Module 6 : Nervous System Flashcards
Cells of the Nervous System Neurons
Neuron Structure
- Cell body of the neuron
- Dendrites
- Axon
Types of Neurons
- Sensory (afferent) neurons
- Motor (efferent) neurons
- Interneurons
Cells of the Nervous System: Glia (Neuroglia)
Central Glia
- Astrocytes
- Microglia
- Oligodendrocytes
Peripheral Glia
- Schwann Cells
~Myelin
~Nodes of Ranvier
~Neurilemma
nerves : nerves and tracts
Nerve coverings
- Endoneurium, perineurium, epineurium
White and gray matter
Nerves: Nerve signals
Reflex arcs
- receptor > ganglion > synapse > effector > reflex
~neurotransmitters
~two neuron arc and three neuron arc reflexes
CNS : Brain
divisions of the brain
- Brainstem
~medulla oblongata, pons, and midbrain
- Cerebellum
- Diencephalon
~Hypothalamus, thalamus, and pineal gland
- Cerebrum
Brainstem
Centre of vital functions
- medulla oblongata
- pons
- midbrain
Structure
- Reticular formation
Functions
- two-way conduction paths
Cerebellum : Structure
Lies under the occipital lobe of the cerebrum
- gray matter> info processing
- white matter > arbor vitae
Cerebellum: Functions
- helps control muscle contractions to produce coordinated movements for maintaining balance, moving smoothly, and sustaining normal postures
- Coordinating effects with cerebrum and other regions of the brain
Diencephalon
Hypothalamus> major control centre for the ANS
- Controls hormone secretion by anterior and posterior pituitary glands
- Controls body temp, appetite, wakefulness, and pleasure
Thalamus
- sensory info relay; sensation and emotion association; level of consciousness regulation; complex reflex movements
Pineal Gland
- Melatonin regulation in maintaining body’s timeclock
Cerebrum
Structure
- cerebral cortex
- gyri, sulci, fissures
- tracts
- Basal nuclei/basal ganglia
Functions
- consciousness, thinking, memory, sensations, emotions, and voluntary control of movements
CNS : Spinal Cord
Structure
white matter composed of myelinated nerve fibers (outer)
Gray matter composed of neuron dendrites and cell bodies (inner)
CNS : spinal cord
Functions
primary centre for all spinal cord reflexes
Two-way conduction paths to and from the brain
- Ascending spinal cord tracts
- descending spinal cord tracts
Coverings and fluid spaces of the CNS
Meninges and bone
- cranial bones and vertebrae
- cerebral and spinal meninges
~dura mater, arachnoid mater, pia mater
Cerebrospinal fluid spaces (CSF)
- subarachnoid spaces and meninges
- central canal inside spinal cord
- Ventricles in brain
Peripheral nervous system
Cranial nerves (12 pairs)
- connects brain with the neck and structures in the thorax and abdomen
Spinal nerves (31 pairs)
- contain dendrites of sensory neurons and axons of motor neurons
- conduct impulses necessary for sensations and voluntary movements
Dermatomes
- Skin surface area supplied by a single cranial or spinal nerve
Autonomic Nervous system : functional anatomy
Autonomic neurons
- preganglionic and postganglionic neurons
Autonomic conduction pathways
- two-neuron relays
Somatic Motor neurons
- voluntary control
- involuntary control
- somatic and special senses sensory input
autonomic conduction pathways Sympathetic division
Structure:
- preganglionic neurons located in lateral horns of gray matter in the 12th thoracic and first two lumbar segments of the spinal cord
- Sympathetic ganglia lie in two chains on either side of the vertebral column
Function:
- Emergency/stress system controlling visceral effectors
- fight or flight response
Autonomic conduction pathways parasympathetic division
Structure:
- located in brainstem nuclei and lateral gray matter of the 2nd through 4gh segments of the spinal cord
- each parasympathetic preganglionic neuron synapses with postganglionic neurons to only one effector
Functions:
- control of many visceral effectors under normal, everyday conditions
- counterbalance to sympathetic function
Glossary: Action potential
Nerve impulse
Glossary: Adrenergic fiber
Any of the axons whose terminals release norepinephrine and epinephrine
Glossary: Afferent neuron
neuron that conducts impulses toward the central nervous system; generally a sensory neuron
Glossary: Amine
a category of chemical neurotransmitters
Glossary: Anesthesia
loss of sensation
Glossary: Antidiuretic hormone (ADH)
Hormone produced in the posterior pituitary gland to regulate the balance of water in the body by accelerating the reabsorption of water
Glossary: Arachnoid mater
Delicate, cobweblike middle membrane (meninx) covering the brain
Glossary: Astrocyte
a type of neuroglial cell found in the brain and spinal cord
Glossary: Autonomic nervous system (ANS)
division of the human nervous system that regulates involuntary actions
Glossary: Autonomic effector
tissues to which autonomic neurons conduct impulses
Glossary: Autonomic neuron
motor neurons that make up the autonomic nervous system
Glossary: Axon
nerve cell process that transmits impulses away from the cell body
Glossary: Basal ganglia (sing. basal ganglion)
Also known as basal nucleus
Glossary: basal nuclei (sing. basal nucleus)
a group of islands of gray matter located in the base of the cerebrum that are responsible for autonomic movements and postures
Glossary: Blood brain barrier (BBB)
two-ply structure formed by the wall of a capillary and the surrounding extensions of a glial cell called an astrocyte; functions to prevent harmful chemicals from entering vital brain tissue
Glossary: Cell body
The main part of a neuron from which the dendrites and axons extend
Glossary: Central Nervous system (CNS)
portion of the nervous system that includes the brain and spinal cord
Glossary: Cerebellum (pl. cerebella or cerebellums)
The second largest part of the human brain that plays an essential role in the production of normal movements
Glossary: Cerebral cortex
a thin layer of gray matter, made up of neuron dendrites and cell bodies, that composes the surface of the cerebrum
Glossary: Cerebrospinal fluid
fluid that fills the subarachnoid space in the brain and spinal cord and the cerebral ventricles
Glossary: Cerebrum
the largest and uppermost part of the human brain that controls consciousness, memory, sensations, emotions, and voluntary movements
Glossary: Cerebrovascular accident (CVA)
A hemorrhage or cessation of blood flow through cerebral blood vessels resulting in destruction of neurons; commonly called a stroke
Glossary: Cholinergic fibers
axon whose terminals release ACh
Glossary: Choroid plexus (pl. choroid plexuses)
A network of brain capillaries that are involved with the production of cerebrospinal fluid
Glossary: Corpus callosum (pl. corpora callosa)
Where the right and left cerebral hemispheres are joined
Glossary: Cranial nerve
any of 12 pairs of nerves that attach to the undersurface of the brain and conduct impulses between the brain and structures in the head, neck, and thorax
Glossary: Dendrite
branchin or treelike; a nerve cell process that transmits impulses toward the body
Glossary: Dermatome
Any of the skin surface areas supplied by a single spinal nerve
Glossary: Diencephalon
“between” brian; parts of the brain between the cerebral hemispheres and the mesencephalon or midbrain
Glossary: Dura mater
literally “strong or hard mother”; outermost layer of the meninges
Glossary: Dopamine
chemical neurotransmitter
Glossary: Efferent neurons
neuron that transmits impulses from the CNS to the periphery; opposite (in direction) of afferent neuron
Glossary: Effector
responding organ; for ex. voluntary and involuntary muscles, the heart, and glands
Glossary: Endoneurium
The thin wrapping of fibrous connective tissue that surrounds each axon in a nerve
Glossary: Endorphine
any of a group of chemicals in the CNS that influence pain perception; a natural painkiller