Unit I Review Flashcards
What are the anatomical components of the central nervous system?
Brain and spinal cord
What are the anatomical components of the peripheral nervous system?
All neural tissue outside of the CNS
What is the difference between spinal nerves and cranial nerves?
Point of origin
What type of information is carried by the afferent division of the PNS?
Sensory information
What type of information is carried by the efferent division of the PNS?
Motor commands
What is the difference between the somatic and autonomic nervous systems?
We have control over somatic system, which is skeletal muscle.
Most sensory neurons of the PNS are this type of neuron
Unipolar neuron
All motor neurons control skeletal muscle are this type of neuron
Multipolar neuron
Where are chemically gated sodium channels located on a neuron?
For the most part, the dendrites and cell body
What are the characteristics of Type A, Type B, and Type C fibers?
Type A - Largest myelinated axons, and fastest at approximately 268 mph
Type B - Smaller myelinated axons, traveling approximately 40 mph
Type C - Unmyelinated and slow, traveling only 2 mph
What are the main characteristics of excitatory and inhibitory neurotransmitters
Excitatory - Cause depolarization and promote action potentials
Inhibitory - Cause hyperpolarization and suppress action potentials
Explain the main events at a cholinergic synapse
- Action potential arrives at the presynaptic terminal
- Voltage-gated calcium channels open, and Ca2+ rushes in cause the release of ACh
- ACh diffuses across the synaptic cleft and binds to receptors on the postsynaptic terminal, causing chemically-gated Na+ channels to open resulting in a graded depolarization
- ACh is broken down into acetate and choline by AChE, and the choline is reabsorbed by the axon terminal to make more ACh.
What is the role of norepinephrine
Released at adrenergic synapses, has an excitatory effect. Found in portions of the ANS
What is the role of dopamine
May have inhibitory or excitatory effects. It inhibits muscle movements to prevent over-stimulation. Without dopamine Parkinson’s disease develops. In some areas of the brain, it causes excitatory effects.
What is serotonin
Affects attention and emotional states
What is GABA
Not fully understood. Generally inhibitory and used in some anti-anxiety medications.
What is nitric oxide
Generated by axon terminals that innervate smooth muscle in the walls of blood vessels.
What are neuromodulators
Alter the rate of release of neurotransmitters or change the postsynaptic response
What are the four classes of opioids and what are their primary functions?
- Endorphins
- Enkephalins
- Endomorphins
- Dynorphins
Primary use is to relieve pain by inhibiting release of substance P at pain synapses
What are postsynaptic potentials
Graded potentials that develop at the postsynaptic membrane
What is an EPSP
A graded depolarization caused by the arrival of a neurotransmitter at the postsynaptic membrane
What is an IPSP
A grade hyperpolarization of the postsynaptic terminal. For example, could result from the opening of chemically-gated K+ channels.
What is temporal summation?
Additional stimuli occurring in rapid succession at a single synapse
What is spatial summation?
Stimuli arrive simultaneously at different locations, causing a cumulative effect on the membrane potential.
Explain the role of GABA and Serotonin in presynaptic inhibition/facilitation
GABA and Serotonin can block or activate (respectively) the Ca+ channels of the synaptic terminal. With GABA, less Ca+ results in less ACh which results in inhibition, and vice versa for Serotonin.
(Chapter 13)
What type of nerve are spinal nerves classified as and why?
Mixed nerves, because they contain both sensory and motor fibers (afferent and efferent)
Where is the epidural space?
Between the dura mater and the walls of the vertebral canal
What fluid can be found in the subarachnoid space?
Cerebrospinal fluid
What is a dermatome? What is the clinical importance of dermatomes?
The specific bi-lateral skin surface monitored by a single pair of spinal nerves. The clinical importance is that damage or infection of a spinal nerve or dorsal root ganglion will produce a loss of sensation in the corresponding region monitored by that nerve.
What are the four nerve plexuses
Cervical, Brachial, Lumbar, Sacral
What areas of the body are innervated by the cervical plexus
Neck and thoracic cavity. The phrenic nerve is the major nerve of the cervical plexus.
What areas of the body are innervated by the brachial plexus?
Pectoral girdle and upper limb
What is the major nerve of the lumbar plexus?
Femoral nerve
What is the major nerve of the sacral plexus?
Sciatic nerve
What are the five steps in a simple neural reflex
- Arrival of a stimuli
- Activation of sensory neuron
- Information processing in the CNS
- Activation of a motor neuron
- Response by a peripheral effector
What is a somatic reflex?
Reflex involving involuntary movement of skeletal muscle
What is a visceral reflex?
Reflexes involving systems other than skeletal muscle
What is a cranial reflex? Give an example.
A reflex which is processed in the brain, such as the blinking and swallowing reflexes.
What is reciprocal inhibition
When a reflex causes the flexors contract, it also causes the extensors relax, or when the extensors contract, the flexors relax, etc.
What is an ipsilateral reflex arc?
A reflex where motor output happens on the same side of the body as the stimulus was detected
What is a contralateral reflex arc?
A reflex where the motor output occurs on the opposite side of the body as the stimulus was detected
(Chapter 14)
What is contained in the ventricles of the brain?
Cerebrospinal fluid
What are the three largest dural folds
Falx cerebri, tentorium cerebelli, falx cerebelli
What are the functions of cerebrospinal fluid (CSF)?
Cushioning/Protection, supporting the brain, transport nutrients/chemicals/waste
What is the role of arachnoid granulation in the circulations of CSF?
They allow CSF to be absorbed into venous circulation
What is the reticular formation
Extends from the medulla oblongata to the midbrain and receives input from cranial nerves, cerebral cortex and the brain stem. Its output controls many autonomic functions.
What are the two respiratory centers contained within the reticular formation of the pons?
Apneustic and Pneumotaxic
What are the two primary functions of the cerebellum
Adjust posture muscles and fine-tine motor movements
What are the functions of the superior and inferior follicular of the midbrain?
Integrate visual (upper) and auditory (lower) information with other sensory input
What is the major function of the substantia nigra?
Regulates basal nuclei activity
What structures make up the diencephalon
Thalamus and Hypothalamus
What role does the thalamus play in relaying sensory information to the primary sensory cortex?
It filters sensory information before sending it to the primary sensory cortex
What two hormones are produced by the hypothalamus?
Antidiuretic hormone and Oxytocin
What are the functions of the limbic system
- Establish emotional states
- Link conscious thought with autonomic functions
- Facilitate memory storage and retrieval
What is the role of the amygdaloid body of the limbic system
Links emotions and memories and plays a role in some autonomic functions, including fight or flight
What is the main function of the hippocampus
Important in learning, including storage and retrieval of long-term memories
What are the main functions of the basal nuclei?
Subconscious control of skeletal muscle and coordination of learned movement patterns
What are the main structures of the basal nuclei
Caudate nucleus, lentiform nucleus, globus pallidus, putamen
Which areas of the brain receive the sensations from the special sense organs?
Each has its own area: visual cortex, gustatory cortex, etc.
What is the function of association areas of the brain?
Interpret incoming sensory data and formulate a motor response
What are integrative areas in the brain
Receive information from several different areas and coordinate complex motor activities, such as the speech center
What is another name for the speech center of the brain and what is its function
Broca’s area. It regulates patterns of breathing and vocalizing for speech.
What functions are chiefly processed in the left hemisphere of the cerebrum?
General interpretive, speech center, and language-based skills
What functions are chiefly processed in the right hemisphere of the cerebrum?
Sensory information processing, including analyzing emotional context.
(Chapter 15)
What are the general senses?
Temperature, pain, touch, pressure, vibration, and proprioception
What are free nerve endings?
Non-specific nerves that permeate through the skin like roots and are receptive to all types of stimuli
What are tonic receptors?
Receptors which are always active
What are physic receptors?
Receptors which are usually NOT active. Provide feedback on intensity and rate-of-change of a stimulus
What are exteroceptors
Provide feedback about the external environment
What are proprioceptors
Provide feedback about the position of the body
What are interoceptors
Monitor visceral organs and functions
What are nociceptors
Pain receptors
How are fast pain and slow pain sensations transmitted?
Fast pain: Type A myelinated fibers
Slow pain: Type C unmyelinated fibers
How do endorphins and enkephalins reduce the level of pain that a person feels?
Bind to Substance P (a neurotransmitter) receptors to block pain
What structures in the brain receive temperature sensations?
Reticular formation, thalamus, primary sensory cortex
What are the three classes of mechanoreceptors
Tactile receptors, baroreceptors, proprioceptors
What are the three major groups of proprioceptors
Muscle spindles, Golgi Tendon Organs, receptors in joint capsules
What are first-order neurons
Sensory nerves that delivery sensory information to the CNS
What are second-order neurons
Interneurons
What are third-order neurons
Second-order neurons synapse on third-order neurons in the THALAMUS
What are the three major somatic sensory pathways
Spinothalamic pathway, posterior column pathway, spinocerebellar pathway
What types of sensations are carried by the anterior spinothalamic tract
Crude touch and pressure
What types of sensations are carried by the lateral spinothalamic tract
Pain and temperature
What types of sensations are carried by the posterior column pathway
Proprioception, fine touch, vibration, (ventral pressure)
What types of sensations are carried by the spinocerebellar pathway
Proprioception input from Golgi tendon organs, muscle spindles, and joint capsule receptors
Where can chemoreceptors be found
Carotid arteries, arch of the aorta, cerebrospinal fluid
What is the corticospinal pathway
Pathway for nerves which provide voluntary control of spinal muscles
Why do patients with Parkinson’s disease have problems with voluntary control of movement?
Excitatory neurons within the basal nuclei become more active than the inhibitory neurons (which normally release GABA)
(Chapter 16)
What are preganglionic neurons
VISCERAL motor neurons in the brain stem and spinal cord (note: somatic motor neurons are classified as upper and lower)
What are ganglionic neurons
Visceral motor neurons in the peripheral ganglia
What are the characteristics of sympathetic vs parasympathetic preganglionic and ganglionic neurons
Parasympathetic preganglionic neurons are much longer, and the ganglionic neurons are very short. Sympathetic preganglionic neurons are shorter and synapse at sympathetic chain ganglia
What are collateral ganglia
Innervate tissues and organs in the abdominopelvic cavity (part of the sympathetic division)
What are adrenal medullae
When stimulated, they release their neurotransmitters into the bloodstream, which then act as hormones
Explain the properties of Alpha 1 Receptors
- Adrenergic receptors (NE, E)
- Found in smooth muscle of peripheral blood vessels
- Causes vasoconstriction of peripheral blood vessels
Explain the properties of Alpha 2 Receptors
- Adrenergic receptors (NE, E)
- Found in neuromuscular and neuroglandular junctions of the parasympathetic division
- Causes an inhibitory response
Explain the properties of Beta 1 Receptors
- Adrenergic (NE, E)
- Found in skeletal muscles and cardiac muscles
- Causes an excitatory response (increased HR and metabolism)
Explain the properties of Beta 2 Receptors
- Adrenergic (NE, E)
- Found in smooth muscle of the bronchioles
- Cause the bronchioles to relax
Explain the properties of Beta 3 Receptors
- Adrenergic (NE, E)
- Found in adipose tissue
- Causes lipolysis (breakdown of fat for use by skeletal muscles)
What are synapses that use ACh as a neurotransmitter called?
Cholinergic
What are synapses that release NE and E called
Adrenergic
What is NO and what is its role in sympathetic stimulation
Nitric oxide. It is released where neurons innervate a large volume of blood vessels, notably skeletal muscle. It causes vasodilation for increased blood flow during sympathetic activation.
What are the two types of ACh (cholinergic) receptors
Nicotinic and muscarinic
What is dual innervation
Organs innervated by both the sympathetic and parasympathetic divisions
What is the consensual light reflex? Which division of the ANS is involved in this reflex?
Constriction of both pupils when a light in shone in one. Parasympathetic division.
What is the pupillary reflex? Which division of the ANS is involved in this reflex?
Your pupils dilate in the dark. Sympathetic division.
What are fact memories?
Specific pieces of information, such as the color of something or the smell of a perfume
What are skill memories
Learned motor behaviors
What are short-term memories
Similar to RAM. Short-lasting, but can be recalled instantly.
What is memory consolidation
Converting short-term memories to long-term memories
What are secondary memories
Long-term memories that fade over time
What are tertiary memories
Long-term memories that are with you for a lifetime, such as your name.
What is the role of the hippocampus in memory
Essential for memory consolidation
What is the role of the amygdala in memory
Links memories to emotions
Where are most long-term memories stored
In the cerebral cortex
Where are motor memories stored
Premotor cortex
Which part of the brain plays a role in arousal from sleep
Reticular activating system (RAS) in the reticular formation area of the brain
