EXAM 3 CH 12-16

loss of declarative memory

Amnesia

Neuroglia of CNS 1) Oligodendrocytes, some what resemble an octopus, each arm reaches out to a nerve fiber and spirals around it like electrical tape wrapped repeatedly around a wire. 2) Ependymal cells, line cavities of brain and spinal cord and secrete circulate CSF 3)Microglia, Phagocytize and destroy microorganisms, foreign matter, and dead nervous tissue Neuroglia of PNS 1) Schwann cells, form neurilemma around all PNS nerve fibers and myelin around most of them, aid in regeneration of damages nerve fibers 2) Satellite cells, surround somas of neurons in the ganglia, provide electrical insulation and regulate chemical environment of neurons

Anatomical structures of a neuroglia, and the hierarchy of complexity?

means cannot form new memories

Anterograde

electrical and chemical cell to cell communication

Big picture function of nervous system?

protect the neurons and help them function

Big picture function of neuroglia,(glial cells)

Sensory stimuli- term for all of the features about our external and internal environment the human body can detect, takes many forms, light, mechanical, chemical etc. Sensory receptors and sense organs- structures specialized to detect sensory stimuli, sensory receptors are simple and are usually attached to the end of a unipolar nerve. sense organs are more complex structures such as eyes and ears Transduction and receptor (local) potentials, convert the physical form of the stimulus into electricity, specifically into something called a receptor potential( same as other local potentials) Sensation, what we experience the end result of detecting and becoming aware of sensory stimuli

Big picture function of sensation

Bundle of axons traveling together in the PNS, spinal and cranial nerves, to carry information to and from the spinal cord and body.

Big picture function of spinal nerves?

Regulates the activity of all organ systems, regulation is unconscious

Big picture function of the autonomic nervous system.

Is in the inferior cervical region, gives rise to nerves of the upper limbs.

Cervical enlargment?

Unmyelinated axons- simple signal conduction, has voltage gated channels along its entire length. When an action potential occurs the speed for an unmyelinated fiber is slow but does not get weaker with distance(nondecremental) Myelinated axons- voltage gated channels are not as common, the myelin insulates the fiber from the EFC. Speeds up conduction by it seals the nerve fiber and increases its resistance to a leakage of Na+ out of the axon. It also creates a greater separation between the ICF and ECF, making cations and anions less attracted to each other, letting them move more freely in the axon, transferring energy to one another.

Compare and contrast action potential conduction in unmyelinated and myelinated axons.

Sympathetic adapts the body for physical activity. Increases heart rate, alertness, blood pressure, and pulmonary airflow. Responds as the flight or fight response Parasympathetic has a calming affect on body functions, often called the resting and digesting state.

Compare and contrast the functions of sympathetic and parasympathetic divisions of the autonomic nervous system.

Electrical synapses -gap junctions and ions, cannot make decisions but can transfer information Chemical synapses -synaptic cleft and neurotransmitters, can make decisions and transfer information

Compare and contrast the structure and function of electrical and chemical synapses.

Neurons respond to stimuli by producing electrical signals that are quickly conducted to other cells at distant locations.

Conductivity define.

Stimulus and sensory receptors- free nerve endings in a body part initiate a stimulus in response to a sharp pain or excessive heat. Reflex arc- the afferent neuron sends the pain of heat information to the opposite side of the spinal cord where it is relayed be an interneuron to an efferent neuron. Response- the efferent neuron causes extensor muscle on the opposite side of the body to contract. Their contraction supports the body while the side that was hurt is flexing to escape the stimulus. Thus, the crossed extensor reflex helps you to retain balance as the body is "dancing" away from the pain or heat.

Crossed extension reflex helps with the withdrawal reflex

descriptive memory

Declarative memory

Arises from the brainstem at the foramen magnum of the skull, passes through the vertebral canal as far as the inferior margin of the first lumbar vertebra (L1) or slightly beyond. In adults it averages about 45cm long and 1.8cm thick (about as thick as a pinky finger)

Describe the location of the spinal cord within the vertebral column in an adult.

Absolute refractory period- where no stimulus of any strength will trigger a new action potential Relative refractory period- it is possible to trigger a new action potential, but must be an unusually strong stimulus

Difference in absolute refractory period and the relative refractory period?

cells and organs that respond to motor division signals

Effectors are what?

All cells are excitable, they respond to environmental changes (stimuli), neurons exhibit this property to the highest degree.

Excitability define.

When a chemical (ligand) binds to a receptor on the neuron, the receptor acts as a ligand-gated channel that opens and allows Na+ to diffuse into the cell, this depolarizes the plasma membrane.

Excitatory local potential.

Somatotopy, body map not based on physical size of body part, but on the importance of the information and the amount of information the gyrus receives from the somatic sensory cortex

Explain how somatic sensation is mapped within the postcentral gyrus.

1) Action potentials are all or nothing, none graded, a stronger stimuli will not trigger a stronger action potential 2) Nondecremental, they do not get weaker with distance. The last action potential is as strong as the first no matter how far. 3) Irreversible, if a neuron reaches threshold, the action potential goes until its complete, it cannot be stopped once it has begun.

Explain how the three properties of an action potential are used to transfer information.

Voluntary movement of skeletal muscle is mapped first with the somatic sensory cortex which receives sensations from the bones, joints, skin, and then skeletal muscles, which get contracted.

Explain how voluntary movement of skeletal muscles is mapped within the precentral gyrus.

Multipolar 1)dendrites- electricity is called a local potential, collects information and transfers it to the cell body 2)cell body- elecrticity is called a local potential, it makes decisions and transfers decisions to axon 3)Axon and terminal arborization- electricity is called an action potential, does not make decisions, transfers decision of cell body to the synaptic knob 4)Synapse- electricity is called synaptic activity, transfers decision of cell body to another neuron or to a cell body in the body, may provide some input to the decision of the cell body

Explain the big picture process of information transfer in a multipolar.

1) sensory receptors, electricity is called a local potential, makes decisions, transfers decisions to peripheral fiber 2)Peripheral fiber- electricity is called an action potential, does not make decisions, transfers decision of sensory receptors to the central fibers 3) central fiber and terminal arborization- electricity is called an action potential, does not make decisions, transfers action potential from peripheral fiber to the synapse 4) Synapse- electricity is called synaptic activity, transfers decision of cell body to another neuron, may provide some input to the decision of the cell body

Explain the big picture process of information transfer in a unipolar neuron.

When the local current arrives at the axon hillock, it depolarizes the membrane at that point which appears as a steadily rising local potential, for anything more to happen, this local potential must rise to a critical voltage called the threshold(-55mV, the minimum needed to open a voltage gated channel). The neuron then fires, or produces and action potential.

Explain the relationship between the local potential and threshold for firing an action potential.

1) arrival of a nerve signal at the synaptic knob opens voltage gated calcium channels 2) Ca2+ enters the know and triggers exocytosis of the synaptic vesicles, releasing ACh. 3) Empty vesticles drop back into the cytoplasm to be refilled with ACh, while vesicles in the reserve pool move to the active sites and release their ACh. 4) ACh then diffuses across the synaptic cleft and binds to ligand-gated channels on the postsynaptic neuron. These channels open, allowing Na+ to enter the cell and K+ to leave. (remember Na+ and K+ pass in opposite directions through the same gates) 5) As Na+ enters, it spreads along the inside of the plasma membrane and depolarizes it, producing a local voltage shift called postsynaptic potential. Like other local potentials, if this is strong and persistent enough, it opens voltage gated ion channels in the trigger zone and causes the postsynaptic neuron to fire.

Explain the steps in the process of excitatory cholinergic synapse.

An electrical potential is the difference in the concentration of charges particles between one point and another. It is a form of potential energy that could product a current. The amount of the charges separation can be measured (voltage, which is the information, meaning smaller voltages, less info) An electrical current is a flow of charged particles from one point to another. Ions move through the plasma (cell) membrane to relocate to the ICF or ECF (changes the charge separation, changes the voltage, changes the info!)

Explain the structure and function of electrical potentials and electrical currents in neurons.

A term used to to describe the PNS (peripheral nervous system). It is a network of 43 pairs of motor and sensory that connect the brain and spinal cord to the entire body.(branch of nerve plexus)

Explain what a peripheral nerve is.

Reflexes require stimulation, they are not spontaneous actions but responses to sensory input. Reflexes are quick, they generally involve few interneurons or none and minimum synaptic delay Reflexes are involuntary, they ovvus without intent, often without our awareness, difficult to suppress. Reflexes are stereotypes, they occur in essentially the same way every time, predictable, unlike voluntary movement.

Explain what a reflex is and the four properties of reflexes.

AKA EEG- is a machine that records from electrodes on the forehead and scalp. It monitors electrical activity in the brain (brain waves)

Explain what an electroencephalogram is.

these are reflexes of skeletal muscles, involve the somatic nervous system

Explain what somatic reflex is.

A local potential codes the features of the transduced sensory stimulus

Explain what the function of a receptor (local) potential is.

PNS are vunerable to cuts, crushing and injuries and other traumas, because the CNS is protected by the skull and vertebral column

Explain why PNS nerve fibers are more susceptible to trauma than CNS nerve fibers.

Some nerve fibers connect to the wrong muscle fibers or never find a muscle fiber at all, and some damaged motor neurons simply die.

Explain why functional deficits are often present after nerve fiber regeneration.

Axodendritic synapse- is presynaptic Axosomatic synapse- presynaptic Axoaxonic synapse- postsynaptic

For each of the 3 main types of synapses, list which structures in the pre- and post-synaptic neuron form the synapse.

1) Acetycholine 2) Amino acids 3) Monoamines 4) Neuropeptides

Four main categories of neurotransmitters

Modality- type of sensation Location- where sensory stimulus is coming from (external to body/ internal to body), receptive field (very small, fine discrimination/ very large, poor discrimination) Intensity- strength of the sensory stimulus Duration- how long the sensory stimulus lasts, sensory adaptation (for some sensations, as a duration increases, the ability to be aware of the stimulus decreases, keeps us from sensory overload)

Four types of information sensory receptors can collect about sensations.

carries out the communication

Function of a neuron?

A spiral layer of insulation around a nerve fiber is formed by oligodendrocytes in the CNS. They wrap around the axons of multiple neurons, here the myelin spirals inward toward the axon as it is laid down. A Schwann cell of the PNS, wraps around an axon repeatedly to form a multiayered myelin sheath.

How do oligodendrocytes and Schwann cells form the myelin sheath around axons in the CNS and PNS?

1) graded- vary in size, the stronger the stimulus, the larger the local potential 2)decremental- decrease in size the farther they get away from the site of stimulation 3)reversible- stop when the stimulus stops 4)excitatory- makes the resting membrane potential less negative, move towards zero(depolarizes, causes a behavior) EXTRA 5)inhibitory- makes the resting membrane potential more negative, move away from zero(hyperpolarization, stops/prevents a behavior)

How four properties of a local potential are used to code information?

-diffuses away -taken up by synaptic knob -killed by an enzyme

How is synaptic transmission terminated?

Employs aminobutyric acis (GABA) as its neurotransmitter. Amino acid neurotransmitters work by the same mechanism as ACh, binding to ion channels and causing immediate changes in the membrane potential. The GABA receptor, however, if a chloride channel, when it opens Cl- enters the cell and makes the inside more negative than the resting membrane potential, thus the neuron is inhibited or less likely to fire.

Inhibitory GABA-ergic synapse

Afferent fibers- carry sensory signals from receptors to the CNS Efferent fibers- carry motor signals from the CNS to effectors Somatic fibers- innervate skin, skeletal muscles, bones, and joints Visceral fibers- innervate blood vessels, glands, and viscera

List the functions of the four main classes of axons (fibers)

8 Cervical 12 Thoracic 5 Lumbar 5 Sacral 1 Coccygeal

List the number of spinal nerves associated with each spinal cord region.

Mixed- afferent and efferent, somatic and/or visceral Sensory- afferent only, somatic and/or viscerl Motor- efferent only, somatic and/or visercal

List types of axons found in mixes, sensory, and motor nerves.

Long term memories are formed in the cerebral cortex from short term memories in the hippocampus. Short term memories can become long term through the process of consolidation, involving rehearsal and meaningful association.

Long term memories

Is in the lumbosacral region, it issues nerves to the pelvic region and lower limbs.

Lumbar enlargment?

Inferior to the lumbar enlargment, the cord tapers to a point. The medullary cone is a bundle of nerve roots that occupy the vertebral canal from L2 to S5. This bundle resembles a horses tail and innervates the pelvic organs and lower limbs. (Cauda quina)

Medullary cone and Cauda equina?

carries signals from the CNS to gland and muscle cells that carry out body's responses.

Motor (efferent) division does what?

1)Anterior ramus- innervates the anterior and lateral skin and muscles of the trunk and gives rise to the nerves of the limbs 2)posterior ramus- innervates the muscles and joint in that region of the spine and the skin of the back 3)a small meningeal branch- reenters the vertebral canal and innervates the meninges, vertebrae, and spinal ligaments with sensory and motor fibers. 4)communicating rami- branched off from the anterior rami and are components of the sympathetic nervous system

Name four rami banches of the spinal nerve and list their functions.

1) cervical- innervates ear, jar, neck, anterior side of chest 2) brachial- innervates shoulders, arms, and hands 3) lumbar- innervates abdominal and gluteal regions, hips, thighs, and knees 4&5) sacral and coccygeal- innervate gluteal region, perineum, thighs, knees, lower legs, and feet

Name the five nerve plexuses and list the parts of the body they innervate.

Alpha waves, beta, theta, delta and sleep spindle

Name the four main types of brain waves.

Stimulus modality -Thermoreceptors (temperature stimuli) -Photoreceptors (light stimuli) -Nociceptors(pain stimuli) -Chemoreceptors(chemical stimuli) -Mechanoreceptors(physical stimuli)

Names and functions of specific types of sensory receptors.

Parasympathetic, ACh in pre and ACh in post Sympathetic adreneric fiber pre-ACh post-NE Sympathetic cholinergic fiber pre-ACh post- ACh

Neurotransmitters that are used by the pre- and post- ganglionic neurons of the sympathetic and parasympathetic divisions.

calms the body (slows heart rate but stimulates digestion)

Parasympathetic division does what?

cell bodies -> preganglionic fibers (long) ->genglionic neurons -> short postganglionic fibers-> viscera

Parasympathetic division pathway

1) somatic receptors in skin, muscles, and tendons 2)afferent nerve fibers, carry information from the receptors to the posterior horn of the spinal cord or to the brainstem 3) an intergrating center, a point of synaptic contact between neurons in the gray matter of the cord or brainstem 4)efferent nerve fibers, which carry out the response 5)effectors, the muscles that carry out the response.

Pathway of somatic reflex arc.

remembering how to do something step by step

Procedural memory

Broca's area- in frontal lobe, creates motor plan for speech Primary motor cortex- in precentral gyrus of frontal lobe, carries out motor plan like which muscles will be used and when Occipital lobe- receiving language, seeing language, primary visual cortex Temporal lobe, hearing language, primary auditory cortex Parietal lobe, touch, primary secondary cortex in postcentral gyrus (no understand of language) Wernicke's area in temporal lobe, understands spoken and written language, creates a speech plan (what you say and how to say it) Angular gyrus, creates a writing plan, located in parietal lobe

Recall the brain regions which mediate each of the aspects of receiving, comprehending, and expressing language.

The soma and some neurilemma must remain to regenerate.

Recall the condition required for PNS nerve fiber to regenerate.

The divisions divide into the sensory and motor division, and from the motor division splits into visceral motor division and somatic motor division. The visceral division splits into the sympathetic and parasympathetic divisions. The peripheral nervous system is

Recall which division of the peripheral nervous system the autonomic nervous system is.

PNS can regenerate but CNS cannot.

Recall which nerve fibers can and cannot regenerate.

Occurs in all structures in all neurons, it is the point of nothing, taking a break from movement, no information transfers during this time. But it also means be on alert to do something, get ready to transfer information.

Resting membrane potential, what is it?

means loss of previous memories but can form new ones

Retrograde

When the signal reaches the end of a nerve fiber, the neuron secretes a neurotransmitter that crosses the gap and stimulates the next cell.

Secretion define.

carries signals from receptors

Sensory (afferent) division does what?

carries signals to the skeletal muscles

Somatic motor division does what?

carries signals from receptors (skin, muscles, bones, joints)

Somatic sensory division does what?

1) Local current arrives at axon hillock, depolarizes membrane. (looks as a steadily rising local potential) 2)Local potential must rise to a critical voltage (threshold, -55mV) in order to open voltage gated channels. 3)Neuron fires (action potential) At threshold, voltage gated Na+ opens quickly, while K+ opens slowly. 4)As the rising potential passes 0 mV, Na+ channels are inactivated and begin closing. By the time they are closed, and Na+ inflow stops, the voltage peaks at +35mV. Membrane is now positive on the inside and negative on the outside. 5)Also at the peak of the voltage, the slow K+ channels are fully open. Potassium ions, repelled by the positive ICF, now exit the cell. Their outflow repolarizes the membrane. (voltage shifts back to negative) 6) Potassium channels stay open longer than Na+, so slightly more K+ leaves the cell than the amount of Na+ entered. The membrane voltage drops to 1-2 mV more negative than the original RMP, producing a negative overshoot called hyperpolarization. 7) Na+ and K+ switch places across the membrane during an action potential. During hyperpolarization, Na+ diffusion into the cell and the removal of extracellular K+ by astrocytes gradually restore the original RMP -70mV.

Steps in action potential

Stimulus and sensory receptor, a skeletal muscle is stretched, and the stretch stimulus is detected by a specialized sensory receptor i that muscle called a muscle spindle Reflex arc- the stretch stimulus information is carried by and afferent neuron directly to an efferent neuron in the spinal cord. This reflex DOES NOT require an interneuron in the spinal cord. The afferent neuron synapses directly on the efferent neuron. Response- the muscle which was stretched contracts to counteract the stretching. The response also includes reciprocal inhibition: and interneuron is activated which INHIBITS the efferent neuron which would originally contract the antagonist muscle. knee-jerk is a stretch reflex

Stretch reflex maintains balance and posture

stimulates the body(increasing heart rate and respiratory flow)

Sympathetic division does what?

cell bodies-> short preganglionic fibers-> autonomic ganglion->long postganglionic fibers and epinephrine hormone (adreniline)->visera

Sympathetic division pathway

Transferring information from the axon of a first neuron to the second neuron or to a cell body.

Synapses, big picture function?

Stimulus and sensory receptor- tendon organs are receptors located in tendons, they detect overstretch of tendons. reflex arc- the overstretch information is carried by an afferent neuron to the spinal cord where it is relayed by an inhibitory interneuron to an efferent neuron. Response- the efferent neuron is inhibited causing the muscle associated with the tendon to relax to counteract the overstretch.

Tendon reflex keeps tendons from overstretching.

Stimulus and sensory receptor- free nerve endings in a body part initiate a stimulus in response to a sharp pain or excessive hear. Reflex arc- the pain or heat information is carried by the afferent neuron to the spinal cord where it is relayed by an interneuron to and efferent neuron Response- the efferent neuron causes flexor muscles to contract pulling away from the painful or hot stimulus. The response also includes reciprocal inhibition: a second interneuron is activated which INHIBITS the efferent neuron that would ordinarily contract the antagonist muscle.

The flexor (withdrawal) reflex helps the body escape painful stimuli.

1) Sensory (afferent) neurons, are specialized to detect stimuli such as light, heat, pressures, and chemicals, and transmit info about them to CNS. 2) Interneurons (association neurons) lie entirely within the CNS. They receive signals from many other neurons and carry out the integrative function of the nervous system. They process, store, and retrieve info and make decisions that determine how the body responds to stimuli. 3) Motor (efferent) neurons, send signals predominantly to muscle and gland cells, (the effectors) They are called motor neurons because most of them lead to muscle cells and efferent neurons to signify singal conduction away from CNS

Three functional classes of neurons.

Neural integration( integrates inputs from brain and body to connect them) Locomotion Reflexes

Three main functions of the spinal cord?

1) Sense organs and simple nerve endings receieve info about changes in bodyand external environment and transmits messages to the CNS 2)CNS processes this info and determines what response, if it responds, and the appropriate response 3)CNS tissues commands primarily the muscle and gland to carry out responses

Three step process the nervous system uses to carry out its big picture function?

Two factors are the diameter of the fiber and the presence or absence of myelin. Conduction occurs along the surface of a fiber, large fibers have more surface area and conduct signals more rapidly than small fibers. Myelin further speeds signal conduction. Conduction speed must vary because if it was all fast, the nervous system would be bulky and limited. Smaller nerve fibers and unmyelinated fibers make it possible for things like secretion of stomach acid or dilating the pupil. Where as larger fibers help with movement of skeletal muscles and sensory signals for vision and balance.

Two factors which increase conduction speed in axons, and explain why conduction speed needs to vary.

AKA autonomic nervous system, carries signals to glands, cardiac muscle, and smooth muscle. Involuntary control of these things.

Visceral motor division does what?

carries signals mainly from the viscera of the thoracic and abdominal cavities ( heart, lings, stomach, and bladder)

Visceral sensory division does what?

1) CNS, brain and spinal cord (send the messages) 2)PNS, consists of all the rest (carry out the messages)

What are the anatomical subdivisions of the NS and what are the functions?

A neurotransmitter is a small molecule released from a synaptic vesicle, that diffuses across the synaptic cleft to bind to a receptor. The type of neurotransmitter receptor determines the type of local potential created.

What is a neurotransmitter?

a vertebrae that supplies a pair of nerves. There are 31 segments defined by 31 spinal nerves. 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, and 1 coccygeal nerve.

What is a spinal cord segment?

Schwann cell

Which glial cell makes myelin for axons in the PNS?

multipolar

Which type of neuron has many dendrites and one axon?

Each cerebral cortex specializes in a common set of functions. Left does certain functions, right does certain functions. Left-language, analyzes. Right- insight, creativity, imagination, big picture

recall the functions associated with the categorical and representational cerebral hemispheres. Also recall the associations between handedness and cerebral lateralization(or the difference in functions)

Cognition is the range of mental processes by which we acquire and use knowledge--sensory perception, thought, reasoning, judgment, memory, imagination, and intuition. Such functions are widely distributed over regions of the cerebral cortex.

recall the functions of the association area in cerebral cortex.