Central Nervous System (CNS) Lecture Notes

A set of comprehensive flashcards covering key concepts of the Central Nervous System based on lecture notes.

Central Nervous System (CNS)

The primary integration and control center consisting of the brain and spinal cord.

Peripheral Nervous System (PNS)

All neural structures outside of the brain and spinal cord, including sensory receptors and peripheral nerves.

Sensory (Afferent) Division

The functional part of the PNS that carries impulses toward the CNS.

Motor (Efferent) Division

The functional part of the PNS that carries impulses away from the CNS to effector organs.

Somatic Nervous System

A subdivision of the motor PNS responsible for the voluntary control of skeletal muscles.

Autonomic Nervous System (ANS)

A subdivision of the motor PNS responsible for involuntary control of smooth muscle, cardiac muscle, and glands.

Dura Mater

The outermost, toughest layer of the meninges; composed of two dense fibrous layers.

Arachnoid Mater

The middle, web-like layer of the meninges; the subarachnoid space beneath it contains CSF.

Pia Mater

The innermost, delicate layer of the meninges that clings tightly to the surface of the brain and spinal cord.

Choroid Plexuses

Clusters of capillaries within the brain ventricles that produce Cerebrospinal Fluid (CSF).

Functions of CSF

1. Buoyancy: Reduces brain weight by 97\%.

2. Protection: Cushions the brain from trauma.

3. Chemical Stability: Removes metabolic wastes.

Gyrus vs. Sulcus

• Gyrus: An elevated ridge or fold on the cerebral cortex.

• Sulcus: A shallow groove between folds.

Fissure

A deep groove in the brain, such as the longitudinal fissure that separates the two cerebral hemispheres.

Frontal Lobe

Responsible for higher intellectual functions, personality, and voluntary motor control via the Primary Motor Cortex.

Parietal Lobe

Processes general sensory information (touch, temperature, pain) and body orientation.

Temporal Lobe

The primary center for auditory processing, memory, and smell (olfactory) perception.

Occipital Lobe

The primary cortical region designated for visual processing.

Thalamus

The main relay station of the diencephalon; sorts and edits sensory input before sending it to the cortex.

Hypothalamus

The main visceral control center; regulates homeostasis, body temperature, thirst, and the endocrine system.

Epithalamus

Contains the Pineal Gland, which secretes melatonin to regulate the sleep-wake cycle.

Midbrain

Part of the brainstem that contains reflex centers for vision and hearing.

Pons

A brainstem structure that acts as a bridge; it links the cerebrum to the cerebellum and helps regulate breathing.

Medulla Oblongata

The vital center of the brainstem; controls heart rate, blood pressure, and respiratory rhythm.

Cerebellum

Coordinates skilled skeletal muscle movements and maintains balance and posture.

Arbor Vitae

The 'Tree of Life'; the branching internal white matter of the cerebellum.

Broca's Area

Located in the left frontal lobe; controls the motor movements required for speech production.

Wernicke's Area

Located in the left temporal lobe; essential for the comprehension and understanding of written and spoken language.

Reflex Arc Step 1: Receptor

The site where the stimulus is detected.

Reflex Arc Step 2: Sensory Neuron

Transmits the afferent impulse from the receptor to the CNS.

Reflex Arc Step 3: Integration Center

One or more synapses within the CNS (spinal cord or brain) where info is processed.

Reflex Arc Step 4: Motor Neuron

Conducts efficient impulses from the integration center to the effector organ.

Reflex Arc Step 5: Effector

The muscle fiber or gland cell that responds to the initial stimulus.

Sympathetic Division (ANS)

The 'Fight-or-Flight' system; increases heart rate and blood flow to muscles during stress.

Parasympathetic Division (ANS)

The 'Rest-and-Digest' system; conserves energy and promotes maintenance like digestion and urination.

Neuroplasticity

The brain's ability to physically change its structure and function in response to experience, learning, or injury.

Hemispheric Lateralization

The concept that each brain hemisphere has specialized functions (e.g., left for logic/language, right for art/spatial).