Anatomy and physiology states

• Understand the detailed structure and function of the brainstem and cerebellum, including specific nuclei clusters and tracts

• Understand cranial nerve pathways, classification, and clinical assessments of their functions.

• Understand the anatomy and physiology of the endocrine system step by step

Understand different disorders of the nervous system (epilepsy, alzheimer’s disease, Parkinson's disease, multiple sclerosis, cerebral palsy, Amyotrophic Lateral Sclerosis) and their impact on neurological function and daily living.

Understand the detailed structured function of the cerebral vasculature, including the internal carotid arteries, vertebral arteries, basilar artery, Circle of Willis, anterior cerebral artery, anterior inferior cerebellar artery and posterior inferior cerebellar artery. Also the treatments and preventions for all conditions listed above. (risk factors, medications, surgical treatment, etc.)

The absolute refractory period is the initial interval during an action potential when a second action potential cannot be initiated, no matter how strong the stimulus. It occurs during depolarization and the first part of repolarization, typically lasting 1–2 ms due to the inactivation of voltage-gated sodium (Na+) channels

This one-pager provides a high-level technical overview of neuroanatomy, endocrinology, and clinical pathology.

1. Brainstem & Cerebellum

The brainstem (Midbrain, Pons, Medulla) serves as the "conduit" for all ascending and descending tracts.

• Brainstem Nuclei: Contains the Reticular Activating System (RAS) for consciousness and the Cardiorespiratory Centers in the medulla.

• Cerebellum: Coordinates movement and motor learning.

  • Structure: Two hemispheres and the central Vermis.

  • Nuclei: Dentate, Emboliform, Globose, and Fastigial (Deep Cerebellar Nuclei).

  • Tracts: Connects via three Peduncles (Superior/Output, Middle/Input from Pons, Inferior/Input from Cord).

2. Cranial Nerves (CN I–XII)

Cranial nerves are classified by function: Sensory (S), Motor (M), or Both (B).

3. The Endocrine System

The endocrine system regulates homeostasis via a hormonal hierarchy:

1. Hypothalamus: The master regulator; releases "Releasing Hormones" (e.g., TRH, CRH).

2. Pituitary Gland: Receives signals to release "Stimulating Hormones" (e.g., TSH, ACTH) into the blood.

3. Target Glands: Thyroid, Adrenals, Gonads, and Pancreas produce effector hormones (Thyroxine, Cortisol, Insulin).

4. Feedback Loop: High levels of effector hormones signal the hypothalamus to stop production (Negative Feedback).

4. Cerebral Vasculature

The brain receives blood from two main sources that converge at the Circle of Willis.

• Anterior Circulation: Internal Carotid Arteries $\rightarrow$ Anterior Cerebral Artery (ACA) and Middle Cerebral Artery (MCA).

• Posterior Circulation: Vertebral Arteries $\rightarrow$ Basilar Artery $\rightarrow$ Posterior Cerebral Artery (PCA).

• Cerebellar Supply:

  • SCA: Superior Cerebellar Artery.

  • AICA: Anterior Inferior Cerebellar Artery (from Basilar).

  • PICA: Posterior Inferior Cerebellar Artery (from Vertebral).

Blood supply of the brain

5. Neurological Disorders: Impacts & Management

General Prevention & Risk Factors

• Risk Factors: Hypertension (Stroke), high cholesterol, sedentary lifestyle, smoking, and genetics.

• Prevention: Blood pressure management, "Heart-Healthy" diet, regular exercise, and cognitive engagement.

• Surgical Interventions: Endovascular coiling (aneurysms), carotid endarterectomy (stenosis), or resection for tumors/seizure foci.

Anatomy and Physiology Notes:

1. Central Nervous System

• Main lobes of the brain and its functions

Frontal lobe + Prefrontal lobe: Controls your movement and judgement

Partial lobe: Controls your senses and your thinking 

Occipital lobe: Controls your vision 

Temporal lobe: Controls your memory and your hearing 

Cerebellum: Controls your balance 

Medula Ablongada: Is the pathway for impulses, reflex, respiration, etc.

• Sections of the spine 

Cervical nerves: Controls shoulders up including arms

Thoracic nerves: Controls the chest 

Lumbar nerves: Controls the legs and feet 

Sacral nerves: Controls the bowel, stomach, etc.

Coccygeal nerves: 

Filum terminale:

• Types of neuroglia in the central nervous system (CNS)

Ependymal cells: They help produce and circulate cerebral spinal fluid

Oligodendrocytes: They insulate axons with a fatty myelin sheath which helps with fast transmission of electrical signals.

Astrocytes: Performs crucial support functions, including maintaining homeostasis, forming the blood-brain barrier and regulating synapses

Microglia: Constantly patrolling the brain to perform several crucial functions. They remove dead cells and waste and they are a part of immune defense

• Brain lateralization 

Left side of the brain: Analytical, the logical side of the brain, controls the right side of the body

Right side of the brain: Creative, controls the left side of the body

In the middle: Cerebral fissure which is used to separate the brain hemispheres, increasing surface area of the brain’s grey matter which is full of neurons, Corpus Callosum is another part of the brain that allows both brain hemispheres to communicate and process faster.

2. Peripheral nervous system

• Cranial Nerves 

Olfactory nerve: Controls smell, central connection to the olfactory bulb, peripheral connection to the olfactory epithelium

Optic nerve: Controls vision, central connection to the hypothalamus, thalamus and midbrain, Peripheral connection to the retina 

Oculomotor nerves: Controls eye movement, central connection to the oculomotor nucleus, peripheral connection to the extraocular muscles 

Trochlear nerves: Controls eye movement, central connection to the trochlear nerves, peripheral connection to the superior oblique muscle

Trigeminal nerves: Controls sensory in your face, central connection to the trigeminal nuclei in the midbrain, pons and medulla, peripheral connections to the Trigemal 

Abducens nerves: Controls eye movements, central connection to the Abducens nucleus, peripheral connection to the Lateral rectus muscle 

Facial nerves: Controls motor facial muscles, central connections to the Facial nucleus, solitary nucleus, superior salivatory nucleus, peripheral connection to the facial muscles, Geniculate ganglion, pterygopalatine ganglion

Auditory (Vestibulocochlear) nerves: Controls hearing and balance, central connection to Cochlearn nucleus, Vestibular nucleus/ cerebellum 

Glossopharyngeal: Controls motor, throat and taste (tongue), central connection to Solitary nucleus, inferior salivatory nucleus, nucleus ambiguus, peripheral connection to Pharyngeal muscles, Geniculate ganglion, Otic ganglion (automonic) 

Vagus: Controls motor and sensory viscera (automonic), Central connection to the medulla, Peripheral connection to the terminal ganglia serving thoracic and upper abdominal organs (Heart and small intestine)

Spinal accessory: Controls motor in head and neck, central connection to the spinal accessory nucleus, peripheral connection to the neck muscles

Hypoglossal: Controls Motor in the lower throat, central connection to the hypoglossal nucleus, peripheral connection to the muscles of the larynx and lower pharynx