Chapter 5- Flight Muscles and Skeleton (133-140)

Bio 317 Test #3 Review

Chapter 5- Flight muscles and skeleton (133-140) Light weight, reduction in number of elements, fusion, rigidity Core of body is rigid fulcrum against which the appendages act Fused thoracic vertebrae, tightly interlocked cervical vertebrae Braced ribs- uncinate processes Pectoral girdle- Separate coracoids, furcula, scapula, and keeled sternum Furcula/fused clavicles articulate with lateral ends of coracoids Sharp/acute angles between coracoids, scapula, humerus- large mechanical advantage Foramen triossum and supracoracoideus tendon Pectoralis contraction for downstroke, Supracoracoideus and Dorsal Elevator for upstroke Furcula- Lateral ends are compressed during upstroke (Box 5-3, Fig 5-16) Elastic recoil contributes to downstroke + ventilation Negative pressure for inhalation (no diaphragm) Forelimb anatomy- fusion of bones, especially in the hands and fingers (carpometacarpus) Dark and light muscles, endurance vs quick power, mixed fibers,…

Chapter 6- Physiology (pages 141-164) Mobility, power, and endurance require extreme metabolism, body temp, water use, waste processing,… High efficiency, light weight digestion, ventilation, gas exchange, thermoregulation, excretion, repro,…

Body Temperature Higher than in mammals (42 degrees Celsius vs 37 degrees Celsius)- Pros and Cons Pros- Increased power, energy production, metabolic rate, nerve transmission rates Cons- Increased food requirements, gas exchange requirements, waste production, fatal 46 degree limit

High metabolism and body temperature “problem” (body volume and body surface area) 46 degree limit, high heat production, no sweat glands, need to minimize evaporative cooling during exhalation Features that increase thermoregulatory efficiencies “Fresh” winter/basic plumage provides increased insulation, denser growth in cooler climates Acclimitization in ptarmigan and goldfinches- reduce met rate to reduce heat loss Toucan’s bill Salt marsh sparrows- heat regulation, water balance, “extra” functions and bill morphology

Night time “problem”- maintaining high metabolism during long periods of inactivity, starvation Nocturnal/Facultative hypothermia (heterothermy)- drop body temp, drop Oxygen consumption Very important for pre-migratory fattening Torpor and avian hibernation

Respiratory System Key constraints- huge demands but small overall size, no diaphragm Key features- one-way flow, cross current gas exchange, upstroke contributes to exhalation, downstroke contributes to inhalation, furcula, hairpin turn leading to anterior air sac 2 cycle ventilation (Figs 6-5 and 6-6) Accessory functions of air sacs- sound production, visual display, heat removal Hyperventilation- how do bird brains tolerate high pH?

Circulatory System Key features- double circulation, extra large heart, fast rhythm, high output, high pressure,…