reticular formation, basal ganglia

Question 1

What is the reticular formation?

Answer 1

The reticular formation is a network of nerve cells and fibers in the brain, extending from the spinal cord to the brain. It connects areas of the CNS and helps control body functions, receiving sensory input and sending out messages.

Question 2

what functions does reticular formation have?

Answer 2

1. skeletal muscle control
2. facial expression
3. sensations
4. ANS
5. endocrine system
6. biological clocks
7. RAS (reticular activating system)

Question 3

What systems are influenced by the reticular formation?

Answer 3

The reticular formation influences
1. skeletal muscle activity
2. sensation
3. the autonomic nervous system (ANS),
4. endocrine system
5. consciousness.

Question 4

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Answer 4

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Question 5

How is the reticular formation organized?

Answer 5

The reticular formation is divided into three columns: median, medial, and lateral columns, each with different-sized nerve cells.

Question 6

Which chemicals are used by specialized cells in the reticular formation?

Answer 6

The reticular formation uses monoamines such as dopamine and serotonin to transmit messages.

Question 7

How does the reticular formation connect to the brain and body?

Answer 7

At its lower end, the reticular formation connects with the spinal cord’s gray matter. At the upper end, it communicates with the cerebral cortex and some fibers go to the cerebellum.

Question 8

What are the afferent projections to the reticular formation?

Answer 8

Afferent projections come from
1. spinoreticular tracts
2. spinothalamic tracts,
3. medial lemniscus
4. vestibular, auditory, visual pathways,
5. cerebellum
6. thalamus, hypothalamus, subthalamus,
7. motor and sensory cortices.

Question 9

Where do efferent projections from the reticular formation go?

Answer 9

Efferent projections go to the
1. reticulobulbar and reticulospinal tracts,
2. the ANS,
3. corpus striatum,
4. cerebellum,
5. red nucleus,
6. substantia nigra,
7. thalamus, subthalamus, hypothalamus,
8. cerebral cortex.

Question 10

What is the function of the reticular formation in muscle control?

Answer 10

The reticular formation helps control
1. muscle tone,
2. reflexes,
3. posture,
4. movement,
5. breathing muscles.

Question 11

How does the reticular formation affect facial expression?

Answer 11

It controls facial muscles, enabling expressions like smiling, even in cases where other brain areas (involving corticobulbar fibers) are damaged.

Question 12

How does the reticular formation influence sensation?

Answer 12

The reticular formation regulates how pain and other sensations are perceived by controlling a gating mechanism.

Question 13

How does the reticular formation control the ANS?

Answer 13

It regulates both the sympathetic and parasympathetic nervous systems, influencing heart rate and digestion.

Question 14

How does the reticular formation affect the endocrine system?

Answer 14

It influences hormone release by regulating the pituitary gland (hypophysis cerebri).

Question 15

What is the reticular formation’s role in biological clocks?

Answer 15

It influences internal body rhythms such as sleep-wake cycles through connections with the hypothalamus.

Question 16

What is the Reticular Activating System (RAS)?

Answer 16

The RAS, part of the reticular formation, controls alertness and consciousness by activating the cerebral cortex based on sensory inputs.

Question 17

How does the reticular formation influence consciousness?

Answer 17

The reticular formation regulates wakefulness by sending sensory information to the brain to keep it alert. Acetylcholine helps increase brain activity during wakefulness.

Question 18

What is the limbic system responsible for?

Answer 18

The limbic system controls
1. emotions
2. behavior
3. motivation
4. memory
located at the border between the cerebral cortex and hypothalamus.

Question 19

What are the key structures of the limbic system?

Answer 19

The key structures are the subcallosal gyrus, cingulate gyrus, parahippocampal gyrus, hippocampus, amygdala, mammillary bodies, and anterior thalamic nucleus.

Question 20

What are the pathways connecting the limbic system?

Answer 20

The connecting pathways are the alveus, fimbria, fornix, mammillothalamic tract, and stria terminalis.

Question 21

What is the role of the hippocampus?

Answer 21

The hippocampus processes memory, connects with other brain areas, and plays a key role in forming new memories.

Question 22

How is the hippocampus connected to other brain areas?

Answer 22

The hippocampus connects to other areas through pathways like the alveus, fimbria, and fornix.

Question 23

What does the amygdaloid nucleus (amygdala) control?

Answer 23

The amygdala controls emotional responses, such as fear and pleasure, and is connected to other parts of the limbic system.

Question 24

What are the afferent connections to the hippocampus?

Answer 24

Afferent connections to the hippocampus come from the cingulate gyrus, septal nuclei, and entorhinal cortex.

Question 25

What are the efferent connections from the hippocampus?

Answer 25

Efferent connections from the hippocampus go to areas like the mammillary bodies, thalamus, and midbrain.

Question 26

What are the functions of the limbic system?

Answer 26

The limbic system controls emotions, memory, autonomic and endocrine systems, and maintains homeostasis.

Question 27

How does the limbic system affect memory?

Answer 27

The hippocampus helps form long-term memories. Damage to the hippocampus results in anterograde amnesia, preventing the formation of new memories.

Question 28

How does the limbic system influence the autonomic and endocrine systems?

Answer 28

The limbic system regulates heart rate, digestion, and hormone release via its connection with the hypothalamus.

Question 29

How does the limbic system maintain homeostasis?

Answer 29

The limbic system responds to emotional stress and environmental changes to maintain bodily balance.

Question 30

What are the basal ganglia responsible for?

Answer 30

The basal ganglia control voluntary movements, stop unwanted movements, and are involved in cognitive functions.

Question 31

What are the five main nuclei of the basal ganglia?

Answer 31

The five main nuclei are the caudate nucleus, putamen, globus pallidus, substantia nigra, and subthalamic nucleus.

Question 32

Where is the caudate nucleus located?

Answer 32

The caudate nucleus is a C-shaped structure with a head, body, and tail, located in the cerebral hemisphere.

Question 33

What is the role of the putamen?

Answer 33

The putamen is involved in receiving input related to movement and sensory processing from the cortex.

Question 34

What is the function of the globus pallidus?

Answer 34

The globus pallidus sends inhibitory signals to the thalamus and is involved in both the direct and indirect pathways of the basal ganglia.

Question 35

How are the caudate nucleus, putamen, and globus pallidus related?

Answer 35

Together, they form the corpus striatum, which is key to motor control.

Question 36

What is the role of the substantia nigra in the basal ganglia?

Answer 36

The substantia nigra produces dopamine and is involved in regulating movement via its two parts: pars compacta and pars reticularis.

Question 37

What is the function of the subthalamic nucleus?

Answer 37

The subthalamic nucleus releases glutamate and is part of the indirect pathway in the basal ganglia.

Question 38

What are the afferent inputs to the basal ganglia?

Answer 38

The basal ganglia receive input from various parts of the cortex, with the putamen primarily receiving input from motor and sensory areas.

Question 39

What is the function of the direct pathway in the basal ganglia?

Answer 39

The direct pathway facilitates movement by disinhibiting the thalamus, allowing it to excite the motor cortex.

Question 40

What is the function of the indirect pathway in the basal ganglia?

Answer 40

The indirect pathway reduces cortical activity and suppresses unwanted movements by inhibiting the thalamus.

Question 41

How does dopamine affect the basal ganglia pathways?

Answer 41

Dopamine activates the direct pathway via D1 receptors and inhibits the indirect pathway via D2 receptors, promoting movement.

Question 42

What is the role of acetylcholine in the basal ganglia?

Answer 42

Acetylcholine promotes the indirect pathway and helps suppress unnecessary movement.

Question 43

How do lesions in the direct pathway affect movement?

Answer 43

Lesions in the direct pathway result in hypokinetic disorders, such as Parkinson's disease, causing bradykinesia and akinesia.

Question 44

How do lesions in the indirect pathway affect movement?

Answer 44

Lesions in the indirect pathway lead to hyperkinetic disorders, such as Huntington's disease, causing involuntary movements.

Question 45

What is Parkinson’s disease?

Answer 45

Parkinson's disease is a neurodegenerative disorder caused by dopamine loss in the substantia nigra, leading to hypokinetic symptoms like bradykinesia, tremors, and rigidity.

Question 46

What are the symptoms of Parkinson’s disease?

Answer 46

Symptoms include bradykinesia, pill-rolling tremor, hypertonia, cogwheel rigidity, mask-like face, and slow, shuffling gait.

Question 47

How is Parkinson’s disease treated?

Answer 47

Treatment for Parkinson’s includes L-DOPA, which is converted to dopamine in the brain.

Question 48

What is Huntington’s disease?

Answer 48

Huntington’s disease is a hereditary disorder caused by the loss of GABA and cholinergic neurons in the striatum, leading to hyperkinetic symptoms and cognitive decline.

Question 49

What are the symptoms of Huntington’s disease?

Answer 49

Symptoms include chorea, athetosis, dementia, and personality changes.

Question 50

What is hemiballismus?

Answer 50

Hemiballismus is characterized by violent, swinging movements of one limb, usually caused by a stroke affecting the subthalamic nucleus.

Question 51

What is dystonia?

Answer 51

Dystonia is a movement disorder characterized by slow, twisting movements or abnormal postures.

Question 52

What is Tourette syndrome?

Answer 52

Tourette syndrome involves both motor tics (involuntary movements) and vocal tics (involuntary sounds or words).