GENERAL AND COMPARATIVE ANIMAL PHYSIOLOGY By Akrum Hamdy

GENERAL AND COMPARATIVE ANIMAL PHYSIOLOGY • By • Akrum Hamdy

I. General Introduction. II. Definition of Life I. All life must be capable of reproduction of their unique structure & function, be able to metabolize and adapt to their surrounding environment long enough to reproduce, and have the ability to evolve (slight structural and functional changes through generations of life) Life on this planet is based on 4 basic chemicals, Carbohydrates, lipids, proteins and nucleic acids. II. All life could have started spontaneously from the Primordial soup and atmosphere of the primitive earth.

A. Internal vs External Environments 1. Homeostasis 2. The cellular environment Physiological Adaptations for 1. Aerial Environments 2. Aquatic environments 3. Terrestrial environments B. Acclimation vs. Acclimatization 1. Definitions 2. Adaptation 3. Contrast of physiological approaches to adaptation

D. a. Regulator b. Conformer Animal Fitness 1. Survival tests and physiological limits 2. Population environmental limits (reproduction) II. Respiration, oxygen, carbon dioxide, & exchange.

2. Effects of altitude and pressure on respiration A comparison of aerial and aquatic respiration procurement of O 2 from the environment. A. Animals without specialized organs B. Specialized Respiratory organs basic design and function 1. tracheal systems 2. gills - a respiratory examination 3. lungs - a respiratory invigilation 4. skin

A. Basic physical gas laws 1. Ideal gas law (P x V = n x R x T) 2. Daltons law of partial pressures (Pt = P 1 + P 2 + Px) 3. Solubility of gases in water (Henry's law) V = a x. P 4. Diffusion of gases in water and air. Composition of the atmosphere 1. Effects of water vapor on gas mixture and respiration

• C. Aquatic respiration and gills – 1. • a. • b. • c. irrigation vs. ventilation comparison of medium viscosity and movement of medium over the gill or movement of gill over the medium. A comparison of the energy cost, mechanical damage, effect of medium influence on gas exchange, dry vs. wet environment, Effects of temperature, salinity, ion content other chemicals on gas exchange

b. other gill functions 1) osmotic and ionic regulation 2) waste removal 2. Basic structure and function of gills a. enclosed in chamber for protection and flow pattern b. counter current effect c. arches, filaments, & lamella d. crab gills D. Respiration in Air, Lungs, skin, & tracheal systems. 1. gills and air respiration 2. (exceptions) 2. Use of skin 3. Other respiratory organ

During the summer Frog lungs become a more important source of O 2 because in the higher summer temps the MR is increased.

Toad skin and lung can vary with respect to the uptake and release of O 2 and CO 2 depending on the temperature At 5 C the skin is more important than lung for O 2. The same is true for CO 2 release

Birds can fly at high altitudes because their one way flow through lung is more efficient at extracting O 2 from the air. Tidal flow in mammalian lung is not as efficient.

For air to move completely through the avian respiratory system of air sacs and rigid one way flow lungs there must be 2 complete respiratory cycles.

Sea Cucumbers are the only marine invertebrate with a true tidal lung that suctions water in and then pushes it back out the same aperature (Anus) What would you predict about the metabolic rate and activity level of these animals from their lung structure and function?

Invertebrates have complex respiratory systems including, gills and diffusion lungs.

External gills can be a liability. It is interesting to note that at the base of many polychaete worms are parapodia that can be specialized to “bite or clamp down” on anything that tries to damage or “eat these fine gill filaments

The egg shell and membranes serve as the exchange barriers and surface for embryos the are placed in them. Pore size and number become important factors in respiration

Lung volumes are constant relative to body size and are about 5 – 7 % of total body mass. Allometry is an important tool for comparing different sized animals and the proportion of their body devoted to an organ or tissue.

Blood Pigments help to Transport respiratory gas. The evolution of these pigment arose as organisms became larger and more complex and also as they moved from a aquatic environment onto the land.

– A. Respiratory pigments – 1. Comparison of 4 principle blood pigments • a. – – – b. Hemoglobin (erythrocurin) 1) 2) 3) Structure (allosteric effects) Distribution Bohr effect & Reverse Bohr effect 4) Root effect 5) Temperature 6) 2 -3 DPG pigment enhancers Chlorocrourin – 1) structure – 2) distribution – 3) other

Blood Pigments Continued • c. Hemerythrin – 1) structure – 2) distribution – 3) other • d. Hemocyanin – 1) structure – 2) distribution – 3) other

– 2. • a. • b. • c. Intracellular pigments myoglobin cytochromes chlorophyll

B. Role of respiratory pigments in different environments 1. High P O 2 - low affinity pigments –example: Terrestrial mammals: lots of easily accessible O 2 in normal air, no need for thigh protective diffusion barrier because no ionic problems in gas exchange in air, low affinity pigment allows for easier & greater unloading at cells/tissues and permits high O 2 use, easier delivery Another example is in marine environments where polychaetes like Sabella have chlorocrourin and the pigment acts as an emergency store and increases the blood O 2 carrying capacity 2. High P O 2 - High affinity pigment i. e. decapod crustaceans like Spiny lobster from the marine environment have basic problems with ionic/osmotic balance in marine environment. Need a high affinity pigment to pick up O 2 across thick gill diffusion barrier that is designed to help control water loss and ion influx from sea water. High affinity needed to facilitate O 2 uptake across thick gill barrier. Unloads only at

3. Low P O 2 - High affinity pigment found in invertebrates that move from high O 2 to areas of low O 2 regularly. Inverts living in fluctuating environments like local lakes where O 2 in water can be quite high but the animals then travel into anaerobic mudflats where the pigment then serves as an O 2 reserve during emergency. Under normal circumstances O 2 bound to pigment is not used. Another i. e. is planorbis (pulmonate snail) uses high affinity pigment to allow for longer dives under water were O 2 is low and will ventilate lung chamber before and after dive where air is stored and pigment can procure O 2 during dive. 4. Low P O 2 - Low affinity pigment i. e. Sipunculid worms (peanut worms) like Siphonosoma ingest that lives in a marine sediment burrow. Has interesting circulatory system where blood cells contain heme-erythrin in thick walled tentacles that emerge from burrow. Harsh water/ion gradients in marine water but they have a low affinity pigment in tentacles. In body cavity have a high affinity coelomic pigment that facilitates

Control of Respiration is it O 2 or CO 2 that is more important?

Control of Respiration • Respiratory control center in brain: a reverberating circuit. • Primary pacemakers are inspiratory center found in the pones & medulla of higher vertebrates • Send impulses to Diaphragm or muscles of inspiration via phoenix nerve • Also send impulses to agnostic or expiratory center and stimulate them to eventually fire and turn off pacemaker cells

Why is CO 2 more important? • Henderson – Hassle Bach equation • CO 2 + H 20 ----- H 2 CO 3 - HCO 3 + H • This reaction is sped up by Carbonic Anhydrate found in Erythrocyte membranes • p. H Blood = 6. 1 x log 10 of [HCO 3]/[H 2 CO 3] •

Air Bladder rate for O 2