Nervous System Flashcards
What does the CNS contain?
The brain and spinal cord
The Nervous System contains what two parts?
The Central Nervous system (CNS)
The Peripheral Nervous system (PNS)
What does the middle part of the spinal cord contain?
Gray Matter
What does the spinal cord gray matter resemble in a cross-sectional divide?
A bubbled “H”
What does the anterior horn in the H of the spinal cord do?
Relays motor impulses
What does the posterior gray matter of the H in the spinal cord do?
Relays sensory impulses
What surrounds the H gray matter in the spinal cord?
White matter
What is the function of the white matter in the spinal cord?
It forms ascending and descending tracks.
What three parts does the brain consist of?
It consists of cerebrum (cerebral cortex), the brain stem, and the cerebellum.
What is the function of the brain?
To collect, integrate, and interpret all stimuli; it initiates and monitors voluntary and involuntary motor activity.
What are the meninges?
The three layers that enclose the cerebrum.
What does the meninges contain?
Dura Mater
Arachnoid Mater
Pia Mater
What are the four lobes of the cerebrum?
Parietal
Occipital
Temporal
Frontal
What is the parietal lobe function?
Sensations
Awareness of body shape
What is the occipital lobe function?
Visual stimuli
What is the temporal lobe function?
Hearing
Language
Comprehension
Storage and recall of memories
What is the frontal lobe function?
Personality Judgement Abstract reasoning Social behavior Language expression Movement Speech
What is the function of the cerebellum?
Balance
Coordination
What is the part of the cerebrum that contains the thalamus and hypothalamus and just above the brain stem?
Diencephalon
What important nerves does the brain stem contain?
The cranial nerves 1-12
What is the functional unit of the NS?
Neurons
How many miles of nerves are in the NS?
45
What are the two types of cells in the NS?
Neuroglia and Neurons
What component of the neuron receives impulses inward to the body?
Dendrites
What component of the neuron projects impulses away and may or may not have myelin sheath?
Axons
Contains lipid substance and gives the white color to the white matter of the brain.
Myelin
A multipolar neuron has what?
Cell body
Axon
Multiple dendrites (many poles)
A bipolar neuron has?
Cell body
1 axon
2 dendrites (poles)
A unipolar neuron has?
Cell body
1 axon
1 dendrite (pole)
Transmits nerve impulses towards the CNS from peripheral sensory organs
Afferent
Transmits nerve impulses away from the CNS to muscles, glands, and organs.
Efferent
Conduct impulses from 1 neuron to another
Inter-neurons
What is the purpose of glial cells?
Repair, support, and protect neurons.
Why are glial cells the most common source of primary rumors?
They are mitotic (able to divide and replicate)
What are the 4 types of glial cells?
Oligodendrocytes
Astrocytes
Ependymal
Microglia
The cells produce the myelin sheath that coats the axons.
Oligodendrocytes
These cells are found mostly in gray matter, they accumulate in areas that neurons have been damaged, and feeds the nervous system by the blood brain barrier.
Astrocytes
These cells aide in secretion and regulation of CSF
Ependymal cells
These cells remove waste.
Microglia cells
How fast does nerve impulse conduction travel along the axon and chemical transmission between neurons until it reaches it’s destination?
325mph
What state is the resting state?
No impulse
The resting state has what potassium and what sodium?
Potassium is high
Sodium is low
During depolarization what electrolytes channels open up the cell and enter?
Sodium enters but no change in potassium.
During repolarization what electrolyte channels open up and go back into the cell?
Potassium enters SLOWLY to even out the electrolytes.
What is the conduction system called when the axons are myelinated?
Saltatory Conduction
What is the impulses that reach the end of the nerve fiber then transmit across the junction between nerve cells at the synapse?
Action potential
What are the gaps in the myelin sheath called?
Nodes of Ranvier
What four components does the synaptic transmission involve?
Presynaptic knob
Synaptic cleft
Neurotransmitter
Receptor site
What effects does neurotransmitters have?
Excitability
Inhibitory
What are the four neurotransmitters?
Acetylcholine
Serotonin
Norepinephrine
Dopamine
What three areas does the brain stem contain?
Midbrain
Medulla
Pons
What are the three characteristics of neurons?
Excitability
Conductivity
Influence
The structural and function junction between two neurons.
The synapse
What are the four essential structures of synaptic transmission?
Presynaptic terminal
Synaptic cleft
Neurotransmitter
Receptor site
What are the two types of synapses?
Electrical
Chemical
What is the area where the brain stem exits from the cranial cavity?
Foramen magnum
Which direction does the spinocerebellar tract go?
Ascending
Which direction does the corticospinal tract go?
Descending
What direction is the corticobulbar tracts go?
Ascending to the brain stem
What direction do corticospinal tracts go to
Descending to the spinal cord.
Which area contains Wernicke’s area?
Temporal lobe
Broca’s Area is located in what area?
The frontal lobe
How many pairs of spinal nerves are in the peripheral nervous system?
31
How many cranial nerves are located in the cerebrum?
2
How many cranial nerves are located in the brain stem?
3-12
The outermost protective layer that is fibrous and freely moving?
Scalp
The thickest and toughest outer later of the meninges
Dura Mater
What is the middle layer of the meninges that is thinner and delicate?
Arachnoid
What is the innermost layer that is mesh like and vascular?
Pia Mater
What is the meninges space below the arachnoid and between the pia Mater, where CSF flows?
Subarachnoid
What is the dura fold that separates the 2 cerebral hemispheres?
Falx cerebri
Double dura layer folds between cerebral hemispheres and cerebellum
Tentorium cerebelli
Clear, colorless, odorless fluid; shock absorber; cushions brain and spinal cord against injury. Approximately 135ml of fluid.
Cerebrospinal fluid CSF
CSF doesn’t contain what?
RBCs
Are cauliflower-like and located within the ventricles where CSF is stored and secreted is Astrocytes.
Choroids plexus
What is termed the 3rd circulation?
CSF
What absorbs CSF daily?
Arachnoid villi projections
What gets 20% of cardiac output?
Cerebral circulation
How much of the body’s oxygen and glucose does the brain require?
25%
What doesn’t the brain store?
Minerals
Where do the cerebral veins empty?
Into the dura sinuses.
A unique feature of the valves in the brain.
They have NO valves.
Why is no valves important?
Gravity
Anterior circulation is provided by?
Common carotid from internal and external carotids
Posterior circulation is provided by?
The subclavian artery from two vertebral arteries that merge into basilar arteries.
This structure is a safely valve to protect from pressures and occlusion and can re-route circulation.
Circle of Willis
What is it called when the brain can self regulate it’s blood supply to meet it’s needs by change to the blood vessel diameter.
Auto regulation
Physiological barrier between blood capillaries and brain tissue.
Blood brain barrier.
What is the blood brain barrier made of?
Tight shaped star shaped cells.
What are the folds on the surface of the brain called?
Gyrus
What are deep predictable separations in the brain?
Fissures
What is the outer layer of the brain called (it contains gray matter)?
Cerebral cortex
Just beneath the the cerebral cortex contains?
White matter or myelinated axon tracts
What is contra lateral?
Where the ride side of the frontal lobe controls the left side of the body and vice versa.
What divides the hemisphere of the cerebrum?
Great longitudinal fissure
Cerebral dominancy is located where?
Left frontal lobe
Position in relation to objects around you (comes from the parietal lobe)?
Spatial awareness
Damage to Wernicke’s area where you can ask a question but they may not understand the question asked.
Receptive aphasia
Responsible for fine body movements.
Basal ganglia
This area enables us to form words (located in the frontal lobe).
Brocas Area
System activated under stressful conditions (fight or flight)
Sympathetic
System activated during relaxing situations (rest and digest)
Parasympathetic
This is the relay station for all sensations.
Thalamus
Regulates autonomic nervous system.
Hypothalamus
This is responsible for primal human functions (rage, emotional eating)
Limbic system
What is the primary rhythm center for respirations and heart rate?
Medulla oblongata
In what system does the control of neurons control the sleep-wake cycle called the RAS.
Reticular formation
Extends from C1-L1-L2
Spinal cord
Horse tail look from the spinal column of nerves that exit the spinal cord
Cauda Equina
What is the Monosynaptic Reflex?
Receptor organ to sensory neuron to information processed by the spinal cord to motor neuron
