Corrections: none needed PSY 215 Lecture 5 Anatomy of the Brain Chapter 4, pages 86-96 Announcements: Reminder: The first midterm is in one week! Everyone is encouraged to start studying (recommend 30/night every night until the midterm). NTCs have been posted, along with slides. Please continue to ask lots of questions for your own benefit. Lecture Notes: PERIPHERAL NERVOUS SYSTEM (PNS) ganglia: group of nerves in the PNS o singular ganglion Somatic Nervous System soma =body o get info from body and bring it in like a map to the body dorsal root ganglia: contain cell bodies of neurons that make up spinal nerves (outside spinal cord) o connect to the back side of spinal cord Written by: {Anna Bailey}, {abailey1@naz.edu} Page 1 of 11
(slide 4: not to scale does not need to be memorized) shows the somatic nerves coming out of the spinal cord shows us that the body is very systematically segmented each body region matches up with a specific nerve or group of nerves o important in cases where nerves have been damaged ex. lack of feeling in a certain place on the body will instruct us to look for nerve damage at the corresponding somatic nerves Autonomic Nervous System auto = autonomic, automatic divided into sympathetic and parasympathetic nervous systems sympathetic: fight-or-flight expends energy o can be thought of as emergency mode o increases heart rate and breathing (get energy and oxygen to muscles), and stops digestion processes (digestion uses energy, and that energy is needed in muscles) o short preganglionic axons parasympathetic: rest and digest o conserves and makes energy o long preganglionic axons synapse in ganglia is near target organs Written by: {Anna Bailey}, {abailey1@naz.edu} Page 2 of 11
(slide 6: not to scale, can be found on pg. 88 of textbook) red lines= sympathetic nervous system blue lines= parasympathetic nervous system note that the parasympathetic ganglia are located at the very top and very bottom of the spinal cord, while the sympathetic ganglia are located in the middle both the sympathetic and the parasympathetic nervous systems attach to all organs, but they work in opposition o *important because we need to be able to react quickly in certain situations (sympathetic), but the body needs to come back down (parasympathetic) because it can t function at that rate all the time Written by: {Anna Bailey}, {abailey1@naz.edu} Page 3 of 11
CENTRAL NERVOUS SYSTEM (CNS) The Spinal Cord (slide 7: represents one segment of the spinal cord, can be found on pg. 86 of textbook) H pattern in image= grey matter o the inside of the spinal cord o made of cell bodies (soma) o contain motor and sensory neurons yellowish surrounding in image= white matter o the outside of the spinal cord o made of axons that are covered in myelin o axon pathways are both ascending and descending o actually looks white dorsal root ganglion (singular): go into dorsal side of spinal cord o carries sensory info damage to the dorsal side of the spinal cord can lead to problems with processing sensory info o bulge in the image is where the bulge of cells is motor nerves: exit ventral side of spinal cord o control movement damage to the ventral side of the spinal cord can cause problems with movement Bell-Magendie law: the entering dorsal roots (axon bundles) carry sensory information, and the exiting ventral roots carry motor information Written by: {Anna Bailey}, {abailey1@naz.edu} Page 4 of 11
(slide 9: actual spinal cord, looking from above, can be found on pg. 87 of textbook) this picture gives us an opportunity to compare an actual segment of the spinal cord to the cartoon picture on the page above The Brain Dorsal Choroid Dorsal Choroid Plexus (slide 10: focus on ventricle system, similar image can be found on pg. 96 of textbook) four ventricles: two lateral, 3 rd at midline, 4 th toward the bottom (all shown in purple) choroid plexus: generates cerebrospinal fluid (CFS) (indicated on the image by black squiggly marks) o CFS: fills the ventricles, flows into the central canal of the spinal cord and into the narrow spaces between the brain and the meninges; cushions brain against mechanical shock from head movement o can test CFS for meningitis by performing a spinal tap and removing some CFS Written by: {Anna Bailey}, {abailey1@naz.edu} Page 5 of 11
o CFS can be removed from the brain and reabsorbed in other places if a person has too much five divisions of a mature vertebrate brain o prosencephalon (forebrain) two subdivisions: 1. telencephalon: cerebrum 2. diencephalon: thalamus and hypothalamus o 3. mesencephalon (midbrain) o rhombencephalon (hindbrain) two subdivisions: 4. metencephalon: pons and cerebellum 5. myelencephalon: medulla o *note root word: encephalon =brain (slide 12: midsagittal view, similar image can be found on pg. 91 of textbook) shows the inside of the right hemisphere of the brain gives a clear view of the five divisions each division is also found in the left hemisphere of the brain underneath the myelencephalon is the spinal cord *remember the order of the m s they go in alphabetical order as they descend: Mes, Met, Mye The Brain Stem composed of: o mesencephalon (midbrain) o rhombencephalon (hindbrain) metencephalon and myelencephalon Written by: {Anna Bailey}, {abailey1@naz.edu} Page 6 of 11
metencephalon Reticular Formation (slide 14 and 16 combined: does not include telencephalon) myelencephalon: important for life-sustaining functions o the reason why hanging works so well is because it causes a vertebrate to cut through the medulla and stop these functions o contains ascending and descending pathways metencephalon o cerebellum: looks like a little brain important for fine motor control (ex. art, jewelry-making, etc.) also handles coordination and balance o pons: contains the reticular formation (orange in the image) reticular formation: ascending and descending nuclei pathways ascending areas attention and arousal, along with sleep and activity cycles descending areas handle motor control also processes some types of pain stimuli Written by: {Anna Bailey}, {abailey1@naz.edu} Page 7 of 11
mesencephalon midbrain (slide 15: dorsal side at an angle, focus is on mesencephalon, on pg. 89 of textbook) The Forebrain o four big bumps superior colliculi visual system two of them (singular = colliculus) inferior colliculi auditory system tectum dorsal side tegmentum ventral side diencephalon: sits on top of brain stem (in humans) and composed of two parts o thalamus dorsal (plural = thalami) sensory relay station (except olfaction) contains several kinds of nuclei involved in learning, memory, and emotions (slide 20: dorsal view, focus on thalamus) dark spot between thalami is 3 rd ventricle massa intermedia: neural bridge connect thalami Written by: {Anna Bailey}, {abailey1@naz.edu} Page 8 of 11
o hypothalamus ventral regulates autonomic nervous system and endocrine system via the pituitary gland important for the Four F s (specific behaviors) fight, flee, feed, reproduction *figure 4.12 on pg. 93 of the textbook shows where the hypothalamus is in relation to the thalamus from a dorsal view telencephalon: major part of the brain (slide 22: real human brain, each # label matches the # label given to the five divisions of the brain on pg. 6, similar image on pg. 93 of textbook) o lower left of the image shows where the slice was made on the brain o outside edge (appears darker) grey matter grey matter makes up the cerebral cortex ( cortex = bark) makes up the outer layer contains some bumps and grooves o inside (appears lighter) white matter glia: oligodendrocytes commissures: white matter pathways connecting the two hemispheres corpus collosum major pathway anterior commissure smaller pathway, but still important; located above hypothalamus o *remember: in the spinal cord, grey matter is on the inside and white matter is on the outside, which is opposite from the telencephalon Written by: {Anna Bailey}, {abailey1@naz.edu} Page 9 of 11
(slide 25: on pg. 91 of textbook) o on image, blue stripes = corpus collosum / blue circle = anterior commissure o surface of the telencephalon: cerebral cortex surface, made of grey matter, bark gyri (singular = gyrus) bumps, what you can see sulci (singular = sulcus) shallow grooves fissures deep grooves *remember: every brain looks slightly different, but everyone has the same general features! Cerebral Cortex Lobes four of them (slide 25: location of the four cerebral cortex lobes) Written by: {Anna Bailey}, {abailey1@naz.edu} Page 10 of 11
For more information: This is the link to a 3D animation of the brain. The video revolves the brain and first points out the anatomy, and then goes around again and identifies which area is responsible for a specific function. Note: there is no sound. http://www.youtube.com/watch?v=hvglfcp3ati This website allows you to look at MRIs. You can choose which way you would like to cut the brain (sagittal/axial/coronal) and it takes you all the way through the brain, from one end to the other. Although its terminology (in Structures of the Brain ) is a little more in-depth than what we have done in class so far, I thought the images were really interesting. http://www.med.wayne.edu/diagradiology/anatomy_modules/brain/brain.html Real-life example: Everyone will face an emergency situation at some point in their lives. During that time, the body will feel a surge of adrenaline, increased heart rate, rapid breathing, and other physical changes. We can explain this by what we have learned about the sympathetic nervous system. Similarly, the physical changes we experience when the emergency situation has passed, such as slower breathing, relaxation, and others, can be explained by the parasympathetic nervous system. Written by: {Anna Bailey}, {abailey1@naz.edu} Page 11 of 11