1.
The neurohormones antidiuretic hormone (vasopressin) and oxytocin are produced by the
Correct Answer
B. Hypothalamus u s and released by the posterior pituitary
Explanation
The correct answer is "hypothalamus u s and released by the posterior pituitary." The hypothalamus produces antidiuretic hormone (vasopressin) and oxytocin, which are then transported to the posterior pituitary for storage and release into the bloodstream when needed. Therefore, the hormones are produced by the hypothalamus and released by the posterior pituitary.
2.
Columnar cells are a type of epithelial tissue often found in the ________ and their function is_______
Correct Answer
D. Intestines, absorption
Explanation
Columnar cells are a type of epithelial tissue often found in the intestines. Their function is absorption. These cells have a tall and narrow shape, which allows for increased surface area for absorption of nutrients and other substances from the digested food in the intestines. The columnar shape also helps in the secretion of mucus and enzymes that aid in the digestive process.
3.
Which of the following is not one of the distinct chemical groups to which hormones belong?
Correct Answer
D. Carbonhydrates
Explanation
Carbohydrates are not one of the distinct chemical groups to which hormones belong. Hormones are typically classified into four main groups: steroids, proteins, peptides, and amines. Carbohydrates do not possess the necessary chemical structure or properties to function as hormones. They primarily serve as a source of energy in the body and play a role in cellular processes, but they are not involved in hormonal signaling.
4.
The specialized structures of complex animals have evolved because
Correct Answer
D. They permit adjustments to a wide range of environmental changes.
Explanation
The specialized structures of complex animals have evolved because they permit adjustments to a wide range of environmental changes. This means that these structures allow animals to adapt and survive in different environments, regardless of their location. By having specialized structures, animals can effectively respond to various challenges and changes in their surroundings, enhancing their chances of survival and reproductive success.
5.
As body size increases in animals,
Correct Answer
A. There is a decrease in the surface-to-volume ratio.
Explanation
As body size increases in animals, there is a decrease in the surface-to-volume ratio. This is because the volume of an animal increases at a faster rate than its surface area as it grows larger. The surface-to-volume ratio is important for various physiological processes such as exchange of gases and nutrients with the environment. A smaller surface-to-volume ratio means that there is less surface area available for these exchanges, which can lead to limitations in the animal's ability to obtain necessary resources.
6.
Receptors for many steroid hormones are located:
Correct Answer
A. Within the nucleus
Explanation
Steroid hormones are lipophilic molecules that can easily cross the cell membrane. Once inside the cell, they bind to specific receptor proteins located within the nucleus. This hormone-receptor complex then acts as a transcription factor, directly affecting gene expression and leading to various cellular responses. Therefore, the correct answer is "within the nucleus."
7.
Which of the following is an effect of increased levels of antidiuretic hormone in the blood?
Correct Answer
C. Water conservation by the kidney
Explanation
Increased levels of antidiuretic hormone (ADH) in the blood result in water conservation by the kidney. ADH, also known as vasopressin, is released by the posterior pituitary gland in response to low blood volume or increased blood osmolality. It acts on the kidneys to increase water reabsorption, reducing the amount of water excreted in urine. This helps to maintain water balance in the body and prevent dehydration. The other options listed are not effects of increased levels of ADH.
8.
Interstitial fluid is
Correct Answer
D. The route for the exchange of materials between blood and body cells
Explanation
Interstitial fluid is the fluid that surrounds and bathes the cells in the body. It is derived from blood plasma and contains nutrients, oxygen, hormones, and waste products. It serves as a medium for the exchange of materials between the blood and body cells, allowing for the delivery of nutrients and removal of waste products. This exchange is essential for maintaining cellular function and homeostasis.
9.
In addition to producing thyroxine, the mammalian thyroid gland produces
Correct Answer
D. Calcitonin
Explanation
The mammalian thyroid gland produces calcitonin in addition to thyroxine. Calcitonin is a hormone that helps regulate calcium levels in the body. It works by inhibiting the activity of osteoclasts, which are cells that break down bone tissue and release calcium into the bloodstream. By inhibiting osteoclast activity, calcitonin helps to decrease blood calcium levels. This hormone is important in maintaining calcium homeostasis and preventing excessive calcium loss from the bones.
10.
.Which of the following is an example of a positive feedback control system?
Correct Answer
A. During birth, the baby’s head presses against the cervix and stretches it; stretch of the cervix stimulates the release of oxytocin; oxytocin causes contractions of muscles in the uterus; this pushes the baby against the cervix harder, increasing the stretch of the cervix.
11.
Hormones are secreted by
Correct Answer
E. All of the above
Explanation
Hormones are chemical messengers that are secreted by various glands and cells in the body. The endocrine glands, such as the thyroid gland, are specialized organs that release hormones directly into the bloodstream. However, individual cells, such as those lining portions of the digestive tract, can also secrete hormones. Additionally, exocrine glands, like the pancreas, can release hormones along with other substances through ducts. Therefore, the correct answer is "All of the above" as hormones can be secreted by endocrine glands, individual cells, and exocrine glands.
12.
Tissues are composed of cells, and tissues functioning together make up
Correct Answer
A. Organs
Explanation
Tissues are groups of cells that work together to perform a specific function. Organs, on the other hand, are made up of different types of tissues that work together to perform a specific function for the body. Therefore, organs are the correct answer because they are composed of tissues functioning together. Membranes are thin layers of tissue that cover surfaces or line body cavities, but they do not make up organs. Organ systems are groups of organs that work together to perform a specific function, and organelles are small structures within cells that perform specific functions. Organisms refer to living beings as a whole, which is beyond the scope of the question.
13.
The hormones antidiuretic hormone (vasopressin) and oxytocin are produced by the
Correct Answer
B. Hypothalamus and released by the posterior pituitary.
Explanation
The hormones antidiuretic hormone (vasopressin) and oxytocin are produced by the hypothalamus and released by the posterior pituitary. The hypothalamus is responsible for producing these hormones and then sending them to the posterior pituitary for release into the bloodstream. This is a well-known and established fact in endocrinology.
14.
Of the following choices, the epithelium with the shortest diffusion distance is
Correct Answer
A. Simp1e squamous epithelium.
Explanation
The epithelium with the shortest diffusion distance is simple squamous epithelium. This type of epithelium consists of a single layer of flat cells, which allows for efficient diffusion of substances across the cell membrane. The thinness of the cells reduces the distance that molecules need to travel, facilitating rapid diffusion. In contrast, other types of epithelium such as simple cuboidal or columnar epithelium have thicker cells and therefore longer diffusion distances. Stratified squamous epithelium is composed of multiple layers of cells, further increasing the diffusion distance. Pseudostratified ciliated columnar epithelium is also thicker due to the presence of cilia, which adds to the diffusion distance.
15.
The type of muscle tissue surrounding internal organs, other than the heart, is
Correct Answer
E. Smooth muscle
Explanation
Smooth muscle is the correct answer because it is the type of muscle tissue that surrounds internal organs, other than the heart. Smooth muscle is involuntary and lacks striations, unlike skeletal muscle and cardiac muscle. Intercalated cells are found in cardiac muscle and are responsible for coordinating contractions. Therefore, smooth muscle is the most appropriate choice for the given question.
16.
The nourishment, insulation, and support for neurons is the result of activity by the
Correct Answer
E. Glial cells
Explanation
Glial cells provide nourishment, insulation, and support for neurons. They help in maintaining the overall health and functioning of neurons by supplying them with essential nutrients, removing waste products, and providing structural support. Glial cells also play a role in insulating neurons by forming a protective covering called myelin around their axons, which helps in the efficient transmission of electrical signals. Additionally, glial cells contribute to the regulation of the chemical environment around neurons and provide support during injury or disease.
17.
For hormones that homeostatically reu1ate cellular functions
Correct Answer
A. Negative feedback typically regulates hormone secretion
Explanation
Negative feedback is a mechanism in which the output of a system inhibits or dampens the original stimulus, thus maintaining stability and balance. In the context of hormone regulation, negative feedback is the most common mechanism used to maintain homeostasis. When hormone levels rise above a certain threshold, negative feedback signals the endocrine gland to decrease hormone secretion. Conversely, when hormone levels fall below a certain threshold, negative feedback signals the endocrine gland to increase hormone secretion. This feedback loop helps to keep the circulating level of hormones within a narrow range, ensuring proper cellular functions.
18.
Muscles are joined to bones by
Correct Answer
B. Tendons
Explanation
Tendons are the correct answer because they are the fibrous connective tissues that attach muscles to bones. They are strong and flexible, allowing for movement and transmitting the force generated by the muscles to the bones, enabling movement and stability. Ligaments, on the other hand, join bones to other bones, while loose connective tissue is a type of connective tissue that provides support and flexibility. Haversian systems and spindle fibers are unrelated to the attachment of muscles to bones.
19.
The integrator for human temperature regulation is located in the
Correct Answer
C. Hypothalamus
Explanation
The hypothalamus is responsible for regulating body temperature in humans. It acts as the integrator by receiving information from temperature sensors throughout the body and then sending signals to other parts of the body to initiate appropriate responses. These responses can include sweating or shivering to adjust body temperature as needed. The hypothalamus is located in the brain and plays a crucial role in maintaining homeostasis.
20.
Feedback regulation is an important feature of endocrine communication. Which type of feedback predominates?
Correct Answer
A. Negative
Explanation
Negative feedback predominates in endocrine communication. This means that when the levels of a hormone in the body reach a certain threshold, the endocrine system will release a signal to decrease the production or release of that hormone. This helps to maintain homeostasis and prevent excessive hormone levels. Positive feedback, on the other hand, amplifies the production or release of a hormone, while the other options (ergometric, neutral, homeometric) are not relevant to the concept of feedback regulation in endocrine communication.
21.
Which of the following is not one of the distinct chemical groups to which hormones belong?
Correct Answer
C. Carbohydrates
Explanation
Carbohydrates are not one of the distinct chemical groups to which hormones belong. Hormones are typically classified into three main groups: steroids, proteins, and amines. Steroids are derived from cholesterol and include hormones such as estrogen and testosterone. Proteins are made up of amino acids and include hormones like insulin and growth hormone. Amines are derived from amino acids and include hormones like epinephrine and norepinephrine. Carbohydrates, on the other hand, are not involved in hormone production or function.
22.
The time of action for peptide hormones is typically:
Correct Answer
D. More rapid than steroid hormones
Explanation
Peptide hormones typically have a more rapid time of action compared to steroid hormones. This is because peptide hormones bind to specific receptors on the cell surface, triggering a cascade of intracellular signaling events that result in a rapid response. In contrast, steroid hormones enter the cell and bind to intracellular receptors, which then directly affect gene expression, a process that takes longer. Therefore, the time of action for peptide hormones is faster than that of steroid hormones.
23.
Insulin secretion from the pancreas increases in response to:
Correct Answer
B. Increased blood glucose concentration
Explanation
Insulin is a hormone released by the pancreas in response to high blood glucose levels. When blood glucose concentration increases, the pancreas detects this and secretes insulin to help regulate it. Insulin allows cells to take in glucose from the bloodstream, thus lowering blood glucose levels. Therefore, increased blood glucose concentration triggers insulin secretion from the pancreas.
24.
Most types of communication between cells use
Correct Answer
C. The release of chemical signals by the cell sending the message.
Explanation
Cells communicate with each other through the release of chemical signals. These chemical signals, also known as signaling molecules or ligands, are released by the cell sending the message and can travel through the extracellular fluid to reach the target cell. Once the signaling molecule reaches the target cell, it binds to specific receptors on the cell surface, initiating a response within the target cell. This type of communication allows cells to coordinate their activities, regulate processes, and respond to changes in their environment.
25.
Humans are called homeotherms because we maintain constant
Correct Answer
D. Rates of heat production in any environment
Explanation
Homeotherms are organisms that are able to maintain a relatively constant internal body temperature regardless of the external environment. This is achieved by regulating the rates of heat production in their bodies. By adjusting metabolic processes and increasing heat production, homeotherms can stay warm in cold environments and cool down in hot environments. This ability allows them to function optimally and survive in a wide range of environmental conditions.
26.
Hormones are involved in regulating processes related to:
Correct Answer
E. All of the above
Explanation
Hormones play a crucial role in regulating various processes in the body. They are involved in the production, use, and storage of metabolic energy, ensuring that the body has the necessary energy for its functions. Hormones also regulate reproductive functions, including the menstrual cycle in females and sperm production in males. They are essential for growth and development, controlling the growth of tissues and organs during childhood and adolescence. Additionally, hormones help maintain salt and water balance in the body, ensuring proper hydration and electrolyte levels. Therefore, all of the options mentioned are correct as hormones are involved in regulating all of these processes.
27.
Conduction removes heat from the body whenever the body is:
Correct Answer
D. ìn contact with an object that is cooler than skin temperature
Explanation
Conduction is the transfer of heat between two objects that are in direct contact with each other. In this case, if the body is in contact with an object that is cooler than skin temperature, heat will be transferred from the body to the cooler object through conduction. This will result in the removal of heat from the body.
28.
Which of the following statements about hormones, hormone-producing cells, and target cells is false?
Correct Answer
D. All hormones travel in the blood to target cells.
Explanation
The statement "All hormones travel in the blood to target cells" is false. While many hormones do travel in the blood to reach their target cells, there are also hormones that can travel through other bodily fluids or can act locally without entering the bloodstream. For example, some hormones can act on nearby cells without being transported in the blood. Additionally, some hormones can be transported through other bodily fluids such as lymph.
29.
In a typical nerve cell, the nucleus is found in the
Correct Answer
A. Cell body
Explanation
The nucleus is found in the cell body of a typical nerve cell. The cell body, also known as the soma, is the main part of the neuron that contains the nucleus along with other organelles necessary for cellular function. It is responsible for maintaining the overall health and functioning of the neuron. The axonal region is where the axon originates from the cell body, while the dendritic region is where the dendrites extend from the cell body. The synaptic terminals are located at the end of the axon and are involved in transmitting signals to other neurons at the synapse.
30.
Steroid hormones
Correct Answer
A. Bind to receptor proteins in the cytoplasm or nucleus.
Explanation
Steroid hormones are able to bind to receptor proteins in the cytoplasm or nucleus. This is because steroid hormones are lipid-soluble and can easily pass through the cell membrane. Once inside the cell, they bind to specific receptor proteins located in the cytoplasm or nucleus. This binding activates the receptor, leading to changes in gene expression and protein synthesis. Therefore, the correct answer is that steroid hormones bind to receptor proteins in the cytoplasm or nucleus.
31.
All skeletal muscle fibers are both
Correct Answer
C. Striated and under voluntary control
Explanation
Skeletal muscle fibers are striated because they have a striped appearance due to the arrangement of contractile proteins. They are under voluntary control, meaning that they can be consciously controlled by the individual. This allows for precise movements and coordination.
32.
Most cellular functions are limited to a temperature ranging (in °C) from to
Correct Answer
C. 0; 40
Explanation
The correct answer is 0; 40. This is because most cellular functions are optimized to occur within a specific temperature range. Temperatures below 0°C can cause the formation of ice crystals that can damage cellular structures, while temperatures above 40°C can denature proteins and disrupt cellular processes. Therefore, the temperature range of 0; 40°C is considered optimal for cellular functions.
33.
The hypothalamus
Correct Answer
E. Inc1udes neurosecretory cells that terminate in the posterior pituitary.
Explanation
The correct answer is "includes neurosecretory cells that terminate in the posterior pituitary." The hypothalamus is a region of the brain that plays a crucial role in regulating various bodily functions, including hormone production and release. It contains neurosecretory cells that produce hormones, such as oxytocin and vasopressin, which are then transported and released in the posterior pituitary gland. These hormones, in turn, regulate processes such as childbirth, lactation, and water balance. Therefore, the statement that the hypothalamus includes neurosecretory cells that terminate in the posterior pituitary is an accurate description of its function.
34.
Bone is a type of tissue.
Correct Answer
A. Connective
Explanation
Connective tissue is the correct answer because bone is classified as a connective tissue. Connective tissues are characterized by having cells dispersed in an extracellular matrix, which provides structural support and connects different tissues and organs in the body. Bone tissue contains specialized cells called osteoblasts and osteoclasts that are responsible for bone formation and remodeling. The extracellular matrix of bone is composed of collagen fibers and mineralized deposits, giving bone its strength and rigidity. Therefore, bone fits the characteristics of connective tissue, making connective the correct answer.
35.
Endothermy
Correct Answer
B. Is a characteristic of animals that have a fairly constant body temperature
Explanation
Endothermy is a characteristic of animals that have a fairly constant body temperature. This means that these animals are able to regulate their body temperature internally, regardless of the external temperature. They can generate heat through metabolic processes and maintain a stable body temperature, which allows them to thrive in various environments. This is different from ectothermic animals, which rely on external sources of heat to regulate their body temperature. Endothermy is not limited to any specific group of animals, but is found in a variety of species including mammals, birds, and some reptiles.
36.
The reason that the steroid hormone aldosterone affects only a small number of cells in the body is that
Correct Answer
B. Only its target cells contain aldosterone receptors
Explanation
The reason that the steroid hormone aldosterone affects only a small number of cells in the body is that only its target cells contain aldosterone receptors. These receptors are specific to aldosterone and are present only in the cells that are intended to respond to its effects. Therefore, only the cells with aldosterone receptors are able to bind and respond to aldosterone, while the other cells in the body do not have the necessary receptors to be affected by this hormone.
37.
Under which of the following conditions would a mammal tend to increase thyroxine levels?
Correct Answer
E. When exposed to cold
Explanation
When exposed to cold, a mammal tends to increase thyroxine levels. Thyroxine is a hormone produced by the thyroid gland, and it plays a crucial role in regulating the body's metabolism and maintaining body temperature. When the body is exposed to cold temperatures, it needs to generate more heat to keep warm. Increasing thyroxine levels helps to increase the metabolic rate, which in turn generates more heat and helps the mammal adapt to the cold environment.
38.
A cell with membrane-bound proteins that selectively bind a specific hormone is called that hormones
Correct Answer
D. Target cell.
Explanation
A cell with membrane-bound proteins that selectively bind a specific hormone is called a target cell because it is the specific cell that the hormone acts upon. The hormone binds to the membrane-bound proteins on the target cell, triggering a response or signaling pathway within the cell. This interaction between the hormone and its target cell is crucial for the hormone to exert its effects and regulate various physiological processes in the body.
39.
Oxytocin and antidiuretic hormone are synthesized in the
Correct Answer
A. Hypothalamus
Explanation
Oxytocin and antidiuretic hormone are synthesized in the hypothalamus. The hypothalamus is a small region of the brain that plays a crucial role in regulating various bodily functions, including the production and release of hormones. Oxytocin is involved in a variety of physiological processes, such as childbirth and breastfeeding, while antidiuretic hormone helps to regulate water balance in the body. Both of these hormones are produced in the hypothalamus and then transported to the posterior pituitary gland for storage and release into the bloodstream when needed.
40.
In regulatory systems, the phenomenon of negative feedback
Correct Answer
B. Stimulates a return to set point
Explanation
Negative feedback is a regulatory mechanism that helps maintain stability and balance in a system. It works by detecting any deviation from the set point and initiating corrective actions to bring the system back to its desired state. Therefore, the correct answer, "stimulates a return to set point," accurately describes the role of negative feedback in regulatory systems.
41.
Iodine is added to table salt to help prevent deficiencies of an essential mineral needed for the proper function of the
Correct Answer
C. Thyroid glands.
Explanation
Iodine is added to table salt to help prevent deficiencies of an essential mineral needed for the proper function of the thyroid glands. The thyroid glands are responsible for producing hormones that regulate metabolism, growth, and development in the body. Iodine is a crucial component in the production of these hormones, and a deficiency in iodine can lead to thyroid disorders such as goiter or hypothyroidism. Therefore, adding iodine to table salt helps ensure that individuals receive an adequate amount of this essential mineral and maintain proper thyroid function.
42.
The endocrine glands include the
Correct Answer
A. Parathyroid glands
Explanation
The parathyroid glands are a part of the endocrine system. They are small glands located near the thyroid gland in the neck. These glands produce and release parathyroid hormone (PTH), which helps regulate the levels of calcium and phosphorus in the body. PTH acts on the bones, kidneys, and intestines to increase calcium levels in the blood when they are too low. Therefore, the parathyroid glands are responsible for maintaining proper calcium balance in the body.
43.
Which of the following statements about muscle tissue is false?
Correct Answer
C. It is a form of connective tissue.
Explanation
Muscle tissue is not a form of connective tissue. Connective tissue is a type of tissue that supports, connects, or separates different types of tissues and organs in the body. Muscle tissue, on the other hand, is responsible for movement and contraction. It is made up of specialized cells called muscle fibers that have the ability to contract and generate force. Therefore, the statement that muscle tissue is a form of connective tissue is false.
44.
Humans can lose, but cannot gain, heat through the process of
Correct Answer
D. Evaporation.
Explanation
Evaporation is the process by which a liquid turns into a gas. In terms of heat transfer, evaporation allows humans to lose heat from their bodies. When sweat evaporates from the skin, it takes away heat energy from the body, cooling it down. On the other hand, conduction, convection, and radiation are all processes that involve the transfer of heat to an object or from one object to another, but they do not specifically involve the loss of heat from the human body. Metabolism is the chemical processes occurring within a living organism to maintain life, and it does not directly involve heat transfer.
45.
Which of the following has both endocrine and exocrine activity?
Correct Answer
D. The pancreas
Explanation
The pancreas has both endocrine and exocrine activity. It functions as an endocrine gland by producing and releasing hormones such as insulin and glucagon into the bloodstream to regulate blood sugar levels. Additionally, it acts as an exocrine gland by producing enzymes that are released into the small intestine to aid in the digestion and absorption of nutrients.
46.
When blood glucose levels increase, which of the following increases?
Correct Answer
B. Insulin
Explanation
Insulin increases when blood glucose levels increase. Insulin is a hormone produced by the pancreas that helps regulate blood sugar levels by allowing cells to take in glucose from the bloodstream. When blood glucose levels rise, the pancreas releases insulin to signal cells to absorb and use the excess glucose for energy or storage. This helps lower blood sugar levels back to normal.
47.
Analysis of a blood sample from a fasting individual who had not eaten for 24 hours would be expected to reveal high levels of
Correct Answer
B. Glucagon
Explanation
When an individual is fasting and has not eaten for 24 hours, the body needs to maintain stable blood glucose levels. Glucagon is a hormone released by the pancreas in response to low blood glucose levels. It stimulates the liver to break down glycogen into glucose and release it into the bloodstream, increasing blood glucose levels. Therefore, it is expected that the analysis of a blood sample from a fasting individual would reveal high levels of glucagon.
48.
Cardiac muscle cells are both
Correct Answer
A. Striated and interconnected by intercalated disks
Explanation
Cardiac muscle cells are striated, meaning they have a striped appearance due to the arrangement of contractile proteins. Additionally, these cells are interconnected by intercalated disks, which allow for synchronized contraction of the heart. This interconnection ensures that the cardiac muscle cells work together as a unit, enabling efficient pumping of blood. Therefore, the correct answer is "striated and interconnected by intercalated disks."
49.
Melatonin is secreted by
Correct Answer
B. The pineal gland during the night
Explanation
Melatonin is a hormone that regulates the sleep-wake cycle. It is primarily secreted by the pineal gland, a small gland located in the brain, during the night. The secretion of melatonin is influenced by the amount of light received by the retina. When it gets dark, the pineal gland releases melatonin, which helps to induce sleep and promote a restful night's sleep. During the day, the secretion of melatonin is inhibited by the presence of light. Therefore, the correct answer is that melatonin is secreted by the pineal gland during the night.
50.
An example of effectors’ roles in homeostatic responses is observable when
Correct Answer
A. An increase in body temperature results from involuntary shivering
Explanation
When the body temperature increases, involuntary shivering is a response that helps to regulate and lower the body temperature. Shivering is an effect of the body's homeostatic response to maintain a stable internal temperature. It occurs when the body tries to generate heat by contracting and relaxing muscles rapidly. This response increases the metabolic rate and generates heat, which helps to counteract the increase in body temperature. Therefore, the given answer correctly identifies the role of effectors (involuntary shivering) in a homeostatic response to an increase in body temperature.