Identify the structures of the lower respiratory system and provide their function. 3. Explain how the alveoli increase the efficiency of the respiratory system. 9. 4 Mechanism of Breathing 1 . Contrast the processes of inspiration and expiration during ventilation. 2. Define the terms tidal volume, vital capacity, and residual volume in relation to ventilation. 3. Summarize the purpose of the inspiratory and expiratory reserve volumes. 9. 5 Control of Ventilation 1. Explain how the nervous system controls the process of breathing. 2. Explain the role of chemoreceptors and pH levels in regulating breathing rate. 9.
Gas Exchanges in the Body 1. Distinguish between external and internal respiration. 2. Summarize the chemical processes that are involved in external and internal respiration. 3. Identify the role of carbonic anhydrase and carbaminohemoglobin in respiration. 9. 7 Respiration and Health 1. Identify the symptoms and causes of selected upper respiratory tract infections. 2. Identify the symptoms and causes of selected lower respiratory tract disorders. 3. Summarize the relationship between smoking, cancer, and emphysema. LECTURE OUTLINE The organs of the respiratory system ensure that oxygen enters the body and carbon ioxide leaves the body.
Ventilation is another term for breathing that includes both inspiration or inhalation and expiration or exhalation. 9. 2 The Upper Respiratory Tract The nasal cavities, pharynx, and larynx are the organs of the upper respiratory tract. The Nose The two nasal cavities, which contain receptor cells, receive tear ducts from eyes and communicate with sinuses. The auditory tube from middle ear communicates with the nasopharynx. The nose warms and cleanses incoming air. The pharynx, a passageway from the nasal cavities to oral cavities, and to the larynx, contains the tonsils.
The pharynx takes air from the nose to the larynx and transports food from the oral cavity to the esophagus. The Larynx The epiglottis covers the glottis, an opening to the larynx which contains vocal cords. The trachea and the rest of the respiratory system are in the lower respiratory tract. The Trachea The trachea, supported by C-shaped cartilaginous rings, is lined by ciliated cells which sweep impurities up to the throat. The trachea takes air to the bronchial tree. The Bronchial Tree Two primary bronchi, which divide into ever smaller bronchioles, conduct air into and within the lungs.
During an asthma attack, bronchioles constrict. The Lungs The lungs are paired, cone-shaped organs within the thoracic cavity. The right lung has three lobes, while the left has two lobes. The Alveoli The alveoli are the air sacs lined by squamous epithelium and surrounded by blood capillaries. Alveoli function in gas exchange. Premature infants often suffer from respiratory distress syndrome. 9. 4 Mechanism of Breathing Ventilation or breathing has two phases: inspiration which moves air into the lungs and expiration which moves air out of the lungs.
Inspiration During inspiration, the diaphragm and external intercostal muscles contract, ncreasing the volume of the thoracic cavity. This causes air to move into the lungs. Humans inhale by negative pressure. Expiration Expiration is the passive phase of breathing. The elastic properties of the thoracic wall and lungs cause them to recoil, moving air out. Maximum Inspiratory Effort and Forced Expiration Maximum inspiratory effort involves muscles of the back, chest, and neck, which increases the size of the thoracic cavity larger than normal. Although expiration is normally passive, it can also be forced.
This is necessary to sing and blow out air. Volumes of Air Exchanged During Ventilation A spirometer is used to measure the amount of air that is moving into and out of the lungs. Tidal Volume The tidal volume, only about 500 mL, is the small amount of air that moves in and out with each breath when we are relaxed. Vital Capacity The maximum amount of air that can be moved in plus the maximum amount that can be moved out during a single breath is called the vital capacity. Inspiratory and Expiratory Reserve Volume Residual Volume Some air always remains in the lungs.
This is the residual volume and is no longer useful for gas exchange. 9. 5 Control of Ventilation Nervous Control of Breathing Normally adults have a breathing rate of 12 to 20 ventilations per minute. This rhythm is controlled by a respiratory control center located in the medulla oblongata of the brain. It is thought that a faulty respiratory center signal is the cause of sudden infant death syndrome (SIDS). We can voluntarily change our breathing pattern to accommodate various activities. Chemical Control of Breathing Chemoreceptors are sensory receptors in the body that are sensitive to chemical composition of body fluids.
The pH of blood will become more acidic when there is ore carbon dioxide in the blood. Two sets of chemoreceptors that are sensitive to pH can cause breathing to speed up. 9. 6 Gas Exchanges in the Body Gas exchange is critical to homeostasis. The principles of diffusion govern whether oxygen or carbon dioxide enters or leaves the blood in the lungs and in the tissues. External Respiration External respiration is the diffusion of C02 from pulmonary capillaries into alveolar sacs and 02 from alveolar sacs into pulmonary capillaries. Internal Respiration Internal respiration is the diffusion of 02 from systemic capillaries into tissues and
C02 from tissue fluid into systemic capillaries. 9. 7 Respiration and Health The respiratory tract is constantly exposed to environmental air and therefore to pathogens. Upper Respiratory Tract Infections Upper respiratory tract infections include the following: Sinusitis Infection of cranial sinuses Otitis Media Infection of the middle ear Tonsillitis Infection of tonsils Laryngitis Infection of larynx Lower Respiratory Tract Disorders Lower respiratory tract disorders include infections, restrictive and obstructive pulmonary disorders, and lung cancer. Lower Respiratory Infections
Lower respiratory infections include acute bronchitis (infection of primary and secondary bronchi), pneumonia (infection of lungs), and pulmonary tuberculosis (infection caused by tubercle bacillus). Restrictive pulmonary disorders involve a reduction of vital capacity and can be caused by, for example, asbestos. Obstructive Pulmonary Disorders Obstructive pulmonary disorders includes chronic bronchitis (inflamed airways) and emphysema (alveolar walls break down). Asthma is a disease of the bronchi and bronchioles that is marked by an unusual sensitivity to specific irritants. Asthma is not curable but it is treatable.
Lung Cancer Lung cancer follows this sequence of events: thickening of airway cells, loss of cilia, atypical nuclei, tumor, and metastasis. Chapter 10 urinary system Homework 10. 1 The Urinary System 1. Identify the organs of the urinary system and state their function. 2. Summarize the functions of the urinary system. 10. 2 Kidney Structure 1. Identify the structures ofa human kidney. 2. Identify the structures ofa nephron and state the function of each. 10. 3 Urine Formation 1. Summarize the three processes involved in the formation of urine. 2. List the components of the glomerular filtrate. . Describe how tubular reabsorption processes nutrients and salt molecules. 4. Explain the substances that are removed from the blood by tubular secretion. 10. 4 Kidneys and Homeostasis the purpose of ADH, ANH, and aldosterone in homeostasis. 3. Explain how the kidneys assist in the maintenance of the pH levels of the blood. 10. 5 Kidney Function Disorders 1. List the major diseases of the urinary system and summarize their causes. 2. Describe how hemodialysis can help restore homeostasis of the blood in the event of kidney failure. Excretion is the removal of metabolic wastes from the body.
The kidneys are the rimary organs of excretion. Organs of the Urinary System Kidneys The kidneys are paired organs located near the small of the back, on either side of the vertebral column. The kidneys produce urine. Ureters The ureters conduct urine from the kidneys to the bladder. Peristaltic contractions cause urine to enter the bladder. Urinary Bladder The urinary bladder stores urine until it is expelled from the body through the urethra. The bladder wall is expandable. Urethra The urethra is a small tube that extends from the bladder to an external opening. The urethra has a different length in females than in males.
In males, the urethra carries urine during urination and sperm during ejaculation. Functions of the Urinary System The kidneys carry out functions that contribute to homeostasis. Excretion of Metabolic Wastes The kidneys remove metabolic waste which is absolutely necessary for maintaining homeostasis. Maintenance of Water-Salt Balance The kidneys regulate the water-salt balance which affects blood volume and blood pressure. Maintenance of Acid-Base Balance The kidneys can rid the body of a wide range of acidic and basic substances, so the kidneys have ultimate control over blood PH.
Secretion of Hormones The kidneys produce renin, an enzyme that leads to aldosterone secretion. The kidneys also secrete erythropoietin, which increases red blood cell synthesis. Additional Functions of the Kidneys The kidneys also reabsorb filtered nutrients and convert vitamin D. 10. 2 Kidney Structure Macroscopically, the kidneys are divided into the renal cortex, renal medulla, and Anatomy of a Nephron Each nephron has its own blood supply; the afferent arteriole approaches the glomerular capsule and divides to become the glomerulus, a capillary tuft.
The permeability of the glomerular capsule allows small molecules to enter the capsule rom the glomerulus. The efferent arteriole leaves the capsule and immediately branches into the peritubular capillary network. Parts of a Nephron Each region of the nephron is anatomically suited to its task in urine formation. The spaces between podocytes of the glomerular capsule allow small molecules to enter the capsule from the glomerulus, a capillary knot.
The cuboidal epithelial cells of the proximal convoluted tubule have many mitochondria and microvilli to carry out active transport (following passive transport) from the tubule to blood. In contrast, the uboidal epithelial cells of the distal convoluted tubule have numerous mitochondria but lack microvilli. They carry out active transport from the blood to the tubule. 10. 3 Urine Formation Glomerular Filtration During glomerular filtration, small molecules including water, wastes, and nutrients move from the glomerulus to the inside of the glomerular capsule.
Tubular Reabsorption During tubular reabsorption, nutrients and water move from the proximal convoluted tubule into the blood of the peritubular capillary network. Only those molecules recognized by carrier molecules are actively reabsorbed. The amount of a substance hat can be reabsorbed is limited by its number of carrier molecules. Tubular Secretion During tubular secretion, certain substances like hydrogen ions, creatinine, and penicillin move from the blood into the distal convoluted tubule. 10. 4 Kidneys and Homeostasis The kidneys play a major role in homeostasis.
Kidneys Excrete Waste Molecules The tubules of the kidney remove waste, especially nitrogenous wastes, from the body. Water-Salt Balance Most of the water found in the filtrate is reabsorbed into the blood before urine leaves the body. Reabsorption of Salt and Water from Cortical Portions of the Nephron Most of he water that enters the glomerular capsule is reabsorbed from the nephron into the blood at the proximal convoluted tubule. Na+ is actively reabsorbed, and Cl- follows passively. Hormones regulate the reabsorption of sodium and water in the distal convoluted tubule.
Reabsorption of Salt and Water from Medullary Portions of the Nephron The ability of humans to regulate the tonicity of their urine is dependent on the work of the medullary portions of the nephron and the collecting duct. The Loop of the Nephron Salt passively diffuses out of the lower portion of the ascending limb. Water leaves he descending limb along its entire length. Fluid within the collecting duct encounters the same osmotic gradient established by the ascending limb of the nephron. Therefore, water diffuses from the entire length of the collecting duct into the blood.
Interaction of Renin, Aldosterone, and ANH When blood Na+ concentration falls too low, blood pressure falls and the renin- aldosterone sequence begins. With increased blood volume, the atria of the heart are stretched, and this stretching triggers the release of ANH by the heart. Diuretics Diuretics are chemicals that increase the flow of urine. Acid-Base Balance of Body Fluids The normal pH for body fluids is between 7. 35 and 7. 45. If the blood pH rises above that, a person is said to have alkalosis.
If the blood pH decreases below that, a person is said to have acidosis. These are abnormal conditions that need medical attention. Acid-Base Buffer Systems The pH of the blood stays near 7. 4 because the blood is buffered. One of the most important buffers in the blood is a combination of carbonic acid and bicarbonate ions. Respiratory Center The respiratory center in the medulla oblongata increases the breathing rate if the ydrogen ion concentration of the blood rises. The Kidneys Only the kidneys can rid the body ofa wide range of acid and basic substances.
The kidneys are slower acting than the buffer systems and respiratory center, but they have a more powerful effect on PH. The Kidneys Assist Other Systems Aside from producing renin, the kidneys assist the endocrine system and also the cardiovascular system by producing erythropoietin. The kidneys convert vitamin D to its active form needed for calcium absorption by the digestive tract. 10. 5 Kidney Damage, especially recurring urinary infections, can lead to glomeruli that allow large olecules like proteins to be in the filtrate or glomeruli.
Hemodialysis The usual form of hemodialysis involves cleansing the patient''s blood by passing it through dialysis tubing in contact with a dialysis solution. Wastes and excess salts pass out of the tubing into the dialysis solution. In continuous ambulatory peritoneal dialysis (CAPD), the dialysis solution is introduced into the peritoneal cavity. Wastes filter from the blood into the solution which is removed 4 to 8 hours later. Replacing a Kidney When kidneys fail, kidney transplants can be successful, especially if the donor is a close relative.
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