cribriform plate

Examples of cribriform plate in the following topics:

• Foramina

  • Foramina of cribriform plate: Located in the ethmoid bone, it allows the passage of the olfactory nerve.

• Olfactory (I) Nerve

  • The olfactory nerves consist of a collection of many sensory nerve fibers that extend from the olfactory epithelium to the olfactory bulb, passing through the many openings of the cribriform plate of the ethmoid bone.

• Cartilaginous Joints: Synchodroses

  • A temporary form of joint called an epiphyseal (growth) plate, is one where the cartilage is converted into bone before adult life.
  • The epiphyseal plate is a hyaline cartilage plate in the metaphysis at each end of a long bone.
  • The epiphyseal plate is found in children and adolescents.
  • In puberty, increasing levels of estrogen, in both females and males, leads to increased apoptosis of chondrocytes in the epiphyseal plate.
  • In adults who have stopped growing, the plate is replaced by an epiphyseal line.

• Neurulation

  • This strip is called the neural plate, and is the origin of the entire nervous system.
  • The neural plate folds outwards to form the neural groove.
  • The anterior (ventral or front) part of the neural tube is called the basal plate; the posterior (dorsal or rear) part is called the alar plate.
  • In general, it entails the cells of the neural plate forming a cord-like structure that migrates inside the embryo and hollows to form the tube.
  • Transverse sections that show the progression of the neural plate to the neural groove from bottom to top.

• Development of the Peripheral Nervous System

  • In vertebrates, the first sign of the nervous system is the appearance of a thin strip of cells along the center of the back, called the neural plate.
  • The inner portion of the neural plate (along the midline) is destined to become the central nervous system (CNS), the outer portion the peripheral nervous system (PNS).
  • The sequence of stages from neural plate to neural tube and neural crest is known as neurulation .
  • After gastrulation, neural crest cells are specified at the border of the neural plate and the non-neural ectoderm.
  • During neurulation, the borders of the neural plate, also known as the neural folds, converge at the dorsal midline to form the neural tube.

• Nails

  • The fingernail generally serves two purposes: as a protective plate and enhances sensation of the fingertip.
  • The nail plate is the actual fingernail, composed of translucent keratin.
  • The underneath surface of the nail plate has grooves along the length of the nail that help anchor it to the nail bed.
  • The perioncyhium is the skin that overlies the nail plate on its sides.
  • The hyponychium is the area between the nail plate and the fingertip.

• Peripheral Motor Endings

  • A neuromuscular junction exists between the axon terminal and the motor end plate of a muscle fiber where neurotransmitters are released.
  • A neuromuscular junction is the synapse or junction of the axon terminal of a motor neuron with the motor end plate, as shown in Figures 1 and 2.
  • Acetylcholine diffuses into the synaptic cleft and binds to the nicotinic acetylcholine receptors located on the motor end plate.
  • These receptors open to allow sodium ions to flow in and potassium ions to flow out of the muscle's cytosol, producing a local depolarization of the motor end plate, known as an end-plate potential (EPP).
  • The binding of acetylcholine at the motor end plate leads to intracellular calcium release and interactions between myofibrils to elicit contraction.

• Embryonic Development of the Brain

  • This strip is called the neural plate, and is the origin of the entire nervous system.
  • The neural plate folds outwards to form the neural groove.
  • The anterior (front) part of the neural tube is called the basal plate; the posterior (rear) part is called the alar plate.
  • In the fifth week, the alar plate of the prosencephalon expands to form the cerebral hemispheres (the telencephalon).
  • The basal plate becomes the diencephalon.

• Thoracic Cage: Sternum

  • The sternum or breastbone is a long, flat, bony plate connected to the rib bones via cartilage that forms the anterior section of the rib cage.
  • The sternum, or breastbone, is a long, flat, bony plate that forms the most anterior section of the ribcage.

• Embryonic Development

  • Primary neurulation begins after the neural plate has formed.
  • The edges of the neural plate start to thicken and lift upward, forming the neural folds.
  • The center of the neural plate remains grounded allowing a U-shaped neural groove to form.
  • A secondary signaling center is then established in the roof plate, the dorsal most structure of the neural tube.
  • Shh secreted from the floor plate creates a gradient along the ventral neural tube.