physiology cram

This cram sheet focuses on the high-yield topics identified from your lecture and the specific question style (functional localization, clinical pathology, and mechanics) found in your sample MCQs.

### 1. Functional Localization: The "Final Relay" & Vital Centers

Exams frequently ask you to identify the specific brain region responsible for a task.

* Thalamus: The final relay point for all sensory information (except smell) on its way to the primary somatosensory cortex [1-3].

* Hypothalamus: The center for homeostasis; regulates hunger, thirst, and body temperature. It secretes ADH (which decreases urinary output) and Oxytocin [1, 4].

* Medulla Oblongata: Contains vital centers for cardiovascular (heart rate/blood pressure) and respiratory (breathing pace) control [5].

* Cerebrum:

* Broca’s Area: Motor speech (frontal lobe) [6].

* Wernicke’s Area: Language comprehension (temporal/parietal junction) [6].

* Primary Motor Cortex: Located in the precentral gyrus; initiates voluntary movement [6, 7].

### 2. Clinical Pathology: Consequences of Damage

MCQs often present a symptom and ask which structure is damaged.

* Damage to the Cerebellum: Results in ataxia and inaccurate movements (dysmetria); the cerebellum fine-tunes timing but does not initiate movement [7-9].

* Damage to the Vestibulospinal Tract: Leads to disorders of balance, coordination, and nystagmus (repetitive eye movement) [10, 11].

* Substantia Nigra (Dopamine Loss): Decreased dopamine leads to increased muscle tone and rigidity (Parkinsonian symptoms) [12].

* Upper Motor Neuron Syndrome: Result of damage to the corticospinal tract [13].

### 3. Motor Tract Mechanics (Descending Pathways)

* Corticospinal Tract: The highest order of motor function for fine, digital movements [13].

* 90% Decussate (cross over) at the pyramids of the medulla to form the Lateral Corticospinal Tract [7].

* 10% stay on the same side as the Anterior Corticospinal Tract [7].

* Rubrospinal Tract: Originates in the Red Nucleus; modulates flexor muscle tone in the upper limbs [14].

* Vestibulospinal Tract: Originates in the vestibular nucleus; maintains upright posture and head-eye coordination [15].

* Reticulospinal Tract: Originates in the reticular formation; manages posture, balance, and autonomic functions [13, 14].

### 4. The Cellular Environment & Neural Propagation

* **Resting Membrane Potential:** -70mV; the cell is polarized (Positive outside/Na+; Negative inside/K+ and Proteins) [16].

* Saltatory Propagation: Rapid conduction where the action potential skips the myelin-covered internodes and depolarizes only at the Nodes of Ranvier [17].

* Neuroglia:

* **CNS:** Oligodendrocytes (myelin), Astrocytes (blood-brain barrier), Microglia (immune) [18].

* **PNS:** Schwann cells (myelin), Satellite cells (support) [16].

### 5. The Vestibular System: Detecting Motion

* Otolith Organs: Detect linear acceleration.

* Utricle: Horizontal plane [19].

* Saccule: Vertical plane [19].

* Semicircular Canals: Detect rotational acceleration [19].

* Endolymph: The fluid within the labyrinth is unique: High K+, low Na+ [20].

### 6. Quick-Fire Exam Facts

* CSF Production: Created by ependymal cells in the choroid plexus at ~500 mL/day [6, 21].

* Meninges Order: (Outer) Dura → Arachnoid → Pia (Inner) [21].

* Cranial Nerve II: The Optic nerve (special sensory for vision) [10, 22].

* Cranial Nerve X: The Vagus nerve; a mixed nerve controlling visceral organs in the thorax and abdomen [10].

* Cranial Nerve Mnemonic: "Oh Once One Takes The Anatomy Final Very Good Vacations Are Heavenly" [10].

I can also create a tailored report containing this information if you would like a formatted document to download and print for your final "cram" session. Would you like me to do that?