STRUCTURE OF THE VERTEBRATE NERVOUS SYSTEM & CEREBRAL CORTEX

Nervous System

The overall network of cells and tissues responsible for controlling and coordinating all bodily functions.

Central Nervous System

The main control center of the nervous system, consisting of the brain and spinal cord.

Brain

The most complex organ in the human body, responsible for higher-order functions like thought, emotion, memory, and movement.

Spinal Cord

A long, bundled structure that extends from the base of the brain to the lower back. It acts as a communication highway between the brain and the rest of the body.

Peripheral Nervous System

The network of nerves that connect the CNS to the rest of the body. It consists of two main divisions

1. Somatic Nervous System

2. Autonomic Nervous

Peripheral Nervous System consists of two main divisions

Somatic Nervous System

Controls voluntary movements, such as walking, talking, and writing. It is responsible for sending and receiving sensory information from the body to the brain.

autonomic nervous system

Controls involuntary functions, such as heart rate, blood pressure, digestion, and body temperature. It is further divided into two branches

1. Sympathetic Nervous System

2. Parasympathetic Nervous System

Autonomic is divided into two branches

sympathetic nervous system

Prepares the body for a fight-or-flight response, increasing heart rate, blood pressure, and breathing rate.

Parasympathetic nervous system

Calms the body down after a stressful situation, returning it to a normal state. “Rest and digest”

sagittal plane

A vertical plane that divides the body into left and right halves.

coronal plane

A vertical plane that divides the body into anterior (front) and posterior (back) halves.

horizontal plane

— that divides the body into superior (top) and inferior (bottom) halves.

anterior

Toward the front of the body

posterior

Toward the back of the body.

superior

Toward the top of the body

inferior

Toward the bottom of the body

lateral

Toward the side of the body.

medial

Toward the middle of the body.

dorsal

Toward the back or upper surface of the body, especially in animals.

ventral

Toward the front or lower surface of the body, especially in animals.

lamina

A layer or sheet of cell bodies within the nervous system. It's separated from other cell bodies by layers of axons and dendrites.

column

a set of cells perpendicular to the surface of the cortex, with similar properties

tract

A set of axons within the CNS, also known as a projection, if axons extend from the cell bodies in structure A to synapses onto B, we say that the fibers “project from A onto B

Nerve

a set of axons in the periphery, either from CNS to a muscle or gland or from a sensory organ to the CNS

Nucleus

A cluster of neuron cell bodies within the CNS

Ganglion

a cluster of neuron cell bodies, usually outside the CNS (as in the sympathetic nervous system

Gyrus

a protuberance on the surface of the brain

sulcus

a fold or groove that separates one gyrus from another

fissure

a long, deep sulcus

dorsal root ganglion

This is a cluster of nerve cell bodies located outside the spinal cord. It houses the sensory neurons that transmit sensory information from the body to the spinal cord.

gray matter

This region is primarily composed of neuron cell bodies, dendrites, and synapses. It is responsible for processing information and integrating sensory input with motor output.

central canal

This is a small channel filled with cerebrospinal fluid (CSF), which provides nourishment and protection to the spinal cord.

white matter

This region is primarily composed of myelinated axons, which transmit information up and down the spinal cord.

ventral root

This is the exit point for motor neurons that carry commands from the brain to the muscles.

1. forebrain

2. midbrain

3. hindbrain

major divisions of the human brain

forebrain

• This is the largest part of the brain and is responsible for a wide range of functions, including:

• Processing sensory information

• Reasoning and problem-solving — is involved in higher-order cognitive functions such as thinking, planning, and decision-making.

• The forebrain helps to control involuntary bodily functions such as heart rate, blood pressure, and digestion.

• Endocrine and motor functions

midbrain

• This smaller region of the brain is located between the forebrain and hindbrain. Its functions include:

• Regulating movement: The— helps to coordinate movements and maintain balance.

• Processing auditory and visual information: The— receives and processes information from the ears and eyes.

hindbrain

• This is the lowermost part of the brain and is responsible for basic life-sustaining functions. Its functions include:

• Regulating autonomic functions: The — helps to control involuntary bodily functions.

• Relaying sensory information: The— relays sensory information from the body to the brain.

• Coordinating movement: The— helps to coordinate movements and maintain balance.

1. medulla oblongata

2. pons

3. cerebellum

hindbrain is divided into 3 main parts

medulla oblongata

This is the lowermost part of the brainstem and is responsible for regulating vital functions such as breathing, heart rate, and blood pressure. It also contains the decussation of pyramids, where most motor fibers cross over to the opposite side of the body.

pons

Located above the medulla oblongata, the — is involved in regulating breathing, sleep, and relaying sensory information to the brain. It also contains nuclei for several cranial nerves.

cerebellum

The — is located behind the brainstem and is primarily responsible for coordinating movement, maintaining balance, and regulating muscle tone. It also plays a role in learning and memory.

1. tectum

2. tegmentum

midbrain is divided into two main parts

tectum

A region of the midbrain that includes the superior and inferior colliculi.

superior colliculi

Structures involved in visual processing and orienting the eyes toward visual stimuli.

inferior colliculi

Structures involved in auditory processing and orienting the head toward auditory stimuli.

tegmentum

A region of the midbrain that contains several important nuclei, including the substantia nigra (involved in motor control) and the periaqueductal gray (involved in pain modulation).

1. cerebral cortex

2. basal ganglia

3. hippocampus

4. thalamus

5. hypothalamus

parts of the forebrain

limbic system

a group of structures located within the forebrain that plays a crucial role in emotion, memory, and motivation.

olfactory bulb, hypothalamus, hippocampus, amygdala, and cingulate gyrus

parts of the limbic system

olfactory bulb

Processes information related to smell.

cingulate gyrus

Involved in emotion, attention, and memory.

amygdala

as it is a key structure in the limbic system for processing emotional information. It plays a crucial role in recognizing and responding to threats and in forming emotional memories.

cerebral cortex

is the outermost layer of the brain and is responsible for higher-order cognitive functions such as thought, perception, language, and voluntary movement.

frontal, parietal, temporal, occipital

cerebral cortex is divided into 4 lobes

basal ganglia

These structures are located deep within the cerebral cortex and play a role in motor control, learning, and reward. They are involved in diseases such as Parkinson's disease and Huntington's disease.

hippocampus

This structure is located within the temporal lobe and is involved in memory formation and retrieval.

thalamus

is a relay center for sensory and motor information. It also plays a role in regulating sleep and wakefulness.

hypothalamus

is a small region of the brain that regulates various bodily functions, including hunger, thirst, body temperature, and sleep. It also plays a role in the endocrine system by controlling the release of hormones from the pituitary gland.

1. caudate nucleus

2. putamen

3. globus pallidus

three major structures of the basal ganglia are:

nucleus basalis

receives input from the hypothalamus and basal ganglia and sends axons that release acetylcholine to widespread areas in the cerebral cortex

“seahorse”

Hippocampus came from the Latin word—

ventricles

are four fluid-filled cavities within the brain that are interconnected and contain cerebrospinal fluid

cerebrospinal fluid

is a clear fluid similar to blood plasma that has several important functions, including:

• Cushioning: — protects the brain and spinal cord from injury by acting as a shock absorber.

• Nourishment: — provides nutrients to the brain and spinal cord.

• Waste removal: — removes waste products from the brain and spinal cord.

laminae

- layer of cell bodies that are parallel to the surface of the cortex and separated from each other by layers of fibers

lamina V

• sends long axons to the spinal cord and other areas

• is the thickest in the motor cortex (greatest control of the muscle)

Lamina IV

• receives axons from the sensory nuclei of the thalamus

• prominent in the sensory areas of the cortex (visual, auditory, somatosensory)

occipital lobe

• is a region of the cerebral cortex located at the posterior (caudal) end of the cortex. This means it is situated towards the back of the brain.

• — plays a crucial role in visual processing. It is the primary target for visual information, meaning it receives and interprets the signals from the eyes.

primary visual cortex or striate cortex.

• The posterior pole of the occipital lobe is a specific area known as the —-

• This region is responsible for the initial processing of visual information, such as detecting edges, colors, and simple shapes. It is essential for basic visual perception.

cortical blindness

occurs when there is damage to the visual cortex, specifically the primary visual cortex or striate cortex, located in the occipital lobe. This damage can result in the inability to see, even though the eyes and optic nerve are functioning normally.

parietal lobe

• a region of the cerebral cortex located between the occipital lobe and the central sulcus.

• is primarily involved in processing sensory information, especially related to touch, temperature, and pain. It also plays a role in spatial awareness, attention, and language.

central sulcus

is a deep groove in the surface of the cortex that separates the frontal lobe from the parietal lobe.

primary somatosensory cortex (postcentral gyrus)

located in the parietal lobe, is responsible for processing sensory information from the body. It creates a "map" of the body, with different areas representing different body parts. receives sensations from touch, musclestretch, and joint receptors.

temporal lobe

a region of the cerebral cortex located on the lateral side of each hemisphere, near the temples. The — plays a crucial role in auditory processing, language comprehension, and emotional and motivational behaviors.

left temporal lobe

is particularly important for understanding spoken language. Damage to this area can lead to language comprehension difficulties.

Klüver-Bucy Syndrome

• Damage to the temporal lobe can lead to a set of behaviors known as the —

• is a rare behavioral impairment that causes people to put objects in their mouths and engage in inappropriate sexual behavior. Other symptoms may include: Visual agnosia (inability to visually recognize objects) Loss of normal fear, anger responses, and memory loss

frontal lobe

• a region of the cerebral cortex located at the front of the brain. The — is the largest lobe of the brain and is responsible for a wide range of functions

• planning and initiating movements, decision-making, working memory, personality

primary motor cortex and the prefrontal cortex

fromtal lobe contains the —and—

primary motor cortex

This region is located in the precentral gyrus, a ridge on the frontal lobe. It is responsible for initiating voluntary movements. The — has a "motor homunculus," a distorted representation of the body where areas with greater motor control, like the hands and mouth, are larger.

prefrontal cortex

This is the largest part of the frontal lobe and is responsible for complex cognitive functions such as planning, decision-making, personality, and social behavior

precentral gyrus

a critical role in executing precise and detailed movements, such as writing, playing musical instruments, or performing delicate tasks. Damage to this region can lead to difficulties in controlling movements.