BIOD151 - Module 5 Summary, Complete Solution With pictures and diagrams For Your Module 5 Exams.

BIOD151 - Module 5 Summary, Complete Solution With pictures and diagrams For Your Module 5 Exams. Figure 5.1 Posterior view of the nervous system. The brain and spinal cord (central nervous system) connect to the peripheral nervous system. Examples of peripheral nerves are spinal nerves (cervical, thoracic, and lumbar), the upper trunk of the brachial plexus, and the radial nerve. (3) Divisions of the Spinalis thoracis, cervicis, capitis Spinalis Thoracis Origin: spinous processes of T11-L2 Action: extension / flexion of vertebral column Spinalis Cervicis Origin: Spinous processes of C7-T2 Action: extend and laterally flex spine Spinalis Capitis Origin: spinous processes of lower cervical and upper thoracic vertebrae Action: extends vertebral column Scalenes (anterior, middle, posterior) Origin: transverse processes of C2- C7 Insertion: first and second ribs Action: elevates ribs 1 & 2 Innervation: cervical spinal nerves Innervation refers to the nerve stimulation of a muscle Lumbar Plexus (L1-L4) plexus that includes the femoral nerve and obturator nerve - supplies abdominal wall, anterior thigh, and genitalia Sacral Plexus (L4-S4) plexus that supply lower limbs, sciatic nerve: lower limb Superior gluteal nerve Inferior gluteal nerve Sciatic nerve • Tibial nerve • Common fibular (peroneal) nerve (4) Plexuses cervical, brachial, lumbar, sacral Brachial Plexus (C5-T1) plexus that includes the axillary nerve, musculocutaneous nerve, radial nerve, median nerve, ulnar nerve - nerve supply to the upper extremities (spine, shoulder, arm, hand) Cervical Plexus (C1-C5) plexus that supplies neck and phrenic nerve to the diaphragm Accessory Nerve motor fibers to neck and upper back - CN XI Motor Actions messages from the CNS to a muscle Sensation / Sensory Input messages received by the CNS from the external environment (figure 5.1 and 5.2) Figure 5.2 Peripheral nerves carry the communication from the central nervous system (brain and spinal cord) to the muscle. Peripheral nerves also carry information from the environment to the central nervous system. Peripheral Nerves Interconnecting branches of spinal nerves Surrounded by connective tissue sheaths - carry signals from the CNS (brain and spinal cord) to a specific muscle destination in order to provide movement Muscle Communication Pathway Communication within the body to coordinate movement starts in the brain with a message that is sent through the spinal cord and eventually attaches to a muscle. Peripheral nerves carry the signal from the central nervous system (brain and spinal cord) to a specific muscle destination to provide movement. Messages from the central nervous system to a muscle are called motor actions. Nerves also carry information from the external environment to the central nervous system, called sensation or sensory input (see Figure 5.1 and Figure 5.2). Spinal nerves combine to form complex networks of peripheral nerves throughout the body. Muscle Fiber cell containing thousands of myofibrils Myofibrils cylindrical in shape and run the length of the muscle fiber. The light microscope shows that a __________________has light and dark bands called striations. It is these bands that cause skeletal muscle to appear striated. Striations of __________________ are formed by protein myofilaments within contractile units called sarcomeres (see Figure 5.38) Sarcomeres a structural unit of a myofibril in striated muscle, consisting of a dark band and the nearer half of each adjacent pale band. A __________contains two types of protein myofilaments (also referred to as filaments). The thick filaments are made up of a protein called myosin, and the thin filaments are made up of a protein called actin. As a muscle fiber contracts, the _______________within the myofibrils shorten. When a _________________shortens, the actin (thin) filaments slide past the myosin (thick) filaments and approach one another. The movement of actin filaments in relation to myosin filaments causes the muscle to shorten. Actin A globular protein that links into chains, two of which twist helically about each other, forming microfilaments in muscle and other contractile elements in cells. Myosin The contractile protein that makes up the thick filaments of muscle fibers Myofilaments The contractile proteins, actin and myosin, of muscle cells Z Lines connect parallel bands of thin filaments (actin) - outside of the sarcomere - when a muscle contraction occurs, these lines move closer together towards the center of the sarcomere (M line) M Line supporting proteins that hold the thick filaments (myosin) together in the H zone - middle of sarcomere I Band (light band) appears light when stained because it only contains thin filaments. A Band (dark band) contains thin and thick filaments; however, it stains darker because it contains the thick filaments Figure 5.38 View of a muscle fiber, to the microscopic view of a thick and thin filament. Note the heads on the myosin filaments that enable the work of the muscle contraction. Cross Bridges In the presence of calcium ions, portions of the myosin filaments called ___________- ___________ bend backward and attach to actin filaments. After attaching to the actin filament, the _____-____________bend forward and the actin filament is pulled along. The ___-________ attach and detach some fifty to 100 times as the thin filaments are pulled to the center of a sarcomere. ATP is needed on a cellular level for the myosin ____-________to pull the actin filaments. Muscle Contraction (on cellular level) The movement of the many actin filaments together is what produces a muscle contraction. Muscle contraction ceases when the nerve impulses no longer stimulate the muscle fiber. With the cessation of a muscle action potential, calcium ions are pumped back into the sarcoplasmic reticulum by active transport. Once the calcium ions return to the sarcoplasmic reticulum, relaxation of the muscle occurs. Sarcoplasm cytoplasm of a muscle cell - the presence of sodium ions causes an action potential to occur in the sarcolemma (cell membrane of a muscle fiber). The action potential causes calcium ions to be released from the sarcoplasmic reticulum Sarcolemma plasma membrane of a muscle fiber - the presence of sodium ions causes an action potential to occur in the sarcolemma (cell membrane of a muscle fiber). The action potential causes calcium ions to be released from the sarcoplasmic reticulum Acetycholine (ACh) (a special chemical called a neurotransmitter) is released from the motor nerve ending (Figure 5.40). _______________ binds to receptors on the muscle cell, opening sodium channels and allowing sodium to flow inside the sarcoplasm (cytoplasm of a muscle cell). The presence of sodium ions causes an action potential to occur in the sarcolemma (cell membrane of a muscle fiber). The action potential causes calcium ions to be released from the sarcoplasmic reticulum Neuromuscular Junction the junction between a nerve fiber and the muscle it supplies Figure 5.39 Histological view of a sarcomere (top) with diagram (below) with labeled components. Figure 5.40 The neuromuscular junction, step 1: The motor neuron (yellow) releases acetylcholine into the neuromuscular junction. Acetylcholine (red) binds with receptors on the muscle cell membrane (sarcolemma), opening sodium channels. Sodium (white) rushes in, creating an action potential, which reaches the sarcolemma and then the sarcoplasmic reticulum (blue). Figure 5.41 The neuromuscular junction, step 2: Once the action potential reaches the sarcoplasmic reticulum (dark blue), calcium ions (light blue) are released. The influx of calcium triggers the cross-bridge formations to and muscle contraction. Actin moves towards the center of the sarcomere. (3) Types of Muscle Tissue skeletal, cardiac, smooth Triceps Brachii Action: extends elbow, adducts humerus Innervation: radial nerve Bicep Brachii Actions flexes elbow, adducts hand (medial rotation) Innervation: Musculocutaneous Nerve Action Terms - Body Movement Flexion - closing of a joint, “bending” Extension - opening of a joint, “straightening” Antagonistic pair example: Flexor - biceps brachii Extensor - triceps brachii Abduction - movement away from midline Adduction - movement towards midline Antagonistic pair example: Abductor: TFL (of the hip) Adductor: adductor longus, adductor magnus Dorsiflexion - flexion superiorly occurring at the subtalar (ankle) joint (movement of the toes “up”) Plantarflexion - flexion inferiorly occurring at the subtalar (ankle) joint (movement of the toes “down”) Antagonistic pair example: Dorsiflexor: tibialis anterior Plantarflexor: gastrocnemius Radial Deviation - lateral movement of the wrist towards the radiusUlnar Deviation - medial movement of the wrist towards the ulna Antagonistic pair example: Radial Deviator: flexor carpi radialis Ulnar Deviator: extensor carpi ulnaris Pronation - rotation of the forearm so that the palm faces posteriorly (or) rotation of the ankle so the sole of the foot faces laterally Supination - rotation of the forearm so that the palm faces anteriorly (or) rotation of the ankle so the sole of the foot faces medially Antagonistic pair example: Pronator: (of forearm) pronator teres Supinator: (of forearm) biceps brachii Elevation – upward movement of a structure Depression – downward movement of a structure Antagonistic pair example: Elevator: levator scapulae Depressor: trapezius (lower fibers) Retraction - movement of a structure to be drawn in the posterior direction (drawn backward) Protraction - movement of a structure to be drawn in the anterior direction (drawn forward) Antagonistic pair example: Retractor: rhomboids, trapezius Protractor: serratus anterior Skeletal Muscles Under voluntary control - must have a blood and nervous supply to provide movement. These muscles are under conscious control, meaning that a person can consciously decide to use these muscles to complete an action - All of these muscles have an origin, insertion, and action - striated - make up over 40% of the body's weight, are attached to the skeleton by tendons, made of fibrous connective tissue - must work in antagonistic pairs because muscles are only able to pull in the direction of their fiber orientation. If one muscle of an antagonistic pair bends the joint and brings the limb toward the body (the flexor), the other one straightens the joint and extends the limb (the extensor) Smooth Muscle Under Involuntary control - muscle found inside many internal organs of the body - found within the internal organs of the body, such as the digestive tract and blood vessels - free of striations Cardiac Muscle Under Involuntary Control - muscle tissue found only in the heart - striated Antagonistic Pair When muscles contract, they become shorter. Muscles can only pull; they cannot push. Skeletal muscles must work in antagonistic pairs because muscles are only able to pull in the direction of their fiber orientation. If one muscle of an antagonistic pair bends the joint and brings the limb toward the body (the flexor), the other one straightens the joint and extends the limb (the extensor), as shown in the figure below. The following is a review of action terminology (see Module 1) with examples of antagonistic pairs found within the muscular system: Tendons are connective tissues that connect skeletal muscle to bone at each end (see Figure 5.3). These are flexible, can bend at the joints, and help cushion against sudden movement. Ligaments are connective tissue that connects bone to bone, helping to stabilize joints where bones meet Figure 5.3 Skeletal muscles attach to bones via tendons at points called the origin and insertion. The origin is the fixed point while the insertion is the place that is moved during a muscle contraction.