[EXAM 2] CNS Flashcards
What cells make up nervous tissue?
Neurons and Glia
What are neurons?
the functional unit of the nervous system
What are glia cells?
non-conducting support cells in contact with neurons
What systems make up the nervous system?
Central nervous system
Peripheral system
What is composed in the CNS?
Brain and spinal cord
What divisions make up the the peripheral nervous system?
Sensory Division–> Visceral Sensory Division/ Somatic sensory division
Motor Division–> Visceral Motor Division–> Sympathetic Division & Parasympathetic division & Enteric Division
–> Somatic Motor Division
What makes up a neuron?
Cell Body (soma, perikaryon) Nissl bodies Dendrites Axon Hillock Axon Myelin Sheath
What is a multipolar neuron?
many dendrites ,one axon
- from CNS to periphery (signal such as muscle to contract)
- integrative-neuron to neuron in CNS, ganglia, or special sense organs
What is a bipolar neuron?
one dendrite, one axon
-special sense organs- often the cells that translate something physical or mechanical into electrical impulse to be sent to the brain
What is a unipolar (pseudounipolar) neuron?
no dendrites, one axon
-Sensory- often found in ganglia ,carries signal from periphery to CNS
What is a anaxonic neuron?
many dendrites, no axon
What are motor neurons?
function: conduct impulses from CNS or ganglia to effector cells (muscles or glands)
Somatic efferent neurons: send voluntary impulses to skeletal muscle
Visceral efferent neurons- send involuntary impulses to smooth muscle Purkinje fibers and glands
What are interneurons?
form a network between sensory and motor neurons
What are sensory neurons?
Function: conduct impulses from the receptors or sense organs to the CNS
Somatic afferent fibers- convey sensations of pain, temperature, touch and pressure from the body surface, as well as pain and proprioception from organs within the body
Visceral afferent fibers- transmit pain impulses and other sensations from internal organs, mucous membranes, glands and blood vessels
What cells are myelinated?
Oligodendrocytes-CNS
Schwann Cell- PNS
What part of the nerve fiber do signals use to “skip” along the nerve fiber?
Node of Ranvier
Are Schwann cells myelinated?
Yes and they have extended cytoplasm
What are the two main demyelinated diseases talked about in lecture 1?
Multiple Sclerosis (Oligodendrocytes are having their myelin attacked by immune system) Guillain-Barre syndrome (Schwann cells are having their myelin attacked by immune system)
What is the order from smallest to largest of peripheral nervous tissue/connective tissue covering?
axon+myelin —> nerve fiber —> endonerium –> nerve fascicle –>perineurium–> epinerium –> nerve
Describe the difference between a chemical synapse and electrical synapse
differ morphologically and by mechanism
Chemical synapse
- Vesicles contain neurotransmitters stored in the axon terminal
- released when electrical impulse reaches the axon terminal
- bind to receptors on effector cell
- has a neural junction
Electrical synapse
-use gap junction channel and coupling potentials
What is a nucleus?
a group of neuron cell bodies in the CNS
What is a tract?
a group of nerve fibers traveling in parallel
What is a nerve fiber?
axon, or axon +myelin sheath
What is gray matter?
Area of gray matter where neuron cell bodies are located
What is white matter?
area of the CNS with no neuron cell bodies
What is the Soma or perikaryon?
neuron cell body (conducting)
What are glial cells?
support cells, nonconducting
What does a myelin stain show?
myelinated axons
What does a silver stain show?
shows nerve fibers and cell bodies
What is the Golgi method?
shows the cell body, axons and dendrites in their entirety
What do Nissl stains show?
shows Nissl substance (show ribosomes and rough ER)
-axon hillocks appear best in Nissl or toluidine blue
What are the four main anatomical sections of the CNS?
Meninges- connective tissue cover of the brain and spinal cord
Brain- anatomy of the brain + main cranial nerves
Spinal cord- main nerves that transmit sensory to the brain and motor to the periphery
Blood supply- main vessels that feed the brain and spinal cord
Describe the layers of the meninges?
Dura mater- tough, outer layer; dense irregular connective tissue
Arachnoid matter- transparent, middle layer; thin, delicate CT lined with simple squamous epithelium
- subarachnoid space- filled with CSF
Pia mater- delicate, inner layer; the thin layer of CT lined with simple squamous epithelium
What are the regions of the spinal cord?
cervical
thoracic
lumbar
sacral
What are the enlargements of the spinal cord?
Cervical-nerves feed upper limb
Lumbosacral-nerves that feed lower limbs
What is the medullary cone?
cone shape terminal portion of the spinal cord found between the L1 and L2
serves to stabilize the spinal cord by connecting the conus to the coccyx via the coccygeal ligament
What is the Cauda equine?
bundle of nerves at the lower end of the spine
What is the function of the spinal cord?
Conduction
- sensory information ascends
- motor commands descend
Neural integration
- processing of information from diverse sources
Locomotion
-central pattern generators coordinate simple repetitive movements
Reflexes
-involuntary stereotyped responses to stimuli
What is the spinal tract?
in the spinal cord
Ascending
-carries sensory information to the brain
Descending
-carries motor information from the brain.
Contralateral
-crosses the midline
Ipsilateral
-does not cross the midlineWhat are the regions of the brain?
Cerebrum
-Cerebral cortex
-Basal ganglia
-limbic system
Brain Stem
-midbrain
- pons
-medulla
Diencephalon
- Thalamus
-Hypothalamus
CerebellumWhat components make up the cerebrum?
cerebral cortex
basal ganglia
limbic system
What makes up the brain stem?
midbrain
pons
medulla
What makes up the diencephalon?
Thalamus
Hypothalamus
What are the major landmarks for the cerebrum?
- Two cerebal hemispheres
- Gyri-folds
- Sulci- grooves
- longitudinal cerebral fissure-big sulcus between hemispheres
What is the cerebellum responsible for?
balance and control fine motor movement
muscle tone
coordination
maintenance of normal posture
What are the layers of the cortex in the cerebellum?
Molecular layer
Purkinje layer
Granular layer
What lobes make up the cerebrum?
Frontal Pariental Occipital Temporal Insula
What are functions of the cerebrum?
control voluntary motor activity receive and store sensory information sensory processing learning and memory language and communication integration and coordination of other nerve activity
What are the layers of the cerebral cortex?
- plexiform layer
- external granular layer
- may contain pyramidal cells
- medium pyramidal cell layer
- internal granular layer
- large pyramidal layer
- polymorphic layer
What makes up the Diencephalon?
Thalamus
-relay and integration
-relay nuclei: motor and sensory information
- association nuclei: connect to the limbic system (awareness, emotion, memory)
Midline nuclei: stress, fear, reward
Hypothalamus-connects the nervous and endocrine system
- connects to the limbic system, brainstem, regulates emotions, autonomic control, thermoregulation
Epithalamus
-dorsal region of the diencephalon containing mainly the pineal gland
What makes up the brainstem?
Midbrain
- cranial nerves III & IV
function: motor control, pain, visual attention, and auditory attention
Pons: cranial nerves V-VII, some of VIII
function: facial sensation and expression, control of chewing, respiration, and sleep
Medulla oblongata: cranial nerves IX, X, XI, and some of VIII
function-respiration, heart rate, blood pressure, etc.
Where cerebral spinal fluid held?
Lateral ventricles
- Interventricular foramen
-choroid plexus
Third Ventricle
- cerebral aqueduct
-choroid plexus
Fourth Ventricle
-choroid plexus
Central CanalWhere is CSF made?
Choroid plexus
What glial cells make up the CNS?
Astrocytes-
Structure: large cells with processes that form networks
Function: provide physical and metabolic support
Oligodendrocytes
Structure: small cells
Function: synthesize and maintain myelin
Microglia
Structure: small cells with small dark elongated nuclei
Function: phagocytic
Ependymal cells
Structure: columnar cells
Function: move fluid, synthesize CSF in brain ventricles
What are the blood-brain barrier components and its function?
endothelial cells
basal lamina
end foot processes of astrocytes
function: protect CNS by restricting the passage of molecules
