Structure and Development of NS III

Diencephalon

Brain region containing the thalamus and hypothalamus that regulates sensory relay, homeostasis, and endocrine function

Thalamus

Major sensory relay center where nearly all sensory information (except olfaction) is processed before reaching the cortex

Hypothalamus

Controls homeostasis, endocrine function, and motivated behaviors (eating, drinking, sex) and regulates the pituitary gland via the HPA axis

HPA axis

Hormonal pathway where hypothalamus signals the pituitary, which signals the adrenal glands to regulate stress and body responses

Midbrain

Brain region involved in vision, hearing, and reward processing

Superior colliculus

Midbrain structure that processes visual information and reflexive eye movements

Inferior colliculus

Midbrain structure that processes auditory information

Ventral tegmental area (VTA)

Midbrain region involved in reward and dopamine signaling

Hindbrain

Includes pons, medulla, and cerebellum; controls basic life functions and movement coordination

Pons

Regulates motor and sensory functions as well as sleep and arousal; contains pathways connecting cortex to cerebellum

Medulla

Controls essential life functions such as heart rate and breathing

Cerebellum

Responsible for motor learning, coordination, and fine-tuning movements

Meninges

Three protective layers (dura, arachnoid, pia) surrounding the CNS that protect and support the brain

Subarachnoid space

Space between arachnoid and pia filled with CSF for cushioning and nutrient/waste exchange

Blood-brain barrier (BBB)

Selective barrier that protects the brain from harmful substances in the blood

Ventricles and CSF system

Network of fluid-filled spaces in the brain where cerebrospinal fluid (CSF) is produced, circulated, and drained

Cerebrospinal fluid (CSF)

Fluid similar to plasma that cushions the brain, delivers nutrients, and removes waste

Choroid plexus

Structure in ventricles that filters blood to produce CSF

CSF flow

CSF is produced from arterial blood in ventricles → flows through brain → enters subarachnoid space → waste drains into venous system

Arterial vs venous roles in CSF

Arteries supply blood to make fresh CSF, veins remove waste from CSF

Structural brain imaging

Techniques that show brain anatomy

MRI

Uses magnetic fields and hydrogen atoms to produce detailed images of brain structure

DTI

MRI-based technique that tracks water movement to visualize white matter tracts

Functional brain imaging

Techniques that measure brain activity

PET

Uses radioactive glucose or oxygen to measure metabolic activity, which reflects neural activity

fMRI

Measures changes in blood flow to identify active brain regions and functional circuits