Thermoregulation and Body Fluids

exam 4

thermoregulation in ectotherms and endotherms

Ectotherms:

• Temp: Environment-dependent

• Regulate: Behavior

• Heat: External

• Example: Reptile

Endotherms:

• Temp: Stable internal

• Regulate: Internal heat

• Heat: Metabolic

• Example: Mammal

four modes of heat transfer between an organism and the environment, and adaptations that help organisms achieve thermoregulation

Heat Transfer Modes:

• Radiation: Heat via infrared waves.

• Conduction: Direct heat transfer (touch).

• Convection: Heat transfer via fluid (air/water) movement.

• Evaporation: Heat loss via liquid turning to gas.

(fur, cooling, sweating, burrowing, shivering)

Osmoregulation includes both conformers and regulators – what do these terms mean?

Osmoconformers:

• Body fluids match the environment's solute concentration.

• "Go with the flow" osmotically.

Osmoregulators:

• Control their internal solute concentration.

• Maintain a stable internal environment despite external changes.

What are the different strategies that fish use to osmoregulate depending on whether they live in fresh (=hypotonic) or salt (= hypertonic) water;

Freshwater Fish (Hypotonic Environment):

• Problem: Water rushes IN, salts leak OUT.

• Solution:

  • Don't drink much water.

  • Produce lots of dilute urine to get rid of excess water

  • Actively pump salts IN through gills.

Saltwater Fish (Hypertonic Environment):

• Problem: Water rushes OUT, salts rush IN.

• Solution:

  • Drink lots of seawater.

  • Produce small amounts of concentrated urine to conserve water and get rid of some salt.

  • Actively pump salts OUT through gills.

what does excretion accomplish?

• Removes metabolic wastes (e.g., urea, ammonia).  

• Maintains fluid balance.  

• Regulates salt concentrations.

What are the three forms of nitrogenous waste?

• Ammonia (NH3​): Most toxic.  

• Urea (CO(NH2​)2​): Intermediate toxicity.

• Uric Acid (C5​H4​N4​O3​): Least toxic.  

Sources and related content

Why must certain organisms form uric acid instead of urea?

• Saves water: Less water needed for excretion.

• Low toxicity: Can be stored with less harm (e.g., in eggs).

• Key for: Dry environments & shelled eggs.

kidney structure and function

Kidney Structure:

• Outer: Cortex (nephrons)

• Inner: Medulla (pyramids, tubes)

• Center: Pelvis (collects urine)

• Nephron: Filtering unit (glomerulus + tubule)

Kidney Function:

• Filters blood → urine

• Removes waste

• Balances water & salts

the four key processes which occur in the kidney

Four Key Processes:

1. Filtration: Blood → nephron (small stuff)

2. Reabsorption: Nephron → blood (good stuff)

3. Secretion: Blood → nephron (extra waste)

4. Excretion: Urine leaves the body

What is the significance of a long loop of Henle with respect to water retention?

A long loop of Henle creates a very salty environment in the kidney's inner part. This saltiness pulls more water out of the forming urine, allowing the animal to conserve water and produce concentrated waste