Chapter 32: Regulation Of Temperature And Body Fluids

Question 1

Thermoregulation

Answer 1

Control of body temperature, and it requires the ability to balance heat gained from and lost to the environment.

Question 2

Ectotherm

Answer 2

Lacks an internal temperature-regulating mechanism.

It thermoregulates by moving to areas where it can gain or lose heat.

Uses less energy.

Examples: invertebrates, fishes, amphibians, and no avian reptiles.

Question 3

Endotherm

Answer 3

Regulates body temperature internally. Maintains constant body temperature by balancing heat generated in metabolism with heat lost to the environment.

High metabolic rate requires much more food than Ectotherms.

Examples: mammals and birds.

Question 4

Concurrent exchange system

Answer 4

An adaptation to extreme cold. Two adjacent currents flow in opposite directions and exchange heat with each other. Conserves heat.

Question 5

Hypothalamus

Answer 5

Part of the brain that detects blood temperature, receives information from thermoreceptors in the skin and other organs, and controls many of the responses that maintain homeostasis.

Question 6

Osmoregulate

Answer 6

Control the concentration of ions in body fluids as the environment changes. Manage the gain and loss of water, ions, or both.

Requires cells to move ions against their concentration gradient (active transport) requires energy in the form of ATP.

Question 7

Two main categories of waste

Answer 7

1. Feces: undigested food that passes through digestive tract without ever entering the body’s cells
2. Waste produced by body’s cells

Question 8

Excretion

Answer 8

Elimination of metabolic wastes produced by the body’s cells.

Question 9

Ammonia (aquatic animals)

Answer 9

• Requires very little energy to excrete
• Very toxic
• ## Aquatic invertebrates, most bony fishes, tadpoles and salamanders excrete ammonia in a diluted solution. Ammonia enters the water by simply diffusing out of the blood that flows through the gills.

Question 10

Ammonia (land animals)

Answer 10

• Expends a lot of energy to convert ammonia to urea or uric acid.
• Both of higher concentrations of nitrogen
• Less toxic

Question 11

Urea

Answer 11

• Formed by mammals, adult frogs and toads, turtles, and cartilaginous fishes (sharks and rays)
• Urea is formed by the liver as cells breakdown proteins.
• Moves to the bloodstream and is eliminated with water in urine.
• Sharks retain urea which help with osmoregulation in their salty habitat.

Question 12

Uric acid

Answer 12

• produced by insects, land tortoises, lizards, and birds
• insoluble in water so it is excreted in solid form
• birds, insects and spiders excrete uric acid through undigested food

Question 13

Malpighian tubules

Answer 13

• Excretory structures that empty into the gut
• the cells lining the tubules use active transport to move uric acid and ions.
• fluid in the tubules enters the intestine, where cells lining the rectum reabsorb most of the k+ and water. The uric acid mixes with the undigested food, which is eliminated through its anus.

Question 14

Learning objective: contrast the three forms of nitrogenous waste excreted by animals, in terms of toxicity, solubility, and chemical composition. Cite the advantages and disadvantages of excreting each.

Answer 14

Ammonia: most toxic, soluble in water, consumes very little energy
Urea: less toxic than ammonia, less dilution, higher concentrations of nitrogen, expends a lot of energy. Eliminated with water through urine.
Uric acid: insoluble in water, excreted in solid form, see urea

Question 15

What does the human urinary system do?

Answer 15

Filters blood, eliminates nitrogenous wastes, and helps maintain the ion concentration of body fluids.

Question 16

What are the major excretory organs in the urinary system?

Answer 16

The paired kidneys. Size of an adult fist and weighs about 230 grams.

Question 17

How is urine formed?

Answer 17

While the kidney cleanses the blood.

Question 18

Kidney functions

Answer 18

• Eliminate urea and other toxic substances
• Conserve water, salts, glucose, amino acids and other valuable nutrients
• Regulate blood ph
• Regulate volume of blood by controlling the amount of water lost in urine.

Question 19

Ureter

Answer 19

A muscular tube where the urine from each kidney drains into.

Question 20

Peristalsis

Answer 20

Waves of smooth muscle contraction that squeeze the fluid along the two ureters and squirt it into the urinary bladder.

Question 21

Urinary bladder

Answer 21

Saclike muscular organ that collects urine.

Question 22

Urethra

Answer 22

Tube that connects the bladder with the outside of the body.

In females, opens up between the clitoris and vagina.
In males, it extends the length of the penis. Also carries semen.

Question 23

Urinary process

Answer 23

Receptors send impulses to the spinal cord, which stimulates sensory neurons that contract the bladder muscles.

Can suppress the urge to urinate by contracting external sphincter. The cerebral cortex directs the sphincters to relax and bladder muscle contractions force urine out of body.

Question 24

LO: Contrast the anatomy of the excretory systems of humans and insects (32.3 and 32.4). In the insect’s Malpighian tubules and the human’s urinary system, describe the relationship of nitrogenous waste to feces and the gut.

Answer 24

Insects have a malphigian tubule and humans do not.

Nitrogenous gases are released in urine in humans. The kidney eliminates urea. Insects excrete uric acid in a solid form.

Question 25

Nephrons

Answer 25

The functional units of the kidney. Each nephron is entertained with a network of capillaries.

Consists of two main parts:
Glomerular capsule
A renal tubule

Question 26

Glomerulus

Answer 26

Tuft of capillaries where blood is filtered into the nephron. The capillaries converge into another arteriole.

Pores allow water, urea, glucose, salts, amino acids, and creatinine to pass into glomerular capsule.

Question 27

Peritubular capillaries

Answer 27

Snakes around part of each nephron. These blood vessels empty into a venule.

Question 28

Kidney process

Answer 28

Receives blood via a renal artery, which branches into multiple arteries and arterioles. An arteriole delivers blood to the glomerulus then converges to Peritubular capillaries that empty into a venule which joins the renal vein carrying cleansed blood out of the kidney and to the heart.

Question 29

Glomerularn (Bowman’s) capsule

Answer 29

Located in the kidney’s outer portion, or cortex. Surrounds the glomerulus. Receives blood from the Glomerulus. One part of a nephron.

Question 30

Renal tubule

Answer 30

The solution from the glomerular (Bowman’s) capsule travels along the renal tubule, which are winding passageways consisting of three functional regions:
Proximal convoluted tubule
The nephron loop
Distal convoluted tubule

Question 31

Proximal convoluted tubule

Answer 31

Part of the renal tubule of a nephron. Leads from the glomerular capsule to the hairpin-shaped nephron loop.

Selective reabsorption and secretion occurs here. Work together to maintain a pH of blood between 7 and 8.

Question 32

Nephron loop

Answer 32

Part of the renal tubule of a nephron. Hair-shaped turn into the medulla. The descending limb of the nephron loop dips into the renal medulla toward the kidney’s center and the ascending limb returns to the distal convoluted tubule.

The filtrate flows in the opposite direction of the blood in surrounding capillaries.

Question 33

Distal convoluted tubule

Answer 33

The ascending part of the nephron loop returns here.

Sodium ions and CI- ions move out of the filtrate and into the blood by active transport. Once filtrate has passed here 97% of water in the original glomerular filtrate has been reabsorbed and little salt remains.

Question 34

Collecting duct

Answer 34

Receives the fluid from several nephrons. Urine accumulates in the funnel-like renal pelvis before entering the ureter and urinary bladder and moving out of the body through the urethra.

Remaining water leaves here by osmosis.

Question 35

LO: Trace the processing of filtrate through the nephron of a human kidney, including the glomerulus, Bowman’s capsule, proximal convoluted tubule, descending and ascending portions of the loop of Henle, distal convoluted tubule, and the collecting duct (32.5A, C-E).

Answer 35

Each kidney receives blood via a renal artery, which
branches into multiple arteries and arterioles. An arteriole delivers
blood to a glomerulus, a tuft of capillaries where blood is
fi ltered into the nephron. The capillaries of the glomerulus then
converge into another arteriole, which leads to the peritubular
capillaries that snake around part of each nephron. These blood
vessels empty into a venule, which joins the renal vein carrying
cleansed blood out of the kidney and (ultimately) to the heart.

See proximal, nephron loop and distal tubules and collecting duct.

Question 36

Three processes of urine formation

Answer 36

Filtration, reabsorption and secretion

Question 37

Filtration

Answer 37

Water and dissolved substances are filtered out of the blood at the glomerular capsule.

Question 38

Reabsorption

Answer 38

Useful materials such as salts, water, glucose and amino acids return from the nephron to the blood.

Question 39

Secretion

Answer 39

Toxic substances, drug residues, hydrogen ions and surplus ions are secreted into the nephron to be eliminated in urine.

Question 40

Anti diuretic hormone (ADH)

Answer 40

A peptide hormone that triggers the formation of additional water channels in the walls of the distal convoluted tubule and collecting duct. As a result, the blood reabsorbs more water and the urine becomes very concentrated.

Question 41

Aldosterone

Answer 41

Steroid hormone that stimulates the production of sodium channels in the distal convoluted tubule.

Produced when blood pressure and blood volume dip too low.

Question 42

LO: Explain the effects on urine production of antidiuretic hormone (ADH), ethyl alcohol and caffeine (32.5F).

Answer 42

ADH allows the blood to reabsorb more water making the urine more concentrated

Ethyl alcohol stimulates urine production by reducing ADH secretion, thereby decreasing the permeability of the tubules to water which intensifies thirst.

Aldosterone: Steroid hormone that stimulates the production of sodium channels in the distal convoluted tubule.

Question 43

LO: Compare a kidney dialysis machine with a normal kidney

Answer 43

The dialysis machine pumps blood out of the patient’s body and past a semipermeable membrane. Wastes and toxins, along with water, diffuse
across the membrane to a waste fluid called “dialysate,” but blood cells do not. The cleaned blood then circulates back to the patient’s body.
Dialysis membranes cannot replace all of the kidney’s functions.
For example, nephrons selectively recycle useful components such as
glucose and salts to the blood. The dialysis machine cannot do this,
although a technician can adjust the concentrations of these dissolved
compounds in the dialysate to promote or inhibit diffusion from the
blood.

Question 44

LO: What kinds of information about the body are provided urinalysis?

Answer 44

Too much glucose can be a sign of diabetes, high carb diet or stress.

Albumin which means damaged nephrons.

UTI

Traces of drugs

Colorless urine indicates excess water intake or ingestion of diuretics like alcohol or coffee. A reddish tinge means bleeding in the urinary tract, beet consumption or mercury poisoning. Vitamin C and carrots can change urine color to orange.