Basic Neuroanatomy

Question 1

2 major divisions of the nervous system

Answer 1

• Central Nervous System (CNS): Brain and spinal cord

- Peripheral Nervous System (PNS): everything outside brain and spinal cord

Question 2

2 divisions of the PNS

Answer 2

• Somatic nervous system (SNS)

- Autonomic Nervous system (ANS)

Question 3

Somatic nervous system

Answer 3

• interacts with external environment; controls voluntary muscles
• Has afferent nerves that carry sensory signals in from the skin, skeletal muscles, joints, eyes, ears, etc. into CNS (body -> brain)
• Has efferent nerves that carry motor signals from CNS out to skeletal muscles (brain -> body)

Question 4

Autonomic nervous system

Answer 4

• Regulates internal environment; controls internal organs
• Has afferent nerves that carry sensory signals from internal organs to the CNS
• Has efferent nerves that carry motor signals from the CNS to internal organs (2 types)

Question 5

2 types of efferent nerves in Autonomic Nervous System

Answer 5

• Sympathetic nerves:
• • Mobilize energy resources in threatening situations (ie. Via adrenal glands) to help you take action
• Parasympathetic nerves:
• • Conserve energy; facilitates immune function, digestion, etc.
• We usually receive input from these systems at the same time (not true that only one or the other is activated)

Question 6

Term for clusters of cell bodies in CNS vs. PNS

Answer 6

• In CNS: “Nucleus”

- In PNS: “Ganglia”

Question 7

Term for bundles of axons in CNS vs. PNS

Answer 7

• In CNS: “tract”

- In PNS: “nerve”

Question 8

Alternate term for “axons”

Answer 8

“Fibers”

Question 9

Basic neuroanatomical directional terms

Answer 9

• Anterior/rostral (front)
• Posterior/caudal (back)
• Dorsal/superior (top)
• Ventral/inferior (bottom)

Question 10

Directions in the NS/Brain

Answer 10

• Medial (vertical slice through middle)

- Lateral (either to the left or right of that vertical slice; left lateral or right lateral)

Question 11

Planes the brain is cut on

Answer 11

• Coronal (frontal) section (like a slice encompassing your whole face)
• Horizontal section (like a slice cutting horizontally through the top of your head)
• [Mid-]sagittal section (like a vertical slice between your eyes)

Question 12

spinal cord

Answer 12

• Different sections (from top to bottom): cervical, thoracic, lumbar, sacral, coccygeal)
• On spinal cord, most of sensory info comes from dorsal side; on ventral side is where motor information is exiting
• 2 different areas of each piece of spinal cord:
• • Inner H-shaped core of grey matter: composed largely of cell bodies and unmyelinated axons
• • Surrounding area of white matter: composed of unmyelinated axons

Question 13

Major divisions of the brain

Answer 13

• Forebrain (incl. telencephalon & diancephalon)
• Midbrain (incl. mesencephalon)
• Hindbrain (incl. metacephalon & myelencephalon)

Question 14

myelencephalon

Answer 14

• AKA: Medulla
• Composed largely of tracts carrying signals between the rest of the brain and the body
• Contains reticular formation (~100 nuclei involved in myriad functions)
• Important for basic life functions

Question 15

metencephalon

Answer 15

• Houses many fiber tracts & reticular formation
• Fibers and pontine nuclei create large bulge: “pons”
• Contains cerebellum (10% of brain volume but 50% of its neurons)

Question 16

mesencephalon

Answer 16

composed of tectum and tegmentum

Question 17

tectum

Answer 17

• composed of 2 pairs of bumps; inferior colliculi and superior colliculi (on dorsal side)
• • Inf: responds to auditory stimuli
• • Sup: responds to visual stimuli

Question 18

tegmentum

Answer 18

• contains:
• • Top of the reticular formation
• • Fibers of passage
• • Periaqueductal grey (resp. for old evolutionary behaviours - ie. Rats running away from threats)
• • Substantia nigra (provides dopamine to other areas of brain, important for movement)
• • Red nucleus (resp. For organism-specific behaviours - ie. eats squeaking vs. Dogs barking); on ventral side

Question 19

diancephalon

Answer 19

• Composed of thalamus and hypothalamus
• • Thalamus: comprises many different types of nuclei, including sensory relay nuclei. Includes Corticothalamic loop: allows us to be awake and aware
• • Hypothalamus: plays important role in several behaviours due partly to its effect on pituitary gland

Question 20

telencephalon

Answer 20

• Largest division of brain

- Cerebral cortex is its most prominent constituent; also contains corpus callosum

Question 21

location and function of corpus callosum

Answer 21

• Located in telencephalon

- Connects the cerebral hemispheres together (along with other cerebral commissures)

Question 22

appearance of cerebral cortex

Answer 22

• Highly convoluted (increases surface area while maintaining a small volume), unlike many smooth-brained mammals
• Large furrows are called fissures or sulci; ridges between fissures are called gyri
• • Largest fissure is the longitudinal fissure (goes through centre of the brain, separates left and right hemisphere)
• Interindividual cortical variability – lots of variation amongst individuals, but similarity between identical twins

Question 23

Limbic system components

Answer 23

• Fornix
• Left and right cingulate cortex
• Hippocampus
• Amygdala
• Mammillary body
• Septum

Question 24

Basal ganglia components

Answer 24

• Striatum (Caudate and putamen); made up of nucleus accumbens
• Thalamus
• Amygdala
• Globus pallidus

Question 25

Lobes of cerebral cortex

Answer 25

- Two major landmarks: Central fissure and lateral fissure | - Four lobes: Occipital, Temporal, Parietal, and Frontal.

Question 26

anatomical features that protect the brain

Answer 26

- skull - meninges - ventricles

Question 27

3 layers of meninges

Answer 27

- Dura matter - Arachnoid matter - Pia matter

Question 28

types of ventricles

Answer 28

- Lateral ventricles - Third ventricle - Cerebral aqueduct - Fourth ventricle (close to medulla and pons) - Central canal