Pop Quiz What produces mucus, HCl and pepsinogen in the stomach? List a water soluable vitamin What is a ruminant stomach?
Respiratory System
Review Cellular respiration: obtain glucose and oxygen, get rid of wastes and carbon dioxide
Review Cellular respiration: Exchange occurs in the mitochondria
Gas exchange: breathing, gas transport, servicing cells
Gas exchange Breathing involves inhaling O 2 and exhaling CO 2 Transport involves diffusion, hemoglobin, and occurs in RBC s Blood supplies every cell with O 2 and picks up waste CO 2
CO 2 and O 2 are exchanged over moist body surfaces
CO 2 and O 2 are exchanged over moist body surfaces Surfaces must be thin and extensive Gasses dissolve in water before the diffuse in or out of cells Fish have gills that project from the body, worms exchange across the skin, insects have trachea, terrestrial vertebrates have lungs
Gills achieve gas exchange in aquatic environments
Gills achieve Gas exchange in aquatic environments
Gills Advantage: - Gills are always wet Disadvantage:O 2 is less abundant in water Inhale - close opercula and expand mouth; exhale open opercula and flush water over the gills with the mouth closed Gas is exchanged across the gill filaments and lamellae then into capillaries
Countercurrent exchange
Countercurrent exchange
Countercurrent exchange Found in many animal systems thermoregulation, and in the kidney The transfer of a substance flowing in one direction to another moving in the opposite direction Efficient - gill can remove 80 % of O 2
Insect tracheal system
Insect tracheal system Air contains more O 2 than water, air is easier to move,terrestrial vertebrates use less energy in ventilating their respiratory surfaces Tracheae branch extensively, bringing air directly to cells Air sacs pumped by muscles move air in and out
Insect tracheal system System consists of: Spiracles (openings) Tracheae (branched tubes) Tracheoles (fluid filled and reach all cells) Airsacs (enlarged chambers that work like bellows)
Terrestrial vertebrates: lungs
Figure 42.23c Alveoli
Terrestrial vertebrates: lungs Restricted to one part of the body, circulatory system required to transport gasses to/from the cells Human respiratory system: Nasal cavity (filters, warms, humidifies an d senses odors) Pharynx (conducts air and food) Larynx/ vocal cords (muscular cords which can be tensed or stretched to generate sound as air rushes by) Trachea (windpipe)
Terrestrial vertebrates: lungs Lungs Bronchi (forked tubes leading to the lungs) Bronchioles (smallest tubes leading to the alveoli- site of gas exchange) Diaphragm (muscular, moves air in/out of lungs) Breathing
Normal function: Smoking and lung function Mucus and cilia trap and move pollutants and sweep them out of the respiratory system Macrophages kill bacteria Tobacco smoke irritates epithelial cells Destroys cilia and macrophages Toxins reach the alveoli, coughing results Emphysema - brittle alveoli that eventually rupture Smoking leads to cardiovascular disease
Respiratory diseases Upper respiratory system infection - viral infection - inflammation of mucus membranes. Lung Cancer Linked to smoking. Pneumonia Viruses, fungi or bacteria in the alveoli. Fluid in the lungs prevents gas exchange there. Tuberculosis Caused bytubercle bacilli Symptoms: cough fever weight loss infection. Nodules and scars form preventing normal alveoli function. Pulmonary embolism
Breathing fig 22.8A
Breathing ventilates the lungs Inhalation Ribcage expands, diaphragm contracts, chest expands - lungs increase in size - air flows into the alveoli from higher pressure outside. Exhalation Rib and diaphragm muscles relax- chest contracts, lungs decrease in size -air forced out.
Birds have highly efficient, flow through lungs (fig 22.8B)
Birds have highly efficient, flow through lungs One - way air flow through the lungs Air sacs ventilate respiratory surface in the lungs Inhalation- posterior sacs fill with fresh airanterior sacs fill with stale air Exhalation - both sacs deflate forcing air into the lungs and out of the system No alveoli, parallel tubes, countercurrent exchanger, 5% more efficient than mammalian lung
Control over breathing CO 2 Carbonic acid Lowered blood ph Medulla increases respiratory rate
Control over breathing Autonomic control centers in the brain regulate breathing It ensures coordination between the circulatory and respiratory systems Breathing control centers monitor ph, CO 2, and remote sensors monitor O 2 in the blood. Control centers signal rib muscles and diaphragm to alter breathing rate CO 2 is the major signal controlling the respiratory rate
Transport of gases in the body
Transport of gases in the body Blood transports the respiratory gases, hemoglobin carries the oxygen Heart has 2 pumps One pumps O 2 poor blood to the lungs One pumps O 2 rich blood to the body O 2 dissolves poorly in fluids, hemoglobin in RBC s increases ability of cells to carry O 2
Hemoglobin
Hemoglobin Transports both O 2 and CO 2 Helps to buffer the blood by carrying CO 2 HCO 3- generated can bind H + and keep blood ph stable Reverse process occurs in the lung, so CO 2 is given off
Hemoglobin A multipurpose molecule Transports oxygen Transports carbon dioxide Buffers the blood Tissue cells- forms carbonic acid, bicarbonate, and H+ Lungs - the reverse reaction occurs - off loading carbon dioxide to the alveoli
Fetal respiration
Fetal respiration Fetus is in the amniotic fluid Capillaries from the fetus (umbilical cord) and the uterus combine to form the placenta Countercurrent exchange occurs between the capillaries of the fetus and the mother Fetal hemoglobin attracts O 2 better than maternal hemoglobin Placental transfer stops at birth - the umbilical cord is cut - respiratory center is stimulated from decreased blood ph
Pop Quiz! Write the chemical reaction for generating bicarbonate from carbon dioxide State one reason that a bird lung is more efficient than a mammalian lung
Review Cellular respiration vs. breathing Respiratory surfaces Lungs, gills, bird lungs, epithelial exchange Respiratory illnesses Anatomy of the system Transport of gases Fetal circulation