dendritic cell

Examples of dendritic cell in the following topics:

• Dendritic Cells

  • Dendritic cells are immune cells that function to process antigens and present them to T cells.
  • Immature dendritic cells (e.g.
  • Subsets of dendritic cells can be distinguished by the expression of cell surface markers.
  • Dendritic cells are constantly in communication with other cells in the body.
  • For example, stimulating dendritic cells in vivo with microbial extracts causes the dendritic cells to rapidly begin producing interleukin 12 (IL-12).

• Phagocytes

  • The main types of phagocytes are monocytes, macrophages, neutrophils, tissue dendritic cells, and mast cells.
  • Most monocytes leave the blood stream after 20–40 hours to travel to tissues and organs; during this process, they differentiate into macrophages or dendritic cells depending on the signals they receive.
  • Dendritic cells are specialized antigen-presenting cells that have long outgrowths called dendrites, which help to engulf microbes and other invaders.
  • Dendritic cells are present in the tissues that are in contact with the external environment, mainly the skin, the inner lining of the nose, the lungs, the stomach, and the intestines.
  • Monocytes differentiate into dendritic cells and macrophages, while mast cells and neutrophils are in a separate group of PMN granuolcytes as well.

• Antigen-Presenting Cells

  • Antigen presentation is a process in the body's immune system by which macrophages, dendritic cells and other cell types capture antigens, then enable their recognition by T-cells.
  • Dendritic cells, B cells and macrophages play a major role in the innate response, also acting as professional antigen-presenting cells (APC).
  • Antigen presentation stimulates T cells to become either "cytotoxic" CD8+ cells or "helper" CD4+ cells.
  • Dendritic cells (DCs) phagocytose exogenous pathogens such as bacteria, parasites, and toxins in the tissues and then migrate, via chemotactic signals, to T cell-enriched lymph nodes.
  • High levels of Class II are found on dendritic cells, but can also be observed on activated macrophages, B cells, and several other host cell types in inflammatory conditions.

• Introducing the Neuron

  • Dendrites are branch-like structures extending away from the cell body, and their job is to receive messages from other neurons and allow those messages to travel to the cell body.
  • Although some neurons do not have any dendrites, other types of neurons have multiple dendrites.
  • Dendrites, cell bodies, axons, and synapses are the basic parts of a neuron, but other important structures and materials surround neurons to make them more efficient.
  • The structure of motor neurons is multipolar, meaning each cell contains a single axon and multiple dendrites.
  • The above image shows the basic structural components of an average neuron, including the dendrite, cell body, nucleus, Node of Ranvier, myelin sheath, Schwann cell, and axon terminal.

• Cell-Mediated Autoimmune Reactions

  • A normal immune response is assumed to involve B and T cell responses to the same antigen, where B cells recognize conformations on the surface of a molecule for B cells, and T cells recognize pre-processed peptide fragments of proteins for T cells.
  • Together with the concept of T cell-B cell discordance, this idea forms the basis of the hypothesis of self-perpetuating autoreactive B cells.
  • Immune system cells called dendritic cells present antigens to active lymphocytes.
  • Dendritic cells that are defective in apoptosis can lead to inappropriate systemic lymphocyte activation and consequent decline in self-tolerance.
  • HLA-DQ (DQ) is a cell surface receptor type protein found on antigen presenting cells.

• Characteristics of Nervous Tissue

  • It consists of neurons and supporting cells called neuroglia.
  • A typical neuron consists of dendrites, the cell body, and an axon.
  • Dendrites are responsible for responding to stimuli; they receive incoming signals towards the cell body.
  • The cell body is like a factory for the neuron.
  • The dendrites receive incoming signals while axons propagate signals away from the neuron cell body.

• Neurons

  • Dendrites are tree-like structures that extend away from the cell body to receive messages from other neurons at specialized junctions called synapses.
  • While some neurons have no dendrites, other types of neurons have multiple dendrites.
  • Once a signal is received by the dendrite, it then travels passively to the cell body.
  • For example, dendrites from a Purkinje cell in the cerebellum are thought to receive contact from as many as 200,000 other neurons.
  • The Purkinje cell, a multipolar neuron in the cerebellum, has many branching dendrites, but only one axon.

• Structural Diversity of Neurons

  • A typical neuron consists of a cell body and neuronal processes such as dendrites and axon.
  • The dendrites are short, tapering extensions that are the receptive regions and help in conveying incoming messages towards the cell body.
  • Bipolar neurons have two processes, an axon and a dendrite, that extend from opposite ends of the soma.
  • Multipolar neurons, the most common type, have one axon and two or more dendrites.
  • A signal propagating down an axon to the cell body and dendrites of the next cell

• Types of Nervous Tissue

  • In the PNS, satellite cells and Schwann cells are the two kinds of neuroglia.
  • Satellite cells surround neuron cell bodies in the peripheral nervous system (PNS).
  • The two types of neuron processes are called dendrites and axons.
  • Dendrites are motor neurons that are short and have a large surface area for receiving signals from other neurons.
  • Dendrites convey incoming messages towards the cell body and are therefore called the receptive input region.

• Electric Potential in Human

  • Resting membrane potential is approximately -95 mV in skeletal muscle cells, -60 mV in smooth muscle cells, -80 to -90 mV in astroglia, and -60 to -70 mV in neurons.
  • Potentials can change as ions move across the cell membrane.
  • Neurons receive an impulse at the dendrites.
  • When the signal reaches the end of the axon, neurotransmitters are released, which then are received by the dendrites of the next neuron.
  • Neurons receive an impulse at the dendrites.