Cranial and Spinal Nerves Lecture Flashcards

General Overview of Cranial and Peripheral Nerves

Cranial Nerves in the Peripheral Nervous System (PNS): * Special emphasis is placed on Cranial Nerve $10$ , known as the Vagus nerve ( $V-a-g-u-s$ ). * The instructor notes that memorizing everything immediately is not necessary, but students must know at least number $10$ .
Brain Protection and Recovery: * Exercise: It is stated that exercise protects the brain through the blood-brain barrier. * Alcohol Effects: Recovery from the effects of alcohol on the brain takes a long time. * Schwann Cells: These cells have a nucleus positioned very close to the outside, allowing the $DNA$ to replicate significantly.

Educational Methodology and Study Resources

Textbook and PowerPoints: * The primary resource is the FA Davis ebook. * Instructor PowerPoints: These are specifically for instructors and contain questions and answers; however, they are aligned with the student ebook. The student PowerPoints differ slightly from the teacher's versions. * Study Strategy: The instructor suggests treating the textbook as a "bedtime story" and referencing it constantly. Reading summaries alone is insufficient as it misses the "essence" of the information. * Visual Learning: Students are encouraged to look at pictures and diagrams in the text before coming to class. Highlighting text in the digital version may provide simplified explanations in a side tab.
Exam Preparation: * Practice Questions: Every chapter in the textbook contains "Test Yourself" questions. For instance, Chapter $11$ contains $18$ questions. * Review Process: Questions will be reviewed in class. If a student takes the test during the review, the instructor may open the test again. * Platforms: Exams are conducted via ATI or Bond (Ambar). * Anklets/NCLEX Practice: Question sets are provided for students to keep and practice for future licensing exams.

Cardiovascular Anatomy Clarification

Valve Identification: * Right Side of the Heart: Contains the Tricuspid valve (mnemonic: "Tri"). * Left Side of the Heart: Contains the Mitral valve (mnemonic: "My").
Blood Flow Path: * Blood enters from the Superior Vena Cava (SVC) into the Right Atrium. * It moves from the Right Atrium into the Right Ventricle. * From the Right Ventricle, blood is pumped out into the Lungs (not the IVC).

The Spinal Cord and Intracranial Pressure

Spinal Cord and Vertebrae Counts: * There is discussion regarding the total number of bones vs. nerves: $33$ , $31$ , $32$ , $26$ , or $25$ . * Infant vs. Adult: A baby may have $33$ bones, but bones fuse as the individual grows, leading to a count of $26$ . * Textbook Specification: The textbook specifically refers to $31$ spinal nerves. * Regional Anatomy: Spinal nerves are categorized by region: * C: Cervical. * T: Thoracic. * Clinical Impact: Injuries at specific levels, such as Cervical $2$ , $3$ , or $4$ ( $C2, C3, C4$ ), will result in localized functional loss (indicated by color-coded diagrams in the text).
Intracranial Pressure (ICP): * Definition: ICP stands for Intracranial Pressure (referred to in the transcript as increased cerebellar pressure). * Causes: Fluid buildup or ruptured blood vessels resulting in blood accumulation in the brain, which causes pressure to increase. This manifests as headaches and other conditions. * Measurement: During a lumbar puncture, healthcare providers must measure the ICP. Simultaneously, a fluid sample is taken and sent to the lab to identify what is growing/occurring inside.

Nervous System Tissue: Gray vs. White Matter

Gray Matter: * Located on the outside (upper part) of the brain. * Contains the cell bodies and forms barriers. * It is described as looking like fat in certain contexts, though it is the outer layer.
White Matter: * Located on the inside of the brain. * Consists of axons. * The white color is attributed to the presence of fat (myelin).

The Autonomic Nervous System (ANS): Sympathetic Division

Function: Prepares the body for physical activity and is responsible for the fight or flight reaction during extreme stress.
Alternative Name: Known as the thoracolumbar division because it arises from the thoracic and lumbar regions of the spinal cord.
Structure: * Preganglionic Neurons: These are short because the ganglia lie in chains close to both sides of the spinal cord. * Fiber Types: Myelinated fibers reach the sympathetic ganglia. Some travel up or down the chain or pass through to other ganglia. * Postganglionic Fibers: These are unmyelinated and tend to be long, extending to target organs. * Response Style: One preganglionic neuron branches and synapses with multiple postganglionic neurons simultaneously, leading to an immediate, widespread response.

The Autonomic Nervous System (ANS): Parasympathetic Division

Function: Produces a calming effect on body functions.
Alternative Name: Known as the craniosacral division because neurons arise from the brain and the sacral region of the spinal cord.
Structure: * Preganglionic Fibers: These are long. * Postganglionic Fibers: These are short because the ganglia reside in or near the target organ. * Response Style: Ganglia are more widely dispersed, resulting in a more localized response compared to the sympathetic division.
Associated Cranial Nerves: * Oculomotor Nerve (Cranial Nerve $3$ ): Carries fibers to the ciliary muscle (thickens the lens of the eye) and the pupillary constrictor (constricts the pupil). * Facial Nerve (Cranial Nerve $7$ ): Regulates tear glands, salivary glands, and nasal glands. * Glossopharyngeal Nerve (Cranial Nerve $9$ ): Triggers salivation. * Vagus Nerve (Cranial Nerve $10$ ): Carries approximately $90\%$ of all parasympathetic preganglionic fibers. It travels to the thoracic cavity (lungs, esophagus, heart) and abdominal cavity (liver, stomach, spleen, pancreas, kidneys, intestine).

Neurotransmitters and Receptors

Neurotransmitters: * Acetylcholine (ACh): Binds to cholinergic receptors. Used by both sympathetic and parasympathetic preganglionic neurons. * Norepinephrine (NE): Binds to adrenergic receptors. Secreted by most postganglionic sympathetic neurons.
Receptor Subtypes: * Cholinergic Receptors: * Nicotinic Receptors: Cells with these receptors are always excited by Acetylcholine. * Muscarinic Receptors: Exhibit variable responses; some are excited and others are inhibited by Acetylcholine. * Adrenergic Receptors: * Alpha-adrenergic Receptors: Most cells with these receptors are excited by norepinephrine. * Beta-adrenergic Receptors: Most cells with these receptors are inhibited by norepinephrine.

Questions & Discussion

Learning and Memory: * The instructor notes that there is no separate "storage space" for memories; everything is a pathway. Consequently, $50\%$ of what is learned can be gone by the next day if not reinforced. * Hemispheres: A brief mention of the left hemisphere controlling the opposite side for motor control and vision.
Student-Teacher Interaction: * Question: "Will you give us a study guide? What will you need us to be focused on?" * Response: The instructor emphasizes that her job is to show "what" to study and "how" to study, not to study for the students. The textbook questions are the primary guide. * Question: "Is the exam going to be on ATI or Bond?" * Response: Questions come from the textbook, but the exam will be taken on the Ambar (Bond) platform. * Student Concern: A student mentioned they find it "offensive" when the instructor calls the material "common sense," noting that everyone learns differently (visual learners vs. reading-focused learners). * Instructor Response: The instructor clarifies that while summaries are names/lists, the textbook provides the comprehensive information and visuals needed for deep understanding.
Specific Chapter $11$ Question Review: * Question $14$ : Characteristic of the somatic nervous system? Answer: D (It operates under voluntary control). * Question $17$ : Answer: E. * Question $18$ : Answer: C. * Mixed Nerve Question: Statement regarding spinal nerves being true? Answer: A (Spinal nerves are mixed nerves containing both sensory and motor fibers).