fissure and a depression called the cardiac notch (Guess what goes here).
• Each bronchopulmonary segment


  consists of many small compartments called lobules, which contain lymphatics, arterioles, venules, terminal bronchioles, respiratory bronchioles, alveolar ducts, alveolar sacs, and alveoli.
• The secondary bronchi


  give rise to branches called tertiary (segmental) bronchi, which supply segments of lung tissue called bronchopulmonary segments.
• Structures within a Lobule of Lung


  Branchings of single arteriole, venule & bronchiole are wrapped by elastic CT

  Respiratory bronchiole (microscopic)

  Lined with simple squamous epithelium

  This is the first area in the tree where gas exchange can occur

  Alveolar ducts surrounded by alveolar sacs & alveoli

  sac is 2 or more alveoli sharing a common opening
• Alveoli description


  Gas exchange occurs across the alveolar-capillary membrane.

  Alveolar walls consist of type I alveolar (squamous pulmonary epithelial) cells, type II alveolar (septal) cells, and alveolar macrophages (dust cells)

  Type II alveolar cells secrete alveolar fluid, which keeps the alveolar cells moist and which contains a component called surfactant. Surfactant lowers the surface tension of alveolar fluid, preventing the collapse of alveoli with each expiration.

  Infant Respiratory Distress Syndrome is a disorder of premature infants in which the alveoli do not have sufficient surfactant to remain open.
• Cells Types of the Alveoli


  Type I alveolar cells

  simple squamous cells where gas exchange occurs

  Type II alveolar cells (septal cells)

  free surface has microvilli

  secrete alveolar fluid containing surfactant

  Alveolar macrophages, some times called aleolar dust cells

  wandering macrophages remove debris
• Alveolar-Capillary Membrane


  Respiratory membrane = 1/2 micron thick

  Exchange of gas from alveoli to blood

  4 Layers of membrane to cross

  alveolar epithelial wall of type I cells

  alveolar epithelial basement membrane

  capillary basement membrane

  endothelial cells of capillary

  Vast surface area