| what are nervous systems made up of? | Nerve cells and glial cells. |
| What is the function of Glial cells? | To provide support functions to neurons by playing an information processing role. |
| What is the basic plan of a neuron? | Contain a cell body, holding most of the cytoplasm and organelles. Also dendrites, that recieve signals and carry them to the soma. Axons are fibres that carry impulses away from the cell. Finally axon terminals which form a synapse with the target cell. |
| What are the functions of Glial cells? | To provide structural and metabolic support to the neuron, such as myelination. |
| What is myelination and where is it found? | Found in vertebrates, myelin sheaths surround the axons and increase their conductivity by secreting myelin, fat, improving transmission speeds. |
| What is a synapse? | The space between axon terminals and dendrites where information is transmitted. |
| List the three basic neurons and their function? | 1. Afferent, receive information from internal or external stimulus and transmit information to another neuron.
2. Interneurons, transmit information from one neuron to another. can integrate multiple signals from multiple sources.
3. Efferent, receives information from another neuron and mediate it to an effector organ. |
| What was the first step in the evolution of the nervous system? | Basal structure where the sensory neuron also activated the effector cell, was only a singular nerve cell. |
| How did nervous systems evolve from basal structures? | The functional separation into sensory and motor neurons, information was transferred via a synapse located in a central nervous system. |
| How did the central nervous system form and in which family did it first come around? | The central nervous system first formed in marine invertebrates Platyhelminthes. Where neurons became more clustered into morphologically and functionally distinct units called ganglia. |
| How did symmetry effect the evolution of nervous systems? | Bilaterally symmetrical animals, evolved ventral or dorsal nerve cords. Where as radially symmetrical echinoderms evolved to have a nerve ring with radiating nerves. Finally, molluscs have an asymmetrical nervous system. |
| What are the characteristics of a nerve net? | Nerve nets don't have interneurons and lack a CNS. Functional polarity of each neuron ensures a unidirectional flow of information |
| How can segmentation effect nervous system structure? | Segmentation results in a each segment having a ganglion in each body segment along the ventral nerve cord. Each ganglion is responsible for the reflex function of each segment. |
| what 2 processes facilitated the evolution of a complex nervous system? | Both centralisation, the combining of neurons into a functional unit like ganglia, and specialisation, through increasing the different types of neurons. |
| Detail the two divisions of a vertebrate nervous system: | Peripheral nervous system, anything that is not the brain or spinal cord.
Central nervous system, consists of the spinal cord and brain. |
| Detail the functions of the central nervous system parts. | Spinal cord, conducts signals too and from the brain and controls reflex activities.
Brain, receives and processes sensory information and initiates a response. |
