A&P Neurons

list the channels and pumps that are located along the entire neuron, and identify the general function of each: transmissive segment

-Voltage gated Ca2+ channels --moves Ca2+ into knob -Ca2+ pumps-- Ca2+ pumped out of knobs -Na+/K+ exchange pump -Na+ leak channels -K+ leak channels

list the channels and pumps that are located along the entire neuron, and identify the general function of each: conductive segment

-Voltage gated Na+ channels -Voltage gated K+ channels -Na+/K+ exchange pump -Na+ leak channels -K+ leak channels

list the channels and pumps that are located along the entire neuron, and identify the general function of each: initial segment

-Voltage gated Na+ channels -- Na moving in -Voltage gated K+ channels -- K moving out -Na+/K+ exchange pump -Na+ leak channels -K+ leak channels

Describe seven functions of the hypothalamus

-master control of the autonomic nervous system (heart rate, blood pressure, digestion, respiration) -master control of the endocrine system -regulation of body temperature (thermostat that measures blood temperatures) -control of emotional behavior (pleasure, aggression, fear, contentment) -control of food intake (hunger) -control of water intake (thirst) -regulation of sleep-wake (circadian) rhythms

describe how acetylcholine functions as a neurotransmitter

-is synthesized from acetate and choline in the knobs -released by exocytosis into the synaptic cleft -some ACh is broken down then reused again, other ACh binds to receptors on the target cell and then dissociates, that is when the AChE breaks down the ACh

describe the pia mater

-is the innermost (deepest) of cranial meninges, and is a thin layer of delicate connective tissue that tightly adheres to the brain and follows every contour of the brain surface

describe the composition and function of the myelin sheath

-is the insulating covering around an axon that consists of repeating concentric layers of the plasma membrane of glial cells -contains lipids, and gives the axon a distinct glossy, white appearance -completed by neurolemmocytes in the PNS

How do Na/K pumps play a role in establishing the RMP?

-they do not really help in establishing the RMP -instead they play a more significant role in maintaining gradients of K and Na following the diffusion of these ions as part of the neurons electrical current -these pumps use ATP and are active -if no concentration gradient nothing moves -3 Na out, 2 K in

explain how the resting membrane potential (RMP) is established and maintained in neurons

-it is dependent on the distribution of the ions and other substances such as negatively charged phosphates and negatively charged proteins, these have a higher concentration in the ICF -the RMP is cheifly a consequence of the movement of ions across the plasma membrane through K and Na leak channels

what is the structure and function of the glial cell called ependymal cells?

-line the internal cavities of the brain and spinal cord -these along with capillaries form the choroid plexus

what is the difference between unmyelinated axons in the PNS and CNS?

-unmyelinated axons in the PNS are associated with neurolemmocytes but no myelin sheath covers them. -unmyelinated axons in the CNS are NOT associated with oligodendrocytes

describe the arachnoid mater and the spaces found around it

partially composed of a delicate web of collagen and elastic fibers called arachnoid trabeculae -immediately deep to the arachnoid mater is the subarachnoid space which contains cerebrospinal fluid -superficial to the arachnoid mater but deep to the dura mater is a space called the subdural space

What features does a neurons cell body contain?

perikaryon (cytoplasm), free and bound ribosomes (chromatophilic substance or nissl bodies), is the cells control center, and conducts electrical signals to the axon

a layer in the neuron that wraps fascicles

perineurium

the part of astrocytes that cover and wrap around capillaries in the brain

perivascular feet

Graded potentials that occur in postsynaptic neurons are specifically called... and can either be excitatory or inhibitory

postsynaptic potentials

when the neuron is at resting, its membrane potential is -70 mV and is more specifically called

resting membrane potential

anterior or toward the nose (front) - directional term when referring to the brain

rostral

type of propagation that occurs in myelinated axons, where action potentials occur only in the neurofibril nodes in between the myelinated regions of the axon, have a limited number of voltage gated Na and K channels. limiting the movement of ions

saltatory conduction

describe the two primary factors that influence the velocity of action potential propagation

1. diameter of the axon- large diameter=less resistance=quick threshold value= faster propagation of action potential small diameter= more resistance 2. myelination of the axon- saltatory (skipping) conduction= faster propagation of action potential

compare and contrast the structure and locations of the three meninges, and list the spaces found between the meninges

1. dura mater- most superficial 2. arachnoid mater- intermediate 3. pia mater- deepest

Describe the 5 distinguishing features common to all neurons

1. excitability- responsiveness to stimuli 2. conductivity- conduct an electrical signal, can be graded or an action potential 3. secretion- releases neurotransmitters that can be excitatory or inhibitory 4. extreme longevity- lives a long time 5. amitotic- not capable of mitosis

describe the 4 cranial dural septa, and give their locations

1. falx cerebri- in the cerebrum 2. tentorium cerebelli- in the cerebellum 3. falx cerebelli- in the cerebellum 4. diaphragma sellae- has to do with the sella turcica on the sphenoid bone and covers the pituitary gland

identify the four classes of neurotransmitters based upon chemical structure

Acetylcholine (Ach): -can be excitatory or inhibitory -found in both the PNS and CNS -found at a neuromuscular junction Biogenic amines: -involve a removal of a carbonyl group (COOH) and the addition of another functional group -contain a subgroup called catecholamines (norepinephrine, epinephrine, and dopamine) Amino Acids Neuropeptides

describe a unipolar neuron

second most common neuron, branches like a T. has peripheral process ( from dendrites to cell body) and central process (from cell body to CNS)

explain what an action potential is

self-propagating

are paired, irregular masses of gray matter buried deep within the central white matter in the basal region of the cerebral hemispheres inferior to the floor of the lateral ventricle. In general, they help regulate motor output initiated by the cerebral cortex, and seem to help inhibit unwanted movements.

Cerebral nuclei

the lateral ventricles are separated by a thin membrane called the...

septum pellucidum

what features does a neurons dendrites contain?

short branches off the cell body, receive input and transfer it to the cell body for processing

identified as the paired oval masses of gray matter that lie on either side of the third ventricle where they form the superolateral walls of the third ventricle.

thalamus

identify the brain areas in which cognition occurs

the association areas of the cerebrum

compare graded potentials and action potentials

Graded potentials: -generated at receptive segment -need a neurotransmitter to open chemically gated Na, K, and Cl channels -depolarization or hyperpolarization -Another name for IPSP or EPSP Action Potential: -Generated at initial segment and propagated down conductive segment -voltage gated Na and K channels -depolarization followed by repolarization

compare and contrast the distribution of gray and white matter throughout the brain divisions

Gray Matter: primarily derives its color from the motor neuron and interneuron cell bodies and their associated capillary beds, as well as the neuronal dendrites and some unmyelinated axons White Matter: derives its color from the myelin on the abundant myelinated axons

identify the criteria used to distinguish the groups of nerve fibers: Group A, B, and C

Group A: -as fast as 150 meters per second -large diameter -myelinated -most somatic sensory neurons from receptors to CNS -all somatic motor that extend from CNS to skeletal muscle Group B: -as fast as 15 meters per second -small in diameter -unmyelinated -sensory visceral and motor autonomic neurons -somatic sensory neurons from receptors of skin to CNS Group C: -as fast as 1 meter per second -small in diameter -unmyelinated -sensory visceral and motor autonomic neurons -somatic sensory neurons from receptors of skin to CNS

controls the movement of substances from exiting the blood and entering the nervous tissue in the brain while allowing nutrients to pass through

blood brain barrier

what are nerves made of?

bundles of axons

discuss the different mechanisms for removing neurotransmitter from the synaptic cleft

by degradation- when it is chemically broken apart and inactivated in the synaptic cleft or by reuptake- when it is pushed back into the synaptic knob repackaged and reused

composed of a presynaptic neuron, which is a signal producer, and a postsynaptic neuron, which is the signal receiver. a neurotransmitter is released from presynaptic neuron into the synaptic cleft

chemical synapse

what specific place is the cerebrospinal fluid formed?

choroid plexus, a region in each ventricle

What are ganglia made of?

clusters of neuron cell bodies

mental processes such as awareness, knowledge, memory, perception, and thinking are collectively called...

cognition

describe the structure of a nerve, include the three layers of connective tissue wrappings

collection of axons in the peripheral nervous system. wrappings include the epineurium, perineurium, and endoneurium.

a thick layer of connective tissue that encloses the entire nerve and provides both support and protection (surrounds the nerve)

epineurium

this type of graded potential results in depolarization when the (excitatory/inhibitory) neurotransmitter is released

excitatory postsynaptic potential (EPSP)

what do ependymal cells do?

help with the production of cerebrospinal fluid

this type of graded potential results in hyperpolarization when the (excitatory/inhibitory) neurotransmitter is released

inhibitory postsynaptic potential (IPSP)

the overlapping inner layers of plasma membrane form the...

myelin sheath

the process by which a part of an axon is wrapped with myelin

myelination

a cablelike bundle of parallel axons that are components of the PNS

nerve

bundle of axons in the PNS

nerve

as the neurolemmocyte wraps around the axon, the periphery (outside edge) of the neurolemmocyte contains cytoplasm and nucleus, and this is called the...

neurilemma

what are the gaps that are formed between the sections of myelinated neurons called?

neurofibril nodes or nodes of Ranvier

the release of chemicals from cells that locally regulate or alter the response of neurons to neurotransmitters.

neuromodulation

various small, organic compounds that are released at the synaptic cleft and then are quickly removed from the synaptic cleft

neurotransmitter

what is a voltage gated channel?

normally closed but open in response to changes in the electrical charge (potential) across the membrane and allow a specific ion to move down its concentration gradient. Ex: voltage gated Na+, K+, and Ca+ channels

trace the circulation of cerebrospinal fluid, beginning with its origin and ending with its removal

lateral ventricles -> interventricular foramen -> third ventricle -> cerebral aquaduct -> fourth ventricle -> lateral apertures and medial apertures -> subarachnoid space OR fourth ventricle -> central canal of the spinal cord

Explain what a graded potential is

local and short lived

explain temporal summation

occurs when a single presynaptic neuron releases excitatory neurotransmitter to stimulate the postsynaptic neuron at the same location repeatedly in a very short period of time

explain spacial summation

occurs when multiple presynaptic neurons release neurotransmitter at various locations onto the receptive segment of the postsynaptic neuron, thus generating EPSPs, IPSPs, or both

describe an anaxonic neuron

only have dendrites and do not have axons, produce graded potentials but not action potentials. looks like a star

deep to the cerebral cortex is the...

white matter

what is anterograde transport?

the movement of materials from the cell body to synaptic knobs

there are 6 major modified veins called dural venous sinuses, what is it that they do? (1. superior sagittal sinus, 2. inferior sagittal sinus, 3. transverse sinus, 4. sigmoid sinus, 5. straight sinus, 6. occipital sinus)

they are veins that carry and drain blood from the brain

the amount of difference in electrical charge between two areas. the larger the difference in charge, the greater the difference. represents potential energy

voltage

Name the parts and landmarks of the cerebellum

**The cerebellum is the second largest part of the brain. **The cerebellum has a complex, highly convoluted surface covered by a layer of cerebellar cortex. **The folds of the cerebellar cortex are called folia. **The cerebellum is composed of left and right cerebellar hemispheres and anterior and posterior lobes. **The lobes are separated by the primary fissure. **A narrow band of cortex known as the vermis lies along the midline between the left and right cerebellar lobes.

identify the 4 cerebral nuclei and explain their functions

**caudate nucleus When a person begins to walk, the neurons in this nucleus stimulate the appropriate muscles to produce the pattern and rhythm of arm and leg movements associated with walking. **lentiform nucleus It is a compact, rounded mass, made up of both the putamen and globus pallidus. The putamen functions in controlling muscular movement at the subconscious level. The globus pallidus both excites and inhibits the activities of the thalamus to control and adjust muscle tone. **amygdaloid body It participates in the expression of emotions, control of behavioral activities, and development of moods. **claustrum It processes visual information at a subconscious level.

identify the specific functions of left and right hemispheres in most individuals

**left hemisphere: motor speech, language comprehension, mathematical comprehension, and right visual field in each eye **right hemisphere: musical ability, recognition of faces and spatial relationships, and left visual field in each eye

describe the conditions of a neuron at rest

- K in ICF > ECF - Na in ECF > ICF - Cl in ECF > ICF - Na/K exchange pumps are responsible for the concentration gradient for Na and K - Ca concentration gradient exsists in the knob because of the Ca pumps (Ca in ECF > ICF) - chemically gated and voltage gated channels are normally closed in their locations - there is an electrical charge difference (an electrical chemical gradient) across the plasma membrane and is called a membrane potential - resting membrane potential is typically -70 mV

describe the dura mater and the spaces found between it

--is composed of 2 layers -periosteal layer (most superficial layer) and the meningeal layer (immediately superficial to the arachnoid) --the dura mater and the bones of the skull might be seperated by a potential epidural space which contains the arteries and veins that nourish the meninges and bones of the cranium

what is the threshold membrane potential? and what happens when the threshold is reached?

-55 mV, when it is reached, it initiates the opening of voltage gated channels and the generation of an action potential beginning in the initial segment and then traveling along the axon

explain the CSF production and removal process

-CSF circulates through the ventricles and then enters the subarachnoid space. -excess CSF is continuously removed from the subarachnoid space so the fluid doesn't accumulate and compress or damage the nervous tissue -fingerlike extensions of the arachnoid mater project through the dura mater into the dural venous sinuses to form arachnoid villi (a collection of these make arachnoid granulation) -this allows the CSF to be released into the blood within the dural venous sinuses

explain the physical boundaries, important features, and functions of each cerebral lobe: FRONTAL LOBE

-Frontal lobe is primarily concerned with voluntary motor (i.e. skeletal muscle) functions, concentration, verbal communication, decision making, planning, and personality -The frontal lobe lies deep to the frontal bone and forms the anterior part of the cerebral hemisphere. The frontal lobe ends posteriorly at a deep groove called the central sulcus that marks the boundary with the parietal lobe. The inferior border of the frontal lobe is marked by the lateral sulcus. An important anatomic feature of the frontal lobe is the precentral gyrus, which is the mass of nervous tissue immediately anterior to the central sulcus.

How does K play a role in establishing the RMP?

-K diffusion is the most important factor in establishing a specific value for the RMP -K movement is dependent on the electrochemical gradient -K will move outward, down its concentration gradient making the inside of the cell more negative -the outward movement of K is opposed by the electrical gradient (because the outside of the neuron is already positive so it doesn't want more positive to come out) -K reaches equilibrium eventually because the electrical gradient becomes equal to the chemical gradient. -if only K leak channels were present in neurons, the RMP would be -90 mV

How does Na play a role in establishing the RMP?

-Na moves into the neuron and adds a positive charge to the inside of the cell, which contributes to the -70 mV rather than the -90mV it would have with just K -Na enters the neuron through Na leak channels and moves down its concentration gradient -Na is pulled inward by its electrical gradient -because the number of Na leak channels are limited in comparison to the number of K leak channels, less Na moves into the neuron as compared to K moving out of the neuron

what is the structure and function of the glial cell called oligodendrocytes?

-have extensions that ensheath portions of the axons of many neurons -are responsible for the myelin sheath on the CNS neurons -when wrapped around the axons of multiple neurons, the fluid gets pushed to the middle

explain how nerves are classified structurally

1. cranial nerves- extend from the brain 2. spinal nerves- extend from the spinal cord

list the autonomic centers of the medulla oblongata and the actions they control

-The cardiac center regulates both the heart's rate and its strength of contraction. -The vasomotor center controls blood pressure by regulating the contraction and relaxation of smooth muscle in the walls of the smallest arteries (the arterioles) to alter these vessels' diameter. Blood pressure increases when vessel walls constrict and decreases when vessel walls dilate. -The medullary respiratory center regulates the respiratory rate. This center is influenced by the pontine respiratory center in the pons.

Three Functions of the Sensory Component of the Reticular Formation (also known as the reticular activating system RAS)

-This sensory component of the reticular formation is called the reticular activating system (RAS), and it contains sensory axons that project to the cerebral cortex. -The RAS alerts the cerebrum to incoming sensory information. -The RAS processes visual, auditory, and touch stimuli and uses this information to keep us in a state of mental alertness (blue arrows in previous illustration). -The RAS arouses us from sleep. e.g. The sound of an alarm clock can awaken us because the RAS receives this sensory stimulus and sends it to the cerebrum.

describe the anatomy and location of the ventricles

-all are lined with ependymal cells -contain cerebrospinal fluid -all of them communicate with eachother along with the central canal of the spinal cord -there are 4 of them in the brain: *right lateral ventricle *left lateral ventricle *third ventricle *fourth ventricle

what are the structure and function of neurolemmocytes (glial cells) found in the PNS?

-also called Schwann cells and ensheath PNS axons to form the myelin sheath -very much the same as oligodendrocytes, do the same thing except in different places

list the distinguishing features of glial cells

-are found in the CNS and PNS and are capable of mitosis -do not transmit nerve signals, but do assist neurons with their functions -physically protect, nourish, and guide migrating neurons during human development -far outnumber neurons

identify the actions of superior olivary complex

-are located in the inferior pons. -This complex receives auditory input and is involved in the pathway for sound localization.

what is the structure and function of the glial cell called microglia?

-are the smallest in number -are phagocytic immune cells and engulf infectious agents and remove debris from dead or damaged cells

describe how neurotransmitters are classifed based upon function

-based on whether or not it is excitatory (induce an EPSP, turn on) or inhibitory (induce an IPSP, turn off) neurotransmitters -also based on whether the target response is direct or indirect. direct would mean that the neurotransmitter directly binds to the receptor causing an opening of the ion channel and indirect would be after it binds to a receptor it has a bunch of reactions to turn on or off

list the major features of the midbrain

-cerebral peduncles -substantia nigra -tegmentum -tectum with superior and inferior colliculi -nuclei of cranial nerves (III and IV)

list the channels and pumps that are located along the entire neuron, and identify the general function of each: receptive segment

-chemically gated Na+ -- moves Na+ in -chemically gated K+ -- moves K+ out -Chemically gated Cl- -- moves Cl- in -Na+/K+ exchange pump -Na+ leak channels -K+ leak channels

list the seven structures that compose the limbic system and summarize some of the components actions

-cingulate gyrus **parahippocampal gyrus in the temporal lobe **hippocampus in the temporal lobe Both the hippocampus and the parahippocampal gyrus are essential in forming and storing short-term memories and forming long-term memory. **amygdaloid body in the temporal lobe The amygdaloid body is involved in several aspects of emotion, especially fear. It can also help store and code memories based on how a person emotionally perceives them—for example, as related to fear, extreme happiness, or sadness. **olfactory bulbs, olfactory tracts, and olfactory cortex (i.e. smell) -fornix (superior to thalamus) -various nuclei in the diencephalon (anterior thalamic nuclei, the habenular nuclei, the septal nuclei, and the mammillary bodies)

explain the functions of the cerebellum

-coordinates and "fine tunes" skeletal muscle movements -stores memories of previously learned movement patterns (for how you do something... walking patterns) -receives information coming from the senses (proprioceptors-where my body is in space, body position, balance) to regulate body's position in space

List the components located in the epithalamus and describe their functions

-pineal gland, or pineal body, is an endocrine gland. It secretes the hormone melatonin, which appears to help regulate day-night cycles known as the body's circadian rhythm -habenular nuclei help relay signals from the limbic system to the midbrain and are involved in visceral and emotional responses to odors.

compare and contrast the action of excitatory and inhibitory neurotransmitters in developing both excitatory and inhibitory postsynaptic potentials (i.e. graded potentials) in the receptive segment

-presynaptic neuron releases neurotransmitter that binds with receptors (chemically gated channels) in the receptive segment of the postsynaptic neuron -the chemically gated channels of the receptive segment of the postsynaptic neuron open when a neurotransmitter binds -specific ions (Na, K, Cl) cross the membrane, initiating a graded potential in the postsynaptic neuron which is local and short lived and involves a small voltage change in the RMP

describe the events that occur when the propagated action potential reaches the transmissive segment

-prior to the action potential arriving there, Ca pumps will set up a concentration gradient by pumping Ca out of the neuron and into the interstitial fluid -the action potential reaches the knobs -voltage gated Ca channels open and Ca moves into the knobs, down their concentration gradient -Ca binds to proteins of synaptic vesicles -vesicles fuse with the plasma membrane in the knob and the neurotransmitter is released by exocytosis into the synaptic cleft -neurotransmitters diffuse across the cleft and bind to protein receptors on another neuron or an effector

Describe the components and function of the reticular formation

-projects vertically through the core of the midbrain, pons, and medulla oblongata and is a loosely organized core of gray matter. -extends slightly into the diencephalon and the spinal cord as well. -has both motor and sensory components.

describe the main features of the medulla oblongata

-pyramids of the medulla oblongata - anterior, longitudinal ridges that house the motor projection tracts called the -corticospinal (pyramidal) tracts; decussation happens here. -olive with inferior olivary nuclei - relay sensory impulses to the medulla oblongata -nuclei of cranial nerves (VIII, IX, X, XI, and XII) -cardiac center -vasomotor center -medullary respiratory center

identify and describe the four functional neuron segments.

-receptive segment- includes the dendrites and the cell body, which receive stimuli. has more Na moving in than K moving out -initial segment- is composed of the axon hillock -conductive segment- consists of the length of the axon and the telodendria -transmissive segment- includes the synaptic knobs

Two Functions of the Motor Component of the Reticular Formation

-regulating muscle tone especially when the muscles are at rest -assists in autonomic motor functions, such as respiration, blood pressure, and heart rate, by working with the autonomic centers in the medulla and pons

describe and graph an action potential. use depolarization and repolarization in your explanation

-starting at the RMP at -70 mV, summation will begin (graded potentials reach the axon hillock and are all added together) -so soon as it reaches -55 mV, depolarization occurs, action potential begins. Voltage gated Na channels open and Na enters rapidly, making it more positive (from -55 to +30) -repolarization occurs due to the voltage gated Na channels closing (go from positive to more negative and back down to RMP) and opening of voltage gated K channels. K moves out of the cell into the IF and polarity goes from positive to negative -hyperpolarization occurs when voltage gated K channels stay open longer than the time needed to reach the RMP; during this time the membrane potential goes less than the RMP of -70 mV -voltage gated K channels close and the plasma membrane returns to RMP by the activity of Na/K pumps

explain how the blood brain barrier protects the brain

-strictly regulates which substances can and cannot enter the interstitial fluid of the brain -helps prevent exposure of neurons in the brain to drugs, waste products in the blood, and variations in levels of normal substances that could adversely affect brain function -however, the brain is not absolute. some things can still pass through like nicotine, alcohol, and some anesthetics. -also drugs such as cocaine and methamphetamines can damage this barrier

Explain the involuntary actions produced by the superior and inferior colliculi of the tectal plate

-superior colliculi are the superior nuclei. They are called visual reflex centers because they help visually track moving objects and control reflexes such as turning the eyes and head in response to a visual stimulus. e.g. The superior colliculi are at work when you think you see a large animal running at you and turn suddenly toward the image. -paired inferior colliculi are the auditory reflex centers, meaning that they control reflexive turning of the head and eyes in the direction of a sound, such as a sudden loud bang.

what is the structure and function of the glial cell called astrocytes?

-the most abundant glial cell -help form the blood brain barrier with their perivascular feet by covering and wrapping around capillaries in the brain

describe the general anatomic features of the brain

-there is a left and right hemisphere -there are 5 lobes: frontal, parietal, occipital, temporal, and insular lobes -the surface is composed of 3 features: gyrus, sulcus and fissures

what are the steps in the generation of EPSP's

1. Excitatory neurotransmitter crosses the synaptic cleft and binds specifically to a receptor that is a chemically gated cation channel, causing it to open 2. more Na moves down its concentration gradient into the neuron than K moves out 3. the inside of the neuron becomes slightly more positive by gaining the positively charged Na ions 4. the local current becomes weaker as it moves along the neuron plasma membrane toward the initial segment (axon hillock) and decreases in intensity with the distance traveled

Explain the functional organization of the nervous system (2 functional divisions)

1. Sensory (afferent) nervous system- receives sensory information from the receptors and transmits the information to the CNS 2. Motor (efferent) nervous system- Initiates and transmits motor output from the CNS to the effectors

What are the 2 subdivisions of the motor nervous system?

1. Somatic motor division- initiates and transmits motor output from the CNS to voluntary skeletal muscles (like throwing a ball) 2. Autonomic motor division- innervates and regulates cardiac muscle, smooth muscle, and glands without our conscious control.

What are the 2 subdivisions of the sensory nervous system?

1. Somatic sensory division- detect stimuli we consciously perceive (getting stung by a bee) 2. Visceral Sensory division- detect stimuli we do not consciously perceive

what are the four types of glial cells within the CNS?

1. astrocytes 2. ependymal cells 3. microglia 4. oligodendrocytes

explain the 3 functions of cerebrospinal fluid

1. buoyancy: CSF prevents parts of the heavy brain from sinking through the foramen magnum 2. protection: CSF is a movement buffer 3. environmental stability: transports nutrients and chemical messengers to the brain and removes waste products from the brain. also protects nervous tissue from chemical fluctuations that would disrupt neuron function

Decribe the three basic anatomic features common to most neurons.

1. cell body 2. dendrites 3. axon

Describe the three general functions of the nervous system

1. collects information- monitors changes in stimuli from external and internal environments 2. processes and evaluates information- then determines what the response will be 3. initiates a response to the information- information then sent via motor nerves to the effectors

what are the steps in the generation of IPSP's

1. inhibitory neurotransmitter crosses the synaptic cleft and binds to a chemically gated K channel or a chemically gated Cl channel on the receptive segment of a postsynaptic neuron 2. if neurotransmitter binds to chemically gated K channel, the channel will open and K moves out making the neuron more negative inside. if the neurotransmitter binds to a chemically gated Cl channel, the channel will open and the Cl moves into the neuron making it more negative inside the neuron 3. both of these situations make the inside of the slightly more negative- this more negative state is called the IPSP 4. the current of ions becomes weaker as it moves along the neuron plasma membrane toward the axon hillock and decreases in intensity with the distance traveled

Name and describe the 4 structural categories of neurons

1. multipolar 2. bipolar 3. unipolar 4. anaxonic

describe the myelination process carried out by oligodendrocytes in the CNS

1. myelination occurs via an oligodendrocyte but the axons are myelinated many at a time, rather than 1 at a time 2. no neurolemma is formed

describe the myelination process carried out by neurolemmocytes in the PNS

1. neurolemmocytes start to wrap around a portion of an axon 2. neurolemmocyte cytoplasm and plasma membrane begin to form consecutive layers around the axon as wrapping continues 3. the over lapping inner layers of the neurolemmocyte plasma membrane form the myelin sheath (pushing the nucleus and cytoplasm to the outside) 4. eventually, the neurolemmocyte cytoplasm, and nucleus are pushed to the periphery of the cell as the myelin sheath is formed

What are the 2 glial cells of the PNS?

1. satellite cells 2. neurolemmocytes

explain how nerves are classified functionally

1. sensory nerves- contain only sensory neurons 2. motor nerves- contain only motor neurons 3. mixed nerves- contain both sensory and motor neurons

What are the three functional categories of neurons and where are each of them primarily located?

1. sensory neurons (afferent neurons)- responsible for conducting sensory input from both the somatic sensory and visceral sensory receptors to the CNS, mostly unipolar, and have cell bodies located in the posterior root ganglia 2. motor neurons (efferent neurons)- responsible for conducting motor output from the CNS to both somatic effectors and visceral effectors, all are multipolar, and have cell bodies that lie in the CNS 3. Interneurons (association neurons)- lie entirely in the CNS, receive and pass information to next neuron, are multipolar, and are generally between a sensory neuron and a motor neuron

how do Na+ and K+ go in and out of the cell via the sodium/potassium exchange pump?

3 Na+ leave the cell and 2 K+ enter the cell -uses ATP

what are the 3 types of channels?

Leak channels chemically gated channels voltage gated channels

identify the three main tracts of the central white matter

Association tracts connect several cortical areas within the same hemisphere. -arcuate and longitudinal fasciculi Commissural tracts extend between the cerebral hemispheres via axonal bridges called commissures. -corpus callosum Projection tracts link the cerebral cortex to both the brainstem and the spinal cord. -corticospinal tracts in the internal capsule

discriminate between the left and right cerebral hemispheres with respect to their general functions

As a general rule, both cerebral hemispheres receive their sensory information from, and project motor commands to, the opposite side of the body. The right cerebral hemisphere controls the left side of the body, and vice versa.

Identify the structure components included in both the CNS and the PNS

CNS: made up of the brain and spinal cord PNS: made up of nerves and ganglia

explain the phenomenon of cerebral lateralization

Each hemisphere tends to be specialized for certain tasks, a phenomenon called cerebral lateralization.

explain how circadian rythym is regulated

It secretes the hormone melatonin, which appears to help regulate day-night cycles known as the body's circadian rhythm.

list and explain the three states of voltage gated Na+ channels

Resting state: closed - no Na+ into the cell -inactivation gate open -activation gate closed Activation state: open - Na+ moving through channel and into the cell -inactivation gate open -activation gate open Inactivation state: closed - no Na+ into the cell -inactivation gate closed -activation gate open

What are the two types of summation that can occur in the initial segment and explain what is happening

Spacial summation and temporal summation. both of these are occuring at the same time. when graded potentials (summation of excitatory and inhibitory postsynaptic potentials) arrive at the initial segment within a small period of time, they can either contribute to or interfere with the threshold value of -55 mV being reached. -once the graded potentials reach the -55 mV threshold, and action potential occurs -the action potentials are self sustaining, travel all the way down the axon, and follow the all or none law

the opposing force holding back the current. an example of this would be the cell membrane. the larger this is, the lower the current is

resistance

Explain the physical boundaries, important features, and functions of each cerebral lobe: INSULA

The insula is a small lobe deep to the lateral sulcus. It can be observed by laterally reflecting (pulling aside) the temporal lobe. The insula's lack of accessibility has prevented aggressive studies of its function, but it is apparently involved in memory and the interpretation of taste (i.e. gustatory perception).

Explain the physical boundaries, important features, and functions of each cerebral lobe: OCCIPITAL LOBE

The occipital lobe lies internal (i.e. deep) to the occipital bone and forms the posterior region of each hemisphere. This lobe is responsible for processing incoming visual information and storing visual memories

explain the physical boundaries, important features, and functions of each cerebral lobe: PARIETAL LOBE

The parietal lobe lies deep to the parietal bone. The parietal lobe terminates anteriorly at the central sulcus, posteriorly at a relatively indistinct parieto-occipital sulcus, and laterally at the lateral sulcus. An important anatomic feature of this lobe is the postcentral gyrus, which is the mass of nervous tissue immediately posterior to the central sulcus. The parietal lobe is involved with general sensory functions, such as evaluating the shape and texture of objects being touched.

explain the functions of the prefrontal cortex, and hypothesize why this brain region may function differently in adults and teenagers

The prefrontal cortex is located in the frontal lobe anterior to the premotor and primary motor cortices and is associated with many higher intellectual functions. Complex thought, judgment, expression of personality, planning future behaviors, and decision making

identify the three tracts through which the brainstem is linked to the cerebellum

The superior cerebellar peduncles connect the cerebellum to the midbrain. The middle cerebellar peduncles connect the pons to the cerebellum. The inferior cerebellar peduncles connect the cerebellum to the medulla oblongata.

explain the physical boundaries, important features, and functions of each cerebral lobe: TEMPORAL LOBE

The temporal lobe lies internal (i.e. deep) to the temporal bone and inferior to the lateral sulcus. This lobe is involved with hearing and smell sensations.

Discuss the action of the thalamus on sensory information

The thalamus is the principal and final relay point for incoming sensory information that is processed and then projected to the primary somatosensory cortex. The thalamus acts as an information filter. e.g. filtering out the sounds and sights in a busy dorm cafeteria when you are trying to study The thalamus also "clues in" the cerebrum about where this sensory information came from. e.g. The thalamus lets the cerebrum know that sensory information it receives came from the eye, indicating that the information is visual.

conversion from STM to LTM is called...

encoding or memory consolidation

compare and contrast the main actions of the Wernicke area and the gnostic area

Wernicke area is typically located only within the left cerebral hemisphere in the superior temporal region. The Wernicke area is involved in recognizing, understanding, and comprehending spoken or written language. As you may expect, the Wernicke area and the motor speech area (Broca area) must work together for fluent communication to occur. The gnostic area (or common integrative area) is composed of regions of the parietal, occipital, and temporal lobes. This region integrates all somatosensory, visual, and auditory information being processed by the association areas within these lobes. Thus it provides comprehensive understanding of a current activity. For example, suppose you awaken from a daytime nap, the hands on the clock indicate that it is 12:30 P.M., you smell food cooking, and you hear your friends talking about being hungry. The gnostic area then interprets this information to mean it is lunchtime.

a layer of connective tissue withing the nerve that surrounds an individual axon in a myelinated neuron

endoneurium

describe a bipolar neuron

has two things coming off the cell body- one axon, and one dendrite

what two things make up the choroid plexus?

a layer of ependymal cells and the blood capillaries

identify the four different types of neuronal pools, and explain how they function.

a. converging circuit- is many presynaptic neurons converging into one neuron. ex: producing saliva at mealtime b. diverging circuit: one presynaptic neuron spreads info to many postsynaptic neurons. ex: sending signals to many muscles at once

is the time (about 1 millisecond) after an action potential onset when no amount of stimulus, no matter how strong, can initiate a second action potential. so because of the state of the membrane potential and the voltage gated channels (inactivation state) it would be near impossible to initiate another action potential

absolute refractory period

what is a leak channel?

always open and allow a specific ion to move down its concentration gradient. specific to Na+ or K+ only

name the two regions of the limbic system involved in conversion of short-term memory to long-term memory

amygdaloid body and hippocampus

what is a chemically gated channel?

are normally closed but open in response to a neurotransmitter and allow a specific ion to move down its concentration gradient. ex: K+, Na+, Cl- channels

what features does a neurons axon contain?

axon hillock, axolemma (plasma membrane), axoplasm (cytoplasm), axon collaterals (side branches), and its collaterals have telodendria (axon terminals at their distal ends) along with synaptic knobs

describe the components that form the blood-brain barrier

capillary endothelial cells and the astrocyte perivascular feet make up the blood brain barrier

posterior or toward the tail (back) - directional term when referring to the brain

caudal

the fourth ventricle merges with the...

central canal of the spinal cord

the third ventricle communicates with the fourth ventricle via the...

cerebral aquaduct

the surface of the cerebrum is gray matter and is called the...

cerebral cortex

The two hemispheres appear as anatomic mirror images, but they display some functional differences, termed

cerebral lateralization

within the masses of white matter, the brain also contains discrete internal clusters of gray matter called... which are also made up of neuronal cell bodies

cerebral nuclei

a clear, colorless liquid that circulates in the ventricles and subarachnoid space, bathes the exposed surfaces of the central nervous system and completely surrounds it.

cerebrospinal fluid

what does the choroid plexus form?

cerebrospinal fluid

Identify the role of the corpus callosum

connects the hemispheres and provides the main method of communication between these hemispheres, also The largest of the white matter tracts

type of propagation that occurs in unmyelinated axons and involves the sequential opening of voltage gated Na channels and voltage gated K channels located within the axon plasma membrane, have a large number of voltage gated Na and K channels

continuous conduction

the three connective tissue layers that separate and support the soft tissue of the brain from the bones of the cranium, enclose and protect some of the blood vessels that supply the brain, and help contain and circulate cerebrospinal fluid

cranial meninges

the movement of charged particles across the barrier that seperates this charge difference. Na, K, Cl, and Ca are charged particles. the greater the movement of charged particles the greater -this- is

current

describe how action potentials vary in frequency

depending on the strength of the stimulus. as the strength of the stimulus increases so does the frequency of action potentials per second. it is a direct relationship

a change in the RMP in the positive direction caused by the opening of Na chemically gated channels and the movement of Na into the cell. draw the graph

depolarization

when a presynaptic neuron and a postsynaptic neuron are physically bound together by gap junctions, which allow the flow of ions through. there is no synaptic delay with these

electrical synapse

what are the two effects of neuromodulation?

facilitation- when there is a greater response from the postsynaptic neuron because of the release of the neuromodulators. this is due to either an increased amount of neurotransmitter in the synaptic cleft or an increase in the number of receptors on the postsynaptic neuron inhibition- occurs when there is less response from the postsynaptic neuron because of the release of neuromodulators. this is due to either a decreased amount of neurotransmitters or a decreased amount of receptors on the postsynaptic neuron

bundles of axons within the nerve are called

fascicles

a deep groove in the cerebrum

fissure

What are the structure and function of satellite cells (glial cells) found in the PNS?

flattened cells arranged around neuronal cell bodies in ganglion -physically separate cell bodies from the surrounding interstitial fluid (ECF) -regulate the continuous exchange of nutrients and waste

Name the general function of each lobe

frontal lobe: movement (skeletal muscle movement) -personality -decision making Parietal Lobe: general senses, touch, pain, pressure, stretching (of skin) Temporal Lobe: hearing- auditory -uncus- smell- olfaction Occipital Lobe: vision Insular Lobe: gustatory- taste

group of tracts in a specific area of the spinal cord

funiculus

cluster of neuron cell bodies in the peripheral nervous system

ganglion

a raised fold in the cerebrum

gyrus

a change in the RMP in the negative direction caused by the opening of K chemically gated channels and the movement of K out of the cell and by the opening of Cl chemically gated channels and the movement of Cl into the cell. draw the graph

hyperpolarization

a small, midline mass of gray matter that connects the right and left thalamic bodies.

interthalamic adhesi

each lateral ventricle communicates with the third ventricle via an opening called...

interventricular foramen

Describe a multipolar neuron

is the most common, and has many dendrites and a single axon

What is fast axonal transport? and give an example of this

movement along microtubules that occurs at approximately 400 mm per day. vesicles, organelles, and glycoproteins (all anterograde). potentially harmful agents (retrograde)

what is retrograde transport?

movement of materials from the synaptic knobs to the cell body

What is slow axonal transport and give an example of this

movement with the flow of axoplasm that occurs at approximately .1-3 mm per day. Enzymes, cytoskeletal components, and new axoplasm (all anterograde)

distinguish between a pump and a channel, and describe the three specific states of a voltage-gated sodium channel

pumps- move substances across the plasma membrane up (against) their concentration gradient ex: Na+/K+ exchange pumps, Ca pumps Channels- provide a means to move the substance down (with) its concentration gradient. from high solute to low solute. is not active and is a protein with a passageway

describe the main functions of the limbic system

referred to as the emotional brain, there is often interplay of emotions, memories, and smells. (spouse dying- holds onto clothes from spouse and envokes a lot of emotions)

the brief time after an action potential has been initiated during which an axon is either incapable of generating another action potential OR a greater than normal amount of stimulation is required to generate another action potential

refractory period

occurs immediately after the absolute refractory period. it is during this period that the voltage gated channels have returned to their resting state but the neuron is hyperpolarized due to the extension time of the voltage gated K channels remaining open during repolarization. we could get another action potential here but we would need a very strong stimuli at the receptive segment to move up super fast from -80 mV to -55 mV

relative refractory period

what is it called when any graded potential is less that -55 mV?

subthreshold value

a shallow depression in the cerebrum

sulcus

graded postsynaptic potentials (EPSP's and IPSP's) are added together in the initial segment, this is called....

summation

the specific location where a neuron is functionally connected to either another neuron or an effector

synapse

the presynaptic neuron and the postsynaptic neurons are seperated by a fluid-filled gap called ...

synaptic cleft

bundles of axons within the CNS in which the axons have a similar function and share a common origin and destination

tract

cavities or expansions within the brain

ventricles