dendrite

Examples of dendrite in the following topics:

• Neurons

  • While some neurons have no dendrites, other types of neurons have multiple dendrites.
  • Dendrites can have small protrusions called dendritic spines, which further increase surface area for possible synaptic connections .
  • A bipolar neuron has one axon and one dendrite extending from the soma.
  • Each multipolar neuron contains one axon and multiple dendrites.
  • They also have more specialized structures, including dendrites and axons.

• Regulating Immune Tolerance

  • APCs of the mucosal immune system are primarily dendritic cells, with B cells and macrophages playing minor roles.
  • The pocket contains antigen-presenting cells, such as dendritic cells, which engulf the antigens, then present them with MHC II molecules on the cell surface.
  • The dendritic cells migrate to an underlying tissue called a Peyer's patch.
  • Other antigen-loaded dendritic cells migrate through the lymphatic system where they activate B cells, T cells, and plasma cells in the lymph nodes.

• Cytotoxic T Lymphocytes and Mucosal Surfaces

  • Lymph nodes scattered throughout the body house large populations of T and B cells, dendritic cells, and macrophages .
  • The spleen houses B and T cells, macrophages, dendritic cells, and NK cells .

• Pathogen Recognition

  • PRRs are molecules on macrophages and dendritic cells which are in contact with the external environment and can thus recognize PAMPs when present.
  • Dendritic cells bind molecular signatures of pathogens, promoting pathogen engulfment and destruction.
  • Both macrophages and dendritic cells engulf pathogens and cellular debris through phagocytosis.
  • Neutrophils, dendritic cells, and macrophages release chemicals to stimulate the inflammatory response.

• Reception and Transduction

  • An olfactory receptor, which is a dendrite of a specialized neuron, responds when it binds certain molecules inhaled from the environment by sending impulses directly to the olfactory bulb of the brain.
  • Each neuron has a single dendrite buried in the olfactory epithelium; extending from this dendrite are 5 to 20 receptor-laden, hair-like cilia that trap odorant molecules.

• Somatosensory Receptors

  • A free nerve ending is an unencapsulated dendrite of a sensory neuron; they are the most common nerve endings in skin.
  • Pacinian receptors detect pressure and vibration by being compressed which stimulates their internal dendrites.

• Nerve Impulse Transmission within a Neuron: Action Potential

  • Transmission of a signal within a neuron (in one direction only, from dendrite to axon terminal) is carried out by the opening and closing of voltage-gated ion channels, which cause a brief reversal of the resting membrane potential to create an action potential .
  • When neurotransmitter molecules bind to receptors located on a neuron's dendrites, voltage-gated ion channels open.

• Cell-Mediated Immunity

  • First, an antigen-presenting cell (APC, such as a dendritic cell or a macrophage) detects, engulfs (via phagocytosis in the case of macrophages or by entry of the pathogen of its own accord in the case of dendritic cells), and digests pathogens into hundreds or thousands of antigen fragments.

• Forms of Signaling

  • A nerve cell consists of a cell body, several short, branched extensions called dendrites that receive stimuli, and a long extension called an axon, which transmits signals to other nerve cells or muscle cells.
  • When these impulses reach the end of the axon, the signal continues on to a dendrite of the next cell by the release of chemical ligands called neurotransmitters by the presynaptic cell (the cell emitting the signal).

• Muscle Tissues and Nervous Tissues

  • Projections from the cell body are either dendrites, specialized in receiving input, or a single axon, specialized in transmitting impulses .
  • The neuron has projections called dendrites that receive signals and projections called axons that send signals.