Study Guide for Exam 3
Study Guide for Exam 3 BIOL 2140
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This 17 page Study Guide was uploaded by Kourtney Edwards-Campbell on Friday March 11, 2016. The Study Guide belongs to BIOL 2140 at East Carolina University taught by Elizabeth Jones in Winter 2016. Since its upload, it has received 137 views. For similar materials see Human Anatomy and Physiology in Biology at East Carolina University.
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Date Created: 03/11/16
Fracture- a bone that has been broken or cracked Types of Fractures: Non-aligned fracture- bone that has fractured but is still aligned. Displaced fracture- bone that has fractured but is out of alignment. Complete fracture- bone broken completely through. Incomplete fracture- bone not completely broken, part of it is still attached, may be referred to as a crack. Linear fracture- bone fractured in same direction as the bone/ parallel to the long axis. Transverse fracture- perpendicular to the long axis/ bone fractured on a transverse plane. Open/ Compound fracture- when the bone fractures and penetrates the skin. May cause infection, surgery is needed. Closed/ Simple- bone fractures but doesn’t penetrate the skin. Comminuted fracture- bone fragments into three or more pieces. Particularly common in the aged, whose bones are more brittle. Compression fracture- bone is crushed. Common in porous bones subjected to extreme trauma, as in a fail. Spiral fracture- ragged break occurs when excessive twisting forces are applied to a bone. Common in sports fractures. Epiphyseal fracture- epiphysis separates from the diaphysis along the epiphyseal plate. Tends to occur where cartilage cells are dying and calcification of the matrix occurring. Depressed fracture- broken bone is pressed inward. Typical of skull fractures Greenstick fracture- bones break incompletely. Only one side of the shaft breaks and the other side is bent. Bone Disorders Osteomalacia- soft bones, calcium is not deposited so bones are weak. This leads to pain. Rickets- bones such as pelvis, hips and ribcage deform. The legs may bow because of a lack of vitamin D and/or calcium. Occurs in children. Osteoporosis- bone mass is reduced. Leading to them being porous and lighter. The spongy bone of the spine is most vulnerable. Occurs mostly in older men and women and more so in women. Sex hormones restrain the osteoclast activity. Joint Articulation Functional classification- amount of movement Synarthroses- immovable Ampiarthroses- slightly moveable Diarthroses- freely moveable Structural classification- material binding bones together Fibrous- immovable/ slightly moveable Cartilaginous- rigid/ slightly moveable Synovial- freely moving Joints Fibrous joints Bones joined by fibrous tissue No joint cavity Most immovable 3 types Sutures Only skull bones Wavy edged interlock Filled with minimal amount of very short connective tissue Short connective tissue fibers continuous with periosteum Tightly bind bones but allow growth Ossifies as adult , bones fuse to single unit Now called syntoses (bony junction) Syndesmoses Bones connected by a ligament of fibrous tissue Vary in length Length determines movement Ex: ligaments connecting tibia and fibula Gomphoses A peg-in-socket fibrous joint Tooth in bony alveolar socket only Held by short periodontal ligament Cartilaginous Joint- cartilage attaching bone together Synchondroses Bones to bone joint Hyaline cartilage unites bones Virtually all are immovable (synarthrosis) Are temporary joints, become ossified; completely fused (synostoses) Ex: epiphyseal plates Symphyses Hyaline/ articular cartilage is fused to a pad of fibrocartilage Allows limited movement of joint (amphiarthrotic) Designed for strength, shock, absorption, flexibility Synovial Joints Articulating bones are separated by a fluid-filled joint cavity Allows a lot of movement (diarthrotic) All limb joints 5 distinguishing features Articular cartilage Glassy smooth hyaline cartilage Absorbs compression-protective Synovial cavity Unique to synovial cavity Filled with synovial fluid Articular capsule 2 layers External layer- tough, fibrous dense irregular connective tissue Strengthens the joints Inner layer is synovial membrane composed of loose connective tissue Covers all internal joint surfaces that are not hyaline cartilage Synovial Fluid Occupies the joint capsule Is a blood filtrate ( viscous, viscosity decreases as joint warms) Also found in articular cartilage As joint compresses it oozes out When pressure relieved synovial fluid gets soaked back up into cartilage; weeping lubrication Contains phagocytic cells Removal of cell debris Reinforcing Ligament Strengthen joints Most are intrinsic or capsular Are thickening of fibrous capsule Extracapsular- outside capsule Intracapsular- not really within as these ligaments covered with synovial membrane Bursa and tendon sheaths Often closely associated with synovial joints Are bags of lubricants Bursa Flattened sacs Lined with synovial membrane Contain synovial fluid Provide lubrication and padding Bunion is an enlarged bursa Bursitis- painful inflamed bursa Tendon Sheath- an elongated bursae that wraps completely around a tendon Muscle Function of muscle tissue: convert chemical energy into mechanical energy/ force Types: 1. Skeletal 2. Cardiac 3. Smooth How do they differ? Cell structure Body location Function Source of contraction Skeletal muscle is a discrete organ- made of several types of tissue Muscle fibers Blood vessels Nerve fibers Connective tissue Muscle Structure Epimysium- covering that surrounds whole muscle, made of dense irregular connective tissue Fascicle- a group of muscle fibers. For example, skeletal muscle is made of multiple fascicles Perimysium- covering around fascicle Muscle fibers-muscle cells Long, cylindrical, multinucleate Plasma membrane of muscle fibers is called the sarcolemma. The sarcoplasm is similar to cytoplasm of other cells except: 1. Sarcoplasm has large amount of stored glycogen in glycosomes 2. Myoglobin, is a muscle fibers. Similar to hemoglobin in red blood cells; stores oxygen 3. Contain myofibrils alongside the usual organelles Endomysium- connective tissue that surrounds each muscle fiber. Epi, peri, endomysium are all continuous with one another and with tendons Extra glucose goes to the liver and skeletal muscle by the use of insulin The liver stores glucose as glycogen and glyosomes in skeletal muscles Nerve and Blood Supply Each muscle has an: Nerve Artery One or more veins Enter/exit in center Branch extensively The muscle needs: A continuous supply of O and nu2rients Capillaries- are contorted when muscle is relaxed or contracted Straighten- when muscle stretched Myofibrils Contractile element of muscle cell Each muscle fiber contains 100s-1000s of myofibrils Run parallel and fill entire cell , it’s 80% of the cell volume Myofibril Anatomy Skeletal muscle is striated because of actin and myosin fiber of myofibril. Striations- made from repeating series of A bands, light I band. What gives skeletal muscle it’s striated appearance? The A band and I band of every myofibril line up. This is very important to the function of the skeletal muscle. H-zone-lighter stripe in middle of A band (relaxed muscles only) M-line-bisects H zone and A band Z disc- bisects I bands Sarcomere- region between Z-disc, it’s the functional contractile unit, sarcomere units end to end are what form a myofibril. Myofilaments- fibers within the sarcomere Thick filaments (myosin)- form length of A band Thin filaments (actin)-form I band and extend into A band Nebulin- protein that forms Z discs, anchor thin filaments, connects adjacent myofibrils Desmin- fine protein strands that form M line, hold adjacent thick filaments together Elastin Filaments- composed of giant protein, titin, runs from z disc to myosin and on to M line, holds thick filaments in place, extensible when the muscle is stretching, recoils when returns to original length. Myosin- is the protein that makes up the thick filaments, has two heads and long tail. The tail is two twisted heavy polypeptide chains. The head is the business end of myosin. With two light polypeptide chains. They link thick and think filaments together during contraction. Thick Filament Structure Myosin tails bundle together (forming thick filament) Myosin heads poke outwards Myosin heads in contact with thin filaments (Are binding sites for actin /ATP) Thin Filament Structure Subunit is globular actin (G) Attached in a long polypeptide chain (F actin) F actin folds back on itself to make a twisted double strand Stiffened by 2 strands of tropomyosin In a relaxed muscle tropomyosin blocks active site of actin Troponin Three polypeptide complex TnI- bonds actin TnT-binds to tropomyosin and positions it on actin TnC- binds calcium ions Shape of troponin determines position of tropomyosin Position of tropomyosin determines ability of muscles to contract Sarcoplasmic Reticulum Is the endoplasmic reticulum of the muscle Surrounds each myofibril Network of tubules A-I junction tubules thicker (Terminal Cisternae) Between term. Cis are T-tubules T-tubule Transverse tubules Formed from SR Are tubes that wrap around each myofibril Lumen is continuous with extra cellular space Conduct nerve impulses deep inside muscle cells Contraction of Skeletal Muscle (Sliding Filament Theory) During contraction the actin/myosin overlap increases When stretched the actin/ myosin overlap minimal Muscle Contracting Story Step 1: Exposure of binding sites on actin An action potential brings about the release of calcium ions from the terminal cisternae of the sarcoplasmic reticulum Calcium ions flood into the cytosol and bind to the troponin, causing a change in conformation of the troponin-tropomyosin complex Thus conformational change exposes the binding sites on actin Step 2: Binding of myosin to actin When a binding site on actin is exposed an energized myosin head can bind to it forming a cross bridge Step 3: Power stroke of the cross bridge The binding of myosin to actin brings about change in the conformation of the myosin head, resulting of ADP and inorganic phosphate All the same time, the myosin head flexes, pulling thin filament inward toward the center of the sarcomere. This movement is called the power stroke Step 4: Disconnecting the myosin head from actin In order to disconnect the myosin head from actin, an ATP molecule must bind to its site on the myosin head Step 5: Re-energizing and repositioning the myosin head The release of myosin head from actin triggers the hydrolysis of the ATP molecule into ADP and P 1 Energy is transferred from ATP to myosin head, which returns to its high-energy conformation Step 6: Removal of Calcium Ion Calcium is actively transported from the cytosol into the sarcoplasmic reticulum by ion pumps As the calcium is removed the troponin-tropomyosin complex again covers the binding sites on actin How does actin/myosin overlap change? Myosin head binds the actin (sliding) Myosin head attaches and detaches many times (walking) Thin filament moves toward center of sarcomere Sarcomere shortens, then the muscle fibers shorten 2+ Whole process is triggered by Ca Steps: 1. Muscle relaxed 2. No calcium bound to troponin 3. Tropomyosin blocks myosin binding site on actin 4. Nerve impulse travels to muscle via nerve 5. Nerve impulse delivered to each sarcomere via t-tubule 6. Calcium released from the terminal cisternae 7. Calcium binds to Tnc 8. Change in shape of Tn 9. Moves tropomyosin away from myosin binding site 10.Cross bridge attachment 11.Power stroke 12.Myosin head pivots , pulling on thin filament, which causes sliding 13.ADP is released Cross bridge detachment + ATP (ATP = ADP + Pi) *energy used to ready myosin head for next attachment Myosin head will attach again further along actin filament All myosin heads do not attach and detach simultaneously At any one time some myosin heads are bound to actin- thin filament cannot slide backward Calcium removed by membrane pumps Troponin shape changes Tropomyosin moves back Now blocks cross-bridge , attachment site Muscle relaxes Steps of Rigor Mortis 1. Muscles are contracted 2. Cell death decreases ATP supply ATP synthesis stops. 3. Calcium influx into cell is unstoppable 4. ATP is necessary for cross bridge detachment 5. Without ATP muscles stay contracted, peaked at 12 hours 6. Rigor mortis disappears as muscle protein begin to breakdown Can increase muscle mass by splitting myofibrils Central and Peripheral Nervous System Functions: gather sensory info both internal and external process info , filter and interpret info produce a response: voluntary or involuntary Organization of the Nervous System (CNS and PNS) CNS- brain and spinal cord PNS- nerves not located in the CNS hotlines to and from CNS spinal nerves cranial nerves To CNS (afferent) nerves send impulses to CNS somatic afferent fibers visceral afferent fibers From CNS (efferent) nerves carry impulses from CNS somatic / voluntary nerves autonomic / involuntary nerves 1. sympathetic 2. parasympathetic Nervous Tissue (in PNS and CNS is made of) 1. Nerve cells called neurons which are information messengers. They are the most diverse kinds of cells in the body 2. Supporting cells called neuroglia out number neurons by up to 9:1 Cells are densely packed, with little extra cellular space Astrocytes Most abundant of gilal cell / CNS neuroglia Outnumber neurons by about ten to one Help form a network on which neurons grow Anchor neurons to capillaries Mop up leaked Nts Microglia Protective role Sense microbes and debris Transforms into macrophages and phagocytose debris Microglial cells are defensive cells in the CNS Ependymal Cells Line cavities of brain and spinal cord Are called to circulate CSF Ependymal cells line cerebrospinal fluid-filled cavities Oligodendrocytes Wrap their branches around large nerve fibers Insulating cover or myelin sheath for up to 60 axon Neuroglia of PNS Satellite cells Function unknown Surround neuron cell bodies in ganglia Schwann cells Wrap around large nerves Myelin sheath 1. A schwann cell envelopes axon 2. The schwann cell then rotates around the axon, wrapping its plasma membrane loosely around it in successive layers 3. The schwann cell cytoplasm is forced from between the membranes. The tight membrane wrapping surrounding the axon form the myelin sheath Neurons Cells of nervous system are neurons Are about 100 billion neurons in the CNS Specialized to conduct electrical impulses Normally 80 times per second In epilepsy can fire up to 500 times per second Longevity (>100 yrs) Amitotic- do not divide. Neurogenesis has been shown in other mammals but remains unproven in humans Very high metabolic rate; need constant supply of glucose and oxygen Structure are many different shapes usually large, complex receptive region (dendrites) cell body (soma) conducting region (axon) output region (nerve terminal) Cell Body contains usual organelles nucleus, ribosomes, ER, gogli, mitochondria neurofibrils- maintain cell shape and integrity a cluster of cell bodies is called a nuclei (CNS) a cluster of cell bodies is also called a ganglia (PNS) Dendrites branching extension of the cell body also contain cytoplasm and organelles provide increase in surface are for input signals some are thorny – dendritic spines transmit incoming information to axon hillock by graded depolarizations Axon one per neuron is a projection of cell body arises from axon hillock short or long can branch / axon collaterals usually has terminal branches are conduction component of neurons / transmit impulses terminals are secretory component contains organelles, but no ER or Golgi Therefore axon relies on cell body for protein synthesis Axon decay quickly when damaged Plasma membrane of axon is called axolemma Constant 2 way traffic of molecules inside the axon From cell body to terminal: Anterograde Mitochondria Replacement molecules for axolemma, NT synthesis Transported by the protein kinesin From terminal to cell body: Retrograde Molecules and organelles for degradation and recycling Transported by the protein dynein Myelin Sheath Large, long axon are covered in myelin , which is a fatty protein , it electrically insulates axons Increases transmission of nerve impulses along axon 150x faster than unmyelinated axons Formed by schwann cells Cells wrap themselves around axon many times Tight coil of wrapped membranes A gap is left between adjacent schwann cells called a node of ranvier , therefore axon is exposed at node ; axon collaterals at node Myelinates fiber are called white matter Unmyelinated fibers and cell bodies which are called gray matter Classification of Neurons Structurally: Multipolar 99% of neurons Numerous dendrites 3 or more cell processes Bipolar Have 2 processes (axon and dendrite) Rare. Found in sense organs Retina of eye, olfactory mucosa Unipolar 1 process emerges from cell body Most are sensory neurons in PNS Nerve Impulses Neurons communicate with each other by generating nerve impulses Nerve impulses are electrical currents that travel through neurons In the dendrites and cell body the electrical current is called a graded response In the axon the electrical current is called an action potential What’s the difference? A graded response is a short lived, local changed in membrane potential (depolarization). This change causes current to flow that decreases in strength with distance An action potential is a large, short depolarization event that does not decrease in strength with distance. They occur only in axon, sarcolemma and T –tubules Why the difference? The dendrites and cell body have chemicals and/ or mechanical gated ion channels The axons, sarcolemma and t-tubules have voltage gated ion channels How do you get electrical current to flow? First, all plasma membranes must be polarized at rest, so there is a voltage difference across membrane Why is there a voltage difference between the inside of the membrane and the outside? Because there a leaky ion channels sprinkled all over the membrane of the neuron , they allow potassium to leak out of the cell easier than sodium can leak back into the cell. Therefore, the more positive ions aka potassium leak out of the cell then leak back in sodium. Then the sodium/ potassium pump also pumps in potassium. The net effect; more positive charges collect on the outside surface of the cell called the Resting Membrane Potential There is, therefore, an unequal number of sodium and potassium ions across membrane. The sodium/ potassium pump maintains the concentration gradients Inside cell is more negative than outside Called a polarized state Occur only at membrane Cytoplasm is neutral Extracellular space is neutral So what is depolarization? It is a change in resting membrane potential such that the inside now becomes more positive than it was when at rest.
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