Functional Brain Systems

Question 1

What is the LIMBIC SYSTEM?

Answer 1

A ring of structures around CORPUS CALLOSUM and THALAMUS

• Center of emotion and learning
• Connects logic, thoughts (PREFRONTAL CORTEX) with: emotions (HYPOTHALAMUS, AMYGDALA), memory and learning (HIPPOCAMPUS), and visceral well-being (HYPOTHALAMUS)

Question 2

What is RETICULAR FORMATION and what does it do?

Answer 2

• Web of GREY MATTER that runs throughout the BRAIN
• Filters out 99% of signals to prevent sensory overload
• Stimulates CORTEX, keeps consciousness
• Inhibited by sleep centers
• Depressed by alcohol and tranquilizers
• Damage can result in irreversible coma

Question 3

What 4 things help to protect the BRAIN?

Answer 3

1) SKULL
2) MENINGES
3) CSF
4) BLOOD-BRAIN BARRIER

Question 4

What does the MENINGES do?

Answer 4

• Covers and protects CNS
• Protect blood vessels, enclose sinuses
• Contain CSF
• Form partitions

Question 5

What is the MENINGES made up of?

Answer 5

3 layers of connective tissue membranes, the:

• FALX CEREBRI
• TENTORIUM CEREBELLI
• FALX CEREBELLI

Question 6

What does the FALX CEREBRI do?

Answer 6

It separates hemi’s and attaches to CRISTA GALLI

Question 7

What does the FALX CEREBELLI do?

Answer 7

It separates CEREBELLAR HEMI’S

Question 8

What does the TENTORIUM CEREBELLI do?

hint: TENTORIUM

Answer 8

It’s in the TRANSVERSE FISSURE and it covers the CEREBELLUM

Question 9

What is the function of the DURAL SINUS?

Answer 9

CSF and venous blood drain into veins here.

Question 10

What is the structure and function of the ARACHNOID VILLI?

Answer 10

They are little projections of ARACHNOID MATER. Their function is to return CSF to venous blood in DURAL SINUS

Question 11

What can be found in the SUBDURAL SPACE?

Answer 11

SEROUS FLUID

Question 12

What is typically found in the SUBARACHNOID SPACE?

Answer 12

CSF and large blood vessels

Question 13

What is ARACHNOID MATER?

Answer 13

A middle membrane made of loose, web-like anchors

Question 14

What are the 2 layers of the DURA MATER?

Answer 14

1) PERIOSTEAL LAYER
2) MENINGEAL LAYER
They are fused together EXCEPT at the DURAL SINUS

Question 15

What is the function of the PERIOSTEAL LAYER?

Answer 15

It attaches to the SKULL

Question 16

What is the function of the MENINGEAL LAYER?

Answer 16

It covers the BRAIN

Question 17

What is the structure and function of the PIA MATER?

Answer 17

It’s a delicate membrane that organizes capillaries. It is the deepest membrane and it follows every convolution of the surface of the BRAIN

Question 18

What is CSF and where is it found?

Answer 18

• Found in ventricles of the BRAIN and central canal of SPINAL CORD
• Reduces weight
• Cushions and absorbs shock and blows
• Removes waste and maintains environment around NEURONS
• Similar to PLASMA but less protein, glucose, K+, Ca+, more Na+ and Cl-, no hormones.

Question 19

How is CSF formed?

Answer 19

Fluid leaves permeable capillaries of CHOROID PLEXUS (L= wall of ventricles) and is filtered by ependymal cells connected by tight junctions

Question 20

Explain CSF circulation.

Answer 20

• CSF forms, enters, flows through ventricles
• Exits ventricles via medial and 2 lateral apertures of 4th ventricle
• Enters SUBARACHNOID SPACE, bathes BRAIN and SPINAL CORD
• Enters ARACHNOID VILLI
• Transferred to DURAL SINUS
• Returned to blood via jugular vein

Question 21

What is the function of the BLOOD-BRAIN BARRIER?

It’s a longgg one

Answer 21

• Maintains a stable environment of ECF for the BRAIN
• Ions, hormones, amino acids, wastes, toxins, can overexcite the BRAIN
• least permeable capillaries in body
• Only gases, lipid-soluable molecules (e.g. alcohol, caffine, nicotine, etc.) can pass through
• Glucose, amino acids, ions, and water must be transported
• Astrocytes maintain impermeability
• Exists everywhere except where BRAIN needs to sample blood environment (e.g. vomiting center in MEDULLA OBLONGATA to detect toxins or HYPOTHALAMUS to detect water balance, ion concentration, release hormones, pH