Welcome to Ms. Maalouf's grade 12 IB biology class!



11.2 MovementAnimal Physiology (AHL)Kinesiology: The study of ____________________________ of the human body What happens when somebody moves?549592526797000Your brain sends an impulse (an action potential) through a nerve to a muscle to tell it to contract.Muscles are connected to bones by __________________.When a muscle __________________, it will move the bone.BonesRigid structures for anchoring muscles They contain several different tissues and therefore are organs.Functions: Provide a hard framework to __________________ the body__________________ vulnerable softer tissues and organs Act as levers so that body movement can occurForm blood cells in bone marrowStorage of minerals (ex: calcium and phosphorus)The Human Skeleton:Adult humans have bones26 bones in your 12 pairs of are not considered to be bones.ExoskeletonsSome animals do not have bones but have exoskeletons that provide a similar function.Exoskeletons are external skeletons that surround and protect most of the body surface of crustaceans, insects, and spidersLeversBones and exoskeletons facilitate movement by _______________________ muscles and acting as a _________________.Muscles are attached to the _____________ of bones and the ________________ of exoskeletonsA lever is a rigid rod (the bone) that turns about a _____________ (usually a joint).Levers change the size and direction of forces. 75247510922000Components of LeversLever Arm Effort Force Fulcrum (pivot point) LoadThe body part that is moved (as a result of the Resultant Force) Types of LeversFirst Class Lever:The fulcrum is between When a force is applied, the resultant force causes the load to move up.E.g. Second Class Lever:The load is between There is a because less for is required.E.g. Third Class Lever:The effort force is between No mechanical advantage – more force is required to lift the load.E.g. 5124450-20955000Muscles and TendonsSkeletal Muscles are attached to bonesTendons are what attach muscles to bonesTendons are cords of dense connective tissueMuscles provide the force necessary for movement by shortening the length of their fibres. Antagonistic Muscle ActionMuscles work in antagonistic pairs to achieve movementWhen one muscle contracts, the other relaxesWhen the biceps contract, ____________________________________________________________________________________________________________________________________e When the triceps contract, _______________________________________________________1257300265430_____________________________________________________________________________, it causes the bones to straighten. The bicep474345018224500234188025844500Antagonistic Muscle Pairs in Insect LegsInsect legs also have antagonistic muscles to flex and extend the joint by: When the grasshopper prepares to jump:FLEXING: The flexor muscles will contract bringing the tibia and tarsus in a “Z” position.The extensor muscles are relaxed. EXTENDING:The extensor muscles contract strongly, causing the tibia to extend, making the insect jump. JointAlso called an articulation or arthrosisThe point where 2 or more bones contact one anotherJoints cause mobility and hold the body togetherMost joints include:BonesLigamentsMusclesTendonsnervesAnnotate (label) a Human Elbow Joint:29813256000750012858751660525001400174143827400Elbow Joint PartDescriptionSpongy BoneCartilageJoint CapsuleSynovial FluidSynovial MembraneLigamentsBicepsTricepsHumerusRadiusUlnaThe elbow joint is called a ___________________________ because of the presence of the synovial cavity.There is a rich supply of blood to joints.If blood vessels supplying the joint gets damaged and there is local bleeding, it may result in swelling of the areaClasses of Joints:1. Synovial Joints Have a lubricating synovial cavity Provides lots of 2. Cartilaginous JointsJoin bones with cartilage.E.g. 3. Fibrous JointsJoins bones with connective tissue (collagen) E.g. 5200015-57150000Joint TermsFlex and ExtendExample: Movement that moves your leg back and forth (like a pendulum)47828208064500Flexion = decrease the angle between the connecting bonesExtension = increase the angle between the connection bonesAbduction and adduction Example: Moving your leg sideways (away from the center of the body)Abduction = bones moves away from body’s midline481076010604500Adduction = bones move toward body’s midlineRotation Bone moves along its own longitudinal axisHinge Joints Provides an opening-and-closing type of movement like the action of a doorThis movement is in one direction – flex and extendExample: the elbow joint, the knee joint13716001092200030099002540000Ball and Socket JointsAllows for movement in several directionsFlex and extendAbduction and adductionRotational movementExample: Hip Joint the head of the femur is ball shape and fits into a cup like depression of the hip bone120015116065500388620016065500Joints and MovementThe structure of the joint (including the joint capsule and ligaments) determine the movements that are possible.Knee JointHip JointTypeSynovial JointHinge JointSynovial JointBall and SocketRoleInvolved in movement of the leg and required for walkingInvolved in the movement of the leg and required for walkingPossible MotionsFlex and ExtendSmall amount of rotationFlex and ExtendAbduction and AdductionRotationRange of MovementMovement in one directionMovement in many directions (multiaxial)Types of MuscleHuman body has 3 types of muscles:_____________________________________________________________________________________________________________________________________________________________________________________________________________________Skeletal Muscle/Striated MuscleSkeletal muscle is characterized by a hierarchy of smaller and smaller units.A skeletal muscle consists of a _______________ of long fibres running parallel to the length of the muscle.Each __________________________ is a ___________________________ with multiple nuclei, reflecting its formation by fusion of many embryonic cells.The arrangement of proteins within muscle fibres creates a banded appearance of stripes under a microscope, which is why it is called striated muscle.A muscle fibre is itself a bundle of smaller _________________________ arranged longitudinally. 7334251016000034861502540Parts of a Muscle FibreEach muscle cell was originally many cells fused together, which is why a muscle cell has many nuclei.Sarcolemma: ___________________________________________________________________Sarcoplasm: __________________________________________________________________muscleWithin the sarcoplasm there are multiple mitochondria for ATP production (because muscle contractions require a lot of energy)Sarcoplasmic Reticulum: membrane found within the sarcoplasm (similar to the ER)Stores and releases _________________________ into the sarcoplasm which will trigger a _________________________________Myofibrils: __________________________________________________________________________Create the striated (striped) pattern of light and dark skeletal musclesComposed of two types of myofilaments:Thin Filaments: _________________________________________________________Thick Filaments: ________________________________________________________Sarcomere: The basic ________________________________________of the muscle (a segment of a myofibril)379095016954500SarcomereA sarcomere is found between two ____________Thin actin filaments form the ___________They are attached to the Z line and project toward the centre of the sarcomereThick myosin filaments are found in the __________In the _______________, myosin and actin overlap The thin filaments do not extend completely across the sarcomere, so the gray _____________ in the centre of the A band contains only thick filaments.470535015430500Muscle ContractionWe can explain much of what happens during contraction of a whole muscle by focusing on a single muscle fibreAccording to the Sliding Filament Model, myosin-actin interactions underlie muscle fibre contraction.3743325000Myofilaments – Myosin Thick FilamentsThick filaments contain several myosin molecules bundled togetherEach myosin molecule consists of a long “__________” region and a globular “________” region extending to the side. The tail adheres to the tails of other myosin molecules that form the ________________________ The head binds to _____________, which powers muscle contractionsH Zone: filaments have no heads or tailsMyofilaments – Actin Thin FilamentsThin filaments contain strands of actin and two strands of regulatory proteins: ______________________________________________________________________Two strands of tropomyosin wind around the actin filament covering the binding site for the myosin hooks.This prevents the muscle from contracting.Sarcomere Arrangement15240059690004508367-134391100Sliding Filament Model of Muscle ContractionNeither thin nor thick filaments change in length when the sarcomere shortens.Filaments slide past each other longitudinally producing more overlap between the thin and thick filaments. A) Relaxed Muscle FibreIn a relaxed muscle fibre, the I bands and H zone are relatively ___________.1683533-77283900(B) Contracting Muscle FibreDuring contraction, the thick and thin filaments slide past each other, reducing the width of the I bands and H zone and ________________________ the sarcomere. 16819389096700(C) Fully Contracted Muscle FibreIn a fully contracted muscle fibre, the sarcomere is shorter still. The thin filaments overlap, eliminating the _________________. The _______________ disappear as the ends of the thick filaments contact the Z lines. 161793617145Recap: Sliding Filament TheoryActin and myosin slide over each other to make the muscle shorter (actin and myosin stay the same size!)Little “hooks” on the myosin filaments attach to the actin and pull them closer to the centre of the sarcomere.This shortens the sarcomere and the overall length of the muscle fibre – muscle contraction!Myosin then releases the actin and repeats the hooking and pulling action further down the actin.This is done with ATP energy (from mitochondria!) As the filaments slide over each other, the H bands disappears and the I band shortens.Which of the following diagrams shows a relaxed muscle and which shows a contracting muscle?The Role of Calcium & Regulatory Proteins in Muscle ContractionA skeletal muscle fibre contracts only when stimulated by a motor neuron. When the muscle fibre is at rest, the myosin binding sites on the thin filament are ___________________ by regulatory protein ______________________. For the muscle fibre to contract, those binding sites must be ______________________.This is achieved when an action potential arrives at the muscle and causes the sarcoplasmic reticulum to release calcium ions (Ca2+) into the sarcoplasm.The Ca2+ bind to the troponin complex, which controls the position of tropomyosin on the thin filament. Calcium binding rearranges the tropomyosin-troponin complex, exposing the myosin binding sites on the thin filament. The myosin head is bound to ATP already and is in its low-energy configuration.The myosin head will hydrolyze ATP into ADP and Pi (but will still be attached to myosin head) and is in its high-energy configuration. The myosin head can now bind to the actin binding sites on the thin filament, forming a _________________4410356-36420900The ADP and Pi dissociate from the cross-bridge and the myosin head bends, pulling actin filaments toward the M line. This is called the _____________________. It causes the myofilaments to slide over each thus the muscle fibre contracts. The cross bridge is broken when a new molecule of ATP binds to the myosin head. 1912971636200The process may repeat with the heads attaching to binding sites further along the actin filament. Muscle RelaxationContraction cycles will continue as long as ATP is available and Ca2+ is present in the sarcoplasmWhen the nerve impulse stops, Ca2+ move back into the vesicle of the sarcoplasmic reticulum by active transportThis causes the binding sites on the actin to be covered again (so myosin cannot bind)The muscle will relax.Cardiac Muscle Cells (p 685)The structure of cardiac muscle cells allows for propagation of stimuli through the heart wall.Remember, cardiac muscle tissue is unique.It is also striated in appearance, and the arrangement of myofilaments is similar to skeletal muscle.How do they differ from skeletal muscle fibres?Cardiac muscle cells are They have only per cell.Cardiac muscle contraction is not under voluntary control Many cardiac muscle cells contract even in the absence of stimulation by nerves for the entire life of the organism!The cells are ______________________ There is a specialized junction called an ______________________________where the end of one cell meets the end of another cellThe intercalated disc consists of a double membrane containing ________________________ which are channels that provide a connection between the cytoplasm of adjacent cells.This allows for the rapid movement of ions from one cardiac cell to the next, with low electrical resistance.So, their Y-shape and gap junctions allows them to be electrically connected34266817420340028891074580000This means a wave of depolarization can easily pass form one cell to a network of other cells leading to synchronization of muscle contraction allowing for both atria and both ventricles to contract smultaneously as if it was one large cell. ................
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