Week Three Flashcards
Peripheral Nervous System (Cranial and Spinal Nerves)
What does the PNS connect?
The CNS to the limbs and organs
What is a main role of the CNS?
Relaying info between the body and the brain
Essential for sensory data input and motor data output
What is the CNS composed of?
Nerves (bundles of axons) and ganglia (neuronal cell bodies)
What is ganglia?
Relay points in the nervous pathway
Processing centres
What are the types of peripheral nerves?
Sensory nerves
Motor nerves
Mixed nerves
What is a sensory nerve?
Carry information from the body to the brain and spinal cord
What is a motor nerve?
Send messages from the brain and spinal cord to the body (primarily for muscle contraction and movement)
What is a mixed nerve?
Contain both sensor and motor fibres, so they can do both jobs
How many cranial nerves are there?
12 pairs
What are cranial nerves essential for?
Sensory and motor function of the head and neck
How many spinal nerves are there?
31 pairs, each associated with a spinal cord segment
What are spinal nerves essential for?
Motor (movement), sensory (feeling), and autonomic (automatic body functions) signals
Each nerve innervates a specific body region
What are the 3 sensory cranial nerves?
Olfactory (smell)
Optic (vision)
Vestibulocochlear (hearing/balance)
What are the 5 motor cranial nerves?
Oculomotor (eye movement)
Trochlear (eye movement)
Abducens (eye movement)
Accessory (neck and head movement)
Hypoglossal (tongue movement)
What are the 4 mixed cranial nerves?
Trigeminal (facial sensation, chewing)
Facial (taste, facial expression)
Glossopharyngeal (tongue + pharynx movement, swallowing)
Vagus (abdomen, swallowing, chewing)
What is a mnemonic to remember the ordering/numbering of the cranial nerves?
Obviously: Olfactory
Only: Optic
Octopus: Ocularmotor
Try: Trochlear
To: Trigeminal
Attract: Abducens
Fish: Facial
Via: Vestibulocochlear
Giving: Glossopharyngeal
Very: Vagus
Awesome: Accessory
Head: Hypoglossal
What is a mnemonic to remember which cranial nerves are motor, sensory, and mixed?
Some
Say
Money
Matters
But
My
Brother
Says
Big
Brains
Matter
More
What is the functional significance of cranial nerves?
Vital for daily life activities like seeing, tasting, hearing, and facial expressions
Damage to these nerves can lead to significant disabilities such as vision loss, speech difficulties, or impaired balance
What are the cranial nerves related to speech production? (6)
CNV (trigenimal): activates muscles for mastication (chewing), impacts articulation
CNVII (facial): controls facial expressions (lip movement), essential for articulation
CNIX (glossopharyngeal): movement of the pharynx
CNX (vagus): movements in the larynx, pharynx, and velum
CNXI (accessory): vital for respiration
CNXII (hypoglossal): controls tongue movements: crucial for consonant and vowel production
How many of each type of spinal nerves are there?
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
What is the function of the cervical spinal nerves?
Innervate the neck, shoulders, arms, and hands
What is the function of the thoracic spinal nerves?
Control chest, certain abdominal muscles, and mid-back
What is the function of the lumbar and sacral spinal nerves?
Innervate lower abdomen, legs, bowel, and bladder
What is the phrenic nerve?
Spinal nerves C3, C4, C5
Crucial for breathing, primarily innervating the diaphragm (for contraction)
What are afferent nerves?
Sensory nerves
Sensory information enters in the dorsal root
What are efferent nerves?
Motor nerves
Motor information exits in the ventral root
What are skeletal muscles composed of?
Muscle fibres, connective tissue, blood vessels and nerves
What are the parts within a whole muscle?
Whole muscle
Fascicles
Muscle fiber
Myofibril
Sacromere
Actin (thin)
Myosin (thick)
What is the basic unit where muscle contraction occurs?
Sacromere
Sliding filament theory
What is the mechanism of muscle contraction?
Myosin head will attach to actin and then bend, as it bends it will slide (pull) against the length causing the muscle to contract (become shorter), and then it will release
What is a motor unit?
Single motor neuron and all the muscle fibres it innervates/controls
Take turns activating to not tire out
