Structure of the Vertebrate Nervous System

Flashcards testing terminology, anatomical planes, structural divisions, functional localization, subcortical regions, and cortical organization from Module 3.1 Structure of the Vertebrate Nervous System.

What anatomical terms describe directions toward the top and bottom of the brain?

Dorsal refers to toward the top of the brain, while ventral refers to toward the bottom of the brain.

What is the difference between medial and lateral directions in brain anatomy?

Medial means toward the middle or midline, whereas lateral means toward the edge or away from the midline.

What do the terms ipsilateral and contralateral mean?

Ipsilateral means located on the same side of the body, whereas contralateral means located on the opposite side.

What directional terms refer to the front and back of the brain?

Anterior refers to toward the front of the brain, and posterior refers to toward the back of the brain.

How are superior and inferior defined in anatomical directional terms?

Superior means above another part, and inferior means below another part.

What is a tract, projection, or fasciculus?

A set of axons in the Central Nervous System (CNS) that travel together (for example, the corpus callosum).

What is a nerve in the nervous system?

A set of axons located outside the Central Nervous System (CNS) (for example, the optic nerve).

What is a nucleus in neuroanatomy?

A cluster of neuron cell bodies located within the Central Nervous System (CNS) (for example, the nucleus accumbens).

What is a ganglion?

A cluster of neuron cell bodies located outside the Central Nervous System (CNS) (for example, the dorsal root ganglion).

What are the two major divisions of the nervous system?

The Central Nervous System (CNS), consisting of the brain and spinal cord, and the Peripheral Nervous System (PNS), which connects the brain and spinal cord to the rest of the body.

What are the roles of the somatic and autonomic nervous systems within the PNS?

The somatic nervous system conveys sensory information to the CNS and controls voluntary muscles. The autonomic nervous system controls involuntary muscles and internal organs like the heart and intestines.

How do the sympathetic and parasympathetic nervous systems differ in function and ganglion layout?

The sympathetic nervous system expends energy to prepare organs for fight-or-flight activities and has ganglia arranged in closely linked chains. The parasympathetic nervous system conserves energy during rest-and-digest responses and has unlinked ganglia.

What specific bodily responses are triggered by activation of the sympathetic nervous system?

Pupils dilate, heart rate and contraction force increase, sweat secretion increases, blood vessels constrict (increasing blood pressure), digestion slows down, and saliva secretion is reduced.

What bodily responses are triggered by activation of the parasympathetic nervous system?

Pupils constrict, heart rate and contraction force decrease, blood vessels dilate (decreasing blood pressure), digestion increases, and saliva secretion increases.

How many pairs of spinal nerves are in the segmented spinal cord?

The spinal cord is segmented into 31 pairs of spinal nerves.

What is the Bell-Magendie Law?

A principle stating that dorsal roots carry incoming sensory information (with cell bodies in dorsal root ganglia) and ventral roots carry outgoing motor information (with cell bodies inside the spinal cord).

How are gray and white matter arranged in the spinal cord versus the brain?

In the spinal cord, gray matter (cell bodies/dendrites) is at the center and white matter (myelinated axons) is on the outside. In the brain, gray matter is mainly on the outside and white matter is inside.

What major structures belong to the hindbrain, midbrain, and forebrain?

Hindbrain: Medulla, pons, cerebellum. Midbrain: Tectum, tegmentum, substantia nigra. Forebrain: Thalamus, hypothalamus, hippocampus, basal ganglia, cerebral cortex.

What structures compose the brainstem and what are its general functions?

Composed of the medulla, pons, midbrain, and parts of the forebrain. It handles sensory/motor connections between brain and body, cranial nerves, sleep cycles, consciousness, and cardiac/respiratory functions.

What structure is highlighted by the blue circle in this brainstem diagram?

The medulla, located just above the spinal cord, which controls vital reflexes such as breathing, heart rate, vomiting, salivation, coughing, and sneezing.

What structure is circled in blue in this diagram, and what is its main function?

The pons. It contains axons crossing to the opposite side of the spinal cord (contralateral control), relays sensory info from forebrain to cerebellum, and participates in sleep, respiration, swallowing, and facial functions.

What are the functions of the Reticular Formation and the Raphe system in the medulla and pons?

The Reticular Formation increases arousal/attention, controls conscious sensory input, and mediates habituation. The Raphe system releases serotonin, regulates circadian rhythms/sleep cycles, and modifies responsiveness to stimuli.

What hindbrain structure is circled in blue in this image, and what functions does it serve?

The cerebellum. It controls movement (balance, coordination, fine adjustments), motor learning, classical conditioning, and cognitive functions such as reading, shifting attention, and rhythm judgments.

What are the components of the tectum in the midbrain and their functions?

The superior colliculus (involved in preliminary vision processing and eye movements) and the inferior colliculus (involved in auditory spatial localization and the startle response).

What is the function of the substantia nigra, and what condition results from cell death here?

It contains a dopamine pathway that facilitates movement. Death of cells in the substantia nigra leads to Parkinson's Disease, causing difficulty starting movements and slowness in execution.

Which subcortical forebrain region is circled in blue in this sagittal section?

The thalamus, which serves as a relay station receiving and processing sensory information (except olfaction) before sending output to the cortex.

What are the two specialized sensory nuclei in the thalamus mentioned in the lecture?

The lateral geniculate nucleus (for visual input) and the medial geniculate nucleus (for auditory input).

What brain structure is highlighted by the blue circle in this diagram?

The hypothalamus, located ventral to the thalamus, which regulates motivated behaviors (feeding, fleeing, fighting, sexual behavior, temperature regulation, drinking) and signals the pituitary gland.

Which neuroendocrine gland is circled in blue in this figure?

The pituitary gland, consisting of a posterior pituitary (brain tissue releasing vasopressin and oxytocin) and an anterior pituitary (glandular tissue synthesizing hormones under hypothalamic control).

What structures compose the basal ganglia, and what disorder is associated with damage to them?

Composed of the caudate nucleus, putamen, and globus pallidus. Damage impairs movement and learning skills, resulting in conditions like Huntington's disease (inability to control unwanted movements).

What are the primary functions of the amygdala?

Emotional processing, particularly learning what to be afraid of, and being active when observing emotion in others.

What are the main functions of the hippocampus, and what did patient H.M.'s surgery reveal about it?

Consolidates short-term memories into long-term memories and handles spatial navigation. Patient H.M. lost bilateral hippocampi, resulting in an inability to form new long-term declarative memories while retaining working memory and motor learning.

How is cerebrospinal fluid (CSF) created, and what functions does it serve?

Choroid plexus cells produce CSF inside the four brain ventricles. It cushions the brain, supports its weight, and delivers hormones and nutrients to the brain and spinal cord.

What condition is caused by a blockage of cerebrospinal fluid (CSF) flow?

Hydrocephalus, where accumulated fluid pressure can damage brain tissue.

Which meningeal layer is the middle layer shown in this diagram?

The arachnoid mater, positioned between the outer dura mater and the inner pia mater.

What structures connect the left and right hemispheres of the cerebral cortex?

The corpus callosum and the anterior commissure.

What is the structural difference between a gyrus and a sulcus?

A gyrus is a bump or ridge on the surface of the brain, whereas a sulcus is a fold or groove between gyri.

How are cells structurally organized in the cerebral cortex?

In up to six distinct laminae (layers) parallel to the cortical surface, as well as functional columns arranged perpendicular to the laminae.

What is cortical blindness and what structural damage causes it?

It is a loss of conscious visual perception, visual imagery, and vision in dreams caused by damage to the primary visual cortex (V1 / striate cortex) in the occipital lobe.

Where is the postcentral gyrus located and what is its primary function?

Located in the parietal lobe; it contains the primary somatosensory cortex (S1) which receives input from touch, muscle-stretch, and joint receptors.

What additional cognitive/sensory functions are mediated by the parietal lobe?

Multimodal integration (audio/visual, guided action), spatial information (location in space), and numerical information (calculations/magnitude).

What functional roles are associated with the temporal lobe?

Auditory processing (left hemisphere language comprehension), complex vision (movement, face recognition), and emotional/motivational behaviors.

What is Klüver-Bucy syndrome?

A behavioral syndrome resulting from temporal lobe damage (observed in wild monkeys) where subjects fail to display normal fear and anxiety.

What structure is contained within the precentral gyrus of the frontal lobe?

The primary motor cortex, which controls fine motor movements, primarily on the contralateral side of the body.

What key functions are managed by the prefrontal cortex?

Language production (Broca's area), working memory (remembering recent events), decision-making, planning movements, and emotional/attention regulation.