Upgrade to remove ads
BSC Exam 4
Terms in this set (256)
which of the following would an organism need to adjust blood pressure independently in the blood vessels of the gas-exchange surface and in the blood vessels of the general body circulation?
the velocity of blood flow lowest in capillaries because ___________.
the total cross-sectional area is greater in the capillaries than in any other part of the circulatory system.
You feel something touch your arm, think it might be a fly, and you extend your arm to scare it away. In which order is the information about the touch processed?
sensory input, integration, and motor output
a nerve is a collection of _______.
which of the following structures is involved in the human knee-jerk reflex?
damage to the external intercostal muscles, which are located between the ribs and function to help expand the chest cavity, will likely directly result in difficulty with which of the following function?
regulation of blood pressure
which biological membranes must atmospheric molecules of oxygen cross to become bound to hemoglobin for transport in mammals?
five membranes (in and out of the cell lining the lung, in and out of the endothelial cell lining and alveolar capillary, and into the red blood cell)
which type of circulatory system is most likely present in organisms with a circulating body fluid that is distinct from the fluid that directly surrounds the body's cells?
a closed circulatory system
which of the following are the only vertebrates in which blood flows directly from respiratory organs to body tissues without first returning to the heart?
which of the following is most analogous in structure and function to the circulatory systems of bony fishes, rays, and sharks?
the portal systems of mammals, where two capillary beds occur sequentially, without passage of blood through a pumping chamber
the human respiration rate is most closely correlated to the blood levels of which compound during most daily activities?
what is a person's total lung capacity if they have a tidal volume of 450 mL, a vital capacity of 4,000 mL, and a residual volume of 1,000 mL?
What is the correct sequence of blood flow in birds and mammals?
vena cava-->right atrium-->right ventricle-->pulmonary artery
respiratory acidosis is a condition that can result from decreased ventilation rates (hypoventilation). If a sign of respiratory acidosis is decreased blood pH, what is likely true about the blood in the body?
there is more CO2 in the blood
which of the following organisms has no specialized respiratory structures?
*earthworms respire through the skin surface.
what is the function of a circulatory system?
it brings a transport liquid into close contact with all cells in the body.
*this transport liquid exchanges gases, nutrients, and wastes with the cells in the body.
why do the circulatory systems of land vertebrates have separate circuits to the lungs and the rest of the body?
the large decrease in blood pressure as blood moves through the lungs may prevent efficient circulation through the rest of the body.
T or F? the circulatory systems of land-dwelling vertebrates are composed of two pumping circuits: the systematic circulation, which is a lower-pressure circuit to the lung, and the pulmonary circulation, which is a higher-pressure circuit to the rest of the body.
*the pulmonary circulation is the lower-pressure circuit to the lung, whereas the systemic circulation is the higher-pressure circuit to the rest of the body.
What is the function of the left ventricle?
it pumps oxygenated blood around the body via the systemic circulation.
*the left ventricle receives oxygenated blood from the lungs and pumps it to the rest of the body.
T or F? valves prevent the back flow of blood into the atria and ventricles?
what event occurs first during atrial and ventricular diastole?
the atria and ventricles are relaxed, and blood flows into the atria.
________________ is the relaxation phase of the cardiac cycle during which the chambers of the heart are relaxed and blood can enter them passively.
Which event of the cardiac cycle occurs when systolic blood pressure is measured?
the ventricles contract, carrying blood into the aorta, and blood flows into the relaxed atria.
the ____________ __________ _____________ is the peak blood pressure, resulting from contraction of the ventricles.
systolic blood pressure
blood returns to the heart via the ______________.
what carries oxygenated blood from the lungs to the left atrium?
from the pulmonary veins, blood flows to the ___________.
from the superior vena cava, blood flows to the _________.
from the capillaries of the abdominal organs and hind limbs, blood flows to the _____________.
inferior vena cava
which type of blood vessel has the greatest total cross-sectional area throughout the whole body?
what is the effect of total cross-sectional area on the velocity of blood flow?
vessels with higher total cross-sectional area have lower blood velocity
rank the following blood vessels from lowest blood pressure to highest blood pressure:
venae cavae, veins, capillaries, arterioles, aorta
T or F? blood flowing from one aorta into billions of capillaries decreases the velocity and pressure of the blood flow.
T or F? blood flow is at its highest velocity in the venae cavae.
T or F? blood flows from an area of low pressure to an area of high pressure.
T or F? blood flow velocity is inversely related to cross sectional area.
T or F? as blood flows from the aorta through the other vessels, blood pressure increases.
T or F? the lowest velocity of blood flow occurs in the capillaries.
what is the direct cause of demineralization of the enamel on teeth?
acids produced by bacteria
what is the direct cause of gum disease?
plaque formed by bacteria
T or F? there is a correlation between periodontal disease and heart disease.
People who produce very little saliva often have more cavities. What is the best explanation for this?
since saliva normally helps neutralize acid and replace minerals on teeth, a lack of saliva leads to more cavities.
dentists sometimes give a patient antibiotics after a teeth-cleaning procedure, especially if the patient is older or has heart disease. What is the best explanation for this?
antibiotics help kill the bacteria that move from the mouth to the bloodstream, and prevent the bacteria from contributing to atherosclerosis.
voice sounds are produced by the _________.
the primary functions of the __________ are to warm, filter, and humidify air.
The incorporation of CO2 into bicarbonate ions in red blood cells roughly follows this three step process:
1. CO2 reacts with water and forms carbonic acid, a reaction catalyzed by the enzyme carbonic anhydrase.
2. Each molecule of carbonic acid (H2CO3) dissociates into a bicarbonate ion (HCO3-) and a proton (H+).
3. Most of the bicarbonate ions diffuse into the blood plasma.
T or F? The lungs of humans form from the embryonic foregut.
*digestive organs such as the stomach and part of the small intestine also develop from the foregut.
T or F? the pressure inside the human chest cavity is always positive, so the lungs stay relatively inflated even upon exhalation.
*The lungs stay relatively inflated even upon exhalation because the pressure inside the chest cavity is always negative.
Which lung structure is a tiny sac that functions as an interface between air and blood?
Which barrier(s) must O2 and CO2 cross to pass between air and blood inside the lungs?
epithelial cells, extracellular fluid, and capillary wayy
How is most carbon dioxide transported from tissues to the lungs?
as bicarbonate ions (HCO3^-)
What is cooperative binding?
the binding of one oxygen molecule to hemoglobin stimulates the binding of other oxygen molecules.
T or F? Innate immunity is the first, and most general, mechanism of protection against pathogens.
which response is triggered when bacteria enter the body through a small cut in the skin?
activation of a group of proteins called complement
acidity in human sweat is part of which type of immune system?
A phagocytic cell has a mutation in a gene for a hydrolytic enzyme that renders the enzyme nonfunctional. What is the most likely effect of the mutation when this phagocytic cell ingests a pathogen?
the lysosome will not degrade the pathogen effectively
which option best describes why Jenner's use of cowpox virus as a vaccine against the smallpox virus was successful?
there are some epitopes (antigenic determinants) common to both pox viruses
Which of the following best explains why a bone marrow transplant may not be appropriate from a given donor to a given recipient even though they are compatible for blood transfusions?
their blood types may match but major histocompatibility (MHC) proteins may not be a match
Some people are allergic to dust mites, which are tiny insects that commonly live in house dust. What is the most immediate outcome if someone who is allergic to dust mites inhales dust years after they are first exposed to dust mites?
IgE antibodies bound to mast cells bind the dust mite allergen
Which of the following cells and signaling molecules are involved in the initial stages of the inflammatory response?
lymphocytes and interferons
dendritic cells and interferons
mast cells and histamines
phagocytes and cytokines
mast cells and histamines
what protects both the eyes and the respiratory tract against infections?
the secretion of lysozyme onto their surfaces
Which statement correctly describes both CD4 and CD8 proteins?
-molecules present on the surface of T cells that interact with major histocompatibility (MHC) molecules.
-secreted by antigen-presenting cells.
-receptors present on the surface of natural killer cells.
-molecules on the surface of antigen-presenting cells where they enhance B cell activity.
molecules present on the surface of T cells that interact with major histocompatibility (MHC) molecules
Which secretion is not a barrier that prevents pathogens from entering the body?
what are foreign molecules that initiate an immune response?
T or F? the leukocytes of the innate immune system are B cells, macrophages, and neutrophils.
what are the leukocytes of the innate immune system?
mast cells, macrophages, and neutrophils
How do cells involved in the innate immune response detect the presence of pathogens?
leukocytes recognize unique molecules on pathogens.
What are leukocytes that can engulf and digest a pathogen?
What is the role of mast cells in the inflammatory response?
they release chemicals that dilate blood vessels near the wound site, allowing blood components to enter the region from the blood stream.
what occurs first when a wound that breaks the skin has occurred?
platelets release proteins that form clots and decrease bleeding.
T or F? the site of inflammation may become swollen due to the increased numbers of cells and fluids at the site and painful due to signals from pain receptors.
_____________ interact with the antigen-class II MHC complex presented by macrophages.
helper T cells
B cells that have been stimulated by interleukin-2 develop into ___________.
the role of cytotoxic T cells is the secretion of ___________, which plays a role in the _____________ immune response.
clonal selection is the division of __________ that have been stimulated by binding to an antigen, which results In the production of cloned _______________.
B cells...plasma cells and memory cells
which cells are responsible for the rapidity of the secondary immune response and for long-term immunity?
what cells produce and secrete antibodies?
*plasma cells are clones of antibody-secreting B cells
What is the final step in the cell-mediated response to a viral infection?
cytotoxic T lymphocytes punch holes in the membranes of infected host cells
How do cells involved in the humoral response respond to antigen presentation on the surface of a B cell?
Helper T cells recognize the receptor-antigen complex and cause plasma and memory cells to be produced to then produce antibodies.
What protein presents viral antigens on the outer surface of cells?
how are cytotoxic T lymphocytes (CTLs) produced?
CD8+ T cells divide and differentiate into cytotoxic T lymphocytes
each person makes more than 1 million different B cell antigen receptors and more than 10 million different T cell antigen receptors. How is such diversity in antigen receptors generated?
by combining variable elements, the immune system assembles many different receptors from a much smaller collection of parts.
T or F? The words "antigen" and "virus" are interchangeable.
*A virus, like other pathogens, has numerous antigens on its surface, so the words antigen and virus cannot be used interchangeably.
A man who has been exposed to the flu virus is tested by his physician. The physician notes that the virus is present but no measurable level of antibodies corresponding to the virus are detected in his body.
What might this mean?
He was probable exposed a few days ago and clonal selection has yet to produce plasma cells.
T or F? Memory cells have a longer lifespan than plasma cells.
*Plasma cells only live 4-5 days, but memory cells may last for decades
what is an advantage of excreting nitrogenous wastes as urea rather than as ammonia?
urea is less toxic than ammonia
The structural component(s) of the mammalian nephron where increased permeability to water occurs due to the action of anti-diuretic hormone is/are the _____________.
anti-diuretic hormone action leads to increased numbers of ______________ in the walls of the collecting ducts.
Which statement best describes the transfer of fluid from the glomerulus to Bowman's capsule?
blood pressure in the capillaries of the glomerulus causes transfer to occur
the body fluids of an osmoconformer would be _________ with its __________ environment.
You just received a freshwater aquarium as a gift and decide to add more fish. When you get to the pet store, you find that the most beautiful fish are saltwater animals, but you decide to buy them anyway. What will happen when you put your saltwater fish in your freshwater aquarium?
the cells of the fish will take up too much water and the fish will die
An increase in protein kinase A activity in all cells of the collecting duct cells will most likely have which effect on kidney function?
more-concentrated urine will be produced
What process must freshwater fish undertake to maintain homeostasis?
excrete large quantities of water
compared to the seawater around them, most marine invertebrates are ___________.
Which stimuli is most likely to increase secretion of antidiuretic hormone (ADH)?
Excessive formation of uric acid crystals in humans leads to what medical condition?
gout, a painful inflammatory disease that primarily affects the joints
What are paired organs that regulate water and electrolyte balance in terrestrial vertebrates, and also remove nitrogenous wastes from the blood and eliminate them in the urine?
what is the basic functional unit fo the kidney?
what is the correct sequence of flow through the nephron?
renal corpuscle; proximal tubule; loop of Henle; distal tubule; collecting duct
what is the driving force for the filtration of blood by the renal corpuscle?
higher pressure in glomerular capillaries than in the surrounding Bowman's capsule
which regions of the nephron function independently of hormonal control for the most part?
renal corpuscle, proximal tubule, and loop of Henle.
in which region of the nephron is a steep osmotic gradient created?
loop of Henle
What causes the collecting duct to increase water reabsorption by the surrounding tissue under conditions of dehydration?
the __________ transports urine from the urinary bladder to the world outside the body.
urine formed by a kidney collects in the ____________ before being drained from the kidney by the ________ and transported to the _____________.
renal pelvis; ureter; urinary bladder
fluid from the glomerulus first collects in the _____________.
the __________ are the major blood vessels transporting blood to the kidneys.
the outer part of the kidney is the _________.
under the influence of antidiuretic hormone (ADH), _________ is produced.
more concentrated urine
ADH makes the __________ permeable to water.
birds, insects, and many reptiles excrete nitrogenous wastes in the form of uric acid, which _______________.
reduces water loss compared to other nitrogenous wastes, but requires more metabolic energy to produce
which of the following is reabsorbed in the proximal tubule, leading to a reduction in the overall filtrate volume?
solutes and water
which of the following characteristics describes the thin segment of the ascending limb of the loop of Henle?
-permeable to H2O, impermeable to NaCl.
-impermeable to H2O and NaCl
-permeable to H2O and NaCl
-impermeable to H2O, permeable to NaCl
impermeable to H2O, permeable to NaCl
In which section of the nephron does the filtrate have a higher osmolarity than the blood when it enters and lower osmolarity than the blood when it leaves?
ascending limb of the loop of Henle
what contributes most significantly to the kidney's high energy expenditure?
transport of NaCl in the thick segment of the ascending limb of the loop of Henle
T or F? the collecting duct becomes more permeable to water when the kidneys are in water-conservation mode.
T or F? the collecting duct concentrates urine by actively reabsorbing NaCl.
T or F? regulated changes in the epithelium of the loop of Henle allow the kidney to operate in water-conservation mode.
T or F? reabsorption of water and solutes in the proximal tubule reduces the volume of the filtrate.
A certain hormone activates the cAMP second messenger system in its target cells. Which of the following would yield the greatest response by a target cell?
apply the hormone to the extracellular fluid surrounding the cell
which hormone regulates skin color in fishes, amphibians, and reptiles?
which of the following functions would most likely be disrupted by an injury to the hypothalamus?
regulation of water balance
hormones are ___________.
chemical signals between cells, transported in blood or hemolymph.
what two hormones, in a lactating mammal, promote milk synthesis and milk release, respectively?
prolactin and oxytocin
where are oxytocin and antidiuretic hormone (ADH) produced and transported to?
produced in the neurosecretory cells of the hypothalamus and transported to the posterior pituitary gland
T or F? the hypothalamus and anterior pituitary contain capillary beds connected by portal blood vessels.
Which of the following glands produces hormones that affect osmoregulation, reproduction, and metabolism?
Negative feedback by a steroid at all levels of the hypothalamus-anterior pituitary-adrenal cortex stress response implies that each of these components has receptors for __________.
Which of the following is the most likely outcome of a reduction of blood flow in the portal system connecting the hypothalamus and the pituitary gland?
reduced levels of growth hormone in the blood
what is the function of endocrine glands?
they release hormones into the bloodstream for distribution around the body.
T or F? the homeostatic system for blood calcium concentration is maintained by the hormones calcitonin and parathyroid hormone.
T or F? the pancreas is responsible for producing hormones that maintain the homeostatic levels of glucose in the blood.
how is the production of hormones such as thyroxine and estrogen regulated?
the hypothalamus directs the anterior pituitary to produce hormones that then stimulate or inhibit the production of these hormones
_____________ produced by the adrenal glands controls the reabsorption of sodium ions by the kidneys.
Gigantism, a condition characterized by exceptionally rapid growth, is sometimes caused by a tumor that induces the gland in which it develops to overproduce a certain hormone. Where would such a tumor be expected to grow?
Which of these extracellular signal molecules could diffuse through a plasma membrane and bind to an intracellular receptor?
*steroid hormones such as estrogen can diffuse through the plasma membrane and bind to intracellular receptors.
the primary reason steroid hormones usually act slowly is that _____________.
they turn genes on or off and it takes time for gene products to build up or become depleted
steroid hormone-receptor complexes act in ____________.
which type of hormone is lipid soluble?
which molecules determine the tissue specificity of hormones?
T or F? lipid-soluble hormones act by affecting the transcription of genes.
A _______________ is a distinctive DNA-binding domain on some hormone receptors that is exposed when hormone-receptor complexes are formed.
what is the role of cAMP in the signal transduction pathway activated by epinephrine?
it binds to and activates protein kinase A, which then phosphorylates other enzymes
what synthesizes oxytocin and ADH, and integrates nervous and endocrine systems?
what releases oxytocin and ADH, and is an extension of the hypothalamus?
what synthesizes and releases PRL, is regulated by hormones released into portal blood vessels, and synthesizes and releases TSH?
what hormones are responsible for the fight or flight response to danger?
epinephrine and norepinephrine
adrenocorticotropic hormone (ACTH) triggers the release of __________ in response to stress.
_____________ are the main male hormones.
what hormone promotes water retention by the kidneys?
antidiuretic hormone (ADH)
which hormone opposes the action of parathyroid hormone?
which hormone stimulates hormone production by the ovaries and testes?
luteinizing hormone (LH)
which hormone stimulates milk production?
T or F? Epinephrine functions as a hormone in the endocrine system and as a neurotransmitter in the nervous system.
In humans, oogenesis in comparison to spermatogenesis is different in that ________________.
oogenesis does not complete meiosis until after fertilization, but spermatogenesis is complete before the sperm leave the body
pheromones used in reproduction are not likely to be found in organisms that only reproduce ______________.
what is an advantage of sexual reproduction over asexual reproduction?
results in greater genetic diversity in offspring
when is asexual reproduction more likely to result in greater reproductive success than sexual reproduction?
when a species is in a stable and favorable environment
an inactivating mutation in the progesterone receptor gene would likely result in _______________.
the inability of the uterus to support pregnancy
Many aphid species switch between asexual and sexual reproduction. Which of the following is only used during sexual reproduction?
A pregnant woman comes into the hospital past her due date. The doctor decides it is time for the baby to be delivered. Which hormone could the doctor use to induce labor?
Human pregnancy is indicated by the presence of chorionic gonadotropin metabolites in the urine until __________.
the placenta takes over for the ovaries in producing the steroid hormones needed during pregnancy
which hormone is released from Sertoli cells and inhibits the release of follicle stimulating hormone?
humans form gametes by ___________.
what role do germ cells play in gametogenesis?
they produce cells that divide by mitosis and then undergo meiosis to form gametes.
what products are formed when a diploid cell undergoes meiosis?
four haploid cells
T or F? beginning at puberty, a primary oocyte completes its first meiotic division to form a secondary oocyte and a polar body approximately every month in humans.
which diploid cells are produced by an embryonic germ cell?
*these are male diploid cells that are produced by embryonic germ cells
how does spermatogenesis differ from oogenesis?
diploid cells give rise to four functional gametes in spermatogenesis
a fertilized egg usually implants itself and develops in the _______.
a rapid increase in the _____________ level stimulates ovulation.
after ovulation, high levels of _____________ inhibit __________ secretion.
estrogen and progesterone.....FSH and LH
developing ovarian follicles primarily secrete _____________.
if there is fertilization, secretion of ____________ by the early embryo maintains the corpus lute.
human chorionic gonadotropin
if there is no fertilization, degeneration of the corpus lute results in a drop in ______________, which results in the sloughing off of the uterus's endometrium.
estrogen and progesterone
ovulation usually occurs on or about day ___________ of a 28-day ovarian cycle.
what is the usual site of the fertilization of an egg cell?
sperm become mature and capable of movement while in the ____________.
The secretion of androgens is regulated by a _____ feedback mechanism involving the _____ and _____.
Which hormone(s) is(are) directly responsible for triggering the development of the secondary sex characteristics of males, such as beard growth?
Which pituitary secretion stimulates sperm production?
Which pituitary secretion stimulates the testes to secrete androgens?
sperm develop in the ____________.
a human oocyte only completes meiosis II after ____________.
the first stage of embryonic development is ___________. This process produces __________.
cleavage....a cluster of cells
____________ and ___________ are developmental stages that follow cleavage.
Release of the acrosomal contents during fertilization most directly results in which of the following events?
digesting the protective jelly coat on the surface of the egg
what is the correct developmental sequence of animal development?
fertilization, cleavage, gastrulation, organogenesis
which of the following outcomes would most likely occur if gastrulation was blocked?
embryonic germ layers would not form
Which of the following is most likely to occur if an amphibian zygote is manipulated so that the first cleavage plane fails to divide the gray crescent?
only the daughter cell with the gray crescent will develop normally
what is common to the development of birds and mammals?
the formation of an embryonic epiblast and hypoblast
Which of the following correctly describes gastrulation in frog embryos?
proceeds by involution as cells roll over the lip of the blastopore
In animal development, which of the following best describes the process of cleavage?
what are the cells created by cleavage called?
what are the three germ layers contained in the gastrula?
ectoderm, mesoderm, endoderm
what happens to a cell during the process of differentiation?
it undergoes a change toward a more specialized form or function
in sea urchins, the process of fertilization produces a(n) _________.
what is the cortical reaction?
the formation of a fertilization envelope that bars additional sperm from entry into the egg
as cleavage continues, a zygote forms into a solid, multicellular ball called a __________.
the ___________ eventually develops into the sea urchin's digestive tract.
During gastrulation in frogs, a rod of mesoderm under the dorsal surface forms the _____.
During gastrulation in frogs, cells from the animal pole spread over the embryo and form the _____.
The notochord functions as a core around which mesodermal cells form the frog's _____.
an ectodermal thickening above the frog's notochord forms a _________.
The _____ is(are) formed when the neural folds join and a portion of the neural plate sinks beneath the embryo's surface.
The enlarged anterior portion of the neural tube will develop into a frog's _____.
The posterior portion of the neural tube will develop into the frog's _____.
The allantois stores nitrogenous wastes in a reptile egg. What is the function of the allantois in human development?
the allantois helps form the umbilical cord in human development
Which of the following would most likely occur if you experimentally depolarize the middle of an axon to threshold using an electronic probe?
two action potentials will be initiated and will proceed in opposite directions
Which answer explains why Na+ ions enter the cell when voltage-gated Na+ channels are opened in neurons?
he Na+ concentration is much higher outside the cell than it is inside, and the Na+ ions are attracted to the negatively charged interior
If a pebble is tossed into a pond, it generates small ripples that decrease in size as the ripples move away from the point where the pebble struck the water. The decreasing size of the ripples as they move away from the initial splash is most like the way that signals spread ________.
in a graded potential
the information receiving section of a neuron is its ___________.
cell body and dendrites
Which of the following will induce a graded hyperpolarization of a membrane under normal resting conditions?
increasing its permeability to K+
In which location would we expect to find the release of neurotransmitter molecules?
in a chemical synapse
describe the axons of neurons with the fastest conduction velocity for action potentials.
wider, myelinated axons
At the neuromuscular junction, the binding of acetylcholine to receptors on the muscle cell almost immediately causes __________.
a graded depolarization
Acetylcholine released into the junction between a motor neuron and a skeletal muscle binds to a sodium/potassium channel and opens it. This is an example of ________.
a ligand-gated channel
What would most likely happen if twice as many inhibitory postsynaptic potentials (IPSPs) as excitatory postsynaptic potentials (EPSPs) arrive in close proximity at a postsynaptic neuron?
no action potential
Ions move in the direction opposite to that favored by the chemical concentration gradient when _____.
they are pumped by proteins that require ATP hydrolysis and when the electrical charge gradient repulses or attracts them
A nerve impulse moves toward a neuron's cell body along _____.
A nerve impulse moves away from a neuron's cell body along _____.
An impulse relayed along a myelinated axon "jumps" from _____ to _____.
node of Ranvier....node of Ranvier
Axons insulated by a(n) _____ are able to conduct impulses faster than those not so insulated.
What type of cell makes up the myelin sheath of a motor neuron?
what part of a neuron relays signals from one neuron to another neuron or to an effector?
Which term describes the difference in electrical charge across a membrane?
Resting neurons are most permeable to which of the following ions?
the potential energy of a membrane potential comes from what?
both the difference in electrical charge and from the concentration gradient of ions across a membrane
which channel is mainly responsible for the resting potential of a neuron?
potassium leak channel
Which term describes an electrical signal generated by neurons?
Which membrane protein maintains the concentration gradients of ions across a neuronal membrane?
the sodium-potassium pump moving Na+ ions out and K+ ions in
What behavior is observed if the voltage across a neuronal membrane is set to -20 mV?
the sodium channel opens, and Na+ ions flow in
sodium ions flow into the cell when the membrane potential is between ______________.
-20 mV and 30 mV
Which event triggers the creation of an action potential?
the membrane depolarizes above a certain threshold potential
Which of the following terms describes how a neuronal membrane's potential is altered in the presence of inhibitory signals?
where in the neuron do action potentials begin?
How is an action potential propagated down an axon after voltage-gated sodium channels open in a region of the neuron's membrane?
Sodium ions enter the neuron and diffuse to adjacent areas, resulting in the opening of voltage-gated sodium channels farther down the axon
A neuron has a resting potential of about _____ millivolts.
An action potential moves along a(n) _____.
At rest, which of these plays a role in establishing the charge differential across a neuron's plasma membrane?
the sodium-potassium pump moving sodium ions out of the neuron and potassium ions into the neuron
The transmission first triggers the _____.
opening of voltage-gated sodium channels and the diffusion of sodium ions into the neuron
A stimulus has opened the voltage-gated sodium channels in an area of a neuron's plasma membrane. As a result, _____ rushes into the neuron and diffuses to adjacent areas; this in turn results in the _____ in the adjacent areas.
sodium ... opening of voltage-gated sodium channels
If the membrane potential of a neuron decreases, the membrane potential _____.
becomes less negative
How do the brains of birds and mammals compare to other groups of vertebrates?
The ratio of brain size to body weight for birds and mammals is about ten times greater than other groups of vertebrates
What do we call the point of connection between two communicating neurons?
Addiction onset by cocaine and amphetamines is characterized by increased __________.
persistence of dopamine in the brain's synapses
In which part of the brain is hunger and thirst regulated?
Motor cortex and somatosensory cortex are __________.
organized in similar manner adjacent to each other, and are anatomically similar from one person to the next
The telencephalon region of the developing brain of a mammal ________.
gives rise to the cerebrum
Which of the following results from increased activity in the sympathetic nervous system?
heart rate decreases
glucose is converted to glycogen
digestion is inhibited
epinephrine secretion is inhibited
digestion is inhibited
Which of the following types of organisms is most likely to have a nerve net?
Which of the following structures is involved in the human knee-jerk reflex?
The fundamental excitable cell in the nervous system is the _____.
As vertebrates evolved, the increasingly complex structure of the brain conferred increasingly complex function, especially apparent in the __________.
cerebral cortex, which is greatly expanded in nonhuman primates and cetaceans
Activation of the parasympathetic branch of the autonomic nervous system __________.
what does the medulla oblongata control?
You might also like...
chapter 19 practice questions and answers
Blood Vessels and Circulation
Other sets by this creator
EN 209 Final Exam
EN 209 Midterm
BSC Exam 5
BIO EXAM 3: Ch. 32, 33, 34, 40, 41
Other Quizlet sets
Chapter 10 review questions
Physiology Digestive System Class Questions
Foodborne Illnesses too