1. Neuroanatomy I Flashcards
Describe the PNS.
PNS in the nerves outside the CNS.
Has two main Divisions.
-Sensory (Afferent) Division. information coming into the body and CNS
-Motor (Efferent) Division. Information coming from the CNS to muscles, glands, etc. is further split into two divisions,
Describe the two main divisions of the Motor (Efferent) Division.
1 .Visceral/Autonomic motor division, Autonomic NS parasympathetic and sympathetic NS
2 .Somatic Motor Division. Voluntary Skeletal movement.
Describe the CNS.
-Brain and spinal cord.
-Control centre for information processing and responding to sensory information.
Describe Neurons.
-Made up of cell body, nucleus, axon and dendrites.
-Receive stimuli.
-Transmit nerve impulses or action potentials.
-Capacity to activate muscles.
-All organisms with a nervous system will have Neurons.
Describe Dendrites.
Collect electrical signals and carry input to the cell body.
Describe the Cell body/Soma.
Integrates signals and generates action potentials.
Describe an Axon.
Transmits signals over long distances from the cell body to the axon terminals. It can be myelinated.
Describe what Invertebrate Nervous systems are specialised for.
-Stimulus/response, receptor/effector.
-Reflexes, conditioned responses.
-Lacks myelin but action potential propagation is overcome by increasing the diameter of axons
Name the 4 types of Nervous syetems.
-Nerve Nets
-Cephalisation, with ganglia chains and Nerve Trunks.
-Central Nervous System.
-Peripheral Nervous system.
Describe Nerve Net Nervous systems.
-Simplified form of nervous system found in some invertebrates.
-Individual nerve cells exist in a net-like formation scattered in layers of the body wall. Neurons exist in a ‘loose network’ to allow for contraction and expansion of the body cavity.
-Can carry information from sensory organs that detect touch, light or changes in the environment.
-They can contact neurons that control the movement of the organism.
-Nerve signals can travel in both directions.
Describe what Nerve net systems lack.
-Distinct Central or peripheral regions and anything that resembles a brain.
-No associative activity, just reflexes with action potentials.
Describe Cephalisation and formation of the primitive brain.
In animals with Bilateral symmetry, there is a clustering of neurons into ’ganglia’ near the head of the animal to form more complex systems to integrate incoming/outgoing signals (seeing, hearing, tasting, etc.), often by forming nerve trunks running down the animal.
Describe what Vertebrate Nervous systems contain.
-Sophisticated Sensory mechanism.
-Clear differentiation of CNS and PNS as well as sensory and motor nerves.
-advanced brain structure.
Describe Sulci.
Infoldings of the cerebral hemispheres that form valleys between the gyri.
Describe Gyri.
The ridges of the infolded cerebral hemispheres.
