Review slides Lecture Exam 3

1. Review slides Lecture Exam 3

2. Respiratory System Respiration (in the respiratory system) is the process of exchanging gases between the atmosphere and body cells. It consists of the following events (in order): • *pulmonary ventilation • *external respiration • transport • internal respiration • cellular respiration Functions of the respiratory system We breathe: 1. To provide O2 for cellular respiration and 2. To rid our bodies of CO2 (waste gas)

3. Organs of the Respiratory System Upper respiratory tract – nose, nasal cavity, sinuses, and pharynx Lower respiratory tract – larynx, trachea, bronchial tree, lungs Conducting portioncarries air; nose to the terminal bronchioles Respiratory portion exchanges gases; respiratory bronchioles and alveoli

4. Mucous in Respiratory Tract Respiratory mucosa lines the conducting passageways and is responsible for filtering, warming, and humidifying air. Pseudostratified, ciliated columnar epithelium with goblet cells Respiratory epithelium is interrupted by stratified squamous epithelium in the oro- and laryngopharynx

5. Nose and Paranasal Sinuses The nose: 1) warms 2) cleans 3) humidifies air Paranasal sinuses are mucus membrane-lined, air-filled spaces in maxillary, frontal, ethmoid, and sphenoid bones that drain into the nasal cavity Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001 • Sinuses: • Reduce skull weight • Serve as resonating chambers

6. Inelastic Vestibular folds Covered by folds of laryngeal epithelium that project into glottis Protective Sound Vocal folds (cords) Elastic Larynx Prevents swallowed material from passing into trachea = major components of larynx Posterior Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001

7. Trachea & Primary Bronchi Posterior (Smooth muscle) Note that the trachea is anterior to the esophagus (T5) (T6) Anterior C-rings of cartilage: 16-20 incomplete rings completed posteriorly by trachealis musclekeep trachea open (patent) Figures from: Martini, Anatomy & Physiology, Prentice Hall, 2001

8. Bronchial Tree (No cartilage,few/no smooth muscle) (Cartilage + smooth muscle) (Smooth muscle) Bronchi Bronchioles Alveolar structures Primary Secondary (lobar) Tertiary (segmental) Alveolar ducts Alveolar sacs Alveoli Intralobular Terminal Respiratory Trachea respiratory portion conducting portion Know this chart

9. Bronchial Tree Hilus of lung is the medial opening for air passageways, blood vessels, nerves, and lymphatics. Carina Bronchi - Primary; w/ blood vessels - Secondary (lobar); two on left, three on right - Tertiary (segmental); supplies a broncho- pulmonary segment; 10 on right, 8 on left Bronchioles - Intralobular; supply lobules, the basic unit of lung - Terminal; 50-80 per lobule - Respiratory; a few air sacs budding from theses Bronchioles are to the respiratory system what arterioles are to the circulatory system Intralobular Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001

10. Lobules of the Lung The Lobule is the basic unit of structure and function in the lung (Intralobular) Terminal and respiratory bronchioles are lined with cuboidal epithelium, few cilia, and no goblet cells Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001

11. Gases and Pressure • Our atmosphere is composed of several gases and exerts pressure • 78% N2, 21% O2, 0.4% H2O, 0.04% CO2 • 760 mm Hg, 1 ATM, 29.92” Hg, 15 lbs/in2,1034 cm H2O • Each gas within the atmosphere exerts a pressure of its own (partial) pressure, according to its concentration in the mixture (Dalton’s Law) • Example: Atmosphere is 21% O2, so O2 exerts a partial pressure of 760 mm Hg. x .21 = 160 mm Hg. • Partial pressure of O2 is designated as PO2

12. Normal Inspiration An active process • Intra-alveolar (intrapulmonary) pressure decreases to about 758mm Hg as the thoracic cavity enlarges (P  1/V) • Atmospheric pressure (now higher than that in lungs) forces air into the airways • Compliance – ease with which lungs can expand Phrenic nerves of the cervical plexus stimulatediaphragm to contract and move downward and external (inspiratory) intercostal muscles contract, expanding the thoracic cavity and reducing intrapulmonary pressure. Attachment of parietal pleura to thoracic wall pulls visceral pleura, and lungs follow.

13. Maximal (Forced) Inspiration Thorax during normal inspiration • Thorax during maximal inspiration • aided bycontraction ofsternocleidomastoid and pectoralis minor muscles Compliance decreases as lung volume increases Costal (shallow) breathing vs. diaphragmatic (deep) breathing

14. Normal Expiration • due to elastic recoil of the lung tissues and abdominal organs • a PASSIVE process(no muscle contraction involved, no energy needed) Normal expiration is caused by - elastic recoil of the lungs (elastic rebound) and abdominal organs - surface tension between walls of alveoli (what keeps them from collapsing completely?)

15. Maximal (Forced) Expiration • contraction of abdominal wall muscles • contraction of posterior (expiratory) internal intercostal muscles • An active, NOT passive, process

16. Terms Describing Respiratory Rate • Eupnea – quiet (resting) breathing • Apnea – suspension of breathing • Hyperpnea – forced/deep breathing • Dyspnea – difficult/labored breathing • Tachypnea – rapid breathing • Bradypnea – slow breathing Know these

17. Alveoli and Respiratory Membrane • Respiratory Membrane consists of the walls of the alveolus and the capillary, and the shared basement membrane between them Mechanisms that prevent alveoli from filling with fluid: • cells of alveolar wall are tightly joined together • 2) the relatively high osmotic pressure of the interstitial fluid draws water out of them • 3) there is low pressure in the pulmonary circuit Surfactant resists the tendency of alveoli to collapse on themselves.

18. Diffusion Through Respiratory Membrane The driving for the exchange of gases between alveolar air and capillary bloodis the difference in partial pressure difference between the gases. alveolus tissues Because O2 and CO2 are relatively insoluble in H2O (plasma), RBCs are used to carry or transform these gases.

19. Oxygen Transport • Most oxygen binds to hemoglobin to formoxyhemoglobin (HbO2) • Oxyhemoglobin releases oxygen in the regions of body cells • Much oxygen is still bound to hemoglobin in the venous blood Tissues Lungs But what special properties of the Hb molecule allow it to reversibly bind O2?

20. The O2-Hb Dissociation Curve Recall that Hb can bind up to 4 molecules of O2 = 100% saturation At 75% saturation, Hb binds 3 molecules of O2 on average Sigmoidal (S) shape of curve indicates that the binding of one O2 makes it easier to bind the next O2 This curve tells us what the percent saturation of Hb will be at various partial pressures of O2

21. Oxygen Release • Amount ofoxygen released from oxyhemoglobinincreases as • partial pressure of carbon dioxide increases • the blood pH decreases and [H+] increases (Bohr Effect; shown below) • blood temperature increases (not shown) • concentration of 2,3 bisphosphoglycerate (BPG) increases (not shown)

22. Carbon Dioxide Transport in Tissues • dissolved in plasma (7%) • combined with hemoglobin as carbaminohemoglobin(15-25%) • in the form of bicarbonate ions (68-78%) CO2 + H2O ↔ H2CO3 H2CO3 ↔ H+ + HCO3- CO2 exchange in TISSUES

23. Carbon Dioxide Transport in Lungs CO2 exchange in LUNGS

24. Summary of Gas Transport PO2 = 40 mm Hg PO2 = 95 mm Hg PO2 = 104 mm Hg PO2 = 40 mm Hg T I S SUES LUNGS PCO2 = 45 mm Hg PCO2 = 40 mm Hg PCO2 = 40 mm Hg PCO2 = 45 mm Hg CO2 + H2O ← H2CO3 ← H+ + HCO3- H+ + HCO3- ← H2CO3 ← CO2 + H2O

25. Control of Respiration • Control of respiration is accomplished by: 1) Local regulation 2) Nervous system regulation • Local regulation •  alveolar ventilation (O2),  Blood flow to alveoli •  alveolar ventilation (O2),  Blood flow to alveoli •  alveolar CO2, bronchodilation •  alveolar CO2, bronchoconstriction

26. Control of Respiration • Nervous System Control • Normal rhythmic breathing -> DRG in medulla • Forced breathing -> VRG in medulla • Changes in breathing • CO2 is most powerful respiratory stimulant • Recall: H2O + CO2↔ H2CO3 ↔ H+ + HCO3- • Peripheral chemoreceptors (aortic/carotid bodies) •  PCO2,  pH ,  PO2 stimulate breathing • Central chemoreceptors (medulla) •  PCO2,  pH stimulate breathing

27. Overview of the Endocrine System • The endocrine system consists of • - collections of cells located in tissues scattered throughout the body • - that produce substancesreleased into the blood (hormones) • - to ultimately affect the activity and metabolism of target cells.

28. Classification of Hormones Amino acids Amino Acid Derivatives Peptides Proteins, glycoproteins Hormones Steroids (cholesterol-derived) Lipid Derived Eicosanoids (cell membranes)(locally acting)

29. Actions of Steroid Hormones • hormone crosses membranes • hormone combines with receptor in nucleus or cytoplasm • synthesis of mRNA activated • mRNA enters cytoplasm to direct synthesis of protein, e.g., aldosterone->Na/K Pump (Thyroid hormone has a similar mechanism of action, even though it is a tyrosine derivative) Magnitude ofcellular responseproportional to the number of hormone-receptor complexes formed

30. Actions of Amino Acid-Derived Hormones • hormone (first messenger) binds to receptor on cell membrane • adenylate cyclase activated • ATP converted to cAMP • cAMP (second messenger) promotes a series of reactions leading to cellular changes Magnitude of response is not directly proportional to the number of hormone-receptor complexes – it’s amplified

31. Control of Hormonal Secretions • primarily controlled by negative feedback mechanism 3) Humoral 1) Hormonal 2) Neural Control mechanisms for hormone release

32. Target Cell Activation By Hormones • Target cells must have specific receptors to be activated by hormones • Magnitude of target cell activation depends upon • Blood levels of the hormone • Rate of release from producing organ • Rate of degradation (target cells, kidney, liver) • Half-life • Relative numbers of receptors for the hormone • Cellular receptors can be up- or down-regulated • Affinity (strength) of binding of the hormone to its receptor

33. Pituitary Gland Control • Hypothalamic releasing hormones stimulate cells of anterior pituitary (adenohypophysis) to release their hormones • Nerve impulses from hypothalamus stimulate nerve endings in the posterior pituitary (neurohypophysis) gland to release its hormones Note the hypophyseal portal system of the adenohypophysis (two capillaries in series)

34. Hormones of the Anterior Pituitary (SeT GAP) (an ‘axis’) Tropic hormonescontrol the activity of other endocrine glands All anterior pituitary hormones use second messengers

35. Overview of the Pituitary Hormones Figure from: Martini, Anatomy & Physiology, Prentice Hall, 2001 All anterior and posterior pituitary hormones bind to membrane receptors and use 2nd messengers (cAMP) SeT GAP

36. Hormone Summary Table I Se(x) T G A P

37. Hormone Summary Table II

38. Renin-angiotensin Pathway

39. Stress • Types of Stress • physical stress • psychological (emotional) stress • (Stress is any condition, physical or emotional, that threatens homeostasis) • Stress Response (General Adaptation Syndrome [GAS]) • hypothalamus triggers sympathetic impulses to various organs • epinephrine is released • cortisol is released to promote longer-term responses • Three general phases of the GAS to stress ARE: • Alarm phase • Resistance phase • Exhaustion phase

40. Responses to Stress Exhaustion -  lipid reserves - production of glucocorticoids - electrolyte imbalance - damage to vital organs

41. GH Abnormalities Growth Hormone Ups and Downs • Gigantism - hypersecretion of GH in children • Acromegaly – hypersecretion of GH in adults • Dwarfism – hyposecretion of GH in children Age 9 Age 16 Age 33 Age 52

42. Diabetes (= Overflow) • Diabetes Mellitus (DM) • Hyposecretion or hypoactivity of insulin • Three P’s of Diabetes Mellitus (mellitum = honey) • Polyuria (increased urination) • Polydipsia (increased thirst) • Polyphagia (increased hunger) • Hyperglycemia, ketonuria, glycosuria • Renal Glycosuria • excretion of glucose in the urine in detectable amounts • normal blood glucose concentrations or absence of hyperglycemia • Diabetes Insipidus (insipidus = tasteless) • Hyposecretion or hypoactivity of ADH • Polyuria • Polydipsia