Chapter 13 - The Brain and Cranial Nerves

Comprehensive practice flashcards covering brain anatomy, embryonic development, meninges, ventricles, cerebral functions, and cranial nerves based on the Chapter 13 lecture notes.

According to the glossary of nervous system structures, what is the definition of 'Gray matter cortex'?

The superficial layer of gray matter in the brain.

What is the difference between a 'Tract' and a 'Nerve' according to Table 13.2?

A tract is a bundle of axons within the CNS that share a common origin and destination, whereas a nerve is a bundle of axons in the PNS.

What are the three primary brain vesicles formed during embryonic development at 4 weeks?

Prosencephalon (forebrain), Mesencephalon (midbrain), and Rhombencephalon (hindbrain).

Into which adult brain regions does the Rhombencephalon (hindbrain) differentiate via its secondary vesicles?

The Metencephalon becomes the pons and cerebellum (superior part), and the Myelencephalon becomes the medulla oblongata.

Which adult neural canal derivative is associated with the Diencephalon?

The third ventricle.

What are the three cranial meninges listed from deepest (innermost) to most superficial?

Pia mater, Arachnoid mater, and Dura mater.

Describe the composition and adherence of the Pia mater.

It is a thin layer of delicate areolar connective tissue that tightly adheres to the brain, following every contour of its surface.

Where is the subarachnoid space located and what does it contain?

It is located deep to the arachnoid mater (between the arachnoid and pia mater) and contains cerebrospinal fluid (CSF).

What are 'dural venous sinuses'?

Large, blood-filled spaces formed where the periosteal and meningeal layers of the dura mater separate.

What is the primary function of the cranial dural septa?

They are double layers of dura mater that separate specific parts of the brain and provide stabilization and support.

How does an epidural hematoma differ from a subdural hematoma in terms of blood source and expansion rate?

An epidural hematoma involves rapidly expanding arterial blood (often from a torn middle meningeal artery), while a subdural hematoma involves slowly expanding venous blood (often from a torn bridging vein).

What cells line the brain ventricles and what fluid do they contain?

They are lined with ependymal cells and contain cerebrospinal fluid (CSF).

How is Cerebrospinal Fluid (CSF) formed?

It is formed by the choroid plexus from blood plasma filtered from capillaries and modified by ependymal cells.

How does the chemical composition of CSF compare to blood plasma regarding ion concentrations?

CSF contains more $Na^+$ and $Cl^-$, and less $K^+$ and $Ca^{2+}$ than blood.

Trace the flow of CSF from the lateral ventricles to the subarachnoid space.

Lateral ventricles → interventricular foramen → third ventricle → cerebral aqueduct → fourth ventricle → lateral and median apertures → subarachnoid space.

Which glial cell is primarily responsible for forming the blood-brain barrier (BBB) by wrapping perivascular feet around capillaries?

Astrocytes.

What is 'cerebral lateralization'?

The phenomenon where the two cerebral hemispheres, while mirror images, display functional differences, such as speech control usually being located in the left hemisphere.

What are the primary functions of the frontal lobe?

Higher intellectual functions (concentration, decision making, planning), personality, verbal communication, and voluntary motor control of skeletal muscles.

Where is the primary somatosensory cortex located and what is its function?

It is located within the postcentral gyrus of the parietal lobe and is responsible for the sensory interpretation of textures and shapes.

What is the specific function of the Broca area (motor speech area)?

Production of speech, specifically the control of the tongue and airway.

Distinguish between association tracts, commissural tracts, and projection tracts in the central white matter.

Association tracts connect regions within the same hemisphere; commissural tracts extend between hemispheres (e.g., corpus callosum); projection tracts link the cortex to inferior brain regions and the spinal cord.

What is the function of the Thalamus?

It acts as the 'relay station' for all conscious sensory information (except olfaction) to the primary somatosensory cortex.

Which part of the diencephalon houses the 'thirst center' and the 'thermostat'?

The Hypothalamus (specifically the anterior nucleus for thirst and the preoptic area for temperature).

What hormone is secreted by the pineal gland in the epithalamus to help regulate circadian rhythm?

Melatonin.

What are the three main regions of the brainstem?

Midbrain, Pons, and Medulla oblongata.

What is the function of the 'arbor vitae' found in the cerebellum?

It is the inner white matter of the cerebellum that coordinates fine control over skeletal muscle actions.

Which cranial nerve (number and name) is responsible for vision?

CN II, the Optic nerve.

Which cranial nerve provides taste sensation to the anterior two-thirds of the tongue?

CN VII, the Facial nerve.

Name the tenth cranial nerve (CN X) and identify its primary visceral sensory function.

The Vagus nerve; it carries visceral sensory information from the heart, lungs, and most abdominal organs.

Which cranial nerve is motor only and controls tongue movement?

CN XII, the Hypoglossal nerve.