Chapter 46: The Respiratory System

1.

Q: What is external (physiological) respiration? A: Exchange of gases between blood and atmosphere.

2.

Q: What is internal (cellular) respiration? A: Exchange of gases between blood and tissue; occurs in mitochondria; leads to the production of ATP.

3.

Q: List 3 functions of the respiratory system. A: Providing oxygen to the blood; eliminating carbon dioxide from the blood; forming speech sounds; defending against inhaled microbes; traps and dissolves blood clots; influences arterial concentrations of chemical messengers.

4.

Q: True or False: Thick epithelium facilitates simple diffusion A: False.

5.

Q: What two main properties facilitate simple diffusion? A: THIN epithelium at the respiratory surface and Large surface area.

6.

Q: Choose the statement that is false about the rate of diffusion: a) Increases as surface area increases b) Increases as temperature increases c) Increases with larger concentration gradients d) Increases as the thickness of the membrane increases A: d) Increases as the thickness of the membrane increases. False - a thicker membrane has a slower rate of diffusion. The thinner the membrane, the faster the rate.

7.

Q: Match the animal with its respiratory system: human A: Lungs.

8.

Q: Match the animal with its respiratory system: nudibranch A: External gills.

9.

Q: Match the animal with its respiratory system: insect A: Tracheal system; Extended body surface.

10.

Q: Match the animal with its respiratory system: cuttlefish A: Internal gills.

11.

Q: Match the animal with its respiratory system: flatworm A: Extended body surface.

12.

Q: Match the animal with its respiratory system: bony fish A: Internal gills.

13.

Q: Match the animal with its respiratory system: amphibian A: Positive pressure breathing; Lungs.

14.

Q: Match the animal with its respiratory system: bird A: Parabronchi; Lungs.

15.

Q: Ventilation A: Flow of the respiratory medium (air or water) over the external side of the respiratory surface.

16.

Q: Perfusion A: Flow of blood to the internal side of the respiratory surface.

17.

Q: What are some adaptations in animals with lungs to increase the respiratory surface area? A: Branched tubes, folds, or pockets Ex: bronchioles, alveoli.

18.

Q: Match the medium to "Holds less oxygen" A: water.

19.

Q: Match the medium to "Gas molecules diffuse faster in this medium" A: air.

20.

Q: Match the medium to "Require more energy to move this medium over a respiratory surface" A: water.

21.

Q: Match the medium to "High oxygen content" A: air.

22.

Q: Bony fish have ___ gills covered by ____ A: internal gills covered by opercula.

23.

Q: ____ gills must be immersed in water to keep from collapsing or drying A: External gills.

24.

Q: Water must be continuously brought into ____ gills A: internal gills.

25.

Q: Animals with ____ gills use countercurrent exchange. A: internal gills.

26.

Q: In countercurrent exchange, water flows ____ to the flow of blood under the respiratory surface. A: opposite.

27.

Q: True or false: In countercurrent exchange, the water is more highly oxygenated than the blood. A: True, this forces oxygen to diffuse into the blood.

28.

Q: Insects breathe through air conducting tubes called _______. A: Tracheae.

29.

Q: The finest branches of the trachea are called _____. They form the __________. A: Tracheoles; Respiratory surface.

30.

Q: What do internal air sacs act as in insects? A: Air reservoirs.

31.

Q: What are some characteristics of positive pressure breathing? A: Gulping motion that forces air into the lungs; Occurs in amphibians.

32.

Q: What are some characteristics of negative pressure breathing? A: Muscular contractions that expands the lungs; Lowering the pressure and causing air to be pulled inward. Occurs in reptiles and mammals.

33.

Q: ___________ is attached to the surface of the lungs. A: Visceral pleura.

34.

Q: ___________ lines the cavity itself. A: Parietal pleura.

35.

Q: Tidal Volume A: The volume of air entering and leaving the lung during inhalation and exhalation.

36.

Q: Vital Capacity A: The maximum tidal volume of an individual.

37.

Q: Residual Volume A: The amount of air that remains in the lungs after forceful exhalation.

38.

Q: Control Centers for respiration are located in the ___ and ________ __________. A: Pons and Medulla Oblongata (contains DRG and VRG).

39.

Q: Reduced O2 concentration causes (local control): A: Arteriole walls to contract giving blood more time to pick up O2.

40.

Q: Rising blood O2 concentration causes (local control): A: Arteriole walls to relax, increasing the rate of blood flow through capillaries.

41.

Q: Partial pressure A: The proportion of a gas present in a mixture or the pressure of an individual gas present in a mixture.

42.

Q: What are the two factors that reduce the carrying capacity of Hemoglobin? A: Reduced P(O2) in tissues; Reduced pH in body tissues (Bohr’s effect).

43.

Q: Define physiological respiration. A: The process whereby animals exchange air with the surroundings.

44.

Q: Define cellular respiration. A: Cellular and mitochondrial oxidative reactions for the generation of ATP (OXPHOS).

45.

Q: What is the role of the respiratory medium? A: Facilitates the exchange of gases; the source of oxygen and sink for carbon dioxide.

46.

Q: What type of animals use air as the respiratory medium? A: Terrestrial animals.

47.

Q: What type of organisms use water as the respiratory medium? A: Aquatic organisms.

48.

Q: How does the exchange of oxygen and carbon dioxide occur across the respiratory surface? A: By simple diffusion.

49.

Q: What are the two key properties of a respiratory surface? A: It has to be thin (contains simple epithelium) and possess a large surface area.

50.

Q: Rate of diffusion is inversely proportional to: A: The square of the distance over which diffusion occurs. Requires a thin surface for diffusion to happen.

51.

Q: Rate of diffusion is directly proportional to: A: The surface area across which diffusion occurs. The larger the surface area, the higher the degree of diffusion.

52.

Q: Rate of diffusion gets higher with: A: Larger concentration gradients – gas molecules move from a region of higher concentration to a region of lower concentration.

53.

Q: Define gills. A: Evagination of the body surface.

54.

Q: List three advantages of gills. A: Helps animals to thrive in diverse habitats; efficient means of gas exchange than the skin; large surface area with tiny projections (gill lamellae); rich blood supply; countercurrent flow.

55.

Q: What are external gills? A: Gills that are not protected by external coverings; extend out of the body surface directly in contact with water.

56.

Q: What are two risks associated with external gills? A: High risk of mechanical damage and collapsing; must be kept wet all the time.

57.

Q: What are internal gills? A: Gills located within body coverings protected from mechanical damage and drying.

58.

Q: How do clams and oysters bring water to their internal gills? A: By beating ciliary movement.

59.

Q: How do cuttlefish bring water across their internal gills? A: Use muscle contractions to pump water.

60.

Q: What is the operculum in bony fishes? A: A gill chamber covering.

61.

Q: What are two functions of the operculum? A: Help ventilate the gills; water enters the mouth→flows over the gills→ exits through the gill covers.

62.

Q: What is the primary benefit of countercurrent exchange? A: Maximize gas exchange.

63.

Q: Countercurrent exchange uses what type of water flow over gills? A: One-way flow.

64.

Q: In countercurrent exchange, water moves in what direction to the flow of blood? A: In an opposite direction, thus establishing a favorable concentration gradient.

65.

Q: What are tracheae in insects? A: Outer epidermal invaginations reinforced by chitinous exoskeleton.

66.

Q: How does air enter and exit the tracheal system? A: Through openings called spiracles aided by alternating compression and expansion of the body.

67.

Q: What are tracheoles? A: Finely branched ends of tracheae in contact with body cells.

68.

Q: What is the function of internal air sacs in insects? A: Act as air reservoirs.

69.

Q: When do amphibians typically use their skin for respiration? A: When in aquatic environments.

70.

Q: When do amphibians typically use their lungs for respiration? A: In terrestrial habitats.

71.

Q: Describe positive pressure breathing in frogs. A: A gulping motion that forces air into the lungs.

72.

Q: Lungs evolved as an adaptation for what environment? A: Terrestrial environments.

73.

Q: In lung fishes, lungs evolved as an adaptation to live in what type of environments? A: Oxygen-deprived environments.

74.

Q: How many pairs of air sacs do birds have in addition to their lungs? A: Nine pairs.

75.

Q: What are parabronchi in bird lungs? A: Fine tubes where a capillary network flows in a countercurrent pattern.

76.

Q: How many cycles of inhalation and exhalation are required to move a specific column of air through bird lungs? A: Two cycles.

77.

Q: What is the primary function of lungs in mammals? A: To provide oxygen to the blood.

78.

Q: Where are mammalian lungs located? A: In the pleural cavity lined by pleural membrane.

79.

Q: What is the parietal pleura? A: The layer that lines the pleural cavity.

80.

Q: What is the visceral pleura? A: The layer that lines the lung itself.

81.

Q: What is the interpleural space and what does it contain? A: The space between the pleural layers; contains pleural fluid which protects against friction and helps in cohesion.

82.

Q: What is the diaphragm? A: A dome-shaped muscle situated below the lungs that separates the thoracic cavity from the abdominal cavity.

83.

Q: Describe the texture of mammalian lungs. A: Spongy and elastic.

84.

Q: What is the lung parenchyma responsible for? A: Gas exchange; includes the alveoli, alveolar ducts, and bronchioles.

85.

Q: What type of epithelium lines the alveoli? A: Simple squamous epithelium.

86.

Q: What are Type I pneumocytes responsible for? A: Gas exchange.

87.

Q: What are Type II pneumocytes responsible for? A: The production of surfactant that maintains lung compliance and prevents lung collapse.

88.

Q: How many lobes does the right lung have? A: Three, separated by an oblique and a horizontal fissure.

89.

Q: How many lobes does the left lung have? A: Two, separated by a single oblique fissure.

90.

Q: What is the pathway of air during breathing? A: Nostrils → Pharynx → Larynx → Trachea → Bronchi → Bronchioles → Alveoli.

91.

Q: What structural feature characterizes the larynx, trachea, and large bronchi? A: Cartilaginous rings.

92.

Q: What structural feature characterizes smaller bronchi and bronchioles? A: Smooth muscle.

93.

Q: What are the major muscles involved in inspiration? A: Diaphragm and external intercostal muscles.

94.

Q: Air moves from a region of higher _________ to a region of lower _________. A: Partial pressure to a region of lower partial pressure.

95.

Q: What is the barometric air pressure (atmospheric pressure) at sea level? A: 760 mmHg.

96.

Q: What happens to the diaphragm and external intercostal muscles during normal inspiration? A: They contract, causing the rib cage to pull up and out, increasing intrathoracic volume.

97.

Q: According to Boyle's law, as volume increases, pressure _________. A: Decreases, so air rushes in.

98.

Q: What muscles are involved in forced inspiration? A: Accessory respiratory muscles contract and help the primary inspiratory muscles.

99.

Q: What happens to the diaphragm and external intercostal muscles during normal expiration? A: They relax.

100.Q: What expels air out of the respiratory tract during normal expiration? A: Elastic recoiling of lungs.

101.Q: What muscles are involved in forced or labored breathing during increased oxygen demand? A: Abdominal wall muscles contract and internal intercostal muscles pull the ribs down and inward.

102.Q: List the three respiratory measurements mentioned. A: Tidal volume, Vital capacity, Residual volume.

103.Q: Where are the interneuron groups that modulate respiration located? A: In the pons and medulla.

104.Q: What is the function of the apneustic center in the pons? A: To promote inhalation by constant stimulation of the neurons in the medulla oblongata.

105.Q: What is the function of the pneumotaxic center in the pons? A: To regulate the amount of air that can be taken into the body in each breath.

106.Q: When DRG neurons fire, what happens? A: They stimulate the muscles of inspiration.

107.Q: What happens when DRG neurons stop firing? A: Passive expiration occurs.

108.Q: When do VRG neurons typically fire? A: When ventilation needs are increased (physical activity, exercise, emotional states).

109.Q: What does the firing of VRG neurons stimulate? A: Active expiration.

110.Q: What is the role of chemoreceptors in respiratory regulation? A: They sense the oxygen and carbon dioxide levels in the CSF and the blood and integrate it with the respiratory center neurons to modulate respiration.

111.Q: Where are central chemoreceptors located? A: In the medulla.

112.Q: Where are peripheral chemoreceptors located? A: In the carotid sinus and the aorta.

113.Q: What happens to arterioles in the lungs at low oxygen concentrations? A: The smooth muscle layer constricts, increasing resistance to blood flow and giving more time for oxygen pickup.

114.Q: What happens to arterioles in the lungs when oxygen concentrations are restored? A: They dilate, decreasing resistance to blood flow.

115.Q: Diffusion of gases across the respiratory surface depends on what factor? A: The partial pressure of gases.

116.Q: Define partial pressure of a gas. A: The proportion or pressure of a gas in a mixture.

117.Q: If a gas makes up 20% of a mixture and the barometric pressure is 760 mmHg, what is its partial pressure? A: 152 mmHg (20/100 * 760).

118.Q: What are the approximate partial pressures of oxygen and carbon dioxide in the air? A: Partial pressure of oxygen = 160 mmHg; carbon dioxide = 0.3 mmHg.

119.Q: How do gases move in relation to their concentration gradients? A: They diffuse passively down their concentration gradients.

120.Q: What does the binding of oxygen to hemoglobin do to the carrying capacity of the blood? A: It increases the carrying capacity of the plasma.

121.Q: Where does hemoglobin remain highly saturated with oxygen? A: In the pulmonary capillaries.

122.Q: In the tissues, oxygen dissociates from hemoglobin and moves where? A: Into the cells.

123.Q: What is the Bohr effect? A: The reduced affinity of hemoglobin for blood at increased acidity or low pH.

124.Q: What are the three fates of carbon dioxide at the level of the interstitial fluid and the lungs? A: Remains dissolved in the plasma, binds to hemoglobin, or combines with water to form carbonic acid.

125.Q: What is the role of carbonic anhydrase in carbon dioxide transport? A: It facilitates the conversion of carbon dioxide and water into carbonic acid.

126.Q: How does carbon monoxide affect hemoglobin? A: It has ~240X higher affinity to hemoglobin than oxygen, leading to carbon monoxide poisoning and hypoxia.

127.Q: What is carboxyhemoglobin? A: Hemoglobin bound to carbon monoxide.

128.Q: Role of respiratory system in detecting body pH A: Detects acidic conditions (high CO2), influencing breathing rate to restore homeostasis.

129.Q: Two basic facts of respiration A: Physiological (external) respiration (gas exchange with environment) and cellular (internal) respiration (ATP production in mitochondria).

130.Q: Parts of the upper respiratory tract involved in air preparation A: Nose/nostrils, nasal cavity, pharynx, mucus lining, nasal sinuses warm and humidify air.

131.Q: Structure responsible for voice production and another function of the respiratory system A: Larynx (voice box) produces speech; respiratory system also forms speech sounds.

132.Q: Pathway of air after the larynx A: Larynx → trachea → bronchi → bronchioles → terminal bronchioles → alveoli (gas exchange).

133.Q: Key components of the respiratory system A: Respiratory surfaces, airways (upper and lower respiratory tracts), and lungs (primary organs).

134.Q: Location of the lungs A: Within the thoracic cavity.

135.Q: Physiological respiration A: Gas exchange between the body and the external environment.

136.Q: Major functions of the respiratory system A: Providing oxygen to the blood and eliminating carbon dioxide from the blood.

137.Q: Another important function of the respiratory system A: Influences pH homeostasis.

138.Q: Role of chemoreceptors A: Monitor carbonic acid (PCO2) and pH in the blood.

139.Q: Another function of the respiratory system related to inhaled air A: Defending against inhaled microbes.

140.Q: Epithelium lining the airways and its components A: Pseudostratified ciliated columnar epithelium containing goblet cells (mucus production) and cilia.