Organization of the Brain

Question 1

What are meninges and what are their main function in the brain?

Answer 1

Meninges are a thick sheath/layer of connective tissue that covers and protects the brain.

The meninges also keep the brain anchored within the skull and resorb cerebrospinal fluid.

Question 2

What three layers make up the meninges?

Answer 2

The meninges are composed of the dura mater, arachnoid mater and pia mater.

Question 3

What is the Dura Mater?

Answer 3

The Dura Mater is the outermost tough fibrous membrane that envelops the brain and spinal cord external to the Arachnoid and Pia mater.

The Dura Mater surrounds and supports the large venous channels (dural sinuses) carrying blood from the brain toward the heart. The dura mater is partitioned into several septa, which support the brain.

Question 4

What is the Arachnoid Mater?

Answer 4

The Arachnoid Mater has a spiderweb-like appearance and is a thin, transparent membrane surrounding the spinal cord like a loosely fitting sac.

Situated between the Dura Mater and Pia Mater, the Arachnoid Mater includes a network of fibers and collagen that are part of the suspension system that helps protect the brain and spinal cord from sudden impact.

Question 5

What is the Pia Mater?

Answer 5

The Pia Mater is the delicate innermost membrane enveloping the brain and spinal cord.

The Pia Mater closely covers the brain and acts as a barrier, and aids in the production of cerebrospinal fluid.

Question 6

What is Cerebrospinal Fluid (CSF)?

Answer 6

Cerebrospinal Fluid is the aqueous solution in which the brain and spinal cord rest.

CSF is produced by specialized cells lining the ventricles (internal cavities) of the brain.

Question 7

What are the 3 basic subdivisions of the Brain?

Answer 7

1. ) The Hindbrain
2. ) The Midbrain
3. ) The Forebrain

Question 8

What is the meaningful connection between brain location and functional complexity?

Answer 8

The brain structures associated with basic survival are located at the base of the brain and brain structures with more complex functions are located higher up.

Question 9

What is the main function of the Brainstem?

Answer 9

The Brainstem, the most primitive portion of the brain, controls the Autonomic Nervous System and communication between the spinal cord, cranial nerves and brain.

Question 10

What two subdivisions of The Brain make up the Brainstem?

Answer 10

The Brainstem, the most primitive region of the brain, is composed of the Hindbrain and the Midbrain.

Question 11

What is the Limbic System and what is their main function?

Answer 11

The Limbic System is a group of neural structures in the cerebrum primarily associated with emotion and memory.

Aggression, fear, pleasure and pain are all related to the Limbic System.

Amygdala and Hippocampus are associated with the Limbic System as well.

Question 12

What is the Cerebral Cortex?

Answer 12

The Cerebral Cortex is the outer covering of the cerebral hemispheres/cerebrum and it is responsible for complex perceptual, behavioral and cognitive processes.

It is also associated with everything from language processing to problem solving, and from impulse control to long-term planning.

Question 13

What structures are part of the Forebrain and what are their major functions?

Answer 13

1. ) Cerebral Cortex- Complex perceptual, cognitive & behavioral processes
2. ) Basal Ganglia- Movement
3. ) Limbic System- Emotion & Memory
4. ) Thalamus- Sensory relay station
5. ) Hypothalamus- Hunger and Thirst, Emotion

Question 14

What structure is part of the Midbrain and what is its major function?

Answer 14

1.) Inferior and Superior Colliculi- Sensorimotor Reflexes

Question 15

What structures are part of the Hindbrain and what are their major functions?

Answer 15

1. ) Cerebellum- Refined motor movements
2. ) Medulla Oblongata- Vital functioning (breathing, digestion)
3. ) Reticular Formation- Arousal & Alertness

Question 16

What is the process of brain development in prenatal life?

Answer 16

1. ) In prenatal life, the brain develops from the neural tube. Initially, this neural tube is composed of three swellings that correspond to the Hindbrain, Midbrain and Forebrain.
2. ) The Hindbrain & Forebrain later divide into two swellings correlating to a formation of five total swellings in the mature neural tube.

Prosencephalon (Forebrain), Mesencephalon (Midbrain) & Rhombencephalon (Hindbrain)

Question 17

What is the Forebrain called in its Prenatal Life and what two subdivisions is it composed of?

Answer 17

The Prosencephalon, or Forebrain, is divided into the Telencephalon & the Diencephalon

Question 18

What is the Midbrain called in its Prenatal Life and what subdivisions is it composed of?

Answer 18

The Midbrain is called the Mesencephalon in its Prenatal Life.

The Mesencephalon is the only division of the brain that does not have any subdivisions, unlike its counterparts.

Question 19

What is the Hindbrain called in its Prenatal Life and what two subdivisions is it composed of?

Answer 19

The Hindbrain is called the Rhombencephalon in its Prenatal Life.

The Rhombencephalon is subdivided into the Metencephalon and the Myelencephalon.

Question 20

What structures do the subdivisions of the Rhombencephalon (Hindbrain) subsequently develop into?

Answer 20

The Myelencephalon & Metencephalon are the two subdivisions of the Rhombencephalon.

The Myelencephalon later develops into the Medulla Oblongata

The Metencephalon later develops into the Pons & Cerebellum

Question 21

What is the main functions of the Hindbrain?

Answer 21

The Hindbrain (Rhombencephalon) is located where the brain meets the spinal cord.

The Hindbrain controls balance, motor coordination, breathing, digestion and general arousal processes such as sleeping and walking.

Overall, the functions controlled by the Hindbrain are vital for survival

In Prenatal development, the Rhombencephalon divides into the Myelencephalon and Metencephalon.

Question 22

What is the function of the Medulla Oblongata?

Answer 22

The Medulla Oblongata is the lower brain structure that is responsible for regulating vital functions such as breathing, heart rate and blood pressure.

Question 23

What is the function of the Pons?

Answer 23

The Pons lies above the Medulla Oblongata.

The Pons is a portion of the brainstem that relays information between the cortex and medulla, regulates sleep and carries some motor and sensory information from the face and neck.

Question 24

What is the function of the Cerebellum?

Answer 24

The Cerebellum is a portion of the hindbrain that maintains posture and balance and coordinates body movement.

Damage to the Cerebellum causes clumsiness, slurred speech and loss of balance.

Question 25

What is the main functions of the Midbrain?

Answer 25

The Midbrain (Mesencephalon) is located just above the Hindbrain.

The Midbrain is the portion of the brainstem that manages sensorimotor reflexes to visual & auditory stimuli and gives rise to some cranial nerves.

The Midbrain contains several prominent nuclei in the midbrain which are collectively called colliculi.

Question 26

What are Colliculi?

Answer 26

Colliculi are two structures in the Midbrain involved in sensorimotor reflexes.

The two structures are the Superior Colliculi and the Inferior Colliculi.

Question 27

What is the main function of the Superior Colliculi?

Answer 27

The Superior Colliculi is a structure in the Midbrain that receives visual input and impacts eye movements and object oriented behaviors.

Question 28

What is the main function of the Inferior Colliculi?

Answer 28

The Inferior Colliculi is the region of the Midbrain that receives and integrates sensory input from the auditory system, and is involved in reflexive reactions to auditory input.

Question 29

What are the main functions of the Forebrain?

Answer 29

The Forebrain (Prosencephalon) is located above the Midbrain.

The Forebrain is a portion of the brain that is associated with complex perceptual, cognitive and behavioral processes such as emotion and memory.

The Forebrain’s functions are not essential for survival, but are associated with the intellectual and emotional capacities most characteristic of humans.

During Prenatal Development, the Prosencephalon divides to form the Telecephalon and Diencephalon.

Question 30

MCAT Concept Check:

What are the main functions of the Hindbrain, Midbrain & Forebrain?

Answer 30

1. ) Hindbrain: controls balance, motor coordination, breathing, digestion and general arousal processes such as sleeping and walking.
2. ) Midbrain: portion of the brainstem that manages sensorimotor reflexes to visual & auditory stimuli and gives rise to some cranial nerves.
3. ) Forebrain: portion of the brain that is associated with complex perceptual, cognitive and behavioral processes such as emotion and memory.