Anatomy Lecture Exam 2 Review PDF

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Anatomy Lecture Exam 2 Quizlets for each of the lectures in this unit: https://quizlet.com/tatumbrown2000/folders/anatomylecture-unit-2?x=1xqt&i=biuh4 Musculoskeletal System I ● Muscle movement + types of contractions ○ Skeletal muscles act in groups ■ Agonist-antagonist (opposing pairs) ● Agonist: the main muscle responsible for producing a specific movement of the body ● Antagonist: a muscle that opposes the action of the agonist muscle. As the Agonist muscle contracts, the antagonist progressively relaxes, producing a smooth movement ● You cannot have movement if you only have it in one direction, you have to be able to bring it back to the original position or control the movement ● Ex: flexor-extensor, abductor-adductor ○ Origin: the proximal end of a muscle that remains fixed during contraction ○ Insertion: the distal end of a muscle that is moveable ○ When muscles move, sarcomeres shorten and the muscle length (including the tendons) shortens ○ Muscles pull, never push ○ To produce a movement, a muscle must be attached to two bones and cross at least one joint ○ Always have a slight contraction at rest → tone ○ Types of contractions ■ Isometric contraction: sarcomeres shorten during increased tension, but muscle length doesn’t shorten ● e.g. Deltoid maintains steady contraction, holding arm in abducted position ■ Isotonic contraction: load is fixed by muscle length shortens/lengthens ● 2 forms of Isotonic Contraction ○ Concentric contraction: against gravity (raising hand up) ■ e.g. The Deltoid muscle shortens to raise the arm in abduction ○ Eccentric contraction: reduce the effect of gravity ■ Muscle relaxes; force generated becomes less than gravity; Gravity pulls limb down as muscle resistance decreases ■ e.g. The Deltoid muscle lengthens to lower the arm in adduction ○ MA: Isotonic Eccentric contractions produce the most muscle injury. Why?

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○ Neuromuscular junction ○ Is the chemical synapse formed by the contact between a motor neuron and a muscle fiber ○ A muscle contracts when the synapse releases neurotransmitter acetylcholine onto the motor end plate, which excites the muscle and causes it to contract ■

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In more detail: Nerve releases a neurotransmitter called acetylcholine into → Synaptic cleft → receptors on the junctional fold of sarcomeres → Acetylcholine goes down T-tubules → terminal cisternae→ calcium is released into sarcoplasmic reticulum → excites/polarizes muscle → myosin attaches/muscle contracts

○ Why are junctional folds important? ■ They greatly increase the surface area for the neurotransmitters to act Types of joints + examples ○ Fibrous joints/synarthroses: limited/no movement ■ Syndesmosis: joined by dense fibrous connective tissue ● Ex: interosseous ligaments (radius/ulna and tibia/fibula) ■ Sutures: bones unite ● Ex: skull bones in adults ● Synostosis is different ○ It is the fusion of bones and contains only bone while sutures contain fibrous tissue ○ Cartilaginous joints: slight movement ■ Synchondrosis: joined by hyaline cartilage ● Ex: epiphyseal plate, costochondral joints (in vertebrae) ■ Symphysis: joined by fibrocartilage ● Ex: symphysis pubis ○ Synovial joints/diarthroses: free movement Microscopic anatomy of synovial joints/articular cartilage ○ Articular cartilage

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Cartilage that cover the ends of bone Allows the surfaces of the bones to slide w less friction and absorb shock

Musculoskeletal System II: Upper Limbs ● Identify muscles that move shoulder girdle and what movements are involved: moved by clavicle and sternum ○ Posterior pectoral girdle ■ Trapezius: innervated by CN11 ● Wide set of attachments, actions mostly affect scapula ● Elevates, depresses, retracts and upwardly rotates the pectoral girdle ■ Levator scapulae ● Elevates scapula ■ Rhomboids ● Pull scapula toward midline and elevates it ○ Anterior pectoral girdle ■ Serratus anterior ● When contracted, it pulls scapula forward ● f7896Originates on ribs ■ Pectoralis minor ● Helps hold scapula tight to body wall by attaching to ribs ■ Subclavius ● Stabilizes scapula, right underneath it ● Describe muscles that move the arm at the shoulder and elbow and their innervation ○ Move the arm at the shoulder (anterior) ■ Pectoralis major muscle ● Actions: flex(pull muscle forward), adduct, rotate arm ● Innervated by pectoral nerves

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Move the arm at the shoulder (posterior) ■ Latissimus dorsi ● Actions: extend (pull arm back), adduct, rotate arm ● Innervated by thoracodorsal nerve

Move the arm at the elbow (anterior), originate from scapula or shoulder joint ■ Deltoid ● Innervated by axillary nerve ● Actions: Flex, extend, and abduct arm ■ Coracobrachialis ● Innervated by musculocutaneous nerve ● Actions: Flexes arm at shoulder ■ Biceps brachii ● Innervated by musculocutaneous nerve ● Actions: Flexes arm at shoulder; Flexes forearm at elbow, supination ○ Move the arm at the elbow (posterior) ■ Deltoid ● Innervated by axillary nerve ● Actions: Flex, extend, and abduct arm ■ Teres major ● Innervated by brachial plexus nerves ● Runs from scapula to arm ● Action: Adducts arm at shoulder ■ Triceps brachii ● Innervated by radial nerve ● Only muscle in posterior arm ● Action: Extends forearm at elbow Muscle compartments of the arm and forearm + their functions and innervations ○ Anterior compartment ■ Includes biceps brachialis, coracobrachialis, brachialis ■ Actions: flex at shoulder and elbow, adducts arm at shoulder, supinates hand ■ Innervated by musculocutaneous nerve ○ Posterior compartment ■ Includes triceps brachialis ○

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Actions: extend at shoulder/elbow ■ Innervated by radial nerve Know what rotator cuff muscles do and how they do it ○ Composed of 4 muscles ■ Teres minor ■ Infraspinatus ■

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Supraspinatus (Does not rotate the humerus): initiates abduction Subscapularis

All EXCEPT supraspinatus rotate the humerus Set of muscles that surround shoulder joint: stabilize joint, abduct and rotate arm at shoulder Hold proximal humerus in its place Innervation: posterior branches of brachial plexus Supraspinatus initiates ■

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Musculoskeletal System III: Lower Limbs ● Describe the muscles that move the thigh at the hip and what movements are involved ○ Gluteal region ■ Actions: abduct and extend thigh ■ Includes gluteus maximus, medius and minimus, tensor fascia lata ■ Innervated by gluteal nerves ○ Anterior thigh ■ Actions: flex thigh at hip ■ Includes ● iliacus and psoas major → innervated by lumbar plexus ● Sartorius → innervated by femoral nerve ● Rectus femoris → innervated by femoral nerve ■ Innervated by femoral nerve, lumbar plexus ○ Posterior thigh ■ Action: extends the thigh at the hip ■ Includes ● Biceps femoris ● Semitendinosus ● Semimembranosus ■ Innervated by the sciatic nerve ● What are the gluteal muscles and their functions? ○ Gluteus maximus: primary extensor of thigh ○ Gluteus medius: primary abductor of thigh ■ Use it to balance and walk ○ Gluteus minimus: abductor of thigh ● Muscle compartments of the thigh and leg + their functions and innervations

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Anterior compartment (flexors) ■ Iliopsoas ● Originates on vertebral column inside abdomen and inserts on anterior femur ● Action: Flexion of the femur at the hip ● Psoas major has ureter cross its anterior surface ● Ilacus originates of ilium ■ Sartorius ● Long thin muscle “Tailor's muscle” ● Originates on Ilium and inserts on Tibia ● Action: Flex at the hip ● Innervated: Femoral nerve ■ Rectus femoris ● Action: Also extends the leg at the knee ● Innervated: Femoral nerve ● Is a belly of the quadriceps femoris muscle ● Only muscle belly of the quadriceps that crosses the hip joint and acts on the joint ■ Quadriceps femoris ● Includes: rectus femoris, vastus lateralis, vastus medialis, vastus intermedius ○ Rectus femoris (extends leg at knee and flexes at hip) ○ Vastus lateralis (extend leg at knee joint) ○ Vastus medialis (extend leg at knee joint) ○ Vastus intermedius (extend leg at knee joint) ● Innervated by the femoral nerve ● Action: extending leg at knee, rectus femoris assists in flexion of thigh at hip

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Medial (adductor) compartment ■ Includes: adductor magnus, adductor longus, adductor brevis, and gracilis

Action: adduction of the thigh at the hip ■ Innervated by the obturator nerve Posterior compartment ■ Includes: biceps femoris, semitendinosus, semimembranosus ■ Action: extend thigh at the hip and flex leg at the knee ■ Innervated by the sciatic nerve ■

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INNERVATION OF THE LOWER LIMB MUSCLES ● Sciatic nerve ○ The primary nerve that innervates the lower limb is the sciatic nerve and its branches, the tibial and common fibular nerves ○ Doesn’t innervate quads/anterior thigh (femoral nerve) or adductors (obturator nerve) ○ Posterior thigh ■ Sciatic nerve ○ Anterior leg ■ Deep fibular (peroneal) nerve ○ Posterior leg ■ Tibial nerve ○ Lateral leg ■ Superficial fibular (peroneal) nerve ● Femoral nerve ○ Anterior thigh (flexors of the thigh) ● Obturator nerve ○ Adductors of the thigh (medial compartment) ● Gluteal nerves ○ Glutes ●

Knee joint (structure, movement, ligaments) ○ Articular Surfaces (three articulations)

● Two Femorotibial Articulations ● Lateral femorotibial articulation ● Medial femorotibial articulation ■ One femoropatellar articulation ● Patella: sesamoid bone ■ ** Stability of the knee joint** Joint Capsule ■ External fibrous layer ● fibrous layer attaches to the femur superiorly, just proximal to the articular margins of the condyles. ● Posteriorly, it encloses the condyles and the intercondylar fossa. ● Inferiorly, the fibrous layer attaches to the margin of the articular surface of the tibia (tibial plateau). ● The quadriceps tendon, patella, and patellar ligament serve as a capsule anteriorly— that is, the fibrous layer is continuous with the lateral and medial margins of these structures ■ Internal synovial membrane ● Synovial membrane lines the internal aspect of the fibrous capsule and attaches to the periphery of the parella and the edges of the menisci ● Lines the fibrous layer laterally and medially, but centrally it becomes separated from the fibrous layer Ligaments and Menisci ■ Fibullar (lateral) collateral ligament (LCL) ■ Tibial (medial) collateral ligament (MCL): attaches to meniscus ■ Anterior cruciate ligament (ACL): limits anterior posterior movement ■ Posterior cruciate ligament (PCL): limits anterior posterior movement ■ Menisci of knee joint ■

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Nervous System ● Importance of precentral and postcentral gyri ○ Precentral gyri → motor cell bodies ■ Controls speed of movement, force of muscle contraction, and direction of movement ○ Postcentral gyri → sensory cell bodies ● Structure of a spinal nerve ○ The spinal nerve is formed from dorsal (posterior) and ventral (anterior) rootlets that come from the spinal cord and unite together to form the spinal nerve ■ The sensory or afferent neuron cell bodies are located in the spinal (dorsal root) ganglia ■ The motor or efferent neuron cell bodies are in the ventral (anterior) horn gray matter of the spinal cord

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Structure ■ Cervical nerves = 8 ■ Thoracic nerves = 12 ■ Lumbar nerves = 5 ■ Sacral nerves = 5 ■ Coccygeal nerves = 1 Autonomics ■ Sympathetics = thoracolumbar origin ■ Parasympathetics = craniosacral origin

○ Location + importance of brainstem ○ Location: at the bottom of the brain, right above the spinal cord (contains the midbrain, pons, medulla oblongata)

Contains functional centers associated with the cranial nerves. Contains the long fiber tracts that transmit both sensory impulses to the cerebral cortex and motor impulses for voluntary movements originating in the cerebral cortex. ○ Damage to the brainstem results in sensory and/or motor dysfunction as well as cranial nerve functional deficits. Describe spinal reflexes or spinal stretch reflex (knee jerk reflex) ○ Are an involuntary response to a stimulus. Hence, in it’s simplist form it consists of an afferent (sensory) input and an efferent (motor) neuron. ○ When interneurons are located between the afferent and efferent neurons, reflexes can be more complex ○ Spinal Nerve Reflex ■ Simple Reflex (e.g. Spinal Reflex) ● Muscles contracts when a stretching force is applied to the Patellar tendon ● Tap knee → Sensory receptors in muscle and impulse sent to CNS -> Signal travels along Sensory (Afferent) neuron → Sensory neuron synapses with alpha Motor neuron in spinal cord (nerve fibers and brain compare data)→ Motor neuron sends signal to muscle → Muscle contracts ○ The brain receives the signal but the reflex arc only occurs within the spinal cord ○ Impulse goes into spinal cord, does not have to go to brain ■ Spinal cord compares information with brain ■ Comparing information from the nerve receptors in the muscle to what the CNS tells you to do ● Only contains a afferent and efferent neuron ○ ○

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Functions of reflexes ○ Protection reflexes, like stepping on a nail, typically are simple reflexes ○ A number of important reflexes involve cranial nerves ○ The core of the brainstem contains several centers that integrate not only cranial nerve reflexes but also complex autonomic reflexes such as respiration, GI function and blood pressure ○ Breathing and baroreceptors are complex reflexes which can be voluntarily controlled somewhat ○ Some reflexes can be suppressed with age ■ e.g. Babinski reflex: big toe dorsiflexes (curls upward) and other toes fan outward after sole of foot is firmly stroked. ● Normal in children up to 2 years old but disappears as children get older ● can be suppressed with age ■ E.g. Startle reflex Describe neural pathway for motor innervation of a voluntary muscle including the neuron cell body locations for UMN and LMN and major fiber paths of their axons

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CORTICOSPINAL TRACT is the PRIMARY DESCENDING TRACT Example: Moving left arm ■ UMN begins in Primary Motor Cortex (Precentral Gyrus) on right side of brain → UMN switches to left side of spinal cord where brainstem meets spinal cord →

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UMN travels through Corticospinal tract → UMN synapses with LMN in Anterior horn of spinal cord → LMN travels out of spinal cord and synapses with muscle ○ Upper Motor Neuron (UMN) ■ Cell body location: Precentral gyrus (Primary motor cortex) ○ Lower Motor Neuron (LMN) ■ Cell body location ● Brainstem (cranial nerves) ● Anterior horn of spinal cord (spinal nerves) What are the differences between upper and lower motor neuron defects? ○ UMN Defect

LMN Defect

Spastic paralysis (e.g. Hand is flexed and tight)

Flaccid paralysis (e.g. Muscle becomes limp and cannot contract)

No muscle atrophy

Significant atrophy

Fasciculations/fibrillations not present

Fasciculations/fibrillations present

Hyperreflexia (Stronger reflex)

Hyporeflexia (No reflex)

Babinski reflex present (Can’t inhibit reflex)

Babinski reflex not present

○ Importance of the basal ganglia ○ Consists of strongly interconnected nuclei that influence motor function via feedback to the cortex ○ Receives input from cerebral cortex ○ Sends output to thalamus which then sends information back to cerebral cortex ○ Movement programs are enabled or inhibited by the basal ganglia ○ Monitors progress of movements ○ Initiate voluntary movements and control postural adjustments associated with voluntary movements ○ Abnormalities in basal ganglia result in Parkinson’s and Huntington’s diseases Importance of the cerebellum ○ Affects voluntary muscle contractions ○ Influences the timing and force of contraction of voluntary muscle ○ Influences motor function via feedback loop to cortex and spinal cord ○ Site of motor learning ○ Feedback loop -- it send feedback upstream and back down ○ Facilitates movements (timing and force) ■ Posture/balance

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Sequential movements (for eating, dressing, writing) Rapidly alternating repetitive movements (e.g. tapping on the desk) Smooth pursuit movements (e.g. smoothly point across the room) Acceleration, velocity, trajectory

Nervous System (Somatosensory Pathways) ● Different types of sensation and which fiber tract they are associated with ○

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Type of sensation

Fiber Tract(ascending)

Pain/Temperature

Lateral spinothalamic

Tactile, Proprioception

Dorsal column

Associated with the ascending tract of the spinal cord Crude touch: sense of contact with the skin Tactile discrimination: perception of size/shape of an object. Includes flutter and vibration ○ Proprioception: awareness of limb position/posture and sense of motion ○ Pain: can be sharp, dull, or burning ○ Temperature: ranges from hot to cold Describe the neural pathway for tactile sensation and proprioception including the neuron cell body locations and major fiber path of their axons ○ Primary neuron (cell body in spinal (dorsal) root ganglion) → Primary neuron travels in the Dorsal Column of Spinal Cord → Primary neuron synapses with Secondary neuron in medulla oblongata (same side as sensation) → Secondary neuron crosses over to other side → Secondary neuron synapses with Tertiary neuron in the Thalamus → Tertiary neuron synapses in Postcentral Gyrus Describe the neural pathway for fast pain including the neuron cell body locations and major fiber paths of their axons ○ Primary neuron (cell body in spinal (dorsal) root ganglion) → Primary neuron synapses with Secondary neuron in Dorsal (posterior) horn in spinal cord (same side as pain) → Secondary neuron crosses over to other side → Secondary neurons travels up the Spinothalamic tract → Secondary neuron synapses with Tertiary neuron in the Thalamus → Tertiary neuron synapses in Postcentral Gyrus Significance of the prefrontal cortex ○ Executive functions: planning, social skills ○ Highly responsive to behavioral importance of inputs ○ Can inhibit motor response that requires a delay in response ○ Essential for abstract thinking, foresight, mature judgment, and tactfulness ○ Not concerned with intelligence (cortex deals with intelligence) ○ Injury to prefrontal cortex:

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Diminished sense of responsibility Slovenliness Vulgarity in speech Clownish behavior followed by frequent feelings of euphoria Lack of judgement, insight and concern for future impact of immediate decisions

Nervous System (Autonomic): ● Two neuron system: pre and post ganglionic ● 12 pairs of cranial nerves, their functions, and which ones carry parasympathetic nerves ○ CN I: olfactory → sensory, smell ○ CN II: optic → sensory, vision ○ CN III: oculomotor (Parasympathetic) → motor, moves ciliary muscles, sphincter pupillae, some extrinsic muscles of the eye ○ CN IV: trochlear → motor, moves superior oblique muscle of eye ○ CN V: trigeminal → sensory, face, sinuses, and teeth ■ Also motor, moves muscles of mastication ○ CN VI: abducens → motor, moves lateral rectus muscle of eye ○ CN VII: facial (Parasympathetic) → motor, moves submandibular, sublingual, and lacrimal glands ■ Also sensory, taste to anterior two thirds of tongue, soft palate ○ CN VIII: vestibulocochlear ■ Vestibular nerve = sensory → for equilibrium/motion ■ Cochlear nerve = sensory → for hearing ○ CN IX: glossopharyngeal (Parasympathetic) ■ Motor → stylopharyngeus, parotid gland ■ Sensory → taste: posterior third of tongue, general sensation of pharynx, middle ear cavity ○ CN X: vagus (Parasympathetic) ■ Motor → palate, pharynx, larynx, trachea, bronchial tree, heart, GI tract ■ Sensory → pharynx, larynx, reflex sensory from bronchial tree, lungs, heart ○ CN XI: spinal accessory ■ Motor → sternocleidomastoid and trapezius ○ CN XII: hypoglossal ■ Motor → all intrinsic/extr...