Nervous System Flashcards
A communication system that helps coordinate the body functions to maintain homeostasis; carries signals from the brain to the rest of the body
Nervous System
Division of Nervous System
CNS and PNS
Consists of the brain and spinal cord
Central Nervous System
Consists of all the nervous tissue outside the CNS, inc. nerves & ganglia
Peripheral Nervous System
Functions of Nervous System
Maintaining Homeostasis, Establishing & Maintaining Mental Activity, Receiving Sensory Input…
Cells that comprise the nervous system is the type of tissue that called
Nervous Tissue
Forms the brain, spinal cord and nerves
Nervous Tissue
What makes up the nervous tissue
Neurons and Glial Cells
Three parts of Neurons
Cell Body, Dendrites and Axon
Support cells and noursih, protect and isulate neurons
Glial Cells
Receive stimuli, conduct action potentials and transmit signals to other neurons or effector organs
Neurons
Part of neuron that conducts electrical signals; at the base of axon where it joins the cell body and travel to the axon’s end
Axon
Usually receive information from other receptors and transmit it toward the neuron cell body
Dendrites
Contain a single Nucleus and is the source of info for gene expression
Cell Body
“perikaryon” or soma; contains a singke nucleus; site of gen.cell functions
Cell Body
Maintains the neuron’s structure, resp. for protein synthesis and source of info for gene expression
Function of Cell Body
Are short, highly branching cytoplasmic extensions; present at the end of a neuron; most are extensions of the neuron cell body
Dendrites
Receive information from other neurons or from other sensory receptors; transmit information toward the neuron cell body
Function if Dendrites
Singke long cell process extending from the cell body; has uniform diameter and may vary in length; can be surrounded by myelin sheaths
Axon
Conduct Action Potential, Electrical Signals
Functions of Axon
Area where the axon leaves the neuron cell body
Axon Hillock
The end of axon
Axon Terminals (presynaptic terminals)
Gaps in the myelin sheaths
Nodes of Ranvier
Axons may remain unbranched or branched to form____?
Collateral Axons
Axons with myelin sheaths
Myelinated Axons
Lack the myelin sheaths
Unmyelinated Axons
Pseudo-Unipolar Neuron, Bipolar Neuron, Multipolar Neuron
Structural Types of Neurons
Have a single process extending from the cell body
Pseudo-Unipolar Neuron
Have two processes: one dendrite and one axon
Bipolar Neuron
Have many dendrites and a single axon
Multipolar Neuron
Desc: Appears to have a singe axon
Func: most sensory neurons
Pseudo-Unipolar
Desc: one dendrite and one axon
Func: found in special sense organs (eye and nose)
Bipolar
Desc: many dendrites and one axon
Func: most motor neurons and most CNS neuron
Multipolar
Sensory Neurons, Interneurons, Motor Neurons
Functional Tyoes of Neurons
Sends sensory info to CNS- brain and spinal cord; AFFERENT(toward) the brain
Sensory neurons
Connects sensory neuron to the motor neuron
Interneurons
Carry messages from the brain to allow us to move muscles; EFFERENT (away) from the brain
Motor Neurons
Don’t conduct action potentials; Retain ability to divide; carry out diff activities that enhance neuron function and maintain normal conditions
Glial Cells
How many Types of Glial Cells are there?
4 CNS and 2 PNS
CNS Glial Cells
Astrocytes, Ependymal Cells, Oligodendrocytes, Microglia
PNS Glial Cells
Satellite Cells, Schwann Cells
Star shaped cells; largest and most numerous of the neuroglia
Astrocytes
Functions of Astrocytes
Provide structural support, regulate neuron signalinh, contribute to blood-brain barrier, help with tissue repair
Cuboidal to columnar cells; possess microvilli and cilia
Ependymal Cells
Functions of Ependymal Cells
Line ventricles of the brain and central canal of the spinal cord; circulate cerebrospinal fluid(CSF); some form choroid plexuses which produce CSF
Small, mobile cells, dedicated to the brain’s immune cells
Microglia
Functions of Microglia
Protect CNS from Infection; become phagocytic in response to inflammation
Resemble astrocytes but are smaller and contain fewer processes; cells with processes that can surround several axons
Oligodendrocytes
Form myelin sheaths around axons or enclose unmyelinated axons in the CNS, help info move faster
Functions of Oligodendrocytes
Myelination
Myelin Sheath and Unmyelinated
Multilayered lipid and protein covering some axons
Myelin Sheath
Axons without coverings
Unmyelinated
Functions of Myelination
Insulates the axon of a neuron, increases the speed of nerve impkuse conduction
Single cells surrounding axons; form myelin sheath around axons
Schwann Cells
Functions of Schwann Cells
Form myelin sheaths around axons, participate in axon regeneration
Single flay cells that surround cell bodies in PNS ganglia
Satellite Cells
Functions of Satellite Cells
Provides structural support, nutrients; protect neurons from heavy-metal poisons
Consists of grps of neuron bodues and their dendrites, where there is little myelin
Gray Matter
Gray Matter on the surface of the brain in CNS
Cortex
Gray Matter located deeper within the brain
Nuclei
A cluster of nueron cell bodies in the PNS
Ganglion
Consists of bundles of parallel axons with their myelin sheaths
White Matter
White matter of the CNS forms ____ which propagate acrion potentials from one area of CNS to another
Nerve Tracts; (or conduction pathways)
Two Simplest Pathways
Converging Pathway and Diverging Pathway
Two or more neurons synapse with the same postsynaptic neuron; allows info transmitted in more than one neuronal pathway to converge into a singel one
Converging Pathway
Axon from one neuron divides and synapses with more than one other postsynaptic neuron; allows info transmitted in one pathway to diverge into two or more pathways
Diverging Pathway
Three Columns of Spinal Cord
Dorsal Column, Ventral Column, Lateral Column
Neuronal pathway by which a reflex occurs
Reflex Arc
Simplest reflex
Stretch Reflex
Classic example of stretch reflex; clinicians used this to determine if the higher CNS centers that influence this reflex is functional
Knee-jerk Reflex
To remoce a limb or another body oart from a painful stimulus
Withdrawal Reflex (flexor relfex)
Spinal nerves contqin axons of both sensory and somatic motor neurons called___?
Mixed Nerves
Three Major Plexuses of the Spinal Nerves
Cervical Plexus, Branchial Plexus and Lumbosacral Plexus
Suppies the motor innervation to the smooth muscles of the pelvic floor and sensory xutaneous innervation to the skin over the coccyx
Coccygeal Plexus
Originates from the C1-C4; its branches inneevate sev.muscles attached to the hyoid bone
Cervical Plexus
One of the most important branches of cervical plexus; innervates the diagram- resp. for ability to breathe
Phrenic Nerve
Orginates from C5-T1; Five major nerves emerge here to supply the upper limb and shoulder
Brachial Plexus
Innervates two shoulder muscles; skin innervates- part of shoulder
Axillary Nerve
Posterior arm & forearm muscles (extensors); skin- posterior arm, forearm and hand
Radial Nerve
Anterior arm muscles(flexors); skin- radial surface of forearm
Musculocutaneous Nerve
Two anterior forearm muscles(flexors), most intrinsic hand muscles; skin- ulnar side of hand
Ulnar Nerve
Most anterior forearm muscles (flexors), some intrinsic hans muscles; skin- raidal side of hand
Median Nerve
Originates fromL1-L4; four major nerves exit here to supply the lowerlimb
Lbosacral Nerve
Medial Thigh muscles(adductors); skin- medial thigh
Obturator Nerve
Anterior thigh muscles(extensors); skin- anterior thigh, medial leg and foot
Femoral Nerve
Posterior thigh muscles(flexors), anterior & posterior leg muscles, most foot muscles; skin- posterior leg and sole of foot
Tibial Nerve
Lateral thigh and leg, some foot muscles; skin- anterior & lateral leg, dorsal(top) part of foot
Common Fibular Nerve
Emerge S5 & C0; lateral thigh and leg, some foot muscles; skin- skin over coccyx
Coccygeal Plexus
Brachial Nerve
Axillary, Radial, Musculocutaneous, Ulnar, Median
Cervical Nerve
Phrenic
Lumbosacral Nerve
Obturator, Femoral, Tibial, Common Fibular
Major regions of Brain
Medulla Oblongata, the Pons , and Midbrain
Most inferior portion of the brain and continuous with the spinal cord
Medulla Oblongata
Two prominent enlargements on the anterior surface of the medulla oblongata; transmit A.Potentials to the somayic motor neurons and are involved in the continuous control of skeletal muscles
Pyramids
Superiorbto the medulla oblongata; some nerves relay info between cerrbrum and cerebellum
Pons
The smallest region of the brainstem
Midbrain
Four mounds of tissue in midbrain; two are major relay centers for auditory nerve pathways, other two involved in visual reflexes, receive touch and auditory input
Colliculi
Attached to the brainstem by several large connections; involved in maintaing balance & muscle tone and coordinating fine motor movement
Cerebellum
Part of the brain betweenthe brainstem and cerebrum
Diencephalon
Largest part of the brsin
Cerebrum
Lobe of hemisphere importqntvin the control of voluntary motor functions, moticwtion, agrrssion, mood and semllbreception
Frontal Lobe
Principsl center for receiving and consciously perceiving most sensory info- touch, pain, temp and balance
Parietal Lobe
Functs in receiving and perceiving visual input
Occipital Lobe
Involved in Olfa tory and Auditory sensations; play important role in memory
Temporal Lobe
Fifth Lobe, involved in perception of taste
Insula
EEG
Electroencephalogram
Aurround and protect the brain and spinal cord
Meninges
Number of Cranial Nerves
12
Cranial Nerve I; receives info from the nose
Olfactory
Cranial Nerve II; receives info from eye, transmits the vision to the brain
Optic
Cranial Nerve III; transmit motor info to move eye muscles
Oculomotor
Cranial Nerve IV; transmit motor info to move eye muscles(superior oblique muscle)
Trochlear
Cranial Nerve V; three-branched nerve, transmit both sensory info from and motor info to the head
Trigeminal
Cranial Nerve VI; motor nerve, moves eye(lacteral rectus muscle)
Abducens
Cranial Nerve VII; receives sensory info from the anterior tongue and takes motor info to the head muscles
Facial
Cranial Nerve VIII; receives info from ear, transmits equilibrium and acoustic info
Vestibulocochlear
Cranial Nerve IX; mixed nerve to the musvles of the neck, moves head
Glossopharyngeal
Cranial Nerve X; receives info from abdomen, thorax, neck and root of tongue
Vagus
Cranial Nerve XI; motor nerve to the muscles of neck; moves the head
Accessory
Cranial Nerve XII; motor nerve to rhe tongue
Hypoglossal
Branch of Trigeminal that passes through superior orbital fissure
Opthalmic Branch
Branch of Trigeminal that passes through foramen rotundum of the sphenoid bone
Maxillary Branch
Branch of Trigeminal that passes through foramen ovale of the sphenoid bone
Mandibular Branch
Fight-or-flight division of the ANS; prepares a person for physical activity
Sympathetic Division
Rest-and-Digest of the ANS; gen.consistent with resting conditions
Parasympathetic Division
