Lecture 9: The Nervous System Flashcards
What is the Nervous System divided into?
CNS and PNS
What is included in the CNS?
The brain and spinal cord
What is the function of the CNS?
- Integrates, processes and coordinates sensory data and motor commands
- Seat of higher intelligence
What is included in the seat of higher functions?
- Intelligence
- Memory
- Learning
- Emotions
What is the function of the Peripheral nervous system?
- Carry sensory information from receptors to CNS (afferent)
* Carry motor commands from the CNS to periphery (efferent)
What are the 3 main parts of the Brain?
- Cerebrum
- Cerebellum
- Brainstem
What are Nuclei?
The bundles of cell bodies of neurons on the CNS
What are Tracts?
The axons of cell bodies in the CNS
What are Ganglia?
Clusters of cell bodies in the PNS
What are the Axons in the PNS known as?
Nerves
What are the two types of nerves in the PNS?
Cranial Nerves and Spinal Nerves
Which nerves originate from the Brainstem?
Cranial Nerves
What are the two division of the Peripheral Nervous system?
Somatic and Autonomic (visceral)
What are the two divisions of the Somatic Nervous System?
Motor and Sensory
What are the two divisions of the Autonomic (visceral) nervous system?
Motor and Sensory
What are the two divisions of the Motor Autonomic Nervous system?
Sympathetic and Parasympathetic
What is the meaning of Somatic?
It innervates the somatic body wall ie. Skin, bones, muscle
What is a Motor Neuron?
Any neuron that synapses with a skeletal muscle
What does the Autonomic nervous system control?
Organs
What nerves are part of the PNS?
- Cranial Nerves
- Spinal Nerves
- Peripheral Ganglia
What are Neurons?
Nerve cells that conduct signals
What are Neuroglia?
Support cells for neurons
How many neurons are there in the brain?
100 Billion
How do neurons form connections to other cells?
Via Synapses
Describe the axon of a neuron?
An extension of the cytoplasm with filaments so it doesn’t bend
What are the protein signals that neurons have?
Synapses
What are the two signals that create synapses?
Electrical and chemical signals
What do Dendrites do?
They receive signals from other neurons
What does the size of the Axon depend on?
The function of the axon
What is a Synapse?
Point of contact of an axon terminal with another cell
How does a Neurotransmitter transmit an impulse?
Via neurotransmitters
How many axons do Sensory Neurons have?
2 Axons
Where are the Cell Bodies of all neurons found?
In the spinal cords
What happens when an action potential reaches the synaptic terminal?
Neurotransmitters are released into the synaptic cleft
What do Neuroglia do for cells?
They support cells for the neurons
What are the Neuroglia in the PNS?
Schwann cells and satellite glial cells
What are the Neuroglia in the CNS?
- Astrocytes
- Oligodendrocytes
- Microglia
- Ependymal cells
Where are Satellite Cells found?
Around the cell body of sensory nerve
What is function of Satellite Cells?
They have a supportive role (regulate neurotransmitters, O2 and CO2)
What is the function of Schwann cells?
They Myelinate peripheral axons (sensory and motor) to protect the electrical signal as it moves down the axon
What is the function of Oligodendrocytes?
- Myelinate CNS axons
* Provide structural framework
What is the function of Microglia?
Remove cell debris, wastes and pathogens by phagocytosis
What is the function of Astrocytes?
- Maintain blood-brain barrier
- Provide structural support
- Regulate ions, nutrients and dissolved gas concentration
- Absorb and recycle neurotransmitters
- Form scar tissue after injury
How many axons do Oligodendrocytes Myelinate?
As many as it can reach
What is the function Ependymal cells?
- Line ventricles of the brain
* Circulate cerebrospinal fluid
What causes Multiple Sclerosis?
The lack of Oligodendrocytes myelinate axons
What is the function of the Meniges?
Cover and protect the CNS
What are the 3 layers of the Meninges?
- Dura Mater
- Arachnoid Mater
- Pia Mater
Where does Cerebrospinal fluid sit in the CNS?
Between the Arachnoid and Pia Mater
What are Sucli?
The groves in the brain
What are Gyri?
The hills in the brain
What is the function of Cerebrum?
- Higher cognitive function
- Language and speech
- Somatic motor function
- Somatic sensory function
- Regulates the emotional aspects of behavior
What is the Frontal lobe associated with?
- Thinking, planning, personality
* Motor Planning
Which cortex does the Frontal lobe contain?
The primary motor cortex
Which cortex does the Parietal lobe contain?
The Primary Somatosensory Cortex lobe
What occurs in the Parietal lobe?
Perception of self in space
What is processed in the occipital lobe?
Vision
What happens in the Temporal lobe?
Learning memory and hearing
What does PreCG mean?
Precentral gyrus (primary motor cortex)
What does PosCG mean?
Postcentral Gyrus (primary sensory cortex)
What is the Motor Homunculus?
The mapping of the parts of the brain dedicated to motor processing
What is the Somatosensory Homunculus?
The mapping of the parts of the brain dedicated to sensory processing
What kind of matter is in the different parts of the brain?
- Outer (Cortex): Grey matter
* Inner (Medulla): White matter
What are the 3 types of Fibre Tracts in the Brain?
- Association fibres
- Commissural fibres
- Projection fibres
What kind of connections do Association fibres form?
Intrahemispheric connections
What kind of connections do Commissural fibres form?
Interhemispheric connections
What kind of connections do Projection fibres form?
To and from the cortex connections
What do Short Association fibres connect?
Short Association fibres
What do Long Association fibres connect?
Cerebral lobes in the same hemisphere
How does the Cerebellum act as a Comparator?
It compares intended movement with evolving movement and corrects for errors
Which part of the brain ensures movements are smooth, coordinated and purposeful (skilled)?
The cerebellum
Which part of the brain regulates posture and balance?
The Cerebellum
What are the parts of the Brainstem?
- Midbrain
- Pons
- Medulla
What does the Midbrain Contain?
Motor and Sensory pathways that connect the cerebral cortex to the brain
Which nuclei does the Brainstem house?
The Cranial nerve nuclei
What is the Reticular activating system important for?
Arousal of cortex and consciousness
Where are centers for regulating swallowing and gag reflex?
In the brainstem
What is found in the Midbrain?
- Substantia Nigra
* Relay centers for visual and auditory pathways
What is the function of the substantia Nigra?
•Regulate motor activity
What happens if the Substantia Nigra undergoes neuronal degradation?
Parkinson’s disease
Which nerves are attached to the midbrain?
•Cranial nerves III and IV
What is the Pons?
A bridge between the Cerebrum and the Cerebellum
Which nerves are attached to the pons?
Cranial nerves V, VI, VII, VIII
What does the Medulla oblongata contain?
Vital cardio-respiratory regulatory centres
Which nerves originate in the medulla oblongata?
Cranial nerves IX, X, XI, XII
What are the Ventricles of the brain called?
Lateral Ventricles
Third Ventricle
Fourth ventricle
Which artery supplies the brain?
The internal carotid artery
What does the Carotid cerebral artery split into?
The middle cerebral artery of and the Anterior cerebral artery
What does the Middle Cerebral Artery supply?
The lateral parts of the brain (all lobes)
What does the Anterior Cerebral Artery supply?
The medial structures of the brain (mostly frontal and parietal lobes)
What does the Posterior Cerebral Artery supply?
The underside of the temporal lobe and the medial parts of the occipital lobe
