Summer BI232 Brain HW 2023

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Portland Community College *

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Feb 20, 2024

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Bi 232 Chapter 14 Brain Homework Please read the syllabus and then study the Brain slides and chapter 14 in your text. You may submit your answers in the D2L Assignment Box or in person. If you do your homework online, it is really helpful if you differentiate your writing from the questions: using a color for your text, or bold print, italics, a different font, highlighting - anything to make the questions and answers look different from each other. Thank you. 1. Write and spell correctly the full name of your instructor below. Karen Toyooka 2. Did you read the syllabus in its entirety? If not, please do so as soon as possible. yes 3. What are the consequences for cheating in this course? result in disciplinary actions including but not limited to receiving a failing grade 4. Will I lecture about everything for which you will be tested? Rather than teaching every single fact, you show us directions. 5. When is the last possible drop date for this course this term? July 4, 2023. 6. Looking at the image on slide 3, what general trend do you notice with regards to the degree of folding of the brain neural tissue between the various organisms depicted? What effect (think in terms of a physical property) does the degree of folding have brain processing power, and why? As degree of folding increases, intelligence as well increases. As folding rises, physical properties such as mass also increase. 7. Define the terms rostral and caudal (slide 5) - also from BI 231! Rostral therefore refers to the anterior (front) aspect of the head. Caudal refers to the posterior (back) of the head.

8. Name the three main regions of the brain visible on gross inspection. (slides 5, 6). Your instructor will discuss 6 regions of the adult brain. Brainstem, cerebrum, and cerebellum 9. Describe the following characteristics of the cerebrum: a. Gyrus (plural gyri) – fold on the cerebrum. b. Sulcus (plural sulci) – grooves between the gyrus. c. Hemispheres – the left and right sides of the brain. d. Longitudinal fissure (a space, not technically part of the cerebrum) – a deep groove separating the two hemispheres. 10. Describe these characteristics of the cerebellum: e. Folia – small leaflike laminae of cerebellum. f. Sulcus – a depression or groove. 11. List the three structures of the brainstem. Make sure you can arrange them caudally to rostrally (or vice versa) and be able to label or point them out on a diagram. Mid brain Pons Medulla oblongata 12. Define white matter and describe what parts of neurons, and what specific cellular material, makes up white matter. (slide 7) White matter which is found in the deeper tissues of the brain is made up of nerve fibers that are extensions of nerve cells. 13. Describe where most gray and white matter is found in the cerebrum and cerebellum. In the cerebrum and cerebellum gray is primarily superficial; white matter is found else where.

14. List four ways the delicate brain tissue is protected (slide 8). Meninges which is comprised of three main layers, the strong cranial bones, CSF in the cranial cavity , and brain barrier system all together protect the brain. 15. Name the three primary meninges of the cranial cavity. Which of these meninges has two specific layers? (slide 8) Dura mater has two layers ( perosteal and meningial) Arachnoid mater Pia mater 16. Describe the location of these structures formed by the meningeal layer of the cranial dura mater (consult your text): g. Falx cerebri – invagination into the longitudinal fissure between the cerebral hemispheres. h. Tentorium cerebelli – found at posterior cranial fossa. i. Falx cerebelli – found at occipital bone. 17. Name the three primary dural sinuses formed where the two layers of the cranial dura mater separate. What is found in these sinuses (slide 9)? Superior sagittal sinus, transverse sinus and inferior sagittal sinus. Sinus ontains venous blood.

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18. List the four ventricles of the central cavity of the brain. [Be able to describe their spatial arrangement from rostral to caudal - you may want to practice that]. List the names of the tubes that connect the various ventricles (slide 11). 2 lateral ventricles (1 in each cerebral hemisphere), the third ventricle in the diencephalon, and the fourth ventricle in the hindbrain. The tubes are interventricular foramina and cerebral aqueduct. 19. What is the ‘average’ number of milliliters of CSF that are in circulation? How is the composition of CSF different from blood plasma? (slide 12) It is 100 – 160 ml. compared to plasma it has more sodium and chloride, Less potassium, calcium, and protein. 20. List five functions of CSF.  Increases brain buoyancy  Absorbs shock  Transports gases, wastes, and nutrients  Maintains appropriate environment for action potentials  Helps brain to thermo regulate 21. What structure, found in each ventricle, is responsible for creating cerebral spinal fluid (CSF) there? What is this structure composed of (types of cells, tissues)? (slide 13) choroid plexus which is network of blood vessels. 22. Describe, step by step, the process of CSF circulation. (slide 13/14) Be sure to properly name any structure which CSF passes through.

CSF flows through inter ventricular foramina to 3 rd ventricle then choroid plexus in 3 rd ventricle adds more csf. The CSF flows to the 4 th ventricle through cerebral aqueduct followed by flowing to lateral ventricle. finally, it fills the subarachnoid space where it is reabsorbed into venous blood. 23. Name the major blood vessels (arteries and veins) delivering oxygenated blood to the brain and draining the brain of deoxygenated blood. (slide 16) Internal carotid artery and internal jugular vein. 24. Describe the protective function of the cerebral arterial circle (of Willis). It allows for alternate routes of flow in case there is a blockage. 25. What types of substances pass easily across the blood-brain barrier (BBB) (slide 17)? Glucose, water, O 2 , CO 2 , alcohol, nicotine, caffeine, and anesthetics cross easily. 26. What cells and cellular structures make up the blood-brain barrier? What cells and cellular structures make up the blood-CSF barrier? (slide 17/18). What types of substances cannot cross these barriers easily?. BBB is made of astrocytes; blood CSF barrier is made of ependymal cells. Bacteria, viruses, antibiotics, and cancer drugs have a hard time crossing. 27. What are the circumventricular organs (CVOs), and what functions do they serve (slide 19)? [Your instructor will refer to them as “leaky spots”]. Memorize the two in bold print. They are small collections of tissue surrounding third and fourth ventricles. They increase permeability of BBB and have homeostatic function as well. 28. Describe the location of the diencephalon with relation to the brainstem (image on slide 20). It is found superior to the brainstem. 29. How many pairs of cranial nerves are there, and how many of them arise from the brainstem? Contains 10 of the 12 pairs of nuclei for of cranial nerves.

30. Name the tracts located in the pyramids of the medulla oblongata. Describe the type of information that travels through these pyramidal tracts. (slide 21) Corticospinal tracts – which carries motor signals from the primary motor cortex in the brain, down the spinal cord. 31. Define the decussation of the pyramids. It is the crossing of the fibers of the corticospinal tracts. 32. Describe where the gracile and cuneate fasciculi are in the medulla and list their specific functions. Do fibers traveling through these structures decussate, and if so, where do they do this? (slide 22) Appear as two pairs of ridges on the medulla; gracille medially and cuneate laterally. First order neurons decussate in this fascicule. gracile fasciculus carries sensory input from vertebral level T6 and below; The cuneate fasciculus carries information from T6 and above. 33. How would a stroke on the left side of the brain affect sensory and motor function throughout the body? It affects sensation and motor activity of the opposite side of the body. 34. In general, what is the function of the medulla oblongata? What are some specific functions of this structure? (slide 23) Medulla also serves as the body’s life support system such as heart rate, blood vessel diameter, and respiratory rate via the ANS 35. What is the function of the inferior olivary nuclei? Relay stations between brain/spinal cord, and cerebellum 36. What is the function of the cochlear nuclei, and with what cranial nerve pair are they associated? (slide 24)

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Associated with hearing and the nerve is cochlear branch of vestibulocochlear nerve (VIII) 37. List the four cranial nerves that either start or stop at the medulla (name and Roman numeral). The glossopharyngeal, (IX), vagus (X), accessory (XI), and hypoglossal (XII) nerves 38. Describe the three pairs of cerebellar peduncles. For each pair, describe which brainstem structure communicates with the cerebellum via these tracts. (slide 25) peduncles: -middle- connect cerebellum to pons -inferior- medulla and cerebellum -superior- connect midbrain and cerebellum 39. List the six nuclei housed in the pons (slides 25, 26). Which belong to cranial nerves? Contains nuclei of trigeminal (V), abducens (VI), Facial (VII), vestibulocochlear (VIII) nerves Respiratory nuclei Vestibular nucleus 40. What is the major anatomical feature of the ventral (anterior) midbrain? [Or what do you see?] (slide 27) It contains ontains tracts called cerebral peduncles 41. List the components of the corpora quadrigemina and describe the function of these nuclei (slide 28). Composed of two pairs of sensory nuclei. Coordinate head and eye movements when we visually track an object, allow to blink, relay auditory sensory info to thalamus. 42. What cranial nerve pairs are associated with the midbrain? (slide 29) Nuclei for oculomotor (III) and trochlear nerves (IV);

43. What are the functions of the red nuclei and substantia nigra of the midbrain? Which of these nuclei are implicated in Parkinson’s Disease? What change in this structure occurs in Parkinson’s Disease, and what are the effects of this change (symptom?) (slide 29) Red nucleus helps to smooth out fine motor movements; Substantia nigra prevents unwanted muscle contractions. Substantia nigra is implicated in Parkinson’s disease in which it degenerates. It is characterized by unwanted muscle movement. 44. Describe the reticular formation in one or two sentences (hint: what does reticular mean?) In what brain regions can you find components of the reticular formation in the diagram? (slide 30) a diffuse network of nerve pathways projecting from the brainstem to the spinal cord, cerebrum, and cerebellum, and mediating the overall level of consciousness. Located in Medulla, pons, midbrain, and hypothalamus. 45. Describe the function of the RAS (slide 31). Play role in wakefulness and alertness Release orexin, 46. What types of stimuli affect the RAS, and which do not? Position of head and limbs, visual and auditory cues, pain, pressure, touch, and mental activities but not olfaction. 47. What anatomical structures/specializations allow the cerebellum to contain half the brain's neurons but remain much smaller than the cerebrum? (slide 33) Folia 48. The cerebellum receives information from which four major structures? (slide 34) Inferior cerebellar peduncles Middle cerebellar peduncles Purkinje cells Deep nuclei of cerebellum

49. The cerebellum sends outgoing signals to which two structures (destinations)? (slide 35) Skeletal muscles Motor association area 50. Describe (not just list) several functions of the cerebellum. (slide 36) Receives proprioceptive, visual, and equilibrium sensory information Provides blueprint for movement to motor areas Results in smooth and coordinated skeletal muscle movements, along with proper posture and balance Some spatial perception of 3D objects and interpreting textures of objects by feel alone 51. Name the three components of the diencephalon. Which of the three components is the largest? (slide 37) Thalamus(largest), hypothalamus, and epithalamus 52. Describe the functions of the thalamus. Relay station primarily for almost all general and special sensory info travelling to cerebral cortex, filters sensory information, memory and emotions 53. List several functions of the hypothalamus. (slide 40) Maintains homeostasis of almost all body systems Produces two important hormones that get stored in posterior pituitary Monitoring of body temperature and activation of physiological mechanisms for thermoregulation 54. For each of the following hypothalamic nuclei, using your text, briefly describe their main function. a. Anterior nucleus – support spatial learning and memory. b. Arcuate nucleus – integrates circulating signals of hunger and satiety

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c. Paraventricular nucleus – plays essential roles in controlling stress, metabolism, growth, reproduction, immune, and other more traditional autonomic functions d. Preoptic nucleus – involved in cardiovascular regulation, including the release of atrial natriuretic peptide by the heart in response to high blood volume. e. Suprachiasmatic nucleus – the central pacemaker of the circadian timing system f. Supraoptic nucleus – produce and secrete the peptide hormone vasopressin, also known as antidiuretic hormone (ADH) and oxytocin. 55. List the three major sulci that separate the lobes of the cerebrum, and describe which lobes they separate. (slide 42) A central sulcus separates the frontal and parietal lobes. Lateral sulcus separates each temporal lobe from the parietal and frontal lobes Parieto-occipital sulcus separates each parietal lobe from its neighboring occipital lobe 56. List some of the functions of the individual lobes of the cerebrum. (slides 42-44) Frontal lobe functions in voluntary movement, memory, planning, emotion, mood, social judgment, and aggression Parietal lobe functions in perception of general sensation Occipital lobe functions in vision perception and visual association Temporal lobe functions in hearing, olfaction, language, 57. Describe the three types of tracts found in the brain, including which parts of the CNS they communicate between. Your instructor will describe two types of association tracts. (slide 46) Commissural tracts allow two hemispheres to be linked Association tracts connect different parts of same hemisphere Projection tracts connect cortex to lower CNS centers 58. Name the two main types of cortical neurons found in the cerebrum (slide 47). Multipolar neurons and Stellate cells 59. List three main components of the limbic system and describe two main functions of the limbic system (slide 48).

cingulate gyrus, hippocampus, and amygdale Function: associated with pain, pleasure, affection, anger 60. Describe the functions of the basal nuclei (slide 50). Initiation and termination of movements Suppressing unwanted movements 61. List the integrative brain functions from the slides. (slide 51) Sleep, cognition (association), memory, sensation, motor control, and language. 62. What is the name of the technique that measures electrical activity of the brain? List several conditions that this technique is used to diagnose. (slide 52) Electroencephalogram (EEG) Used in the cases of brain death, consciousness sleeps studies, tumors, epilepsy, trauma, metabolic problems, and degenerative brain diseases. 63. Describe each of the following brain waves exhibited by humans in terms of amplitude, frequency, and whether they are present while a person is awake. (slides 53, 54) a. alpha waves: fairly low amplitude and frequencies of 8-13 Hz b. beta waves: low amplitude, highest frequency waves c. theta waves: fairly low frequency at 4-7 Hz d. delta waves: slow waves (less than 3.5 Hz) with high amplitude 64. List the two hypothalamic nuclei that, in part, control the circadian rhythm. With which structure, related to arousal, do these nuclei communicate? (slide 55) Suprachiasmatic nucleus and Preoptic nucleus are the hypothalamic nuclei related to circadian rhythm.

65. Recall the type of stimuli that will not arouse a person. Why is it that this one particular stimulus will not arouse someone? [You may need to review slide 31 to answer this] That is olfaction because it doesn’t relay at thalamus. 66. Describe the effects of caffeine and adenosine on sleep. On a molecular level, what are these chemicals doing to induce/inhibit sleep? Caffeine blocks adenosine receptors so inhibits sleep. 67. List the two main categories of sleep, and compare/contrast them (how are they alike, how are they different?) with regard to eye motion, dreaming, brain waves present, and which type of restoration (physical and/or mental) takes place in each phase. (slides 56-58) REM and NREM. REM has eye movement but not NREM; in REM 1 st stage involves alpha wave, 2 nd theta wave, and 4 th delta waves where as in REM beta waves will appear; REM is associated with prolonged period of dreaming. 67. What are two proposed functions of sleep paralysis, and during which specific stage of sleep is the strongest sleep paralysis most likely to occur? (slide 57) Prevent person from acting out dreams, or from falling out of a tree It occurs at REM. 69. What is memory consolidation, and which type of sleep is required for this process to occur? (slide 58) NREM Memory consolidation is the process by which a temporary is transformed into a more stable form. 70. Define cognition and give several examples of processes that fall under this category. (slide 59) A processes by which we gain we gain and utilize knowledge. For example: Judgment, reasoning, personality, sensory perception, thinking, memory, and imagination.

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71. Describe the accident that Phineas Gage was involved in and describe how the accident affected him (slide 60). (Your instructor will tell you about a different patient outcome). Tamping rod shot through medial aspect of both frontal lobes leading to surgical removal the prefrontal cortex. Finally, resulting in changes in personality. 72. List three specific brain structures that are involved in memory, and for each structure describe the type(s) of memories in which these brain structures are involved. (slide 62) Association areas of cerebral cortex for sensory/motor/higher order function Hippocampus of limbic system for long-term memory Amygdala of limbic system for emotional memories 73. In general, where are sensory areas located on the cerebral cortex? Where are motor areas located? (slide 63) Sensory areas are posterior half of cerebrum where as motor areas are at anterior cerebrum 74. Where is the primary somatosensory cortex located? What is the function of this area? (slide 64) Posterior to the central sulcus. Receives general sensory information such as pain, pressure, touch, vibration, and temperature 75. Look at the sensory homunculus (slide 65). Why is it that certain body parts appear larger than others? Because some have more sensory receptors than others.

76. Where is the somatosensory association area located? What is the function of this area of the cerebral cortex? (slide 66) 77. For each of the special senses, describe the location on the cerebral cortex where that information arrives. (slides 67-70) a. Vision- b. Hearing- c. Gustation (taste) - d. Olfaction (smell)- e. Equilibrium - parietoinsular vestibular cortex (not on your slides) Saladin figure 16.22. 78. Describe the function of the visual association areas (slide 67). Give a specific example from today of how you used this portion of your brain. [I will check this question] 79. Describe the function of the auditory association area (slide 68) and give a specific example from today of how you used this portion of your brain. [I check this one, too] 80. Where is the motor association area located? What is the function of this area? (Slide 71)

81. Where is the primary motor area located? What is the function of this area? (slide 72) 82. Look at the motor homunculus. Why is it that certain body parts appear larger than others when viewing the homunculus? (slide 73) 83. What is the relationship between numbers of motor units and the degree of fine motor control a body part has? 84. What is the relationship between the size of a motor unit (number of muscle fibers controlled by one neuron) and the degree of fine motor control a body part has? 85. For each of the following language centers, describe specifically where they are located, including which hemisphere they are usually located, and their functions. (slides 74, 75) a. Wernicke’s area- b. Area opposite Wernicke’s- c. Broca’s area- d. Affective language area- 86. List the two components of the central nervous system (CNS), and at least 5 components of the peripheral nervous system. (slide 78)

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87. Define both ipsilateral and contralateral. Are the cranial nerves primarily ipsilateral or contralateral? (slide 79) 88. Which two pairs of cranial nerves are not attached to the brain stem? To which brain structures are they attached? (slide 80) 89. List the names, Roman numerals, and basic functions [motor, sensory, or both] for each of the 12 cranial nerve pairs. [Use a mnemonic device if it is helpful for memorization. There are many available beside the one on the slides or in the text - or, make up your own and share with the class.] 90. List the three cranial nerve pairs involved in eye movement. 91. List all the cranial nerve pairs involved in gustation (taste).

For an exam: Be able to write down the following for each cranial nerve pair. a. whether its function is sensory, motor, or both. b. what effectors are served by the nerve if the function is motor. c. where the receptors are located if the function is sensory. d. what effect damage to the nerve would have on the body. e. How a physician would test for damage to the nerve. f. If any of these nerves are subject to diseases we discussed. g. In which part of the brain the nuclei for the nerve pair are found.

Summer BI232 Brain HW 2023

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