Bio 240 Mastering Biology
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.
When the body's blood glucose level rises, the pancreas secretes insulin and, as a result, the blood glucose level declines. When the blood glucose level is low, the pancreas secretes glucagon and, as a result, the blood glucose level rises. Such regulation of the blood glucose level is the result of _____. -catalytic feedback -negative feedback -protein-protein interactions -positive feedback
Negative feedback
All animals, whether large or small, have _____. -a basic body plan that resembles a two-layered sac -a body surface covered with hair to keep them warm -an external body surface that is dry -most of their cells in contact with an aqueous medium
Most of their cells in contact with an aqueous medium
True or false? Organisms must maintain homeostasis because optimal enzyme activity is achieved within a very narrow range of conditions.
True- enzyme activity depends on conditions within a cell, such as temperature and pH, which must be kept within a certain narrow range.
Which of the following statements about blood circulation in the body is true?
Valves prevent the backflow of blood into the atria and ventricles- valves are flaps of tissue that close when the ventricles contract to prevent the backflow of blood into the atria and also when the ventricles relax to prevent the backflow of blood from exiting vessels to the ventricles.
Chum salmon (Oncorhynchus keta) are born in freshwater environments and then migrate to the sea. Near the end of their lives, they return to the freshwater stream where they were born to spawn. In freshwater, water constantly diffuses into the body and ions are lost from the body. In salt water, body water diffuses out of the body and excess ions are gained from the water. A salmon's gills have special cells to pump salt in or out of the body to maintain homeostasis. In response to the salmon's moves between freshwater and salt water, some cells in the gills are produced and others are destroyed. These changes made in the cells of the gills during the lifetime of an individual salmon are an example of which of the following? -acclimatization -evolution -adaptation -trade-off
Acclimatization
Which of the following statements describes a negative feedback response? -The arrival of platelets at a wound site stimulates the recruitment of more platelets to form a clot. -The onset of contractions during childbirth stimulates the release of a hormone that stimulates further contractions. -After a meal, blood sugar levels in the body rise; insulin is secreted to lower blood sugar levels. -A person who loses 3 pounds continues to diet to lose an additional 10 pounds.
After a meal, blood sugar levels in the body rise; insulin is secreted to lower blood sugar levels- the actions of insulin reverse the internal conditions of high blood sugar levels in the body.
Which of these is an example of negative feedback? -As a blood clot begins to form, the process of its formation gets faster and faster. -After you eat, glucagon stimulates an increase in blood sugar levels. -After you eat, insulin stimulates the lowering of blood sugar levels. -The digestive enzyme pepsinogen is converted to pepsin by the action of hydrochloric acid; pepsin itself can then convert pepsinogen into pepsin. -Once labor begins, contractions increase in frequency and intensity.
After you eat, insulin stimulates the lowering of blood sugar levels- eating raises blood sugar levels; insulin stimulates the lowering of blood sugar level. In this example the response to the stimulus (increased blood sugar levels) opposes that stimulus (by lowering blood sugar levels).
Which of the following actions is not a function of the epithelium? -Allows the internal environment to alter its conditions to match those of the external environment. -Controls the exchange of nutrients between the internal and external environments. -Regulates the excretion of waste. -Creates an internal environment that is different from the external environment.
Allows the internal environment to alter its conditions to match those of the external environment- the epithelium allows the internal environment to remain constant even if the external environment changes.
_____ in carbon dioxide in your red blood cells, which causes _____ in pH, causes your breathing to speed up.
An increase ... a drop- water and carbon dioxide combine, in the presence of the enzyme carbonic anhydrase (found inside red blood cells), to form carbonic acid, which dissociates to hydrogen ion and bicarbonate. The higher concentration of hydrogen ions leads to a drop in pH.
Blood pressure is highest in the _____. -aorta -inferior vena cava -superior vena cava -pulmonary artery -capillaries
Aorta- carries blood that has just left the left ventricle, has the highest blood pressure.
Cartilage is found _____. -surrounding organs such as the kidneys -in the heart -at the ends of bones such as the femur -covering the surface of your body -connecting one bone to another
At the ends of bones such as the femur- the ends of long bones, such as the femur, have a cartilage cap.
Arteries carry blood _____.
Away from the heart only
Why does the velocity of blood slow greatly as blood flows from arterioles into capillaries?
Because capillary beds have a total cross-sectional area much greater than the total cross-sectional area of the arterioles- the cross-sectional area is much greater in capillary beds than in the arteries or any other part of the circulatory system, there is a dramatic decrease in velocity from the arteries to the capillaries. Blood travels 500 times slower in the capillaries (about 0.1 cm/sec) than in the aorta (about 48 cm/sec). Read about blood flow velocity.
Which of these is NOT one of the four major categories of tissue? -muscle -epithelial -connective -blood -nervous
Blood- it is a connective tissue
_____ is the connective tissue specialized for transport. -Bone -Blood -Adipose tissue -Muscle tissue -Cartilage
Blood- specialized for the transport of substances such as nutrients, wastes, and gases.
Cardiac muscle is the only muscle composed of _____ fibers. -branched -unstriated -unbranched and cylindrical -spindle shaped -striated
Branched- Cardiac muscle fibers are branched.
The smallest airway through which inspired air passes before gas exchange occurs in the mammalian lungs is the _____.
Bronchiole- give rise to the alveoli, the site of gas exchange.
Carbon dioxide enters the blood at the _____. -capillaries of the lungs -capillaries of the abdominal organs -capillaries of the hind limbs -capillaries of the head and forelimbs -capillaries of the head, forelimbs, abdominal organs, and hind limbs
Capillaries of the head, forelimbs, abdominal organs, and hind limbs- in these capillaries oxygen diffuses into, and carbon dioxide diffuses out of, body tissues
The _____ has(have) the thinnest walls. -aorta -capillaries -inferior vena cava -pulmonary artery -right ventricle
Capillaries- the thin walls of the capillaries facilitate gas exchange.
Most types of communication between cells utilize _____. -chemical or electrical signals -the exchange of DNA between the cells -the movement of the cells -the exchange of cytosol between the cells
Chemical or electrical signals
You discover a new species of bacteria that grows in aquatic environments with high salt levels. While studying these bacteria, you note that their internal environment is similar to the salt concentrations in their surroundings. You also discover that the internal salt concentrations of the bacteria change as the salt concentration in their environment changes. The new species can tolerate small changes in this way, but dies from large changes because it has no mechanism for altering its own internal salt levels. What type of homeostatic mechanism is this species using to regulate its internal salt levels? -conformation -regulation -integration -assimilation
Conformation
How does connective tissue differ from the other three major tissue types? -Connective tissue often consists of relatively few cells embedded in an extracellular matrix. -Connective tissue consists of contractile proteins. -Connective tissue consists of cells capable of transmitting electrical impulses. -There are three types of connective tissue. -Connective tissue is found lining body surfaces.
Connective tissue often consists of relatively few cells embedded in an extracellular matrix- this describes many connective tissues, such as loose connective tissue
A neuron consists of _____. -a cell body only -dendrites only -axons only -dendrites, a cell body, and axons -striations
Dendrites, a cell body, and axons- these are the three regions of a neuron.
Which of the following organisms has no specialized respiratory structures? -crabs -alligators -earthworms -ants -salmon
Earthworms- respire through the skin surface
If you gently bend your ear, and then let go, the shape of your ear will return because the cartilage of your ear contains_____. -elastic fibers -adipose tissue -collagenous fibers -reticular fibers
Elastic fibers
Environmental influences appear to contribute to cellular mutations that lead to tumor growth. For example, certain diets lead to higher incidence of colon cancers, and overexposure to sunlight leads to higher incidence of skin cancers. The tissues in closest contact with a carcinogen or mutagen (anything that causes genetic mutations) are obviously the ones most likely to develop tumors. Carcinomas and melanomas account for well over half of all cancers. What type of tissue would you guess the term carcinoma and melanoma is most closely associated with? -connective -epithelial -muscle -nervous
Epithelial
You are looking through a microscope at a slide of animal tissue and see a single layer of flat, closely packed cells that cover a surface. This specific tissue is most likely _____. -a neuron -a tendon -epithelial -adipose
Epithelial
Most of the exchange surfaces of multicellular animals are lined with _____. -smooth muscle cells -epithelial tissue -neural tissue -connective tissue
Epithelial tissue
True or false? The circulatory systems of land-dwelling vertebrates are composed of two pumping circuits: the systemic 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.
False- 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.
How does the dissociation curve for fetal hemoglobin compare to that for maternal hemoglobin?
Fetal hemoglobin has a higher affinity for oxygen than maternal hemoglobin at any partial pressure of oxygen- at any partial pressure of oxygen, the O2 saturation of fetal hemoglobin (red line) is higher than that for maternal hemoglobin (blue line).
Most gas exchange with blood vessels occurs across the walls of?
Gas exchange occurs across the walls of the alveoli
In which of the following animals are the blood and the interstitial fluid considered to be the same body fluid? -fishes -sparrows -grasshoppers -dogs -jellyfish and cnidarians
Grasshoppers- within an open circulatory system, such as that operating in insects, the body fluid, called hemolymph, bathes the organs directly as it is pumped between open spaces in the body.
Compared with the interstitial fluid that bathes active muscle cells, blood reaching these cells in arteries has a
Higher P(O2).
Which statement regarding the mammalian heart is correct? -Blood arrives at the heart via the ventricles. -In the adult heart, blood in the right chambers of the heart cannot enter the left chambers without passing through the lungs. -When the right atrium contracts, it forces blood into the left atrium. -Oxygen-loaded blood moves only through the right side of the heart. -Blood is pumped from the heart via the atria.
In the adult heart, blood in the right chambers of the heart cannot enter the left chambers without passing through the lungs- the right heart's contraction moves the blood to the lungs for gas exchange before the blood is delivered to the left atrium.
The amount of oxygen bound to hemoglobin _____.
Increases in the presence of high concentrations of oxygen- high concentrations of oxygen increase the amount of oxygen bound to hemoglobin.
Which component of a homeostatic system compares sensory information to a target value? -Sensor. -Set point. -Effector. -Integrator.
Integrator- sends instructions to an effector based on sensory information.
All types of muscle tissue have _____. -interactions between actin and myosin -cells that lengthen when appropriately stimulated -striated banding patterns seen under the microscope -a response that can be consciously controlled
Interactions between actin and myosin
Which of these describes loose connective tissue? -It is a loose weave of fibers that functions as a packing material. -It is composed of many fibers that connect bone to bone and muscle to bone. -It is a rigid material that provides structural support. -It transports nutrients and gases from one part of the body to another. -It plays a role in padding, insulation, and energy storage.
It is a loose weave of fibers that functions as a packing material- a packing material that serves, for example, to hold organs in place
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
Blood is best classified as connective tissue because _____. -it contains more than one type of cell -its cells are separated from each other by an extracellular matrix -it is found within all the organs of the body -its cells can move from place to place
Its cells are separated from each other by an extracellular matrix
Voice sounds are produced by the _____.
Larnx- houses the vocal cords.
From the pulmonary veins, blood flows to the _____.
Left atrium- blood enters the left atrium via the pulmonary veins.
Compared with a smaller cell, a larger cell of the same shape has _____. -a smaller average distance between its mitochondria and the external source of oxygen -less surface area -a smaller cytoplasm-to-nucleus ratio -less surface area per unit of volume
Less surface area per unit of volume
Which of the following is a correct match of cell type with structure? -nerve cell ... closely joined -skin cell ... has a large volume -intestinal cell ... closely joined -muscle cell ... has proteins that slide back and forth -skin cell ... has long extensions
Muscle cell... has proteins that slide back and forth- these proteins help muscles to contract.
The primary functions of the _____ are to warm, filter, and humidify air.
Nasal cavity
Capillary beds are the site of?
Nutrient and oxygen delivery to tissues.
Once labor begins in childbirth, contractions increase in intensity and frequency, causing more contractions to occur until delivery. The increasing labor contractions of childbirth are an example of which type of regulation? -enzymatic catalysis -negative feedback -feedback inhibition -positive feedback
Positive feedback
From the capillaries of the abdominal organs and hind limbs, blood flows to the _____.
Posterior vena cava- blood enters the posterior vena cava from the capillaries of the abdominal organs and hind limbs.
Which statement about human blood vessels is correct? -Pulmonary veins carry oxygen-rich blood to the heart. -Veins transport blood from the heart to the capillaries. -Arteries carry blood toward the atria of the heart. -Arteries carry oxygenated blood; veins carry oxygen-poor blood. -The pulmonary artery carries oxygen-rich blood from the lungs.
Pulmonary veins carry oxygen-rich blood to the heart- following gas exchange in the lungs, the blood moves into the pulmonary veins for its return to the left atrium and then on into the highly muscular left ventricle.
Blood returns to the heart via the _____.
Pulmonary veins- carry oxygenated blood from the lungs to the left atrium.
Which term describes a mechanism by which the internal conditions of an organism are kept at set values without regard to the external conditions? -Conformational homeostasis. -Regulatory homeostasis. -Thermoregulation. -Negative feedback.
Regulatory homeostasis- regulatory homeostasis involves adjusting the internal conditions of an organism to set values without regard to the external conditions.
Connective tissues typically have _____. -relatively few cells and a large amount of extracellular matrix -the ability to transmit electrochemical impulses -the ability to shorten upon stimulation -little space between the membranes of adjacent cells
Relatively few cells and a large amount of extracellular matrix
From the anterior vena cava, blood flows to the _____.
Right atrium- blood enters the right atrium from the anterior and posterior venae cavae.
You have a cube of modeling clay in your hands. Which of the following changes to the shape of this cube of clay will decrease its surface area relative to its volume? -Stretch the cube into a long, shoebox shape. -Round the clay up into a sphere. -Flatten the cube into a pancake shape. -Pinch the edges of the cube into small folds.
Round the clay up into a sphere
Which of these tissues, found in the lungs, permits gas exchange by diffusion? -stratified squamous epithelium -simple cuboidal cells -stratified cuboidal epithelium -simple squamous epithelium -simple columnar epithelium
SImple squamous epithelium- this is a thin single layer of cells that allows for diffusion
Which component of a homeostatic system perceives changes in some parameter of the environment? -Integrator. -Sensor. -Effector. -Set point.
Sensor- perceives changes in some parameter of the environment
Which of the following actions acts to warm a homeothermic body? -Shivering. -Dilating blood vessels. -Sweating. -Panting.
Shivering- generates metabolic heat and warms the body.
What type of epithelial tissue, found in the intestines, absorbs nutrients? -stratified cuboidal epithelium -simple cuboidal cells -simple columnar epithelium -stratified columnar epithelium -stratified squamous epithelium
Simple columnar epithelium- specialized for absorption and secretion.
What type of epithelial tissue lines kidney tubules? -stratified squamous epithelium -stratified cuboidal epithelium -simple squamous epithelium -simple cuboidal cells -stratified transitional epithelium
Simple cuboidal cells- allow for both secretion and absorption.
Of the following choices, the epithelium with the shortest diffusion distance is _____. -pseudostratified ciliated columnar epithelium -simple squamous epithelium -simple columnar epithelium -stratified squamous epithelium
Simple squamous epithelium
_____ muscle is attached to bones. -Smooth -Involuntary -Cardiac -Branched -Skeletal
Skeletal- skeletal muscle is attached to bones.
Food moves along the digestive tract as the result of contractions by _____. -skeletal muscle -striated muscle -cardiac muscle -smooth muscle
Smooth muscle
What type of muscle is responsible for contractions of the digestive tract and arteries? -smooth muscle -skeletal muscle -striated muscle -voluntary muscle -cardiac muscle
Smooth muscle- responsible for the involuntary contractions of the digestive tract, arteries, and bladder.
What type of epithelium would you expect to find covering a surface subject to physical forces? -simple epithelium -squamous epithelium -stratified epithelium -simple cuboidal cells -columnar epithelium
Stratified epithelium- consists of multiple layers; this thickness provides a protective barrier.
Cardiac muscle cells are both _____. -smooth and under voluntary control -striated and under voluntary control -striated and interconnected by intercalated disks -smooth and under involuntary control
Striated and interconnected by intercalated disks
If an organism was discovered that had no epithelial tissues, it would require adaptations to maintain homeostasis in which of the following areas? The organism would require adaptations _____. -that would prevent water loss from the body in a terrestrial environment -in its skeleton for structure -in its muscular system for movement -in its nervous system for sensing external stimuli
That would prevent water loss from the body in a terrestrial environment
Which event occurs first during diastole?
The atria and ventricles are relaxed, and blood flows into the atria- diastole is the relaxation phase of the cardiac cycle during which the chambers of the heart are relaxed and blood can enter them passively.
An example of a properly functioning homeostatic control system is seen when _____. -a blood cell shrinks when placed in a solution of salt and water -the core body temperature of a runner rises gradually from 37°C to 45°C -the blood pressure increases in response to an increase in blood volume -the kidneys excrete salt into the urine when dietary salt levels rise
The kidneys excrete salt into the urine when dietary salt levels rise
Why do the circulatory systems of land vertebrates have separate circuits to the lungs and to 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- the changes in blood pressure as blood moves through the lungs of land-dwelling vertebrates make it necessary to have separate circuits to the lungs and the rest of the body.
One feature that amphibians and humans have in common is?
The number of circuits for circulation.
If a molecule of CO2 released into the blood in your left toe is exhaled from your nose, it must pass through all of the following except -an alveolus. -the trachea. -the right atrium. -the right ventricle. -the pulmonary vein.
The pulmonary vein
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 systolic blood pressure is the peak blood pressure, resulting from contraction of the ventricles.
Nervous tissue functions _____. -as a physical barrier to the invasion of pathogens -to physically move the body -to sense stimuli -to physically support the body -in the absorption of nutrients
To sense stimuli- this is one of the functions of nervous tissue.
An advantage of gas exchange in fresh water, compared with gas exchange in air, is that _____.
Water loss through evaporation across the respiratory surface can be minimized- respiratory surfaces are always moist, and exposure to air results in water loss via evaporation.
Which of the following is an example of negative feedback? -During birthing contractions, oxytocin (a hormone) is released and acts to stimulate further contractions. -When the level of glucose in the blood increases, the pancreas produces and releases the hormone insulin. Insulin acts to decrease blood glucose. As blood glucose decreases, the rate of production and release of insulin decreases as blood glucose decreases. -When a baby is nursing, suckling leads to the production of more milk and a subsequent increase in the secretion of prolactin (a hormone that stimulates lactation). -After a blood vessel is damaged, signals are released by the damaged tissues that activate platelets in the blood. These activated platelets release chemicals that activate more platelets.
When the level of glucose in the blood increases, the pancreas produces and releases the hormone insulin. Insulin acts to decrease blood glucose. As blood glucose decreases, the rate of production and release of insulin decreases as blood glucose decreases.
