membranous labyrinth

Examples of membranous labyrinth in the following topics:

• Development of Hearing and Balance

  • The auditory vesicle will give rise to the utricluar and saccular components of the membranous labyrinth.
  • Beginning in the fifth week of development, the auditory vesicle also gives rise to the cochlear duct, which contains the spiral organ of Corti and the endolymph that accumulates in the membranous labyrinth.
  • The basilar membrane separates the cochlear duct from the scala tympani, a cavity within the cochlear labyrinth.
  • The hair cells develop from the lateral and medial ridges of the cochlear duct, which together with the tectorial membrane make up the organ of Corti.

• Membrane Potentials as Signals

  • Membrane potential (also transmembrane potential or membrane voltage) is the difference in electrical potential between the interior and the exterior of a biological cell.
  • The membrane serves as both an insulator and a diffusion barrier to the movement of ions.
  • Ion transporter/pump proteins actively push ions across the membrane to establish concentration gradients across the membrane, and ion channels allow ions to move across the membrane down those concentration gradients, a process known as facilitated diffusion.
  • The membrane potential has two basic functions.
  • Signals are generated by opening or closing of ion channels at one point in the membrane, producing a local change in the membrane potential that causes electric current to flow rapidly to other points in the membrane.

• Epithelial Membranes

  • The mucous membranes are linings of ectodermal origin.
  • These mucus membranes are involved in absorption and secretion.  
  • These membranes exist in the  hollow organs of the digestive, respiratory, and urogenital tracts.
  • The term "mucous membrane" refers to where they are found in the body; not every mucous membrane secretes mucus.
  • Most mucous membranes contain stratified squamous or simple columnar epithelial tissue.

• Basement Membranes and Diseases

  • The basement membrane anchors epithelium to the connective tissue beneath it.
  • The two layers are collectively known as the basement membrane.
  • The basement membrane is also essential for angiogenesis (development of new blood vessels).
  • Basement membrane proteins have been found to accelerate differentiation of endothelial cells.
  • Some diseases result from a poorly-functioning basement membrane.

• Interosseous Membranes

  • The interosseous membrane is a type of connective tissue found between certain bones in the body.
  • The long bones of the lower arm and the leg both have attached interosseous membranes.
  • The muscles in the leg are separated into sections in the front and back with this membrane.
  • Twisting bones with an attached interosseous membrane in an abnormal or extreme position can damage the membrane, as well as create a fracture in one or both bones.
  • This image shows the interosseous membrane connecting the radius and the ulna.

• Resting Membrane Potentials

  • The potential difference in a resting neuron is called the resting membrane potential.
  • The potential difference in a resting neuron is called the resting membrane potential.
  • This causes the membrane to be polarized.
  • The value of the resting membrane potential varies from -40mV to -90mV in a different types of neurons.
  • The resting membrane potential exists only across the membrane.

• The Action Potential and Propagation

  • Action potential is a brief reversal of membrane potential where the membrane potential changes from -70mV to +30mV.
  • When the membrane potential of the axon hillock of a neuron reaches threshold, a rapid change in membrane potential occurs in the form of an action potential.
  • This moving change in membrane potential has three phases.
  • As additional sodium rushes in, the membrane potential actually reverses its polarity.  
  • As a result, the membrane permeability to sodium declines to resting levels.

• Serous Membranes

  • Serous membranes line and enclose serous cavities, where they secrete a lubricating fluid which reduces friction from muscle movement.
  • In anatomy, a serous membrane (or serosa) is a smooth membrane consisting of a thin layer of cells, which secrete serous fluid, and a thin connective tissue layer.
  • Each serous membrane is composed of a secretory epithelial layer and a connective tissue layer underneath.
  • Therefore, each organ becomes surrounded by serous membrane; they do not lie within the serous cavity.
  • Describe the function of the serous membranes in the pericardial, pleural, and peritoneal cavities

• Postsynaptic Potentials and Their Integration at the Synapse

  • Postsynaptic potentials are changes in the membrane potential of the postsynaptic terminal of a chemical synapse.
  • Many postsynaptic membrane receptors at chemical synapses are specialized to open ion channels.
  • At excitatory synapses, neurotransmitter binding depolarizes the postsynaptic membrane.
  • Unlike the action potential in axonal membranes, chemically-gated ion channels open on postsynaptic membranes.
  • EPSPs and IPSPs are transient changes in the membrane potential.

• Overview of the Axial Skeleton

  • They are contained within the middle ear space and serve to transmit sounds from the air to the fluid-filled labyrinth (cochlea) .