Chapter 13: Nervous System: Brain & Cranial Nerves

What is a bundle of axons in the CNS called?

Tract

A bundle of axons within the peripheral nervous system

Nerves

Where is the ganglia located

PNS

What is the group of Neuron cell bodies in the peripheral nervous system called?

Ganglion

Cellular Structure housing DNA or a group of cell bodies in the central nervous system

Nucleus

The largest part of the brain that is responsible for higher cognitive functions

Cerebrum

What are the structures of the cerebrum

• Cerebral cortex

• Lt and Rt Hemispheres

The outer gray matter that is responsible for conscious though, sensory processing and voluntary movement is the…?

Cerebral Cortex

What are the two parts of the Cerebral Hemispheres

Left and Right

Name the lobes of the Cerebrum

• Frontal lobe

• Parietal Lobe

• Temporal Lobe

• Occipital Lobe

• Insula or Deep Lobe

This lobe controls:

• voluntary movement

• reasoning

• problem-solving

• Speech

  • Brocas area

Frontal Lobe

This Lobe processes sensory information such as:

• Touch

• Pressure

• Pain

Parietal Lobe

This lobe is responsible for hearing and memory

• Contains Wernickes area for language comprehension

Temporal lobe

This lobe processes visual information

Occipital lobe

This lobe is involved in taste and visceral sensation

Deep lobe - AKA Insula

This part of the brain Regulates movement coordination

Basal Nuclei (Basal Ganglia)

What is the function of the Corpus Callosum?

It connects the two hemispheres and enables communication

This part of the brain is located deep within the brain, and regulates homeostasis and sensory processing

Diencephalon

What are the Structures located in the diencephalon?

• Thalamus

• Hypothalamus

• Epithalamus (Pineal Gland)

• Subthalamus

What is the function of the Thalamus?

The relay center for sensory information with the exception of smell

This structure is located in the Diencephalon and regulates hormones, hunger, thirst, temperature, and the autonomic nervous system.

Hypothalamus

What does the Epithalamus (Pineal Gland) Produce?

Melatonin in order to regulate sleep?

This structure is located in the diencephalon and is involved in Motor control.

Sub-thalamus

This part of the brain controls basic life functions like

• Breathing

• Heart rate

• Reflexes

Brain stem

What are the structures located in the Brainstem?

• Midbrain/Mesencephalon

• Pons

• Medulla Oblongata

This part of the brainstem contains visual and auditory reflex centers

• Superior and Inferior colliculi

Midbrain/Mesencephalon

This part of the brainstem bridges the cerebrum and cerebellum and is involved in breathing control

Pons

What is the function of the Medulla Oblongata?

Its Regulates vital autonomic functions like:

• heart rate

• respiration

• digestion

Where is the Cerebellum located and what is its function?

Location - Back of the brain

Function - Coordinates movement and balance

What are the structures located in the Cerebellum

• Cerebellar Hemispheres

• Vermis

• Arbor Vitae

The left and right portions of _______ ______ help with motor coordination

Cerebellar Hemisphere

What is the purpose of the vermis?

It connects the two hemispheres

This structure is a white matter structure that looks tree-like and allows communication within the cerebellum

Arbor Vitae

Gray matter is mostly composed of…?

• Neuron Cell bodies

• Dendrites

• Unmyelinated axons

What is the function of Gray matter?

• Processing

• Integration

• Decision-making

• Synaptic transmission

This matter appears darker due to neuron cell bodies

Gray matter

What is White matter composed of?

• Myelinated axons

What is the function of white matter?

Transmits signals rapidly between different regions of the CNS

This matter appears lighter due to the fatty myelin sheath

White matter

Where in the spinal cord is gray matter located?

Found inside the H-shaped (butterfly) structure

What is the function of the dorsal horn of the spinal cord?

It receives sensory input from body, such as pain, temperature, and touch

What is the function of the ventral horn of the spinal cord?

It sends motor output to muscles for voluntary movement.

Where is the lateral horn found, and what does it control?

Found in the thoracic and upper lumbar regions; controls autonomic (involuntary) functions like heart rate and digestion.

Where is white matter located in the spinal cord?

It surrounds the gray matter and contains nerve tracts for communication.

What is the main function of white matter in the spinal cord?

It transmits signals through ascending sensory tracts and descending motor tracts.

What type of information is carried in the dorsal (posterior) column of white matter?

Sensory information (touch, vibration, proprioception) to the brain.

What type of information is carried in the lateral column of white matter?

Both sensory (pain, temperature) and motor (voluntary movement) signals.

What type of information is carried in the ventral (anterior) column of white matter?

Motor commands from the brain to the muscles.

What is the difference between gray matter and white matter in the spinal cord?

• Gray Matter: Processes and integrates information.

• White Matter: Transmits information between the brain and body.

Where is Gray matter located in the brainstem

It is Scattered in the nuclei

Where is white matter located in the brainstem?

it is mostly found in in tracts connecting in the spinal cord and higher brain structures

What structures are considered higher brain?

Cerebrum & Cerebellum

Where is gray matter found in the higher brain

It is found in the cerebral cortex (the outer layer) and the deep nuclei (basal nuclei, thalamus)

White matter is found where in the higher brain

It is found in the inner tracts

• Corpus Callosum ~ connects the two hemispheres

• Internal capsule ~ connects cortex to spinal cord

Where are the lateral ventricles located (1st and 2nd ventricles)

• One in each cerebral hemisphere

• are located deep within the cerebral hemispheres under the corpus callosum

• they are connected the third ventricle through the inter-ventricular for

Where is the third ventricle located?

• In the diencephalon

• Between the two halves of the thalamus in the diencephalon

• is connected to the fourth ventricle through the cerebral aqueduct

Where is the fourth ventricle located

• between the pons and medulla oblongata (anterior) and the cerebellum(posterior)

• is connected to the central canal of the spinal cord and the subarachnoid space through the median aperture and lateral apertures

How is the cerebral cortex functionally divided?

The cerebral cortex is divided into three functional areas: sensory areas, motor areas, and association areas.

What is the function of sensory areas in the cerebral cortex?

They receive and process sensory information, such as touch, vision, hearing, taste, and smell.

What is the function of motor areas in the cerebral cortex?

They control voluntary movements by sending signals to muscles.

What is the function of association areas in the cerebral cortex?

They integrate and process sensory and motor information, allowing for higher cognitive functions like reasoning, memory, and decision-making.

Where is the primary motor cortex located, and what is its function?

Located in the precentral gyrus of the frontal lobe, it controls voluntary movements of skeletal muscles.

What is the function of the premotor cortex?

It plans and coordinates complex movements.

Where is Broca’s area located, and what does it control?

Located in the left frontal lobe, it controls the muscles involved in speech production

What is the function of the frontal eye field?

It controls voluntary eye movements.

What is the function of the primary somatosensory cortex, and where is it located?

Located in the postcentral gyrus of the parietal lobe, it receives and interprets touch, pressure, pain, temperature, and proprioception.

How does the somatosensory association cortex support sensation?

It integrates and interprets sensory information to provide a better understanding of objects being touched.

Where is the primary visual cortex located, and what is its function?

Located in the occipital lobe, it processes visual information from the retina.

What does the visual association area do?

It helps recognize and interpret visual stimuli, such as faces and objects.

What does the primary auditory cortex process?

Sound properties such as pitch, loudness, and location

What is the function of the auditory association area?

it interprets and gives meaning to sounds, including speech, and music

What does the olfactory cortex process

It processes the sense of smell

What does the gustatory cortex process, and where is it located?

Is located in the insula, it processes taste perception

What does the vestibular cortex control?

It processes balance and spatial orientation Wh

What are the main functions of the prefrontal cortex?

Controls decision making, personality, problem solving, and social behavior.

Where is Wernickes area locate, and what is its function?

Located in the left temporal lobe

Is responsible for understanding language ~ both spoken and written

What is the posterior association area responsible for?

It integrates sensory input for perception and spatial awareness

What is the function of the limbic association area?

It is involved in controlling emotions, memory, and motivation

What is the function of the Reticular Activating System (RAS)

It regulates wakefulness, alertness, and consciousness

Where is RAS located

it is found within the reticular formation, extending through the brainstem

• Medulla

• Pons

• Midbrain

What are the main functions of the RAS

• Maintains consciousness and alertness

• Filters irrelevant stimuli to prevent sensory overload

• Regulates sleep-wake cycles

• Plays a role in arousal and attention

What are the key structures involved in the RAS?

• Reticular formation

• Thalamus

• Cerebral cortex connections

What can happen if the RAS is damaged?

It can result in a coma or loss of consciousness

How does RAS overactivation affect a person?

It can contribute to insomnia or anxiety disorder

______ are three protective layers that surround the brain and spinal cord which provide cushioning, protection, and support

Meningeal Coverings of the CNS

What are the three meninges covering the brain and spinal cord

1. Dura mater

2. Arachnoid mater

3. Pia mater

What is the outermost meningeal layer, and what is its function?

Tough, fibrous outer later that provides structural support and forms venous sinuses

What are the two layers of the dura mater in the brain

1. Periosteal layer

2. Meningeal layer

The periosteal layer is attached to the _____

Skull

The Meningeal layer is closer to the _____

Brain

What is the middle meningeal layer, and what is its function?

Arachnoid mater - It is a web like layer that aids to absorb cerebrospinal fluid into venous circulation.

What structure allows CSP to be reabsorbed into the bloodstream>?

Arachnoid villi (granulations)

What is the innermost meningeal layer, and what is its function?

Pia mater - It is a thin, vascular layer that adheres to the brain and supplies nutrients

What space lies between the dura mater and arachnoid mater?

Subdural space - A potential space that can fill with blood and case of injury

What space lies between the arachnoid and pia mater, and why is it important?

Subarachnoid space - Contains cerebrospinal fluid and blood vessels that nourish the CNS

Where does CSP circulate in the meninges

Subarachnoid Space

What is the function of the arachnoid trabeculae?

Thin fibers that connects the arachnoid mater to the pia mater and help susbens the brain within the CSF

What is the subdural hematoma?

A bleeding condition where blood collects the subdural space due to trauma.

What us meningitis and which later does it most commonly affect?

Meningitis is an infection and inflammation of the meninges, usually affecting the pia mater and arachnoid mater