Chapter 13

Meninges

Three protective membranes (dura mater, arachnoid mater, pia mater) surrounding the brain and spinal cord

Dura Mater

Tough, outermost meningeal layer; has two layers in the brain: periosteal and meningeal

Venous Sinuses

Spaces between dura mater layers that collect venous blood and drain into the jugular veins

Arachnoid Mater

Middle meningeal layer; web-like and loose-fitting; contains arachnoid villi

Subarachnoid Space

Space between arachnoid and pia mater; filled with CSF

Arachnoid Villi

Projections of arachnoid mater that reabsorb CSF into venous sinuses

Pia Mater

Thin, vascular meningeal layer that tightly adheres to the brain surface

Cerebrospinal Fluid (CSF)

Clear fluid cushioning and supporting the brain; produced by choroid plexuses

Choroid Plexus

Network of capillaries and ependymal cells that filter blood to produce CSF

Ventricles

Hollow cavities in the brain that contain CSF (lateral, third, fourth)

Central Canal

A narrow channel that extends into the spinal cord, allowing CSF flow

Interventricular Foramen

Channel connecting each lateral ventricle to the third ventricle

Cerebral Aqueduct

Connects third and fourth ventricles; passes through the midbrain

Blood-Brain Barrier (BBB)

Protective barrier formed by endothelial cells, basement membrane, and astrocytes

Tight Junctions

Structures that seal endothelial cells in brain capillaries, restricting permeability

Cerebral Hemispheres

The two halves of the brain (left and right)

Cerebral Cortex

Outer gray matter layer involved in consciousness, perception, and voluntary movement

White Matter

Inner brain region of myelinated axons for communication

Gyri

Raised ridges on the brain surface

Sulci

Shallow grooves between gyri

Fissures

Deep grooves separating brain regions

Precentral Gyrus

Location of the primary motor cortex

Postcentral Gyrus

Location of the primary somatosensory cortex

Broca’s Area

Motor speech area; controls muscles for speech (usually left hemisphere)

Wernicke’s Area

Language comprehension area (usually left hemisphere)

Prefrontal Cortex

Responsible for personality, decision-making, social behavior

Primary Visual Cortex

Receives visual input; located in occipital lobe

Primary Auditory Cortex

Processes sound; located in temporal lobe

Olfactory Cortex

Processes smell; located in medial temporal lobe

Association Fibers

Connect regions within the same cerebral hemisphere

Commissural Fibers

Connect the two hemispheres (e.g., corpus callosum)

Projection Fibers

Connect cerebral cortex to lower brain/spinal cord centers

Thalamus

Relay station for sensory input to the cerebral cortex

Hypothalamus

Maintains homeostasis; regulates autonomic functions, hormones, and emotional responses

Infundibulum

Stalk connecting the hypothalamus to the pituitary gland

Pituitary Gland

Endocrine gland regulated by the hypothalamus; secretes hormones like GH, ADH, and oxytocin

Homeostasis

Maintenance of a stable internal environment

Autonomic Control Center

Function of the hypothalamus that regulates heart rate, digestion, and body temperature