Neuroscience: Brain Structures, Functions, and Divisions

What are the two main divisions of the nervous system?

Central nervous system (CNS) and peripheral nervous system (PNS)

What structures comprise the central nervous system?

The brain and spinal cord

What is the function of the motor (efferent) division of the nervous system?

Conducts impulses from the CNS to effectors (muscles and glands)

What is the role of the sensory (afferent) division of the nervous system?

Conducts impulses from receptors to the CNS

What are the two subdivisions of the motor division?

Somatic nervous system (voluntary) and autonomic nervous system (involuntary)

What does the autonomic nervous system (ANS) control?

Cardiac muscles, smooth muscles, and glands

What are the two divisions of the autonomic nervous system?

Sympathetic division (mobilizes body systems during activity) and parasympathetic division (conserves energy and promotes housekeeping functions during rest)

What are the primary brain vesicles formed from the neural tube?

Forebrain, midbrain, and hindbrain

What structures develop from the forebrain?

Cerebral hemispheres (cerebrum) and diencephalon (thalamus and hypothalamus)

What is the function of the cerebral hemispheres?

Initiate voluntary movement and process sensory information

What are gyri and sulci in the brain?

Gyri are elevated ridges of tissue; sulci are shallow grooves that separate gyri

What is the role of the corpus callosum?

Connects corresponding areas of the left and right cerebral hemispheres

What is the significance of the longitudinal fissure?

It separates the left and right cerebral hemispheres

What is the function of the postcentral gyrus?

Receives sensory input for conscious touch and proprioception

What is the function of the precentral gyrus?

Initiates voluntary movement

What are the four major lobes of the cerebral hemispheres?

Frontal lobe, parietal lobe, temporal lobe, and occipital lobe

What does the thalamus do?

Acts as a relay station for sensory impulses to the cerebral cortex

What is the function of the hypothalamus?

Regulates autonomic functions, hormone release, and homeostasis

What is the role of the cerebellum?

Coordinates voluntary movements and maintains posture and balance

What is the medulla oblongata responsible for?

Regulating vital functions such as heart rate and breathing

What is the function of the pons?

Connects different parts of the brain and regulates sleep and arousal

What is the significance of the cerebral cortex?

It is the outer layer of the brain responsible for higher brain functions

How much does the average adult human brain weigh?

About 3 pounds

What is a fun fact about Albert Einstein's brain?

It weighed only 2.7 pounds and had a thinner cerebral cortex

What are projection fibers in the brain?

Connect the cerebral hemispheres to lower areas of the CNS

What is the third ventricle?

A cavity in the brain that contains cerebrospinal fluid

What is the role of the postcentral gyrus?

It is responsible for conscious touch and proprioception.

Where is the primary motor cortex located?

In the precentral gyrus.

What is the central sulcus?

A prominent groove that separates the frontal lobe from the parietal lobe.

What is the primary somatosensory cortex responsible for?

Receiving sensory information from the skin and skeletal muscles.

What are the three basic regions of each cerebral hemisphere?

Cerebral cortex (gray matter), cerebral white matter, and basal nuclei.

What is the appearance of gray matter?

It appears gray due to unmyelinated parts of neurons.

What is the appearance of white matter?

It appears white because it consists mostly of myelinated axons.

What is the function of association fibers?

They connect different parts of the same hemisphere.

What is the role of commissural fibers?

They connect the two cerebral hemispheres.

What is the function of projection fibers?

They connect the cerebral cortex to lower brain areas.

What is the anterior association area also known as?

The prefrontal cortex.

What cognitive functions is the prefrontal cortex involved in?

Intellect, cognition, recall, personality, judgment, and reasoning.

What is the primary visual cortex responsible for?

Processing visual information.

What is the primary auditory cortex responsible for?

Processing auditory information.

What is the function of Broca's area?

Involved in language production.

What is the function of Wernicke's area?

Involved in language comprehension.

What does the term 'multimodal association areas' refer to?

Regions that receive input from multiple senses and send outputs to multiple areas.

What is the role of the premotor cortex?

Involved in planning and executing learned motor skills.

What type of sensory information does the primary somatosensory cortex receive?

Information from skin for touch and from muscles for proprioception.

What is the function of the gustatory cortex?

Processing taste information.

What is the primary function of the central sulcus?

Separates the primary motor cortex from the primary somatosensory cortex.

What is the role of the somatosensory association cortex?

Integrates sensory input and helps in spatial discrimination.

What is the primary function of the frontal eye field?

Controls voluntary eye movements.

What is the function of the auditory association area?

Processes and interprets sounds.

What is the primary function of the primary somatosensory cortex?

It receives and processes sensory input from the body, allowing for the perception of touch and proprioception.

What does the somatosensory association cortex do?

It integrates sensory input from the primary somatosensory cortex to determine size, texture, and the relationship of parts of objects being felt.

What is the role of the primary visual cortex?

It receives visual information from the retinas and is located in the occipital lobe.

What is the function of the visual association area?

It interprets visual stimuli using past visual experiences, such as color and movement.

What does the auditory association area do?

It stores memories of sounds and helps in the perception of auditory information.

What is somatotopy?

It is the spatial mapping of the body in the primary motor cortex and primary somatosensory cortex.

What is the homunculus?

A distorted representation of the human body used to illustrate the somatotopic organization of the primary motor and somatosensory cortices.

Which lobe contains the primary auditory cortex?

The temporal lobe.

What type of neurons are found in the cerebral cortex?

All neurons in the cortex are interneurons (association neurons).

What are the three types of functional areas of the cerebral cortex?

Motor areas, sensory areas, and association areas.

What is the location of the primary visual cortex?

In the extreme posterior tips of the occipital lobe.

What sensory input does the primary somatosensory cortex not receive?

It does not receive input for vision, hearing, smell, or taste.

Where does the primary auditory cortex receive input from?

It receives input from the inner ear.

What is the function of the premotor cortex?

It is involved in planning and coordinating movements.

What part of the brain is affected if a man is partially paralyzed in his left arm and leg?

The precentral gyrus in the left hemisphere.

What is the significance of the central sulcus?

It separates the primary motor cortex from the primary somatosensory cortex.

What does the gustatory cortex process?

Taste sensations.

What is the role of Wernicke's area?

It is involved in language comprehension.

What is the primary olfactory cortex responsible for?

It processes smell information.

What is the primary function of the motor association cortex?

It is involved in planning and executing voluntary movements.

What does the term 'multimodal association cortex' refer to?

Areas of the cortex that integrate information from multiple sensory modalities.

What is the significance of the postcentral gyrus?

It is the location of the primary somatosensory cortex.

What type of sensations does the somatosensory association cortex integrate?

It integrates tactile sensations to identify objects by touch.

What does the term 'sensory areas' refer to in the context of the cerebral cortex?

Regions of the cortex that process sensory information from various modalities.

What are the three types of functional areas of the cortex?

Sensory, motor, and association areas.

What type of neurons are all neurons in the cortex?

Interneurons (association neurons).

What is the function of the primary somatosensory cortex?

It perceives conscious touch and proprioception.

Where is the primary somatosensory cortex located?

In the postcentral gyrus.

What is the appearance of cerebral white matter due to?

Numerous myelinated axons.

What are the three types of fibers in cerebral white matter?

Commissural fibers, association fibers, and projection fibers.

What do commissural fibers do?

Run horizontally between hemispheres.

What do association fibers do?

Run horizontally within the same hemisphere.

What do projection fibers do?

Run vertically between the cerebral cortex and lower areas of the brain or spinal cord.

What is the name of the 'bridge' between both cerebral hemispheres?

The corpus callosum.

What is the role of motor tracts?

They descend to carry motor output from the primary motor cortex.

What is the role of sensory tracts?

They ascend to carry sensory input to the primary somatosensory cortex.

What is the function of the spinal cord?

It provides two-way communication between the brain and the periphery.

What types of spinal nerves are there?

Cervical, thoracic, lumbar, and sacral spinal nerves.

What is the correct sequence of communication in the nervous system for motor signals?

Motor signals descend from the brain to the spinal cord to muscles.

What is the correct sequence of communication in the nervous system for sensory signals?

Sensory signals ascend from sensory receptors to the spinal cord to the brain.

What type of neuron are 1st order neurons in the dorsal column-medial lemniscal pathway?

Unipolar sensory neurons.

What happens to 2nd order neurons in the dorsal column-medial lemniscal pathway?

They decussate (cross over to the opposite side) and ascend to the thalamus.

What is the function of 3rd order neurons in the sensory pathway?

They project from the thalamus to the primary somatosensory cortex.

Where do sensory inputs from the left side of the body arrive in the brain?

In the primary somatosensory cortex of the right hemisphere.

What is the primary pathway for conscious touch and proprioception?

The dorsal column-medial lemniscal pathway.

What is the role of the thalamus in sensory processing?

It acts as the gateway to the cortex.

What is the significance of the precentral gyrus?

It houses the primary motor cortex.

What is the role of the spinal cord in reflex actions?

It carries out spinal reflexes between the periphery and the spinal cord.

Where do pyramidal (corticospinal) tracts originate?

In the primary motor cortex located in the precentral gyrus.

What is the role of upper motor neurons in the pyramidal pathways?

They descend from the motor cortex to the spinal cord and synapse with lower motor neurons.