Anatomic Sciences 105-158 (muscle embryology heart).txt

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  1. The muscle that separates the anterior cervical triangle from the posterior triangle receives its motor innervation from which nerve?

    - CN V
    - CN VII
    - CN X
    - CN XI
    - CN XII
    • CN XI (accessory nerve)
    • The neck is divided into triangles. The muscle that separates the anterior cervical triangle and the posterior triangle is Sternocleidomastoid
    • Submental triangle
    • Digastric
    • Carotid
    • Muscular
  2. All of the longitudinal muscles of the pharynx
    are innervated by the vagus nerve via the pharyngeal plexus EXCEPT one. Which is the exception?

    - Stylopharyngeus
    - Palatopharyngeus
    - Salpingopharyngeus
    • Stylopharyngeus, is innervated by the glossopharyngeal nerve.
    • Stylopharyngeus and salpingopharyngeus elevate the pharynx during swallowing.
    • Musculature of the pharynx is comprised entirely of voluntary muscles.
    • The external circular layer includes superior, middle and inferior pharyngeal constrictors.
    • The Internal longitudinal layer includes the palatopharyngeus, stylopharyngeus and salpingopharyngeus.
  3. The functional unit of a skeletal muscle is contained specifically within which area?

    - Adjacent Z lines
    - H zones
    - I bands
    - A bands
    • Adjacent Z lines
    • - Each skeletal muscle fiber is surrounded by a membrane, the sarcolemma. In the muscle fibers cytoplasm (sarcoplasm) are tiny Myofibrils, arranged lengthwise. Each myofibril consists of two types of finer fibers (thick myosin and tin actin) filaments.
    • - During muscle contraction the sarcomere shortens when thick and thin filaments slide over eachother.

  4. Which muscle gets penetrated during an IAN injection, which, along with the masseter forms a sling around the mandible?

    - Temporalis
    - Medial pterygoid
    - Lateral Pterygoid
    - Buccinator
    - Posterior belly of the digastric
    • Medial pterygoid
    • The angle of the mandible rests in this sling formed by the medial pterygoid and masseter.
    • The medial pterygoid, masseter and temporalis (mainly anterior portion) elevate the mandible during chewing.
    • The superior origin of the Lateral pterygoid is from the infratemporal crest of the greater wing of the sphenoid bone (the inferior portion is from the lateral surface of the lateral pterygoid plate of the sphenoid bone). Both heads insert at the articular disc of TMJ and neck of condyle.
    • Mandible is protruded by action of BOTH LATERAL PTERYGOIDS, action of just one causes lateral deviation towards its opposite side.
    • All muscles of mastication are innervated by the mandibular division of the trigeminal nerve.
  5. The minutest manifestation of cleft palate would result in a bifid:

    - Soft palate
    - Hard palate
    - Uvula
    - Premaxilla
    - Alveolus
    • Uvula, is suspended from the soft palate. During swallowing the soft palate and uvula are drawn upward (closing the nasopharynx and preventing the entering of food). Innervated by the pharyngeal plexus of nerves.
    • Aperture which the mouth communicates with the pharynx is called the isthmus faucium
    • The glossopalatine arch (palatoglossus) runs on either side downward and forward to the side and base of the tongue. Formed by the projection of the palatoglossus muscle and its covering mucus membrane .
    • The phayngopalatine arch is larger and projects towards the middle. Is formed by the projection of the palatopharyngeus muscle (covered by a mucus membrane). This is where the palatine tonsil is lodged.
    • Palatal salivary glands are mainly mucus type and contribute to the oral fluid
    • Bifid uvula results from the failure of complete fusion of the palatine shelves. A unilaterally damaged pharyngeal plexus of nerves will cause the uvula to deviate to the opposite side.
  6. Which of the following muscles pulls the shoulder downward and forward?

    - Pectoralis major
    - Pectoralis minor
    - Teres major
    - Teres minor
    - Deltoid
    - Latissimus dorsi
    • Pectoralis minor: (medial pectoral nerve from brachial plexus) pulls shoulder down and forward.
    • Pectoralis major: (medial and lateral pectoral nerves from brachial plexus) adducts arm and rotates it medially.
    • Latissimus dorsi: (thoracodorsal nerve from brachial plexus) extends, adducts and medially rotates the arm
    • Deltoid: (axillary nerve C5 and C6) abducts upper limb at shoulder joint
    • Teres major: (Lower subscapular nerve, brachial plexus) medially rotates and adducts the arm
    • Teres minor: (branch of axillary nerve) Laterally rotates the arm and stabalizes the shoulder joint
  7. All muscles of mastication are innervated by the:

    - Ophthalmic division (V-1) of trigeminal nerve
    - Maxillary division (V-2) of trigeminal nerve
    - Mandibular division (V-3) of trigeminal nerve
    - Facial nerve (VII)
    • Mandibular division (V-3) of trigeminal nerve
    • They receive blood from the pterygoid portion of the maxillary artery.
    • Masseter, temporalis and medial pterygoid: close the mouth (elevating mandible)
    • Lateral pterygoid: opens, shifts and protrudes the mandible.
    • There is one motor nucleus, a special visceral efferent (SVE) nucleus associated with the trigeminal nerve. It innervates the muscles of the first brachial arch, which consists mostly of muscles of mastication but also includes tensor tympani and several other small muscles. The nucleus is located in the mid pons at the level of attachment of the trigeminal to the brain stem.
  8. Which muscle is responsible for the protraction of the tongue?

    - Hyoglossus
    - Styloglossus
    - Palatoglossus
    - Genioglossus
    • Genioglossus: protrudes apex of tongue through mouth (hypoglossal innervation)
    • Styloglossus: draws tongue upward and backward (hypoglossal innervation)
    • Hyoglossus: Depresses tongue (hypoglossal innervation)
    • Palatoglossus: Pulls root of tongue upward and backward while narrowing the oropharyngeal isthmus (pharyngeal plexus)
    • Paired extrinsic muscles originate on structures away from the tongue and insert onto it causing tongue movements during speaking, manipulating food, cleansing teeth and swallowing.
  9. Most of the muscles that act on the shoulder girdle and upper limb joints are supplied by branches of the brachial plexus. Which of the following is NOT?

    - Lavator scapulae 
    - Rhomboid major
    - Rhomboid minor
    - Trapezius
    - Serratus anterior
    - Pectoralis minor
    - Subclavius
    • Trapezius: suspends shoulder firdle from the skull and the vertebral column (accesory nerve CN XI)
    • Pectoralis minor: pulls shoulder down (brachial plexus)
    • Serratus anterior: pulls scapula forward and downward (brachial plexus)
    • Subclavius: depresses clavicle (brachial plexus)
    • Levator scapulae & Rhomboid major and minor: along with levator scapulae elevates medial border of scapula and pulls it medially (dorsal scapular nerve C5)
  10. Which muscle is responsible for keeping mucus membranes out of the plane of occlusion and the food out of the buccal vestibule?

    - Medial pterygoid
    - Lateral pterygoid
    - Buccinator
    - Masseter
    - Temporalis
    • Buccinator: originates from pterygomandibular ligament and raphe, in the maxilla from the alveolar process superiorly and horizontally between the anterior border of 1st and 3rd molars. In the mandible along the oblique line between 1st and 3rd molars.
    • It inserts at the orbicularis oris and skin at the angle of the mouth and is transversed by the parotid duct.
    • Damage to the facial nerve or its branches may cause weakness or paralysis of the facial nerves called bell's palsy
  11. The nerve that innervates temporalis also innervates which muscle?

    - Orbicularis oculi
    - Occipitofrontalis
    - posterior digastric
    - mylohyoid
    - auricularis
    • mylohyoid
    • Temporalis: Broad, fan shaped muscle of mastication that fills the temporal fossa superior to the zygomatic arch. Inserts at the coronoid process of the mandible.
    • ALL OTHER MUSCLES are muscles of facial expression and are innervated by the facial nerve (except for posterior digastric)
  12. All of the muscles of the soft palate participate in closing the nasopharynx during swallowing EXCEPT one.

    - Uvular muscle
    - Palatopharyngeus muscle
    - Tensor veli palati muscle
    - Palatoglossus muscle
    - Levator veli palati muscle
    • Palatoglossus muscle, does NOT close the nasopharynx during swallowing
    • Five paired skeletal muscles of the soft palate
    • Palatoglossus: pulls root of tongue upward and backward. Both contracting together cause the palatoglossal arches to approach midline and mouth is narrowed
    • Palatopharyngeus: pulls walls of pharynx upward, pull palatopharyngeal arches towards the midline
    • Levator veli palati: raises the soft palate
    • Tensor veli palati: tighten soft palate so it can be moved upward or downward as a tense sheet. This muscle curves around the pterygoid hamulus therefore is the hamulus weer to be fractured this muscles action would be affected..
    • Uvular: raises and shortens to help seal oral from nasal pharynx
    • All of these muscles are innervated by the pharyngeal plexus (of the vagus) EXCEPT the tensor veli palati (trigeminal)
  13. Which of the following travels with the esophagus through the esophageal opening in the diaphragm?

    - Aorta
    - Thoracic duct
    - Azygos vein
    - Vagus nerve
    - Right phrenic nerve
    • Vagus nerve, remember this because the vAGUS travels with the esophAGUS. The aorta, azygos vein and thoracic duct pass posterior to the diaphragm.
    • Diaphragm is a flat muscle, dome like that separates the chest and abdominal cavities involved in inspiration and expiration. Innervated by the phrenic nerve.
    • Diaphragm has 3 openings
    • Aortic opening: aorta, thoracic duct and azygos vein
    • Esophageal opening: esophagus and vagus nerves (left and right)
    • Caval opening: Inferior vena cava and right phrenic nerve.
  14. Which costal muscle can typically cross more than one intercostal space?

    - External intercostal muscles
    - Internal intercostal muscles
    - Innermost intercostals
    - Subcostal muscles
    - Transverse thoracic muscles
    • Subcostal muscles: they cross more than one intercostal space, raise ribs during inspiration
    • Transverse thoracic muscles and interal intercostal muscles: depress ribs during expiration.
    • Diaphragm is the main muscle of inspiration (innervated by the phrenic nerve). Intercostal muscles are mainly active during forced respiration (innervated by their corresponding intercostal nerves)
  15. Name the molecule that lies along the surface of F-actin and physically covers actin binding sites during the resting state.

    - G-actin
    - Tropomyosin
    - Troponin
    - Light meromyosin
    - Heavy meromyosin
    • Tropomyosin
    • The main contractile system of all muscular tissue is based on the interactions of two proteins actin and myosin. The system of these proteins is sometimes called actin-myosin contractile system.
    • Actin filaments: composed of actin (g-actin chains arranged into double helical chains called f-actin), tropomyosin (lie along the surface of F-actin strands) and troponin (small oval molecule attached to each tropomyosin)
    • Myosin filaments (myosin with 2 components): Light meromyosin (LMM) makes rod like backbone of myosin filaments. Heavy meromyosin (HMM) forms short lateral cross-bridges link to binding sites on acting during contraction. 
    • When a skeletal muscle contracts, a stimulus from the nervous system excites the muscle fibers starting a series of events that lead to interactions between the myosin (thick filaments) and actin (thin filaments) of the sarcomeres of the fibers.
  16. All of the muscles of the quadriceps group serve to extend or straighten the knee. Which one also flexes the thigh on the pelvis?

    - Rectus femoris
    - Vastus lateralis
    - Vastus intermedius
    - Vastus medius
    • Rectus femoris
    • The thigh has two distinct muscle compartments (anterior and posterior) separated by deep connective tissue (fascia)
    • Quadricep femoris has 4 parts (all innervated by the femoral nerve): Rectus femoris (straightens the knee and flexes the thigh on the pelvis). Vastus lateralis/intermedius/medialus (all extend or straighten the knee)
    • Leg is divided into the posterior (bicep femoris, semitendinosus, semimembranosus HAMSTRINGS), lateral and anterior compartments
    • All of the muscles in the posterior compartment of the calf region (both superficial and deep) are innervated by the tibial nerve
  17. Which of the following muscles of the anterior abdominal wall, when present, is innervated by the twelfth thoracic nerve?

    - External oblique
    - Internal oblique
    - Transversus
    - Rectus abdominis
    - Pyramidalis
    • Pyramidalis (when present tenses the linea alba and is innervated by the 12th thoracic nerve.
    • External and internal oblique: innervated by lower six thoracic nerves and support abdominal contents, parturation, flexing, vomiting, etc..
    • Transversus and rectus abdominis: compress abdominal contents and innervated by the lower six thoracic nerves.
  18. The middle pharyngeal constrictor muscle originates from the hyoid bone and the stylohyoid ligament and inserts along the pharyngeal raphe. Like the other pharyngeal constrictor  muscles, this muscle is innervated in part by which nerve?

    - Vagus
    - Spinal accessory
    - Hypoglossal
    - Trigeminal
    • Vagus (and also glossopharyngeal)
    • Constrictor muscles of the pharynx: (superior, middle and inferior) all constrict the pharynx and responsible for moving food down to the esophagus.
    • The stylopharyngeus, palatopharyngeus and salpingopharyngeus (longitudinal muscles of the pharynx) are involved in elevating the larynx.
  19. The connective tissue layer surrounding each individual muscle fiber is called the:

    - Perimysium
    - Epimysium
    - Endomysium
    • Endomysium
    • Endomysium: (connective tissue layer that surrounds each individual fiber)
    • Perimysium: surrounds fasciculi
    • Epimysium: surrounds entire skeletal muscle
    • The axon of a motor neuron is highly branched, and one motor neuron innervates numerous muscle fibers. When a motor neuron transmits an impulse, all of the fibers it innervates contract simultaneously.
  20. Peristalsis and other similar movements are produced by which type of muscle tissue?

    - Smooth muscle tissue
    - Striated muscle tissue
    - Skeletal muscle tissue
    - Cardiac muscle tissue
    • Smooth muscle tissue: is located throughout the body within tunica (walls) of hollow internal organs. Fibers are elongated and spindle-shaped with a single nucleus. The myofibrils lack transverse striations. Responsible for involuntary movements of internal organs.
    • Smooth muscle can be single unit (numerous gap junctions, fibers contract without nerve signals) or Multi-unit (lacks gap junctions, individual fibers automatically innervated)
    • Skeletal cells: are responsible for voluntary body movement. consist of elongated, cylindrical cells which are multi-nucleated and have distinct transverse striations.
  21. A surgeon performing a thyroidectomy accidentally transects a nerve. The patient then presents with hoarseness and difficulty breathing. There is a loss of sensation below the vocal folds and loss of motor innervation to all of the intrinsic muscles of the larynx EXCEPT the:

    - Thyroarytenoid
    - Posterior cricoarytenoid
    - Transverse arytenoid
    - Cricothyroid
    - Lateral cricoarytenoid
    • Cricothyroid
    • The nerve that was transected was the recurrent laryngeal nerve (damage to this nerve results in difficulty breathing and hoarseness.
  22. The axilla, or armpit, is a localized region of the body between the upper humerus and thorax. It provides a passageway for the large, important arteries, nerves, veins and lymphatics that ensure that the upper limb functions properly. The muscle that forms the bulk of the anterior axillary fold is the:

    - Latissimus dorsi
    - Pectoralis major
    - Subscapularis
    - Teres major
    - Teres minor
    • Pectoralis major
    • The axilla can be visualized to have a floor, an apex and 4 walls.
    • Anterior fold (pectoralis and minor muscles)
    • Posterior fold (latissumus dorsi and teres major)
    • Contents: axillary vessels, branches of the brachial plexus, both heads of biceps brachii and Croacobrachialis.
  23. A nerve lesion occurred severely impairing rotation and side to side movement of the head, which nerve was likely affected?

    - CN V
    - CN VII
    - CN X
    - CN XI
    - Ansa cervicalis
    • CN XI
    • Sternocleidomastoid (innervated by the spinal part of the accessory nerve C2 and 3)
  24. The anterior and posterior pillars of the fauces enclose which area of lymphoid tissue?

    - lingual tonsils
    - pharyngeal tonsils
    - palatine tonsils
    • Palatine tonsils
    • The fauces is a narrow passage from the mouth to the pharynx (between the soft palate and the tongue). On either side of the passage, two membranous fold called  pillars of the fauces, enclose the palatine tonsils.
    • The two arches formed by the anterior and posterior folds of mucous membrance are the glossopalatine and pharyngopalatine arches.
  25. Which of the following is NOT a characteristic of cardiac muscle?

    - Mononuclear
    - Syncytium
    - Intercalated discs
    - Gap junctions
    - Desmosomes
    • Syncytium, is a mass of cytoplasm containing numerous nuclei and cellular organelles. Skeletal muscle is formed embryonically from numerous myoblasts that fuse together thus skeletal muscle posses this characteristic.
    • Like skeletal muscle fibes, cardiac fibers contain myofilaments and are striated with actin and myosin.
    • Cardiac muscle can contract without nerve stimulus. They respond to increased demand by increasing the size of the fiber called compensatory hypertrophy.
    • Skeletal and Cardiac muscle cannot mitotically divide, but certain smooth muscle fibers can under hormonal influences (pregnancy)
  26. Which of the following tongue muscles is NOT innervated by the hypoglossal nerve?

    - Genioglossus
    - Palatoglossus
    - Styloglossus
    - Hyoglossus
    - Longitudinal
    • Palatoglossus
    • Remember all muscles end in -glossus begin with their site of origin.
    • All of the muscles of the tongue, both extrinsic and intrinsic are innervated by the hypoglossal nerve (except for the palatoglossus which is innervated by the pharyngeal plexus)
    • Trigeminal nerve provides sensory input to the anterior 2/3rd of the tongue andthe glossopharyngeal to the posterior portion.
    • Lingual artery (branch of the external carotid) irrigates the tongue and the veins drain into the internal jugular vein.
  27. Posterior placement of an IAN block injection can cause transient facial paralysis by depositing within which gland?

    - sublingual
    - submandibular
    - parotid
    - von ebner glands
    • Parotid gland
    • If needle is placed well below the mandibular foramen, the medial pterygoid muscle will be penetrated.
  28. Which muscle of the upper arm primarily extends the forearm?

    - Biceps brachii
    - Coracobrachialis
    - Brachialis
    - Triceps brachii
    • Triceps brachii
    • At the elbow joint, the muscles for flexion include brachii and brachialis, while the main extensor muscle is the triceps
    • Triceps: innervated by the radial nerve
    • Biceps, Brachialis and Coracobrachialis: innervated by the Musculocutaneous nerve
    • The radial nerve is most commonly injured in mid-humeral shaft fracture because this nerve runs in the radial (spiral) groove of the humerous.
  29. Which muscle does NOT elevate the mandible during function?

    - Medial pterygoid
    - Lateral pterygoid
    - Temporalis
    - Masseter
    • Lateral pterygoid
    • Medial pterygoid: Superficial head arises from the tuberosity of the maxilla. The deep head arises from the medial surface of the lateral pterygoid plate
    • Lateral pterygoid: The upper head arises from the infratemporal surface of the greater wing of the sphenoid bone. The lower head arises from the lateral surface of the lateral pterygoid plate.
    • * All of the muscles of mastication are innervated by the trigeminal nerve V3 (mandibular division)
  30. A patient with a condylar fracture, attempts protrusion and the mandible markedly deviates to the left. Which muscle is unable to contract?

    - Left lateral pterygoid
    - right lateral pterygoid
    - Left medial pterygoid
    - right medial pterygoid
    • Left lateral pterygoid
    • When both lateral pterygoids contract together they achieve protrusion of the mandible.
    • * Condylar neck fractures can result in the displacement of injured condyle into the infratemporal fossa.
  31. A patient with loss of appetite, swollen, smooth and fiery red tongue. The smooth nature is caused by a lack of which papillae that are the most numerous and cover the anterior two-thirds of the tongue?

    - Foliate
    - Circumvallate
    - Fungiform
    - Filiform
    • Filiform
    • Filiform: most numerous (fill), shaped like "V", characterized by the absence of taste buds and increased keratinization. They serve to grip food.
    • Fungiform: Knob or mushroom shaped, found at the tip and the sides, innervated by the facial VII.
    • Circumvallate: Largest but the fewest in numbers. They are in an inverted form at the back of the tongue. Associated with the ducts of Von Ebner's glands. Innervated by the Glossopharyngeal IX
    • Foliate: found on lateral margins as 3 to 4 vertical folds. Taste buds innervated by both facial VII (anterior papillae) and glossopharyngeal IX (posterior papillae).
    • Taste by areas of the tongue: sweet on the tip, bitter on the back, sour along the sides salty on the tip and sides, umami the back and sides.
  32. Which type of muscle cell uniquely contains intercalated discs?

    - Skeletal muscle cel
    - Cardiac muscle cell
    - Smooth muscle cell
    • Cardiac muscle cell
    • Cardiac muscle cell: muscle fibers contain centrally placed nuclei as well as intercalated discs (contain demosomes and gap junctions), which represent junctions between cardiac cells.
    • Skeletal muscle fibers: bundles of long, cylindric, multinucleated cells with myofibrils that are responsible for striated appearance. They do contain transverse tubules T tubules and their sarcoplasmic reticulum is very well developed. Voluntary control with actin and myosin as the contract element.
    • Smooth muscle fibers: uninucleate, spindle shaped cells (fusiform). Smaller than skeltal, do NOT posses transverse tubules, sarcoplasmic reticulum poorly developed, not striated. Contraction is slow and involuntary.
  33. Skeletal muscle possesses a well developed sarcoplasmic reticulum. This along with T tubules and terminal cisternae function in the release and reuptake of which molecule?

    - Sodium
    - Phosphate
    - Calcium
    - Glucose
    • Calcium
    • Sarcoplasmic reticulum is a network of tubules and sacs in skeletal muscle. It is analogous to smooth endoplasmic reticulum in other cells (who's function is the synthesis of proteins and can be rough when ribosomes are present).
    • The sarcoplasm of each muscle fiber contains parallel, thread like structures called myofibrils, each is composed of smaller strands called myofilaments, who contain actin and myosin.
    • The number of muscle fibers does NOT increase, only the size of each fiber
  34. The tongue appears in embryos at approximately 4 weeks in the form of 2 lateral lingual swellings and one medial swelling, the so-called:

    - Foramen cecum
    - Sulcus terminalis
    - Tuberculum impar
    - Epiglottic swelling
    • - Tuberculum impar
    • - These lingual swellings along with the tuberculum impar originate from the first pharyngeal arch, when these grow and fuse they create the anterior 2/3 of the tongue.
    • - A Second median swelling (the copula) is formed by the mesoderm of the second, third and fourth arches, which forms the posterior 3rd of the tongue. These are separated by a v-shaped groove called terminal sulcus. The foramen cecum is the remnant of the proximal end of the thyroglossal duct.
    • - Bifid tongue is the lack of fusion of the distal tongue buds (lateral swellings)
    • - *Remember, the branchial (pharyngeal) arches are stacked bilateral swellings that appear inferior to the stomedeum during the 4th week of development. 5th branchial arches are absent in humans.
    • - Between 6 and 8 weeks, salivary glands begin to appear.
  35. The cartilage in the second branchial arch is called:

    - Meckel's cartilage
    - Reichert's cartilage
    - Thyroid cartilage
    - Cricoid cartilage
    • Reichert's cartilage
    • Each paired branchial arch has its own developing cartilage, nerve, vascular and muscular components. These are of neural crest origin. 
    • First arch cartilageMeckel's cartilage, closely related to the developing of the middle ear, becomes ossified to form the malleus and incus of the middle ear, sphenomandibular ligament and portions of the sphenoid. Most of this cartilage disappears as bony mandible forms by intramembranous ossification, only some of Meckel's cartilage makes a contribution to it.
    • Second arch cartilageReichert's cartilage, closely related to the developing of the middle ear.stylod process of the temporal bone, stylohyoid ligament, lesser cornu of the hyoid and upper half of the body of the hyoid.
    • Third arch cartilage: greater cornu of the hyoid and lower half of the body of the hyoid
    • Fourth arch cartilage: forms the cartilages of the larynx.
  36. During the fourth week of prenatal development, the upper lip is formed when each ____ fuses with each _____ as a result of the underlying growth of the mesenchyme.

    - Frontonasal process, lateral nasal process
    - Maxillary process, medial nasal process
    - Lateral nasal process, medial nasal process
    - Maxillary process, lateral nasal process
    • Maxillary process, medial nasal process
    • The maxillary processes contributes to the sides of the upper lip and the two medial nasal processes contribute to the middle of the upper lip and these two fuse to form the lip at 6 weeks of development.
    • Maxillary processes partially fuse to mandibular arch to form labial commisures.
    • After the formation of the stomodeum (primitive mouth), but within the 4th week, the mandibular process fuse. During the same 4th week the frontonasal prominence also forms along with the medial nasal processes (middle of the nose) and the lateral nasal processes (alae, or sides of the nose)
  37. During the fourth week of embryonic development, the first branchial arch divides to form:

    - The two medial nasal processes
    - The mandibular and maxillary process
    - The two lateral nasal processes
    - The lateral and medial nasal process
    • The mandibular and maxillary process also called the prominences
    • The branchial arches are six pairs of U shaped bars with a core mesenchyme formed by neural crest cells that migrate to the neck region. 
    • After formation of the stomodeum (primitive mouth) but still within the 4th week, two bulges of tissue appear inferior to the primitive mouth, the two large mandibular processes of the first brachial arch.
  38. Which pharyngeal pouch gives rise to the inferior parathyroid gland and the thymus gland?

    - First
    - Second
    - Third
    - Fourth
    • Third
    • Four well defined pairs of pharyngeal pouches develop as endodermal evaginations from the lateral walls lining the pharynx. 
    • First: formation of tympanic membrane, auditory tube, tympanic cavity, mandible, maxilla, Meckel's cartilage, sphenomandibular ligaments
    • Second: Palatine tonsils, Reichert's cartilage, styloid process, stylohyoid ligament, lesse cornu and upper part of hyoid
    • Third: Inferior parathyroid glands, thymus gland, greater cornu and lower part of hyoid
    • Fourth: Superior parathyroid and ultimobranchial body, laryngeal cartilage.
  39. The primitive mouth, or stomodeum, initially appears as a shallow depression in the embryonic surface _____ at the cephalic end before the fourth week of prenatal development.

    - Ectoderm
    - Endoderm
    - Mesoderm
    • Ectoderm
    • In the future the stomodeum will give rise to the oral cavity, which is lined by oral epithelium, derived from ectoderm as a result of embryonic folding.
  40. The primary palate or median palatal process is formed by the merging of the frontonasal process with which other processes?

    - Lateral nasal processes
    - Medial nasal processes
    - Maxillary processes
    - Mandibular processes
    • Medial nasal processes
    • The palate is formed from two separate embryonic structures, which are also the stages: the primary and secondary palate and is completed at 12 weeks of prenatal development.
    • Primary palate formation: around the 5th week, intermaxillary segment arises as a result of fusion of the two medial nasal processes and the frontonasal process within the embryo. The intermaxillary segment gives rise to the primary palate, will contain incisors.
    • Secondary palate formation: around the 6th week, the bilateral maxillary processes gives rise to two palatal shelves. These two palatal shelves elongate and move towards each other forming the secondary plate. Gives rise to the soft palate and uvula.
    • Completion of the palate: To complete the palate, the secondary palate meets the posterior portion of the primary palate and fuse together, forming the final hard and soft portions of the palate at 12 weeks.
  41. The facial nerve is developmentally derived from the:

    - First branchial arches
    - Second branchial arches
    - Third branchial arches
    - Fourth branchial arches
    • Second branchial arches
    • First arches (mandibular): trigeminal, muscles of mastication, tensor tympani, tensor veli palatine muscles, mylohyoid and anterior belly of digastric.
    • Second arches (hyoid): Facial nerve, stapedius muscle, muscles of facial expression, posterior belly of digastric and stylohyoid
    • Third arches: Glossopharyngeal nerve, stylopharyngeal nerve.
    • Fourth arches: superior laryngeal branch and recurrent laryngeal branch of vagus nerve, levator palatine muscles, paryngeal constrictors, intrinsic muscles of the larynx.
  42. The nasal cavities are formed from which embryonic structure?

    - Stomodeum
    - Frontonasal process
    - Intermaxillary segment
    - Nasal pits
    • Nasal pits
    • Image Upload
  43. The coronary sinus receives most of the venous blood from the heart and empties into the:

    - Right ventricle
    - Left ventricle
    - Right atrium
    - Left atricum
    • Right atrium
    • When viewed from the back the most obvious structure lying in the coronary sulcus is the coronary sinus. This sinus receives most of the venous blood from the heart and empties into the right atrium. Its tributaries are the small, middle and greater cardiac veins.
    • Great cardiac vein: opens to the left extremity of the coronary sinus. Receives blood from left atrium and both ventricles.
    • Small cardiac vein: Opens into the right extremity of the coronary sinus. Receives blood from the back of the right atrium and ventricle.
    • Middle cardiac vein: ends in the coronary sinus near its right extremity.
    • Oblique vein: ends in the coronary sinus near its left extremity.
    • anterior cardiac veins and smallest cardiac veins DO NOT end in the coronary sinus.
  44. Sympathetic stimulation will have which direct effect on the heart?

    - Decreased automaticity
    - AV block
    - Increased vagal response
    - Bradycardia
    - Increased stroke volume
    • Increased stroke volume
    • The strength and frequency of the heart beat are controlled by the autonomic nervous system.
    • The heart also has an internal nervous system made up of the SA (sinoatrial) Node the pacemaker of the heart, and the AV (atrioventricular) node (which initiates a signal conducted thorugh the ventricular myocardium by way of purkinje fibers)
    • The vagus provides parasympathetic control of the heart. The effect of the vagus nerve at the SA node is the opposite of the sympathetic nerves, it decreases the heart rate. Strong vagal stimulation may produce an AV block.
  45. When the SA node fails, or the SA node impulse is blocked, which structure must take over as the pacemaker for the heart?

    - Sinoatrial node
    - Atrioventricular bundle
    - Purkinje fibers
    - Atrioventricular node
    • Atrioventricular node (AV NODE, must take over)
    • The impulse to stimulate heartbeat goes in this order SA Node--AV Node-- AV bundle --- Purkinje fibers.
    • Lower than 60 BPM is known as bradycardia, higher than 100 BPM is known as tachycardia.
    • SA node is in the wall of the right atrium, near the entrance of the vena cava. The rate of the discharge of the SA node sets the rhythm of the entire heartbeat.
  46. The apex of the heart is located at the level of the:

    - Third left intercostal space
    - Fourth left intercostal space
    - Fifth left intercostal space
    - Sixth left intercostal space
    • Fifth left intercostal space, the apex of the heart is formed by the tip of the left ventricle at the fifth intercostal space.
    • Ventricles are larger and thicker walled than the atria. The right ventricle pumps blood into the lungs. The left ventricle is larger and thicker walled than the right and pumps blood all throughout the body.
    • * ventricles receive blood from the atria
    • The heart functions as a double pump, the right side receives deoxygenated blood from systemic circuit (via the sup. and inf. vena cavae as well as the coronary sinus). The blood then goes from the right atrium to the right ventricle via the AV valve. The right ventricle then pumps blood into the pulmonary circuit (via the pulmonary semilunar valve).
    • On the left side (left atrium) receives the OXYGENATED blood from the lungs by way of the pulmonary veins. This blood then flows through the left AV valve into the left ventricle where it passes through the aortic valve and enters the arch of the aorta.
  47. In the fetal heart, the ______ permits blood flow from the right atrium to the left atrium.

    - Fossa ovalis
    - foramen ovale
    - Foramen rotundum
    - Ductus ateriosus
    - Ductus venosus
    • Foramen ovale: in the fetal heart the foramen ovale permits blood to flow from the right atrium to the left atrium. Eventually the formen ovale becomes permanently closed with fibrous connective tissue and becomes the fossa ovalis (in lower part of atrial septum) in the adult.
    • The ligamentum arteriosum is a remnant of the ductus arteriosus in the fetus, which closes within 24 hours of birth, when it doesn't it is called patent ductus arteriosus.
  48. A viral infection in the muscular layer of the heart is caused by coxsackie B, causes fever, headache, chest pain, pink frothy sputum and inflammation in which layer?

    - Epicardium
    - Myocardium
    - Endocardium
    • Myocardium
    • Internal or endocardium: homologous with tunica intima of blood vessels. Lines the surface of the heart chambers.
    • Myocardium: Homologous with tunica media of blood vessels. Forms the bulk of the heart mass and consists predominately of cardiac muscle cells.
    • Pericardium: set of membranes around the heart. Divided into visceral, parietal and fibrous pericardium (from inside to out)
  49. The left atrium and the left ventricle receive their major arterial supply from which artery?

    - Anterior interventricular branch of the left coronary artery
    - Circumflex branch of the left coronary artery
    - Marginal branch of the right coronary artery
    - Posterior interventricular branch of the right coronary artery.
    • Circumflex branch of the left coronary artery
    • The anterior interventricular artery is the most often involved in coronary occlusions and is often the one bypassed in bypass cardiac surgery
    • There are four sets of valves that keep the blood flowing in the proper direction through the chambers of the heart.
    • Right and left atrioventricular valves: located between the atria and ventricles. The right side is the tricuspid and the left side is the bicuspid (mitral) valve.
    • Semilunar valves: the pulmonary valve is located in the proximal end of the pulmonary trunk. The aortic semilunar valve is located in the proximal end of the aorta.
  50. Which of the following does not empty directly into the right atrium?

    - Azygeous vein
    - Inferior vena cava
    - Superior vena cava
    - Coronary sinus.
    • Azygeous vein
    • The coronary sinus lies in the posterior part of the coronary sulcus (atrioventricular groove) and opens in the right atrium between the opening of the inferior vena cava.
    • Superior vena cava: returns the blood from the upper half of the body
    • Inferior vena cava: returns the blood from the lower half of the body.
    • Image Upload
  51. A stethoscope is placed  in the left fifth intercostal space, medial to the nipple line. Which valve is best heard over the apex of the heart?

    - Tricuspid valve
    - Mitral valve
    - Pulmonary valve
    - Aortic valve
    • Mitral valve (bicuspid valve)
    • During ventricular systole: the ventricles of the heart contract and the pulmonary and aortic valves open to allow blood to flow to the pulmonary and general circulatory system (while mitral and tricuspid valves remain closed).
    • During ventricular diastole, the aortic and pulmonary valves close, while the artrioventricular valves open to allow blood to pass from atria to ventricles.
    • Tricuspid valve is best heard over right half of the lower end of the body of the sternum
    • Pulmonary valve is best hear over second left intercostal space
    • Aortic valve is best heard over second right intercostal space.
  52. In the healthy heart, during diastole, the aortic valve:

    - Prevents reflux of blood into the right ventricle
    - Prevents reflux of blood into the right atrium
    - Prevents reflux of blood into the right atrium
    - Prevents reflux of blood into the left ventricle
    • Prevents reflux of blood into the left ventricle
    • There are no chordae tendineae or papillary muscles associated with semilunar valves ONLY in ventricles of the heart.
  53. The pectinate muscles are prominent ridges of the atrial myocardium located on the inner surfaces of much of the:

    - Right atrium
    - Right ventricle
    - Left atrium
    - Left ventricle
    • Right atrium
    • The crista terminalis represents the junction between the sinus venosus and the heart in the developing embryo, is a ridge that runs along the right atrial wall from the opening of the superior vena cava to the inferior vena cava.
    • The SA Node is located in the crista terminalis near the opening of the superior vena cava.
  54. In a cardiac tamponade caused by trauma, the pericardial sac fills up with fluid. The increased pressure on the heart prevents the pumping chambers from filling up properly and in turn causes inadequate pumping of blood. The pumping chambers of the heart are anatomically known as:

    - Vena cavae
    - Ventricles
    - Nodes
    - Atria
    • Ventricles
    • The pericardium is a tough double-walled fibrous membranous sac that surrounds the heart. Is divided parietal (outer) and visceral (inner wall of the sac) pericardium.
    • The left and right ventricles make up the diaphragmatic surface of the hear. This part rests on the fibrous part of the diaphragm.
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Anatomic Sciences 105-158 (muscle embryology heart).txt
2015-08-13 19:47:50
Anatomic Sciences 105 158

Anatomic Sciences 105-158
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