1.
The physiological concept that refers to the maintenance of a constant environment is
Correct Answer
C. Homeostasis
Explanation
Homeostasis is the physiological concept that refers to the maintenance of a constant environment within the body. It involves the regulation of various parameters such as body temperature, blood pressure, and pH levels to ensure optimal functioning of the body's cells and organs. Through feedback mechanisms, the body is able to detect and respond to changes in these parameters, restoring them to their normal range. This concept is essential for the overall health and stability of an organism.
2.
The organelles that contain enzymes capable of digesting and destroying cellular debris
Correct Answer
D. Lysosomes
Explanation
Lysosomes are organelles that contain enzymes capable of digesting and destroying cellular debris. They are responsible for breaking down waste materials, old cell parts, and foreign substances that enter the cell. Lysosomes help maintain the overall health and cleanliness of the cell by removing unnecessary or harmful materials. The other organelles listed in the options, such as the endoplasmic reticulum, Golgi apparatus, mitochondria, and ribosomes, have different functions and are not primarily involved in the digestion and destruction of cellular debris.
3.
Transport of water across a cell membrane
Correct Answer
D. Diffusion
Explanation
Diffusion is the process by which molecules move from an area of higher concentration to an area of lower concentration, without the need for energy input. In the context of water transport across a cell membrane, diffusion refers to the movement of water molecules from an area of higher water concentration (hypotonic) to an area of lower water concentration (hypertonic) through the lipid bilayer of the membrane. This movement occurs until equilibrium is reached, where the concentration of water is equal on both sides of the membrane. Therefore, diffusion is the correct answer for the transport of water across a cell membrane.
4.
The direction and rate of diffusion of an ion is influenced by the
Correct Answer
D. All of the above
Explanation
The direction and rate of diffusion of an ion is influenced by the concentration gradient, which refers to the difference in concentration between two areas. It is also influenced by the hydrostatic pressure gradient, which is the difference in pressure between two areas. Additionally, the electrical gradient, which is the difference in electrical charge between two areas, also affects the direction and rate of ion diffusion. Therefore, all of these factors play a role in determining the direction and rate of ion diffusion.
5.
Active transport differs from facilitated diffusion in that active transport
Correct Answer
E. All of the above
Explanation
Active transport differs from facilitated diffusion in multiple ways. Firstly, active transport moves a substance against its concentration gradient, meaning it moves from an area of low concentration to an area of high concentration. On the other hand, facilitated diffusion moves substances along their concentration gradient, from an area of high concentration to an area of low concentration. Secondly, active transport requires a carrier protein to transport the substance across the cell membrane, while facilitated diffusion does not require a carrier protein. Lastly, active transport requires energy in the form of magnesium adenosine triphosphate (Mg ATP), whereas facilitated diffusion does not require energy. The movement of sodium and potassium across cell membranes is an example of active transport. Therefore, all of the above statements are correct explanations of the differences between active transport and facilitated diffusion.
6.
All of the following are derived from endoderm except
Correct Answer
C. Epithelium in the mouth
Explanation
The correct answer is "epithelium in the mouth". The mouth is derived from ectoderm, not endoderm. The respiratory system, gastrointestinal system, and pharynx are all derived from endoderm.
7.
Which of the following is derived from mesoderm?
Correct Answer
E. Connective tissue
Explanation
Connective tissue is derived from mesoderm. During embryonic development, the mesoderm gives rise to various tissues and organs, including connective tissue. Connective tissue is a type of tissue that provides support, structure, and connects different parts of the body. It includes various types of cells, fibers, and ground substance. Examples of connective tissue include bone, cartilage, tendons, ligaments, and blood.
8.
The developmental period in which teeth and the palate are most susceptible to teratogenic agents is the
Correct Answer
D. Eighth through the tenth week
Explanation
the most rapid developmental time
9.
Gingiva and buccal mucosa
Correct Answer
B. Stratified squamous epithelium
Explanation
The gingiva and buccal mucosa are both areas in the oral cavity that are exposed to mechanical stress and abrasion. Stratified squamous epithelium is the ideal type of epithelium for these areas because it provides protection against wear and tear. This type of epithelium consists of multiple layers of cells, with the outermost layer being flattened and squamous in shape. The stratified nature of the epithelium allows for increased durability and resistance to damage, making it well-suited for the gingiva and buccal mucosa.
10.
What type of connective tissue is present in scar tissue?
Correct Answer
B. Dense fibrous
Explanation
Scar tissue is formed during the process of wound healing, where there is an excessive production of collagen fibers. Dense fibrous connective tissue is the correct answer because it is characterized by a high density of collagen fibers, which provide strength and support to the scar tissue. This type of connective tissue is commonly found in tendons, ligaments, and the dermis of the skin, making it the most suitable option for scar tissue.
11.
What kind of cell types line the vascular channels of the body?
Correct Answer
B. Endothelium
Explanation
The correct answer is endothelium. Endothelium is a type of epithelial tissue that lines the inner surface of blood vessels and lymphatic vessels. It is a single layer of cells that helps in the transport of substances, such as oxygen and nutrients, across the vessel walls. Endothelial cells also play a role in regulating blood flow and immune responses. Stratified squamous epithelium, mesothelium, transitional epithelium, and pseudostratified columnar epithelium are not typically found lining vascular channels in the body.
12.
Pleura is a type of
Correct Answer
A. Serous membrane
Explanation
The pleura is a serous membrane that lines the lungs and the inner surface of the chest cavity. Serous membranes are thin, double-layered membranes that secrete a lubricating fluid, allowing organs to move smoothly against each other. The pleura specifically consists of two layers - the visceral pleura, which covers the lungs, and the parietal pleura, which lines the chest wall. Together, these layers help protect and cushion the lungs, while also allowing them to expand and contract during breathing.
13.
In long bones, the process whereby cartilage cells are replaced by bone cells, organic matrix is laid down, and calcium and phosphate are deposited is known as
Correct Answer
B. Endochondral ossification
Explanation
Endochondral ossification is the correct answer because it is the process by which long bones develop and grow. It involves the replacement of cartilage cells with bone cells, the deposition of organic matrix, and the accumulation of calcium and phosphate. This process is essential for the formation and development of the diaphysis (shaft) of long bones. Intramembranous ossification, on the other hand, is the process by which flat bones, such as the skull, are formed. Osteoporosis is a condition characterized by a decrease in bone density, erythropoiesis is the production of red blood cells, and diaphyseal formation is not a recognized term in bone development.
14.
What kind of joint, is described by the following: joint cavity present; bone ends covered by cartilage; may be separated by a disk; freely movable?
Correct Answer
B. Diarthrotic
Explanation
The correct answer is diarthrotic. Diarthrotic joints, also known as synovial joints, have a joint cavity present and the bone ends are covered by cartilage. These joints are freely movable and may be separated by a disk. This type of joint allows for a wide range of movement and is commonly found in the limbs.
15.
Which of the following is NOT associated with a skeletal muscle?
Correct Answer
C. Intercalated disk
Explanation
The intercalated disk is not associated with skeletal muscles. Intercalated disks are unique structures found in cardiac muscle tissue, not in skeletal muscle tissue. These disks play a crucial role in coordinating the contraction of cardiac muscle cells, allowing them to function as a synchronized unit. In contrast, skeletal muscles do not have intercalated disks. Skeletal muscles are characterized by the presence of sarcolemma, myofibrils, actin and myosin, and mitochondria, which are all involved in muscle contraction and energy production.
16.
Actin and myosin are proteins contained within a
Correct Answer
A. Myofibril
Explanation
Actin and myosin are proteins that are primarily found within myofibrils. Myofibrils are thread-like structures within muscle cells that are responsible for muscle contraction. These structures are composed of repeating units called sarcomeres, which contain actin and myosin filaments. Actin and myosin work together to generate the force needed for muscle contraction. Therefore, the correct answer is myofibril.
17.
A single motor neuron and the muscle cells supplied by its axon branches is termed
Correct Answer
C. A motor end plate
Explanation
A motor end plate is the correct answer because it refers to the specialized region of the muscle fiber membrane that forms a synapse with the axon terminal of a motor neuron. This synapse allows for the transmission of signals from the motor neuron to the muscle fiber, leading to muscle contraction. The motor end plate is essential for the communication between the nervous system and the muscles, making it the appropriate term for a single motor neuron and the muscle cells it supplies.
18.
Which of the following glial cells are responsible for myelin formation in the central nervous system?
Correct Answer
B. Oligodendrocytes
Explanation
Oligodendrocytes are responsible for myelin formation in the central nervous system. Myelin is a fatty substance that forms a protective sheath around nerve fibers, allowing for efficient transmission of electrical signals. Oligodendrocytes extend their processes and wrap around multiple axons, forming myelin sheaths. In contrast, Schwann cells are responsible for myelin formation in the peripheral nervous system. Ependymal cells are involved in the production and circulation of cerebrospinal fluid, while microglia are immune cells that protect the central nervous system from infection and injury.
19.
Depolarization occurs with
Correct Answer
A. Transfer of sodium ions to the inside of a neuron
Explanation
During depolarization, there is a transfer of sodium ions to the inside of a neuron. This process involves the opening of sodium channels in the neuron's membrane, allowing sodium ions to flow into the cell. This influx of positive ions leads to a reversal of charge across the nerve cell membrane, making the outside of the fiber positive with respect to the inside. This change in charge is essential for the generation and propagation of nerve impulses.
20.
Conduction occurs when a stimulus reduces the membrane potential to a critical level. This level is called
Correct Answer
B. Threshold
Explanation
When a stimulus reduces the membrane potential to a critical level, it triggers a response called conduction. This critical level is referred to as the threshold. Once the threshold is reached, an action potential is generated, which allows the electrical signal to propagate along the neuron. The other options, such as summation, facilitation, and refractory period, are not directly related to the reduction of membrane potential and the initiation of conduction. Therefore, the correct answer is threshold.
21.
Which tract exerts a facilitative influence on motor neurons in the anterior horn?
Correct Answer
C. Lateral reticulospinal tract
Explanation
The lateral reticulospinal tract exerts a facilitative influence on motor neurons in the anterior horn. This tract originates from the reticular formation in the brainstem and descends to the spinal cord. It primarily enhances the activity of motor neurons, increasing muscle tone and facilitating voluntary movements.
22.
If the ventral root of a spinal nerve were sectioned what would be the result in the regions supplied by the nerve?
Correct Answer
B. Loss of motor control
Explanation
If the ventral root of a spinal nerve is sectioned, it would result in loss of motor control in the regions supplied by the nerve. The ventral root is responsible for carrying motor signals from the spinal cord to the muscles, so if it is cut, the muscles in the affected regions would not receive the necessary signals to function properly. This would lead to a loss of voluntary movement and control in those regions. Sensation, on the other hand, is carried by the dorsal root of the spinal nerve, so cutting the ventral root would not directly affect sensation.
23.
Corticospinal tract
Correct Answer
D. Fibers are descending fibers from the cells in the primary motor cortex of the frontal lobe
Explanation
The correct answer is that the fibers of the corticospinal tract are descending fibers from the cells in the primary motor cortex of the frontal lobe. This means that these fibers originate in the motor cortex of the brain and travel down to the spinal cord, where they synapse with neurons that control voluntary movement. This pathway is responsible for transmitting signals from the brain to the muscles, allowing us to consciously control our movements.
24.
The primary motor area of the brain is the
Correct Answer
A. Precentral gyrus
Explanation
The primary motor area of the brain is located in the precentral gyrus. This region is responsible for initiating voluntary movements in the body. It receives information from other areas of the brain and sends signals to the muscles, allowing us to perform various motor tasks. The postcentral gyrus, on the other hand, is the primary somatosensory area of the brain, responsible for processing sensory information such as touch and proprioception. The temporal lobe is involved in auditory processing and memory, while the occipital lobe is primarily responsible for visual processing. The hypothalamus plays a crucial role in regulating various physiological processes, but it is not directly involved in motor control.
25.
Which of the following functions are conducted in the dorsal columns of the spinal cord, that is, in the fasciculus graciles and cuneatus?
Correct Answer
E. All of the above
Explanation
The functions conducted in the dorsal columns of the spinal cord, specifically in the fasciculus graciles and cuneatus, include a high degree of location, vibratory sense, fine gradations of pressure, and kinesthesia. These functions are responsible for the perception of precise location, the ability to sense vibrations, the ability to perceive subtle variations in pressure, and the awareness of body movement and position. Therefore, all of the given options are correct.
26.
Damage to the precental gyrus of the cerebral cortex
Correct Answer
A. Spastic paralysis
Explanation
Damage to the precentral gyrus of the cerebral cortex can result in spastic paralysis. The precentral gyrus is responsible for voluntary motor control, and damage to this area can disrupt the signals that control muscle movement. Spastic paralysis refers to a condition where there is increased muscle tone and stiffness, leading to difficulties in movement. This can result in muscle spasms, stiffness, and difficulty in coordinating movements. Sensory loss, intention tremor, tremor at rest, and loss of simple reflexes are not directly associated with damage to the precentral gyrus, making them incorrect answers.
27.
Almost all sensory impulses pass through what structure on their way to the cerebral cortex?
Correct Answer
E. Thalamus
Explanation
The thalamus is a structure located in the brain that acts as a relay station for sensory information. It receives sensory impulses from various parts of the body and then sends them to the cerebral cortex, which is responsible for processing and interpreting these signals. Therefore, almost all sensory impulses pass through the thalamus on their way to the cerebral cortex. The basal ganglia, corpus striatum, hypothalamus, and corpus callosum are not directly involved in this process.
28.
Which of the following describes the function of the hypothalamus?
Correct Answer
E. All to the above describe hypothalamic functhions
Explanation
The hypothalamus is a small region in the brain that plays a crucial role in maintaining homeostasis and regulating various bodily functions. It contains temperature control centers, which help regulate body temperature. It also regulates visceral activity, such as digestion and cardiovascular function. The hypothalamus is responsible for the synthesis and release of hormonal releasing factors, which control the release of hormones from the pituitary gland. Additionally, it influences basic drives like sex, thirst, and hunger. Therefore, all of the above options accurately describe the functions of the hypothalamus.
29.
Important centers for control of respiration and dardiovascular function are located in the
Correct Answer
B. Medulla
Explanation
The medulla is the correct answer because it is a vital part of the brainstem that controls essential functions such as respiration and cardiovascular function. It contains nuclei that regulate the rate and depth of breathing, as well as control blood pressure and heart rate. Damage to the medulla can lead to severe respiratory and cardiovascular problems, highlighting its crucial role in maintaining these vital functions. The pons, midbrain, and thalamus are also important regions of the brain, but they do not have the same level of control over respiration and cardiovascular function as the medulla does.
30.
Which of the following is/are not necessary for any of the responses referred to as reflexes?
Correct Answer
B. Cerebral cortex
Explanation
The cerebral cortex is not necessary for any of the responses referred to as reflexes. Reflexes are automatic responses to stimuli that do not involve conscious thought or decision-making. They are controlled by the spinal cord and lower brain centers, bypassing the cerebral cortex. The autonomic nerves, effectors, receptors, and synapses are all involved in the reflex arc, which allows for the rapid and involuntary response to a stimulus.
31.
A type of receptor which is sensitive to pain is
Correct Answer
C. Free nerve endings
Explanation
Free nerve endings are the type of receptors that are sensitive to pain. These nerve endings are found throughout the body and are responsible for detecting and transmitting pain signals to the brain. They are the most common type of pain receptors and can be found in the skin, muscles, and organs. When these nerve endings are stimulated by factors such as tissue damage or inflammation, they send signals to the brain, resulting in the perception of pain.
32.
The autonomic nervous system exerts its influence on
Correct Answer
D. All of the above
Explanation
The autonomic nervous system is responsible for regulating involuntary bodily functions. It controls smooth muscle, which is found in organs such as the intestines and blood vessels, allowing them to contract and relax. It also regulates glandular secretion, controlling the release of hormones and other substances. Additionally, the autonomic nervous system controls the contraction and relaxation of cardiac muscle, which is responsible for the beating of the heart. Therefore, the correct answer is "all of the above" as the autonomic nervous system exerts its influence on smooth muscle, glandular secretion, and cardiac muscle.
33.
The neurotransmitter substance released at the postganglionic terminal of the parasympathetic division of the autonomic nervous system is
Correct Answer
D. Acetylcholine
Explanation
The correct answer is acetylcholine. Acetylcholine is the neurotransmitter substance released at the postganglionic terminal of the parasympathetic division of the autonomic nervous system. It is responsible for transmitting signals from the nerve endings to the target organs, leading to parasympathetic responses such as rest and digest.
34.
Norepinephrine and epinephrine are released from
Correct Answer
C. Postganglionic fibers of the sympathetic nervous system and the adrenal medulla
Explanation
Norepinephrine and epinephrine are released from postganglionic fibers of the sympathetic nervous system and the adrenal medulla. These neurotransmitters are involved in the "fight or flight" response, helping to increase heart rate, blood pressure, and energy production. The sympathetic nervous system activates these responses by releasing norepinephrine at the postganglionic fibers, while the adrenal medulla releases epinephrine into the bloodstream. This dual release allows for a widespread and rapid response throughout the body in times of stress or danger.
35.
All of the following are autonomic effects on the body except regulation of
Correct Answer
C. Skeletal muscle tone
Explanation
The autonomic nervous system regulates various involuntary functions in the body. Heart rate, digestive secretion, glandular secretion, and blood pressure are all examples of autonomic effects. However, skeletal muscle tone is not directly regulated by the autonomic nervous system. Instead, it is controlled by the somatic nervous system, which is responsible for voluntary movements.
36.
Extreme excitement in a patient may have the following effects on organ systems:
Correct Answer
D. A and C
Explanation
Extreme excitement in a patient can lead to increased blood pressure and relaxation of smooth muscles in the bronchi. Increased blood pressure is a common physiological response to excitement and can be caused by the release of stress hormones such as adrenaline. Relaxation of smooth muscles in the bronchi can result in bronchodilation, allowing for easier breathing. These effects on the organ systems are represented by options A and C.
37.
An increase in parasympathetic activity
Correct Answer
D. All of the above
Explanation
An increase in parasympathetic activity can lead to various physiological changes. It stimulates salivation, which is the production of saliva in the mouth. It also increases gastrointestinal activity, which involves the movement and digestion of food in the digestive system. Additionally, parasympathetic activity decreases heart rate, promoting a slower heart rhythm. Therefore, all of the above options are correct as they represent the effects of increased parasympathetic activity.
38.
Hormones
Correct Answer
C. Are chemical substances that are produced by endocrine glands, travel through the circulatory system, and exert their influence on specific structures
Explanation
Any time during a test, if you don't know the right answer: 1. find a answer that grammatically fits better with the question
2. the longest answer
3. or just pick C
39.
A topic hormone
Correct Answer(s)
A. Stimulates growth and secretion of a specific glandular tissue
D. Two of the above
Explanation
The correct answer is "stimulates growth and secretion of a specific glandular tissue, two of the above." This answer is correct because a topic hormone can indeed stimulate the growth and secretion of a specific glandular tissue. Additionally, it can act by positive feedback control. However, it is not necessarily produced by the gonads, so only two of the given options are true.
40.
Calcium homeostasis is maintained by
Correct Answer
C. Parathyroid hormone and calcitonin
Explanation
Parathyroid hormone and calcitonin are both involved in maintaining calcium homeostasis. Parathyroid hormone increases blood calcium levels by stimulating the release of calcium from bones, increasing calcium reabsorption in the kidneys, and stimulating the production of active vitamin D, which enhances calcium absorption in the intestines. On the other hand, calcitonin decreases blood calcium levels by inhibiting the release of calcium from bones and increasing calcium excretion in the kidneys. Together, these hormones work to regulate calcium levels in the body and ensure that they remain within a narrow range.
41.
Calcitonin
Correct Answer
E. Only B and C are correct descriptions
Explanation
Calcitonin is a hormone that is secreted by the thyroid gland. It is released in response to excess serum calcium levels in the body. It helps to lower blood calcium levels by inhibiting the activity of osteoclasts, the cells responsible for breaking down bone tissue. Therefore, the correct answer is that only statements B and C are correct descriptions of calcitonin.
42.
Which hormone is LESS involved in a stress reaction?
Correct Answer
D. Thyroxin
Explanation
Thyroxin is less involved in a stress reaction compared to the other hormones listed. Epinephrine and norepinephrine are both released during stress and are responsible for the "fight or flight" response. Cortisone, also known as cortisol, is a stress hormone that helps regulate the body's response to stress. Adrenocorticotropin (ACTH) is a hormone that stimulates the release of cortisol. Thyroxin, on the other hand, primarily regulates the body's metabolism and is not directly involved in the stress response.
43.
Cortisol
Correct Answer
D. All of the above
Explanation
Cortisol is a hormone that plays a crucial role in the body's response to stress. It has several effects on metabolism, including increasing the flux of amino acids, mobilizing stored fat, and promoting gluconeogenesis (the production of glucose from non-carbohydrate sources). These actions help provide the body with the necessary resources to cope with stress and maintain energy levels. Therefore, all of the given options (increasing amino acid flux, mobilizing stored fat, and promoting gluconeogenesis) are correct effects of cortisol.
44.
Insulin has all of the following effects EXCEPT
Correct Answer
D. Promotes liver glycogenolysis, therefor has a hyperglycemic effect
Explanation
Insulin is a hormone produced by the pancreas that helps regulate blood sugar levels. It promotes glucose entry into cells, which lowers blood sugar levels and has a hypoglycemic effect. Insulin also promotes the transport of amino acids into cells, increasing protein synthesis, and the transport of fatty acids into cells, resulting in a lipogenic effect. Additionally, insulin promotes potassium entry into cells, leading to a hypokalemic effect. However, insulin does not promote liver glycogenolysis, which is the breakdown of glycogen into glucose. Therefore, it does not have a hyperglycemic effect.
45.
Antidiuretic hormone is released in direct response to
Correct Answer
C. Hyperosmolarity of extracellular fluids
Explanation
Antidiuretic hormone is released in response to hyperosmolarity of extracellular fluids. Antidiuretic hormone, released by the posterior lobe of the the pituitary gland, increases renal reabsorption and retention of water to dilute body fluids that are too concentrated. Antidiuretic hormone is also known as vasopressin
46.
Aldosterone
Correct Answer
B. Increases reabsorption of sodium and secretion of potassium
Explanation
Aldosterone is a hormone produced by the adrenal glands that plays a crucial role in regulating electrolyte balance and blood pressure. One of its main functions is to increase the reabsorption of sodium in the distal tubule of the kidney, which helps to retain sodium and water in the body. Additionally, aldosterone also stimulates the secretion of potassium in the distal tubule, which helps to maintain the balance of potassium levels in the body. Therefore, the correct answer is that aldosterone increases reabsorption of sodium and secretion of potassium.
47.
Ovulation
Correct Answer
A. Is dependent on a high concentration of LH in the blood
Explanation
Ovulation is dependent on a high concentration of LH in the blood. LH, or luteinizing hormone, is responsible for triggering the release of an egg from the ovary during ovulation. When the LH levels rise, it signals the ovary to release a mature egg, which can then be fertilized by sperm. Therefore, the presence of a high concentration of LH in the blood is necessary for ovulation to occur.
48.
Which of the following secretes progesterone?
Correct Answer
B. Corpus luteum
Explanation
The corpus luteum secretes progesterone. Progesterone is a hormone that plays a crucial role in the menstrual cycle and pregnancy. It helps prepare the uterus for implantation of a fertilized egg and maintains the uterine lining during pregnancy. The corpus luteum is a temporary structure that forms in the ovary after the release of an egg during ovulation. If fertilization occurs, the corpus luteum continues to produce progesterone to support early pregnancy. If fertilization does not occur, the corpus luteum breaks down, leading to a decrease in progesterone levels and the start of a new menstrual cycle.
49.
With inspiration
Correct Answer
C. Volume of the lungs increases, pressure decreases
Explanation
As the size of the thorax and lungs increases, the pressure within the lungs decreases to a level below that of air according to Boyle's Law. The pressure that is decreased is intrapulmonic pressure
50.
During inspiration
Correct Answer
C. Intrapleural pressure increases while intraalveolar pressure decreases
Explanation
During inspiration, the diaphragm and external intercostal muscles contract, causing the volume of the thoracic cavity to increase. This increase in volume leads to a decrease in intrapleural pressure, as the pleural space expands. At the same time, the expansion of the thoracic cavity also leads to an increase in the volume of the alveoli in the lungs. This increase in volume causes a decrease in intraalveolar pressure. Therefore, during inspiration, intrapleural pressure increases while intraalveolar pressure decreases.