CNS Review

Question 1

What is the forebrain associated with?

Answer 1

The highest intellectual functions such as thinking, planning, problem solving and speech

Question 2

Anatomy of the cerebral cortex

Answer 2

Consists of two hemispheres (right and left) that are joined by the corpus callosum and make up the cerebrum. The outer layer of the cerebrum is the cerebral cortex, which is folded for more surface area.

Question 3

What does the left hemisphere control

Answer 3

The left hemisphere controls the right side of the body (analytical thinking, problem solving, and language).

Question 4

What does the right hemisphere control

Answer 4

The right hemisphere controls the left side of the body (artistic expression and spatial relationships).

Question 5

Cortical homunculus

Answer 5

The cortical homunculus shows that not an equal amount of cortex is dedicated to specific functions

Question 6

Limbic system

Answer 6

An assembly of regions: amygdala (governs emotions – self-preservation), hippocampal formation (formation of new memories), septum, olfactory nuclei, basal ganglia and selected nuclei of the diencephalon

Question 7

Diencephalon

Answer 7

the thalamus and the hypothalamus

Question 8

Role of thalamus

Answer 8

The thalamus acts as a relay station for almost all sensory information coming from the periphery to the brain and regulates higher brain centers

Question 9

Role of the hypothalamus

Answer 9

The hypothalamus serves as the principal integrating region for internal regulatory systems, stress reactions, emotion, and motivation. It receives information from the autonomic nervous system and regulates the body (ie temperature, sleep, circadian and sexual cycles) via the nerves and pituitary

Question 10

Role of the midbrain

Answer 10

coordinates visual and auditory input from sense organs (ie eye movements)

Question 11

Role of the medulla

Answer 11

Medulla controls heart rate, respiration, and blood pressure

Question 12

Role of the pons

Answer 12

Pons receives information and decides where to send it to be processed (can override sensory information). Controls sleep, awakening cycles, and dream impulses

Question 13

Role of the hindbrain

Answer 13

Hindbrain also controls body temperature, simple reflexes (coughing and sneezing) and digestion.

Question 14

Reticular Activating System/Reticular Formation

Answer 14

A diffuse network of neurons in the medulla, pons, and midbrain that are essential for sleep, arousal, and wakefulness. They also coordinate reflex acts such as swallowing, vomiting, respiration, and those involving the cardiovascular system

Question 15

Role of the cerebellum

Answer 15

coordinates movement, posture, and balance

Question 16

Role of the spinal cord

Answer 16

Receives sensory information from, and sends motor information to the trunk, limbs and many of the organs

Question 17

Central Pattern Generators

Answer 17

The spinal cord contains Central Pattern Generators (CPG) Networks that can be recruited locally (ie perform a reflex action or coordinate movement) and don’t require sensory input from higher brain centers. CPGs are also located outside of the spinal cord to control some aspects of breathing, eye movement, and swallowing

Question 18

Role of nociceptors

Answer 18

detect pain

Question 19

Role of mechanoreceptors

Answer 19

detect pressure, touch, movement, vibration, and tension

Question 20

Role of proprioceptors

Answer 20

“receptors for self”, continuous information about body position and limbs in space

Question 21

Blood-brain barrier

Answer 21

the tight seal of cells that lines the blood vessels in the brain

Question 22

Anatomy of the blood brain barrier

Answer 22

Endothelial cells are the principle anatomic site of the blood-brain barrier characterized by tight junctions. They are distinct from general (systemic) capillaries. Glial cells also wrap around the capillaries

Question 23

Neuron

Answer 23

the basic working unit of the CNS

Question 24

What is the major excitatory neurotransmitter

Answer 24

glutamate

Question 25

What is the major inhibitory neurotransmitter

Answer 25

GABA

Question 26

Divergent Pathway

Answer 26

one presynaptic neuron branches to affect a larger number of postsynaptic neurons

Question 27

Convergent Pathway

Answer 27

many presynaptic neurons converge to influence a smaller number of postsynaptic neurons

Question 28

How are neurons classified

Answer 28

Neurons are classified by function (sensory, motor, interneuron), location, identity of the neurotransmitter they synthesize and release (serotonin, acetylcholine, etc), and the identity of the receptor class they express (what neurotransmitter they respond to

Question 29

Criteria to be considered a neurotransmitter

Answer 29

Present in presynaptic terminals arising from an identified neuron
Released from the presynaptic terminal in a manner consistent with presynaptic “nerve” activity
When administered exogenously the effects should be identical to the action of the endogenous transmitter
Specific agonists and antagonists should mimic and antagonize, respectively, the defined action of the drug with appropriate affinities and order of potency

Question 30

Order of events for cell signaling and synaptic transmission

Answer 30

1. Synthesis
2. Storage in a presynaptic vesicle
3. Release via exocytosis from the active zone (central part where all the vesicles come through). Caused by depolarization which leads to calcium influx and calcium dependent binding and docking of vesicles. The vesicles bind to the SNARE protein complex, which has three critical components: synaptobrevin/VAMP, syntaxin, and SNAP-25. Changes in SNARE expression has been described in several CNS disorders.
4. Transmitter interaction with a receptor initiates a signal transduction event
5. Removal of the transmitter from the synapse leads to termination of the signal (enzymatic and reuptake; diffusion and degradation for peptides and gases)

Question 31

Voltage gated ion channels

Answer 31

Electrical excitability of neurons is dictated by modification of ion channels in the plasma membrane. Cation channels include sodium, potassium, and calcium. Anion channels include chloride

Question 32

Small molecule neurotransmitters

Answer 32

acetylcholine, norepinephrine, dopamine, and serotonin

Question 33

Amino acid neurotransmitters

Answer 33

GABA, glutamate, glycine

Question 34

Neuroactive peptides neurotransmitters

Answer 34

ie opioid peptides, most act at GPCR