Exam 1 Flashcards
- Discuss the general classifications of the nervous system and their primary structures.
- Peripheral: The peripheral nervous system is further subdivided into the somatic nervous system and the autonomic nervous system. cranial nerves, spinal nerves and their roots and branches, peripheral nerves, and neuromuscular junctions.
- Central: Consists of Grey and white matter. Primary structures brain and spinal cord.
- Differentiate the functions of a nerve cell and a glial cell.
Nerve Cells
Transmission of Signals
* Information Processing
* Structural Components
Electrical Activity
* Synaptic Transmission
Glial Cells
Support and Protection
Insulation
Nutrient Supply
Immune Function
Structural Support
- Discuss the state of ions of a neuron at rest and direction of flow for an action potential to transmit and for a message to pass from one neuron to the next.
In the resting state, a neuron is polarized, meaning there is an electrical potential difference across the neuronal membrane. This resting membrane potential is typically around 70 millivolts inside the neuron relative to outside.
Primary ions Na+ & K+
Direction of flow:
Resting Neuron:
* Polarized Membrane: Inside the neuron is negative relative to the outside.
* Key Ions: Sodium (Na+), potassium (K+), and negatively charged proteins (anions).
* Sodium-Potassium Pump: Maintains resting potential by actively transporting ions.
* Potassium Leak Channels: Allow potassium ions to flow out, contributing to negative charge inside.
Action Potential Transmission:
Depolarization Phase:
* Sodium Channels Open: Sodium ions rush in, causing rapid depolarization.
Repolarization Phase:
* Potassium Channels Open: Potassium ions exit, leading to repolarization.
Passage of a Message Between Neurons:
Neurotransmitter Release:
* Action potential triggers release of neurotransmitters.
Synaptic Cleft:
* Neurotransmitters cross the synaptic cleft.
Postsynaptic Neuron:
* Neurotransmitters bind to receptor sites.
* Excitatory or inhibitory signals affect postsynaptic potential.
* If excitatory signals prevail, action potential initiated in postsynaptic neuron.
- Explain the differences between types of graded potentials. These include excitatory post-synaptic potentials (EPSP) and inhibitory post-synaptic potentials (IPSP)
EPSP (Excitatory Post-Synaptic Potential):
* Depolarizing
* Increases the likelihood of an action potential.
* Typically caused by positively charged ions entering the neuron.
* Result of binding of excitatory neurotransmitters to receptors.
IPSP (Inhibitory Post-Synaptic Potential):
* Hyperpolarizing.
* Decreases the likelihood of an action potential.
* Typically caused by negatively charged ions entering the neuron.
* Result of binding of inhibitory neurotransmitters to receptors.
- Describe the type of information transmitted by the five types of sensory receptors discussed.
Mechanoreceptors-Physical stimulation
Photoreceptors-Sight
Nociceptors- Pain
Chemoreceptors- Taste and Smell
Thermoreceptors- Temperature
- Define receptive fields and describe how the relative size the field relates to its purpose and location on the body.
Receptive fields are the area of mechanoreceptors that transmit signals to the brain to identify location of the stimulation. Areas like back, forearms, and thighs have larger fields with less overlap making it more difficult to identify location and quantity of stimulation. Fingers, face, and other highly use areas have smaller fields with more overlap which lead to increased sensation identification.
- Understand the general aspects of the neurological exam
The six areas of testing for a basic neurological exam include:
- Mental Status- client’s level of alertness, orientation (x4 – person, place, time and reason for visit), attention and cooperation
- Cranial Nerves- The cranial nerves are responsible for control facial expression, eye movement, our sense of smell, swallowing, facial sensation, hearing, upper shoulder movement, vocalization and swallowing.
- Motor Exam- observing movement, inspection, palpation, muscle tone testing, functional testing, and strength testing. A main goal of motor testing is simply to identify if a lesion is present in the upper motor neuron or the lower motor neuron
- Reflexes- Reflex Testing involves testing various myotatic reflexes (deep tendons including patellar, Achilles, triceps, biceps, and finger flexors)
- Coordination and Gait- Coordination and Gait testing reveals if an individual has difficulty turning on/off muscles at the same time leading to under or overshooting a target, completing rapid alternating movements, fine motor movements such as finger to nose.
- Sensory Exam- Sensory testing includes sharp/dull, temperature, pain, vibration or position sense.
- Identify the dermatomes and myotomes for the cervical, thoracic, lumbar and sacral spine.
Cervical Spine (C1-C8):
Dermatomes: Skin areas served by cervical nerves.
Myotomes: Muscles primarily controlled by cervical nerves.
Thoracic Spine (T1-T12):
Dermatomes: Cover the torso and upper back.
Myotomes: Primarily refer to intercostal muscles.
Lumbar Spine (L1-L5):
Dermatomes: Skin areas of the lower back, hips, and upper legs.
Myotomes: Include lower back, hip, and thigh muscles.
Sacral Spine (S1-S5):
Dermatomes: Cover the buttocks, perineal region, and backs of the thighs and legs.
Myotomes: Involve muscles in the buttocks, pelvis, hamstrings, and lower limbs.
- Understand the general differences between ASIA A, B, C, D, and E.
ASIA A: Complete injury with no motor or sensory function below the level of injury.
ASIA B: Incomplete injury with sensory function but no motor function below the injury level.
ASIA C: Incomplete injury with some motor function, but most key muscles grade less than 3.
ASIA D: Incomplete injury with significant motor function recovery (most key muscles grade ≥3).
ASIA E: Normal function with no detectable neurological impairments.
- Differentiate between complete and incomplete injuries.
Complete Spinal Cord Injury:
In a complete spinal cord injury, there is a total loss of motor and sensory function below the level of the injury.
Incomplete Spinal Cord Injury:
In an incomplete spinal cord injury, there is some degree of preserved motor or sensory function below the level of the injury.
- Be able to list the locations of synapses and where midline is crossed for the DCML, spinothalamic and corticospinal tracts. Describe what you might see given a various injury in the spine.
DCML Tract
does not cross the midline and synapses in the brainstem.
Spinothalamic Tract
crosses the midline within the spinal cord and is responsible for pain and temperature sensation.
Corticospinal Tract
crosses in the medulla oblongata and controls motor function. Injuries lead to motor deficits on the opposite side of the body.
- Identify the type of information that is carried by each of the above spinal tracts.
DCML (Dorsal Column-Medial Lemniscus) Tract:
Type of Information: Discriminative touch, proprioception (awareness of limb and body position), and vibratory sensation.
Spinothalamic Tract:
Type of Information: Pain and temperature sensation.
Corticospinal Tract (Pyramidal Tract):
Type of Information: Motor commands for voluntary muscle movement.
- Describe the autonomic nervous system processes for regulating blood pressure for a normal (spine intact) person:
- Where is sympathetic versus sympathetic control located to control the heart.
The autonomic nervous system controls the heart. The sympathetic nervous system, located in the thoracic and upper lumbar spinal cord, increases heart rate and contractility. The parasympathetic nervous system, located in the brainstem and sacral spinal cord, decreases heart rate and contractility.
- What happens to HR and BP when each system is in activated (sympathetic and parasympathetic)
Sympathetic: HR BP increase
Parasympathetic: HR BP decrease
- At what levels of injury might you see an unopposed parasympathetic response (i.e. very low resting blood pressure or lack of HR elevation with exercise)
Usually, will see them above C6.
