Respiration Respiration l Physiological process by which oxygen
Respiration Ø Respiration l Physiological process by which oxygen moves into an animal’s internal environment and carbon dioxide moves out Ø Aerobic respiration l l l Cellular process, produces ATP Oxygen is used Carbon dioxide is produced
Respiratory System Ø Works with the circulatory system to deliver oxygen and remove carbon dioxide Ø Also helps regulate acid-base balance
Pressure Gradients Ø Concentration gradients for gases Ø Gases diffuse down their pressure gradients Ø Gases enter and leave the body by diffusing down pressure gradients across respiratory membranes
Factors In Gas Exchange Ø Surface-to-volume ratio l Small, flat animals Ø Ventilation l Adaptations enhance exchange rate Ø Respiratory pigments l Hemoglobin and myoglobin
Surface-to-Volume Ratio Ø As animal size increases, surface-to- volume ratio decreases Ø Small, flat animals can use the body surface as their respiratory surface Ø Larger animals have special structures to increase respiratory surface, such as gills or lungs
The main function of the respiratory system is _____. gas exchange 2. breathing 3. energy production 4. transportation of oxygen to tissues 1.
Respiratory Surfaces Ø In flat animals CO 2
Respiration Ø Respiration l Physiological process by which oxygen moves into an animal’s internal environment and carbon dioxide moves out Ø Aerobic respiration l l l Cellular process, produces ATP Oxygen is used Carbon dioxide is produced
Respiratory System Ø Works with the circulatory system to deliver oxygen and remove carbon dioxide Ø Also helps regulate acid-base balance
Pressure Gradients Ø Concentration gradients for gases Ø Gases diffuse down their pressure gradients Ø Gases enter and leave the body by diffusing down pressure gradients across respiratory membranes
Factors In Gas Exchange Ø Surface-to-volume ratio l Small, flat animals Ø Ventilation l Adaptations enhance exchange rate Ø Respiratory pigments l Hemoglobin and myoglobin
Surface-to-Volume Ratio Ø As animal size increases, surface-to- volume ratio decreases Ø Small, flat animals can use the body surface as their respiratory surface Ø Larger animals have special structures to increase respiratory surface, such as gills or lungs
The main function of the respiratory system is _____. gas exchange 2. breathing 3. energy production 4. transportation of oxygen to tissues 1.
Respiratory Surfaces Ø In flat animals CO 2
In the respiratory cycle, the main muscles used are the _____. intercostal and diaphragm 2. pharynx and larynx 3. bronchiole and alveoli 4. oral and pleural 1.
Fish Gills Ø Usually internal Ø Water is drawn in through mouth and passed over gills water flows in through mouth FISH GILL water flows over gills, then out
FISH GILL water flows into mouth a mouth closed mouth open water flows over gills, then out. lid open lid closed b c respiratory surface gill arch gill filament direction of water flow d e oxygenated blood back toward body direction of blood flow oxygen-poor blood from deep in body Fig. 22 -18, p. 372
Countercurrent Flow Ø Ø Blood flows in the opposite direction of water flow over the filaments Enhances movement of oxygen from water to blood respiratory surface direction of water flow oxygenated blood back toward body direction of blood flow oxygen-poor blood from deep in body
Vertebrate Lungs Ø Originated in some fishes as outpouching from gut wall Ø Allow gas exchange in air and in oxygenpoor aquatic habitats salamander reptile
Avian Respiration Ø Lungs are inelastic and connect to a series of air sacs Ø Air is drawn continually though each lung air sacs lungs air sacs
Mammals Mammal Human; adapted to dry habitats Fig. 22 -20 c, p. 373
Lungs are the only respiratory organs in all of the following animals, except _____. 1. 2. 3. 4. reptiles birds mammals amphibians
In addition to gas exchange, the respiratory system also _____. helps blood in veins return to the heart 2. helps dispose of excess heat and water 3. helps maintain acidbase balance 4. all of the choices 1.
Human Respiratory System pharynx (throat) epiglottis larynx (voice box) trachea (windpipe) pleural membrane Bronchiole Alveoli intercostal muscle diaphragm
NASAL CAVITY ORAL CAVITY (MOUTH) PHARYNX (THROAT) EPIGLOTTIS LARYNX (VOICE BOX) PLEURAL MEMBRANE INTERCOSTAL MUSCLES TRACHEA (WINDPIPE) LUNG (ONE OF A PAIR) BRONCHIAL TREE DIAPHRAGM Fig. 22 -21 a, p. 374
bronchiole alveolar sac (sectioned) alveolar duct alveoli Fig. 22 -21 b, p. 374
alveolar sac pulmonary capillary Fig. 22 -21 c, p. 374
Speech Production Ø Vocal cords stretch across laryngeal opening; opening between them is glottis Ø Position of cords is varied to create different sounds
vocal cords glottis (closed) epiglottis tongue’s base Fig. 22 -22 a, p. 375
glottis closed glottis open Fig. 22 -22 b, p. 375
Breathing Ø Moves air into and out of lungs Ø Occurs in a cyclic pattern called the respiratory cycle Ø One respiratory cycle consists of inhalation and exhalation
Inhalation Diaphragm flattens Ø External intercostal muscles contract Ø Volume of thoracic cavity increases Ø Lungs expand Ø Air flows down pressure gradient into lungs Ø
Normal (Passive) Exhalation Muscles of inhalation relax Ø Thoracic cavity recoils Ø Lung volume decreases Ø Air flows down pressure gradient and out of lungs Ø
INWARD BULK FLOW OF AIR b Inhalation. The diaphragm contracts, moves down. External intercostal muscles contract and lift rib cage upward and outward. The lung volume expands. OUTWARD BULK FLOW OF AIR c Exhalation. Diaphragm, external intercostal muscles return to resting positions. Rib cage moves down. Lungs recoil Fig. passively. 22 -23, p. 376
Active Exhalation Ø Abdominal and internal intercostal muscles contract Ø Contraction decreases thoracic cavity volume more than passive exhalation Ø Greater volume of air flows out to equalize intrapulmonary pressure with atmospheric pressure
In the respiratory cycle, the main muscles used are the _____. intercostal and diaphragm 2. pharynx and larynx 3. bronchiole and alveoli 4. oral and pleural 1.
Cutaway View of Alveolus red blood cell air space inside alveolus (see next slide) pore for airflow between alveoli
Respiratory Membrane Ø Area between an alveolus and a pulmonary capillary alveolar epithelium capillary endothelium Ø Oxygen and carbon dioxide diffuse across easily fused basement membranes of both epithelial tissues
Oxygen Transport Ø Most oxygen is bound to heme groups in hemoglobin in red blood cells Ø Hemoglobin has higher affinity for oxygen when it is at high partial pressure (in pulmonary capillaries) Ø Lower affinity for oxygen in tissues, where partial pressure is low
Bicarbonate Formation CO 2 + H 2 O H 2 CO 3 carbonic acid HCO 3– + H+ bicarbonate • Most carbon dioxide is transported as bicarbonate • Some binds to hemoglobin • Small amount dissolves in plasma
Control of Breathing Ø Nervous system controls rhythm and magnitude of breathing Ø Breathing is adjusted as a result of changes in l l l Carbon dioxide levels Oxygen levels Blood acidity
Oxygen that enters the pulmonary capillaries of the lungs is bound and transported by _____. 1. 2. 3. 4. hemoglobin platelets plasma carbon dioxide
Bronchitis Ø Irritation of the ciliated epithelium that lines bronchiole walls Ø Caused by air pollutants, smoking, or allergies Ø Excess mucus causes coughing, can harbor bacteria Ø Chronic bronchitis scars and constricts airways
Emphysema Ø Irreversible breakdown of lung tissue Ø Lungs become inelastic Ø May be caused by a genetic defect Ø Most often caused by smoking
Emphysema
Effects of Smoking Shortened life expectancy Ø Increased rate of cancers Ø Increased rate of heart disease Ø Impaired immune function and healing Ø Harmful to fetus Ø
Smokers increase their risk of _____. 1. 2. 3. 4. heart attack stroke breast cancer all of the choices
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