oooo
96.How many permanent anterior teeth are present in an adult mouth? A 6 B 8 C 10 D 12
) and 4 canines (two in each arch). Figures in choices A, B, and C are less than 12 (the normal number of permanent anterior teeth).
2. During periodontal surgery, a fenestration is exposed on tooth #6. A fenestration is a defect of which type of bone? A Compact B Cancellous C Interdental D Interradicular
A fenestration is an opening or window in the solid plate of compact (A) cortical bone on the facial surface over the root of a tooth. Cancellous(B) bone is located between the alveolar bone proper and the plates of cortical bone. The interdental septum (C) is bone located between the roots of adjacent teeth. Interradicular (D) bone is located between the roots of the same tooth.
54.Which of the following cells is/are DIRECTLY responsible for immunoglobulin production? A Plasma B Basophils C Monocytes D Neutrophils E Eosinophils
Activated B-cell lymphocytes form plasma cells (A), which are directly responsible for producing immunoglobulins (antibodies). Basophils (B), monocytes (C), neutrophils (D), and eosinophils (E) are all white blood cells, and all contribute to the immune response. A lymphocyte is a white blood cell that has three functional types, one of which is a B- cell lymphocyte.
73.Match each cell type to the structure it forms. Cell Type Resulting Structure 1. Ameloblasts A. Cementum 2. Cementoblasts B. Dentin 3. Odontoblasts C. Alveolar bone 4. Dental follicle D. Enamel
Ameloblasts (1) give rise to enamel (D). Cementoblasts (2) give rise to cementum (A). Odontoblasts (3) give rise to dentin (B). The dental follicle (4) gives rise to mesenchymal cells, which give rise to alveolar bone (C), the periodontal ligament, and cementum
two in each arch
An adult mouth has 12 total permanent anterior teeth (D): 8 incisors (4 each lateral and central incisors
83.There is relatively constant mesial movement of the molars to compensate for proximal abrasion. Relatively consistent occlusal forces result in bone remodeling. A Both statements are correct and related. B Both statements are correct but NOT related. C The first statement is correct, but the second is NOT. D The first statement is NOT correct, but second is correct. E Both statements are incorrect and unrelated.
Both statements are correct and related (A). Active eruption, mesial drift, and masticatory occlusal and orthodontic corrective forces are all examples of consistent forces in alveolar bone remodeling. Traumatic occlusal force is an example of a type of force that is NOT a consistent, constant force that results in bone remodeling. Choices B, C, D, and E do not correctly reflect the statements.
61.The incomplete developmental division of a tooth germ is called FUSION. Fusion takes place during the initiation stage of tooth development. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.
Both statements are false (B). Fusion is the union of two tooth germs.Incomplete tooth germ division is referred to as GEMINATION. Fusion takes place during the cap stage of odontogenesis, not during the initiation stage. Choices A, C, and D do not accurately reflect the statements.
82.The clinical crown-to-root ratio is always the same. However, the anatomic crown-to-root ratio may change. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.
Both statements are false (B). The clinical crown-to- root ratio may change, depending on the location of alveolar bone and the gingiva. The anatomic crown-to-root ratio (the crown and root are covered with enamel and cementum, respectively) always remains the same. Choices A, C, and D do not correctly reflect the statements.
7. The ophthalmic nerve is the first division of the fifth cranial nerve V, the trigeminal nerve. The maxillary nerve is the second division of the trigeminal nerve. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.
Both statements are true (A). Cranial nerve V is the trigeminal nerve, of which the ophthalmic nerve is the first division (V1) and the maxillary nerve is the second division (V2). The third division of the trigeminal nerve (V3) is the mandibular nerve. Choices B, C, and D do not accurately reflect the statements.
84.Enamel is formed by ameloblasts, which are derived from the ectoderm. The ectoderm also signals the mesoderm to start the development of dentin and pulp. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.
Both statements are true (A). Enamel develops from the enamel organ, which is derived from the ectoderm. The enamel organ will differentiate into the inner enamel epithelium, the stellate reticulum, the stratum intermedium, and the outer enamel epithelium. The inner enamel epithelium will give rise to ameloblasts. The ectoderm's production of ameloblasts is the signal to the mesodermal structure of the dental papilla to start the formation of dentin and pulp. Choices B, C, and D do not correctly reflect the statements.
94.Enamel may be lost through attrition, abrasion, erosion, caries, or abfraction. Radiographically, enamel appears more radiolucent than dentin or pulp, both of which appear more radiopaque. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.
Choice C is correct. The first statement is true. Enamel may be lost through attrition (wearing away from tooth-to-tooth contact), abrasion (loss through friction from toothbrushing or toothpaste), erosion (loss through chemical means that do not involve bacteria), caries (loss through chemical means from cariogenic bacteria), or abfraction (loss through tensile and compressive forces during tooth flexure). However, the second statement is false. On radiographs, enamel appears more radiopaque (lighter) than dentin or pulp, both of which appear more radiolucent (darker). Choices A, B, and D do not accurately reflect the statements.
44. The first branchial arch is also called the mandibular arch. The cartilage forming within the mandibular arch is known as Reichert cartilage. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.
Choice C is correct; the first statement is true, and the second statement is false. There are six branchial arches. The first branchial arch is considered the mandibular arch, and the second branchial arch is known as the hyoid arch. The cartilage that forms within the mandibular arch is Meckel cartilage, not Reichert cartilage, which forms in the second branchial arch. Choices A, B, and D do not correctly reflect the statements.
25. The muscles of facial expression are innervated by which nerve? A IV B V C VII D VIII
Cranial nerve VII (C), the facial nerve, innervates the muscles of facial expression. Cranial nerve IV (A), the trochlear nerve, serves as an efferent nerve for a muscle of the eye. Cranial nerve V (B), the trigeminal nerve, serves as an afferent nerve to the oral cavity, teeth, and most of the skin of the face and head, as well as efferent innervations for the muscles of mastication and some of the muscles of the palate. Cranial nerve VIII (D), the vestibulocochlear nerve, is an afferent nerve for hearing and balance.
23. Which cranial nerve provides parasympathetic innervation to the cardiac muscles, thymus, and stomach? A IV B X C XI D XII
Cranial nerve X (B), the vagus nerve, sends parasympathetic fibers to many organs, including the thymus and the muscles of the heart and stomach. Cranial nerve IV (A), the trochlear nerve, serves as an efferent nerve for a muscle of the eye. Cranial nerve XI (C), the accessory nerve, serves as an efferent nerve for various muscles of the head and neck. Cranial nerve XII (D), the hypoglossal nerve, innervates intrinsic and extrinsic muscles of the tongue.
5. Which component of a nerve conducts impulses toward the cell body? A Axon B Soma C Neuron D Dendrite
Dendrites (D) are branching cellular extensions of a nerve that conduct impulses toward the cell. An axon (A) is a cellular extension of a nerve that conducts impulses away from the cell. The soma (B) is the body of the cell containing the nucleus. A neuron (C) is the basic functional unit of the nervous system.
78.Which is NOT a characteristic feature of the primary dentition? A Thin enamel B Thin dentin C Large pulp cavity D Whiter in color than permanent dentition
Dentin in primary teeth is much thicker than dentin in permanent teeth (B). Primary teeth are characterized as having relatively thin enamel (A) and large pulp cavities (C) and are whiter in color than permanent teeth (D).
69. For each division of the trigeminal nerve (V) listed, select its appropriate name from the list provided. Trigeminal Nerve DivisionName 1. Division I A. Maxillary 2. Division II B. Mandibular 3. Division III C. Ophthalmic
Division I (1) is known as the ophthalmic V1 (C). Division II (2) is the maxillary V2 (A). Division III (3) is the mandibular V3 (B).
60.Down syndrome is a developmental disturbance that occurs during which period of prenatal development? A Fetal B Embryonic C Preimplantation
Down syndrome is a developmental disturbance that occurs during meiosis. The final stages of meiosis occur just after fertilization, which takes place during the preimplantation (C) period. The division of chromosomes occurs prior to the zygote being implanted and has already taken place by the embryonic (B) or fetal (A) periods.
81.Match each dental anomaly listed with its description. Dental AnomalyDescription 1. Dw arf roots A. Partial splitting of tooth germ 2. Concrescence B. Crow n or root demonstrating sharp bends, curves 3. Dilaceration C. Fusion after root formation 4. Mulberry molars D. Extreme condition impacting crow n-to-root ratio 5. Gemination E.Result of congenital syphilis 6. Dens in dente F Tooth w ithin a tooth
Dwarf roots (1) affect the crown-to-root ratio (D). Concrescence (2) involves fusion after roots are formed (C). In dilaceration (3), the crown or root demonstrates sharp bends or curves (B). Mulberry molars (4) result from congenital syphilis (E). Gemination (5) involves the partial splitting of the root germ (A). Dens in dente (6) describes a tooth within a tooth (F).
43. For each numbered temporomandibular joint (TMJ) disk position, select the most closely linked description of the movement from the list provided. TMJ Disk Positions Movement 1.Elevation A. Shifting the mandible to one side by unilateral contraction of the lateral pterygoid muscle 2. Lateral deviation B. Opening the mouth by contraction of the inferior heads of the lateral pterygoid muscles and the suprahyoid muscles 3. Retraction C. Moving the jaw forw ard by bilateral contraction of the lateral pterygoid muscles 4. Protrusion D. Raising the low er jaw by contraction of all portions of the temporalis, masseter, and medial pterygoid muscles 5. Depression E. Moving the jaw back by contraction of the posterior portions of both temporalis muscles
Elevation of the TMJ disk (1) results in the raising of the lower jaw through contraction of all portions of the temporalis, masseter, and medial pterygoid muscles (D). Lateral deviation of the TMJ disk (2) results in shifting of the mandible to one side via unilateral contraction of the lateral pterygoid muscle (A). Retraction of the TMJ disk (3) results in backward jaw movement through contraction of posterior portions of both temporalis muscles (E). Protrusion of the TMJ disk (4) produces forward jaw movement through bilateral contraction of the lateral pterygoid muscles (C). Depression of the TMJ disk (5) produces opening of the mouth through contraction of the inferior heads of the lateral pterygoid and suprahyoid muscles (B).
57.From the following list, select the structures of the embryo that begin development in week 4 of prenatal development. A Face B Neck C Palate D Tongue E Placenta
Facial development (A) begins during week 4 and continues into week 12. The neck (B) and the tongue (D) begin to develop in conjunction with the face. The placenta (E) begins development during week 2 from the interaction of the trophoblast layer and the endometrial tissues. The palate (C) begins formation during week 5 and also continues through week 12.
55.Incremental lines that stain brown in preparations of mature enamel are A neonatal lines. B enamel tufts. C lines of Retzius. D enamel spindles. E enamel lamellae.
Incremental lines that stain brown in preparations of mature enamel are lines of Retzius (C). The neonatal line (A) is an incremental line of Retzius; however, it is more pronounced and marks trauma or stress placed on ameloblasts during birth. Enamel tufts (B) appear as small, dark hypocalcified, brushlike areas found near the dentinoenamel junction (DEJ). Enamel spindles (D) are actually short dentinal tubules that have been trapped in the enamel matrix. Enamel lamellae (E) extend from the DEJ all the way out to the occlusal surface and are partially calcified sheets of enamel matrix.
52.Which primordial structure differentiates into the ameloblasts that produce enamel? A Outer enamel epithelium B Stellate reticulum C Inner enamel epithelium D Stratum intermedium
Inner enamel epithelium (IEE) (C) comprises the columnar cells of the enamel organ that differentiate into ameloblasts. The outer enamel epithelium (OEE) (A) comprises cuboidal cells that protect the outer portion of the enamel organ. Between the IEE and OEE is the stellate reticulum (B), composed of star-shaped cells, and the stratum intermedium (D), composed of flat to cube-shaped cells; both support the production of enamel.
90.Which gland is associated with dry eye syndrome, (DES), also known as keratoconjunctivitis sicca? (KCS)? A Thyroid B Thymus C Lacrimal D Parathyroid
Lacrimal glands (C) are paired exocrine glands that secrete lacrimal fluid, or tears. With dry eye syndrome, the lacrimal glands produce less fluid, a condition often associated with aging or certain medications. The thyroid (A), thymus (B), and parathyroid (D) glands are all endocrine glands, not exocrine glands. The thyroid gland (A) is the largest endocrine gland and secretes thyroxine directly into the vascular system to stimulate the body's metabolic rate. The thymus gland (B) is part of the immune system and helps fight disease processes. The parathyroid gland (D) secretes parathyroid hormone directly into the vascular system to regulate phosphorus and calcium levels.
32. Which of the following arteries supplies maxillary anterior teeth with blood? A Incisive B Mylohyoid C Greater palatine D Anterior superior alveolar
Maxillary anterior teeth are supplied by the anterosuperior alveolar artery (D). The incisive artery (A) supplies the periodontium of the mandibular anterior teeth, including the associated gingiva. The mylohyoid artery (B) supplies the floor of the mouth and the mylohyoid muscle. The greater palatine artery (C) supplies the hard and soft palates.
85.Cellular metabolism occurs in the A ribosomes. B lysosome. C mitochondria. D Golgi apparatus. E endoplasmic reticulum.
Mitochondria (C) are the "power plants" of the cell and are responsible for the rate of energy production. Ribosomes (A) are the RNA (ribonucleic acid) of the cell and are also responsible for protein production. Lysosomes (B) act as "scavenger" cells, removing debris from within the cellular body. The Golgi apparatus (D) is involved in merocrine secretion. The endoplasmic reticulum (E) manufactures various products for use within and outside cells.
93.Each is a type of connective tissue EXCEPT one. Which one is the EXCEPTION? A Bone B Blood C Muscle D Cartilage
Muscle tissue (C) is part of the muscular system and is a classification of basic tissue in the same way that connective tissue is also a classification of basic body tissue. Bone (A) is a rigid type of specialized connective tissue that makes up the majority of the body's mature skeleton. Blood (B) is a fluid specialized connective tissue that transports nutrients throughout the body. Cartilage (D) is a type of firm, noncalcified, specialized connective tissue that forms much of the temporary skeleton of the embryo and structurally supports certain soft tissues after birth.
46.Which cells are responsible for producing dentin? A Osteoblasts B Ameloblasts C Odontoblasts D Cementoblasts
Odontoblasts (C) are responsible for producing dentin. Osteoblasts (A) are bone-producing cells. Ameloblasts (B) produce enamel and cementoblasts (D) produce cementum.
48.Order the stages of odontogenesis. Match each letter with its proper sequence number. A Cap stage B Bud stage C Bell stage D Maturation stage E Initiation stage
Odontogenesis begins with the initiation stage (1E) during the sixth to the seventh week. Next is the bud stage (2B), beginning in the eighth week, which is followed by the cap stage (3A) during weeks nine and ten. During the eleventh and twelfth weeks, the bell stage (4C) occurs, and the final stage of odontogenesis is the maturation stage (5D).
3. The fibrous connective tissue membrane covering the outside of bone is called the A endosteum. B periosteum. C hyaline cartilage. D articular cartilage.
Periosteum (B) is the fibrous connective tissue membrane covering the outside of bone except at the articular surfaces. Endosteum (A) is the connective tissue membrane lining the marrow cavity of the bone. Hyaline cartilage (C) is a flexible and slightly elastic cartilage found in joints, costal cartilages, the nasal septum, the larynx, and the trachea. Articular cartilage (D) is specialized, thin, smooth hyaline cartilage found on the joint surfaces of bones, for example, in a synovial joint.
79.Which teeth have wider crowns mesiodistally than faciolingually? A #5 and #12 B #7 and #10 C #24 and #25 D #23 and #26
Permanent maxillary incisors, teeth #7 and #10 (B), are wider mesiodistally than faciolingually. Maxillary premolars (A) and mandibular incisors (C and D) are wider faciolingually than mesiodistally.
80.Each is an important function of the cementoenamel junction (CEJ) EXCEPT one. Which one is the EXCEPTION? A Prevention of caries B Self-cleansing properties C Food deflection resulting in gingival inflammation D Health and maintenance of periodontal tissue in interproximal spaces
Prevention of caries decay (A) is NOT a function of the cementoenamel junction (CEJ). The CEJ functions for self-cleansing by the natural spillways that are formed, lending to self-cleansing properties (B), food deflection (C), and both health and maintenance of periodontal tissues in the interproximal spaces (D).
22. Which of the following are the two main divisions or systems of the autonomic nervous system? A Brain, spinal cord B Afferent impulse, efferent impulse C Sympathetic system, parasympathetic system
Sympathetic and parasympathetic (C) systems are the two divisions of the autonomic nervous system. The brain and the spinal cord (A) are structures within the central nervous system. Afferent impulse is the sensory nerve impulse traveling toward the central nervous system, and efferent impulse is the motor nerve impulse traveling to the muscles that will move in response (B).
16. Which endocrine gland matures T-lymphocytes for the immune system and undergoes involution (reduces in size) after puberty? A Thyroid B Thymus C Pancreas D Parathyroid
T-lymphocytes are processed in the thymus (B), where they attain their mature function. The thymus is large in infancy and shrinks after puberty. The thyroid gland (A) produces two main hormones— thyroxine (T4) and triiodothyronine (T3)—that circulate through the bloodstream and have many effects on body metabolism, growth, and development. The islet cells of the pancreas (C) create and release important hormones directly into the bloodstream. Two of the main pancreatic hormones are insulin, which acts to lower blood sugar, and glucagon, which acts to raise blood sugar. Maintaining proper blood sugar levels is crucial to the functioning of key organs, including the brain, liver, and kidneys. The pancreas also has an exocrine function in producing enzymes that aid digestion. The parathyroid glands (D) regulate calcium levels by secreting parathyroid hormone and calcitonin into the bloodstream.
13. Teeth #3 and #14 are A ipsilateral to each other. B contralateral to each other. C inferior to each other. D superficial to each other.
Teeth #3 and #14 are the first maxillary molars on the opposite arches of the mouth, which means that they are contralateral to each other (B). Ipsilateral (A) would mean that they are on the same side. Inferior (C) applies to a structure that is beneath or lower than another structure, and superficial (D) applies to a structure that is near the surface. These are not terms used to describe the dentition.
97.Which tooth numbers represent maxillary first premolars? A #5 and #12 B #4 and #13 C #21 and #28 D #24 and #25
Teeth #5 and #12 (A) are maxillary first premolars. Teeth #4 and #13 (B) are maxillary second premolars. Teeth #21 and #28 (C) are mandibular first premolars. Teeth #24 and #25 (D) are mandibular central incisors.
49.Division of a cell into two daughter cells occurs during which phase of mitosis? A Prophase B Anaphase C Metaphase D Telophase
Telophase (D) is the last phase in which the individual cell divides into two daughter cells. During prophase (A), the DNA (deoxyribonucleic acid) in the form of chromatin condenses into chromosomes. During metaphase (C), the chromosomes move and align themselves in the middle of the cell. Next is anaphase (B), during which the chromosomes separate and migrate to opposite poles of the cell.
27. The articulation of the temporomandibular joint involves which two bones? A Temporal bone, mental protuberance B Sphenoid bone, coronoid process of the mandible C Temporal bone, mandibular condyles
Temporal bone and mandibular condyle (C) articulate to form part of the temporomandibular joint. Neither temporal bone and mental protuberance (A) nor sphenoid bone and the coronoid process of the mandible (B) articulate with each other.
92.Which developmental disturbance appears as a "tooth within a tooth" on radiologic examination? A Fusion B Tubercles C Gemination D Dens in dente
The abnormal invagination of the enamel organ into the dental papilla results in the developmental disturbance known as dens in dente (D) and appears as a "tooth within a tooth" on radiographic examination. In gemination (C), the single tooth germ tries unsuccessfully to divide into two tooth germs, resulting in a large single-rooted tooth with a common pulp cavity. With fusion (A), two adjacent tooth germs join together, leading to a large, falsely macrodontic tooth that can be verified with radiographic examination. Tubercles (B) are extra cusps that appear as small, round enamel extensions.
58.Each cell facilitates the exfoliation of a primary tooth EXCEPT one. Which one is the EXCEPTION? A Ameloblast B Osteoclast C Odontoclast D Cementoclast
The ameloblast (A) is the enamel-producing cell that does not facilitate exfoliation of teeth. The osteoclast (B) is necessary to resorb the alveolar bone anchoring the tooth. The odontoclast (C) is responsible for resorption of dentin. The cementoclast (D) is responsible for the resorption of cementum.
53.Which stage of tooth development occurs between the 11th and 12th weeks of prenatal development? A Bud B Cap C Bell D Initiation
The bell stage (C) occurs between weeks 11 and 12 of prenatal development. The initiation stage (D) occurs between weeks 6 and 7 of tooth development. The bud stage (A) occurs during week 8, whereas the cap stage (B) happens between weeks 9 and 10.
19. Which muscle originates from the alveolar process of the maxilla, the alveolar process of the mandible, and the pterygomandibular raphe? A Masseter B Risorius C Buccinator D Sternocleidomastoid
The buccinator (C) muscle is a thin, quadrilateral muscle originating from the three areas listed above. The masseter (A) originates from the zygomatic arch; the risorius (B) originates from a fascia superficial to the masseter muscle; and the sternocleidomastoid (D) originates from the clavicle.
59.The cervical loop is responsible for development of A dentin. B pulp. C enamel. D root.
The cervical loop is responsible for root (D) development. Dentin (A) is developed from odontoblasts. Pulp (B) develops from the inner cells of the dental papilla. The enamel of the crown of the tooth (C) is formed from ameloblasts.
29. Which major artery supplies the brain with blood and is palpated during emergency situations? A Aorta B Subclavian C Internal carotid D Common carotid
The common carotid artery (D) runs superiorly along the neck, lateral to the trachea and the larynx. When palpated against the larynx, the most reliable arterial pulse of the body can be monitored. The aorta (A) is a major artery, which gives rise to the common carotid artery and the subclavian artery (B) on the left side of the heart and the brachiocephalic artery on the right side of the heart. The internal carotid artery (C) supplies the anterior part of the brain and the eye and sends branches to the forehead and the nose. The aorta (A), the subclavian artery (B), and the internal carotid artery (C) cannot be reliably palpated in an emergency.
65.Eight bones compose the neurocranium, surrounding the brain. Fifteen bones compose the viscerocranium, or the bones of the face. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.
The correct answer is (C); the first statement is true, and the second statement is false. Eight bones compose the neurocranium: the frontal, the sphenoid, the ethmoid, and the occipital bones, which are single bones. The paired temporal and parietal bones also are part of the neurocranium. The second statement is false. There are 14 bones, not 15, that make up the viscerocranium, including the single mandible and the vomer. The paired nasal, lacrimal, zygomatic, inferior nasal conchae, palatine, and maxillae are the remaining bones composing the face. Choices A, B, and D do not accurately reflect the statements.
66.The sphenoid bone is composed of the A palatine process. B temporal fossa. C superior orbital fissure of the orbit. D base of skull anterior to occipital bone. E B, C, and D.
The correct answer is (E). The complex, three-dimensional sphenoid bone contains the temporal fossa (B), the superior orbital fissure (C), the base of the skull anterior to occipital bone (D), and the pterygoid processes. The palatine process (A) is part of the maxillae.
36. Many veins in the head and neck region lack valves. Valveless veins of the head and neck contribute to the severe and rapid spread of dental infections. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.
The correct choice is A; both statements are true. Most veins in the head and neck lack valves, with the exception of the external jugular vein. The lack of valves in the veins of the head and neck may contribute to severe and rapid spread of dental infections. Choices B, C, and D do not correctly reflect the statements.
14. The following characteristics describe muscle tissue EXCEPT one. Which one is the EXCEPTION? A Each muscle has two ends. B Muscle cells are called sarcomeres. C Muscles are categorized according to their role in movement. D The muscle origin is attached to the least movable part. E The muscle insertion is attached to the most movable part.
The correct choice is B. Muscle cells are called myocytes, whereas sarcomeres are the unit of contraction of the myofibrils of the muscle cell. Muscles have two ends (A) and are categorized according to their role in movement (C). The origin of each muscle is defined by its least movable attachment (D). In addition, the insertion is attached to the most movable part (E).
70.The abducens (VI), trochlear (IV), and oculomotor (III) nerves all provide innervation to the muscles of the eye. These nerves provide sensory innervation. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.
The correct choice is C. The first statement is true, and the second statement is false. The abducens, trochlear, and oculomotor nerves supply motor innervation to the muscle of the eye. Choices A, B, and D do not correctly reflect the statements.
86.During facial development, the two structures forming the major facial structures are the frontonasal process and the pharyngeal (branchial) arch I. This process begins during week 6 in utero. A Both statements are true. B Both statements are false. C The first statement is true, and the second statement is false. D The first statement is false, and the second statement is true.
The correct choice is C. The first statement is true. The frontonasal process will form the forehead and the middle third of the face, including the nose, the philtrum, maxillary incisors, and the premaxillary area or the primary palate. The first pharyngeal (branchial) arch I forms the mandibular and maxillary processes, which will form the mandible, most of the maxillae, and palatine bones. The zygomatic bones of the cheek are also formed from these processes. The second statement is false. This process begins during week 3 in embryologic development. By week 6, the major facial structures have formed and are developing in complexity. Choices A, B, and D do not accurately reflect the statements.
91.The face and its related tissues begin to form during week 6 of prenatal development, within the fetal period. Facial development is completed by week 12. A Both statements are true. B Both statements are false. C The first statement is true and the second statement is false. D The first statement is false, and the second statement is true.
The correct choice is D. The first statement is false. The face and its related tissues begin to form at the beginning of week 4 in the embryonic period, not during week 6 in the fetal period. However, the second statement is true. Facial development starts during weeks 3 and 4 and is completed in the twelfth week. Choices A, B, and C do not correctly reflect the statements.
68.The functions of the lymphatic system include all EXCEPT one. Which one is the EXCEPTION? A Filter fluids B Fight infection C Produce lymphocytes D Produce thrombocytes E Return plasma to venous bloodstream
The correct choice is D; thrombocytes are produced in bone marrow and not in the lymphatic system. The lymphatic system filters fluids (A), fights infection (B), produces lymphocytes (C), and returns plasma to the venous bloodstream (E).
98.Which statement is correct? (Select all that apply.) A Maxillary second premolars are bifurcated with a buccal and palatal root. B Mandibular molars are bifurcated with a mesial and distal root. C Maxillary molars are trifurcated with a mesiobuccal, distobuccal, and palatal root. D Maxillary first premolars are bifurcated with a buccal and palatal root.
The correct choices are B, C, and D. Mandibular molars have a bifurcated root: mesial and distal (B). Maxillary molars have trifurcated roots: mesiobuccal, distobuccal, and palatal (C). Maxillary first premolars may have a bifurcated root: buccal and palatal (D). Maxillary second premolars are rarely bifurcated (A).
95.Which acronym defines the correct sequence of words used to describe a tooth? A D-T-A-Q B D-A-C-T C C-A-D-Q D D-A-Q-T
The correct sequence of words used to describe a tooth is based on the D- A-Q-T system (D), with D for dentition A for arch Q for quadrant T for tooth type. For example, a dental professional may refer to a permanent (D) mandibular (A) left (Q) premolar (T). Acronyms in choices A, B, and C are incorrectly sequenced.
17. The corrugator supercilii is a muscle of facial expression in which region? A Eye B Nose C Mouth D Scalp
The corrugator supercilii is a muscle of facial expression located just superior to the eye (A) and deep to the superior portion of the orbicularis oculi muscle. The nose (B), mouth (C), and scalp (D) are not moved by the corrugator supercilii muscle.
64.The cusp of Carabelli is found on which permanent molars? A #3, #14 B #2, #15 C #19, #30 D #18, #31
The cusp of Carabelli is found on the lingual surface of maxillary first molars, which includes #3 and #14 (A). Teeth #2 and #15 (B) are maxillary second molars; #19 and #30 (C) are mandibular first molars; and #18 and #31 (D) are mandibular second molars.
47.Each of the following is a component of the tooth germ EXCEPT one. Which one is the EXCEPTION? A Enamel organ B Dental sac C Dental lamina D Dental papilla E Dental follicle
The dental lamina (C) is not part of the tooth germ, although the proliferation of ectodermal cells into specific sites is the first stage of odontogenesis. This thickened sheet of epithelium will give way to become the enamel organ. The three components that make up the tooth germ are the enamel organ (A), the dental sac (B), and the dental papilla (D). DENTAL FOLLICLE (E) is another term for dental sac.
63.The cells responsible for the development of the periodontal ligament come from the A dental sac. B dental papilla. C enamel organ. D successional lamellae.
The dental sac or follicle (A) consists of ectomesenchyme that surrounds the enamel organ and will produce not only the periodontal ligament but also cementum and alveolar bone. The dental papilla (B) has inner cells that will produce the pulp and outer cells that will produce dentin. The enamel organ (C) will produce enamel. The successional lamellae (D) comprise the epithelial tissue that will give rise to succedaneous teeth.
56.Which period of prenatal development occurs during months 3 to 9? A Fetal B Embryonic C Preimplantation D A only E Both A and B
The final period of prenatal development is the fetal period (A), which spans months 3 to 9 or delivery. After fertilization, the zygote travels along until it implants itself into the uterus. This period is known as the PREIMPLANTATION PERIOD (C), which occurs during week 1. The embryonic period (B) follows during weeks 2 through 8. Choices D and E do not correctly address the statement.
24. Which of the following is NOT innervated by the middle superior alveolar nerve? A Tooth #4 B Tooth #12 C Distobuccal root of tooth #2 D Mesiobuccal root of tooth #14
The distobuccal root of the maxillary second molar, tooth #2 (C), is innervated by the posterosuperior alveolar nerve, not the middle superior alveolar nerve. The middle superior alveolar nerve innervates maxillary premolars, teeth #4 and #5 (A) and, #12 and #13 (B), and the mesiobuccal root of maxillary first molars, teeth #3 and #14 (D).
71.Match each germ layer listed to the structure it forms in the developing embryo. Germ Layer Structure Formed in Embryo 1. Endoderm A. Gastrointestinal tract, epithelium, and associated glands 2. Mesoderm B. Nervous system, epidermis, sensory epithelium of the eye, ear, and nose tooth enamel and oral epithelium 3. Ectoderm C. Muscles, bone, cartilage, blood, dentin, pulp, cementum, and periodontal ligament
The endoderm (1) forms the gastrointestinal tract, epithelium, and associated glands (A). The mesoderm (2) forms muscles, bone, cartilage, blood, dentin, pulp, cementum, and periodontal ligament (C). The ectoderm (3) forms the nervous system, epidermis, sensory epithelium of the eye, ear, and nose; the tooth enamel; and the oral epithelium (B).
31. The facial artery is a direct branch of which main artery? A Subclavian B Internal carotid C External carotid D Brachiocephalic
The facial artery is the final anterior branch from the external carotid artery (C), not the subclavian artery (A), the internal carotid artery (B), or the brachiocephalic artery (D).
62.Which is the most common cell found in the lamina propria of the oral mucosa? A Epiblast B Odontoblast C Osteoblast D Osteoclast E Fibroblast
The fibroblast (E) is the most common cell found in the lamina propria of the oral mucosa. Epiblast (A) layers are high-columnar cells of the bilaminar embryonic disk. The odontoblast (B) is the cell that will produce dentin. The osteoblast (C) is a bone-forming cell, and the osteoclast (D) is a bone-resorbing cell.
12. Which plane of dissection divides the body into anterior and posterior portions? A Frontal B Sagittal C Horizontal D Median
The frontal (A) plane divides the body into anterior and posterior portions. The sagittal plane (B) divides the body in an anteroposterior direction. The horizontal plane (C) separates the body into superior and inferior portions, and the median plane (D) divides the body into equal right and left halves.
77.How many teeth are present in an individual with a full deciduous dentition? A 20 B 24 C 28 D 32
The full deciduous dentition contains 20 teeth (A). The full permanent dentition contains 32 teeth (D). Neither 24 (B) nor 28 (C) represents a full count of teeth at any stage.
38. Which muscle, upon contraction, protrudes the tongue? A Genioglossus B Hyloglossus C Styloglossus
The genioglossus muscle (A) protrudes the tongue upon contraction. The hyloglossus muscle (B) depresses the tongue when it contracts. Upon contraction, the styloglossus muscle (C) retracts the tongue.
37. Each of the following is an afferent cranial nerve EXCEPT one. Which one is the EXCEPTION? A Optic B Vagus C Olfactory D Hypoglossal
The hypoglossal nerve (D) is an efferent (motor) cranial nerve for both intrinsic and extrinsic muscles of the tongue. The optic nerve (A), the vagus nerve (B), and the olfactory nerve (C) are afferent, or sensory, nerves.
20. Which part of the brain regulates homeostasis? A Medulla B Thalamus C Cerebellum D Hypothalamus
The hypothalamus (D) regulates homeostasis in the body. The medulla (A) is part of the brain stem and is involved in regulating the components of the autonomic nervous system. The thalamus (B) plays a major role in relaying nerve impulses. The cerebellum (C) is responsible for the coordination of voluntary movements and for maintaining posture and balance.
34. Veins of teeth have alveolar branches and dental branches. Which branch type would drain the pulp tissue of teeth through the apical foramen? A Alveolar branches B Dental branches C Both A and B D Neither A nor B
The incisive artery branches off the inferior alveolar artery, remaining within the mandibular canal to divide into dental and alveolar branches. The dental branches (B) of the pulp drain the mandibular anterior teeth by way of each tooth's apical foramen. The alveolar branches (A) of the periodontium drain the mandibular anterior teeth, including the gingiva. Choices C and D do not correctly address the statement.
10.All of the following are foramina in the sphenoid bone EXCEPT the A incisive foramen. B superior orbital fissure. C foramen ovale. D foramen rotundum.
The incisive foramen (A) is an opening to the incisive canal in the palatine process of the maxilla. The superior orbital fissure (B), foramen ovale (C), and foramen rotundum (D) are all located in the sphenoid bone and are exit points for cranial nerve V.
28. Which artery supplies the mandibular teeth and surrounding tissues with blood? A Facial B Lingual C Inferior alveolar D Pterygoid plexus
The inferior alveolar artery (C) is a branch of the maxillary artery and supplies the mandibular teeth, the floor of the mouth, and the mental region with blood. The facial artery (A) is also known as the external maxillary artery and extends to the mid-face region to supply the oral, buccal, zygomatic, nasal, infraorbital, and orbital regions. The lingual artery (B) is an anterior branch from the external carotid artery and supplies the tissue superior to hyoid bone, including the suprahyoid muscles and the floor of the mouth. The pterygoid plexus (D) supplies the deep facial areas and the posterosuperior alveolar vein and the inferior alveolar vein.
9. The infraorbital foramen is located in which bone? A Frontal B Maxilla C Zygomatic D Sphenoid
The infraorbital foramen passes through the maxilla (B), not the frontal (A), zygomatic (C), or sphenoid (D) bones.
50.The inner cells of the dental papilla will develop into which structure? A Cementum B Dentin C Pulp D Enamel
The inner cells of the dental papilla develop into dental pulp (C). Cementum (A) is produced by cementocytes that come from the dental sac. Dentin (B) is produced by the outer cells of the dental papilla. Enamel (D) is produced by ameloblast cells that come from the enamel organ.
30. Which artery is the source of the ophthalmic artery, has NO branches, and is located deep to the sternocleidomastoid muscle? A Aorta B Subclavian C External carotid D Internal carotid
The internal carotid artery (D) is a branchless division of the common carotid artery, which is covered by the sternocleidomastoid muscle, and supplies blood to the ophthalmic artery. The aorta (A), a major artery that is a portion of the heart itself gives rise to the common carotid artery and the subclavian artery (B) on the left side of the heart and the brachiocephalic artery on the right side of the heart. The external carotid artery (C) travels superiorly to the internal carotid artery and has four sets of branches.
35. Which vein has NO valves, drains most of the head and neck region, and does NOT drain any of the dentition? A Internal jugular B External jugular C Internal maxillary D Inferior alveolar
The internal jugular vein (A) drains most of the head and the neck, except the dentition. The external jugular vein (B) is the only vein the head and neck with valves. The internal maxillary vein (C) drains the pterygoid plexus, whereas the inferior alveolar vein (D) drains the mandibular teeth and the periodontium.
72.For each of the developing branchial arches listed, select the most appropriate anatomic structure that it gives rise to. Developing Branchial ArchResulting Structure 1. Mandibular arch (branchial I) A. Muscles of facial expression, cranial nerve VII 2. Hyoid arch (branchial II) B. Tongue, cranial nerve IX 3. Branchial arch III C. Muscles of throat, inferior hyoid cartilage, cranial nerve X 4. Branchial arch IV D. Mandible, muscles of mastication, cranial nerve V
The mandibular arch (1) gives rise to the mandible, muscles of mastication, and cranial nerve V (D). The hyoid arch (2) gives rise to the muscles of facial expression and cranial nerve VII (A). Branchial arch III (3) gives rise to the tongue and cranial nerve IX (B). Branchial arch IV (4) gives rise to the muscles of the throat, the inferior hyoid cartilage, and cranial nerve X (C).
21. Which branch of the trigeminal nerve contains both sensory and motor components? A Ophthalmic V1 B Maxillary V2 C Mandibular V3
The mandibular or third division of the fifth cranial nerve V3 (C), or the trigeminal nerve, has both afferent or sensory and efferent or motor components. The afferent component provides sensation to the teeth and tissues of the mandible and the anterior two thirds of the tongue. The efferent component innervates the muscles of mastication, tensor tympani, and tensor veli palatini. The ophthalmic V1 (A), or the first division of the trigeminal nerve, provides sensation to the conjunctivae, cornea, eyeball, orbit, forehead, ethmoid and frontal sinuses, and part of the dura mater. The second branch of the trigeminal nerve, maxillary V2 (B), carries sensory information for the maxillae and overlying skin, maxillary sinuses, nasal cavity, palate, nasopharynx, and part of the dura mater.
67.Anatomically, the inferior alveolar artery supplies which structure? A Soft floor of mouth B Tongue muscles C Sublingual gland D Mandibular teeth
The mandibular teeth (D) and the bone of the mandible are supplied by the inferior alveolar artery. The lingual artery supplies the floor of the mouth (A), and its branches supply the tongue (B). The sublingual gland (C) is supplied by the sublingual and submental arteries.
1. Which paired muscle covers most of the lateral aspect of the ramus of the mandible? A Temporalis B Masseter C Lateral pterygoid D Medial pterygoid
The masseter (B) muscle is located on the lateral aspect of the ramus of the mandible. The temporalis (A) muscle is a large, fan-shaped muscle attached to the coronoid process of the mandible. The lateral pterygoid(C) has two heads and lies superiorly to the medial pterygoid. The medial pterygoid (D) inserts on the medial surface of the mandibular ramus. All these muscles are muscles of mastication.
89.Each is an anterior branch of the external carotid artery EXCEPT one. Which one is the EXCEPTION? A Occipital B Superior thyroid C Facial D Lingual
The occipital artery (A) is a posterior branch of the external carotid artery. The external carotid artery has four sets of branches, grouped according to location in relation to the main artery: (1) anterior, (2) medial, (3) posterior, and (4) terminal. The superior thyroid (B), facial (C), and lingual (D) arteries are all anterior branches of the external carotid artery.
88.Which muscle involved in facial expression does not have a bony attachment, shapes and controls the size of the mouth opening, and helps create lip positions and movements during speech? A Risorius B Zygomaticus major C Orbicularis oris D Levator anguli oris
The orbicularis oris muscle (C) shapes and controls the size of the mouth opening and is important in the creation of lip positions and movements during speech. The risorius muscle (A) stretches the lips laterally, retracting the labial commissure and widening the mouth to produce a grimace. The zygomaticus major muscle (B) elevates the labial commissure of the upper lip and pulls it laterally, thus helping create to a smile. The levator anguli oris muscle (D) elevates the labial commissure, as when a person smiles.
33. The facial vein drains each region of the head and neck EXCEPT one. Which one is the EXCEPTION? A Orbital region B Upper lip area C Lower lip area D Submental region
The orbital region (A) is drained by the cavernous sinus and the pterygoid plexus, not the facial vein. The facial vein drains the upper lip (B), the lower lip (C), and the submental region (D).
45. Each of the following is a period of prenatal development EXCEPT one. Which one is the EXCEPTION? A Fetal B Ovulation C Embryonic D Preimplantation
The ovulation period (B) occurs during a woman's menstrual cycle with the release of an ovum. The unfertilized egg is not part of prenatal development. The three distinct periods of prenatal development are the preimplantation period (D), occurring during the first week after fertilization; the embryonic period (C), occurring during the second to the eighth week; and the fetal period (A), which occurs from the third to the ninth month.
76.A hematoma that results from the administration of a posterior superior alveolar (PSA) nerve block is caused by bleeding from which arteries or veins? 1.Posterior superior alveolar artery 2.Pterygoid plexus of veins 3.Temporal artery 4.Facial artery 5.Maxillary vein 6.Posterior retromandibular vein A 1, 2, 5 B 2, 3, 4 C 3, 4, 6 D 1, 2, 4
The posterior superior alveolar artery (1), the pterygoid plexus of veins (2) and the facial artery (4) are located in the infratemporal fossa. This location may contain a high volume of blood if a hematoma occurs. The vessels listed in A, B, and C are not associated with the PSA nerve block.
8. Which injections technique would be used to achieve anesthesia of teeth #15 and #16? A Nasopalatine block B Anterosuperior alveolar block C Middle superior alveolar block D Posterosuperior alveolar block
The posterosuperior alveolar block (D) anesthetizes the mesiobuccal root of the first maxillary molar and the second and third maxillary molars. The nasopalatine block (A) anesthetizes the premaxillary area of the palate and the anterior maxillary teeth. The anterosuperior alveolar block (B) anesthetizes the gingiva and the anterior maxillary teeth. The middle superior alveolar block (C) anesthetizes the premolars and the mesiobuccal root of the first maxillary molar.
51.The earliest indication of a part or an organ during prenatal development is referred to as the A primordium. B stomodeum. C zygote. D nucleus.
The primordium (A) is the earliest indication of a part or an organ during prenatal development. The stomodeum (B) is also known as the primitive mouth and begins as just a slight depression but subsequently will give rise to the oral cavity. A zygote (C) is a fertilized egg, resulting from the union of a man's sperm and a woman's ovum. A nucleus (D) is a large organelle found in most cells, responsible for the regulation of all cellular function.
26. Which vein receives blood flow from the superficial temporal vein and the facial vein and drains into the external jugular vein? A Maxillary B Ophthalmic C Inferior alveolar D Retromandibular
The retromandibular (D) vein receives blood flow from the superficial temporal vein and the facial vein and drains into the external jugular vein. It is situated immediately posterior to the angle of the mandible. The maxillary vein (A) receives blood flow from the pterygoid plexus and drains into the retromandibular vein. The ophthalmic vein (B) drains the tissue of the orbit and proceeds into the facial vein. The inferior alveolar vein (C) forms from the merging of the dental, alveolar, and mental branches and drains into the pterygoid plexus.
6. Which spinal vertebrae fuse together to form a triangular mass? A Sacral B Lumbar C Cervical D Thoracic
The sacral (A) vertebrae of the spinal cord fuse together to form a triangular mass, called the sacrum. The lumbar (B) region comprises the five large vertebrae located between the thoracic and sacral regions. The cervical (C) region comprises the seven vertebrae located between the base of the neck and the thoracic region. The thoracic (D) region comprises the 12 vertebrae between the cervical and lumbar regions.
75.Which arteries are the terminal branches of the external carotid artery? A Superior thyroid, lingual B Facial, ascending pharyngeal C Posterior auricular and occipital D Maxillary, superficial temporal
There are approximately eight main branches of the external carotid artery. The terminal branches are maxillary and superficial temporal branches (D) given off deep to the neck of the condyle. The superior thyroid and lingual (A) branches and the facial and ascending pharyngeal (B) branches are given off in the carotid triangle. The posterior auricular and occipital (C) arteries are posterior arteries given off below maxillary and superficial temporal arteries.
40.Cervical lymph nodes run along which muscle? A Trapezius B Buccinator C Epicranial D Sternocleidomastoid
The sternocleidomastoid muscle (D) is a landmark of the neck during the extraoral examination to define locations of superficial and deep cervical lymph nodes. Cervical lymph nodes do not lie adjacent to the trapezius (A), buccinator (B), or epicranial (C) muscles.
39.Each of the following is a suprahyoid muscle EXCEPT one. Which one is the EXCEPTION? A Mylohyoid B Geniohyoid C Stylohyoid D Sternohyoid
The sternohyoid muscle (D) is an infrahyoid muscle. The mylohyoid (A), geniohyoid muscle (B), and stylohyoid (C) muscles are all suprahyoid muscles.
42.For each numbered structure, select the most closely linked primary nodes that drain those structures from the list provided.Anatomic StructureLphNiode Drainage 1. Sublingual salivary gland A. Deep parotid 2. Parotid salivary gland B Submandibular 3. Base of tongue C. Superior deep cervical 4. Paranasal sinus D. Submental 5. Low er lip E. Retropharyngeal
The sublingual salivary gland (1) is drained by the submandibular lymph node (B). The parotid salivary gland (2) is drained by the superior deep cervical lymph node (C). The base of the tongue (3) is drained by the retropharyngeal lymph node (E). The paranasal sinus (4) is drained by the deep parotid lymph node (A). The lower lip (5) is drained by the submental lymph node (D).
15. Which lymph nodes drain both sides of the chin, the lower lip, the floor of mouth, the apex of tongue, and the mandibular incisors? A Facial B Submental C Submandibular D Retropharyngeal
The submental (B) lymph nodes drain both sides of the chin, the lower lip, the floor of mouth, the apex of tongue, and the mandibular incisors. The facial lymph nodes (A) are superficial nodes located along the length of the facial vein and are further categorized into four subgroups that drain the areas they are named for: malar, nasolabial, buccal, and mandibular. The submandibular nodes (C) drain the cheeks, the upper lip, the body of the tongue, the anterior hard palate, and all teeth except the mandibular incisors and the maxillary third molars. The retropharyngeal lymph nodes (D) drain the pharynx, the palate, the paranasal sinuses, and the nasal cavity.
4. What is the purpose of the synovial membrane in a synovial joint? A Secrete fluid into the joint cavity B Surround the joint like a fibrous sleeve C Innervate the muscles that move the joint D Convey a sense of position and movement
The synovial membrane secretes synovial fluid (A), which lubricates the synovial joint. The capsular ligament surrounds the joint like a fibrous sleeve (B). The sensory nerve endings innervate the muscles that move the joint (C). Proprioceptive nerve endings convey a sense of position and movement (D).
74.The temporomandibular joint (TMJ) is capable of which two types of movement? A Rotation, gliding B Hinge, translation C Pivot, ball and socket D Ball and socket, saddle
The temporomandibular joint (TMJ) rotates and glides (A). Rotational movement occurs between the disk and the mandibular condyle in the lower synovial cavity. As the jaw opens further, an anterior gliding movement also occurs along the posterior slope of the articular eminence. Movements B, C, and D are not associated with the TMJ.
87.Each is a paranasal sinus EXCEPT one. Which one is the EXCEPTION? A Frontal B Mandibular C Maxillary D Sphenoidal E Ethmoidal
There is no structure called the mandibular sinus (B). Paranasal sinuses include the frontal (A), maxillary (C), sphenoidal (D), and ethmoidal (E) sinuses.
18. Which muscle elevates the mandible? A Risorius B Buccinator C Medial pterygoid D Lateral pterygoid
Upon contraction, the medial pterygoid (C) elevates the mandible. The risorius (A) stretches the lips by pulling each labial commissure laterally. The buccinator (B) compresses the cheeks during chewing by retracting the labial commissure. The lateral pterygoid (D) depresses, protrudes, and deviates the mandible laterally.
41.For each numbered muscle, select the most closely linked facial expression from the list provided.Muscles of Facial ExpressionFacial Expression upon Contraction of Muscle 1. Mentalis A. Frow ning 2. Risorius B. Raising chin and protruding low er lip 3. Corrugator supercilii C. Chew ing 4. Levator anguli oris D. Stretching lips 5. Buccinator E. Smiling
When the mentalis muscle (1) contracts, the chin is raised and the lower lip protrudes (B). When the risorius muscle (2) contracts, the lips are stretched (D). When the corrugator supercilii (3) contracts, this action produces a frown (A). When the levator anguli oris (4) contracts, this action produces a smile (E). When the buccinator (5) contracts, food is pushed onto the occlusal plane, facilitating the chewing of food (C).
11. Which muscle retracts the tongue? A Genioglossus B Hyloglossus C Styloglossus D Palatoglossus
When the styloglossus (C) muscle contracts, the tongue retracts. In contrast, the hyloglossus (B) will depress the tongue upon contraction, and the genioglossus (A) will protrude the tongue and depress portions. The palatoglossus (D) elevates the base of the tongue, and depresses the soft palate.