OTHED 1505 Week 1: Key Terms/ Acquisition Questions

Nervous System

The body's communication network that controls voluntary and involuntary actions, transmitting signals between the brain, spinal cord, and body. Components: CNS (brain + spinal cord) and PNS (cranial + spinal nerves)

Application Question: If someone touches a hot stove and quickly pulls their hand away, which two main divisions of the nervous system are working together to make this response happen?

Answer: The Peripheral Nervous System (PNS) detects the pain and sends it to the Central Nervous System (CNS), which processes the signal and sends a motor command back to the muscles.

Central Nervous System (CNS)

Brain and spinal cord; processes information and initiates responses.

Peripheral Nervous System (PNS)

: All nerves outside the CNS, including cranial and spinal nerves; connects CNS to the body.

If you step on a tack, which division of the nervous system carries the pain message to your spinal cord and brain?

The sensory nerves of the PNS carry the pain message to the CNS.

If your physical therapist says your pain is "distal to the knee," where is the pain located in relation to the knee?

The pain is below or farther away from the trunk than the knee, such as in the shin or foot.

Anterior (ventral)

front of the body

Posterior (dorsal)

back of body

superior (cephalic)

toward the head

Inferior (caudal)

away from the head end or toward the lower part of a structure or the body; below

Medial

Toward the midline of the body

Lateral

Away from the midline of the body

Proximal

Nearer to the trunk of the body

Distal

Farther from the trunk of the body

Frontal Lobe

Motor control, problem solving, planning, speech production (Broca's area).

Parietal Lobe

Sensory processing, spatial awareness.

Temporal Lobe

Hearing, memory, emotion; contains hippocampus & amygdala.

Occipital Lobe

Vision processing.

Insular Cortex

Pain, taste, emotion, homeostasis.

Cerebrum

Largest brain part; higher brain functions.

If someone has difficulty speaking and planning movements, which lobe of the brain is most likely damaged?

The frontal lobe

Neuron

Functional unit of the nervous system that transmits signals.

What is a neuron and its main structures?

A neuron is a nerve cell that sends and receives signals.

• Dendrites: Receive signals.

• Cell body (soma): Processes signals.

• Axon: Sends signals to other neurons or muscles.

• Myelin sheath: Covers axon for faster signal transmission.

• Axon terminals: Release neurotransmitters to communicate.

Neuron Structures

Dendrites = receive signals, Cell body (soma) = processes info, Axon = sends signals, Axon terminals = release neurotransmitters.

If a neuron cannot send signals to the next cell because neurotransmitters are not released, which part of the neuron is malfunctioning?

The axon terminals.

White Matter

Myelinated axons; fast signal transmission.

Gray Matter

Neuron cell bodies; information processing.

Explain the difference between white matter and gray matter.

White matter: Made of myelinated axons; transmits signals quickly.

Gray matter: Made of cell bodies and dendrites; processes information.

If a disease causes damage to myelin, which type of matter is affected and how might it impact communication speed in the nervous system?

White matter is affected, causing slower or blocked signal transmission (like in multiple sclerosis).

Cranial Nerve I (name, sensory or motor, function)

Olfactory

Sensory

Smell

Cranial Nerve II (name, sensory or motor, function)

Optic

Sensory

Vision

Cranial Nerve III (name, sensory or motor, function)

Oculomotor

Motor

Eye movement, pupil constriction

Cranial Nerve IV (name, sensory or motor, function)

Trochlear

motor

eye movement (superior oblique)

Cranial Nerve V (name, sensory or motor, function)

Trigeminal

Both

Face sensation, chewing

Cranial Nerve VI (name, sensory or motor, function)

Abductens

Motor

Eye movement (lateral rectus)

Cranial Nerve VII (name, sensory or motor, function)

Facial

Both

Facial expression, taste

Cranial Nerve VIII (name, sensory or motor, function)

Vestibulocochlear

Sensory

Hearing, balance

Cranial Nerve IX (name, sensory or motor, function)

Glossopharyngeal

Both

Swallowing, taste

Cranial Nerve X (name, sensory or motor, function)

Vagus

Both

Parasympathetic control, swallowing, speech

Cranial Nerve XI (name, sensory or motor, function)

Accessory

Motor

Shoulder and neck muscles

Cranial Nerve XII (name, sensory or motor, function)

Hypoglossal

Motor

Tongue movement

Spinal Nerve Pathways : Ascending

Ascending (Sensory): Dorsal root → CNS; carries sensory info to the brain.

Explain the pathway of ascending and descending spinal nerves.

Ascending spinal nerves: Carry sensory information from the body → spinal cord → brain. They enter through the dorsal root.

Descending spinal nerves: Carry motor commands from the brain → spinal cord → body. They exit through the ventral root.

Afferent neurons (sensory neurons)

Carry sensory information from the body's periphery (e.g., skin, eyes, ears) to the central nervous system (brain and spinal cord

Efferent neurons (motor neurons)

Carry motor commands from the central nervous system to the body's muscles and glands

Ascending sensory pathway

The pathway likely damaged if a patient cannot feel sensations in their foot.

Spinal Nerve Pathways: Descending

(Motor): Brain → CNS → ventral root → muscles; carries motor commands.

Dermatomes (definition and function)

Skin area supplied by a single spinal nerve.

Function: Sends sensory info to the somatosensory cortex; helps identify nerve injury levels.

Dermatome mapping

The tool that could help identify which spinal nerve may be injured if a patient has numbness along their thumb and index finger.

Myotomes (definition and function)

Muscle groups supplied by a single spinal nerve.

Function: Receives motor commands from the primary motor cortex; helps assess motor function.

Myotome mapping

The type of mapping that would help identify the affected spinal nerve if a patient cannot lift their wrist.

What is an important component of each spinal cord level?

Cervical: Controls neck, arms, hands, breathing (diaphragm).

Thoracic: Controls trunk and abdominal muscles.

Lumbar: Controls legs and lower body.

Sacral: Controls bowel, bladder, sexual function.

Spinal Reflex Arc / Withdrawal Reflex

Definition: Automatic response to stimuli for protection. Pathway: Sensory receptor → sensory neuron → interneuron → motor neuron → effector (muscle).

Spinal reflex arc

The type of nervous system response that occurs when you accidentally step on a sharp object and immediately lift your foot.

Explain a spinal reflex arc/withdrawal reflex and why it is important.

Reflex arc: Automatic, fast response that doesn't require the brain.

Example: Touching something hot → sensory neuron → spinal cord → motor neuron → pull hand away.

Importance: Protects the body and helps clinicians assess nervous system function.

Upper Motor Neuron (UMN)

Brain → spinal cord; damage causes spastic paralysis (Ex: stroke, multiple sclerosis).

Lower Motor Neuron (LMN)

Spinal cord → muscles; damage causes flaccid paralysis (Ex: Bell's palsy).

Difference between upper motor neurons (UMN) and lower motor neurons (LMN) give an example of each

UMN: Located in brain and spinal cord; damage causes spasticity and hyperreflexia.

Example: Stroke, Multiple Sclerosis.

LMN: Connect spinal cord to muscles; damage causes flaccidity and hyporeflexia.

Example: Bell's Palsy, Peripheral Nerve Injury.

Difference between upper motor neurons (UMN) and lower motor neurons (LMN) + examples.

UMN: Located in brain and spinal cord; damage causes spasticity and hyperreflexia.

Example: Stroke, Multiple Sclerosis.

LMN: Connect spinal cord to muscles; damage causes flaccidity and hyporeflexia.

Example: Bell's Palsy, Peripheral Nerve Injury.

Upper Motor Neuron (UMN) damage

The type of motor neuron that is damaged if a patient has spastic paralysis in their right arm after a stroke.

Corticospinal tract

Motor: Voluntary movement - Descending, sends signals from brain to muscles

Spinothalamic tract

Sensory: Pain & temperature -Carries pain, temperature, and touch sensations to the brain

Dorsal Column-Medial Lemniscus tract

Sensory: Fine touch & proprioception - Ascending, Carries vibration, pressure, and proprioception information to the brain.

Limbic System

Emotion & memory

Hippocampus

Memory formation

Amygdala

Emotion processing.

Brainstem

Heart rate, breathing, reflexes.

Thalamus

Sensory relay center.

Hypothalamus

Homeostasis, hormone regulation.

Dorsal Root Ganglia

Sensory neuron cell bodies outside CNS.

Motor Pathways

Descending; brain → muscles.

Sensory Pathways

Ascending; body → brain.

Motor pathway damage

The pathway affected if a patient cannot move their leg but can still feel touch in it.