Chapter 13

What are the main components of the Central Nervous System (CNS)?

Brain and Spinal cord

What do the directional terms "Rostral" and "Caudal" mean in the CNS?

Rostral: Toward the nose (front)

Caudal: Toward the tail (back)

Used to describe anatomical locations, especially in four-limbed animals.

What basic functions does the brain control?

Vital body functions: heart rate, respiratory rate, blood pressure

Regulates: Autonomic Nervous System (ANS), Controls Endocrine System (hormone secretion)

Involved in peripheral innervation via cranial nerves (12 pairs) and spinal nerves (31 pairs), which are part of the Peripheral Nervous System (PNS)

What are some higher-level neural functions of the brain?

Intelligence, consciousness, memory, sensory-motor integration, emotion, behavior, socialization

What is cephalization?

The formation and growth of the head and brain during embryonic development, starting from the rostral part of the neural tube.

What are the primary brain vesicles and what do they develop into?

Prosencephalon (Forebrain): divides into Telencephalon and Diencephalon

Mesencephalon (Midbrain): remains undivided

Rhombencephalon (Hindbrain): divides into Metencephalon and Myelencephalon

What is convolutions, gyri and sulci, and why are they important?

Convolutions: folds of the brain that increase surface area and neural communication 

Gyri: raised ridges

Sulci: grooves between gyri
They increase the brain’s surface area, allowing more neurons and improved neural communication.

Match these secondary brain vesicles to their adult brain structures:

Telencephalon

Diencephalon

Mesencephalon

Metencephalon

Myelencephalon

Telencephalon → Cerebral hemispheres (Cerebrum)

Diencephalon → Thalamus, Hypothalamus, Epithalamus

Mesencephalon → Midbrain

Metencephalon → Pons and Cerebellum

Myelencephalon → Medulla Oblongata

What are the major functions of the Telencephalon (Cerebrum)?

Largest brain region; responsible for complex thought, cognition, consciousness, and empathy.

Where is Diencephalon located and their functions?

Thalamus: sensory relay

Hypothalamus: homeostasis and endocrine regulation

Epithalamus: contains pineal gland (melatonin production and circadian rhythms)

What are the main functions of the Mesencephalon (Midbrain)?

Part of brainstem; involved in visual and auditory reflexes, and motor pathways.

What are the functions of the Metencephalon (Pons and Cerebellum)?

Pons: communication bridge between brain regions

Cerebellum: coordination, balance, and motor control; second largest brain region.

What autonomic functions does the Myelencephalon (Medulla Oblongata) control?

Breathing, heart rate, and blood pressure.

Summary of Development Pathway

1. Neural tube (Week 4, embryonic structure) 

2. → Three primary brain vesicles 

3. → Five secondary brain vesicles .

4. → Adult brain structures 

What structures make up the brainstem, and what are its general functions?

Midbrain, Pons, Medulla Oblongata

• Passageway for fiber tracts between cerebrum and spinal cord

• Innervates face and head (motor and sensory)

• Houses 10 of the 12 cranial nerves

• Controls automatic survival behaviors: breathing, heart rate, digestion

• Integrates visual and auditory reflexes (especially midbrain)

What are brain ventricles and what do they contain?

Fluid-filled spaces derived from the neural tube’s central cavity, containing cerebrospinal fluid (CSF) which protects, nourishes, removes waste, and maintains intracranial pressure.

What happens during rapid brain growth in embryonic development?

The brain grows quickly; different regions develop and expand at varying rates.

What are the roles of gray and white matter in the brain?

Gray Matter: Neuronal cell bodies; involved in processing & integration

White Matter: Myelinated axons; provides communication pathways

How do brain structures shift during development?

Cerebral hemispheres grow larger and eventually surround the diencephalon and midbrain, making them mostly hidden in the adult brain.

What are the four major brain regions?

Brainstem – midbrain, pons, medulla oblongata

Cerebellum – coordination, balance, motor control

Diencephalon – thalamus, hypothalamus, epithalamus

Cerebral Hemispheres (Cerebrum) – higher cognitive functions

Where is gray matter found in the brain?

Deep regions (central core)

Outer layer (cortex) of the cerebrum and cerebellum

Where is white matter found, and what is its function?

Surrounds deep gray matter; allows communication between brain regions through nerve tracts.

What is the cortex in brain tissue?

The outer layer of gray matter found in the cerebrum and cerebellum, formed by neuron migration during development.

What is cerebrospinal fluid (CSF), and what are its functions?

Filtered from blood by choroid plexuses

Functions: Shock absorption,  Nutrient delivery, Waste removal

What are the ventricles of the brain and their locations?

Lateral Ventricles: In cerebral hemispheres (horseshoe-shaped)

Third Ventricle: In diencephalon

Fourth Ventricle: In hindbrain (between pons and cerebellum)

Cerebral Aqueduct: Narrow channel through midbrain connecting 3rd and 4th ventricles

How does CSF flow through the ventricular system?

Lateral ventricles
→ Interventricular foramina
→ Third ventricle
→ Cerebral aqueduct
→ Fourth ventricle
→ Central canal of spinal cord & subarachnoid space

What is Midbrain (mesencephalon)

Develops from the mesencephalon (embryonic brain vesicle) 
Functions: Controls eye motor movement, Processes visual and auditory information

Part of brainstem, located between forebrain and hindbrain