Textbook Notes (369,074)
Canada (162,369)
Psychology (1,899)
PSY290H5 (64)
Chapter 2

Chapter 2 Textbook Notes - The Anatomy and Evolution of the Nervous System

10 Pages
74 Views

Department
Psychology
Course Code
PSY290H5
Professor
Ayesha Khan

This preview shows pages 1,2 and half of page 3. Sign up to view the full 10 pages of the document.
Description
Notes From Reading CHAPTER 2:T HE ANATOMY AND E VOLUTION OF THE N ERVOUS SYSTEM (PGS .26-59) Anatomical Directions and Planes of Section LO1: Identify the major anatomical directional terms and planes of section - Rostral/ Anterior – A directional term meaning toward the head of a four-legged animal o Example: The head of a dog is rostral to its shoulders - Caudal/ Posterior – A directional term meaning toward the tail of a four-legged animal o Example: dog’s ears are caudal to its nose, and its hips are caudal to its shoulders - Inferior/ Ventral – A directional term meaning toward the belly of a four-legged animal - Superior/ Dorsal – A directional term meaning toward the back of a four-legged animal o Example: dog’s ears are caudal to its nose but rostral to its shoulders - Anatomical directions are different in people as we our stance is two-legged, which puts a 90- degree bend in the neurasix o Neuraxis – An imaginary line that runs the length of the spinal cord to the front of the brain o In four-legged animals, neuraxis forms a straight line running parallel to the ground - For dorsal part of human and animal brains: o Animal’s brain are in line with the dorsal parts of the spinal cord o Dorsal parts in human brain form a 90-degree angle with the dorsal parts of the spinal cord - Midline – An imaginary line diving the body into two equal halves - Ipsilateral – A directional term referring to structures on the same side of the midline o Example: your left arm and left leg are ipsilateral - Contralateral - A directional term referring to structures on opposite sides of the midline o Example: my right arm and left leg are contralateral to each other - Medial – A directional term meaning toward the midline o Example: my heart is medial to my arms - Lateral – A directional term meaning away from the midline o Example: my ears are lateral to my nose - Distal – A directional term meaning farther away from another structure, usually in reference to limbs o My toes are distal relative to my knees, and my shoulder are proximal relative to my elbows - Coronal Section – An anatomical section diving the brain front to back, parallel to the face. Also known as Frontal Section - Sagittal Section – An anatomical section that is parallel to the midline - Midsagittal Section – A sagittal section that divides the brain into two approximately equal halves - Horizontal/ Axial Section – An anatomical section that divides the brain from top to bottom Protecting and Supplying the Nervous System - The skull bones are not fully mature in infants instead the skull bones can overlap each other (which helps the movement through the birth canal) - It takes about 18 months for human skull bones to fuse completely LO2: describe the three layers of the meninges, the circulation of cerebrospinal fluid, and the major sources of blood supply to the brain The Meninges - Meninges – The layers of membranes that cover the central nervous system and the peripheral nerves - Dura Mater – “hard mother” The outermost of the three layers of meninges, found in both the central and peripheral nervous systems - Arachnoid Layer – The middle layer of the meninges covering the central nervous system - Subarachnoid Space – A space filled with cerebrospinal fluid that lies between the arachnoid and pla mater layers of the meninges in the central nervous system - Pia Mater – The innermost of the layers of meninges, found in both the central and peripheral nervous system Notes From Reading CHAPTER 2:T HE ANATOMY AND EVOLUTION OF THE NERVOUS SYSTEM (P GS.26-59) - All three of these layers covers th brain and spinal cord o Only the dura mater and pia mater cover nerves that exit the brain and spinal cord o These nerves are referred to as the peripheral nervous system - Meningitis – An infection of the meninges The Cerebrospinal Fluid - Cerebrospinal Fluid (CSF) – The special plasmalike fluid circulating within the ventricles of the brain, the central canal of the spinal cord, and the subarachnoid space o Is secreted within hollow spaces in the brain - Ventricle – One of four hollow spaces within the brain that contain cerebrospinal fluid - Choroid Plexus – The lining of the ventricles which secretes the cerebrospinal fluid o Converts material from the nearby blood supply into cerebrospinal fluid - CSF essentially floats the brain within the skull o The fluid acts like a cushion to soften the blow to your brain o Neurons respond to appropriate input, not to pressure on the brain - Pressure can cause neurons to fire in maladaptive way o By floating the brain, the cerebrospinal fluid prevents neurons from responding to pressure and providing false information - Central Canal – The small midline channel in the spinal cord that contains cerebrospinal fluid o CSF circulates through the central canal of the spinal cord and four ventricles in the brain: the two lateral ventricles, one in each hemisphere, and the third and fourth ventricles in the brainstem - New CSF is made constantly, with the entire supply being turned over about 3 time/day - The old CSF is reabsorbed into the blood supply at the top of the head - Hydrocephalus can cause mental retardation, as the large quantity of CSF prevents the normal growth of the brain o Can currently be treated by the installation of a shunt to drain off excess fluid o Surgery can be used to repair the obstruction (when you’re an adult) - CSF moves through a completely self-contained and separate circulation system that never has direct contact with the blood supply The Blood Supply - The brain has enormous energy requirements, so its blood supply is generous - Carotid Artery – One of the two major blood vessels that travel up the sides of the neck to supply the brain - Vertebral Artery – One of the important blood vessels that enter the brain from the back of the skull - Once inside the skull, these major arteries branch to form the anterior, middle, and posterior cerebral arteries, which serve most of the brain - The brain is unable to store energy, so any interruption of the blood supply produces damages very quickly o Significant brain damage occurs less than 3 minutes after the stopping of a person’s heart beat (but other structures in the body will be not be affected so quickly) The Central Nervous System - There are two components: the central nervous system and the peripheral nervous system - Central Nervous System (CNS) – The brain and spinal cord o Spinal Cord – A long cylinder of nervous tissue extending from the medulla to the first lumbar vertebra o The tissue of the CNS is encased in bone, and the tissue of the PSN is not o Covered by three layers of membranes o Damage to the CNS is considered permanent - Peripheral Nervous System (PNS) – The nerves exiting the brain and spinal cord that serve sensory and motor functions for the rest of the body Notes From Reading CHAPTER 2:T HE A NATOMY AND EVOLUTION OF THE N ERVOUS S YSTEM (P GS.26-59) o Contains all the nerves that exit the brain and spinal cord, carrying sensory and motor messages to and from the other parts of the body o Contains the somatic and autonomic nervous system (sympathetic and parasympathetic NS) o Covered by only two layers of membranes o Recovery can occur in the PNS if damage occurs The Spinal Cord LO3: Describe the major divisions and functions of the spinal cord - The spinal cord is a long cylinder of nerve tissue that extends from the medulla, the most caudal structure of the brain, down to the first lumbar vertebra - Vertebral Column – The bones of the spinal column that protect and enclose the spinal cord - The spinal cord is shorter than the vertebral column because the cord itself stops gorwing before the bones in the vertebral column do - The spinal nerves exit between the bones of the vertebral column - Cervical Nerve – One of the first eight spinal nerves that serve the area of the head, neck and arms - Thoracic Nerve – One of twelve pairs of spinal nerves that serve the torso - Lumbar Nerve – One of the five spinal nerves serving the lower back and legs o If someone complains about their back, then they have lumbar problems - Sacral Nerve – One of the five spinal nerves that serve the backs of the legs and the genitals - Coccygeal Nerve – The most caudal of the spinal nerves - When viewed in a horizontal section, much of the spinal cord appears white o White Matter – An area of neural tissue primarily made up of myelinated axons  These large bundles or tracts of axons are responsible for carrying infomraiton to and from the brain o Gray Matter – An area of neural tissue primarily made up of cell bodies  In the shape of a gray butterfly or letter H in the center of the cord  Gray because the cell bodies absorb some of the chemicals used to preserve the tissue, which stains them gray  Dorsal Horns – Gray matter in the spinal cord that contains sensory neurons (of the H receive sensory input)  Ventral Horns – Gray matter in the spinal cord that contains motor neurons (participate in either voluntary movement or spinal reflexes) - Patellar Reflex – The knee-jerk reflex; a spinal reflex in which tapping below the knee produces a reflexive contraction of the quadriceps muscle of the tight, causing the foot to kick - Damage to the spinal cord results in loss of sensation (of both the skin and internal organs) and loss of voluntary movement in parts of the body served by nerves located below the damaged area o Some spinal reflexes are usually retained o Muscles can be stimulated, but they are not under voluntary control - Spinal damage is considered permanent, but significant process is being made in repairing the spinal cord o Quadriplegic – all sensation and ability to move the arms, legs and torso are lost o Paraplegic – lumbar-level damage, where the use of the arms and torso is maintained, but sensation and movement in the lower torso and legs are lost o All cases of spinal injury, bladder and bowel functions are no longer under voluntary control The Hindbrain LO4: Identify the major structures and functions of the hindbrain, midbrain and forebrain - The hindbrain is located just above the spinal cord - Early in embryological development, the brain dives into three parts: o Hindbrain – The most caudal division of the brain, including the medulla, pons, and cerebellum o Midbrain – The division of the brain lying between the hindbrain and forebrain Notes From Reading CHAPTER 2:T HE ANATOMY AND EVOLUTION OF THE N ERVOUS S YSTEM (P GS.26-59) o Forebrain – The division of the brain containing the diencephalon and the telencephalon - Brainstem – The lower two thirds of the brain, including the hindbrain and the midbrain - The hindbrain divides into the myelencephalon (medulla) and the metencephalon - Myelencephalon/ Medulla – The most caudal part of the hindbrain o Like the spinal cord, contains large quantities of white matter o The vast majority of all information passing to and from higher structures of the brain must still pass through the medulla o Instead of a butterfly appearance, the medulla contains a number of nuclei – collections of cell bodies that share a function o Damage to the medulla is typically fatal due to its control over these vital functions o Reticular Formation – A collection of brainstem nuclei, located near the midline from the rostral medulla up into the midbrain, that regulate sleep and arousal - Metencephalon – The division of the hindbrain containing the pons and cerebellum o Pons – A structure located in the metencephalon between the medulla and midbrain; part o the brain stem located in the hindbrain o Cerebellum – A structure located in the metencephalon that participates in balance, muscle tone, muscle coordination, some types of learning, and possibly higher cognitive functions in humans o Cochlear Nucleus – A nucleus found in the pons that receives information about sound from the inner ear o Vestibular Nucleus – A group of cell bodies in the pons that receive input about the location and movement of the head from sensory structures in the inner ear o The cochlear nucleus receives information about sound, and the vestibular nucleus receives information about the positions and movement of the head o Vestibular input helps us keep our balance o Raphe Nuclei – Nuclei located in the pons that participate in the regulation of sleep and arousal o Locus Coeruleus – A structure in the pons that participates in arousal o The cerebellum contains moer nerve cells (neurons) than the rest of the brain combined o Traditional view of the cerebellum emphasizes its role in coordinating voluntary movements, maintain muscle tone, and regulating balance o Input fro the spinal cord tells the cerebellum about the current locationof the body in 3D space The Midbrain - Mesencephalon – Another term for the midbrain, the division of brain lying between the hindbrain and the forebrain - Tectum – The “roof” or dorsal half, of the midbrain - Tegmentum – The “covering” or ventral half of the midbrain - Cerebral Aqueduct – The small channel running along the midline of the midbrain that connects the third and fourth ventricles - Periaqueductal Gray – Gray matter surrounding the cerebral aqueduct of the midbrain that is believed to play a role in the sensation of pain o Respond to opiate such as morphine and heroine o Electrical stimulation of this area provides considerable relief from pain - Midbrain also contains the most rostral portion of the reticular formation and a number of nuclei associated with cranial nerves - Red Nucleus – A structure located within the reticular formation that communicates motor information between the spinal cord and the cerebellum - Substantia Nigra – Midbrain nuclei that communicate with the basal ganglia of the forebrain o Literally means “black stuff” due to pigmentation of structure o Degeneration of the substantia nigra occurs in Parkinson’s disease, difficulty moving Notes From Reading CHAPTER 2:T HE ANATOMY AND EVOLUTION OF THE NERVOUS SYSTEM (PGS .26-59) - Superior Colliculi – A pair of bumps on the dorsal surface of the midbrain that coordinate visually guided movements and visual reflexes o Receive input fro the optic nerves leaving the eye o Although part of the visual system, colliculli unable to tell you what you’re seeing o Instead, allow us to make visually guided movements and participate in visual reflexes (changing pupil size in response to light) - Inferior Colliculi – A pair of bumps on the dorsal surface of the midbrain that process auditory information o Are one stop along the pathway from the ear to the auditory cortex o Involved with auditory reflexes such as turning the head in the direction of a loud noise o Appear to participate in the localization of sounds in the environment by comparing the timing of the arrival of sounds at the two ear The Forebrain - The forebrain dives again later in embryological development - Dincephalon – A division of the forebrain made up of the hypothalamus and the thalamus o Is located at the rostral end of the brainstem - Telencephalon – The division of the brain comprising the cerebral hemispheres - Cerebral Hemisphere – One of the two large, globular structures that make up the telencephalon of the forebrain - The Thalamus and Hypothalamus o The upper portion of the diencephalon consists of the thalamus o Thalamus – A structure in the diencephalon that processes sensory information, contributes to states of arousal, and participates in learning and memory o The cerebral cortex, forms large numbers of connections with the thalamus o Thalamus is involved with states of arousal and consciousness o Damage to the thalamus typically results in coma, and disturbances in circuits linking the thalamus and cerebral cortex are involved in some seizures o The thalamus has also been implicated in learning and memory o Hypothalamus – A structure found in the diencephalon that participates in the regulation of hunger, thirst, sexual behaviour
More Less
Unlock Document

Only pages 1,2 and half of page 3 are available for preview. Some parts have been intentionally blurred.

Unlock Document
You're Reading a Preview

Unlock to view full version

Unlock Document

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit