Lecture 2 T1 CNS structure and function

Question 1

What is the function of acetylcholine?

Answer 1

usually excitatory

Question 2

What secretes acetylcholine?

Answer 2

• pyramidal cells of cerebral cortex,
• some neurons in the basal nuclei,
• alpha motor neurons,
• preganglionic neurons of ANS,
• postganglionic neurons of the parasympathetic system,
• some postganglionic neurons of the sympathetic system

Question 3

What targets ACh?

Answer 3

nicotine, chantix, sarin, aricept (alzheimers), botox, tensolin (myasthenia gravis), biperiden (parkinsons).

Question 4

What is the function of norepinephrine?

Answer 4

can be excitatory or inhibitory

Question 5

What secretes norepinephrine?

Answer 5

• many neurons located in the brainstem and hypothalamus,
• some neurons located in the pons (locus ceruleus),
• most postganglionic neurons of the sympathetic system

Question 6

What is the function of dopamine?

Answer 6

usually inhibitory

Question 7

What secretes dopamine?

Answer 7

Most neurons originating the in the substantia nigra

Question 8

What is norepinephrine targeted by?

Answer 8

amphetamines, cocaine, cymbalta, propranolol.

Question 9

What is dopamine targeted by?

Answer 9

amphetamines, cocaine, levadopa (parkinsons), haldol (antipsychotic).

Question 10

What is the function of glycine?

Answer 10

always inhibitory

Question 11

What secretes glycine?

Answer 11

synapses in the spinal cord

Question 12

What is the function of GABA?

Answer 12

always inhibitory

Question 13

What secretes GABA?

Answer 13

many areas in the spinal cord and cerebral cortex

Question 14

What is the function of glutamate?

Answer 14

always excitatory

Question 15

What secretes glutamate?

Answer 15

• many sensory pathways entering the CNS,

- many areas of cerebral cortex

Question 16

What are the targets of Glycine?

Answer 16

not a drug target

Question 17

What are the targets of GABA?

Answer 17

alcohol, barbituates, valium, bacloden

Question 18

What are the targets of Glutamate?

Answer 18

ketamine, namenda, robitussin

Question 19

What type of conduction occurs in dendrites?

Answer 19

decremental conduction

Question 20

What is decremental conduction?

Answer 20

The signal becomes weaker the further it is from the site of initiation. This is opposite to action potentials, which are constantly renewed along the length of the axon and do not decrease in strength.

Question 21

What is electrotonic conduction?

Answer 21

direct spread of electrical current by ion conduction in the dendritic fluids without generating an action potential

Question 22

What are the dendritic characteristic that result in electrotonic conduction?

Answer 22

few voltage-gated sodium channels in dendritic membranes, and thresholds too high for action potentials to occur.

Question 23

Explain the firing rate of dendrites.

Answer 23

As long as the excitatory rate of a neuron remains above the threshold for excitation, the neuron will fire repeatedly. The firing rate depends on the normal excitatory rate and on the changes in the excitatory rate due to superimposition of additional excitatory or inhibition signals.

Question 24

In reference to dendrites, what is synaptic delay? and what is the synaptic delay?

Answer 24

Synaptic delay refers to the time it takes to transmit a signal from a presynaptic neuron to a postsynaptic neuron. The minimal synaptic delay of a dendrite is 0.5 second.

Question 25

What are the two sources of blood supply to the brain?

Answer 25

Vertebral arteries and internal carotids

Question 26

What is the circle of willis?

Answer 26

pentagonal-shaped circle of arteries on the ventral surface of the brain that unites the two vertebral and the two internal carotid arteries.

Question 27

What is the anastomosis between the two vertebral arteries and the two internal carotid arteries in the brain?

Answer 27

The circle of willis

Question 28

What is the function of the occipital lobe?

Answer 28

Integrates eye focusing movements, correlates visual images with visual memory, and involved in conscious perception of vision.

Question 29

What is the function of the parietal lobe?

Answer 29

Somatesthetic interpretation (postcentral gyrus), understanding speech (auditory cortex and wernickes area), formulating words to express thoughts and emotions.

Question 30

What is the landmark that separates the motor cortex from the sensory cortex?

Answer 30

Central sulcus.

Question 31

What are the functions of the frontal lobe?

Answer 31

• voluntary motor control (precentral gyrus)
• motivation
• aggression
• mood
• personality
• cognitive processes
• verbal communication (broca’s area)

Question 32

What is the function of the temporal lobe?

Answer 32

• receives/interprets olfactory and auditory sensations

- responsible for storage of memory related to auditory and visual experiences.