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Intro to Neuro: Introduction to the Brain - Coggle Diagram
Intro to Neuro: Introduction to the Brain
Orientation of the Brain
Outline the Orientation of the Brain
Orientation of the Brain is based on two axes:
Rostral to Caudal
Rostral to Caudal is the Longitudinal Axis of the Forebrain
Above the axis is the Dorsal Side and Below the axis is the Ventral Side
Brain Centre to Caudal
Brain Centre to caudal is the Longitudinal Axis of the Brainstem and Spinal Cord
Brain Centre to Caudal is based on when an individual or animal is on all fours
Above the axis is the Dorsal Side
Below the Axis is the Ventral Side
Anterior and Posterior
Anterior is in front of
Posterior is behind
Superior and Inferior
Superior is above
Inferior is below
Planes of the Brain
Outline the Planes of the Brain and each view given
Coronal (Frontal) Section
Coronal Section is the cross section of the brain
Coronal Section gives a Medial to Left and Right Lateral view of the Brain
Mid-Sagittal Section
Mid-Sagittal Section separates the two Hemispheres of the Brain
Mid-Sagittal Section gives an Anterior to Posterior View of the Brain
Horizontal Section
Horizontal Section of the Brain gives an Anterior to Posterior View of the Brain and a medial to Left and Right Lateral View of the Brain
Brain lies within a cranial vaults protected by Skull bones, and Cranial Meninges, Cerebrospinal Fluid and Ventricles
Membranes covering the Brain
List the Membranes covering the Brain
Brain is covered by the following membranes:
Dura Mater
Periosteal Dura Mater
Meningeal Dura Mater
Arachnoid Mater
Pia Mater
Lobes of the Brain
List and Label the Lobes of the Brain
Frontal Lobe
Parietal Lobe
Occipital Lobe
Temporal Lobe
Cerebellum
Insular/Limbic Lobe
Outline the function of each Lobe
Frontal Lobe
Frontal Lobe is responsible for high cognitive processing, motor and pre-motor action
Frontal Lobe has the:
Primary Motor and Pre-Motor Cortex
Pre-Frontal Cortex: Broca's Speech Area
Frontal Eye Fields
Motor Association Area
Parietal Lobe
Parietal Lobe is responsible for Somatosensory action such as touch and vibration
Parietal Lobe has the:
Primary Somatosensory Cortex
Wernicke's Area
Sensory Association Area
Wernicke's Area is responsible for speech comprehension
Occipital Lobe
Occipital Lobe is responsible for vision and visual association (Cortical vs Psychic blindness)
Occipital Lobe has the:
Primary Visual Cortex
Visual Association Area
Temporal Lobe which is responsible for Auditory, Speech and Language
Temporal Lobe also has the:
Primary Auditory Cortex
Auditory Association Area
Wernicke's Area
Cerebellum
Cerebellum is responsible for motor co-ordination
Insular/Limbic Lobe
Insular Lobe is associated with tastes vestibular, visceral sensation
Major Divisions of the Brain using embryological terms
Explain the Major Divisions of the Brain using embryological terms
Brain Encephalon
Brain Encephalon is divided into three areas:
Prosencephalon (Forebrain)
Mesencephalon (Mid-Brain)
Rhombencephalon (Hindbrain)
Prosencephalon
Prosencephalon is divided into:
Telencephalon
Telencephalon forms the Cerebral Hemispheres which associated with the Lateral Ventricles
Diencephalon
Diencephalon is associated with the 3rd Ventricle
Mesencephalon
Mesencephalon forms the Mid-Brain which is associated with the Cerebral Aqueduct
Rhombencephalon
Rhombencephalon is divided into:
Metencephalon
Metencephalon forms the Pons and Cerebellum which are associated with the 4th Ventricle
Myelacephalon
Myelacephalon forms the Medulla Oblongata which is associated with the 4th Ventricle
Surface of the Brain
List and Explain the different features of the Brain Surface
Gyrus
Bumps on the brain surface are known as Gyri
Sulcus
Grooves in the brain surface are known as Sulci
Fissures
Deep grooves on the brain surface are known as Fissures
Describe the important different features on the Brain Surface
Central Sulcus
Central Sulcus extends from the Superior most Medial position on the Brain all the way down to the Lateral sides of the Brain
Central Sulcus separates the Frontal Lobe from the Parietal Lobe
Pre-Central Gyrus
Pre-Central Gyrus is located anterior to the Central Sulcus
Pre-Central Gyrus is the Primary Motor Area of the Brain
It is responsible for the control of motor and pre-motor (voluntary) movement
Post-Central Gyrus
Post-Central Gyrus is located posterior to the Central Sulcus
Post-Central Gyrus is known as the Primary Somatosensory area
It is responsible for somatosensory action such as vibration and touch
Lateral (Sylvia) Fissure
Lateral (Sylvian) Fissure is a deep groove which separates the Frontal and Parietal Lobe from the Temporal Lobe
Superior Temporal Gyrus
Superior Temporal Gyrus
Superior Temporal Gyrus is the Primary Auditory Area of the Brain
Superior Temporal Gyrus is responsible for hearing, speech and language
Cingulate Gyrus
Cingulate Gyrus is located above the Corpus Callosum
Cingulate Gyrus is responsible for Limbic Function
Calcarine Sulcus
Calcarine Sulcus separates the Primary Visual Area pf the Occipital Lobe from the other Occipital Areas
Parieto-Occipital Sulcus
Parieto-Occipital Sulcus separates the Parietal Lobe from the Occipital Lobe
Major Sub-divisions of the CNS in Humans
List the major sub-divisions of the CNS in Humans
Cerebral Hemisphere
Cerebral Hemisphere is the folded and highly convoluted area of the Brain
Diencephalon: Thalamus and Hypothalamus
Diencephalon is located below the Cerebral Hemispheres
Cerebellum
Brain Stem:
Midbrain
Pons (Bulge on the Ventral aspect)
Medulla Oblongata (Houses many Autonomic Sensors)
Spinal Cord
Divisions of the Nervous System
Outline the decisions of the Nervous System
Central nervous System
Brain
Spinal Cord
Peripheral Nervous System
Somatic: Involuntary Action
Autonomic: Voluntary Action
Cells in the Central Nervous System
List the Cells of the CNS
Neural Tissue is made up of the following cells:
Neurons
Neurons are the functional units of the CNS
Neurons transfer stimuli between different places
Glial (Support) Cells
Glial Cells serve to support the functioning neurons
Typical Structure of a Neuron
Describe the morphological features of a typical Neuron
A typical Neuron has the following features:
Dendrites
Dendrites are the extensions which receive information
Dendrites transmit the information towards the Cell Body
Cell Body
Axons and Axon Terminals
Axons transmits information away from the Cell Body towards the Muscle
Neurons
Neurons are the individual functional Units
A Group of Neurons is collectively called a Nucleus in the CNS
There are many Nuclei in the Brain
Classification of Neurons
List the classification categories of Neurons
Neurons can be classified according to:
Number of Processes
Function
Mode of Function
The Length of Axons
Describe the classification categories of Neurons
According to the Number of Processes
Unipolar
Bipolar
Pseudo-Unipolar
Multipolar
According to the Function
Sensory (Afferent)
Motor (Efferent)
Interneurons
According to the Mode of Action
Excitatory
Inhibitory
According to the Length of the Axons
Long Axons (Golgi Type 2)
Short Axons (Golgi Type 1)
Afferent (Sensory) Neurons
Afferent Neurons bring impulses to the CNS
Efferent (Motor) Neurons
Efferent neurons carry impulses away from the CNS
Interneurons
Interneurons are located between the Sensory and Motor Neuron
Interneurons are ONLY found in the CNS
Interneurons can be Sensory or Motor in function
The more complex the required action, the more greater the number of interneurons involved
Types of Neurons According to the Number of Processes
Describe the Types of Neurons according to the Number of Processes
Unipolar Neurons
In Unipolar Neurons the Axons and Dendrites move towards the Cell Body
Unipolar neurons are usually found in invertebrates
Bipolar Neuron
In Bipolar Neurons the Cell Body is located between the Axons and Dendrites
Dendrites carry information towards the Cell Body and Axions carry information away from the Cell Body
Bipolar Neurons are found in Cells in the Retinal layer of the Eye
Pseudo-Unipolar Neuron
In Pseudo-Unipolar Neurons the Cell Body sits a distance away from the Axons and Dendrites
Cell body connects to a process, the process then bifurcates and gives rise to the Axon and the Dendrite
Pseudo-Unipolar Neurons are found in the Ganglion Cell of the Dorsal Root
Multipolar Neuron
Multipolar Neurons have many different Dendrites and usually a one single Axon or two Axons
Multipolar neurons are found in the Motor Neuron of the Spinal Cord
Multipolar Neurons are the most common type of Neurons in the Brain
NOTE: Ganglia are a collection of Cell Bodies in the Peripheral Nervous System (PNS)
E.g: Dorsal Root Ganglion
Ganglia vs Nuclei
List the differences between the Ganglia and Nuclei
Ganglia
Ganglia refers to a structure which contains a number of Cell Bodies in the PNS
Ganglia occur in the PNS
Ganglia form Plexuses
Examples of Ganglia: Dorsal Root Ganglia
Nuclei
Nuclei refers to a structure which contains a number of Cell Bodies in the CNS
Nuclei occur in the CNS
Nuclei occurs in Grey matter
Examples of Nuclei: Caudate
Communication between Neurons
Outline the Two Types of Communication between Neurons
Neurons can communicate via two types of communication:
Electrical Communication using Action Potentials
Information is received by the Dendrites
Dendrites then transmit the information to the Cell Body
Cell Body then converts the information into an Action Potential
Then Action Potential is the transmitted by the Axons away from the Cell Body to the Effector
Chemical Communication using Neurotransmitters
Chemical Communication occurs at the end of the Axons
Axons have Neurotransmitters
Neurotransmitter are stored with the Synaptic Vesicles
Arrival of an Action Potential at the Axon stimulates the release of Neurotransmitter into the Synaptic Cleft
Synaptic Cleft is the small space between an Axon and Dendrite/Cell Body
Neurotransmitters are then picked up by the Dendrites
Glial (Support) Cells
Outline the function of the Glial (Support) Cells
Glial (Support) Cells are responsible for the following:
Structural and Metabolic Support
Protection
Guidance of Axonal Growth during development
Role in repair process
Glial Cells of the Nervous System
List the types of Glial Cells of the Nervous System
There are two types of Glial Cells of the Nervous System:
Glial Cells in the CNS
Oligodendrocytes
Astrocytes
Microglia
Ependymal Glia
Glial Cells in the PNS
Schwann Cells (Neurolemmocytes)
Satellite Cells (Non-myelinating Schwann Cells)
Oligodendrocytes
Describe the features and functions of Oligodendrocytes
Oligodendrocytes are responsible for myelinating several segments of the Axon
This results in the formation of the Nodes of Ranvier
Nodes of Ranvier are the segments of the Axon which are unmyelinated
Node of Ranvier contains membrane channel proteins that assist in this process
Nodes of Ranvier increase the speed of Action Potential transmission from the Cell Body through the Axon to the periphery
Astrocytes
Describe the functions of the Astrocytes
Astrocytes are star-shaped Glial Cells
Astrocytes are in contact with Neurons and Capillaries
Astrocytes are the most common Cells int he CNS
Astrocytes are responsible for the following:
Providing structural and trophic support
Regulating the composition of the ECF
Contributing to the Blood-Brain-Barrier
Replace damaged neurons
Provide guidance of axonal growth during development
Microglia
Describe the features and functions of the Microglia Cells
Microglia Cells are derived from the Monocyte lineage
Microglia are the equivalent of the Macrophages in the Nervous System
Microglia are responsible for:
Mediate immune function
Clearing cellular debris
Clearing dead neurons
Ependymal Glial Cells
Describe the features and functions of the Ependymal Glial Cells
Ependymal Glial Cells range in shape from squamous to columnar shaped cells
Ependymal Glial Cells have Cilia
Ependymal Glial Cells are located in the:
Ventricles of the Brain
Central Canal
Spinal Cord
Some Ependymal Glial Cells are specialized and form the Choroid Plexus in the Ventricles
Choroid Plexus produces the Cerebrospinal Fluid (CSF)
Ependymal Glial Cells help circulate the CSF using Cilia
Schwann Cells
Describe the functions of the Schwann Cells
Schwann Cells are found in the PNS
A single Schwann Cell is equal to a single Myelin Sheath segment on the Axon
Schwann Cells have the following functions:
Myelinating several segments of Axons in the PNS
Secreting Neurotrophic Factors
Satellite Cells
Describe the functions of the Satellite Cells
Satellite Cells are non-myelinating Schwann Cells
Satellite Cells surround the Cell Bodies of Neurons in Ganglia (PNS)
Satellite Cells provide support and nutrients
Development of the Nervous System
Outline the Development of the Nervous System
Nervous System develops from the Ectoderm
Ectoderm then forms a Neural Plate and Epidermis
Epidermis is located on either side of the Neural Plate
Epidermis and the Neural Plate are separated by a Neural Plate Border
Neural Plate converges inwards to form a Neural Groove
Neural Plate Borders then become the Neural Folds
Eventually, the Neural Folds join together and separate from the Epidermis
Neural Folds become Neural Crest Cells and the Neural Groove becomes the Neural Tube
Neural Tube becomes the Brain and the Spinal Cord
Neural Crest Cells become the PNS
Grey Matter vs White Matter of the Brain
Differentiate between the Grey Matter and the White Matter of the Brain
Grey Matter of the Brain:
Grey matter of the Brain makes up 40% of the Brain
Grey matter of the Brain contains ALL the Neurons
Grey Matter of the Brain is the place where Neurons receive information and respond
White Matter of the Brain
White Matter makes up 60% of the Brain
White Matter ONLY contains Myelinated and Unmyelinated Axons
White Matter connects different parts of the brain
NOTE: ALL Brains have Grey matter and White matter
Types of White Matter in the Brain
List the Types of White Matter in the Brain
There are 3 Types of White Matter in the Brain:
Commissural Fibres
Association Fibres
Projection Fibres
Describe the Types of White Matter in the Brain
Commissural Fibres
Commissural Fibres allow for inter-hemispheric communication
An example of a Commissural Fibre is the Corpus Callosum
Corpus Callosum allows for inter-hemispheric communication
Association Fibres
Association Fibres allow for intra-hemispheric communication
An example of an Association Fibre is the Cingulum
Cingulum allows for intra-hemispheric communication
Projection Fibres
Projection Fibres connect different parts of the brain
An example of the Projection Fibre is the Internal Capsule
Internal Capsule connects different parts of the Brain
Spinal cord Tracts: Sensory and Motor Pathways
Explain how does communication occur between the Limbs of the Body and the Cerebral Cortex
Spinal Cord houses Spinal Cord Tracts called the Ascending Sensory Tracts and the Descending Motor Tracts
Ascending Sensory Tracts and the Descending Motor Tracts in the CNS decussate (cross over) to various degrees along their course
So that each side of the brain is functionally associated with the contralateral half of the body
This means that if a stimulation occurs on the Right Side of the Body, the stimulation will be processed on the Left Side of the Brain
Peripheral Nervous System
Outline the features of the Peripheral Nervous System
Peripheral Nervous System refers to the Nerves outside the Brain and Spinal Cord
PNS consists of:
Nerve Endings
Peripheral Nerves
Plexuses
Peripheral Ganglia
Describe what structures occur in the PNS
Nerve Endings
Sensory Nerve Endings which detect changes
Motor Nerve Endings which control action and activity
Peripheral Nerves
Peripheral nerves refer to Spinal and Cranial Nerves
Plexuses
Plexuses are structures where spinal and cranial nerves are redistributed
eg: Brachial Plexus
Peripheral Ganglia
Peripheral Ganglia are structures in the PNS outside the CNS that contain a number of cell bodies
eg: Dorsal Root Ganglion
Functional Division of the Peripheral Nervous System: Autonomic Nervous System (ANS)
ANS is responsible for maintaining homeostasis of the internal environment
ANS forms part of the PNS
ANS is divided into:
Parasympathetic Division which performs rest and digest
Sympathetic Division which performs flight or fight
