Key Points From Last Lecture Homeostasis is made possible by physiological negative feedback loops...
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Transcript of Key Points From Last Lecture Homeostasis is made possible by physiological negative feedback loops...
Key Points From Last Lecture
Homeostasis is made possible by physiological negative feedback loops
Osmoregulation: Evolutionary trend towards greater control of osmoregulation, waste secretion
Outline/Key Points:
Kidneys filter blood, regulate osmolarity (two functions)
- Human kidneys
- Concentration gradient/kidney function
Water/salt needs of different animals are different
- Too much water/too little salt
- Too little water/too much salt
The Kidney Filters Wastes from Blood, and is the Effecter of Osmoregulation
Fig 32_13
The Kidney performs two functions - osmoregulation and recovery of valuable materials
Low salt concentration - No water crosses tubule
High salt concentration - allows passive diffusion of water out of waste - birds and mammals
Active recovery of valuable materials
The Kidney is an Effecter in a Negative Feedback Loop Allowing Osmoregulation
Pg 626
Organisms Face Different Challenges to Osmoregulation Based on their Environment
Fig 32_10
Either too little or too much water/salt
Marine environments are analogous to deserts
In freshwater environments salts and minerals are limited
Three Types of Nitrogenous Waste
Fig 32_14
Type of waste and the amount of dilutions follows phylogeny
Too Much Water/Too Little Salt
Bodies are saltier than environment = water moves in salt moves out
Fig 32_8
Too Little Water/Too Much Salt
Environment is saltier than body = water moves out salt moves in
Fig 32_8
Additional Physiological Adaptations Involved in Osmoregulation
Fig 32_9
Fig 32_12
Urea is deteoxified, used to raise osmolarity of blood which prevents water loss
Salt in diet, specialized organ to eliminate salt
Elasmobranch (marine) Marine bird