PGY 451 - EXAM 2 (DR. BAIZER) QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026

PGY 451 - EXAM 2 (DR. BAIZER) QUESTIONS ANSWERED CORRECTLY LATEST UPDATE 2026 What are the two sections of the central nervous system? (1) - Answers -Brain -Spinal cord The building block of the nervous system (1) - Answers Neurons How are different structures formed in the brain? (1) - Answers They are formed from groups of neurons How are the different structures in the brain named? (1) - Answers From early dissections, Latin names were given to represent what they looked like Nuclei (1) - Answers -Groups of neurons -Examples: Lateral geniculate nucleus, visual system, etc. Gray Matter (1) - Answers -Cells/cell bodies -Based on appearance of dissected brain tissue -Cells appear gray White Matter (1) - Answers -Axons -Fibers -Based on appearance of dissected brain tissue Tracts (1) - Answers -Groups of axons interconnecting different parts of the brain Decussate (1) - Answers -When tracts cross from one side of the brain to the other To project (in the brain) (1) - Answers -When neurons from one structure have axons that go to a second structure; the first structure _______ to the second structure. Superior (1) - Answers -toward the top Inferior (1) - Answers -toward the bottom Anterior (1) - Answers -to the front (Rostral) Posterior (1) - Answers -toward the back (Caudal) Medial (1) - Answers -toward the middle Lateral (1) - Answers -toward the sides akak caudal How is the brain normally examined? (1) - Answers -The brain is cut into very thin slices or "sections" How thick are these "sections" of the brain? (1) - Answers -They are typically 5-100 microns (µm) thick -For perspective there are 1,000 µm per mm What do we do with these brain sections? (1) - Answers -Sections are put onto glass slides, stained, and examined under the microscope What are the three standard planes of section that we cut for examination? (1) - Answers -Frontal -Parasagittal -Horizontal What are the 7 major divisions of the CNS? (1) - Answers 7.) Cerebral Hemispheres 6.) Diencephalon 5.) Midbrain 4.) Cerebellum 3.) Pons 2.) Medulla 1.) Spinal Cord How are the cerebral hemispheres divided? (1) - Answers -Cerebral Cortex (outer layers) -Subcortical structures How is the cerebral cortex divided? (1) - Answers -Frontal lobe -Parietal lobe (side) -Occipital lobe (back) -Temporal lobe (towards bottom) Sulci (1) - Answers -Infoldings of the cerebral cortex Gyri (1) - Answers -Surface folds of the cerebral cortex Are the patterns of sulci the same in all brains ? - Answers NO, they are similar but not identical Cytoarchitectonics - Answers how cells differ between brain regions Area 17 - Answers primary visual cortex Area 4 - Answers primary motor cortex Hippocampus (1) - Answers -Used for memory What is the first structure to affected with Alzheimers - Answers Hippocampus basal ganglia - Answers movement and cognition How is the diencephalon divided? (1) - Answers -Thalamus -Hypothalamus Where is the lateral geniculate nucleus located - Answers thalamus What is the function of the cranial nerves? (1) - Answers -To carry information from the head (vision, hearing, olfaction, taste, touch) -Focusing on optic and auditory/vestibular for this lecture 2nd pair of cranial nerves - Answers optic 8th pair of cranial nerves - Answers auditory/vestibular What are the two main divisions of the spinal cord? (1) - Answers -Motor (control of muscles) -Sensory (input from the body) How is the spinal cord protected? (1) - Answers -It is encased in bone for protection The 4 divisions of the spinal cord (1) - Answers -Cervical -Thoracic -Lumbar -Sacral In the spinal chord the axons are located - Answers toward the outside (these are the axons) How is afferent (sensory) information sent to the spinal cord? (1) - Answers -Comes in through the spinal cord dorsally -In other words, it enter the spinal cord through the dorsal root How is efferent (motor) information sent out of the spinal cord? (1) - Answers -Leaves through the spinal cord ventrally -In other words, it leaves the spinal cord through the ventral root How does the shape of gray matter (the ventral root) in cross-sections of spinal cord vary with each level of cord? (1) - Answers -It is dependent on how many spinal motor neurons there are -There are more at levels where there are axons going to big muscles like the ones in the arms and legs -There are fewer at levels where there are axons going to places with less muscle Corpus Callosum (1) - Answers -Axons interconnecting the two cerebral hemispheres What is multiple sclerosis (M.S.)? (1) - Answers -Known now as an autoimmune disorder where the body is attacking the myelin covering the axons What happens to the axons after the myelin is destroyed by the body? (M.S.) What's different about this substance? Does is affect the way we see the images of this disease? (1) - Answers -Once the myelin is gone it is replaced with scar tissue -The density of scar tissue is different than the myelin -Easy to spot this in MRI; can see sclerosis in white spots Neurogenesis (1) - Answers Creation of new neurons. This occurs primarily before birth In what 2 regions does neurogenesis in adults occur - Answers hippocampus (memory) subventricular zone The subventricular zone - Answers source of new neurons in the olfactory system myelination occurs - Answers after birth. This is why motor control is absent at birth. What evidence proves that myelination is not complete after birth? (1) - Answers -Motor control is more or less absent as an infant because the axons are not myelinated -Purpose of motor milestones: Walking, talking, smiling, rolling over The 2 regions in the brain where new neurons are born in adults (1) - Answers -Hippocampus (subcortical structures): critical for memory -Subventricular zone: sense of smell (olfactory system) Different species differ in the - Answers total number of neurons, in brain size (total and regions) Cortex various in Sulci organization of neurons Waht stays the same among different species of brain - Answers All the sub divisions are present Sizes of neurons do not change As complicated behavior shown by a species increases ... (1) - Answers -The surface area of the cerebral cortex increases, causing more sulci and gyri to form because it has to compact more and fold and fit Does the thickness of the cerebral cortex get bigger as behavior gets more complicated for a species? (1) - Answers NO -THICKNESS of the cerebral cortex does NOT change amongst species, the SURFACE AREA DOES How important is vision for primates? (2) - Answers -Very important -50% of the cerebral cortex is devoted to the analysis of visual information -our behavior is visually guided What part of brain analyzes vision - Answers cerebral cortex Cornea (2) - Answers -transparent cover of the front of the eye -where contact lenses sit Sclera (2) - Answers -white cover over the rest of the eyeball -tough connective tissue -continues all around the eyeball Iris (2) - Answers -muscle that contracts or relaxes to control the amount of light entering the eye -controls the diameter and size of the pupil Lens (2) - Answers -located behind the iris -focuses light on the retina Choroid (2) - Answers -layer of blood vessels between the retina and the sclera Retina (2) - Answers -visual neurons (several classes of neurons) reside here -can also be referred to as a "sheet" of neural tissue -considered an outgrowth of the brain because it's connected to it Conjunctiva (2) - Answers -membrane covering the sclera What is conjunctivitis? (2) - Answers -when the conjunctiva gets infected or inflamed -pink eye Retina - Answers Visual neurons Optic nerve (2) - Answers -axons leaving the retina -taking visual signals from the retina into the brain WHAT DOES THE LENS DO - Answers It focuses light onto the retina What happens to the lens as a person ages? (2) - Answers -there is a loss in flexibility -causes difficulty in focusing on close objects What is it called when the lens has a difficulty focusing? (2) - Answers -Presbyopia occurs at age 45 -NEED reading glasses What age-related change happens in the lens at the age of 60+? (2) - Answers -CATARACTS Cataracts (2) - Answers -the lens becomes opaque and cloudy -harder to see -glare at night from headlights, street lamps, etc Is it possible to get rid of cataracts? (2) - Answers Yes -They are easily corrected by surgical removal and replaced with artificial lens (IOL's intraocular lens) How common are cataracts? (2) - Answers -Very common -By age 80, 50% will have cataracts or have had surgery Who develops cataracts? (2) - Answers It is not well understood What are the characteristics of the 3 compartments of the interior of the eyeball? (2) - Answers -fluid filled 1.) to maintain shape as a sphere 2.) to maintain intraocular pressure What are the 3 components of the interior of the eyeball? (2) - Answers -anterior chamber -posterior chamber -posterior cavity What fills the anterior and posterior chambers? (2) - Answers -aqueous humor What fills the posterior cavity? (2) - Answers -vitreous humor Glaucoma (2) - Answers -a condition where there is increased intraocular pressure due to too much fluid -more fluid production or -decrease in fluid drainage What can result from glaucoma? (2) - Answers -increased pressure can result in damage to the optic nerve and loss of vision How can you prevent glaucoma? (2) - Answers -standard check at the ophthalmologist -treated with eyedrops or surgically Visual Field (2) - Answers -all the visual space that we see How is the visual field organized? Be specific (2) - Answers -fixation point (center field) -vertical meridian: splits the left and the right halves of the visual field (90° each side) -horizontal meridian: splits upper and lower halves of the visual field (40° upper field, 60° lower field) Binocular visual field (2) - Answers -part seen by both eyes -extends out to about 60° Monocular visual field (2) - Answers -part seen by each eye individually -part of the far left of the field is seen only by left eye -part of the far right of the field is seen only by right eye Monocular crescents (2) - Answers -seen by the left and right eye INDIVIDUALLY -cover 60°-90° on each side (∼30° each) What is tested for glaucoma - Answers Your visual field Temporal retina (2) - Answers -half of the retina toward the temple or the outside Nasal retina (2) - Answers -half of the retina toward the nose How much information does each half of the brain receive from the visual field? What is it called? (2) - Answers -About half -the CONTRALATERAL half Contralateral (2) - Answers -opposite side Ipsilateral (2) - Answers -same side Which half of the brain sees which side of the visual field? (2) - Answers -right half of the brain sees left side of the visual field -left half of the brain sees right side of the visual field Axons of ganglion cells leave the retina and form ... (2) - Answers ... the optic nerves Two optic nerves join at ... (2) - Answers ... the optic chiasm. This is where they cross Where do the axons from the NASAL retina go after meeting at the optic chiasm? (2) - Answers -they cross the midline and go to the opposite (contralateral) sides Where do the axons from the TEMPORAL retina go after meeting at the optic chiasm? (2) - Answers -they remain ipsilateral Optic Tracts (2) - Answers -the nerves that continue past the optic chiasm Where do the optic tracts go? (2) - Answers -they continue to the thalamus and specifically the lateral geniculate nucleus (LGN) What happens after the visions reach the LGN? (2) - Answers -cells in each LGN send axons to the IPSILATERAL visual cortex What is unusual about the rods, cones, bipolar and horizontal retinal cells? (2) - Answers -these cells do NOT generate action potentials to process information This is due to the lack of axons at this point How is transmitter released in these unusual retinal cells? (2) - Answers -As a function of membrane potential. The NT's are released to ganglion cells which do generate action potential Photoreceptors (2) - Answers -mediate phototransduction -conversion of light energy into energy used by the nervous system How is light energy changed by photoreceptors? (2) - Answers -changed into electrical signals called receptor potentials aka generation potentials What do photoreceptors contain? (2) - Answers -photopigments What happens to the photopigments as light falls on them? (2) - Answers -a conformational change (in their shape)