Biology CNS

Question 1

What physical role does CSF play in protecting the brain?

Answer 1

CSF acts as a cushion or shock-absorber for the brain, and due to the specific gravity of the brain (1.040) and CSF (1.007), it renders the brain buoyant, effectively reducing the weight of the brain, which helps in reducing acceleration-deceleration injuries.

Question 2

How does CSF contribute to the neuronal and glial environment?

Answer 2

CSF provides an appropriate local environment for neurons and glia, which is crucial for their optimal functioning.

Question 3

What is the role of CSF in the exchange between brain ECF and systemic blood?

Answer 3

CSF serves as a medium of exchange between brain extracellular fluid (ECF) and systemic blood, allowing for the transport of nutrients and removal of waste products.

Question 4

How does CSF assist in waste removal from the brain?

Answer 4

CSF facilitates the removal of waste products from brain metabolism, drugs, and neurotransmitter metabolites.

Question 5

What role does CSF play in relation to the brain and peripheral endocrine functions?

Answer 5

CSF provides an interface between the brain and peripheral endocrine functions, including the transport of releasing hormones from the hypothalamus.

Question 6

What is the brain made of?

Answer 6

Glial cells

Question 7

Why is folic acid important during pregnancy?

Answer 7

Folic acid supplementation is crucial in preventing neural tube defects like spina bifida and anencephaly. It is recommended for women of childbearing age to take folic acid before conception and during early pregnancy to reduce the risk of these fetal conditions.

Question 8

How are neurons and glial cells formed in the CNS?

Answer 8

Stem cells from the ectoderm layer differentiate into progenitor cells, which then become lineage-restricted progenitor cells.
These can further differentiate into neurons, oligodendrocytes, and astrocytes.
Neurons are responsible for signaling, oligodendrocytes for myelination, and astrocytes for supporting neuronal function and maintaining the blood-brain barrier.

Question 9

What are the main parts of the brainstem and their primary functions?

Answer 9

The brainstem consists of the medulla (controls respiration and circulation),
the pons (bridge for brain signals and autonomic control, related to sleep and arousal), and the midbrain (controls body movement and contains the substantia nigra important for movement and Parkinson’s disease).

Question 10

What is the function of the cerebellum?

Answer 10

The cerebellum, or ‘little brain,’ coordinates fine muscle movements and balance, contributing to the precision and timing of motor actions.

Question 11

What roles does the hypothalamus play in the brain?

Answer 11

The hypothalamus regulates autonomic functions such as cardiovascular and temperature control, appetite, sexual behavior, and sleep. It also controls hormone release via the pituitary gland.

Question 12

How does cannabis affect appetite?

Answer 12

Cannabis can stimulate receptors in the hypothalamus, leading to increased appetite, known as the ‘munchies’.

Question 13

What role does the hypothalamus play in sexual function?

Answer 13

The hypothalamus is involved in sexual functioning and arousal, and its dysfunction can contribute to erectile dysfunction.

Question 14

How can the hypothalamus contribute to eating disorders?

Answer 14

The hypothalamus regulates appetite and energy expenditure, and its dysfunction can be associated with conditions such as anorexia.

Question 15

What causes diabetes insipidus?

Answer 15

Diabetes insipidus can result from the hypothalamus producing insufficient ADH, or the pituitary gland releasing inadequate ADH, leading to water balance issues.

Question 16

How might the hypothalamus be involved in developmental disorders?

Answer 16

The hypothalamus influences hormone release from the pituitary gland, affecting growth and development; disorders in these processes can result in developmental issues.

Question 17

What is the function of the thalamus in the brain?

Answer 17

The thalamus acts as the brain’s sensory switchboard, relaying sensory information to and from the cortical regions. It plays a key role in processing and directing sensory signals, as well as in motor control.

Question 18

What is the role of the basal ganglia in movement, and how does it relate to Parkinson’s disease?

Answer 18

The basal ganglia coordinate smooth muscle movements and inhibit unnecessary ones. In Parkinson’s disease, the death of dopaminergic neurons in the basal ganglia disrupts normal movement control, leading to symptoms such as tremors and difficulty walking.

Question 19

What are the two synapses in nervous system?

Answer 19

Chemical synapses
Electrical synapses

Question 20

What are the differences between chemical and electrical synapses?

Answer 20

Chemical synapses use neurotransmitters to communicate between neurons and involve a complex process of release, binding, and receptor activation, which can be either fast or slow. Electrical synapses use gap junctions for direct ion flow, allowing for faster and bidirectional communication but are less common than chemical synapses.

Question 21

What is an example of inhibitory neurotransmitter?

Answer 21

GABA

Question 22

Explain Excitatory chemical synapses

Answer 22

The use of glutamate as neurotransmitter and binds to receptors on postsynaptic neuron leading to depolirization and action potential

Question 23

Explain inhibitory chemical synapses

Answer 23

Use GABA asa neurotransmitter that binds to receptors allow CL- chloride ions into neurom leading to hyperpolarization and inhibition of action potential.

Question 24

Examples of Catecholamines

Answer 24

Dopamine
Adrenaline
Nonadrenaline

Question 25

What are the differences between excitatory and inhibitory synapses?

Answer 25

What are the differences between excitatory and inhibitory synapses?

Question 26

How is acetylcholine synthesized and terminated in the synaptic cleft?

Answer 26

Acetylcholine is synthesized from acetyl CoA and choline by choline acetyltransferase, stored in vesicles, released by exocytosis, and terminated by acetylcholinesterase, which breaks it down into acetate and choline.

Question 27

How are catecholamines and serotonin synthesized?

Answer 27

Catecholamines are synthesized from tyrosine, while serotonin is made from tryptophan,

Question 28

What is the pathway of dopamine synthesis affected in Parkinson’s disease?

Answer 28

Parkinson’s disease affects dopamine synthesis, which follows the pathway: Tyrosine → L-DOPA → Dopamine. The disease is characterized by the depletion of dopamine, and Levodopa is used to increase its levels.

Question 29

How is serotonin synthesized, and what role does it play in mood disorders?

Answer 29

Serotonin is synthesized from tryptophan via 5-HTP and is involved in the regulation of mood. It is a target for the treatment of anxiety and depression. Serotonin’s action is terminated by enzymes such as MAO and COMT.

Question 30

How do amphetamines and MDMA affect neurotransmitter release?

Answer 30

Amphetamines cause a non-exocytotic release of NA and DA, while MDMA causes increased release of 5-HT, DA, and NA. These drugs can lead to overactivation of receptors and excessive neurotransmitter release, resulting in their psychoactive effects.

Question 31

How does donepezil affect neurotransmitter termination in Alzheimer’s disease?

Answer 31

Donepezil inhibits acetylcholinesterase, the enzyme that breaks down acetylcholine, resulting in increased levels of acetylcholine in the brain to help improve cognitive function in Alzheimer’s patients.

Question 32

How is serotonin termination affected in the treatment of anxiety and depression?

Answer 32

The termination of serotonin’s action is primarily by reuptake into the presynaptic neuron. Antidepressants often inhibit this reuptake, increasing serotonin levels and activity to help alleviate symptoms of mood disorders.