BIOL 318: CH. 14 - GREY MATTER & BRAIN

What is grey matter composed of?

Grey matter is composed of neurosomas, dendrites, and synapses, and is involved in processing and integration of information.

What are neurosomas in grey matter responsible for?

Neurosomas in grey matter are responsible for processing and integrating signals.

What role do dendrites play in grey matter?

Dendrites in grey matter receive signals from other neurons and transmit them to the neurosoma.

What is the function of synapses in grey matter?

Synapses in grey matter allow communication between neurons, where signals are transmitted from one neuron to another.

What does the cortex and integration centers in grey matter do?

The cortex and integration centers in grey matter are involved in complex processing tasks like thought, perception, and decision-making.

What is white matter composed of?

White matter is composed of tracts of axons that transmit signals between different parts of the nervous system.

What are tracts of axons in white matter responsible for?

Tracts of axons in white matter are responsible for transmitting electrical signals between different regions of the brain and spinal cord.

What is the significance of myelinated axons in white matter?

Myelinated axons in white matter increase the speed of signal transmission by insulating the axons.

What function does white matter serve in relation to signal transmission?

White matter relays signals between different parts of the nervous system, facilitating communication throughout the body.

What is the surface layer of the brain called?

The surface layer of the brain is called the cerebral cortex.

What type of matter is the cerebral cortex made of?

The cerebral cortex is made of grey matter of the telencephalon.

What are the two major types of neurons in the cerebral cortex?

The two major types of neurons in the cerebral cortex are stellate cells and pyramidal cells.

What is the structure and function of stellate cells?

Stellate cells are spherical with short dendrites and axons, and they receive input from afferent fibers.

What is the function of pyramidal cells in the cerebral cortex?

Pyramidal cells synapse with other cortical neurons and are output neurons.

What do pyramidal cell axons do?

Some axons of pyramidal cells leave the cortex to connect with other regions.

How does the thickness of the cerebral cortex vary?

The thickness of the cerebral cortex varies based on the function of the area.

What is the largest volume of cerebral white matter made up of?

The largest volume of cerebral white matter is made up of glia and myelinated fibers.

What is the function of cerebral white matter?

Cerebral white matter transmits signals between and within areas of the brain.

What are the three types of tracts in cerebral white matter?

The three types of tracts in cerebral white matter are projection tracts, commissural tracts, and association tracts.

What is the function of projection tracts in the cerebral white matter?

Projection tracts are vertical tracts that connect the brain to the spinal cord and other areas of the central nervous system.

What do commissural tracts do in the cerebral white matter?

Commissural tracts bridge communication between the hemispheres of the brain, with the corpus callosum being a primary example.

What is the role of association tracts in the cerebral white matter?

Association tracts connect regions within the same hemisphere of the brain.

What is the function of the hindbrain?

The hindbrain is involved in basic life-sustaining functions such as heart rate, respiration, and balance.

What is the role of the medulla oblongata?

The medulla oblongata regulates vital functions such as heart rate, blood pressure, and respiration.

What is the myelencephalon?

The myelencephalon is the embryonic structure that gives rise to the medulla oblongata.

What are the pyramids in the brainstem?

The pyramids are structures located in the medulla oblongata that contain corticospinal tracts, which are involved in motor control.

What is the function of the axons of the gracile and cuneate fasciculi?

The axons of the gracile and cuneate fasciculi transmit sensory information from the body to the brain, specifically touch and proprioception.

What does it mean for the axons of the gracile and cuneate fasciculi to decussate?

Decussation refers to the crossing of the sensory axons from one side of the body to the opposite side in the medulla, which is part of the pathway to the thalamus.

What is the function of the medial lemniscus?

The medial lemniscus is a pathway in the brainstem that transmits sensory information, particularly touch and proprioception, to the thalamus.

How does the thalamus relate to the cortex?

The thalamus acts as a relay station for sensory information, sending it to the appropriate areas of the cortex for processing.

What are the corticospinal tracts?

The corticospinal tracts are motor pathways that transmit voluntary movement signals from the cerebral cortex to the spinal cord.

What is the function of the inferior olivary nucleus?

The inferior olivary nucleus acts as a relay center, sending signals between the brain and spinal cord, particularly involved in motor coordination with the cerebellum.

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What is the role of the pons?

The pons helps relay signals between the cerebrum and cerebellum, contributing to motor control and sensory analysis.

What is the metencephalon?

The metencephalon is a part of the hindbrain that includes the pons and cerebellum, involved in motor control and sensory processing.

What are cerebellar peduncles?

Cerebellar peduncles are bundles of nerve fibers that connect the pons and mesencephalon to the cerebellum, facilitating communication.

What is the function of transverse and longitudinal tracts in the cerebellum?

Transverse and longitudinal tracts are involved in communication between the cerebellum and other brain areas, assisting in sensory and motor information processing.

How does the cerebellum communicate with itself and process sensory information?

The cerebellum communicates with itself through pathways that help manage coordination, balance, and sensory information, sending sensory input upward.

What functions are controlled by cranial nerves 5 to 8?

Cranial nerves 5 to 8 control functions like facial sensation, chewing, salivation, urination, hearing, and equilibrium.

What is the midbrain, and where is it located?

The midbrain is a part of the brainstem located between the forebrain and hindbrain, responsible for regulating motor movement and visual and auditory processing.

What is the mesencephalon?

The mesencephalon is the embryonic structure that develops into the midbrain in adults.

What are the corpora quadrigemina, and what function do they serve?

The corpora quadrigemina are four bumps on the dorsal side of the midbrain, involved in processing visual and auditory information.

What is the tectum, and where is it located?

The tectum is the dorsal part of the midbrain, containing structures like the superior and inferior colliculi, which are involved in sensory processing.

What is the significance of the grey matter surrounding the midbrain?

The grey matter surrounding the midbrain consists of neuron cell bodies and plays a crucial role in sensory processing and motor control.

What are the cerebral peduncles, and what do they connect?

The cerebral peduncles are bundles of nerve fibers that connect the cerebrum to the brainstem, transmitting motor and sensory signals.

What is the function of the oculomotor nucleus?

The oculomotor nucleus controls the muscles responsible for eye movement and pupil constriction.

Which cranial nerves are associated with the midbrain, and what are their functions?

Cranial nerves III (oculomotor) and IV (trochlear) are associated with the midbrain. CN III controls eye movement and pupil constriction, while CN IV controls eye movement.

What is the role of the reticulospinal tracts in pain sensation?

The reticulospinal tracts carry pain signals from the spinal cord to the brain, particularly contributing to the sensation of pain.

What is the red nucleus, and what is its function?

The red nucleus is a structure in the midbrain involved in motor coordination and fine motor control.

What role do blood vessels play in the midbrain?

Blood vessels supply oxygen and nutrients to the midbrain and remove waste products, supporting its function.

How do the tracts with cerebellum affect motor control?

The tracts connecting the midbrain to the cerebellum are involved in coordinating fine motor control and balance.

What is the involvement of the midbrain in fine motor control?

The midbrain, particularly the red nucleus and its connections to the cerebellum, plays a critical role in the regulation of fine motor control.

What is the substantia nigra?

The substantia nigra is a structure in the midbrain that produces dopamine and plays a crucial role in controlling movement, with its degeneration being linked to Parkinson's disease.

What is the role of the inhibitory motor function to the thalamus?

The inhibitory motor function to the thalamus helps regulate the transmission of motor signals to the cortex, controlling voluntary movement and preventing unwanted movements.

What are the cerebral crus?

The cerebral crus are a pair of large bundles of nerve fibers that connect the cerebrum to the brainstem, carrying motor information from the cerebral cortex to other parts of the nervous system.

What is the reticular formation (RF) and where is it located?

The reticular formation (RF) is a network of neurons found in the brainstem, specifically in the midbrain, pons, and medulla oblongata.

What functions are associated with the reticular formation (RF)?

The reticular formation (RF) is involved in somatic motor control, pain control, sleep and consciousness, and habituation.

What are the reticulospinal tracts responsible for?

The reticulospinal tracts are responsible for posture and balance during movement.

How does the reticular formation contribute to breathing and throat muscle control?

The reticular formation contains networks of central pattern generators (CPGs) that control breathing and throat muscles.

What role does the reticular formation play in pain control?

The reticular formation plays a role in pain control by processing pain signals and utilizing pain inhibitory neurons.

What role does the reticular formation play in sleep and consciousness?

The reticular formation plays a key role in regulating sleep and consciousness by controlling projections into the thalamus and influencing the signals that reach the cerebrum.

What happens when there is damage to the reticular formation?

Damage to the reticular formation can lead to an irreversible coma.

What is habituation?

Habituation is the process of learning what signals are important and which are not.

What is the mass percentage of the cerebellum in the brain?

The cerebellum accounts for 10% of the mass of the brain.

How much surface area does the cerebellum have compared to its mass?

The cerebellum has 60% as much surface area as its mass.

What percentage of all brain neurons are found in the cerebellum?

The cerebellum contains more than 50% of all brain neurons.

What function is the cerebellum responsible for in relation to muscle coordination?

The cerebellum plays a key role in muscle coordination by integrating sensory input with muscle movement.

How does the cerebellum contribute to balance and equilibrium?

The cerebellum is involved in maintaining equilibrium and balance.

What role does the cerebellum play in tactile exploration?

The cerebellum is important for tactile exploration, allowing for the 3D understanding of objects.

How does the cerebellum assist in time coordination?

The cerebellum helps in coordinating time by evaluating timing and sequencing of movements.

What role does the cerebellum have in sound interpretation and language output?

The cerebellum is involved in interpreting sound and contributing to language output.

What is the thalamus responsible for?

The thalamus acts as a relay station, transmitting sensory and motor signals to the cerebral cortex.

Where is the thalamus located?

The thalamus is located in the diencephalon, which is part of the brain.

What role does the thalamus play in sensory input?

The thalamus serves as the gateway to the cerebral cortex, where input from sensory systems like smell, vision, taste, touch, pressure, and temperature passes through.

How does the thalamus contribute to sensory processing?

The thalamus filters out unimportant sensory information before sending relevant data to the cortex.

What function does the thalamus have in motor control?

The thalamus is involved in motor control pathways, receiving input from the basal nuclei to refine and modulate motor signals before sending them to the cortex.

How does the thalamus affect descending motor pathways?

The thalamus helps control descending motor pathways, which are responsible for directing motor responses.

Does the thalamus have a role in memory?

Yes, the thalamus is involved in memory functions by helping process and relay information related to memory.

Where is the hypothalamus located?

The hypothalamus is located beneath the thalamus in the diencephalon.

What is the function of the hypothalamus in relation to the endocrine system?

The hypothalamus serves as the endocrine control center by secreting hormones that control the anterior pituitary.

How does the hypothalamus contribute to homeostasis?

The hypothalamus plays a key role in the homeostatic regulation of organs, maintaining balance in the body.

What role does the hypothalamus have in thermoregulation?

The hypothalamus is involved in thermoregulation by helping to regulate body temperature.

How does the hypothalamus regulate hunger and thirst?

The hypothalamus regulates hunger and thirst by detecting changes in the body and initiating the appropriate responses.

How does the hypothalamus relate to memory?

The hypothalamus is part of memory pathways, connecting the hippocampus with the thalamus.

What is optogenetics?

Optogenetics is the use of light-gated ion channels to control the activity of genetically modified neurons in a living animal.

What does the paraventricular nucleus control?

The paraventricular nucleus is involved in the regulation of hormone release, particularly oxytocin and vasopressin.

What is the function of oxytocin?

Oxytocin plays a role in social bonding, childbirth, and lactation by stimulating uterine contractions and milk release.

What is the role of the supraoptic nucleus in the body?

The supraoptic nucleus produces vasopressin (ADH), which helps regulate water balance in the body.

What does ADH do?

ADH (antidiuretic hormone) helps the kidneys conserve water by reducing urine production.

What function is the anterior nucleus involved in?

The anterior nucleus helps regulate body temperature by triggering sweating and vasodilation when the body is overheated.

What triggers the sensation of thirst?

Thirst is triggered when the body detects dehydration or an imbalance in the concentration of salt in the blood.

What does the ventromedial nucleus regulate?

The ventromedial nucleus is associated with satiety and helps regulate feelings of hunger and fullness.

How does the ventromedial nucleus influence hunger?

The ventromedial nucleus signals when the body has had enough food, helping to suppress hunger.

What role does the preoptic nucleus play in reproduction?

The preoptic nucleus is involved in regulating reproductive behaviors and hormone release related to reproduction.

What does the suprachiasmatic nucleus control?

The suprachiasmatic nucleus is responsible for maintaining the body’s biological clock, regulating circadian rhythms and sleep-wake cycles.

How does the suprachiasmatic nucleus affect reproductive cycles?

The suprachiasmatic nucleus helps regulate reproductive cycles through its influence on hormonal rhythms that control fertility.

What function does the mammillary nucleus serve?

The mammillary nucleus is involved in long-term memory processes, particularly in the formation and recall of memories.

What are the paired structures in the limbic system?

The paired structures in the limbic system are the two hemispheres of the brain.

What is the function of the loop of fiber tracts in the limbic system?

The loop of fiber tracts in the limbic system connects various brain structures, facilitating communication between them.

What role do feedback loops play in the limbic system?

Feedback loops in the limbic system help regulate emotional responses and cognitive functions by allowing for continuous interaction between different brain regions.