reticular activating system

Examples of reticular activating system in the following topics:

• Reticular Formation

  • The raphe nuclei form a ridge in the middle of the reticular formation, and directly to its periphery, there is a division called the medial reticular formation.
  • The medial reticular formation is large, has long ascending and descending fibers, and is surrounded by the lateral reticular formation.
  • Injury to the reticular formation can result in irreversible coma.
  • Reticular formation nuclei that modulate activity of the cerebral cortex are part of the reticular activating system.
  • Some imaging studies have shown abnormal activity in this area in people with chronic fatigue syndrome, indicating a high likelihood that damage to the reticular formation is responsible for the fatigue associated with these syndromes.

• Somatic Sensory Pathways

  • The axons of many of these neurons terminate in the thalamus, and others terminate in the reticular activating system or the cerebellum.
  • In the periphery, the somatosensory system detects various stimuli by sensory receptors, such as by mechanoreceptors for tactile sensation and nociceptors for pain sensation.
  • The sensory information (touch, pain, temperature, etc.,) is then conveyed to the central nervous system by afferent neurons, of which there are a number of different types with varying size, structure, and properties.
  • In the spinal cord, the somatosensory system includes ascending pathways from the body to the brain .
  • Note that many ascending somatosensory pathways include synapses in either the thalamus or the reticular formation before they reach the cortex.

• Blood Supply to the Epidermis

  • The reticular region lies under the papillary region and is usually much thicker.
  • The reticular region receives its name from the dense concentration of collagenous, elastic, and reticular fibers that weave throughout it.
  • Blood vessels that supply the capillaries of the papillary region run through the reticular region.
  • Blood vessels that supply the capillaries of the papillary region are seen running through the reticular layer.
  • Identify the source of the blood supply for the integumentary system

• Metabolic Functions

  • The integumentary system is the largest of the body's organ systems, made up of the skin and its associated appendages.
  • The integumentary system distinguishes, separates, and protects the organism from its surroundings, but also plays a key metabolic function, as the major region for vitamin D production.
  • Beneath this, the dermis comprises two sections, the papillary and reticular layers, and contains connective tissues, vessels, glands, follicles, hair roots, sensory nerve endings, and muscular tissue.
  • Vitamin D from the diet or that is synthesized by the body is biologically inactive; activation requires enzymatic conversion in the liver and kidney.

• Structural Elements of Connective Tissue

  • Reticular fibers or reticulin is a histological term used to describe a type of fiber in connective tissue composed of type III collagen.
  • Reticular fibers crosslink to form a fine meshwork (reticulin).
  • This network acts as a supporting mesh in soft tissues such as liver, bone marrow, and the tissues and organs of the lymphatic system.
  • Reticular fiber is composed of one or more types of very thin and delicately woven strands of type III collagen.

• Structure of the Skin: Dermis

  • The dermis consists of a papillary and a reticular layer that serve to protect and cushion the body from stress and strain.
  • They are the papillary layer (the upper layer) and the reticular layer (the lower layer).
  • The reticular layer serves to strengthen the skin and also provides our skin with elasticity.
  • The reticular layer also contains hair follicles, sweat glands, and sebaceous glands.
  • Lymphatic vessels that transport immune system cells, the cells that help destroy infectious organisms that may have found their way into our body via a scratch on the skin.

• Hypothalamus

  • The hypothalamus serves as a gateway between the nervous system and endocrine system.
  • One of the most important functions of the hypothalamus is linking the nervous system to the endocrine system via the pituitary gland (hypophysis).
  • These hormones are released into the bloodstream and target other organ systems, most notably the pituitary.
  • The hypothalamus affects the endocrine system and governs emotional behavior such as anger and sexual activity.
  • The hypothalamus is thus richly connected with many parts of the central nervous system, including the brainstem, reticular formation and autonomic zones, and the limbic forebrain (particularly the amygdala, septum, diagonal band of Broca, olfactory bulbs, and cerebral cortex).

• Basement Membranes and Diseases

  • The basement membrane is the fusion of two lamina: the basal lamina and the reticular lamina (or lamina reticularis).
  • The electron-dense lamina densa membrane is about 30–70 nanometers in thickness, and consists of an underlying network of reticular collagen (type IV) fibrils (fibroblast precursors) which average 30 nanometers in diameter and 0.1–2 micrometers in thickness.
  • The cause can be genetic defects, injuries by the body's own immune system, or other mechanisms.

• Clusters of Neuronal Cell Bodies

  • For example, the reticular nucleus of the thalamus is a thin layer of inhibitory neurons that surround the thalamus.
  • In the peripheral nervous system, a cluster of neurons is called a ganglion.
  • They are the intermediary connections between the peripheral and central nervous systems.
  • Satellite glial cells are a type of glial cell that line the exterior surface of neurons in the peripheral nervous system (PNS) .
  • They are thought to have a similar role to astrocytes in the central nervous system (CNS).

• Aging and the Cardiovascular System

  • Movat stain (black = nuclei, elastic fibers; yellow = collagen, reticular fibers; blue = ground substance, mucin; bright red = fibrin; red = muscle).