BIOL10002 Lecture Notes - Macrophage, Blood Plasma, Prostaglandin
Week 9
Lecture 23
The Nervous System, part 1
Basics of nerve function
Membrane potential in resting state is more negative inside relative to outside.
Activation of cells caused by depolarisation;
Charge difference switches to being more positive inside due to ion movement
When something is depolarised, it is activated.
Inhibition of cells caused by hyperpolarisation;
Charge difference becomes more negative than resting potential, therefore harder to depolarise
When something is hyperpolarised, it is unresponsive
Neurons
store energy in the form of electrical potential difference and use this to transmit action potentials
More dendrites = more inputs that can be processed
Specialised neurons include;
Cerebellum
Retina (sensory neuron)
Cerebral cortex
sensory neurons have fewer dendrites as they only need to receive specific stimuli
Glia
provide support, nourishment and insulation to neurons
Wraps terminal around the axon of a neuron
do not transmit electrical signals but can release transmitters – glia transmitters
give support during development, supply nutrients, and maintain the interstitial environment
Can assist in neuronal repair.
Oligodendrocytes = CNS insulate & increase speed of communication between neurons, made of lipids
Schwann cells = PNS
Nervous system
Central nervous system - brain and spinal cord
Peripheral nervous system - everything else
- Somatic nervous system (voluntary)
- Autonomic nervous system (involuntary)
Parasympathetic (rest and digest) – decrease heart rate and contractility, increase blood flow to the digestive
system, decrease blood flow to skeletal muscles
Sympathetic (fight or flight) - opposite
Afferent neurons (sensory) carry sensory information to the CNS
- dendrites found in the skin, muscle, organs
- terminals end in the spinal cord, connected to interneurons
Efferent neurons (motor) carry sensory information from the CNS
- dendrites found in the spinal cord
- terminals found in muscles or organs
Interneurons enable communication between afferent and efferent neurons and the CNS
Sensory systems
neurons receive sensory inputs from specialised receptors, which are either modified neurons or modified cells
that are connected to neurons
sensory systems transduce external and internal environmental stimuli into action potentials
Sensory neurons are nerve cells that transduce (convert) external stimuli into action potentials.
Sensory cell receptor proteins respond to stimuli by directly or indirectly opening or closing ion channels in the
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Document Summary
Membrane potential in resting state is more negative inside relative to outside. Charge difference switches to being more positive inside due to ion movement. When something is depolarised, it is activated. Charge difference becomes more negative than resting potential, therefore harder to depolarise. When something is hyperpolarised, it is unresponsive. Store energy in the form of electrical potential difference and use this to transmit action potentials. More dendrites = more inputs that can be processed. Sensory neurons have fewer dendrites as they only need to receive specific stimuli. Provide support, nourishment and insulation to neurons. Wraps terminal around the axon of a neuron. Do not transmit electrical signals but can release transmitters glia transmitters. Give support during development, supply nutrients, and maintain the interstitial environment. Oligodendrocytes = cns insulate & increase speed of communication between neurons, made of lipids. Central nervous system - brain and spinal cord.
