Test 2- Anatomy 1 Flashcards
Nervous System function
- _________ provides for generation of nerve impulses (action potentials) that communicate with and regulate most body tissues
- Responsibility for maintaining homeostasis is shared by the _____ and _________
- Nervous system regulates body activities by responding rapidly using _________
- Endocrine system responds more slowly by use of ________
- Nervous system
- Nervous system/Endocrine System
- Nerve impulses
- Hormones
Nervous system function
- _______ is the branch of medical science that deals with the normal functioning and disorders of the nervous system
- Neurology
Nervous System structures
- Central nervous system consist of: _______, ______
- Peripheral nervous system consist of: _______, _______, _______
- The nervous system comprises of the ______, ______, _______, ______, _______, and ________
- Brain/Spinal cord
- Cranial nerves, 12 pairs/Spinal nerves, 31 pairs/Peripheral nerves
- Brain/Spinal cord/Spinal nerves/Ganglia/Enteric Plexuses/Sensory receptors
Functions of the Nervous System
- ______ detect changes in the internal or external environment
- Sensory neurons are _______ neurons
- ________ analyze and store information, make decisions
- _______ respond to decisions, carry information from brain and spinal cord to ______
- Motor neurons are _______ neurons
- Sensory receptors
- Afferent
- Integrative
- Motor neurons/Effectors
- Efferent
General organization of the Nervous System
- ______ is sensation from body wall, limbs, head, special sense. Motor control of skeletal muscle (Voluntary control)
- ______ is sensation from internal organs like heart, lungs, bladder. Motor control of smooth and cardiac muscle gland (Involuntary control)
- _______ Is sensation from gastrointestinal tract. Motor control of smooth muscle and glands of the gastrointestinal tract (Involuntary control)
- Somatic
- Autonomic
- Enteric
Organization of the nervous system
- _______ consist of all nervous tissue outside the central nervous system
- Each subdivision of the PNS has both ______ and _____ neurons.
- The motor part of the autonomic nervous system consist of two branches _______ and _______
- Peripheral nervous system
- Sensory/motor
- Sympathetic/Parasympathetic
Terms associated with assemblages of neurons
- _____ is an association (a bundle) of neuronal axons in the Peripheral Nervous system
- ______ is a group of neuronal cell bodies in the Peripheral nervous system (plus associated tissues)
- Nerve/Peripheral nervous system
2. Ganglion/Peripheral nervous system
Terms associated with assemblages of neurons
- ______ is an association (a bundle) of neuronal axons in the Central nervous system
- _______ is an association (a bundle) of (unmyelinated) nerve cell bodies in the Central nervous system
- ______ is an extensive network of nerves found within the peripheral nervous system
- Tract/Central nervous system
- Nucleus/Central nervous system
- Plexus/Peripheral nervous system
Cells of the Nervous system
- ______ are cells that have the property of electrical excitability, and are specially adapted to _____ and transmit _______
- _______ are cells of the nervous system that support, nourish and protect the _____
- Neurons/Produce/Action Potentials
2. Neuroglia/Neuons
Structure of a typical neuron
- The basic parts of a neuron are _______ and nerve fibers comprising of ______, and ______
- Name adaptations for neurons are ______ and _______
- Cell body/Axon/Dendrites
2. Axoplasm (the cytoplasm of an axon)/Axolemma (the plasmalemma of axon)
Structure of a typical neuron
- Like most cells, neurons have nucleus, cytoplasm, and typical organelles…… Also they have specialized forms of typical organelles, primarily the ________, which are prominent ______ of the __________
- Nissl bodies/Clusters/Rough ER
Structure of a typical neuron
- ________: Receiving portion of a neuron. Typically short, tapering, highly branched
- _______: Propagates impulses to another neuron, muscle, or nerve. Can approximate three feet long in humans
- Dendrite
2. Axon
Structure of a Typical neuron
Axon is
- Virtually always only a ______ axon per neuron
- Typically arises from an elevation in the cell body called the ______
- First part is called the ______
- Impulses (action potentials) generally arise in the ______, ______, and _______
- Single
- Axon Hillock
- Initial Segment
- Trigger zone/Junction of hillock/initial segment
Structure of a typical neuron
- Axon contains: _______, ________, ________
- Axon does not contain: _______
- Mitochondria/Microtubules/Neurofibrils
2. Rough endoplasmic reticulum
Structure of a typical neuron
- Axon and collaterals end by dividing into _______, which end in either ______ or _______
- Axon terminals (telodendria)/Synaptic end bulbs/Varicosities
Structure of a typical neuron
- What are the 2 substructures of cytoskeleton and their function?
- -Neurofibrils:intermediate filaments, provide cell shape and support
- Microtubles: tublin, participate in moving material between the cell body and axon
Axonal Transport
- _______: 1-5mm per day, Transports axoplasm to growing or generating axons. One way only form ______ to ______
- _______: 200-400mm per day. Two way transport both 3._____ and 4._____ from 5._____. Uses 6.______ as tracks and motors. Transports organelles and materials that are used to form 7._____, ______, and _______
- Slow axonal transport/Cell body/Axon terminals
- Fast axonal transport
- Toward
- Away
- Cell body
- Microtubules
- Axolemma membranes/Synaptic end bulbs/ Synaptic vesicles
Classifying Neurons
- ______ is based on the number of processes (axons or dendrites) extending from the cell body
- ______ have several dendrites and only one axon and are located throughout the brain and spinal cord
- Structural classification
2. Multipolar neurons
Classifying Neurons
- ______ have one main dendrite and one axon. They are used to convey the special senses of sight, smell, hearing and balance
- _______ Contain one process which extends from the body and divides into a central branch that functions as an axon and as a dendritic root. This structure is often employed for sensory neurons that convey touch and stretching information from the extremities
- Bipolar neurons
2. Unipolar (pseudounipolar) neurons
- ________ not excitable cells. Smaller, more numerous than neurons, play a supporting role, and make up about half the volume of the CNS.
- In cases of injury or disease, ______ multiply to fill in the spaces formerly occupied by _______
- Neuroglia
2. Neuroglia/Neurons
Neuroglia cells and locations
- Neuroglia of the CNS: _________, ________, ________, ________
- Neuroglia of the PNS: _______, _________
- Astrocytes/oligodendrocytes/Microglia/Ependymal Cells
2. Schwann cells (neurolemmocytes)/Satellite cells
Neuroglia
- __________: Regulate the composition of the extracellular fluid in the CNS; help form the blood brain barrier, take up excess neurotransmitters, may influence formation of neural synapses
- _______: myelinate axons in the CNS
- ________: Phagocytes of the CNS
- Astrocytes
- Oligodendrocytes
- Microglia
- _________: Line the ventricles of the brain; produce, monitor, and aid in circulation of CSF; help form the blood CSF barrier
- ________: Myelinate axons in the PNS
- _________: second type of PNS neuroglia. They provide structural support and regulate exchange of materials between neuronal cell bodies and interstitial fluid
- Ependymal cells
- PNS Schwann cells
- Satellite cells
Mitosis of nervous system cells
- ________ do not typically undergo Mitosis, meaning if a neuron dies there is no reservoir of cells to replace it
- _________ do undergo mitosis
- Neurons
3. Neuroglial Cells
Myelination
- Myelination is produced by ________ and _________
- Myelin is a _______ complex of _____ and ______
- _______: myelin prevents loss of electrical signal; speeds up conduction of nerve impulses
- Myelination requires the _______ cell to have wrapped its ______ around the axon many times
- Schwann (PNS)/Oligodendrocytes (CNS)
- Multi-layered/lipids/proteins
- Insulate axons
- Glial cell/plasma membrane
Myelination in the PNS
1._______: the outer nucleated cytoplasmic layer of the Schwann cell, which encloses the myelin sheath.
- Neurolemma
Myelination Process
- ________ inner portion successively encircles the axon, formation many layers that comprise the _________
- The nucleus of the neurolemmocyte come to reside in the ______, which is the outer nucleated _________ of the Schwann cell
- Schwann Cell/Myelin Sheath
2. Neurolemma/Cytoplasmic layer
- __________:outer layer of a myelination Schwann cell, contains the nucleus and virtually all the cytoplasm, not to be confused with the Axolemma, found only around the axons in the PNS
- ________: only on nerve fibers supplied by potentially myelin producing cells. Found in PNS and CNS
- Neurolemma
2. Nodes of Ranvier
Nerve Fiber Relationships
- Nerve fiber consists of _____ plus _____ when present
- The ________ surrounds the nerve fibers. Therefore the _______ overlies the _________
- Axon/myelin sheath
2. Endoneurium/Endoneurium/Schwann Cells
Myelination in the CNS
- ________ have multiple processes, each process can form a myelinated segment.
- ________ can myelinate several segments of _____ axon or can participate in myelination of ________ axons
- A neurolemma is not present in the _____ because the Oligodendrocytes cell body and nucleus do not _________
- Oligodendrocytes
- Oligodendrocytes/1/several
- Envelop the axon
Myelination in the CNS
- One Oligodendrocyte can myelinate _______ times
- There is no _________
- There are ________
- Multiple
- neurolemma
- Nodes of Ranvier
Gray and White Matter in the central nervous system
- _________: a region predominantly filled with myelinated tract fibers. The appearance is due to the Whitt’s color of myelin
- _________: a region predominantly filled with neuronal cell bodies. There is little or no myelin in these areas, and the Nissi bodies Impact a _________
- White Matter
2. Gray Matter/Gray color
Membrane Potential
- Virtually all cells in the body exhibit a membrane. Potential, which is an _________ across the membrane
- Nerve cells are highly adapted for using membrane potentials, and changes in membrane potentials to _______ and ________ nerve impulses
- Electrical Voltage difference
2. Initiate/Transmit
Neuronal signals
Neurons communicate with one another by using two types of electrical signals:
- ___________ for both short and long distance communication within the body. This __________
- ____________ for short distance communication only. The physiological role of the ________ is to _______ and _______ the generation of action potentials.
- Both types of signal depend on two features of the plasma membrane of excitable cells: __________ and __________
- Action Potentials/All or none
- Graded Potentials/Graded potentials/affect/effect
- Existence of a resting membrane potential/presence of specific ion channels
Membrane Potential
- ________ is measured across the ________ and is relative to the _________
- Voltage/Plasma Membrane/Outside of the cell
Membrane Potential
- _________ means potential energy that can cause a flow of electrical current
- If opposite charges are separated in space, their _______ is the ______ measured in _______
- Potential
2. Attractive force/Potential/Volts
Membrane Current
- _______ is a flow of charged atoms or molecules
- ________ is the flow of electrons
- _________ means flow of ions: _______, _______, _________
- Current
- Electrical Current
- Body Current/Na+/K+/Ca2+
Ion Channels
- When ________ are open, specific ions are allowed to move across the __________ down their electrochemical gradient
- Ion Channels/Plasmalemma
- _______ is part of a channel protein that opens or closes to allow or prevent the passage of ions
- Not all ________ have gates
- Gate
2. Membrane Channels
Types of Ion Channels
- ________: not gated, randomly open and closes. The resting membrane is more permeable to K+ than to Na+
- ________: A chemical that binds to a receptor molecule. Channels open or close in response to chemical binding
- ________: Open in response to mechanical stimuli
- ________: Open and close in response to changes in the membrane potential
- Leakage channels
- Ligand gated channels
- Mechanically gated channels
- Voltage-gated channels
- ___________: is the voltage difference measured across the plasma membrane when the neuron isn’t signaling
- Membrane is _________
- All membrane potentials are reported as the _______ of the inside of the membrane ______ to the outside of the membrane.
- Varies from cell to cell averaging to _____ mV
- Resting membrane potential
- Polarized
- Potential/relative
- -70mV
Resting membrane charge distribution
- The resting membrane potential Is due to a small buildup of _______ in the cytosol just inside the ________, and an equal buildup of _______ in the _________ just outside the membrane
- Anions/Membrane/Cations/Extracellular fluid
Basis of the Resting Membrane Potential
- ____ and ____ are in higher concentration in the extracellular fluid
- ____, ______, _______, and ________ are in higher concentration in the intracellular fluid
- The resting membrane is 50 to 100 times more permeable to ____ than to _____
- _____ permeability is in between that of Na+ and K+
- The membrane is _______ to nearly all of the ______ charged intracellular molecules
- Na+/Cl-
- K+/Organic phosphates (-)/Amino acids (-)/ Proteins (-)
- K+/Na+
- Cl-
- Impermeable/negatively
Establishing the resting membrane potential
- _____ diffuses down its concentration gradient out of the cell
- The _______ charged ions are left behind because they cant get through the membrane
- The interior of the membrane becomes _______ charged; the exterior becomes _______ charged; net diffusion of ____ stops
- _______ diffuses into the cell but at a much lower rate than ____ diffuses out because the membrane is _____ permeable to _____
- A little _____ diffuses into the cell, also making the interior more ______
- Net result: _____________
- K+
- Intracellular negatively
- Negatively/Positively/K+
- Na+/K+/less/Na+
- Cl-/negative
- The resting membrane potential
Graded potentials
- _____ or ______ ion channels produce graded potentials in response to stimuli
- _______ means the size of the change in the membrane potential varies in portion to strength of the stimulus
- Local effect only: ______ open, _______ flows through the membrane and along the ________ and travels only a _______ distance before diminishing to zero
- Ligand gated/Mechanically gated
- Graded
- Channels/Current/Membrane/short
Graded potentials
- A graded potential can either ______ the membrane or ________ the membrane
- _________: Membrane becomes more polarized (more negative)
- _________: Membrane becomes less polarized (less negative or more positive)
- Depolarize/Hyperpolarize
- Hyperpolarization
- Depolarization
Action Potentials
- Once an action potential is generated it travels the _____ of the ______ and can initiate an action potential in subsequent ________, ________, or ________
- Action potentials are _________
- Length/neuron/Neurons/Muscles/Glands
2. All or None
Ion Flow during action potentials
- Resting state has both _____ and _____ voltage gated channels closed
- Depolarization has _____ gates open
- Repolarization accompanied by ____ gates open and _______ gates closed or closing
- Resting state restored finds _____ gats closed
- Na+/K+
- Na+
- K+/Na+
- K+
Action Potential
- Action potential progresses sequentially down the ____ of the _____
- Length/axon
Calcium Ion deficit
- Calcium ions appear to bind to the exterior surfaces of the ______ protein molecule
- The positive charges of the calcium ion alter the ________ of the channel protein, ________ the voltage level required to open the gate
- Absent the bound calcium ions, smaller than normal voltages are required for _________
- Sodium Channel
- Electrical state/Increasing
- Gate activation
Calcium Ion deficit
- When there is a deficit of calcium ions, the _______ channels become activated by very little change of the membrane potential from its normal resting level
- This is why low blood calcium is associated with _______, ______, and _________, which can be lethal because of titanic contraction of the __________
- Sodium Channels
2. Muscle Contraction/Cramps/Tetany/Respiratory muscles
Propagation of Nerve impulses
- Nerve impulses must travel from where they arise at a _______ typically the ________ down the neuron to the axon terminals
- That movement is called ________ or _______
- Propagation depends on _________
- Trigger zone/Axon Hillock
- Propagation/Conduction
- Positive Feedback
Positive feedback of propagation
- The inflow of sodium ions causes _________ that opens _________ Na+ channels in adjacent segments of the membrane
- Depolarization/voltage gated
Summary of neuronal structure
- ________: receive stimuli through activation of ligand-gated or mechanically gated ion channels. In sensory neurons produces generator or receptor potential. In motor neurons and interneurons produces excitatory and inhibitory postsynaptic potentials
- Dendrites
Summary of neuronal structure
- _________: Receives stimuli and produces EPSPs and IPSPs through activation of ligand gated or mechanically gated ion channels
- Cell body
Summary of neuronal structure
- __________: Trigger zone in many neurons. Integrates EPSPs and IPSPs if sum is depolarization that reaches threshold, initiatives action potential (nerve impulse)
- Junction of axon hillock and initial segment of axon
Summary of neuronal structure
- _________: Propagates (conducts) nerve impulses to axon terminals in a self reinforcing manner. Impulse amplitude does not change as it propagates along the axon
- Axon
Summary of neuronal Structure
- ________: Inflow of Ca2+ caused by depolarization phase of nerve impulse triggers exocytosis of neurotransmitter form synaptic vesicles
- Axon terminals and synaptic end bulbs (or varicosities)
Types of Conduction
- Step by step depolarization and repolarization of adjacent segments is termed ____________
- __________ is a special mode of impulse propagation that occurs along myelinated axons
- Continuous Conduction
2. Saltatory Conduction
Saltatory Conduction
- Only in ________ axons
- Voltage gated channels are concentrated at ________, with few in regions where the myelin sheath covers the Axolemma
- Electric current is carried by ______ and ________ ions from one node to the next, and the nodes _____ and _____ as previously discussed
- Myelinated
- Nodes of Ranvier
- Extracellular/Intracellular/Depolarize/Repolarize
Metabolism
- Neurons produce virtually all their ATP via ________
- This process requires large amounts of _____ so the nervous system requires a high _________and is consequently highly vascularized
- Aerobic metabolism of glucose
2. Oxygen/Blood Flow
Metabolism
- Most the brains energy consumption goes into sustaining the ______ of neurons
- Electrical charge
Effect of Axon Diameter
- The greater the _______ of the axon, the _______ the conduction will be (less resistance to the flow of ions through the axoplasm)
- _______: Large diameter, myelinated, FAST
- _______: Medium diameter, Myelinated, FAST
- _______: Small diameter, Unmyelinated, SLOW
- Diameter/faster
- A fibers
- B fibers
- C fibers
Perceiving Stimulus intensity
- Two mechanisms enable stimuli of differing intensities to be registers as such: _____________ and __________
- Frequency of impulses/Number of sensory neurons activated
Example of Intensity perception (Using Touch)
- __________: light touch generates a low frequency of widely spaced nerve impulses
- A firm pressure causes nerve impulses to go down the axon closer together
- __________: A light touch stimulates only a few pressure sensitive neurons
- A firm pressure stimulates more pressure sensitive neurons
- Frequency of impulses
2. Number of sensory neurons recruited
Stimulus strength and generation of action potential
- No action potential is generated by a _________ stimulus.
- Several action potentials result from a _______ stimulus, yet each has the same amplitude. This is perceived as a stronger stimulus
- Subthreshold stimulus
2. Suprathreshold stimulus