URINARY SYSTEM - Biology for Life

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Name Class Date
SECTION 49-3 REVIEW
URINARY SYSTEM
VOCABULARY REVIEW Define the following terms.
1. nephron
2. urethra
3. renal medulla
4. excretion
5. urea
MULTIPLE CHOICE Write the correct letter in the blank.
1. Most reabsorption within a nephron occurs in the
a. Bowman’s capsule.
b. duodenum.
2. Which of the following is not part of the nephron?
a. glomerulus b. loop of Henle c. ureter d. Bowman’s capsule
3. Which of the following substances would not normally be collected in the Bowman’s capsule?
a. small proteins b. glucose c. erythrocytes d. vitamins
4. The renal pelvis
a. empties into the renal vein.
b. is an extension of the ureter.
5. During the process of reabsorption, components of the filtrate are
a. actively transported out of the nephron.
b. transferred to the capillaries surrounding the nephron.
c. separated from waste products.
d. All of the above
c. collecting duct.
d. proximal convoluted tubule.
c. is a part of the nephron.
d. All of the above
Modern Biology Study Guide
275

Name Class Date
SHORT ANSWER Answer the questions in the space provided.
1. Describe the importance of filtration in urine production.
2. How do the kidneys contribute to homeostasis?
3. Why are nephrons considered the structural and functional units of the kidney?
4. Critical Thinking How is ammonia related to kidney functioning?
STRUCTURES AND FUNCTIONS Use the figure of a nephron and the information below
to answer the following questions.
About 99 of every 100 mL of filtrate
are reabsorbed into the blood, and
about 1,500 mL (1.6 qt) of urine are
excreted per day.
a
b
1. Label each part of the figure in the spaces provided.
2. In which structure is the filtrate collected?
3. Based on the amount of urine excreted daily, about how many milliliters of filtrate would be
produced daily by a pair of normally functioning kidneys?
276 Section 49-3 Review
c
d
e
f
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MULTIPLE CHOICE
1. c 2. c 3. a 4. c 5. b
SHORT ANSWER
1. No; most AIDS patients die from opportunistic
infections.
2. Yes; the immune system is able to combat HIV initially.
This period of infection without symptoms
may last up to 10 years following infection.
3. transfer of body fluids through sexual contact,
sharing hypodermic syringes, and receiving infected
organs or blood
4. Yes; HIV particles or infected cells may be found
within the transplanted organs or skin grafts. This
risk is known, and donor organs and grafts are
tested for HIV.
STRUCTURES AND FUNCTIONS
1. AIDS began six years after infection.
2. The number of helper T cells has decreased so
much that plasma cells can no longer be stimulated
to produce HIV antibody.
Section 49-1
VOCABULARY REVIEW
1. An organic nutrient contains carbon as one of its
elements. Inorganic nutrients do not contain carbon.
2. An unsaturated fat is a fatty acid that that has at
least one double bond between carbon atoms.
3. Dehydration causes the fluid volume of the body
to decrease. Water moves from intercellular
spaces to blood by osmosis. Eventually water is
drawn from the cells. As water is drawn the cytoplasm
becomes more concentrated until the cell
can no longer function. Dehydration also impairs
the body’s ability to regulate its temperature.
4. Vitamins function as coenzymes; that is, they activate
enzymes and help them function.
MULTIPLE CHOICE
1. d 2. a 3. d 4. c 5. c
SHORT ANSWER
1. Essential amino acids are those amino acids that
must be obtained from food. Nonessential amino
acids can be produced by the body.
2. Simple sugars are important because they represent
the final carbohydrate that must be formed before
absorption into the bloodstream, and the other carbohydrates
must be metabolized to simple sugars
before they can be used for energy production.
3. Water is important because it is a medium for
enzymatic reactions, it constitutes 90% of blood
volume, it is used in cellular waste removal, and it
helps regulate body temperature.
4. Nutrients are required for proper function and
growth.
STRUCTURES AND FUNCTIONS
1. group a, the carbohydrates
2. group c, animal products. No, essential amino acids
are also obtained from plant products and legumes.
Section 49-2
VOCABULARY REVIEW
1. The stomach, molars, and hard palate are involved
with mechanical digestion, or the physical breakdown
of food into small, easily digestible particles.
2. Gastric pits, gastric fluid, and saliva are involved
with chemical digestion, or the breakdown of food
into usable forms by enzymes.
3. Peristalsis is the series of rhythmic muscle contractions
that moves a bolus, or a ball, through
the esophagus.
4. The liver secretes bile into the gallbladder.
5. Absorption is the process during which the end
products of digested chyme are transferred from
the small intestine to the circulatory system.
MULTIPLE CHOICE
1. b 2. d 3. b 4. c 5. c
SHORT ANSWER
1. Mucus protects the stomach’s inner lining from
the digestive secretions.
2. Pepsin, a protease, catalyzes the breakdown of
proteins to peptides.
3. The pancreas secretes pancreatic fluid into the
small intestine. Pancreatic fluid assists in buffering
the chyme and has enzymes that hydrolyze disaccharides
into monosaccharides, fats into fatty
acids and glycerol, and proteins into amino acids.
4. The richest supply of blood capillaries should be
in the walls of the small intestine, specifically the
ileum and jejunum. These are the areas where the
absorption of the digested nutrients occurs. To
facilitate the absorption, a rich network of blood
capillaries is present in the small intestine.
STRUCTURES AND FUNCTIONS
1. a, esophagus; b, liver; c, large intestine; d, rectum;
e, mouth; f, stomach; g, small intestine
2. The liver stores glycogen, breaks down toxic substances,
and secretes bile, which digests fats.
3. Absorption takes place in the small intestine,
where villi and microvilli greatly increase the surface
area.
Section 49-3
VOCABULARY REVIEW
1. The nephron is the functional unit of the kidney
where urine is produced.
2. The urethra is the tube through which urine
passes from the urinary bladder out of the body.
3. The renal medulla is the inner two-thirds of
the kidney.
4. Excretion is the process of removing metabolic
wastes from the body. Students may also include
that during excretion, the metabolic wastes pass
through a membrane to leave the body.
5. Urea is a nitrogenous waste that is produced
from ammonia by the liver and then is removed
by the kidneys.
MULTIPLE CHOICE
1. d 2. c 3. c 4. b 5. d
SHORT ANSWER
1. Filtration is the initial step in urine formation. This
is when small compounds, including nitrogenous
waste products, are separated from the blood and
transferred to the nephron.
2. Kidneys assist in the maintenance of fluid volume,
blood pH, and the chemical composition of fluids.
3. The entire renal cortex and medulla are composed
of nephrons. Nephrons are considered the
functional units of the kidney because they
Modern Biology Study Guide Answer Key
41

perform all of the processes required for urine
production.
4. Ammonia is the first step in the production of
urea, which is excreted by kidneys.
STRUCTURES AND FUNCTIONS
1. a, proximal convoluted tubule; b, loop of Henle;
c, Bowman’s capsule; d, glomerulus; e, distal
convoluted tubule; f, collecting duct
2. The filtrate is collected in the Bowman’s capsule.
3. 150,000 mL per day.
Section 50-1
VOCABULARY REVIEW
1. The corpus callosum is the dense band of axons
that connects the cerebral hemispheres.
2. The brain and spinal cord make up the central
nervous system.
3. White matter consists of the axons of neurons.
4. Efferent neurons carry information away from the
central nervous system. Motor neurons are efferent
neurons.
5. The diencephalon consists of the hypothalamus
and thalamus.
MULTIPLE CHOICE
1. a 2. b 3. d 4. d 5. c
SHORT ANSWER
1. The limbic system functions in emotion, memory,
motivation, and other social behaviors.
2. The four major lobes of the brain are the frontal,
parietal, occipital, and temporal lobes.
3. Meninges are the three protective layers that surround
the central nervous system. Cerebrospinal
fluid is located between the inner (pia mater) and
middle (arachnoid) meninges and in the ventricles.
Together the meninges and cerebrospinal
fluid form a protective cushion and covering for
the neurons of the brain and spinal cord.
4. The ventral roots contain the axons of efferent
neurons (motor neurons), which carry information
away from the central nervous system.
5. Answers may vary but may include lesion studies;
brain-imaging techniques like PET, CT, and MRI;
behavioral and cognitive studies; electrical recording
techniques; and others.
STRUCTURES AND FUNCTIONS
1. structure A, the gray matter
2. It would eliminate sensory input to the spinal cord
from that spinal nerve.
3. It would eliminate sensory input and motor output
to and from the spinal cord from that spinal nerve.
Section 50-2
VOCABULARY REVIEW
1. The autonomic nervous system consists of the
sympathetic and parasympathetic divisions.
2. The somatic nervous system and the autonomic
nervous system are the two independent components
of the motor division of the peripheral nervous
system.
3. A reflex is an involuntary, generally self-protective
movement. A spinal reflex is a type of reflex that
involves only neurons of the body and the spinal
cord.
42
Modern Biology Study Guide Answer Key
4. The motor division is a component of the peripheral
nervous system.
MULTIPLE CHOICE:
1. b 2. c 3. c 4. b 5. c
SHORT ANSWER
1. In a state of physical or emotional stress, the sympathetic
division of the autonomic nervous system
redirects blood flow from the digestive system
toward the heart and skeletal muscles—the “fightor-flight”
response.
2. The autonomic nervous system is most important
for homeostasis because it acts constantly and involuntarily
to modulate the body’s internal conditions.
3. control of the skeletal muscles
4. No; the central and peripheral nervous systems
constantly interact. The spinal cord constantly
relays information to the brain from the body and
from the brain to the body.
STRUCTURES AND FUNCTIONS
1. The sensory (pain) receptor is located in the hand.
2. The biceps would contract to flex the arm.
3. The triceps (extensor muscles) would be inhibited
during the reflex.
Section 50-3
VOCABULARY REVIEW
1. Dendrites are extensions of neurons that receive
signals from other neurons.
2. Axon terminals are the ends of axons.
3. An action potential is the transmission of an electrical
impulse along the axon of a neuron.
4. A neurotransmitter is a chemical that is released
from axon terminals at synapses and that transmits
an electrical signal between neurons.
5. A synaptic cleft is the gap between adjacent neurons
across which neurotransmitters diffuse in
chemical synaptic transmission.
MULTIPLE CHOICE
1. c 2. b 3. c 4. d 5. d
SHORT ANSWER
1. A neurotransmitter can either increase or
decrease the activity of a postsynaptic neuron,
depending on the ion channels that are activated
by the neurotransmitter.
2. At resting potential, potassium ions are more concentrated
inside the cell, whereas sodium ions are
more concentrated outside the cell.
3. Action potentials conduct down an axon away
from the cell body and toward the axon terminal
because of the refractory period, the period of
time during which sodium channels cannot open
after an action potential.
4. Because ions cannot pass through the myelin
sheath, myelin increases the speed of the action
potential because the electrical impulse must “jump”
from node to node as it moves down the axon.
STRUCTURES AND FUNCTIONS
1. At the resting potential, voltage-gated sodium
channels are not open. Thus, sodium ions cannot
diffuse into the neuron.
2. Figure b shows the conduction of an action potential
down the axon. Sodium ions are flowing into
the cell, reversing the polarity of the cell.
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