Module 5 Flashcards
White Matter of Spinal Cord
Lies outside of grey matter. Consists of tracts of fibres separated into anterior, lateral and posterior funiculi (bundles)
Grey Matter of the Spinal Cord
Inside of the spinal cord. consists of the ventral horn and dorsal horn
Ventral Horn
Carries motor information
Dorsal Horn
Carries sensory information
Between Anterior and Posterior Horn
The lateral horn, which carries information to the sympathetic nervous system
White Matter
Myelinated axons
Grey Matter
Dendrites, neuron cell bodies, glial cells and unmyelinated axons
Pia Matter
Deep to the arachnoid matter is pia matter, which is directly attached to the spinal cord
Arachnoid Mater
Deep to the dura is the arachnoid mater. Between the arachnoid and pia mater is the subarachnoid space, which is continuous with the subarachnoid space in the brain
Dura Mater of SC
Single layer of connective tissue. Between the external surface of the dura mater and the bone is the fat-filled epidural space
Spinal Enlargements
Occur because of the additional nerves exiting the spinal cord that supply the limbs
Where Does Cervical Enlargement supply to
Cervical enlargement supplies innervation to the upper limb
Where does Lumbar Enlargement Supply to
the lower limb
Spinal Cord
Located in the vertebral canal and is supported by the vertebral column. Facilitates communication between the central ns and peripheral ns through the spinal nerves
Cerebral Hemisphere
Two paired hemispheres - right and left, separated by the longitudinal fissure
Cerebral Cortex
Outer layer of the cerebrum
Sulci
Fissures and grooves
Precentral Sulcus
Creates the anterior border of the motor cortex
Central Sulcus
Divides the frontal and parietal lobes, divides the motor from the sensory cortex
Postcentral Sulcus
Posterior border of sensory cortex
Parieto-Occipital Sulcus
Divides the parietal and occipital lobes
Lateral Sulcus
Divides the temporal lobe from the frontal and parietal
Gyri
Lumps and bumps between sulci
Precentral Gyrus (Motor Cortex)
Responsible for sending motor output signals, located anteriorly to central sulcus
4 Lobes of the Cerebrum
- Frontal
- Parietal
- Temporal
- Occipital
Grey Matter - Brain
Never cell bodies, short interneurons and glial cells. Found in the cerebral cortex and the inner areas of the brain
White Matter of the Brain
Bundles of nerve fibres and axons, found in the inner regions of the cerebrum
Corpus Callosum
Connects the two hemispheres of the brain
White Matter Tracts
3 categories of white matter based upon the structures they connect and type of communication they facilitate
Association Fibres
Facilitate communication within one hemisphere
Commissural Fibres
Facilitates communication between the two hemispheres
Projection Fibres
Facilitates communication between different levels of the CNS
Diencephalon of Cerebrum
Central core, surrounded by cerebral hemispheres. It is responsible for sensory and motor relay into and out of the brain and control of the automatic nervous system
Thalamus
Deep brain structure with two bodies, one per hemisphere. Responsible for relaying sensory information, except smell to other areas of the brain
Hypothalamus
Small structure between the thalamus. It is connected to the pituitary gland and controls the release of hormones
Brainstem
Connects the brain to the spinal cord, contains many automatic reflex centres and white matter tracts necessary for human functioning and survival
Midbrain
Anteriorly: large white matter tracts that make up the cerebral peduncles
Postero-Lateral View: Has two pairs of raised bumps, superior and inferior colliculi
Pons
Structure in the middle of the brainstem. Has fibres connecting it to the cerebellum, allowing for communication between the two
Medulla
Continuous with the spinal cord
Cerebellum
Appended to the back of the brainstem, sits under the occipital lobe and functions to coordinate motor activity
Dura Mater - Brain
most superficial and tough - composed of a double layer of connective tissue that attaches firmly to the skull
Longitudinal Fissure
Creating the flax between cerebri between cerebral hemispheres
Transverse Fissure
Between the cerebrum and cerebellum, known as the tentorium cerebelli
Flax Cerebelli
Space at the midline of the cerebellum
Arachnoid Mater - Brain
Loosely covers the brain, creates an area called subarachnoid space which is filled with cerebrospinal (positive) fluid and blood vessels
Pia Mater - Brain
Firmly attached to the cerebral cortex and is the innermost layer of the meninges
Ventricles - Brain
Provide support and protection to the brain, 4 hallow spaces that are continuous with each other and the spinal cord
Lateral Ventricle
Paired C shaped spaces deep within the cerebral hemispheres
Third Ventricle
Located in the middle of the diencephalon between the two halves of the thalamus - Connected to the lateral ventricles by the interventricular foramina
Fourth Ventricle
Sits between the pons and medulla and the cerebellum. Connected to the third ventricle by the cerebral aqueduct. Continuous with the central canal of the spinal cord and the subarachnoid space
Cerebrospinal Fluid
Specialized fluid that bathes the structures of the CNS, it is produced inside the ventricles, primarily by the choroid process
Main Functions of Cerebrospinal Fluid
- Providing a buoyancy effect to the brain and spinal cord
- Provides support and protection to the CNS, acting as a shock absorber
- Serves as a medium for the transport of nutrients, waste, dissolved gases and other substances x
External Topography of Spinal Cord
- Sc begins at the foramen magnum of the occipital bones
- Extends inferiorly to the level of L2 - medullaris
- Inferior to L2 (conus medullaris), the axons emerging from the spinal cord known as the cauda equina
○ Within, a small strand of pia mater, known as the filum terminale, anchors the spinal cord to the sacrum and coccyx
Two Principal Cell Types in the Nervous System
- Neurons
- Supporting Cells
Neurons
Excitable, and can generate and transmit rapid electrical signals to communicate with other neurons
Neuron Structure
- Body
- Cytoplasmic Processes (dendrites and axons)
Body
Houses the nucleus and organelles, transfers electrical signals from the dendrites to the axon
Dendrites
Receive the neuronal signal from other neurons and transfer those signals to the cell body
Axon
Carry the signal from the cell body to the axon terminals, where the signal is transferred to other neurons or organs
Direction of a Nerve Impulse
Allow organs to communicate with one another through rapid transduction of electrical signals known as nerve impulse.
A nerve impulse is unidirectional
Signals travel from dendrites to cell body through the axon to reach dendrites of adjacent neurons or target organs
Classification of Neurons
Based on the number of cellular processes (dendrites and axon) that extend from the cell body
Pseudo Unipolar
One cellular process that splits into a dendrite and an axon
Bipolar
One dendrite and one axon, two cellular processes
Multipolar
Multiple dendrites and one axon, three or more cellular processes
Supporting Cells
Neuroglia or Glia, function to protect and support neurons. they aid in sending signals between neurons to improve communication
4 Types of Supporting Cells
- Astrocytes
- Microglia
- Oligodendrocytes
- Ependymal
Astrocytes
large star shaped cells that communicate with neurons and blood vessels to maintain the integrity of the neural tissue, the most abundant type
Microglia
Able to phagocytose or engulf and destroy pathogens and eliminate waste products from other cells
Ependymal
Cubical in shape and lines cavities of the brain and spinal cord, it assists in production, circulation and monitoring of cerebrospinal fluid
Oligodendrocytes
Wraps around axons in the CBS to form myelin sheath
Myelination
wraps myelin around parts of the axon, insulates the axon and increases the speed electrical signals can travel down
Schwann Cells
Main type of neuroglial cell, equivalent to oligodendrocytes as they form myelin sheath around nerve fibres, but they can only myelinate a portion of one axon
