Chapter 44 and 40- Regulating the internal environment Flashcards
Homeostasis
Maintaining a stable internal environment
What are some factors that animals must hold relatively constant?
• 4 things
- temp
- glucose
- blood pressure
- pH
How can homeostasis be measured?
• 3 steps
1. Sensor: Detects increased BP •deliver action potentials 2. Control center: Brain (medulla) •action potentials 3. Effector: perform response (decrease BP - dilate vessel)
Negative feedback
Input and Output are in opposite directions
3 elements of homeostasis
- Osmoregulation
- Excretion
- Thermoregulation
Osmoregulation
•definition
•what kind of animals
•2 strategies
- achieving proper water and salt balance
- live in diverse environments: aquatic, freshwater, marine, terrestrial
- Osmoconformers and osmoregulators
Osmolarity •formula •Human blood •Ocean •Freshwater
- Moles of solute/volume of solvent (H2O) = milliosmoles/liter
- 300
- 1000
- 50
Osmoconformers • solute concentration •main solute •Energy? •example
- same solute concentration as environment (isotonic/iso-osmotic)
- Sodium (Na)
- Spends no energy on osmoregulation
- marine invertebrate
Osmoregulators
•solute concentration
•energy?
•examples
- control solute concentration and differs from environment
- uses ATP
- Terrestrial animals: Freshwater and marine invertebrates
How do freshwater fish osmoregulate? •The problem •The solution: Urine,gills • Solutes and H2O •example
- They gain water
- Urine: dilute
- Gills: take up salt
- Hi solutes in and lo out
- Hi H2O out and lo in
- trout
How do saltwater fish osmoregulate? •The problem •The solution: Urine,gills • Solutes and H2O •example
- water loss
- Urine: concentrated
- Gills: Pumps out salt
- Hi solutes out and lo in
- Hi water in and lo out
- cod
How do terrestrail animals osmoregulate?
•The problem and why?
•how do they gain H2O? lose?
- water loss because they are not surrounded by water
- By eating and drinking
- By sweating, urine, breathing, and feces
Anhydrobiosis
Animals that can survive extreme hydration and live in temporary water
What generates nitrogen-containing waste?
Protein an nucleic acid metabolism
-NH2 amino groups converted to
Ammonia (NH3)
3 types of nitrogenous wastes
- Ammonia
- Urea
- Uric Acid
Ammonia • Toxicity • Energy required to produce it • Water required to eliminate it • Animals that excrete this type of waste
- Highly toxic
- Low energy
- High (diluted in H2O)
- Fish
Urea • Toxicity • Energy required to produce it • Water required to eliminate it • Animals that excrete this type of waste
- Medium
- Medium amount
- Medium amount
- Mammals and amphibians
Uric Acid • Toxicity • Energy required to produce it • Water required to eliminate it • Animals that excrete this type of waste
- Low
- High amounts
- Low (Excreted as a pasty precipitate)
- Birds, reptiles, insects
4 steps for excretion
•Basic feature
•steps
•built on tubes
- Filtration
- Reabsorption
- Secretion
- Excretion
Filtration
Body fluid enter tube and it filtrates the fluid
Reabsorption
•definition
•examples
- Return of substances in filtrate to animal body
* Glucose, AA, Na+
Secretion
•definition
•examples
- add substances to filtrate
* drugs, acid
Excretion
excrete urine from body
4 excretory systems
- protonephridia
- metanephridia
- malpighian tubules
- Kidney
Protonephridia
•present in
•how does it work
•Planaria (phylum Platyhelminthes)
- Body fluid enters the flame bulb
- Cilia inside bulb draw fluid in
- Fluid flows into tubule and through pore in body wall
Metanephridia •present in • 4 steps •how many per segment • what is reabsorbed and by what •what kind of urine is produced
•earthworms and mollusks •1. Internal opening 2. Collecting tubule 3. Bladder 4. External opening •one per segment • Salts (Na+) reabsorbed by collecting tubule • dilute
Malpighian tubules •present in •made of • 5 steps • Advantage
•insects •tubes connected to digestive tract 1. Body fluids (salts, water, waste) enters malpighian 2. Fluid enters intestine 3. Reabsorbs H2O to body 4. Feces and urine combination is left behind 5. 1 waste is excreted from anus • H2O conservation
Kidney
•present in
•the 2 kidneys are what percent of body weight
•how much blood flow do kidneys receive
- vertebrates
- 1%
- 25%
Ureter
Transport urine to bladder