The Nervous System
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- Created by: Jenp15
- Created on: 03-02-23 10:16
Function of the Nervous System
*Master controlling and communicating system in the body
*Responsible for all behaviour and body homeostasis
*3 overlapping functions:
-Monitors changes (stimuli) inside and outside of the body (sensory input)
-Processes and interprets the input (Integra
*Responsible for all behaviour and body homeostasis
*3 overlapping functions:
-Monitors changes (stimuli) inside and outside of the body (sensory input)
-Processes and interprets the input (Integra
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Components of the nervous system
Divided into two principle parts:
-The Central Nervous system
-The Peripheral Nervous System
-The Central Nervous system
-The Peripheral Nervous System
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Central Nervous System
-Brain
-Spinal Cord
-Integrating 'command' centre
-Interprets incoming info and dictate responses
-Spinal Cord
-Integrating 'command' centre
-Interprets incoming info and dictate responses
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Peripheral Nervous System pt. 1
-Sensory (afferent) division
-Impulses to the CNS from skin, skeletal muscles, joints, organs.
-Keeps CNS informed of what is going on inside and outside of the body.
-Impulses to the CNS from skin, skeletal muscles, joints, organs.
-Keeps CNS informed of what is going on inside and outside of the body.
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Peripheral Nervous System pt. 2
-Motor (efferent) division
-Impulses from the CNS to efferent organs, muscles and glands to bring about a motor response
-Somatic (to skeletal muscles) - voluntary
-Autonomic (to smooth muscles in organs, cardiac muscles and glands)- involuntary
-Impulses from the CNS to efferent organs, muscles and glands to bring about a motor response
-Somatic (to skeletal muscles) - voluntary
-Autonomic (to smooth muscles in organs, cardiac muscles and glands)- involuntary
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Nerve Cells
*Neurones - excitable cells that transmit electrical impulses
-Extreme longevity
-Amitotic
-High metabolic rate
*Most neuron cell bodies are in the CNS (grey matter)
*Collection of them = nuclei
*Fewer in the PNS. collection in PNS= ganglia
-Extreme longevity
-Amitotic
-High metabolic rate
*Most neuron cell bodies are in the CNS (grey matter)
*Collection of them = nuclei
*Fewer in the PNS. collection in PNS= ganglia
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Nerve cells contd.
-Last a lifetime if you look after them (over 100 years)
-Lose their ability to divide once they have specialised, so if they are destroyed, they can not be replaced.
-Require a lot of oxygen and glucose to function properly
-Lose their ability to divide once they have specialised, so if they are destroyed, they can not be replaced.
-Require a lot of oxygen and glucose to function properly
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Dendrites
-Surround branching extensions close to the cell body
-Provide huge surface area for reception of signals from other neurone
-Convey messages towards the cell body
-Provide huge surface area for reception of signals from other neurone
-Convey messages towards the cell body
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Axons
-Each neuron has a single axon
-Some are short, others are long (e.g. Nerve fibre from spine to foot)
-Generate and transmit nerve messages away from the cell body via the axonal terminals
-Impulse in terminal causes secretion of neurotransmitter that f
-Some are short, others are long (e.g. Nerve fibre from spine to foot)
-Generate and transmit nerve messages away from the cell body via the axonal terminals
-Impulse in terminal causes secretion of neurotransmitter that f
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Myelin
-Myelin sheath covers long or large nerve fibres (axons)
-White, fatty sheath called myelin
-Increases speed of transmission
-Formed by Schwann cells in the PNS and oligodendrocytes in CNS
-Forms the 'white matter' in brain and spinal cord. Cell bodies
-White, fatty sheath called myelin
-Increases speed of transmission
-Formed by Schwann cells in the PNS and oligodendrocytes in CNS
-Forms the 'white matter' in brain and spinal cord. Cell bodies
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Synapse
-Information from one neutron flows to another neurone across a synapse
-The synapse is a small gap separating neurones
-The synapse consists of:
*a presynaptic ending that contains neurotransmitters, mitochondria and other cell organelles
*A postsynapt
-The synapse is a small gap separating neurones
-The synapse consists of:
*a presynaptic ending that contains neurotransmitters, mitochondria and other cell organelles
*A postsynapt
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Meninges
-Dura mater- lines cranial vault and vertebral canal; thick, collagen and elastin
-Arachnoid mater - thin membrane separated from dura mater by fluid. Deep to this is the subarachnoid space containing CSF.
-Pia mater- loose membrane of connective tissue;
-Arachnoid mater - thin membrane separated from dura mater by fluid. Deep to this is the subarachnoid space containing CSF.
-Pia mater- loose membrane of connective tissue;
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Cerebrospinal fluid (CSF)
-CSF acts as a shock absorber and supplies nutrients to the brain and spinal cord
-Created and secreted by the choroid plexus (capillaries found in ventricles)
-Created and secreted by the choroid plexus (capillaries found in ventricles)
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Grey Matter
-Cell Bodies and dendrites; form nuclei e.g. Thalamus; also form outer layer of cortex (Sulci and Gyri)
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White Matter
-Axons; core of cerebellum and cerebrum; connecting fibres between areas of the brain e.g. corpus callosum and internal capsule
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Sensory Responses
-Thalamus
-All sensory information (expect smell) passes through the thalamus and radiates out of the cortex
-Internal capsule
-Contains fibres to and from the spinal cord and cortex
-All sensory information (expect smell) passes through the thalamus and radiates out of the cortex
-Internal capsule
-Contains fibres to and from the spinal cord and cortex
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Motor Responses
-Involves motor cortex, basal ganglia, cerebellum, spinal cord and thalamus
-Basal ganglia - at base of cerebral cortex and midbrain
-Relies on sensory cues from the environment to process movement responses
-Info from movement and sensory areas of corte
-Basal ganglia - at base of cerebral cortex and midbrain
-Relies on sensory cues from the environment to process movement responses
-Info from movement and sensory areas of corte
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Motor Response cont.
-Upper motor neurone are in the CNS
-Lower motor neurone originate in the anterior columns of the spinal cord (motor tracts) or the nuclei of the motor cranial nerves
-Lower motor neurone originate in the anterior columns of the spinal cord (motor tracts) or the nuclei of the motor cranial nerves
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Internal control: Hypothalamus
-Lies beneath thalamus
-Homeostasis - maintaining a constant internal environment (temp, hydration, etc.)
-Sends output to autonomic Nervous system
-Homeostasis - maintaining a constant internal environment (temp, hydration, etc.)
-Sends output to autonomic Nervous system
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Internal Control: Limbic system
- complex series of interconnected structures in forebrain and midbrain
-Controls:
*Emotion and motivation, esp survival related
*Retention of recent memory
*Coordination of movement
*Emotional aspects of movement (e.g. physical anger response)
-Controls:
*Emotion and motivation, esp survival related
*Retention of recent memory
*Coordination of movement
*Emotional aspects of movement (e.g. physical anger response)
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Internal Control: Brainstem
-White matter contains ascending and descending tracts of nerves between cerebral cortex and spinal cord
-Some tracts originate in the brainstem
-Motor tracts travelling down through the brainstem are influenced by the cerebellum. Both Play an important
-Some tracts originate in the brainstem
-Motor tracts travelling down through the brainstem are influenced by the cerebellum. Both Play an important
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Internal Control: Reticular formation
-Diffuse neurons in the brainstem projecting to all of cerebrum- controls arousal and attention
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Internal Control: Cerebellum
-Develops, stores and updates motor skills; responsible for unconscious movement e.g. balance reactions
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Spinal Cord
-H-shaped central core of grey matter with anterior and posterior horns; surrounded by white matter
-White matter- tracts of nerve fibres carrying impulses up (sensory) and down (motor)
-Grey matter- anterior (motor neurons); posterior (sensory neurone);
-White matter- tracts of nerve fibres carrying impulses up (sensory) and down (motor)
-Grey matter- anterior (motor neurons); posterior (sensory neurone);
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Spinal Reflex
-Regulates local activity between Sc and muscles
-Stretch reflex - stops you from overstretching a muscle
-Flexor or pain reflex - pulls away from a harmful stimulus
-Stretch reflex - stops you from overstretching a muscle
-Flexor or pain reflex - pulls away from a harmful stimulus
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Peripheral Nervous System
-Transmits information to and from the brain and spinal cord
-Bilateral system of paired nerves. Cranial nerves leave the brain and spinal nerves leave the spinal cord.
-Bilateral system of paired nerves. Cranial nerves leave the brain and spinal nerves leave the spinal cord.
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Neural tracts
-Pathways to and from the brain - motor and sensory
-E.g. Pain, crude touch and temperature
-Pain and temperate pathway/spinothalamic tract
-E.g. Pain, crude touch and temperature
-Pain and temperate pathway/spinothalamic tract
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Autonomic Nervous System
-Slower than the somatic system
-Involuntary
-Two neurons between the central NS and the effector organ, explaining the delay.
-Autonomic ganglion is the junction between the two neurons
-Preganglionic neurons in cranica or spinal nerves
-Sympathetic
-Involuntary
-Two neurons between the central NS and the effector organ, explaining the delay.
-Autonomic ganglion is the junction between the two neurons
-Preganglionic neurons in cranica or spinal nerves
-Sympathetic
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Other cards in this set
Card 2
Front
Divided into two principle parts:
-The Central Nervous system
-The Peripheral Nervous System
-The Central Nervous system
-The Peripheral Nervous System
Back
Components of the nervous system
Card 3
Front
-Brain
-Spinal Cord
-Integrating 'command' centre
-Interprets incoming info and dictate responses
-Spinal Cord
-Integrating 'command' centre
-Interprets incoming info and dictate responses
Back
Card 4
Front
-Sensory (afferent) division
-Impulses to the CNS from skin, skeletal muscles, joints, organs.
-Keeps CNS informed of what is going on inside and outside of the body.
-Impulses to the CNS from skin, skeletal muscles, joints, organs.
-Keeps CNS informed of what is going on inside and outside of the body.
Back
Card 5
Front
-Motor (efferent) division
-Impulses from the CNS to efferent organs, muscles and glands to bring about a motor response
-Somatic (to skeletal muscles) - voluntary
-Autonomic (to smooth muscles in organs, cardiac muscles and glands)- involuntary
-Impulses from the CNS to efferent organs, muscles and glands to bring about a motor response
-Somatic (to skeletal muscles) - voluntary
-Autonomic (to smooth muscles in organs, cardiac muscles and glands)- involuntary
Back
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