Lec_activity15_respiratory_system

NUR11O1 Integrated Human Anatomy and Physiology Department of Biology Institute of Arts and Sciences Far Eastern University

LECTURE ACTIVITIES NO. 15 RESPIRATORY SYSTEM Name: Yda Maxine Palma

Section: 17

Date Submitted: 12/05/2020

I. INTRODUCTION The respiratory system enables breathing as well as the exchange of oxygen and carbon dioxide between the air in the lungs and the blood. In addition, the respiratory organs are also responsible in the transport of gases in the blood and tissues. II. ACCOMPLISH THE ACTIVITY TABLE 1. GUIDE QUESTIONS 15.01A. Describe the functions of the respiratory system.

15.02A. Describe the anatomy of the respiratory passages, beginning at the nose and ending with the alveoli.

ANSWERS The respiratory system exchanges O2 and CO2 between the air and the blood, regulates blood pH, helps produce sounds, moves air over the sensory receptors that detect smell, and protects against some pathogens. 1. The nose consists of the external nose and the nasal cavity. 2. The bridge of the nose is bone, and most of the external nose is cartilage. 3. The nasal cavity warms, humidifies, and cleans the air. The nares open to the outside, and the choanae lead to the pharynx. The nasal cavity is divided by the nasal septum into right and left parts. The paranasal sinuses and the nasolacrimal duct open into the nasal cavity. Hairs just inside the nares trap debris. The nasal cavity is lined with pseudostratified epithelium containing cilia that trap debris and move it to the pharynx. Pharynx 1. The nasopharynx joins the nasal cavity through the choanae and contains the opening to the auditory tube and the pharyngeal tonsils. 2. The oropharynx joins the oral cavity and contains the palatine and lingual tonsils.

©

Biofacultymember2020

NUR11O1 Integrated Human Anatomy and Physiology Department of Biology Institute of Arts and Sciences Far Eastern University

3. The laryngopharynx opens into the larynx and the esophagus. Larynx Larynx 1. The larynx consists of three unpaired cartilages and six paired ones. The thyroid cartilage and cricoid cartilage form most of the larynx. The epiglottis covers the opening of the larynx during swallowing. 2. The vestibular folds can prevent air, food, and liquids from passing into the larynx. 3. The vocal folds (true vocal cords) vibrate and produce sounds when air passes through the larynx. The force of air movement controls loudness, and changes in the length and tension of the vocal folds determine pitch. Trachea The trachea connects the larynx to the main bronchi. Bronchi The main bronchi extend from the trachea to each lung. Lungs 1. There are two lungs. 2. Pharynx > Larynx > Trachea > Main Bronchus > Lobar Bronchus > Segmental Bronchus > Bronchiole > Terminal Bronchiole > Respiratorial Bronchiole > Respiratory Sacs > Alveolar Ducts 3. The epithelium from the trachea to the terminal bronchioles is ciliated to facilitate removal of debris. Cartilage helps hold the tube system open (from the trachea to the bronchioles). Smooth muscle controls the diameter of the tubes (especially the bronchioles). The alveoli are formed by simple squamous epithelium, and they

©

Biofacultymember2020

NUR11O1 Integrated Human Anatomy and Physiology Department of Biology Institute of Arts and Sciences Far Eastern University

facilitate

diffusion

of

gases.

4. The respiratory membrane has six layers, including a film of water, the walls of the alveolus and the capillary, and an interstitial space. The respiratory membrane is thin and has a large surface area that facilitates gas exchange. Pleural Cavities The pleural membranes surround the lungs and provide protection against friction. Lymphatic Supply Superficial and deep lymphatic vessels drain the lungs. 15.02B. Describe the structure of the lungs, and define respiratory membrane.

1.

There

are

two

lungs.

2. Pharynx > Larynx > Trachea > Main Bronchus > Lobar Bronchus > Segmental Bronchus > Bronchiole > Terminal Bronchiole > Respiratorial Bronchiole > Respiratory Sacs > Alveolar Ducts 3. The epithelium from the trachea to the terminal bronchioles is ciliated to facilitate removal of debris. Cartilage helps hold the tube system open (from the trachea to the bronchioles). Smooth muscle controls the diameter of the tubes (especially the bronchioles). The alveoli are formed by simple squamous epithelium, and they facilitate diffusion of gases. 4. The respiratory membrane has six layers, including a film of water, the walls of the alveolus and the capillary, and an interstitial space. The respiratory membrane is thin and has a large surface area that facilitates gas exchange. 15.03A. Explain how contraction of the During the process of inhalation, the muscles of respiration causes changes in lung volume expands as a result of

©

Biofacultymember2020

NUR11O1 Integrated Human Anatomy and Physiology Department of Biology Institute of Arts and Sciences Far Eastern University

thoracic volume during quiet breathing the contraction of the diaphragm and and during labored breathing. intercostal muscles (the muscles that are connected to the rib cage), thus expanding the thoracic cavity. Due to this increase in volume, the pressure is decreased, based on the principles of Boyle's Law. 15.03B. Describe the changes in alveolar Changing Alveolar Volume pressure that are responsible for moving 1. Increasing thoracic volume results in air into and out of the lungs. decreased pleural pressure, increased alveolar volume, decreased alveolar pressure, and air movement into the lungs. 2. Decreasing thoracic volume results in increased pleural pressure, decreased alveolar volume, increased alveolar pressure, and air movement out of the lungs. 15.03C. Explain how surfactant and The role of surfactant is to prevent lungs pleural pressure prevent the lungs from from recoiling too fast by reducing surface collapsing and how changes in pleural tension. Pleural pressure prevents the pressure cause alveolar volume to change. lungs from collapsing by being lower than alveolar pressure, thereby reducing the collapse of the lung. Respiratory Disease Syndrome in premature infants is when there is not enough surfactant. If not treated, the respiration muscles will work too much and the infant will die to inadequate ventilation of the lungs and respiratory muscle fatigue. 15.04A. Explain the factors that affect gas 1. Gas exchange between air and blood movement through the respiratory occurs in the respiratory membrane. membrane. 2. The parts of the respiratory passageways where gas exchange between air and blood does not occur constitute the dead space. Respiratory Membrane Thickness Increases in the thickness of the respiratory membrane result in decreased gas exchange. Surface Area

©

Biofacultymember2020

NUR11O1 Integrated Human Anatomy and Physiology Department of Biology Institute of Arts and Sciences Far Eastern University

15.04B. Describe the partial pressure gradients for O2 and CO2.

15.05A. Explain how O2 and CO2 are transported in the blood.

Small decreases in surface area adversely affect gas exchange during strenuous exercise. When the surface area is decreased to one-third to one-fourth of normal, gas exchange is inadequate under resting conditions. Partial Pressure 1. The pressure exerted by a specific gas in a mixture of gases is reported as the partial pressure of that gas. 2. Oxygen diffuses from a higher partial pressure in the alveoli to a lower partial pressure in the pulmonary capillaries. Oxygen diffuses from a higher partial pressure in the tissue capillaries to a lower partial pressure in the tissue spaces. 3. Carbon dioxide diffuses from a higher partial pressure in the tissues to a lower partial pressure in the tissue capillaries. Carbon dioxide diffuses from a higher partial pressure in the pulmonary capillaries to a lower partial pressure in the alveoli. Oxygen diffuses from a higher partial pressure in the alveoli to a lower partial pressure in the pulmonary capillaries. Oxygen diffuses from a higher partial pressure in the tissue capillaries to a lower partial pressure in the tissue spaces. Carbon dioxide diffuses from a higher partial pressure in the tissues to a lower partial pressure in the tissue capillaries. Carbon dioxide diffuses from a higher partial pressure in the pulmonary capillaries to a lower partial pressure in the alveoli. Most (98.5%) O2 is transported bound to hemoglobin. Some (1.5%) O2 is transported dissolved in plasma. Oxygen is released from hemoglobin in tissues when the partial pressure for O2is low, the

©

Biofacultymember2020

NUR11O1 Integrated Human Anatomy and Physiology Department of Biology Institute of Arts and Sciences Far Eastern University

partial pressure for CO2 low, and temperature is high. Carbon Dioxide Transport and Blood pH 1. Carbon dioxide is transported in solution as plasma (7%), in combination with blood proteins (23%), and as bicarbonate ions (70%). 2. In tissue capillaries, CO2 3. In lung capillaries, HCO3 4. As blood CO2 cells to form carbonic acid that dissociates to form HCO3 This reaction promotes the transport of CO2. − combines with H+ The carbonic acid dissociates to form CO2 red blood cells levels and pH to form carbonic acid. , which diffuses out of the levels increase, blood pH decreases; as blood CO2 levels decrease, blood pH increases. Changes in breathing change blood CO2, levels and ph 15.06A. Describe the respiratory areas of Respiratory Areas in the Brainstem the brainstem and how they produce a 1. The medullary respiratory center, rhythmic pattern of ventilation. specifically the pre-Bötzinger complex, establishes rhythmic breathing. 2. The pontine respiratory group appears to be involved with the switch between inspiration and expiration. 15.06B. Name the neural mechanisms that Involuntary respiration is under can modify the normal rhythmic pattern subconscious of ventilation. control. The diaphragm and intercostal muscles, the primary respiratory muscles, are stimulated by groups of neurons located in the pons and medulla. These neurons form the respiratory control centre. They send impulses to the primary respiratory muscles, via the phrenic and intercostal nerves, which stimulates their contraction. Voluntary respiration is

©

Biofacultymember2020

NUR11O1 Integrated Human Anatomy and Physiology Department of Biology Institute of Arts and Sciences Far Eastern University

15.06C. Explain how blood pH, CO2, and O2 levels affect ventilation.

under conscious control. It is controlled via the motor cortex in the cerebrum, which receives inputs from the limbic system and hypothalamus. The mechanisms involved aren’t completely understood, but signals are thought to be sent to the spinal cord from the motor cortex, which are then passed onto the respiratory muscles. Oxygen levels are important because if they're low, hypoxia can occur. It stimulates chemorecptors in carotid artery and aortic bodies to stimulate breathing.

If blood CO2 increases, blood pH will decrease. Chemoreceptor in the medula oblongata will detect the increased CO2 levels and command a faster breathing rate. When breathing rate goes up, more CO2 will diffuse out and blood pH will increase. 15.07A. Describe the regulation of 1. Medullary Respiratory Center ventilation during exercise and the constantly receives stimulation from changes in the respiratory system that many sources. result from exercise training. 2. When input from these sources reaches a certain threshold, respiratory muscle produces action potential to being INSPIRATION. 3. Once inspiration begins, more and more neurons are activated (last about 2s). 4. When neurons responsible for stopping inspiration receive input (past a certain threshold), inspiration stops,muscles relax, and step 1 begins. Exercise causes Immediate increase to 50% or more of total breathing capacity, then gradual increase for another 4-6 minutes until plateauing. Training helps brain learn to match

©

Biofacultymember2020

NUR11O1 Integrated Human Anatomy and Physiology Department of Biology Institute of Arts and Sciences Far Eastern University

15.08A. Describe the effects of aging on the respiratory system.

breathing with intensity of exercise, so that the respiratory muscles move more efficiently. It also increases vital capacity, and decreases residual volume slightly. 1. Vital capacity and maximum minute ventilation decrease with age because of weakening of the respiratory muscles and stiffening of the thoracic cage. 2. Residual volume and dead space increase because the diameter of respiratory passageways increases. 3. An increase in resting tidal volume compensates for increased dead space, loss of alveolar walls (surface area), and thickening of alveolar walls. 4. The ability to remove mucus from the respiratory passageways decreases with age.

III. CONCLUSION: Make general statement (Maximum of three sentences on what you have learned on this activity. I have learned that the respiratory is actually very complex and involves a lot of balance in function as well. I realized all the more that we should take care and be aware of what our actions do to it.

©

Biofacultymember2020