BIOL 1344 Lecture 15 Outline of Last Lecture I. Adrenal GlandsA. Adrenal MedullaB. Adrenal CortexII. PancreasIII. Diabetes Types Outline of Current Lecture IV. Respiratory SystemA. Upper Respiratory SystemB. Lower Respiratory System Current LectureRespiratory System – Our lungs are the negative pressure type, this means that air is drawn in, not forced. The uptakeof gases in our air has to do with solubility and pressure. Oxygen gas is transported from the lungs to the tissues, carbon dioxide travels from the tissues to the lungs. The upper respiratory system includes the 1. Nose2. Nasal passage (nasal conchae, olfactory, and epithelium)3. Pharynx (1 – nasopharynx 2- oropharynx: adenoids or tonsils and 3 – laryngopharynx: larynx which is supported by thyroid cartilage in the front, cricoid cartilage in the back, and also the paired hyaline cartilages arytenoid, cuneiform, and corniculate. The larynx also includes the epiglottis which is an elastic cartilage which closes the glottis, or air passage, when swallowing. The larynx has vestibular folds which are superior and have no roll in sound production “false vocal cords” as well as the vocal folds which are inferior and are the true vocal cords which articulate speech. Briefly about speech, it is produced in the Broca’s area of the brain and humans are the only creatures who can actually talk. In order to create sound, tongue muscles are also required. Sound comes out in waves. The loudness of sound is measured in Bel which are very large so more commonly decibel or dB. 60-70 dBs is normal conversation levels. Amplitude measures the height of sound waves. Frequency is the pitch, it is measured in Hertz. These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.The lower respiratory passage continues with4. Trachea (has 15-20 rings of hyaline cartilage and 2 sections, the right bronchus which is wider and vertical and left bronchus which is horizontal).5. Secondary bronchi (10-12 divisions branching off from the trachea).6. Tertiary bronchi 7. Bronchioles (have no supporting rings just smooth muscles so they are collapsible. About 1 mm in diameter and provide the maximum resistance to air flow). 8. Terminal bronchioles (from the trachea to the terminal bronchioles is the conducting zone of the respiratory passage).9. Respiratory bronchioles 10. Alveolar ducts11. Alveolar sac12. Alveoli (300-400 million, this is where gas exchange occurs at a rate of P = 2T/r where T= surface tension and r = radius. Pressure gradient determines where gases (oxygen and carbon dioxide) flow. There are type 1 cells which have to do with gas exchange. Type 2 cells have to do with surfactant which reduces surface tension and provides more expansion. Surfactant develops around 28-32 weeks in utero so if a baby is born too pre-maturely they must be connected to a respirator or incubator with added surfactant so that their lungs don’t collapse. If they collapse this is called atelectasis). From the respiratory bronchioles to the alveoli is called the respiratory
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