BBB and Spinal Cord

Question 1

Blood-brain barrier

Answer 1

• regulates levels of Na+/K+, AA and hormones, required environments for the brain
• incomplete in infants, increasing chances of infections
• formed by capillary, endothelium, and thick basal membrane (tight junctions between cells to prevent leakage)
• least permeable capillaries in the body

Question 2

BBB permeability

Answer 2

-allows: glucose, fats, O2, alcohol, nicotine, fat-soluble molecules to cross
-prevents: metabolites, proteins, some
Toxins and drugs
-non-essential AA and K+ ions cannot enter and are actively pumped from the brain via astrocyte feet

Question 3

Spinal cord functions

Answer 3

• two way conduction pathway to and from the brain

- centre for reflexes

Question 4

Spinal cord structure

Answer 4

• begins at the end of the medulla, through the foramen magnum
• same meningeal coverings as the brain
• includes entry and exit points for 31 spinal nerves
• runs through spinal cavity, ends between L1 and L2 (cauda equina includes spinal nerves inferior to the end of the cord)

Question 5

Spinal cord anatomy

Answer 5

-contains outer white and inner grey matter

Question 6

White matter of the spinal column

Answer 6

• (myelin sheath)
• dorsal column (ascending, sensory/afferent tracts)
• lateral column
• ventral column
• (ascending and descending, efferent tracts)

Question 7

Gray matter of the spinal cord

Answer 7

• dorsal horn (internerions, entrance of sensory neurons)
• lateral horn
• ventral horn (motor neurons of the somatic nervous System)

Question 8

Pathways between the brain and the spinal cord

Answer 8

• sensory neurons transmit messages to interneurons in spinal cord
• ascending tracts carry afferent messages
• descending tracts carry efferent messages
• motor neurons transmit messages from interneurons in the spinal cord to the effector