module 1 Flashcards
Function of Astrocytes?
- deliver nutrients from blood, draining waste products
- controls chemical environment and microenvironment
- controls capillary blood flow
- repairs and helps scarring of nerve cells in CNS
- can release glycogen when necessary
Function of Oligodendrocytes and Schwann cells?
- provides myelin sheath(fatty insulator material) around some axons
Oligodendrocytes: CNS
Schwann cells: PNS
Function of Microglia?
- scavenge cell debris, removes toxic materials, a type of macrophage only in CNS
- can reorganize their shape and change their processes, while keeping the cell body the same
Function of Ependymal cells?
- lines the ventricles(brain’s fluid spaces) and creates a barrier
- creates and secretes cerebrospinal fluid
- cilia on the surface of the cell systematically allow the cell to release cerebrospinal fluid
- are able to influence the distribution of neurotransmitters to neurons
- some can multiply and divide to form neurons
- protects axon stumps from degeneration after damage, can help nerve regeneration
Difference between tropic and trophic
Tropic: a hormone that turns to chemical transmitters to incite another gland into secreting another hormone
Trophic: a molecule that aids in the health and growth of other molecules and cells
Parts of a neuron?
Cell body/soma: contains nucleus and organelles, the main part of the cell
Dendrites: receives information from other neurons to pass through soma
Axon: transporting signals from dendrites/soma to axon terminals
Axon terminals: releases neurotransmitters to pass information to other cells
Parts of a neuron?
Cell body/soma: contains nucleus and organelles, the main part of the cell
Dendrites: receives information from other neurons to pass through soma
Axon: transporting signals from dendrites/soma to axon terminals
Axon terminals: releases neurotransmitters to pass information to other cells
Axon hillock/initial segment: collects information from different inputs and decides whether to pass it on
Skeleton: consists of neuro/microfilaments for rigidity, provides a base structure for neuron
More: functions of astrocytes
- Maintains the blood-brain barrier, made up of endothelial cells
- End-feet of astrocytes stop leaks and provide structural support
- Regulates the amount of neurotransmitter emitted to prevent toxicity
- Removes excess potassium to maintain homeostasis
Difference between autonomic and somatic nervous systems
Autonomic: neurons located in deep internal structures which regulate involuntary movements
Somatic: neurons located in superficially located structures that regulates voluntary movements
Difference between nuclei/fields and ganglia
Nuclei: a structure of a cluster of cell bodies in the CNS
Ganglia: a structure of a cluster of cell bodies in the PNS
Difference between a nucleus and axon tract
The nucleus is the gathering area of cell bodies, while axon tracts are the collection of axons running together to other parts of the body
Sensory Afferent + Motor Efferent
Sensory afferent: the nerves which take information from other parts of the body to the CNS for processing
Motor efferent: the nerves which take information from the CNS to direct other parts of the body into movement
Other neuron classifications
- Interneurons: neurons that relay information from one neuron to another(either in the same nuclei or in different ones), only found in the CNS
- Neuroendocrine cells: a cell which, when stimulated, releases hormones into the bloodstream to influence distant target organs
Types of cell structures
- Unipolar: axons, soma, no dendrites(rather rare in humans)
- Pseudo-unipolar: soma in the middle, axons on both sides to pass the information on
- Bipolar: one dendrite, one axon, soma
- Multipolar: one axon, soma, many dendrites
Difference between axon and axon hillock
Axon: Conducting region of the cell, transports information from the soma to axon terminals
Axon hillock/Initial segment: Found between the axon and soma, receives inputs and determines whether or not the information should be passed on
Function of the neuron skeleton
Skeleton: a structure made from micro and neurofilaments meant to give the cell a base structure. Includes microtubules for transport.
Function of dendrite spines
Spine: an extension of the dendrites, meant to receive excitatory input from the axon terminal of another cell
- a spine’s shape can be changed through actin, a protein that allows muscles to elongate
Types of dendrite spines
Thin: Known as
learning spines’, and will grow when a new task is learned
Larger mushroom spines: Know as ‘memory spines’, and are grown from thin spines when tasks are remembered
Parts of the Cytoskeleton
- made up of microfilaments and neurofilaments for rigidity and shape
- consists of microtubules(creates a structure similar to a conveyor belt) to assist with transportation
- can transport nutrients, waste products and chemical neurotransmitters to other cells
- when the cytoskeleton/microtubules are damaged, organelles and particles meant to be transported by the microtubules collect within the neuron and eventually lead to neuronal death
Process of the Myelination of a Neuron
The glial cell(either an oligodendrocyte or Schwann cell) wraps itself around a part of the axon, and winds itself tighter and tighter to create better insulation
Function of a synapse
- where a neuron contacts another cell to relay commands or information
- space between two cells is known as the synaptic cleft
- chemical neurotransmitters are used to carry information or commands, from the signalling neuron to the target cell
