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PEKN 1P90 REVIEW SESSION

PEKN 1P90 REVIEW SESSION . Purpose of the Cardiovascular System. Responsible for controlling homeostasis 2 major adjustments necessary for exercise: Increase in cardiac output Redistribution of blood flow form inactive organs to working muscles. The Vascular System .

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PEKN 1P90 REVIEW SESSION

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  1. PEKN 1P90 REVIEW SESSION

  2. Purpose of the Cardiovascular System • Responsible for controlling homeostasis • 2 major adjustments necessary for exercise: • Increase in cardiac output • Redistribution of blood flow form inactive organs to working muscles

  3. The Vascular System

  4. Arteries 4mm diameter • Made up of elastic walls and smooth muscle • Large radius for low resistance • Pressure reservoir • Why is this?

  5. Arterioles30um diameter • Branches of the arteries • Vasodilation/ vasoconstriction • What allows this function? • Control of blood flow mechanisms: • Hormonal control • Neural control

  6. Capillaries8 um diameter • Microscopic blood vessels • Allow for only one blood to pass through at a time • Thin walls • Why is this significant • Precapillary sphincter • What does this do?

  7. Venules • Where the capillaries drain to • Carry the deoxygenated blood to the veins

  8. Veins 5mm • Walls- elastic tissue and smooth muscle • Major Functions of the Veins • Can pool large amounts of blood • Returns blood to the heart • Hardware of the veins • Skeletal muscle pump • Valves

  9. Distribution of Blood • heart 9% • Arteries 11% • Arterioles/ capillaries 7% • Veins/ venules 61%

  10. Local Control • Vessels control their own blood flow depending on the needs of the tissues they supply • Ex vasodialtion occurs as a result of the following stimuli • Greater oxygen required • Decrease in available nutrients • Increase in carbon dioxide, hydrogen ions, lactic acid

  11. Neural Control • Muscles innervated- sympathetic nerves • Why is this? • Hint method of controlling blood flow

  12. Blood Pressure • Definition? • Rises and falls in correspondence to the phases of the cardiac cycle • Systolic pressure • Max pressure achieved during ventricular contraction • Diastolic pressure • Max pressure achieved during ventricular relaxation • Pulse pressure • difference between the systolic and diastolic BP

  13. Normal BP vs Hypertension • Normal • Resting BP- 120/80mm Hg • What is the pulse pressure • Hypertension • High BP – ex 140/90 • Pulse pressure? • REGULAR EXERCISE LOWERS RESTING BP!

  14. MAP- mean arterial blood presssure • Average pressure during a cardiac cycle • Determines rate of blood flow MAP = DBP +[.333(PP)]

  15. Factors affecting MAP • Heart Action • Blood Volume • Total Peripheral Resistance • Viscosity

  16. Know your major vessels! • HINT- Try making up flashcards

  17. RESPIRATORY SYSTEM

  18. Cardiorespitory System • Cardiovascular and Respitory work together to • Deliver____________ • Remove___________

  19. Pulmonary Ventilation • Movement of air into and out of lungs aka? • Relies on differences in air pressure • Air moves from_______pressure to _______pressure

  20. External and Internal Respiration • External • Exchange of O2 and CO2 between the ______ and the ______ • Occurs as a result of breathing • Internal (tissue) • Exchange of O2 and CO2 between the______ and the ______

  21. Upper Airways

  22. Respitory Tract

  23. The Nose • FUNCTION? • Warms, cleans, humidifies air • Look over structure in your textbook! • Hairs- block inhalation of large particles • Conchae/ meatuses- ensure turbulent flow of air

  24. Pharynx • Muscular funnel • 3 regions • What are they? • Nasopharynx • Oropharynx • Laryngopharynx

  25. The Larynx • Voicebox • Keeps food and drink out of airway

  26. Trachea • Wind pipe • Structure? • 12 cm long rigid structure supported by c-shaped rings

  27. Bronchi • Trachea branches at inferior end into the bronchi • R and L _______ Bronchi • Branch again into secondary bronchi and then once more into _____ bronchi

  28. Lungs • Gas exchange with ______ • Average adult lung volume 4-6L • Weighs 1 Kg • During 1second of max exercise there is a max of L of blood in the vessels of the lungs • Refer to textbook for anatomy • Example question why does one lung have an impression, and which side is it on?

  29. Broncioles • Next branch off of the tertiary bronchi- 1mm or less in diameter • Smooth muscle layers • Divides into terminal bronchioles, then respiratory bronchioles, which then moves into the aveoli

  30. Aveoli • Grape like clusters at the end of the respitorybroncioles • Large surface area • Why? • For DIFFUSION!Lungs contain over 300 million aveoli • Aveolar tissue has largest blood supply of any organ in the body • Rest ~ 250mL O2/min leaves aveoli into blood 200mL CO2/min leaves blood into aveoli • 25X more with heavy exercise!!!

  31. Atmospheric Pressure • Remember what drives ventilation? • Note: normal air pressure = 1atm = 760mmHg BOYLES LAW • Pressure of a given quantity of gas is inversely proportional to its volume • Meaning if high pressure, air will move out

  32. Mechanisms of Ventilation • INSPIRATION • Occurs when pressure in lungs is ______ than atmospheric pressure • Muscles involved: external intercostals, diaphragm • EXPIRATION • Occurs when pressure in lungs is _____ than atmospheric pressure • Muscles involved: internal intercostals, rectus femoris

  33. Inspiration • Nerve impulses carried to muscles in diaphragm • Causes muscle to contract • As diaphragm shrinks, size of thoracic cavity increases • Which decreases pressure (like a vacuum) • Atmospheric pressure is now greater than pressure in the lung • Therefore, lungs become inflated

  34. Expiration • Sternum and ribs move down as diaphragm relaxes • Decreases volume in lungs (recoil) • Increases pressure in the lungs • Forces air out of lungs

  35. Lung Volumes and Capacities • Tidal Volume (TV) • Volume of air either inspired or expired prer breath • Rest~ 0.5L air /breath • Exercise _____ TV • Amount of air expired is ~same as air inspired • Inspiratory Reserve Volume (IRV) • Volume of air that can be inhaled during forced breathing in addition to TV • IRV~3L • Expiratory Reserve Volume (ERV) • Amount of air that can be exhaled after a normal expiration • ERV~1.2L

  36. Residual Volume (RV) • Amount of air remaining in lungs after a maximal expiration • ~1.3L • Vital Capacity (VC) • Amount of air that can be exhaled with maximum effort after a maximum inhalation • Test of pulmonary function and strength of thoracic muscles • TV+IRV+ERV • Total Lung Capacity (TLC) • Maximum amount of air the lungs can hold • RV+VC • ~6L

  37. Gas Exchange and Transport

  38. Partial Pressure • Pressure exerted by a single gas in air • What are the three gasses that make up air? • O2, CO2, N2 • Partial Pressure= • % concentration of single gas x total pressure of gas mixture • Dalton’s Law • Sum of the pressures that each gas exerts

  39. The Air we Breathe • O2= 20.93% • N2= 79.04% • CO2= 0.03% • Calculations of Partial Pressures • Calculations of Barometric Pressures and Altitude

  40. Gas Transport by Blood • Plasma • Blood Cells • Differences in PO2 and PCO2 drive gas exchange • Arterial blood has high partial pressure

  41. Oxygen Transport 1) Plasma • 1-2% of O2 transported this way • Henry’s Law • Amount of gas that dissolves in water is determined by its solubility in water and its partial pressure in air • Air has higher partial pressure of O2, than blood

  42. 2) Haemoglobin • 98-99% of O2 transported this way • Molecule made of 4 globular structures • Each containing a haeme group in which O2 binds • When O2 binds to haemoglobin it is the called_______________ • Amount of O2 bound to haemoglobin determined by PO2 • How many O2 molecules need to bind to a haemoglobin molecule to make it 100% saturated?

  43. Oxyhemoglobin Dissociation Curve • Shape of curve reflects properties of Hb molecule • Curve flattens above 90mmHg • Means Hb is fully saturated • Small drop in partial pressure=large decrease in saturation

  44. Carbon Dioxide Transport • CO2 transported to lungs in one of 3 ways • Dissolved in plasma • Bound to Hb • Via Bicarbonate

  45. CO2 Dissolved in Plasma • Amount of CO2 dissolved determined by partial pressure • 7% CO2 transported this way

  46. Carbaminohemoglobin • CO2 binds with amino groups of Hb molecule • NOT the same site that O2 binds to! • Recall: Where does O2 bind to on Hb? • When PCO2 levels decrease, this substance breaks down and CO2 is released • 23% of CO2 transported this way

  47. Bicarbonate • CO2 diffuses into red blood cells • CO2 reacts with water to form carbonic acid • H2CO3 • Red blood cells contain enzyme called Carbonic Anhydrase • This enzyme does what? • Speeds up reaction between CO2 and water • Eventually, carbonic acid breaks down into bicarbonate and hydrogen ions • HCO3 is pumped out of red blood cells and chloride moves in • 70% of CO2 transported this way

  48. Bicarbonate at the Lungs • Bicarbonate re-coverted to CO2 via carbonic anhydrase • CO2 unloads down the pressure gradient

  49. Haldane Effect • Carbaminohemoglobin compounds are reversed as the PCO2 is decreased in the capillaries of the lung • Causes CO2 to move into alveoli • Oxygenation of hemoglobin reduces binding ability for CO2

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