Biology, 9th ed, Sylvia Mader Chapter 37 Chapter 37 Respiratory Systems Respiratory Systems

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

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

For diffusion to be effective, gas-exchange regions must be: 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)

Gasses of air can dissolve in water However Water Environments Gasses of air can dissolve in water However When saturated, water contains small fraction of the O2 in same volume of air, and Water is much more viscous than air Aquatic animals expend more energy to breathe than do terrestrial animals

Larger aquatic animals 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

Animal Shapes and Gas Exchange

Anatomy of Gills in Bony Fishes

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

Tracheae of Insects

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

Ventilation in Frogs

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

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

Respiratory System in Birds

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%

The Human Respiratory Tract

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

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

Humans breathe using a tidal mechanism Ventilation 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

Inspiration Versus Expiration

Inhaling and exhaling- again with the physics and chemistry

External and Internal respiration

Hemoglobin

Gas Exchange and Transport Breathing stimulus Increased H+ and CO2 concentrations in the blood Not affected by O2 levels Oxygen diffuses into pulmonary capillaries Most combines with hemoglobin in red blood cells to form oxyhemoglobin CO2 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

Hemoglobin Saturation in Relation to Temperature and Acidity

Carbon dioxide focus: tissue to blood STEPS:

Carbon dioxide: blood to lungs STEPS:

Explain this

Respiration and Health Upper Respiratory Tract Infections Strep Throat Streptococcus pyogenes Sinusitis Infection of sinuses Tonsillitis Infection of tonsils Laryngitis Infection of larynx

Common Bronchial and Pulmonary Diseases

Respiration and Health Lower Respiratory Tract Infections Acute bronchitis Infection of primary and secondary bronchi Pneumonia Viral or bacterial infection of the lungs where bronchi and alveoli fill with fluid Pulmonary tuberculosis Caused by tubercle bacillus

Disorders Pulmonary fibrosis Chronic bronchitis Emphysema Fibrous connective tissue builds up in the lungs Chronic bronchitis Airways inflamed and filled with mucus Emphysema Alveoli are distended and walls are damaged reducing surface area available for gas exchange

Disorders Asthma Lung Cancer Airways are unusually sensitive to specific irritants When exposed to the irritants, the smooth muscles in the bronchioles undergo spasms Lung Cancer Begins with thickening and callusing of the cells lining the airways

Human Respiratory System Review Gas Exchange Surfaces Water Environments Gills Land Environments Lungs Human Respiratory System Inspiration versus Expiration Respiration and Health Respiratory Disorders

Biology, 9th ed, Sylvia Mader Chapter 37 Ending Slide Chapter 37 Respiratory Systems Respiratory Systems