1.Dental Hygiene Board Review

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.

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.

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.

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.

type O = universal donor, type AB = universal recipient

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.

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.

Thrombocyte is not a leukocyte because it is actually a type of blood cell called a platelet. Leukocytes, on the other hand, are white blood cells that play a crucial role in the immune system. Neutrophil, eosinophil, basophil, and monocyte are all types of leukocytes involved in various immune responses.

The pressoreceptor system responds to an increase in blood pressure at the area of the aortic arch and carotid bodies. It operates through the vasomotor center, which regulates blood pressure. In response to increased blood pressure, the pressoreceptor system decreases the heart rate, strength of contraction, and peripheral resistance. Therefore, all of the above statements are correct.

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.

The correct answer is that all statements correctly describe pressure points. This means that each of the given statements accurately identifies a pressure point and its corresponding artery. The first statement states that the carotid arteries to the head can be found inferior to the angle of the mandible. The second statement states that the facial artery to the face can be found at the inferior border of the angle of the mandible at the junction of the medial and lateral thirds. The third statement states that the subclavian artery to the arm can be found superior and deep to the clavicle. The fourth statement states that the branchial artery to the lower arm can be found on the medial side of the humerus. Therefore, all of these statements correctly describe pressure points.

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.

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.

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.

The correct answer explains the sequence of blood flow through the heart and the circulatory system. It starts with the inferior vena cava, which brings deoxygenated blood from the body to the right atrium. From there, the blood flows through the tricuspid valves into the right ventricle. The blood is then pumped into the pulmonary trunk, which leads to the pulmonary circulation in the lungs. After oxygenation in the lungs, the blood returns to the heart via the pulmonary veins, entering the left atrium. It then passes through the bicuspid valves into the left ventricle. Finally, the oxygenated blood is pumped out of the heart through the ascending aorta to the systemic circulation.

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.

Digestion refers to the process of breaking down large chemical compounds present in food into simpler substances through hydrolysis. This allows for the absorption of small molecular weight end products into body fluids. Therefore, the correct answer is "only A and C" as it includes both the splitting of large chemical compounds and hydrolysis, which are essential processes in digestion.

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.

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.

Amylase is the correct answer because it is an enzyme that specifically hydrolyzes polysaccharides. Polysaccharides are complex carbohydrates made up of multiple sugar molecules bonded together. Amylase breaks down these polysaccharides into smaller sugar molecules through a process called hydrolysis. Lipase, protease, trypsin, and pepsin are enzymes that are involved in the digestion of lipids, proteins, and peptides respectively, but they do not hydrolyze polysaccharides.

The sympathetic innervation to the face and head structures is transmitted via nerves that have cells of origin in the superior cervical ganglion. This ganglion is located in the neck region and is responsible for sending sympathetic signals to various structures in the face and head. The sympathetic nervous system helps regulate various bodily functions including blood pressure, heart rate, and pupil dilation. By having cells of origin in the superior cervical ganglion, the sympathetic nerves can efficiently transmit signals to the face and head structures, allowing for appropriate physiological responses in these areas.

The rate of gastric emptying is affected by multiple factors. Firstly, the quantity of liquid in chyme plays a role in determining how quickly the stomach empties its contents. Secondly, neural and hormonal reflexes from the small intestine also influence gastric emptying rate. Finally, the quantity of chyme present in the small intestine affects the rate at which the stomach empties. Therefore, all of the above factors (A and C) have an impact on the rate of gastric emptying.

Bile is formed in the liver and stored in the gallbladder

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.

Mean arterial blood pressure is regulated by neural mechanisms that control constriction of the arteries, principles of capillary dynamics, and renal and hormonal mechanisms. In addition, mean arterial pressure (the approximate average of systolic and diastolic pressures) is affected by the cardiac output. Cardiac output is the volume of blood the heart pumps per minute.

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.

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.

Antidiuretic hormone (ADH) regulates the reabsorption of water in the distal convoluted tubules and collecting ducts. ADH is released by the posterior pituitary gland in response to low blood volume or high blood osmolarity. It acts on the cells lining the distal convoluted tubules and collecting ducts, increasing their permeability to water. This allows more water to be reabsorbed back into the bloodstream, reducing urine output and helping to maintain water balance in the body.

The statement that if a person tests HIV negative, their blood and body fluids will contain the virus is incorrect. When a person tests negative for HIV, it means that the virus is not present in their blood or body fluids at the time of testing. Testing negative for HIV indicates that the person is not infected with the virus.

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.

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.

Oxygen is carried in the blood both as oxyhemoglobin and dissolved in plasma. Oxyhemoglobin is formed when oxygen binds to hemoglobin molecules in red blood cells. This allows for efficient transport of oxygen from the lungs to the body tissues. Additionally, a small amount of oxygen can dissolve directly in the plasma, allowing for a small fraction of oxygen to be transported this way. Therefore, both A (oxyhemoglobin) and B (dissolved in plasma) are correct answers.

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.

The oculomotor nerve is responsible for constriction of the pupil of the eye. This nerve controls the muscles that regulate the size of the pupil, allowing it to constrict or dilate in response to changes in light intensity or visual focus. The optic nerve, on the other hand, is responsible for transmitting visual information from the eye to the brain. The abducens nerve controls the lateral movement of the eye, while the vagus nerve is primarily involved in regulating functions of the internal organs.

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.

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

The respiratory tidal volume refers to the amount of air that is exchanged in the lungs during a normal breath. It is the volume of air that is inhaled and exhaled during each respiratory cycle. This measurement is typically around 1 liter in adults.

Cardiac output refers to the amount of blood that the heart pumps per minute. It is determined by the heart rate, which is the number of times the heart beats per minute, and the stroke volume, which is the amount of blood pumped out of the heart with each beat. Therefore, the correct answer is "heart rate and stroke volume" because these two factors directly contribute to the calculation of cardiac output.

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.

Amylase is an enzyme that hydrolyzes carbohydrates.

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.

The pulmonary valve prevents the backflow of deoxygenated blood from the right ventricle into the right atrium, while the right atrioventricular (tricuspid) valve prevents the backflow of deoxygenated blood from the right ventricle into the right atrium. Therefore, the correct answer is pulmonary and right atrioventricular valves.

The kidney plays a crucial role in maintaining the balance of various substances in the body. It regulates hydrogen ion concentration, body fluid volumes, serum sodium levels, and removes metabolic end products like urea and creatinine. However, the regulation of serum calcium levels is primarily controlled by the parathyroid gland and bone. The parathyroid gland releases parathyroid hormone (PTH) to regulate calcium levels in the blood. Therefore, the kidney does not directly regulate serum calcium levels, making it the exception among the given options.

The parasympathetic innervation to the lacrimal glands and the secretory glands of the nose and palate is transmitted via the facial nerve. The facial nerve carries the parasympathetic fibers that control the production of tears and the secretion of mucus in the nose and palate. This nerve also controls the muscles of facial expression and carries taste sensations from the anterior two-thirds of the tongue.

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.

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.

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.

The swallowing mechanism involves the activation of multiple cranial nerves. The trigeminal nerve is responsible for the sensation in the face and mouth during swallowing. The facial nerve controls the muscles responsible for closing the eyes and lips during swallowing. The glossopharyngeal nerve innervates the muscles of the pharynx and helps in initiating the swallowing reflex. The vagus nerve plays a crucial role in coordinating the muscles of the throat and esophagus during swallowing. Lastly, the hypoglossal nerve controls the movement of the tongue, which is essential for pushing the food back into the throat. Therefore, all of these cranial nerves are involved in the swallowing mechanism.

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.

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.