BIOL 1040: Masteringbiology: Exam 3

What type of cell makes up the myelin sheath of a motor neuron?

Schwann cells

A fertilized egg usually implants itself and develops in the _____. a. uterus b. ovary c. oviduct d. abdominal cavity e. none of these

a

After ovulation, high levels of _____ inhibit _____ secretion. a. estrogen and progesterone ... FSH and LH b. FSH and LH ... estrogen and progesterone c. HCG ... estrogen and progesterone d. estrogen ... FSH androgens ... FSH and LH

a

In the course of normal events leading to fertilization and eventually birth, the route of the egg, embryo, and finally fetus is from the ovary into the __________. a. ovary, into the oviduct, to the uterus, and then out the vagina b. oviduct, to the bladder, and then out the urethra c. urethra, to the labia, to the uterus, and then out the vagina d. uterus, to the oviduct, and then out the vagina

a

The sodium-potassium pump __________. View Available Hint(s) a. expels sodium from the cell b. pumps sodium into the cell c. expels sodium and potassium from the cell d. pumps sodium and potassium into the cell

a

The space between an axon of one neuron and the dendrite of another neuron is called a(n) _____. a. synaptic cleft b. node of Ranvier c. internodes d. synapse e. synaptic terminal

a

Unlike the somatic nervous system, the autonomic nervous system is __________. a. involuntary and primarily controls smooth and cardiac muscle b. voluntary and primarily controls smooth and cardiac muscle c. involuntary and primarily controls skeletal muscle d. regulated only by the endocrine system

a

When a neuron is at its resting potential a. there are more potassium ions inside the neuron than outside. b. the inside of the cell is positively charged relative to the outside. c. sodium-potassium pumps transport sodium ions into the cell. d. gated sodium channels are open. e. sodium-potassium pumps transport both sodium and potassium ions out of the cell.

a

Which hormone(s) is(are) directly responsible for triggering the development of the secondary sex characteristics of males, such as beard growth? a. androgens b. thymosin c. epinephrine d. insulin e. parathyroid hormone

a

Which of the following choices correctly describes an action potential? a. An action potential is an all-or-none event moving in one direction. A stronger stimulus generates a faster frequency of action potentials moving to the central nervous system from the sensory structure. b. An action potential is a graded event moving in two directions. A stronger stimulus generates a stronger action potential moving back and forth between the central nervous system and the sensory structure. c. An action potential is a graded event moving in one direction. A stronger stimulus generates a stronger action potential moving to the central nervous system from the sensory structure. d. An action potential is an all-or-none event moving in two directions. A stronger stimulus generates a faster frequency moving back and forth between the central nervous system and the sensory structure.

a

Which of the following events is the first to occur during an action potential? a. Sodium channels open. b. Sodium ions flow into the neuron, making the inside of the neuron positively charged relative to the outside. c. Potassium ions flow out of the neuron. d. Sodium channels close. e. Potassium channels open.

a

Which of the following is characteristic of vertebrate nervous systems? a. a distinct central nervous system consisting of a brain and spinal cord b. a spinal cord that runs outside the vertebral column and gives rise to a series of cranial nerves c. only partially centralized and cephalized d. a spinal cord with homeostatic control centers that keep the body functioning smoothly

a

Which of the following statements about the female reproductive system is FALSE? a. The labia majora is a thin piece of tissue that partially covers the opening of the vagina. b. The endometrium, richly supplied with blood vessels, is where the young embryo implants. c. When people speak of the "womb," they are referring to the uterus. d. An ectopic pregnancy occurs when an embryo implants outside of the uterus.

a

Which of the following statements about the transmission across a typical chemical synapse is true? a. Neurotransmitter molecules bind to receptors in the receiving neuron's plasma membrane. b. Vesicles containing neurotransmitter molecules diffuse to the receiving neuron's plasma membrane. c. Action potentials trigger chemical changes that make the neurotransmitter vesicles fuse with the plasma membrane of the receiving neuron. d. Neurotransmitter molecules are stored in vesicles in the axon.

a

Which pituitary secretion stimulates the testes to secrete androgens? a. LH b. ACTH c. TSH d. PRL e. FSH

a

Which reproductive method is used most frequently by mammals? a. internal fertilization b. fragmentation c. external fertilization d. regeneration

a

External fertilization occurs mostly in ________

aquatic animals

A nerve impulse moves away from a neuron's cell body along _____.

axons

A stimulus triggers an action potential by _____. a. activating the sodium-potassium pump b. causing sodium ions to enter the neuron c. causing potassium ions to enter the neuron d. causing sodium ions to leak out of the neuron

b

An action potential is triggered when __________. a. sodium ions (Na+) diffuse out of the cytoplasm at the trigger zone b. during the depolarization phase, sodium ions diffuse into the cell and the interior of the cell becomes more positive, and, if threshold potential is reached, the action potential is triggered c. potassium ions (K+) diffuse into the cytoplasm along the axon d. calcium ions (Ca++) diffuse into the cytoplasm at the dendrites

b

Developing ovarian follicles primarily secrete _____. a. progesterone b. estrogens c. luteinizing hormone d. follicle-stimulating hormone e. human chorionic gonadotropin

b

During an action potential a. potassium ions move into the neuron. b. the inside of the neuron becomes positively charged relative to the outside. c. the inside of the neuron becomes negatively charged relative to the outside. d. potassium channels open first, followed by sodium channels. e. sodium ions move into the neuron, then potassium ions move in.

b

How are neurons structurally adapted to chemically transmit impulses to neighboring neurons? a. They have numerous nodes of Ranvier. b. Synaptic terminals contain neurotransmitter substances within synaptic vesicles. c. They have numerous dendrites. d. They have Schwann cells that surround axons.

b

If there is no fertilization, degeneration of the corpus luteum results in a drop in _____, which results in the sloughing off of the uterus's endometrium. a. FSH b. estrogen and progesterone c. hypothalamic secretion of releasing hormones d. HCG e. LH

b

Into which structure is a human oocyte released upon ovulation? a. ovary b. oviduct c. uterus d. corpus luteum

b

Sperm exit a male's body via the _____. a. ejaculatory duct b. urethra c. oviduct d. ureter e. epididymis

b

The route that sperm take from formation to ejaculation from the penis is from the testes to __________. a. the vas deferens, epididymis, ejaculatory duct, and urethra b. the epididymis, vas deferens, ejaculatory duct, and urethra c. the vas deferens, ejaculatory duct, epididymis, and urethra d. the urethra, epididymis, ejaculatory duct, and vas deferens

b

The secretion of androgens is regulated by a _____ feedback mechanism involving the _____ and _____. a. positive ... hypothalamus ... pituitary gland b. negative ... hypothalamus ... pituitary gland c. positive ... thyroid ... pituitary gland d. negative ... pancreas ... pituitary gland e. negative ... seminal vesicles ... prostate gland

b

What is the source of the hormones that, when suddenly absent, are directly responsible for the onset of menstruation? a. ovarian follicle b. corpus luteum c. pituitary d. hypothalamus

b

What role do neurotransmitters play in neuron communication? a. They regulate rhythmic muscle contractions, such as those that occur in the small intestine. b. Neurotransmitters are chemical signals that carry information across a gap called the synaptic cleft and may or may not generate an action potential in neighboring neurons. c. They are accepted into the receiving cell, where they initiate more action potentials. d. They relay electrical signals from one axon to the next axon.

b

When neurotransmitter molecules bind to receptors in the plasma membrane of the receiving neuron, a. the receiving neuron becomes more positive inside. b. ion channels in the plasma membrane of the receiving neuron open. c. ion channels in the plasma membrane of the sending neuron open. d. vesicles in the synaptic terminal fuse to the plasma membrane of the sending neuron. e. the receiving neuron becomes more negative inside.

b

Which of the following structures is exclusively found in the peripheral nervous system? a. medulla oblongata b. sensory nerves associated with taste receptors on the tongue c. spinal cord d. gray matter

b

A rapid increase in the _____ level stimulates ovulation. a. progesterone estrogen b. luteinizing hormone c. follicle-stimulating hormone d. human chorionic gonadotropin

c

If a signal from a sending neuron makes the receiving neuron more negative inside, a. the receiving neuron immediately generates an action potential. b. the sending neuron becomes more negative inside. c. the receiving neuron is less likely to generate an action potential. d. the receiving neuron is more likely to generate an action potential. e. the sending neuron becomes more positive inside.

c

In humans, the testes are located outside the abdominal cavity within the scrotum because __________. a. this location allows for a shorter pathway to the urethra b. blood flow to the scrotum is not interrupted during erection c. sperm are unable to mature properly at the higher temperatures found within the abdominal cavity d. the elevated pressure within the abdominal cavity would collapse the small passageways within the testes

c

Ovulation usually occurs on or about day _____ of a 28-day ovarian cycle. a. 1 b. 7 c. 14 d. 21 e. 28

c

Sperm develop in the _____. a. prostate gland b. bulbourethral glands c. seminiferous tubules d. hypothalamus e. seminal vesicles

c

The hormone that initiates the development of specialized cells in the ovaries of women and triggers androgen production by the testes of men is _____. a. follicle-stimulating hormone (FSH) b. estrogen c. luteinizing hormone (LH) d. progesterone

c

The rapid flip-flop of a neuron's membrane potential occurs as __________. a. sodium ions rush into the neuron, and then other sodium ions rush out b. potassium ions rush into the neuron, and then sodium ions rush out c. sodium ions rush into the neuron, and then potassium ions rush out d. potassium ions rush into the neuron, and then other potassium ions rush out

c

The type of neuron that when stimulated by the environment transmits an impulse to the central nervous system is __________. a. an autonomic neuron b. an interneuron c. a sensory neuron d. a motor neuron

c

What is the difference between a neuron and a nerve? a. Neurons are made of white matter, nerves of gray matter. b. Nerves are found only in the central nervous system. c. They consist of different numbers of cells. d. One is sensory in function, the other motor.

c

What is the usual site of the fertilization of an egg cell? a. uterus b. ovary c. oviduct d. abdominal cavity e. vagina

c

What prevents menstruation when a woman first becomes pregnant? a. The pituitary gland increases its secretion of LH and FSH. b. The corpus luteum releases HCG. c. The release of HCG from the implanted embryo stimulates the corpus luteum to continue to secrete progesterone and estrogen. d. The developing placenta of the embryo presses against blood vessels of the endometrium, preventing the fluid from escaping.

c

Which male reproductive structures are responsible for the transport and delivery of sperm? a. Seminal vesicles, prostate gland, and bulbourethral gland b .Seminal vesicles, vas deferens, and urethra c. Vas deferens, urethra, and penis d. Testis and epidydymis

c

Which of the following categories includes all the others? a. motor division b. enteric division c. peripheral nervous system (PNS) d. autonomic nervous system (ANS)

c

Which of the following maintains the resting potential (the difference in the electrical charge inside and outside a neuron) that enables the cell to transmit a signal? a. the myelin sheath, which prevents ions from entering or leaving the neuron b. charges that pull sodium and potassium through the membrane c. the active transport and leakage of sodium ions, potassium ions, chloride ions, and various anions into and out of the cell d. the opening of sodium and potassium channels in the membrane

c

Which of the following statements about chemical synapses is FALSE? a. The closer the synapse is to the base of the receiving cell's axon, the stronger the effect. b. Neurotransmitters that bind to receptors controlling excitatory membrane channels increase the tendency to develop action potentials. c. Receiving neurons receive either inhibitory or excitatory signals, but not both. d. Neurotransmitters that bind to receptors controlling inhibitory membrane channels decrease the tendency to develop action potentials.

c

Which of the following statements about the male reproductive system is FALSE? a. The urethra in men, but not women, participates in reproduction and urine transport. b. The testes have dual roles, producing gametes and hormones. c. The glans portion of the penis contributes to semen. d. The scrotum permits sperm to develop below the core body temperature.

c

Action potentials are generated along a neuron because _____. a. of cytoplasmic streaming within the neuron b. the neuron cytoskeleton conducts electricity as long as an ion gradient is maintained by the sodium-potassium pump c. they are pulled along by positive-negative attraction d. depolarization of the membrane at one point causes an increase of permeability to sodium at the next point

d

After ovulation occurs, the empty follicle _____. a. quickly degenerates b. immediately initiates menstruation c. can be recycled to produce more eggs d. changes into the corpus luteum and makes hormones

d

Compared to animals that have separate sexes, an animal that is a hermaphrodite has the advantage of _____. a. being able to reproduce during times of stability or stress b. using less energy to produce gametes c. producing offspring with greater genetic variability d. mating with any other member of its species

d

Complex fire/don't fire "decision making" by neurons is most directly a result of the fact that __________. a. action potentials of various sizes can sum to a threshold potential b. chemical transmission allows signals to be transmitted in both directions across a synapse c. excitatory neurotransmitters cause positive action potentials and inhibitory neurotransmitters cause negative action potentials d. neurons receive a combination of signals from both excitatory and inhibitory synapses

d

How do ovulated oocytes get into the uterus? a. Because ovaries are within the uterus, the ovulated egg is already within the uterus. b. Fimbriae sweep over the oviduct. c. The oocyte actively swims through the oviduct, using its flagellum. d. Cilia within an oviduct create currents that sweep the egg toward the uterus.

d

On its way to fertilize a human egg, a sperm cell does not have to pass through which of the following? a. cervix b. oviduct c. vagina d. ovary

d

Part complete Which of the following statements is FALSE? a. As a signal travels down a myelinated axon, the signal jumps from one node of Ranvier to the next node of Ranvier. b. A neuron typically has many more dendrites than axons. c. The myelin sheath limits the points where signals can be transmitted along the length of an axon. d. Most of the nervous system consists of neurons.

d

The threshold potential is of great significance in the physiology of neurons because if the threshold potential is not reached, _____. a. the action potential will be "inversed," with a flux of sodium out of the cell rather than into it b. the neuron cannot regain its resting potential c. an action potential will be reached d. an action potential will not occur

d

What causes an action potential to be conducted along a neuron's axon? a. The change in charge difference across the membrane spreads from open potassium channels, causing sodium channels farther along the axon to open. b. The axon returns to its resting potential. c. The change in charge difference across the membrane spreads from open potassium channels, causing potassium channels farther along the axon to open. d. The change in charge difference across the membrane spreads from open sodium channels, causing sodium channels farther along the axon to open. e. The change in charge difference across the membrane spreads from open sodium channels, causing the sodium-potassium pumps to move ions across the neuron's membrane.

d

When calcium ions enter the synaptic terminal, a. the inside of the receiving neuron becomes more positive. b. the inside of the receiving neuron becomes more negative. c. they cause an action potential in the sending neuron. d. neurotransmitter molecules are quickly removed from the synaptic cleft. d. they cause vesicles containing neurotransmitter molecules to fuse to the plasma membrane of the sending neuron.

d

Where are you less likely to find complete semen (in which all the components are present)? a. at the junction of the bulbourethral duct and the urethra b. in the urethra c. in the vagina of a woman who's trying to become pregnant d. in the epididymis

d

Which of the following best describes a nerve signal? a. the flow of neurotransmitter chemicals along a neuron b. the movement of tiny filaments of protein inside a neuron c. the flow of electricity along a neuron d. the passage of ions through the membrane of a neuron

d

Which of the following events does NOT occur during human fertilization? a. Acrosomal enzymes break down the zona pellucida. b. The DNA of the sperm unites with the DNA of the egg. c. Receptors on the sperm bind to the zona pellucida surrounding the egg. d. Enzymes on the outside of the sperm break down the follicle cells surrounding the egg

d

Which of the following statements about the resting potential state of a neuron is true? a. The concentration of sodium is much higher inside the cell than outside. b. The neuron's plasma membrane is much less permeable to potassium than to sodium. c. The sodium-potassium pump plays a role in pushing sodium ions into the cell, causing depolarization. d. The membrane potential can change from its resting value if the membrane's permeability to particular ions changes.

d

Which of these causes the release of neurotransmitter molecules? a. the receipt of a signal from the postsynaptic neuron b. the opening of voltage-regulated calcium channels and the diffusion of calcium ions out of the neuron c. an action potential reaching the end of the cell body d. an action potential reaching the end of the axon e. an action potential reaching the end of the dendrite

d

A nerve impulse moves toward a neuron's cell body along _____.

dendrites

In neurons, ____________ receive signals and ____________ transmit signals.

dendrites; axons

If there is fertilization, secretion of _____ by the early embryo maintains the corpus luteum. a. progesterone b. estrogen c. luteinizing hormone d. follicle-stimulating hormone e. human chorionic gonadotropin

e

Neurons store neurotransmitter molecules in vesicles located within _____. a. the cell body b. myelin c. the synaptic cleft d. dendrites e. synaptic terminals

e

Sperm become capable of movement while in the _____. a. seminiferous tubules b. vas deferens c. ejaculatory ducts d. urethra e. epididymis

e

The onset of menstruation is triggered by __________. a. a sudden increase in the levels of b. progesterone and FSH c. a drop in the levels of FSH and LH d. a drop in the level of estrogen e. a drop in the levels of progesterone and estrogen

e

Which pituitary secretion stimulates sperm production? a. LH b. ACTH c. TSH d. PRL e. FSH

e

A cluster of nerve cell bodies outside the central nervous system is referred to as a(n) _____.

glanglion

Axons insulated by a(n) _____ are able to conduct impulses faster that those not so insulated.

myelin sheath

Schwann cells make up the...

myelin sheath

The cell that conducts an action potential in the nervous system is a(n) _____.

neuron

A molecule that carries information across a synaptic cleft is a

neurotransmitter

An impulse relayed along a myelinated axon "jumps" from _____ to _____.

node of Ranvier ... node of Ranvier

Sodium-potassium pumps

restore the distribution of ions inside and outside a neuron's membrane following an action potential.

The small space between the sending neuron and the receiving neuron is the

synaptic cleft

What part of a neuron relays signals from one neuron to another neuron or to an effector?

synaptic terminal

True or false. During sperm maturation, secondary spermatocytes are the products of meiosis II that go on to form spermatids, which undergo restructuring to form spermatozoa. True False

False