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FIU Anatomy with Dr.Brinn Exam 3 Latest
2025 /202 6 | Questions and Correct Answers
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Sensory Tract
- carries information to the spinal cord, information is arriving at the spinal cord
- sensory receptors monitor conditions from in/out of body Motor Tract carries information away from spinal cord, information is exiting spinal cord
Sensory and Motor Tract are involved in what? Communication between CNS and PNS through nerves or axons or fibers The sensory Tract ending in cerebral cortex involves how many neurons? 3 neurons The sensory tract ending in cerebellum involves how many neurons? 2 neurons Tracts are paired how along the spinal cord? Bilaterally and Symmetrically Axons within each tract are grouped according to what? The body region that is being supplied with nerves Complexity of Sensory Receptor responses depends on what 2 things? where processing occurs and where motor response is initiated (or where info exits)
The 3 sensory neurons 1st, 2nd, and 3rd order Neurons What % of information that arrives at cerebral cortex passes through the thalamus? 95% Thalamus is responsible for what? distributing information to where it has to go 1st order neuron the neuron that arrives from PNS through dorsal root ganglion (at the level of the spinal cord) to brain stem 2nd Order Neuron the neuron that synapses on the brain stem or spinal cord and goes to the thalamus 3rd Order Neuron the neuron that leaves the thalamus and goes to specific areas of the cerebral cortex (this will give you different sensations, depending on where the thalamus sends it in the brain) Sensory Homoculus shows specific areas of body where you will feel more or less sensation In your cerebral cortex, body parts that are more medial will be located more laterally Neurons in your sensory tract are arranged into 3 anatomical principles
- Sensory Modality Arrangment
- Medial-Lateral Rule
- Somatotopic Arrangement
Motor Commands can be distributed by 2 systems:
- Somatic Nervous System
- Autonomic Nervous System Somatic Nervous System distributes motor commands to skeletal muscle Autonomic Nervous System distributes motor commands to smooth/cardiac muscles, and glands (Viscera or organs) what are the 2 Motor Neurons Upper Motor Neuron and Lower Motor Neuron Upper Motor Neuron Neuron that exits cerebral cortex, goes down through brain stem (information can either leave through the brain stem or goes down to the spinal cord)
- 85% of info that goes down to spinal cord will cross over to the other side and exit through the motor tract
- 15% maintains the same side of the tract and exits through motor tract
- can either excite or inhibit your lower motor neuron Lower Motor Neuron relay motor commands from CNS motor nuclei to skeletal muscle fibers
- synapses at brain stem or spinal cord Motor Homunculus shows how much motor activity the body parts have Motor Tracts that carry SUBCONSCIOUS motor commands
- rubrospinal tract
- reticulospinal tract
- tectospinal tract
- vestibulospinal tract Motor Tracts that carry CONSCIOUS motor commands
- Anterior Corticospinal tract
- Lateral Corticospinal tract Motor information leaves at the anterior part of your brain Sensory Information arrives at the posterior part of your brain Autonomic Nervous System Tracts
- info goes to organs
- motor info leaves through hypothalamus, through base of brain stem, and leaves through the spinal cord What will develop the CNS and what does it form? The neural tube will form the cephalic area and spinal cord. Brain Development in 1st 3 weeks Cephalic area is divided into 3 parts: prosencephalon, mesencephalon, and rhombencephalon What happens to the prosencephalon during brain development in 6 weeks Prosencephalon divides into: Telencephalon (forms the cerebrum) and the Diencephalon What happens to the Mesencephalon during brain development in 6 weeks It will become the mid-brain What happens to the Rhombencephalon during brain development in 6 weeks Rhombencephalon divides into: Metencephalon (give rise to cerebellum and pons) and Myelincephalon (gives rise to medulla oblongata)
Hypothalamus Below thalamus, involved in emotion
- contains structures important for production of different types of hormones
- controls blood pressure, heart rate, lets you know when hungry/thirsty
- forms floor of 3rd Cerebellum
- coordinates somatic motor patterns (helps with walking)
- adjusts output of other somatic motor centers in brain and spinal cord (helps with muscle control)
- controls a lot of motor activities (things you don't think about) Subconscious coordination of movements
- has two hemispheres: right/left that are separated by the vermis Cerebrum
- where cautious thought process occurs
- stores memory, intelligence functions, cautious regulation of skeletal muscular contraction
- has 2 hemispheres: right/left that are separated by the longitudinal fissure The left and right ventricles are separated by what? Septum Pellucidum, no communication btwn them The 3rd and 4th ventricle are separated by what? Aqueduct of the mid-brain Dura Mater
- outermost layer of the brain, surrounds brain and spinal cord
- folds in this layer will form specific structures Interventricular Foramen Space where right/left lateral ventricle release contents into 3rd
- how 3rd connects to lateral ventricles In your blood-brain barrier, what covers blood vessels? Why? Endothelial Cells, they have tight junctions so very few things like nutrients, oxygen, and waste products can go through In your choroid plexus, endothelial cells with have spaces called what? Why? Fenestrated Capillaries, these spaces allow more influx/eflux of nutrients and waste products in choroid process Epindymal Cells Infundibulum
connects hypothalamus to pituitary gland The medullary body is located where? Posterior wall of hypothalamus 3 layers of the cerebellum Mollecular, perkinje, and granuole cell layer Mollecular Layer outer layer of the cerebellum, contains dendrites of the purkinje cells Purkinje Layer middle layer of the cerebellum, contains purkinje cell body Granuole Cell Layer most internal layer of cerebellum, contains granuole cells and axons of purkinje cells Central Sulcus divides cerebrum hemispheres into anterior and posterior
- divides motor from sensory info. Lateral Sulcus divides the frontal lobe from the temporal lobe Occipital Sulcus divides occipital lobe from parietal Primary Motor Cortex information from muscles arrives here first Somatic Motor Association Area Primary motor cortex will send info to this Occipital lobe has what function? visual processing of words (vision) Parietal lobe has what function? spatial coordinates of body and surroundings (naming objects) Wernicke's area function language comprehension intelligence Broca's area function
N V
Trigeminal Nerve (facial innervations) N VI Abducens Nerve (eye movement) N VII Facial Nerve (mixed) N VIII Vestibulocochlear Nerve (Innervates Vestibule and cochlea) N IX Glossopharyngeal (mixed) N X Vagus Nerve (mixed) N XI Accessory Nerve N XII Hypoglossal Nerve (moves tongue) Sensation Sensory info. arriving at CNS Perception conscious awareness of sensation What are your special senses? smell, taste, balance, hearing, vision
- sensations provided by specialized receptor cells What are your general sense? Temperature, pain, touch, pressure, vibration, and proprioception
- sensations arrive at primary sensory cortex Sensory Decoding active sensory neurons will indicate location and nature of stimulus, provides info. about the strength, duration, variation, and movement of stimulus Tonic Receptor
sensory receptor that is always active (slow adapting receptor) Phasic Receptor sensory receptor that is active for a short period of time or "phase"
- provides info. on intensity and rate of change of a stimulus (fast adapting receptor)
- reason why you get used to really cold/hot temp. Adaptation a reduction in sensitivity due to constant stimulus (PNS) Peripheral (sensory) adaptation a reduction in sensitivity due to axons being tired of sending signal (PNS) Central Adaptation CNS adapts to stimulus, you are aware stimulus is happening but brain ignores it because it is not important at the time (CNS) Nociceptors General Sense receptors that sense pain
- ones that are sensitive to temp., mechanical damage, and chemicals
- large receptive fields
- slow, fast, referred pain Thermoreceptors cold and warm receptors located on the dermis of the skin, skeletal muscles, liver, and hypothalamus
- conducted along same pathways that carry pain receptors
- 3x more cold receptors than warm Free Nerve Endings
- receives difference in temp., takes pain info. (thisis why you sometimes feel pain in extreme temp.) Mechanoreceptors
- sensitive to any type of distortion on skin, organs, joints, or muscles (anything that will distort the membrane of the cell)
- tactile, baroreceptors, and proprioceptors Tactile Receptor type of Mechanoreceptor on the skin
- distortion of: pascinion, rufinite corpuscle, merkel cells, or free nerve endings will give you sensation of touch Barroreceptors
tongue->facial nerve->vagus nerve or glossopharyngeal->nucleus solaritus->thalamic nucleus->gustatory cortex How sound comes into the ear sound waves go through external Acoustic meatus->causes tympanic membrane to vibrate->auditory ossicles move->stapes hits oval window->sound waves circulates into cochlea->stimulates basilar membrane->sound goes out round window-> stimulates vestibulocochlear nerve Membranous Labrynth part of Inner ear that contains basilar membrane
- filled with endolymph, surrounded by perilymph inside bony labrynth
- can be divided into:cochlear duct and vestibular complex ----vestibular complex can be divived into Semicircular Ducts (rotation) and utricle and saccule (gravity and linear acceleration) Anterior Semicircular Duct "yes" movement of head Lateral Semicircular Duct "no" movement of head Posterior Semicircular Duct tilting head Otolith in utricle and sacculae: on top of the gelatinous material is statoconia (calcium carbonate crystals) By tilting your head, what moves? statoconia moves, which moves the gelatinous material, which moves hair cells (which then stimulates the nerves) organ of corti is within what structure? cochlea Within the organ of corti are what 2 membranes? tectorial and basilar membrane when the tectorial membrane goes left to right basilar membrane goes right to left kinocilium crushes steriocilia and blocks signal when the tectorial membrane goes right to left basilar membrane goes left to right
steriocilia will tickle kinocilium and activate signal Auditory Sensation Pathway steriocilia stimulates kinocilium->signal tracles through vestibulocochlear nerve->thalamus->different areas of brain for detection of sound Layers of the eye Sciera (outer, white layer) choroid retina (inner most layer) Cornea extension of the sciera Iris made up of muscle that controls the amount of light pupil light goes in through here Ciliary Body continuation of the iris, connect iris to choroid Anterior Cavity of the eye filled with aqueous humor
- contains 2 compartments (posterior and anterior chamber) Posterior Cavity of the Eye filled with vitreous body (thicker) Suspensory Ligaments ligaments that hold the lens
- shapes the lens in order to see things that are close or far away
- as you get older, ligament loses flexibility, disabling you from seeing far or close How light travels through eye cornea->pupil->lens->back of retina->activates nerve->leaves through optic nerve->visual cortex of occipital lobe Optic Disc within your optic nerve, where all of them come together, forms a depression,
- also known as your blind spot (no cones or rods) Central Retina Artery and Vein
