Module 2

• Comparative animal physiology- animal to animal or animal to humans
• August Krogh principle- For every question about biology there is an ideal system to study it
• Types of physiology comparative- Mechanistic- evolutionary (obsolete)- environmental
• General themes in physiology- Structure & function relationships- Acclimation & adaptation- feedback & feedforward control systems- conformity & regulation or homeostasis
• Bears- shallow hibernation
• Structure & function relationship- How does the anatomy of an organ allow it to fulfil its physiological function
• Oxygen taking in efficiency- Fish gills > Bird lungs > Mammal lungs
• Acclimatisation- a physiological change caused by moderate to long term exposure to a given environmental condition- either naturally or in a laboratory setting- Short term, like getting used to low O2 mountain air
• Ruppell’s Griffin- fly insanely high- acclimatisation is used to get used to harder to fly attitudes
• Adaptation- physiological mechanisms that have developed over long periods of time (generations) due to constant exposure of a population to a given environmental condition
• Populations of people that are born & raised in high altitudes have hemoglobin that has a higher affinity for oxygen- Over generations
• Feedback & Feedforward- reaction to change to maintain homeostasis- Glucose in blood
• Maintaining homeostasis when excess glucose- Glucose rises- beta cells of pancreas are release insulin- Body takes up more glucose & liver takes it up and stores it as glycogen- insulin level drops as glucose levels drop- homeostasis is achieved- 90 mg/100mL
• Maintaining homeostasis when glucose deficit- glucose levels drop- stimulates alpha cells in pancreas to release glucagon in the blood- Glucagon signals the liver to breakdown glycogen & release it into blood- Glucose levels return to normal & glucagon stops production- homeostasis
• Most hormones have a negative feedback loop mechanism- they inhibit change
• Feedforward system- Proactive reactions to anticipated changes to maintain homeostasis- Insulin is actually released in response to (carbs) foods in the intestine- not as significant as feedback loops
• Islet of Langerhans in the pancreas secrete insulin- made up of alpha, beta & delta cells as well as capillaries
• Conformity- the typical internal level of any given variable does not differ from the environment
• Regulation- The typical internal level of any given variable that is different from the environment
• Time domains of physiological change- acute- chronic- evolutionary- development (life cycle changes)- circadian rhythms
• Chronic changes are acclimatisation
• Acute changes are typically neural or endocrine response
• Cutaneous- skin
• Tadpoles have gill & cutaneous gas exchange- Air breathing tadpoles has everything tadpoles have plus lungs- Adult frogs only have lung & cutaneous gas exchange
• Circadian rhythms- biological changes that occurs over approximately 24 hours or in association with the time of day
• Bad environments- high altitude- aquatic- deserts- under ice
• Aquatic environments are bad due to relatively low oxygen- high carbon dioxide- pollution- lack of light- fluctuating salinity
• Atacama desert- Chile- insanely dry- largest lithium reserve
• Fish have osmoregularity problems- ion regulation
• Brackish water- saltwater meets freshwater- estuaries
• Fish gills take on many of the same functions of the vertebrate kidney- ion regulation
• Giant, gutless tube worms- Riftia pachyptila- carbon isotopes resemble plants but no photosynthesis- high sulfide environment from vents- use sulfur instead of oxygen in the electron transport chain
• Nervous system can be split into 2 main categories- central nervous system & peripheral nervous system
• Afferent systems go to the CNS
• Efferent systems go away from the CNS
• The peripheral nervous system is further divided into the ANS & SNS
• ANS- autonomic nervous system- Sympathetic & parasympathetic nervous system
• SNS- somatic nervous system- actively controlled movement
• Action potential is generated at the soma- it propagates down the axon to the postsynaptic neuron
• Propagation- Neuron fires- Na+ channels open- depolarizes neuron- more positive & K+ channels open- neuron gets so positive that it repels + ions- Na+ gets pumped out