MCB 244: Final Exam (4) Complete Study Guide
MCB 244: Final Exam (4) Complete Study Guide MCB 244
Popular in Human Anatomy and Physiology I
Popular in Biology
This page Study Guide was uploaded by Laura Kunigonis on Tuesday December 8, 2015. The Study Guide belongs to MCB 244 at University of Illinois at Urbana-Champaign taught by Dr, Chester Brown in Fall 2015. Since its upload, it has received 447 views. For similar materials see Human Anatomy and Physiology I in Biology at University of Illinois at Urbana-Champaign.
Reviews for MCB 244: Final Exam (4) Complete Study Guide
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 12/08/15
MCB 244 Final Exam Study Guide Chapter1 Integumentary Systemmajor organs Skin hair sweat glands nails func ons Protects against environmental hazards helps regulate body temp provides sensory information Skeletal System major organs Bones cartilages associated ligaments bone marrow Skeletal System functions Provides support and protection for other tissues stores calcium and other minerals forms blood cells Muscular System major organs Skeletal muscles and associated tendons Muscular System functions Provides movement provides protection and support for other tissues generates heat that maintains body temp Nervous System major organs Brain spinal cord peripheral nerves sense organs Nervous System functions Directs immediate responses to stimuli coordinates or moderates activities of other organ systems provides and interprets sensory information about external conditions Endocrine System major organs Pituitary gland thyroid gland pancreas adrenal glands gonads endocrine tissues in other systems Endocrine System functions Directs longterm changes in the activities of other organ systems adjusts metabolic activity and energy use by the body controls many structural and functional changes during development Cardiovascular System major organs Heart blood blood vessels Cardiovascular System functions Distributes blood cells water and dissolved materials including nutrients waste products oxygen and carbon dioxide distributes heat and assists in control of body temp Lymphatic System major organs Spleen thymus lymphatic vessels lymph nodes tonsils Lymphatic System functions Defends against infection and disease returns tissue fluids to the bloodstream Respiratory System major organs Nasal cavities sinuses larynx trachea bronchi lungs alveoli Respiratory System functions Delivers air to alveoli sites in lungs where gas exchange occurs provides oxygen to bloodstream removes carbon dioxide from bloodstream produces sounds for communication Digestive System major organs Teeth tongue pharynx esophagus stomach small intestine large intestine liver gallbladder pancreas Digestive System functions Processes and digests food absorbs and conserves water absorbs nutrients stores energy reserves Urinary System major organs Kidneys ureters urinary bladder urethra Urinary System functions Excretes waste products from the blood controls water balance by regulating volume of urine produced stores urine prior to voluntary elimination regulates blood ion concentrations and pH Male Reproductive System major organs Testes epididymides ductus deferentia seminal vesiclesprostate gland penis scrotum Male Reproductive System functions Produces male sex cells sperm seminal fluids and hormones sexual intercourse Female Reproductive System major organs Ovaries uterine tubes uterus vagina labia clitoris mammary glands Female Reproductive System functions Produces female sex cells oocytes and hormones supports developing embryo from conception to delivery provides milk to nourish newborn infant sexual intercourse Homeostasis state of equilibrium opposing forces are in balance the ability of an organism to harness mechanisms for the preservation maintenance of an almost constant internal state in the face of perturbations first put forst by Claude Bernard and later championed by Walter Cannon systems respond to external and internal changes to function within a normal range body temp fluid balance etc both passive and active mechanisms involved Negative Feedback Causes function to slow or stop Positive Feedback An initial stimulus produces a response that exaggerates or enhances the original change in conditions rather than opposing Extrinsic Regulation Simultaneous control of several systems by nervous or endocrine input Ex Nervous system control of heart rate and central and peripheral blood flow to activate tissues in low 02 Autoregulation intrinsic Automatic response in a cell tissue or organ to some environmental change Ex Cells release chemicals in response to decline in 02 during exercise that increase blood vessel dilation and thus provide blood flow to active tissues Chapter 2 Greatest to lowest power output Creatine Phosphategt glucose fermentationgt glucose oxidationgt fat oxidation Greatest to lowest energy availability Fatty Acid Oxidationgt glucose oxidationgt glucose fermentationgt creatine phosphate ls Protein generally stored for energy No fats and carbohydrates are generally preferred for energy storage General Metabolic Pathway used for the catabolism of Fats Fats gt Fatty Acids gt acetylCoA gt Krebs Cycle General Metabolic Pathway used for the catabolism of Carbs Carbs gt glucosesugars gt glycolysis gt Pyruvate OR lactate limiting 02 General Metabolic Pathway used for the catabolism of Proteins Proteins not stored for catabolic purposes gt amino acids gt acetylCoA gt fed into Krebs Cycle NADPH NADP Coenzyme that plays a critical role as a reducing agent Gives electrons in the Electron Transport Chain NADHNAD Coenzyme which acts as an oxidizing agent accepts electrons in the TCA cycle Chapter 4 Steps for Tissue inflammation and repair Tissue is exposed to a pathogentoxin General defense mechanism is activated Mast Cells are activated and release a variety of chemicals These chemicals stimulate Inflammation Inflammation Produces indications of injury Increases blood flow blood vessel permeability and pain Increases local temp oxygen and nutrient delivery Increases phagocytosis and removal of wastes and toxins Regeneration Repair that follows once the damaged tissue has been stabilized Fibroblasts Lay down collagenous framework scar tissue Chapter 5 Functions of the Integument Protect tissue and organs Secrete salts water and organic Maintains Body temperature Synthesizes Vitamin D D2 and D3 Stores Lipids Detects sensory modalities touch pressure pain and temperature Connects to the circulatory system blood vessels in the dermis and the nervous system sensory receptors Protects and interacts with all organ systems Changes in skin appearance can be used to diagnose disorders in other systems General Stages of Skin Regeneration Bleeding occurs at injury site immediately after injury Mast Cells in region trigger inflammatory response Scab forms in several hours Then cells of stratum basale are migrating along the edges of the wound Phagocytic cells are removing debris and more are arriving through the enhanced circulation of the area Clotting around the edges of the affected area partially isolates the region One week later the scab has been undermined by epidermal cells migrating over the meshwork produced by fibroblast activity Phagocytic activity around the site is almost over Fibrin clot is breaking up Several weeks later scab has been shed and epidermis complete A shallow depression marks injury site but the fibroblasts in the dermis continue to create scar tissue that will gradually elevate the overlying epidermis lntegument functions independent of nervous system to maintain homeostasis Germinative basal cells of epidermis regenerate tissue Mast Cells Trigger inflammatory response Phagocytic Cells Remove Debris from injury site Age related changes in integumentary system Stem cell activity declines skin becomes thinner and repair is difficult Langerhans cells decrease reduced immune response Vitamin D3 production declines calcium absorption declines and bones become brittle Blood supply to dermis declines tend to feel cold Hair follicles die or produce thinner hair terminal gt vellus peach fuzz lacks a medulla Dermis thins and becomes less elastic loses collagen gt wrinkles Sex characteristics fade Fat deposits spread out Hair patterns change Mesenchymal cells of dermis regenerate connective tissue Vellus Hair Peachfuzz Covers body At puberty hormones can trigger switch to terminal hairs Present at armpits pubic area and limbs Terminal Hairs Head eyebrows and eyelashes Thick coarse pigmented Chapter 6 Ossification Replacing other tissues with bone Two Main forms Intramembranous and endochondral Intramembranous Ossification dermal Ossification Produces dermal bones such as mandible and clavicle collarbone There are three main steps 1 Mesenchymal cells aggregate and differentiate into osteoblasts they begin ossification 2 As spicules interconnect they trap blood vessels within the bone 3 The bone assumes structure of spongy bone over time Endochondral Ossification Process for most bones Ossifies bones that originates as hyaline cartilage Six main steps in endochondral ossification 1 Chondrocytes near the center of the shaft increase in size and they begin to disintegrate leaving cavities within the cartilage 2 Blood vessels grow around the edge and the perichondrium converts to osteoblasts a superficial layer of bone covers the outside of the cartilage 3 Blood vessels penetrate and invade the central region spongy bone is made in the middle and spreads towards ends 4 Remodeling occurs growth of bone 5 Capillaries and osteoblasts migrate to epiphyses creating secondary ossification centers 6 Epiphyses are filled with spongy bone Sequence of steps involved in bone lengthening Lengthening in our long bones occurs at specialized regions called epiphyseal plates Epiphyseal plates Specific regions in long bones where lengthening occurs Contain epiphyseal cartilage that actively osteogenesis that increases the length of the region Epiphyseal Lines When long bone stops growing after puberty epiphyseal cartilage disappears ls visible on xrays as an epiphyseal line Appositional Growth Increasing of bone diameter during endochondral ossification grows from inside outward Calcification Depositing calcium salts Occurs during ossification and in other tissues Osteoblasts Immature bone cells mature ones are called osteocytes Secrete osteoid matrix compounds not yet calcified to bone turn into osteocytes when surrounded by bone matrix Osteoid Matrix compounds not yet calcified to bone Osteocytes Mature Osteoblasts Osteoprogenitor Cells Assist in fracture repair Mesenchymal cells that divide to produce osteoblasts Located in endosteum the inner cellular layer of periosteum Osteoclasts Secrete acids and proteindigesting enzymes Dissolve bone matrix and release stored materials Known as osteolysis Diaphysis Shaft of bone Epiphysis Ends of bone Metaphysis In between Remodeling Lifeline process of replacingrecycling of bone matrix and minerals Sponge bone can be converted into compact bone Calcitriol Helps absorb calcium from digestive tract Vitamin D3 Parathyroid hormone PTH Increases plasma calcium ion levels by stimulating osteoclasts calcium released lncreasing intestinal absorption of calcium needs calcitriol Decreasing calcium excretion at kidneys lower rate less lost Calcitonin Decreases plasma calcium ion levels lnhibiting osteoclasts calcium stored Decreasing rate of intestinal absorption of calcium lncreasing calcium excretion of kidneys Steps for fracture repair 1 Hematoma formation Produces a clot establishes a fibrous network bone cells in that area die 2 Soft Callus formation Cells of endosteum and periosteum divide and migrate into fracture zone 3 Calluses form to stabilize break External callus of cartilage and bone surrounds break lnternal callus develops in medullary cavity organizes 4 Bone formation osteoblast activity increase Replace central cartilage of internal callus with spongy bone External callus replaced with compact bone 5 Bone Remodelling osteoblasts and osteoclasts remodel the fracture reduces bone calluses Chapter 10 Functions of Skeletal Muscle tissues Produce skeletal movement Maintain posture and body position support soft tissue Guard entrances and exits Maintain body temp Store nutrient reserves 4 Major steps of skeletal muscle contraction Neural Stimulation Excitation contraction coupling Muscles contraction Relaxation of Muscle Action potential all or none depolarization in membrane potential travels down motor neuron and reaches nerve terminal at neuromuscular junction Depolarization of synaptic terminal opens Ca channels gt Ca influx causes ACh to be released via exocytosis into synaptic cleft ACh binds to nicotinic receptors on motor end plate sarcolemma membrane opens nonselective cation channels Cations Na rush into sarcolemma depolarization of sarcolemma Depolarization is transmitted to Ttubules deep in muscle Depolarization activates Dihydropyridine Receptors DHPR of Ttubules which in turn mechanically activate Ryanodine Receptors of SR RyR1 DHPR activation releases a small amount of Ca to sarcoplasm RyR1 open and release large amounts of Ca into sarcoplasm Ca binds to troponin on thin filaments conformation change moves tropomyosin uncovering active sites on actin so that myosin heads can bind Myosin binds to actin crossbridge Pivots towards M line Contraction power stroke CaATPase pumps in SR take up Ca as soon as it is released in sarcoplasm to minimize latency period before another excitation Tropomyosin goes back to original form blocking active sites on actin when Ca is no longer bound to troponin relaxation occurs T tubules lnvaginations of sarcolemma that reach deep inside the cell to transmit changes in transmembrane potential to structures inside cell DHPR On Ttubules Release a small amount of Ca upon activation Mechanically linked to RyR1 on SR and releases a lot of Ca Thin filaments Component of myofilaments Protein actin Thick filaments component of myofilaments Protein myosin Troponin Binds to tropomyosin and has a site for Ca When Ca binds Troponin changes conformation to move tropomyosin away from the myosin binding site of actin Tropomyosin Covers the myosin binding site on the thin filaments Bound to troponin A change in conformation of troponin induced by Ca causes Tropomyosin to be moved away from the active site CaATPase Pump In SR takes up Ca as soon as it is released in Sarcoplasm to minimize latency period before another excitation ABand Whole width of thick myosin filament Looks dark microscopically M Line At midline of sarcomere Center of each thick filament Middle ofA band Attaches neighboring thick filaments HBand Lighter region on either side of the M line Contains thick filaments only Zone of overlap Triads encircle zones of overlap Ends of Aband Place where thin filaments intercalate between thick filaments LBand Contains thin filaments outside zone of overlap Not whole width of thin filament Z linedisc Centers ofl bands Constructed of Activinsanchor thin filaments and bind neighboring sarcomeres Titin Proteins Bind thick filaments to Zline stabilize the filament Fast glycolytic fibers Type llb Myosin ATPase works quickly ATP production via glucose fermentation anaerobic Large diameter fibers Many myofilaments and high glycogen supply Few Mitochondria Fast to act and powerful but quick to fatigue Slow Oxidative Type Myosin ATPase works slowly Specialized for aerobic respiration Many mitochondria Extensive blood supply Myoglobin Small fibers Slow to contract and produce low tension but resist fatigue Metabolize lipids glucose and amino acids Intermediate Fast Oxidative Type Ila Qualities of both fast and slow fast acting but perform aerobic respiration so slow to fatigue Intermediate levels of myoglobin and capillarity Physical conditioning can convert some fast fibers into intermediate fibers for stamina Agerelated changes in muscular system Skeletal muscle fibers become smaller in diameter skeletal muscles become less elastic and develop increasing amounts of fibrous tissue decreased tolerance for exercise Decreased ability to recover from muscular injuries decreased of satellite cells Chapter 12 Organization of the Nervous System CNS is made up of the brain and spinal cord PNS consists of efferent and afferent Efferent consists of Somatic and Autonomic Efferent Nervous System Carries motor command From CNS to PNS and effectors Made up of the Somatic Nervous System and Autonomic Nervous System Somatic Nervous System Apart of the Efferent division of the PNS Controls skeletal muscle contraction voluntary and involuntary reflexes muscle contractions Autonomic Nervous System Apart of the Efferent division of the PNS Controls subconscious actions contractions of smooth muscle and cardiac muscle Consists of Parasympathetic and sympathetic nervous system Parasympathetic Nervous system Has relaxing effects Sympathetic Nervous system Has stimulating effect Afferent Nervous System Carries sensory information From PNS sensory receptors to CNS CNS Integrate information from different parts of the body and coordinate movements based on them Made up of Brain and Spinal Cord Sensory Data from inside and outside body Motor commands control activities of peripheral nerves Higher functions of brain Intelligence memory learning emotion PNS Deliver sensory info to the CNS Carry motor commands to peripheral tissues and systems Made up of all the other nerves in the body outside of the brain and spinal cord Anaxonic Neuron Have more than two processes but axons cannot be distinguished from dendrites Bipolar Neurons Have two processes separated by the cell body Unipolar Neurons Have a single elongate process with the cell body situated to the side Multipolar Neurons Have more than two processes There is a single axon and multiple dendrites Perikaryon Cytoplasm of soma RER and Ribosomes in soma Produce Neurotransmitters and Cytoskeleton Nissl Bodies Dense areas of RER and ribosomes Make neural tissue appear gray Neurofilaments In place of microfilaments and microtubules Neurofibrils Bundles of neurofilaments that provide support for dendrites and axons Initial segment of axon attaches to axon hiock Axon Hillock Thick section of cell body that attaches to initial segment tnggerzone Axolemma Specialized cell membrane that covers axopasm Collaterals Branches of a single axon Telodendria Fine extensions of distal axon Synaptic Knob Area of an axon of a presynaptic Neuron Contains synaptic vesicles of neurotransmitters Sensory Neuron Convey sensory information from external stimuli to the central nervous system Motor Carry signals from the spinal cord to muscles Interneurons Connect different neurons neither motor or sensory Most are located in brain spinal cord and autonomic ganglia Distribution of information coordination of motor activity and higher func ons Interoceptors organs Monitor digestive respiratory cardiovascular urinary reproductive provide sensations of distension bloated deep pressure pain Exteroceptors senses Provide info about external environment in form of external senses touch temp pressure or distal senses sight smell hearing Proprioceptors skeletal muscles Monitor position and movement of skeletal muscles and joints Four Neuroglia in the CNS Ependymal Cells Astrocytes Oligodendrocytes Microglia Ependymal Cells Neuroglia of the CNS Form epithelium called Ependyma Line central canal of spinal cord and ventricles of brain Secrete cerebrospinal fluid CSF Have cilia or microvilli that circulate CSF monitor CSF contain stem cells for repair Astrocytes Neuroglia of the CNS Maintain bloodbrain barrier isolates CNS Create 3D framework for CNS Repair damaged neural tissue Guide neuron development Control interstitial environment Oligodendrocytes Neuroglia of CNS Processes contact other neuron cell bodies Wrap around axons to form myelin sheaths Myelination Increases speed of action potentials Myelin insulates myelinated axons Make nerves appear white Microglia Neuroglia of CNS Migrate through neural tissue Clean up cellular debris waste products and pathogens phagocytic cells Two Neuroglia in the PNS Satellite Cells Schwann Cells Schwann Cells Neuroglia of the PNS Also known as Neurolemmocytes Form myelin sheath neurilemma around peripheral axons One schwann cell sheaths one segment of axon Many Schwann cells sheath entire axons Satellite Cells Neuroglia of PNS Also called amphicytes Surround ganglia Regulate environment around neuron Graded Potential Temporary localized change in resting potential Caused by stimulus Equilibrium Potential Depends on type of ion K 90mV Na 66mV NaK ATPase Uses ATP to bring in 2 potassium ions from the extracellular fluid and take out 3 sodium ions from the intracellular fluid Serves to stabilize the resting potential to counteract tendency of Na to enter cell and K to enter the cell Maintain Resting potential at 70mV Permeability of plasma membrane for K High Permeability of plasma membrane for Na Low So Na contributes less than K to normal resting potential Chemical Gradient for Na More Na outside of the cell than inside Na travels into the intracellular fluid Electrical Gradient of Na More negative inside of cell so Na flows towards Intracellular fluid Net electrochemical gradient of Na Towards the inside or intracellular fluid Chemical Gradient for K More K inside of cell than outside K travels out of cell Electrical Gradient of K Towards the intracellular fluid because inside of cell is more negative However this is more smallerweaker than chemical gradient Net electrochemical gradient of K Towards the outside of the cell Chemically gated channels Open when a specific ligand Ex ACh binds to them Typically found on neuron cell bodies and dendrites This would cause a graded potential Voltagegated channels Open and close according to changes in transmembrane potential Characteristic of excitable membranes like axons muscle sarcolemma and cardiac muscle Mechanically Gated Channels When the membrane becomes distorted the channel opens up Found in sensory receptors that respond to touch and pressure changes Depolarization A shift in transmembrane potential toward 0 mV Repolarization When stimulus is removed the transmembrane potential goes back to resting potential Hyperpolarization Increasing the negativity of the resting potential due to opening potassium channels Four steps in Generation of Action Potential 1 Depolarization to threshold due to graded potentials lnitial suprathreshold stimulus changes the resting potential to 60mV to 55mV threshold level of voltagegated sodium channels 2 Activation of Na channels voltage gated Rapid depolarization occurs as Na ions rush into cytoplasm 3 Inactivation of Na channels Activation of K channels At 30 mV Repolarization begins K rushes out of cell to drive the membrane potential down towards resting potential 4 Return to normal permeability K channels begin to close when membrane reaches normal resting potential 70mV K channels finish closing when membrane is hyperpolarized to 90mV Action potential is over Absolute Refractory Period Sodium channels open or inactivated No action potential possible Relative Refractory Period Membrane potential almost normal Very large stimulus can initiate action potential Graded Potential vs Action potential Graded Potential Depolarizing or hyperpolarizing No threshold value Amount of depolarization or hyperpolarization depends on intensity of stimulus Passive spread from site of stimulation Effect on membrane potential decreases with distance from stimulation site No refractory Period Occur in most plasma membranes Action Potentials Always depolarizing Depolarization to threshold must occur before action potential begins Allornone Action potential at one site depolarizes adjacent sites to threshold Propagated along entire membrane surface without decrease in strength Refractory Period occurs Occurs only in excitable membranes Continuous Propagation Unmyelinated Axons Steps 1 Action potential in segment 1 depolarizes membrane to 30 2 Depolarizes second segment to threshold Second segment develops action potential Saltatory Propagation Action potential along myelinated axon Faster and uses less energy than continuous propagation Myelin insulates axon Local currentjumps from node to node depolarization only occurs at nodes 3 types of Nerve Fibers Myelinated A and B Diameter A is largest C is smallest Speed A is fastest C is slowest Chemical Synapses Found in most synapses between neurons Found in all synapses between neurons and other cells Cells not in direct contact Action potential may or may not be propagated to postsynaptic cell depending on Amount of neurotransmitter released Sensitivity of postsynaptic cell Electrical synapse Locked together at gap junctions Allow ions to pass between cells Produce continuous local current and action potential propagation Found in areas of brain eye ciliary ganglia Steps involved in neurotransmitter at chemical synapse Action potential arrives at synaptic knob Calcium ions enter synaptic knob which triggers exocytosis of ACh into synaptic cleft ACh binds to receptors on the postsynaptic membrane and triggers an action potential AChE breaks down ACh into acetate and choline Direct Effects of Neurotransmitters and Neuromodulators lnotropic effects affect muscle contraction like heart muscle Openclose gated ion channels and produce gated potentials Indirect effects via G Proteins of Neurotransmitters and Neuromodulators Receptors are Gprotein coupled receptors Work through intracellular second messengers Enzyme complex that binds GTP which serves as the link between neurotransmitter first messenger and second messenger Activates intracellular enzymes Indirect effects of Neurotransmitters and Neuromodulators via Intracellular enzymes Bind to Intracellular enzymes in target cells Generally things that can diffuse through the membrane Two types of Postsynaptic Potentials 1 Excitatory postsynaptic potential EPSP Graded depolarization of postsynaptic membrane 2 Inhibitory postsynaptic potential IPSP Graded hyperpolarization of postsynaptic membrane Two types of synaptic summation Temporal summation one depolarizing stimuli arrives and then another right after that adds to the intensity and generates an action potential Spatial Summation Multiple depolarizing stimuli arrive simultaneously and activate a new action potential Presynaptic Inhibition Anaxonic synapse decreases the amount of neurotransmitter that is released by the presynaptic membrane Inactivation of calcium channels of presynaptic neuron Presynaptic facilitation Anaxonic synapse increases the amount of neurotransmitter that is released by the presynaptic membrane Activation of calcium channels of presynaptic neuron Chapter 14 What are the anatomical components of the cerebellum Cerebellar Hemispheres separated at midline by vermis Vermis narrow band of cortex Anterior Posterior lobes separated by primary fissure Flocculonodular lobe below fourth ventricle Arbor vitae quottree of lifequot highly branched internal white matter of cerebellum relays information to Purkinje cells Cerebellar cortex the stuff that surrounds the internal white matter in the cerebellum Peduncles superior middle and inferior link cerebellum with brain stem cerebrum and spinal What are the major functions of the cerebellum Adjusts postural muscles Fine tunes conscious amp subconscious movements Primary somatosensory cortex know where it is located in the brain and its major Function receive general somatic sensory information from receptors of touch pressure pain Primary motor cortex know where it is located in the brain and its major function neurons of the primary motor cortex direct voluntary movements by controlling somatic motor neurons in the brain stem and spinal cord Know where the various sensory and motor association areas are in the cortex and have a basic understanding of their general functions Sensory association areas 0 Monitor and interpret arriving information at sensory area of cortex Somatic sensory association areas 0 Somatic sensory association area interprets input to primary sensory cortex eg recognizes and responds to touch Visual association area 0 Visual association area interprets activity in visual cortex Auditory association area 0 Auditory association area monitors auditory cortex Where are the locations and functions of the following general interpretive area Wernicke39s area speech center Broca39s area prefrontal cortex general interpretive area Wernicke39s area 0 present in only one hemisphere usually left 0 receives information from all sensory association areas 0 coordinates access to complex visual and auditory memories speech center Broca39s area 0 is associated with general interpretive area 0 coordinates all vocalization prefrontal cortex 0 integrate information from sensory association areas 0 performs abstract intellectual activities Have a basic understanding of the concept of hemispheric lateralization and know the functions attributed to the left and right cerebral hemispheres Functional differences between left and right hemispheres Each cerebral hemisphere performs certain functions that are not ordinarily performed by the opposite hemisphere The left hemisphere o In most people left brain dominant hemisphere controls Reading writing and math Decision making Speech and language The right hemisphere 0 Right cerebral hemisphere relates to Senses touch smell sight taste feel Recognition faces voice inflections Chapter 15 Afferent Division of the Nervous System Includes Receptors Sensory Neurons Sensory Pathways Efferent Division of the Nervous System Includes Nuclei Motor Tracts Motor Neurons The detection of stimuli depends on the action of sensory units and their Receptor Sensitivity Receptive Field Receptor Sensitivity Each receptor has a characteristic sensitivity Receptive Field Area is monitored by a single receptor cell The larger the receptive field the more difficult it is to localize a stimulus Sensory Units Functional units of afferent sensory processing and the include sensory receptors amp receptive field of that receptor Sensory Receptors are classified in a variety of ways including Response Characteristics degree of adaptation Location of Receptors Type of stimulus modality thy they respond to Receptor Potentials a type of graded potential Depolarizing Hyperpolarizing Produced by stimulation of a receptor Proportional to the strength of the stimulus The greater the receptor potential the greater the frequency of nerve impulses sent by the sensory neuron to the CNS Sensory Transduction A possess through which sensory receptors convert stimuli into action potentials Sensory Receptors Stimulation produces receptor potentials followed by the production of action potentials along the axon of a sensory neuron Convey information strength duration and variation of the stimulus detected by varying the frequency of the action potentials produced in the sensory receptor axon frequency coding of sensory information Specialized Neuronal Cells Monitor specific conditions in the body internal environment or external environment Your perception of the nature of that stimulus depends on the path it takes inside the CNS How does the nervous system turn the signal off from the perspective of out ability to perceive information Sensory receptors show adaptation Receptor Adaptation A reduction in sensitivity reduced action potential firing frequency when exposed to a constant stimulus Fastadapting receptors thermoreceptors SIowadapting receptors nociceptors The nervous system quickly adapts to stimuli that are painless amp constant Phasic Receptors Fastadapting receptors Are normally inactive Become active for a short time whenever a change occurs Provide information about the intensity and rate of change of a stimulus Tonic Receptors Slowadapting Receptors Are always active Show little peripheral adaptation Remind you of an injury long after the initial damage has occurred How do we fine tune incoming sensory information Through structural mechanisms receptive field numbers sizes amp their degree of overlap Through neural mechanisms lateral inhibition Tactile Discrimination Determined by the extent of receptive field density includes the numbers size and degree of overlay of the receptive fields high tactile discrimination many small overlapping receptive fields low tactile discrimination fewer large nonoverlapping receptive fields Lateral Inhibition A means through neural mechanisms for creating quotcontrast enhancementquot when trying to localize stimuli in areas of high tactile sensitivity Exteroceptors provide information about the quotexternal environmentquot Proprioceptors Monitor the positions ofjoints and muscles monitor tension in tendons and ligaments via golgi tendon organs Monitor muscular contraction and muscle stretch via muscle spindles The most structurally and functionally complex of general sensory receptors Interoceptors monitor visceral organs and functions internal environment General Senses Describe out Sensitivity to Temperature Pain Touch Pressure Vibration Proprioception Special Senses Olfactionsmell Visionsight Gustationtaste Equilibrium balance Hearing Classifying Sensory Receptors Divided into 4 types by the nature of the stimulus modalityenergy that excites them and include Nociceptors pain Thermoreceptors temperature Mechanoreceptors physical distortion Chemoreceptors chemical concentration Nociceptors Structurally they are free of nerve endings with large Found in the superficial portion of the skin joint capsules bones and around the walls of blood vessels Are sensitive to temperature extremes mechanical damage and dissolved chemicals chemicals released by injured cells Two types of neurons mediate information type C fibers amp myelinated type A fibers Type C Fibers Relay slow pain or burning and aching pain Cause a generalized activation of the reticular formation and thalamus You become aware of the pain but only have a general idea of the area affected Myelinated Type A Fibers Relay fast pain or prickling pain eg an injection or a deep cut Sensations reach the CNS quickly and often trigger somatic reflexes Relayed to the primary sensory cortex and receive conscious a en on Thermoreceptors quottemperature receptorsquot Conducted along the same pathways that carry pain sensation spinothalamic pathway Are free nerve endings located in dermis skeletal muscles liver amp hypothalamus Two types warm amp cold cold receptors out number warm 34 times Mechanoreceptors Sensitive to stimuli that distort their plasma membranes physical stimuli Contain mechanically gated ion channels shoes gates open or close in response to stretching compression twisting amp other distortions of the membrane Three classes tactile receptors proprioceptors amp baroreceptors Tactile Receptors Provide the sensations of touch pressure and vibration Baroreceptors Detect pressure changes in the walls of blood vessels and in portions of the digestive reproductive and urinary tracts Respond immediately to a change in pressure but adapt rapidly Fine Touch amp Pressure Receptors Are extremely sensitive Relatively narrow receptive field Provide detailed information about a source of stimulation Crude Touch and Pressure Receptors Relatively large receptive fields Provide poor localization Give little information about the stimulus Free Nerve Endings Sensitive to touch and pressure Root Hair Plexus Nerve Endings Monitor distortions and movements across the body surface wherever hairs are located Lamellate Corpuscles Pacinian Corpuscles Sensitive to deep pressure Fastadapting receptors Most sensitive to pushing or highfrequency vibrating stimuli Tactile Corpuscles Meissner Corpuscles Fine touch pressure and lowfrequency vibration Rapidly adapting Most abundant in the eyelids lips fingertips nipples and external genitalia Riffing Corpuscles Sensitive to pressure amp distortion of the skin Located in the reticular deep dermis Tonic receptors that show little if any adaptation Tactile Discs Merkel Discs Fine touch and pressure receptors Extremely sensitive tonic receptors Have very small receptive fields Somatic Sensory Pathways Carry sensory information from the skin and musculature of the body wall head neck and limbs Three major somatic sensory pathways Posterior column pathway Spinothalamic pathway Spinocerebellar pathway What happened to somatic sensory afferent information once it has been detected by the primary sensory neurons It is relayed to the CNS via sensory pathways FirstOrder Neuron Somatic Sensory Pathway Sensory neuron delivers sensations to the CNS Cell body of a firstorder general sensory neuron is located in dorsal root ganglion or cranial nerve ganglion SecondOrder Neuron relay neurons Somatic Sensory Pathway Axon of the sensory neuron synapses on an interneuron in the CNS May be located in the spinal cord or brain stem ThirdOrder Neuron Somatic Sensory Pathway If the sensation is to reach our awareness the secondorder neuron synapses on a thirdorder neuron in the thalamus Posterior Dorsal Column Pathway Carries sensation of highly localized quotfinequot touch pressure vibration and proprioception Terminates on the postcentral gyrus of the somatosensory cortex Sensory Homunculus Functional map of the body located on the primary somatosensory codex Distortions occur because Area of sensory cortex devoted to particular body region is not proportional to region39s size but to number of sensory receptors it contains Spinocerebellar Pathway Carries proprioceptive information from skeletal muscles muscle spindles tendons Golgi tendon organs and joints joint capsule receptors Feeling Pain Lateral Spinothalamic Tract Referred Pain Strong visceral pain activates interneurons in the spinothalamic pathway Pain projects to primary sensory cortex doesn39t contain a map of visceral organs result is individual feels pain in specific part of body surface Examples 1 The pain of a heart attack is frequently felt in the left arm 2 The pain of appendicitis is generally felt first in the area around the navel and then in the right lower quadrant Two strategies for pain inhibition include Central pain inhibition amp afferent inhibition gate theory Afferent Pain Inhibition Gate Theory Pain quotslowquot type carried by Type C unmyelinated fibers can be quotover riddenquot by afferent sensory information carried via Type A fibers myelinated Central Pain Inhibition The transmission of afferent incoming nociceptive information can be inhibited by quotdescendingquot efferent modulation by the release of endogenous opioid neuropeptides eg enkephalins endorphins Phantom Limb Pain Often experienced by individuals who have had a limb amputated The causes were initially thought to be due to irritation at the damaged end of the nerves We now know that the causes are more complex involve higher levels sensoryassociation areas Much of our current understanding of the complexities of phantom limb pain are as a result of the work of V Ramachandran FirstOrder Neurons Posterior Column Pathway Enter the spinal cord and ascend via the fasciculus gracilis and fasciculus cuneatus tracts where they synapse with 2nd order neurons in the medulla oblongata SecondOrder Neuron Posterior Column Pathway Cross to the opposite side of the medulla and ascend to the thalamus where they synapse with thirdorder neurons ThirdOrder Neurons Posterior Column Pathway Project information to the primary sensory cortex postcentral gyrus of the parietal lobe FirstOrder Neurons Spinocerebellar Pathway Enter the spinal cord and synapse on interneurons in dorsal gray horn of the spinal cord SecondOrder Neuron Spinocerebellar Pathway Ascend in either the posterior or anterior spinocerebellar tracts Third Order Neuron Spinocerebellar Pathway Synapse with Purkinje neurons in the cerebellar cortex Spinothalamic Pathway Provides conscious sensations of poorly localized quotcrudequot touch pressure pain and temperature FirstOrder Neurons Spinothalamic pathway Synapse with 2nd order neurons in gray horns of spinal cord SecondOrder Neuron spinothalamic pathway Cross to the opposite side of the spinal cord and ascend within the anterior or lateral spinothalamic tracts the anterior tracts crude touch and pressure the lateral tracts pain and temperature ThirdOrder Neuron spinothalamic pathway Synapse in ventral nucleus group of the thalamus After the sensations have been sorted and processed they are relayed to primary sensory cortex Chapter 17 Five Special Senses Olfaction Gustation Vision Equilibrium Hea ng What distinguishes the five special senses from somatic senses The receptors for the special senses are housed in specialized organs instead of being dispersed throughout the body information from them is carried by special afferents as opposed to general somatic and visceral afferents Where are the olfactory organs located Within the olfactory epithelium in nasal cavity On either side of the nasal septum Inferior surface of cibriform plate and superior nasal cochae see fig 173 What type of cells make up the two layers of the olfactory organs Olfactory Epithelium Lamina Propia Olfactory Epithelium One of two layers of the olfactory organs Olfactory receptor neurons chemoreceptors Basal cells stem cells that replace olfactory receptors every 60 days Supporting cells simple columnar epithelium Basal cells Olfactory stem cells that replace receptors every 60 days Lamina Propia One of two layers of the olfactory organs contains olfactory glands that secrete mucus Olfactory Receptor Cells Highly modified bipolar neurons Apart of the olfactory epithelium detect dissolved chemicals interacting with odarantbinding proteins humans have gt900 different odorant binding proteins How can humans distinguish 4000 different odors if we only have 900 different genes encolding odorantbinding proteins Olfactory epithelium contains receptor populations with distinct sensitivities The CNS interprets each smell on the basis of overall pattern of receptor activity Central Adaptation Ensures that you quickly lose awareness to a smell that you have been exposed to for some timebut retain sensitivity to others Olfactory Signal Transduction Pathway Odorant bind to receptors in dendrites Binding activates Gprotein coupled receptor GProtein coupled receptor activates adenylate cyclase to simulate cAMP production cAMP binds to sodium channels causing their opening and membrane depolarization Axons leaving the olfactory epithelium collect into bundles of 20 or more and synapse in the olfactory bulb Axons leave the olfactory bulb via the olfactory tract From there the signal reaches the olfactory cortex temporal lobe of the cerebrum and hypothalamus parts of the limbic system which elicit emotionalmemory response to odors What is unique about olfaction as compared to other special senses does not synapse in the thalamus Special senses that transmit info to hypothalamus and limbic system Func onalconsequences Olfaction Gustation Elicit emotional responses memories can also trigger reflexes such as stimulating digestive activity Special senses that have stem cells for continual replacement of damaged receptors Both olfaction and gustation contain Basal Cells Water Receptors Associated with pharynx and circumvallate papillae Lingual Papillae also how many taste buds each and location Specific epithelial projections of superior tongue where taste buds cluster 3 types Filiform Papillae no taste buds Purpose is to provide friction towards front of tongue Fungiform Papillae 5 taste buds each middle of tongue Circumvallate Papillae 100 taste bus each back of tongue 4 primary tastes and 2 additional primary sweet sugars alcohols some amino acids salty bitter alkaloids sour acids additional umamisavory free glutamates water receptor Umami Savory taste Detect free glutamates important because these are the most abundant amino acids in our bodies Gustatory Transduction differences in tastes Salt and sour Activate chemically gated ion channels resulting in cell depolarization sweet bitter and umami Activate Gprotein gustducins coupled receptors Gustation signaling pathway Information is passed from medulla oblongata to the thalamus for screening Sensory afferents synapse in the thalamus then routed to Gustatory cortex in the insula of the cerebrum and Hypothalamus and limbic system to elicit emotional reaction to taste Lacrimal Caruncle Associated with eyelids Contain sebaceous and sudoriferous glands that produce secretions to lubricate the eye surface Tarsal Glands Associated with eyelashes Modified sebaceous glands that produce oily secretion to prevent lid stickings Conjunctiva Transparent mucous membrane Covers anterior surface of eye and interior surface of lids Produces lubricating mucus to keep eyes moist Contains tiny capilaries Lacrimal Apparatus Lateral and superior to eye Produces lacrimal fluid to cleanse and protect eye surface Lacrimal fluid contains Mucus lubrication Antibodies immune defense against microbes Lysozyme enzyme that lyses bacteria Palpebrae eyeHds continuation of skin Palpebral fissure gap that separates upper and lower palpebrae Canthus where eyelids connect Lacrimal Canaliculi Where lacrimal fluid is collected medial corner of eye 3 layers of the wall of the eye Outer Fibrous Tunic Intermediate Vascular Tunic lnner Neural Tunic Fibrous Tunic Outer layer of the wall of eye Avascular dense fibrous connective tissue includes Sclera white of eye Cornea Sclera White of the eye Posterior 56ths Function maintain eye shape attachment of eye muscles Continuous with epineurium of optic nerve Cornea Anterior 16 Clear allows light to enter eye high concentration of pain receptors Damagescaring inhibit vision Corneal transplants No tissue match required Vascular Tunic Uvea Middle layer of wall of eye Route for blood vessels and lymphatic vessels Regulates amount of light entering eye Secretes and reabsorbs humor that circulates within chamber of eye Controls shape of lens Components lris Ciliary Body The Choroid Iris Anterior portion of uvea Contains Papillary constrictor muscles Consists of smooth muscle elastic fibers Eye color determined by melanin density and distrubution Parasympathetic stimulation Pupillary constrictor muscles Series of concentric circles around the pupil Used to decrease pupil diameter Sympathetic stimulation pupillary dilator muscles Extend radially away from edge of pupil lncrease pupil diameter Ciliary Body Contain ciliary processes and muscles that attach to suspensory ligaments of lens circular smooth muscles function to focus lens and center it posterior to pupil Secretes fluid that fills anterior of eye Choroid Vascular layer Separates fibrous and neural tunics Contains melanocytes to prevent light scatter melanocytes Component of the Choroid Prevent light scatter Neural Tunic lnner layer of wall of eye Pigmented part thin outer Neural partinner retina Pigmented Part Portion of Neural tunic Melaninrich simple cuboidal epithelium Absorbs light to prevent visual echos stores vitamin A Neural Part Part of Neural Tunic Contains visual receptors Rods and Cones and associated Neurons Rod Photoreceptors Do not discriminate colors but are highly sensitive to light Long and slender Respond to almost any photon 130 million Around periphery of retina As you move towards the center of the retina the density of rods gradually increase Undergo extensive convergence in retina vision is grainy and blurry Cone Photoreceptors Provide color vision 3 types Densely clustered in fovea center of macula lutea short and tapered 6 million concentrated at macula Show little convergence to their ganglion cells P cells Bipolar cells Within Retina Transmit info from rods cones also synapse with ganglion cells Horizontal Cells Involved in visual processing Extend across outer portion of retina Synapse with photoreceptors and bipolar cells modulate communication between photoreceptors and ganglion cells thereby altering sensitivity Amacrine Cells Comparable to horizontal cell layer Found where bipolar cells synapse with ganglion cells modulate communication between photoreceptors and ganglion cells thereby altering sensitivity Ganglion Cells Transmit visual information to brain axons exit eye as optic optic nerve Optic disc blind spot circular region just medial to fovea where axons bundle to form the optic nerve Scotomas Abnormal blind spots outside of region of the optic disc damage Macula Lutea Focal point directly behind center of lens Contains most of the cones of the retina Foveacen a s Center of Macula cones only Posterior Cavity Posterior to lens Filled with vitreous humor Func ons Support retina in contact with choroid while allowing light to pass Provide lntraocular pressure to counteract extrinsic eye muscles Vitreous humor Clear gel formed in embryo Maintained throughout life Fills Posterior eye cavity Anterior Cavity Anterior to lens Filled with Aqueous Humor Aqueous Humor Diffuses through both cavities Reabsorbed at the canal of Schlemm at base of iris Func on Maintain consistent intraocular pressure Diffusion medium for lens and cornea Canal of Schlemm At base of iris Reabsorbs Aqueous humor Glaucoma Failure to drain aqueous humor Pressure compresses retina and optic nerve resulting in vision loss The Lens Transparent flexible avascular disc Cells have no organelles Cells contain crystallin proteins that last a lifetime Held in place directly behind pupil by suspensory ligaments which attaches lens to ciliary body Cataract Clouding of the lens due to clumping of crystallins Structures that refract light Cornea lens humors Accomodation Shape of lens changes to focus image on retina Mediated by Parasympathetic system Distant objects lens is flattened Close objects lens shape becomes more rounded Myopia nearsightedness Focal point is in front of retina Cannot focus on distant objects Corrected with concave lens Hyperopia Focal point is behind retina Cannot focus on close objects Corrected with convex lens Presbyopia Agerelated loss in near vision accommodation Due to decrease in lens elasticity Corrected with reading glasses Astigmatism Unequal curvature of cornea or lens Part out of focus part in focus Visual Acuity Level of detail seen at a distance of 20ft A person standing at 20ft with 20x vision would have the visual acuity of a normal person at x feet 2020 normal 20l15 Person standing at 20ft can see what normal people can see at 15ft 20l200 legally blind Signal Transduction Pathway for Photoreception A rhodopsin molecule binds a photon Retinal is isomerized from 11cis to 11trans activating and releasing opsin Opsin activates the GProtein transducin Transducin activates phosphodiesterase PDE PDE breaks down cGMP which CLOSES Na channels This reduces the dark current This reduces neurotransmitter release and hyperpolarizes the receptor The change in activity is relayed to bipolar cells to ganglion cells and down the optic nerve to 1 Suprachiasmatic Nucleus circadian rhythm 2 Superior colliculus visual reflex 3 Primary visual cortex Bleaching After absorbing a photon the rhodopsin molecule begins to break down into retinal and opsin Optic Radiation Bundle of projection fibers linking lateral geniculate with visual cortex External Ear Auricle pinna External acoustic meatus Tympanic membrane Auricle pinna Surrounds entrance to external acousitc meatus Protects opening of canal Funnels sound and provides directional sensitivity External acoustic Meatus Ends at tympanic membrane Lined with hairs and ceruminous glands Tympanic membrane Thin semitransparent sheet of connective tissue and epithelium The middle ear tympanic cavity Airfilled mucosalined chamber between tympanic membrane and oval window Encloses three auditory Ossicles Malleus lncus Stapes Auditory ossicles Malleus lncus Stapes Amplify and transmit sound energy from tympanic membrane to oval window Tensor tympani and stapedius muscles Protect ears from loud sounds by inhibiting vibrations of tympanic and oval windows Innerear located in temporal bone posterior to eye consists of network of fluid fluid filled chambers Fluid functions to transit sound or movement energy to mechanorecptor cells Vestibule gravity and acceleration Semicircular Canals rotation Cochlea sound Vestibule gravity and acceleration Component of inner ear Membranous sacs saccule and utricle Semicircular Canals rotation 3 in total xyz planes Connected to vestibule Filled with endolymph are semicircular ducts and semicircular canals the same Each duct contains Ampulla with gelatinous cupula Stereocilia resemble long microvilli on the surface of hair cells Kinocilium Single large cilium Endolymph Liquid in Semircular canals Cochlea Sound Spiral conical chamber begins at oval window contains organ of corti filled with perilymph Perilymph Liquid in cochlea Hair Cells Basic receptors of inner ear Provide info about direction and strength of mechanical stimuli Utricle and Saccule Provide Equilibrium Sensations Connected with endolymphatic duct which ends in endolymphatic sac Maculae Oval structures where hair cells cluster Statoconia Densely packed calcium carbonate crystals on surface of gelatinous mass Makes up Otolith ear stone When head is level statoconia39s weigh presses on macular surface pushing the hair cell processes down When head is tilted the pull of gravity on the statoconia shifts them to the side thereby distorting the hair cell processes Otolth Ear stone Gelatinous matrix and statoconia Vestibular Receptors Active sensory neurons of vestibular ganglia Axons form vestibular branch of vestibulocochlear nerve Synapse within vestibular nuclei Four Functions of Vestibular Nuclei 1 Integrate sensory info about balance from both sides of head 2 Relay info from vestibular complex to cerebellum 3 Relay info from vestibular complex to cerebral cortex 4 Send commands to motor nuclei in brain stem and spinal cord Stereocilia Within semicircular ducts Resemble long microvilli Are on surface of hair cells Kinocilium within semicircular ducts Single large cilium What sensory information is encoded for by hair cells in the semicircular ducts Provide information about direction and strength of mechanical stimuli Ampulla An expanded region of the semicircular ducts which contains sensory receptors Contains a region in the wall called the Crista Region in the ampulla that contains the receptors hair cells Crista Region in the ampulla that contains the receptors Each crista is bound to a cupua Gelataneous structure which extends the full width of the ampulla Cupula Gelatanious structure which extends the full width of the ampulla During head rotation movement of endolymph along the side of the semicircular duct pushes cupula to the side and distorts the receptor process Movement of fluid in one direction stimulates the hair cells stereocilia displaced toward kinocilium Movement of Endolymph stimulates hair cells in one direction and inhibits hair cells in the other direction When stereocilia are displaced toward kinocilium Hair cells stimulated When stereocilia are displaced away from kinocilium Hair cells inhibited General Mechanism of Hearing Sound waves in the air enter the external auditory canal Vibrate the tympanic membrane This in turn vibrates the malleus incus and stapes This creates pressure waves through the oval window into the perilymph of the scala vestibuli of the cochlea Pressure waves distort the basilar membrane on their way to the round window of the scala tympani causing hair cell cilia to brush against the tectorial membrane and become distorted Flexion of the stereocilia opens ion channels causing depolarization of stimulated hair cells An EPSP is transmitted to the sensory neurons of the spiral gangHon Axons of the spiral ganglion transmit action potentials along the vestibulocochlear nerve to be diverged to the inferior colliluli of the mesencephalon to initiate auditory reflexes to the thalamus for screening and routing to the auditory cortex in the temporal lobe of the cerebrum for interpretation Pitch Determined by region of basilar membrane vibrated Low frequency sounds travel further into the cochlea APEX High frequency sounds stimulate Base Volume Volume is determined by the number of hair cells stimulated High volume stimulates more hair cells Effects of Aging on the Ear Tympanic membrane gets less flexible Articulations between ossicles stiffens Round window may begin to ossify
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'