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21 Cards in this Set
- Front
- Back
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Central nervous system |
Contains the brain and spinal cord Integrates and processes information |
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Peripheral nervous system |
Contains everything outside the brain and spinal cord Composed of the nerves |
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Input |
The input side of the nervous system is the sensory system are sensory neurons Carrie's information about the environment up to the brain |
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Output |
The output side of the nervous system is the motor system or motor neurons Carrie's instructions from the brain down to the body tissues |
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Somatic nervous system |
Controls skeletal muscles and mostly voluntary movements |
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Automatic nervous system |
Controls smooth muscle and cardiac muscle and several glands Parasympathetic is normal body functions Sympathetic system is the fight or flight response |
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Neuroglia aka glial cells |
Do all the support activities for the nervous system such as lining and covering cavities and supporting and protecting structures
Cannot measure the environment make decisions or send orders
Specialized cells that perform special functions there are four types
Cns Astrocytes metabolic and structural support cells Microglia removed debris Ependymal cells cover and line cavities of the nervous system Oligodendrocytes makes a lipid insulation call myelin
Pns Schwann cells make myelin for Pns Satellite cells support cells
Support cells in the nervous system Myelin is a lipid sheath that surrounds and insulates the axon |
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Neurons |
Carry out all functions of the nervous system Have many branches in what appears to be a tail Body- cell metabolism Dendrites - received information from the environment or from other cells
Axon- generates and sends signals to other, portion of neuron that conducts action potential
Axon terminal is a place where the signals from the axon travel down until it reaches it which then connect to a receiving cell
Synapse- where the axon terminal and receiving cell meet If receiving cell is a skeletal muscle it is called a neuromuscular synapse or Junction, The tiny space between the neuron sending the signal and the cell receiving the signal |
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Neuron classification |
Neurons can be classified by how they look Unipolar one process with a peripheral and Central projection Bipolar two processes one axon and one dendrite Multipolar many processes Can be classified by what they do Input neurons are known as Sensory neurons output neurons are known as motor neurons Interneurons carry information between neurons |
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How neurons work |
Are excitable cells Neurons send and receive signals by tiny electrical currents When a neuron is stimulated it carries a small electrical charge when charged particles flow across the cell membrane there is a tiny charge generated
Cells are able to generate tiny current simply by changing the permeable of their membranes |
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Action potential |
Action potential is the cell moving through depolarization repolarization and hyperpolarization or a wave of depolarization and repolarization that travels down an axon
A cell that is not stimulated or excited is called a resting cell and it is polarized it is more negative on the inside than on the outside
When the cell is stimulated Gates of the cell membrane open which allows sodium ions in the ions are positively charged so the cell becomes more positive when the cell is more positive it is called depolarized
The cell cannot accept another stimulus until it returns to its resting state in this time period when it cannot accept another stimulus it is called the refractory period
When potassium gates open and potassium leaves taking its positive charge with it this is called repolarization and the inside of the cell becomes more negative again
They are all or nothing meaning the depolarization always finishes and is always the same size
Sodium ions move into neurons during action potential
An excitable cell is one that can change its membrane potential
During hyperpolarization a cell becomes more negative than when resting
Membrane potential is a separation of charge across the membrane |
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Local potentials |
Size of the stimulus determines the excitement of the cell It is how your CNS determines the size the environmental change Local potentials vary in size depending on the stimulus |
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Neurotransmitters |
Special chemicals used to send a signal across the synapse Bind to the cell receiving the signal opening or closing the gate The last step in transfer of information is removing the neurotransmitter from the synapse to prevent it from binding to the receiving cell
This type of synapse is called a chemical synapse because neurotransmitters carry the information from one cell to another
Used to send signals across synapses
When released from the presynaptic neuron it binds to the postsynaptic cell |
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Electrical synapses |
Transfer information freely because they have special connections called Gap Junctions Found in the intercalated discs between cardiac muscle fibers |
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Spinal cord and spinal nerves |
Spinal cord is located in a hollow tube running inside the vertebral column
There are Thirty-One segments each with a pair of spinal nerves named for the corresponding vertebrae
The spinal cord ends at L2 in a pointed structure called the conus medullaries
Hanging from the conus medullaries is the cauda equina or horses tail, spinal nerves which dangle Loosely and float in a bath of cerebral spinal fluid
The spinal cord has two widen the cervical and Lumbar enlargements which contain the neurons for the upper and lower limbs
Ventral root carries motor information and dorsal root carries sensory information
The ascending spinal cord tracts are sensory
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Meninges |
Protective covering of both the brain and spinal cord they help to set up layers as cushioning and shock absorbers Dura mater is the outer layer of thick fibrous tissue Arachnoid mater composed of collagen and elastic fibers contains CSF fluid and acts as shock absorber
Pia mater is fused to surface of Cns contains blood vessels that serve the brain and spinal cord |
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Spinal nerves |
31 pairs of spinal nerves each name for the spinal cord segments which they are attached A nerve consists of bundles of axon blood vessels and connective tissues
Spinal nerves are mixed nerves which means they carry both sensory and motor information all spinal nerves are mixed
Plexus are complex branching patterns |
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Reflexes |
Simplest form of motor output you can make Reflexes are generally protective and involuntary Can occur without your brain being involved involving only your spinal cord |
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Common disorders |
Peripheral neuropathy can be non genetic such as disease trauma and infection Symptoms include muscle weakness decreased reflexes numbness tingling paralysis pain and difficulty controlling blood pressure Spinal trauma cervical injury may result in quadriplegic and if the diaphragm is paralyzed the individual can't breathe on their own Thoratic spinal cord damage causes of lower paraplegic patient can move their arms Guillian Barre syndrome - rapid onset paralysis caused by inflammation of peripheral nerve Myasthenia gravis- autoimmune disorder which attacks and destroys acetylcholine receptors at the neuromuscular Junction Eye muscles muscles are usually the first affected Botulism- form of paralysis caused by toxins produced by the bacteria clostridium botulinum Caused by ingesting the toxin in food or from a wound infection Incorrect food canning Meningitis is an infection from either a virus or bacteria of the meninges The bacteria infect the upper respiratory tract and then travel to the mingies Viral meningitis is a much milder version of the disease Carpal tunnel syndrome is an inflammation and swelling of the tendon sheath surrounding the flexor tendon of the Palm Median nerve is compressed producing tingling sensation or numbness of the palm and the first three fingers |
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Axons |
Fastest is large myelinated
Myelinated aka white matter
Columns are axon Pathways for carrying information up and down the spinal cord
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Internal anatomy of the spinal cord |
The spinal cord is divided in half by a ventral median fissure and a dorsal medium sulcus Fissure is a deep groove on surface Sulcus shallow groove on surface Interior of spinal cord is divided into sections of white matter columns and gray matter horns Dorsal horn is involved in sensory functions Ventral horn is involved in motor functions Lateral horn is involved in autonomic functions Dorsal column tract carries fine touch and vibration information to the cebral cortex Spinothalamic track carries temperature pain and crude touch information to the cebral cortex Spinocerebellar tract carries information about posture and position to the cerebellum Several descending Pathways carry motor information which are orders for voluntary movements from the brain to the spinal cord Corticospinal tract Carrie's orders from the brain to the motor neurons in the ventral Horn of the spinal cord Corticobulbar tract carries orders from the brain to motor neurons in the brain stem Reticulospinal and rubrospinal tracts carry information from the brain to the brainstem and ventral horn which helps coordinate movements Commissures connect left and right halves of the cord so the two sides of the CNS can communicate Spinal Roots projecting from both sides of the spinal cord in pairs fuse to form spinal nerves Ventral root carries motor information Dorsal root ganglion is in the dorsal root it is a collection of sensory neurons and carries sensory information |
