Generalities of Muscle PDF - 1st Year, 2024-2025

SUBJECT 1st Year | A.Y. 2024-2025 Lecture: Generalities of Muscle Prepared by: Tubat, Campos, De Jose, Valiente Lecturer: Farouk Jajurie Jr. MD, Date: September 13, 2024 MUSCLES TISSUES Branchiomeric Musculature...

SUBJECT 1st Year | A.Y. 2024-2025 Lecture: Generalities of Muscle Prepared by: Tubat, Campos, De Jose, Valiente Lecturer: Farouk Jajurie Jr. MD, Date: September 13, 2024 MUSCLES TISSUES Branchiomeric Musculature  All of the branchiomeric muscles that come from the first branchial arch are innervated by the trigeminal nerve. These muscles include all the muscles of mastication, the anterior belly of the digastric, the mylohyoid, tensor tympani and tensor veli palatini.  All of the branchiomeric muscles of the second branchial arch are innervated by the facial nerve. These muscles include the EMBRYONIC DEVELOPMENT OF THE MUSCLES muscles of facial expression, the posterior belly of the digastric, stylohyoid muscle and the stapedius muscle of the middle ear  There is only one muscle of third branchial arch, the stylopharyngeus. The stylopharyngeus is innervated by the glossopharyngeal nerve.  All the brachial muscles of the fourth and sixth arches are innervated by the vagus Branchial Arches nerve. These muscles include all the muscles SPECIFIC INSTRUCTIONAL OBJECTIVES: of the palate (exception of the tensor veli palatini which is innervated by the trigeminal Discuss what develops/arise from branchial arches nerve),all the muscles of the pharynx (except stylopharyngeus which is innervated by the glossopharyngeal nerve, and all the muscles of the larynx) MUSCLES DEVELOPING FROM SOMITE MYOTOME Epaxial Muscles Skeletal muscles which lie DORSAL to the vertebral column. In humans, this is only a small muscle group formed by the transversospinalis, longissimus and iliocastalis muscles. Also at the ribcage level the levatores costartum muscles Subject | Lecture no. 1 Ferviente 2028 SUBJECT 1st Year | A.Y. 2024-2025 Lecture: Generalities of Muscle Prepared by: Tubat, Campos, De Jose, Valiente Lecturer: Farouk Jajurie Jr. MD, Date: September 13, 2024 involved with rib elevation during respiration. 4. Stabilizes joint 5. Maintaining Posture HEAT GENERATION  Muscle contraction requires energy and produces heat as a byproduct of Hypaxial Muscles Skeletal muscles lying VENTRAL to the metabolism. vertebral column. These muscles contribute both body (trunk) and limb skeletal muscle. Hypaxial muscles include some vertebral muscle, the SHAPE AND CONTOUR diaphragm, the abdominal muscles, and all limb muscles. PARTS OF THE SKELETAL MUSCLES STABILIZING JOINT 1. ORIGIN - the stable attachment. More PROXIMAL part 2. INSERTION - the mobile attachment. More DISTAL part 3. BELLY - Fleshy part of the muscle FUNCTIONS OF MUSCLES 1. Movement 2. Heat Generation 3. Shape and Contour Maintaining Posture Subject | Lecture no. 2 Ferviente 2028 SUBJECT 1st Year | A.Y. 2024-2025 Lecture: Generalities of Muscle Prepared by: Tubat, Campos, De Jose, Valiente Lecturer: Farouk Jajurie Jr. MD, Date: September 13, 2024  Quadriceps femoris in extension of knee joint vs Biceps femoris SYNERGIST Complements the actions of the prime movers FIXATOR This is a muscle that contracts isometrically ROLES OF MUSCLES IN MOVEMENTS (increases muscle tone but produces no movement) to stabilize the origin of the prime mover so that it can act efficiently. Muscle Tone PRIME MOVER (AGONIST) Partial state of contraction of muscles while resting Refers to the chief muscle or a member of a chief group of muscle responsible for a particular movement Example:  Triceps in extension of the forearm  Biceps brachii in flexion of the elbow ANTAGONIST Any muscle that opposes the action of the prime mover Example:  Triceps brachii in extension of the forearm vs Biceps brachii Subject | Lecture no. 3 Ferviente 2028 SUBJECT 1st Year | A.Y. 2024-2025 Lecture: Generalities of Muscle Prepared by: Tubat, Campos, De Jose, Valiente Lecturer: Farouk Jajurie Jr. MD, Date: September 13, 2024 MOTOR UNIT Consists of a motor neuron in the anterior gray horn or column of the spinal cord and all the muscle fibers it supplies Importance of Nerve Supply to Muscles Loss of motor innervation induces rapid skeletal muscle fiber degeneration with the activation ofatrophy-related signaling and subsequent disassembly of the sarcomeres. This results in a loss of muscle function. Some of these changes can be observed within just a few hours after denervation. The basic system present throughout spinal cord anatomy is that 1. Dorsal roots carry afferent fibers 2. Ventral roots carry efferent fibers 3. Similarly, the ventral horn contains efferent cell bodies, and the dorsal root ganglion contains afferent cell bodies. Disuse Atrophy (Remember that the white matter contains myelin Disuse (physiologic) atrophy is caused by not and is therefore where you can find axons. The cell using your muscles enough. If you stop using your bodies will be located in the gray matter.) muscles, your body won't waste the energy it needs to take care of them. Instead, your body will start to break MNEMONIC - SAD DAVE your muscles down, which causes them to decrease Sensory = Afferent = Dorsal in size and strength. Dorsal = Afferent | Efferent = Ventral Innervation of Skeletal Muscle Every skeletal muscle is supplied by one or more nerves. The nerve trunk is a mixed nerve (60 % motor and 40 % sensory) which also contains sympathetic fibers Subject | Lecture no. 4 Ferviente 2028 SUBJECT 1st Year | A.Y. 2024-2025 Lecture: Generalities of Muscle Prepared by: Tubat, Campos, De Jose, Valiente Lecturer: Farouk Jajurie Jr. MD, Date: September 13, 2024 BASES OF NOMENCLATURE OF MUSCLES. Example: Action 1. Triangular = Deltoid The muscle is named for the movement they 2. Square = Quadratus produce 3. Diamond = Rhomboid major & Example: minor 1. Dilator Nares Direction of fibers 2. Pronator Teres The direction of the muscle fibers are used to 3. Flexor carpi radialis describe muscles. 4. Levator scapulae Example: 5. Supinator 1. Straight = rectus 6. Extensor indicis 2. At an angle = obliques Attachments/Structure 3. Horizontal = transverse It is named based on the muscle where it is Combination attached to The combination of two or more muscles can Example: influence their name. 1. SCM-from sternum and clavicle to mastoid Example: process 1. Flexor digitorum longus = long flexors of digits 2. Coracobrachialis-from coracoid process to arms 2. Latissimus dorsi = broadest muscle of the Depth back Depth can also influence the naming of the muscle EXTRINSIC MUSCLES Example: 1. Superficialis = Superficial Flexor Digitorum Superficialis 2. Profundus = Deep Flexor digitorum profundus Position The location or position of muscle to a particular bone often determines its name. Example: 1. Pectoralis = chest Pectoralis major & minor 2. Brachii = the arm biceps brachii 3. Dorsi = back latissimus dorsi 4. Femoris = thigh rectus femoris Number of heads or bellies Some muscle names indicate the number of muscles in a group Example: 1. Biceps = two origin 2. Triceps = three origin 3. Quadriceps = four origin Size Size can also influence the name of the muscle Example: 1. Major & Minor (In the buttocks) ➔ gluteus maximus (largest) ➔ gluteus medius (medium) ➔ gluteus minimus (smallest) Shape Names of some muscles can be reflected by INTRINSIC MUSCLES their shape Subject | Lecture no. 5 Ferviente 2028 SUBJECT 1st Year | A.Y. 2024-2025 Lecture: Generalities of Muscle Prepared by: Tubat, Campos, De Jose, Valiente Lecturer: Farouk Jajurie Jr. MD, Date: September 13, 2024 Subject | Lecture no. 6 Ferviente 2028