anatomy midterm 4 - lecture 17 - forebrain and cranial nerves

what is the diencephalon?

structure within the brain that is the connection between the brain stem and cerebrum which contains four distinct regions: the thalamus, hypothalamus, epithalamus, and subthalamus

function of the hypothalamus

primary control center for endocrine system and ANS, regulating vital bodily functions like temp, hunger, and hormone release

how many groups of nuclei are in the hypothalamus?

11

what is the pituitary gland?

“master gland” that releases regulatory hormones to control other glands like the thyroid gland, adrenal gland, and gonads

what is the function of the thalamus?

it is a crucial sensory relay station that processes and transmits sensory information to the cerebrum

what is the function of the subthalamus?

it regulates skeletal muscle movements and contains a nucleus that is linked to basal nuclei, playing a role in motor control

what is the function of the epithalamus?

it consists of the habenula, which sends signals to the brainstem to regulate emotional and motivational states, and the pineal gland, which produces melatonin

what signals does the thalamus process?

primarily sensory signals (visual, auditory, and somatosensory), but not olfactory and gustatory

what is the geniculate nucleus?

part of the thalamus that plays a crucial role in processing sensory information, specifically visual and auditory signals

what are the two geniculate nuclei?

lateral and medial geniculate nuclei

what is the function of the lateral geniculate nuclei?

it is primarily responsible for relaying visual information from the retina to the primary visual cortex

what is the function of the medial geniculate nucleus?

it is primary responsible for relaying auditory information from the cochlea to the primary auditory cortex

what is the frontal lobe responsible for?

planning, judgment, decision making, impulse control, social interaction, reasoning, and containing the Broca’s area and primary motor cortex

what is the insula lobe responsible for?

it is associated with empathy and visceral sensation

what is the temporal lobe responsible for?

it processes auditory and olfactory information and holds Wernicke’s area and the hippocampus

what is the occipital lobe responsible for?

it serves as the brains primary visual center

what is the parietal lobe responsible for?

it integrates sensory information from general senses such as pain, temp, touch, pressure, vibration, and proprioception, as well as taste, and also holds the primary somatosensory cortex

what are association areas?

regions of the cerebral cortex that are responsible for integrating and processing information from multiple sensory and motor areas

what are the three types of white matter tracts?

association, commissural, and projection tracts

what are association tracts?

white matter tracts that connect different regions within the same cerebral hemisphere

2 examples of association tracts

cingulum (link different lobes) and subcortical U fibers (connect gyri in a lobe)

what are commissural tracts?

white matter tracts that cross from one hemisphere to the other

2 examples of commissural tracts

corpus callosum and anterior commissure (helps transfer olfactory info between temporal lobes in both hemispheres)

what are projection tracts?

white matter tracts that connect higher brain centers to lower ones, including the spinal cord (can be afferent or efferent)

2 examples of projection tracts

corticospinal tract (controls voluntary muscle movements) and the fornix (efferent pathway of the hippocampus)

what is the corona radiata?

internal capsule of myelinated axons deep within the cerebrum that contains afferent and efferent neurons to transmit signals to and from the cerebral cortex; has nerve fibers organized in a fan like pattern

what are basal nuclei/ganglia? where do they receive input from?

subcortical nuclei responsible for motor control that are lateral to the thalamus; receive input from substantia nigra and motor areas of the cortex

what 3 things does the basal ganglia refer to?

caudate nucleus, putamen, and globus pallidus

what is the corpus striatum?

collective name for the putamen and caudate nucleus

what 2 segments is the globus pallidus divided into?

the internal segment (GPi) and the external segment (GPe)

what is the function of the GPi?

to send inhibitory signals to the thalamus, regulating motor output

what is the function of the GPe?

to modulate the activity of the striatum

what cranial nerves are apart of the CNS?

cranial nerves I and II

what cranial nerve originates from the spinal cord?

cranial nerve XI

what is ipsilateral transmission?

cranial nerves transmitting fibers between the brainstem and receptors or effectors on the same side of the head

what is cranial nerve I and its functions?

olfactory nerve: compromises sensory fibers responsible for the sense of smell

what is cranial nerve II and its functions?

optic nerve: responsible for transmitting visual information from the retina of the eye to the brain and plays a crucial role in vision 

what is cranial nerve III and its functions?

oculomotor nerve: carries somatic motor and parasympathetic fibers and controls eye movements, regulates pupil size, controls lens shape, and elevates the eye

what is cranial nerve IV and its functions?

trochlear nerve: controls the superior oblique muscle, moving the eye downward and rotating inward to allow for binocular vision

what is cranial nerve V and its functions?

trigeminal nerve: primary sensory nerve of the face that carries information about touch, pain, and temp from face to the brain, as well as controls the muscles used for chewing

what is cranial nerve VI and its functions?

abducens nerve: controls lateral rectus muscle of the eye, which abducts the eye for horizontal motion and proper alignment of both eyes

what are the three divisions of the trigeminal nerve?

ophthalmic, maxillary, and mandibular

what is cranial nerve VII and its functions?

facial nerve: motor control of facial expression and stapedius, taste sensation from anterior two thirds of the tongue, and gland control (lacrimal, nasal, and salivary)

what is cranial nerve VIII and its functions?

vestibulocochlear nerve: sensory nerve responsible for hearing and balance, formed by the cochlear and vestibular nerve

what is cranial nerve IX and its functions?

glossopharyngeal nerve: sensory input from posterior third of the tongue, pharynx, and middle ear, controls stylopharyngeal muscle (elevates the pharynx), and stimulates parotid (salivary) gland

what is cranial nerve X and its functions?

vagus nerve: supplies muscles of the pharynx, larynx, and soft palate, which is essential to swallowing and phonation, carries sensory fibers from the pharynx, larynx, and viscera, slows HR, stimulates digestive secretions, etc

what is cranial nerve XI and its functions?

accessory nerve: joins with vagus nerve to supply muscles of larynx and innervates sternocleidomastoid and trapezius muscles

what is cranial nerve XII and its functions?

hypoglossal nerve: motor nerve that controls nearly all movements of the tongue for speech, eating, and swallowing