Chapter 3: Neuroanatomy Lecture PDF

Chapter 3 NeuroAnatomy © Cengage Learning 2016 © Cengage Learning 2016  Notes on how to watch and listen! First download the lecture to your computer from Canvas Then Click the Slide Show Tab at the top of the presentation...

Chapter 3 NeuroAnatomy © Cengage Learning 2016 © Cengage Learning 2016  Notes on how to watch and listen! First download the lecture to your computer from Canvas Then Click the Slide Show Tab at the top of the presentation Then Under the Slide Show Tab, click From Current Slide The presentation will automatically advance for you after you advance to the next slide in this presentation. © Cengage Learning 2016  Our Journey Thus Far… © Cengage Learning 2016  Now we move to discussing the Major Regions of the Brain! © Cengage Learning 2016  Learning Strategy for this Chapter Because the bulk of this section is basic anatomy and neuroanatomy, you will rely on memorization of pictures. Memorization for different parts of the brain and body (e.g., cranial nerves) (mnemonic devices) © Cengage Learning 2016  A Note: Some of this information will overlap with previous courses, that’s okay. Learning is reinforced from multiple exposure to information! © Cengage Learning 2016  Notable things that you will learn from lecture. What meningitis is and why it is so common amongst college students? How does our brain develop? Why lobotomy sucks as a method for treating mental illness but may be effective for seizures. Whose brain develops first, male or female? Whose brain ages quicker, male or female? © Cengage Learning 2016  Learning Objectives Define the terms used to describe brain anatomy (neuroanatomy) (Module 3.1) Describe the principal functions of certain brain areas (Module 3.1) List the four lobes of the cerebral cortex and their principal functions (Module 3.2) Briefly discuss past methods for assessing relationship between brain and behavior. (Module 3.2) © Cengage Learning 2016  Again, The Human Nervous System In Pictures © Cengage Learning 2016  Learning Objective Apply anatomical terms to the nervous system © Cengage Learning 2016  Anatomical directions for the body Other Helpful tips: Rostral-towards the nose helpful tips: or front Ipsilateral- refers to Caudal-towards the tail structures on same Dorsal- refers to the back side of the body or top of the head) Contralateral-refers Ventral- refers to the front to structures on or towards the belly opposite side of the body Ex. If a particular region of the left cerebral cortex controls movements of the contralateral hand, we mean it controls the right hand. © Cengage Learning 2016  Anatomical directions for the brain © Cengage Learning 2016  Anatomical Terms Referring to Directions Term Definition Dorsal Toward the back, away from the ventral (stomach) side. The top of the brain is considered dorsal because it has that position in four-legged animals. Ventral Toward the stomach, away from the dorsal (back) side Anterior Toward the front end Posterior Toward the rear end Superior Above another part Inferior Below another part Lateral Toward the side, away from the midline Medial Toward the midline, away from the side Proximal Located close (approximate) to the point of origin or attachment Distal Located more distant from the point of origin or attachment Ipsilateral On the same side of the body (eg., two parts on the left or two on the right) Contralateral On the opposite side of the body (one on the left and one on the right) Coronal plane (or frontal plane) A plane that shows brain structures as seen from the front Sagittal plane A plane that shows brain structures as seen from the side Horizontal plane (or transverse plane) A plane that shows brain structures as seen from above © Cengage Learning 2016  3.1 Structure of the Vertebrate Nervous System (Brief Review) Central nervous system (CNS): the brain and the spinal cord Peripheral nervous system (PNS): connects the brain and spinal cord to the rest of the body – Somatic nervous system: part of peripheral nervous system associated with voluntary control of body movements via skeletal muscles – Autonomic nervous system: controls the heart, intestines, and other organs © Cengage Learning 2016  The Autonomic Nervous System Sends and receives messages to regulate the automatic behaviors of the body (heart rate, blood pressure, respiration, digestion, etc.) Divided into two subsystems – The sympathetic nervous system – The parasympathetic nervous system © Cengage Learning 2016  The Sympathetic and Parasympathetic Nervous Systems Relaxes the body Prepares body for physical activity (fight or inhibits many high flight) energy functions © Cengage Learning 2016  The Sympathetic Nervous System A network of nerves that prepares the organs for rigorous activity – Increases heart rate, blood pressure, respiration, etc. (“fight or flight” response) – Composed of ganglia on the left and right of the spinal cord © Cengage Learning 2016  The Parasympathetic Nervous System Facilitates vegetative and nonemergency responses – Decreases functions increased by the sympathetic nervous system – Composed of long preganglion axons extending from the spinal cord and short postganglionic fibers that attach to the organs themselves – Dominant during our relaxed states © Cengage Learning 2016  Neurotransmitters in the ANS Postganglionic axons of the parasympathetic nervous system mainly release acetylcholine as a neurotransmitter The sympathetic nervous system mainly uses norepinephrine (fight or flight response) © Cengage Learning 2016  Take a 5 Minute Break © Cengage Learning 2016 Now we move to the brain!  Meninges Protective sheath (membrane) around the brain and spinal cord 3 Layers of the meninges Dura mater- outer layer, durable thick and tough Arachnoid- middle layer, soft and spongy Pia mater- closely attached to the brain and spinal cord. The smaller blood vessels of the brain and spinal cord are found here. Arachnoid layer looks like a spider web! © Cengage Learning 2016  The Meninges Contain pain receptors – Meningitis—inflammation of the meninges—is painful and can be fatal – Swollen blood vessels in the meninges are one cause of migraine headaches believed to be caused by abnormal brain activity in trigeminal nerve (cranial nerve) releases neuropeptides leading to inflamed meninges. © Cengage Learning 2016  Meningitis. Because you guys live in close quarters (i.e., dorms)! There are three vaccines for meningitis in the US. © Cengage Learning 2016  Quick note on Meningitis: Vaccines help to prevent meningitis, I said treat in the previous slide, but vaccines help to prevent. We treat bacterial meningitis with combinations of steroids and various antibiotics Most people who get mild viral meningitis usually recover completely in 7 to 10 days without treatment. Antiviral medicine may help people with meningitis caused by viruses such as herpesvirus and influenza. © Cengage Learning 2016  The Ventricles Four fluid-filled cavities within the brain’s central canal containing cerebrospinal fluid Cerebrospinal fluid (CSF): a clear fluid found in the brain and spinal cord – Provides “cushioning” for the brain – Reservoir of hormones and nutrition for the brain and spinal cord – CSF made in the choroid plexus in the ventricles of the brain © Cengage Learning 2016  Hydrocephalus “Water-Head” Condition characterized by blocked CSF flow (e.g., brain tumor, maladaptive cerebral aqueduct). Results in enlarged ventricles due to increased pressure. Walls of ventricles expand producing a condition known as obstructive hydrocephalus. If condition is not reversed can result in permanent, perhaps fatal brain damage. © Cengage Learning 2016  Quick overview of early brain development In the recording, I said the brain is 3.5 grams, but then said 3.5 pounds, the brain is © Cengage Learning 2016 3.5 pounds! 3 Major Divisions of the Vertebrate Brain Learning Objective: Identify the structures and functions of the hindbrain Major Division Ventricle Subdivision Principal Structures Cerebral cortex Lateral Telencephalon Basal ganglia Forebrain Limbic system Thalamus Third Diencephalon Hypothalamus Midbrain Cerebral aqueduct Mesencephalon Tectum Tegmentum Cerebellum Fourth Metencephalon Hindbrain Pons Myelencephalon Medulla oblongata © Cengage Learning 2016  We will start from the back of the brain and work our way to the front! So basically, we will move from the hindbrain and end with the forebrain  The Hindbrain Consists of the: – Medulla oblongata – Pons – Cerebellum Located at the posterior portion of the brain © Cengage Learning 2016  The Hindbrain – The Medulla and the Cranial Nerves The medulla oblongata – Located just above the spinal cord; like an enlarged extension of the spinal cord – Responsible for vital reflexes such as breathing, heart rate, vomiting, salivation, coughing and sneezing The cranial nerves (discuss shortly) – Allow the medulla to control sensations from the head, muscle movements in the head, and many parasympathetic outputs © Cengage Learning 2016  Impact of Opioids and Cocaine Opiates and cocaine have profound effects on medulla nuclei when taken at high doses (“overdose”). Damage to medulla is often fatal because of its prominent role in breathing and heart rate. © Cengage Learning 2016  Cranial nerves (12 pairs) Cranial nerves: Emerge directly from the brain Relay information between the brain and parts of the body, primarily to and from head and neck Each cranial nerve is paired and is present on both sides of the brain. The numbering of the cranial nerves is based on the order in which they emerge from the brain, front to back (brainstem). © Cengage Learning 2016  Cranial nerves (12 pairs) One mnemonic device: 3 O’s (Olfactory, Optic, Oculomotor) 2 T’s (Trochlear, Trigeminal) A (Abducens) Face (Facial) A (Auditory) Vestibulocochlear Gut (Glossopharyngeal) Vagus So (Spinal Accessory) High (Hypoglossal) © Cengage Learning 2016  Memorize The Cranial Nerves and Associated Functions Number and Name Major Functions I. Olfactory Smell II. Optic Vision III. Oculomotor Control of eye movements; pupil constriction IV. Trochlear Control of eye movements V. Trigeminal Skin sensations from most of the face; control of jaw muscles for chewing and swallowing VI. Abducens Control of eye movements VII. Facial Taste from the anterior two thirds of the tongue; control of facial expressions, crying, salivation, and dilation of the head’s blood vessels VIII. Auditory Hearing; equilibrium (Statoacoustic) IX. Glossopharyngeal Taste and other sensations from throat and posterior third of the tongue; control of swallowing, salivation, throat movements during speech X. Vagus Sensations from neck and thorax; control of throat, esophagus, and larynx parasympathetic nerves to stomach, intestines, and other organs XI. Accessory Control of neck and shoulder movements XII. Hypoglossal Control of muscles of the tongue Cranial nerves III. IV. and VI are coded in red to highlight their similarity: control of eye movements. Cranial nerves VII, IX, and XII are coded in green to their similarity: taste and control of tongue and throat movements. Cranial nerve VII has other important functions as well. Nerve X (not highlighted) also contributes to throat movements, although it is primarily known for other functions. © Cengage Learning 2016  There are a ton of videos online that can help you memorize the cranial nerves! © Cengage Learning 2016  Break © Cengage Learning 2016  The Hindbrain – The Pons Lies on each side of the medulla (ventral and anterior) The term pons is Latin for “bridge” – Important for breathing, communication between different parts of brain, sleep, arousal © Cengage Learning 2016  Take home message about Brainstem! Remember, the brainstem consists of the midbrain, pons, and medulla © Cengage Learning 2016  The Hindbrain – The Cerebellum “Little Brain” Structure located in the hindbrain with many deep folds – Helps regulate motor movement, posture, balance, and coordination – Also important for shifting attention between auditory and visual stimuli © Cengage Learning 2016 3 Major Divisions of the Vertebrate Brain Learning Objective: Identify the structures and functions of the midbrain Major Division Ventricle Subdivision Principal Structures Cerebral cortex Lateral Telencephalon Basal ganglia Forebrain Limbic system Thalamus Third Diencephalon Hypothalamus Midbrain Cerebral aqueduct Mesencephalon Tectum Tegmentum Cerebellum Fourth Metencephalon Hindbrain Pons Myelencephalon Medulla oblongata © Cengage Learning 2016 The Midbrain Mesencephalon (midbrain) consists of: Tectum (“roof”) dorsal portion of the midbrain Superior colliculus (processing of visual information and some eye movement) Inferior colliculus (main auditory sound center in the body ) important for signal integration, pitch discrimination etc. Tegmentum (‘covering”) portion below the tectum consists of the following nuclei -Substantia nigra (black substance) -Ventral Tegmental area **Collectively areas that comprise the tegmentum involved in different aspects of motor function (for ex. Loss of DA neurons in Substantia nigra linked to Parkinson’s disease © Cengage Learning 2016  Learning Objective The Forebrain Identify the structures and functions of the forebrain Major Division Ventricle Subdivision Principal Structures Cerebral cortex Lateral Telencephalon Basal ganglia Forebrain Limbic system Thalamus Third Diencephalon Hypothalamus Midbrain Cerebral aqueduct Mesencephalon Tectum Tegmentum Cerebellum Fourth Metencephalon Hindbrain Pons Myelencephalon Medulla oblongata © Cengage Learning 2016  The Forebrain The most anterior and prominent part of the mammalian brain, with two cerebral hemispheres – Consists of the outer cerebral cortex and other subcortical regions (e.g., thalamus, limbic system) – Cortex means “bark” © Cengage Learning 2016  The Cerebrum A.K.A. Cerebral cortex Consists of the cellular layers on the outer surface of the cerebral hemispheres – Divided into two halves – Joined by two bundles of axons called the corpus callosum and the anterior commissure – Each side receives sensory information and controls motor movement from the opposite (contralateral) side of the body © Cengage Learning 2016  Coronal section through cerebrum (Cerebral cortex) Just like spinal cord: White matter- (e.g., anterior commissure) composed of myelinated axons Gray matter- (e.g., cerebral cortex) composed of cell bodies, neurons and glia gives it the gray appearance © Cengage Learning 2016  More on Cerebral Cortex Folding of the cerebral cortex creates gyri and sulci which separate brain regions, increase the brain's surface area, and increase cognitive ability Gyri (gyrus singular) are the folds or bumps in the brain Sulci (sulcus singular) are the indentations or grooves in the brain. Fissures (larger grooves). © Cengage Learning 2016  Lateralization of Cerebral Cortex Some functions are lateralized (located primarily on one side of the brain) © Cengage Learning 2016  Some Senses are not Contralaterally Organized! © Cengage Learning 2016  Corpus Callosum Although the two cerebral hemispheres perform different functions, our perceptions and memories etc. are unified. This unity between hemispheres is accomplished with the corpus callosum (largest white matter tract) © Cengage Learning 2016  Note on Corpus Callosum Emerging evidence suggests that weakened integrity of the callosum contributes to a decline in cognitive function in aging adults. On the flip side, increased callosal thickness in typical childhood development correlates with intelligence, processing speed, and problem-solving abilities. © Cengage Learning 2016  2-minute neuroscience video on Corpus Callosum https://www.youtube.com/watch?v=xMvVAfZcU1s © Cengage Learning 2016  Fun fact on Brains! Male brains are larger in volume relative to female brains (likely due to increased androgen) female volume size There are sex differences in lateralization of brain © Cengage Learning 2016  Fun questions to ask students about developing brain… put this here… Make it flow with previous sections and with disease. © Cengage Learning 2016  Ask the Professor series combine some of this stuff. © Cengage Learning 2016  Several of you guys wanted to learn a bit more about the developing vs the adult brain with various disorders and the connection to neurotransmitters… Here is how some of today’s content can influence this discussion… © Cengage Learning 2016  Fun fact on Brains! On average, the female brain matures and develops faster than the male brain (not anecdotal that girls tend to be more mature than boys) Despite early maturation of female brain, in otherwise, healthy females, the female brain ages slower than healthy male brain All of our brains shrink with age  © Cengage Learning 2016