Respiratory Systems Chapter 37

Respiratory Systems 2Outline Gas Exchange Surfaces  Water Environments ­Gills  Land Environments ­Lungs Human Respiratory System  Inspiration versus Expiration Respiration and Health  Respiratory Disorders

Respiratory Systems 3 Gas Exchange Surfaces Respiration:  The events associated with gas exchange between the cells and the external environment  Consists of ­Ventilation ­External Respiration ­Internal Respiration

Respiratory Systems 4 Gas Exchange Surfaces For diffusion to be effective, gas-exchange regions must be:  Moist  Thin  Relatively large Effectiveness of diffusion is enhanced by vascularization Delivery to cells is promoted by respiratory pigments (like hemoglobin)

Respiratory Systems 5 Water Environments Gasses of air can dissolve in water However  When saturated, water contains small fraction of the O 2 in same volume of air, and  Water is much more viscous than air  Aquatic animals expend more energy to breathe than do terrestrial animals

Respiratory Systems 6 Gas Exchange Hydras and planarians  Small animals with large surface area  Most of their cells exchange gases directly with the environment Larger aquatic animals  Often have gills ­Finely divided vascularized outgrowths of inner body surface ­Gills of bony fishes  Outward extensions of pharynx  Ventilation is brought about by combined action of the mouth and gill covers (operculum)  Countercurrent Exchange

7 Animal Shapes and Gas Exchange

8 Anatomy of Gills in Bony Fishes

Respiratory Systems 9 Land Environments: Tracheae Insects and other terrestrial arthropods  A respiratory system consists of branched tracheae  Oxygen enters tracheae at spiracles  Tracheae branch until end in tracheoles that are in direct contact with body cells

10 Tracheae of Insects

Respiratory Systems 11 Land Environments: Lungs of Vertebrates Terrestrial vertebrates have evolved lungs  Vascular outgrowths from lower pharyngeal region  Lungs of amphibians ­Possess a short tracheae which divides into two bronchi that open into lungs ­Many also breathe to some extent through skin  Reptiles ­Inner lining of lungs is more finely divided in reptiles than in amphibians  Lungs of birds and mammals are elaborately subdivided All terrestrial vertebrates, except birds, use a tidal ventilation system  Air moves in and out by the same route

12 Ventilation in Frogs

Respiratory Systems 13 Ventilation in Terrestrial Vertebrates Inspiration in mammals Create negative pressure in lungs  The rib cage is elevated  The diaphragm lowers  Thoracic pressure decreases to less than atmospheric pressure  Atmospheric pressure forces air into the lungs Expiration in mammals Create positive pressure in lungs  The rib cage is lowered  The diaphragm rises  Thoracic pressure increases to more than atmospheric pressure  Forces air out the lungs

Respiratory Systems 14Lungs Birds use a one-way ventilation mechanism in lungs  Results in a higher partial pressure of oxygen in the lungs  Oxygen uptake with each breath is greater than in other vertebrates

15 Respiratory System in Birds

Respiratory Systems 16 Human Respiratory System As air moves through upper respiratory system  It is filtered to free it of debris  Warmed, and  Humidified When air reaches lungs  It is at body temperature, and  Its humidity is 100%

17 The Human Respiratory Tract

Respiratory Systems 18 Human Respiratory System Air passes from pharynx through glottis Larynx and trachea  Permanently held open by cartilage rings  Facilitates movement of air When food is swallowed  The larynx rises, and  The glottis is closed by the epiglottis  Backward movement of soft palate covers the entrance of nasal passages into the pharynx

Respiratory Systems 19 Human Respiratory System Trachea divides  Forms two primary bronchi  Bronchi enter the right and left lungs Bronchi branch until there are a great number of tiny bronchioles  Each bronchiole terminates in an elongated space enclosed by alveoli

Respiratory Systems 20Ventilation Humans breathe using a tidal mechanism  Volume of thoracic cavity and lungs is increased by muscle contractions that lower the diaphragm and raise the ribs ­Create negative pressure in the thoracic cavity and lungs, and then air flows into the lungs during inspiration

21 Inspiration Versus Expiration

22 External and Internal respiration

External and Internal Respiration Detail 23

24 Hemoglobin

Respiratory Systems 25 Gas Exchange and Transport Breathing stimulus  Increased H + and CO 2 concentrations in the blood  Not affected by O 2 levels Oxygen diffuses into pulmonary capillaries  Most combines with hemoglobin in red blood cells to form oxyhemoglobin CO 2 diffuses out of pulmonary capillaries  Most carbon dioxide is transported in the form of bicarbonate ion  Some carbon dioxide combines with hemoglobin to form carbaminohemoglobin

26 Hemoglobin Saturation in Relation to Temperature and Acidity

27 Common Bronchial and Pulmonary Diseases

Respiratory Systems Ending Slide Chapter 37