Topic 11 - Brain

3 primary vesicles

When it comes to the vesicles they start as

prosencephalon, mesencephalon, and rhombencephalon

Three primary vesicles

Five secondary brain vesicles

After an embryo is 5 weeks old the vesicles become

the telencephalon (cerebrum) and diencephalon (thalamus and hypothalamus)

Prosencephalon becomes

metencephalon (pons and cerebellum)and myelencephalon (medulla oblongata)

Rhombencephalon becomes the

midbrain, pons, and medulla

What is known as the brain stem

Cerebrum

most of the brain mass, divided into lobes, separated into hemispheres, and houses the lateral ventricles, covered by the cerebral cortex (higher function)

Cerebellum

second largest region, important for motor control

Diencephalon

houses everything ending in thalamus

Brain Stem

oldest region of the brain, most responsible for homeostatic function

Lobe

section of brain named for corresponding bone

Gyrus

ridge of a wrinkle

Sulcus

groove between gyri, lobes are separated by major sulci

Fissure

a very large sulcus

Rostral

closer to the forehead

Caudal

closer to the cauda equina

Cortex

external thin layer of gray matter

Nucleus

collection of gray matter deeper inside the white matter

Central Sulcus

separates frontal and parietal lobes

Lateral Sulcus

separates temporal lobe from frontal and parietal lobes

Longitudinal Fissure

separates right and left hemispheres

Precentral Gyrus

just anterior to central sulcus, primary motor area

Postcentral Gyrus

just posterior to central sulcus, primary sensory area

Occipital lobe

primary visual perception, vision is processed in temporal and parietal as well

Temporal lobe

primary auditory sensation, important in long-term memory, Wernicke’s area on the left hemisphere

Parietal lobe

responsible for general sensations in the body and taste

Frontal lobe

responsible for motor functions, has Broca’s area on the left hemisphere, responsible for decision making and personality

cortex and separated by longitudinal fissure

The cerebrum is covered by

Corpus Callosum

communication between right and left hemispheres via nerves

Basal forebrain

a group of structures in the forebrain important for learning and memory

Limbic cortex

region of cerebral cortex. Involved in emotion, memory, and behavior

Premotor area

responsible for thinking of movement to be made

Frontal eye fields

elicit eye movement based on visual stimuli,
Brodmann’s area

Broca’s area

responsible for the production of language (left side)

Prefrontal lobe

personality, short-term memory, and consciousness

Subcortical nuclei

the primary sight for Ach production

Hippocampus

Helps with long term memory

Amygdala

Helps with emotional response

Basal nuclei

control of voluntary movements, 3 sections (caudate, putamen, and globus pallidus) deep in cerebrum

Direct pathway

basal nuclei disinhibit thalamus (lets the thalamus send a signal to the motor cortex), activated by dopamine

Indirect pathway

reinforces the normal inhibition of the thalamus, inhibited by dopamine

All signals travel through the diencephalon except olfaction.

What is the function of the diencephalon?

The diencephalon

What structures form the walls and floor of the 3rd ventricle?

thalamus, hypothalamus, epithalamus, and subthalamus

the main components of the diencephalon?

a collection of nuclei that sends sensory information to the cerebral cortex, normally under inhibition.

function of the thalamus?

a collection of nuclei that regulate homeostasis, control autonomic and endocrine systems, and are involved in memory and emotion as part of the limbic system. It also senses light in the suprachiasmatic nucleus, regulating circadian rhythms.

function of the hypothalamus?

contains the pineal gland, which produces melatonin for sleep regulation.

What role does the epithalamus play?

midbrain and hindbrain (pons and medulla)

The main components of the brainstem?

connects the spinal cord to the rest of the brain.

function of the brainstem?

coordinates sight with touch and hearing.

What functions does the midbrain coordinate?

the cerebral peduncles (connection to thalamus), tegmentum (keeps thalamus inhibited), and tectum posterior (auditory and visual reflexes controlled by corpora quadrigemina).

What structures are contained within the midbrain?

cerebral aqueduct connects the 3rd and 4th ventricles.

the function of the cerebral aqueduct in the midbrain?

midbrain produces dopamine for the basal nuclei, and a lack of dopamine production is associated with Parkinson's disease.

What role does the midbrain play in dopamine production?

Cranial nerves III (Oculomotor) and IV (Trochlear) are associated with the midbrain.

Which cranial nerves are associated with the midbrain?

The pons connects the brainstem and cerebellum via cerebellar peduncles.

What is the function of the pons in relation to the cerebellum?

pons forms the floor of the 4th ventricle.

What structure forms the floor of the 4th ventricle?

pons acts as a bridge for ascending and descending tracts.

What role does the pons play in relation to tracts?

pons is important for REM sleep.

What is the pons' role in sleep?

Cranial nerves V (Trigeminal), VI (Abducens), VII (Facial), and VIII (Vestibulocochlear) are associated with the pons

Which cranial nerves are associated with the pons?

connects to the spinal cord

What is the role of white matter in the medulla oblongata?

regulates breathing, heart rate, and blood vessel function.

What functions does the medulla oblongata regulate?

The floor of the 4th ventricle

What does the medulla oblonga form?

where the corticospinal tracts decussate (cross over).

What are the pyramids in the medulla oblongata?

Cranial nerves IX (Glossopharyngeal), X (Vagus), XI (Accessory), and XII (Hypoglossal) are associated with the medulla oblongata.

Which cranial nerves are associated with the medulla oblongata?

it’s suppressed by depressant drugs.

How does the medulla oblongata respond to depressant drugs?

makes up 10% of the entire brain.

What percentage of the brain does the cerebellum make up?

it’s separated into hemispheres by the vermis.

How is the cerebellum divided?

has anterior and posterior lobes.

What are the main lobes of the cerebellum?

Folia(external gray matter)

What is the external structure of the cerebellum called?

Arbor Vitae(inner white matter)

What is the internal structure of the cerebellum called?

responsible for the coordination of movement and posture control.

role of the cerebellum?

a functional system in the brain composed of many components, including the amygdala, basal nuclei, fornix, mammillary body, cingulate gyrus, hippocampus, and hypothalamus.

What is the limbic system?

emotional part of the brain.

primary role of the limbic system?

Fight, Flight, Freeze, and Fawn

What does the amygdala control?

start in the medulla and end in the cortex.

Where do the neurons of the reticular formation start and end?

keeps the cortex alert and determines the level of consciousness.

What is the role of the reticular formation in the brain?

filters sensory information.

What does the reticular formation do with sensory information?

it is inhibited by alcohol and sleep-inducing drugs.

How is the reticular formation affected by alcohol and sleep-inducing drugs?

hinders long-term focus

How does ADHD affect the reticular formation?

stimulates the brain, helping to improve focus in individuals with ADHD.

How does Adderall affect the reticular formation in individuals with ADHD?