Biology 121 - Ch. 25

Animal specializations for thermoregulation:

(1) metabolic heat production and (2) insulation (3) circulatory specializations(4) evaporative cooling and (5) behavioral responses

evaporation

- loss of heat from the surface of a liquid that is losing some of its molecules as a gas

Nephron reabsorption

Active or Passive, pushes things out of nephron back to blood

circulatory specializations

Adjust amount of blood flowing to the skin - Dilate blood vessels, more blood flows to the skin, more heat loss - Constrict blood vessels, less blood flows to the skin, less heat loss Adjust amount of blood flowing to the skin - Counter-current heat exchange, warm and cold blood flow in opposite directions in adjacent blood vessels

Behavioral Responses

Adjust behavior in response to the environment - e.g., birds migrate, penguins huddling, lizard basking, humans wearing clothes

What is the advantage of excreting nitrogenous waste in the form of ammonia?

Ammonia excretion conserves energy.

Which of the following statements regarding the urinary system is TRUE?

Bowman's capsule envelops the glomerulus.

Which of the following statements regarding freshwater fish is TRUE?

Freshwater fish use their gills to actively take up salt ions.

insulation

Mammals and birds Such as hair, fur, feathers, fat (blubber) - Reduces heat loss to the environment

the maintenance of solute (dissolved substance) concentrations within an optimal range and the balance of water gain and loss is called

Osmoregulation

organism who maintain their body fluid at a solute concentration different from that of its surroundings and use energy to actively control water movement are called

Osmoregulator

the passive diffusion of water across a membrane, from a solution with a lower solute concentration to one with a higher solute concentration is known as

Osmosis

Which of the following statements regarding saltwater fish is TRUE?

The concentration of solutes in the internal fluids of saltwater fish is much lower than in the surrounding water.

Evaporative Cooling

Water absorbs heat from the body surface, and the heat is removed when the water turns to vapor (evaporation) - e.g., Human sweating, elephant spraying water, dog panting

The transfer of heat from arteries carrying warm blood past veins returning cooler blood is an example of

a countercurrent heat exchanger

Which of the following by-products of metabolism is most toxic?

ammonia

Secretion is the movement of substances such as drugs or toxic molecules from the ________ into the ________.

blood . . . filtrate

Which of the following is a function of the vertebrate liver?

combining ammonia and carbon dioxide to form urea

What do urine contain of?

concentrated waste solutes (toxins, acid, drugs)

transfer of heat through direct contact

conduction

It is a cool winter evening, and you are feeling a little chilled. To warm yourself up, you sip some warm tea. As you swallow, you can feel the tea warm your mouth and throat. This tea is warming you up by the process of

convection.

Animals that maintain heat from external sources are called

ectotherms.

Animals that maintain internal body temperature using heat generated by their own metabolism are called

endotherms.

Which of the following processes involves heat exchange between an animal and its environment?

evaporation

To enhance heat loss, humans sweat, an adaptation known as

evaporative cooling.

What do tubules do in the kidney?

first remove filtrate (water, urea, useful and waste solutes) then return useful solutes and water back to blood cleaned blood returns to body through renal vein

Which of the following kinds of animals excrete their nitrogenous waste entirely as ammonia?

fish

The first step in the formation of urine is the

formation of filtrate that enters Bowman's capsule.

Which of the following options correctly lists the structures in the kidney in the order in which fluid flows through them?

glomerulus, Bowman's capsule, proximal tubule, loop of Henle, distal tubule

When a salmon moves from the ocean to a freshwater environment, you would expect its urine volume to ________ and its rate of salt absorption to ________.

increase . . . increase

Which of the following physiological responses occurs in the human body when it becomes overheated?

increased blood flow to the skin

The land animals that evolved from earlier aquatic forms had to change their mechanisms for excreting nitrogenous wastes because

land animals had a more difficult time with water balance than aquatic species since water was not always available on land.

Which of the following is a function of the excretory system?

maintenance of water balance

What is the name of the functional unit of the kidney?

nephron

Marine animals that have body fluids with a solute concentration equal to that of the surrounding seawater are... they cannot regulate solutes in their body fluids at a concentration diff from surrounding

osmoconformers.

Water moves out of filtrate in the nephron tubule into the interstitial fluid by

osmosis.

To conserve precious salts, freshwater fish

produce large amounts of urine.

emission of electromagnetic waves that can transfer heat b/t entities

radiation

The overall process that refines the filtrate and ultimately returns water and valuable solutes to the blood is known as

reabsorption.

Metabolic Heat Production

the heat produced by cells - When cells perform work, heat is produced - More work, more heat; less work, less heat

Thermoregulation, an important part of homeostasis, is defined as

the maintenance of internal body temperature within a tolerable range.

Urinary System

the organ system that (1) forms and excretes urine while (2) regulating the amount of water and solutes in body fluids

How does urine leave the kidney?

through the ureter, eliminated through urethra (urination)

What is the function of antidiuretic hormone?

to increase water reabsorption

convection

transfer of heat by movement of air or liquid past a surface

Through which of the following structures does urine leave the bladder?

urethra

Birds, like other animals, must eliminate ammonia or urea, and do so by converting them to

uric acid.

During filtration in the glomerulus, which of the following will enter Bowman's capsule from the bloodstream?

water

When a salmon leaves the river and moves out to sea, you would expect ________ to leave its body by osmosis and that excess ________ would need to be pumped out.

water . . . salt

During production of urine, a major function of the kidney is

water conservation.

Functions of nephrons

• Extract filtrate from blood • Return useful solutes and 99% of water to blood • Remove more toxins and drugs from blood • Produce urine

Osmoregulation in saltwater fish:

• live in a hypertonic environment • must drink seawater to replace water lost by osmosis from their body surfaces • must lose salt by drinking water, pumping excess salt through gills, concentrating urine from kiddneys & loss of small amounts of water

Osmoregulation in freshwater fish

• live in a hypotonic environment • must urinate the excess water gained by osmosis through their body surface • must replace salt lost by diffusion to freshwater; loss of salt and large amounts of water in dilute urine from kidneys

Osmoregulation in land animals

• risk dehydration • lose water across skin and moist respiratory surfaces, also in urine and feces • gain water by drinking, eating, and cellular functions • save water with traits such as waterproof outer surfaces, waterproof egg shells, and kidneys that conserve water