The papillary layer

Examples of The papillary layer in the following topics:

• 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.
  • The dermis is a tough layer of skin.
  • The dermis is composed of two layers.
  • They are the papillary layer (the upper layer) and the reticular layer (the lower layer).
  • The papillary layer provides the layer above it, the epidermis, with nutrients to produce skin cells called keratinocytes.

• Metabolic Functions

  • The integumentary system is the largest of the body's organ systems, made up of the skin and its associated appendages.
  • The human skin consists of three major layers: the epidermis, dermis, and hypodermis.
  • The epidermis forms the outermost layer, providing the initial barrier to the external environment.
  • 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.
  • The deepest layer is the hypodermis, which is primarily made up of adipose tissue.

• Blood Supply to the Epidermis

  • The epidermis does not contain blood vessels; instead, cells in the deepest layers are nourished by diffusion from blood capillaries that are present in the upper layers of the dermis.
  • The papillary region is composed of loose areolar connective tissue.
  • The reticular region lies under the papillary region and is usually much thicker.
  • 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.

• Burns

  • Most burns affect only the first two layers of the skin, the epidermis and dermis.
  • In the latter system, burns are classified as first, second, third, or fourth degree burns based on the depth of injury to the dermis.
  • Second degree burns extend into the superficial papillary dermis .
  • Fourth degree burns involve all the skin layers as well as the underlying muscle and bone .
  • The majority of these fatalities occur either at the scene or on the way to hospital.

• Operation of Atrioventricular Valves

  • The atrioventricular valves separate the atria from the ventricles and prevent backflow from the ventricles into the atria during systole.
  • The subvalvular apparatus includes the chordae tendineae and the papillary muscles.The atrioventricular valves are anchored to the wall of the ventricle by chordae tendineae (heart strings), small tendons which prevent backflow by stopping the valve leaflets from inverting.
  • The chordae tendineae are inelastic, and are attached at one end to the papillary muscles and at the other end to the valve cusps.
  • Papillary muscles are finger-like projections from the wall of the ventricle that anchor the chordae tendinaea.
  • The tricuspid valve functions similarly to the bicuspid valve, except that three chordae tendinaea connect the cusps of the valve to three papillary muscles, rather than the pairthat connects the bicuspid valve.

• Mucosa

  • The mucosa is the innermost layer of the gastrointestinal (GI) tract, composed of simple epithelium cells.
  • It is the absorptive and secretory layer of the GI tract.
  • The GI tract is composed of four layers.
  • The mucosa is the innermost layer, and functions in absorption and secretion.
  • The most variation is seen in the epithelium tissue layer of the mucosa.

• Serosa

  • Serosa consists of a secretory epithelial layer and a thin connective tissue layer that reduce the friction from muscle movement.
  • Each serous membrane is composed of a secretory epithelial layer and a connective tissue layer underneath.
  • The epithelial layer, known as mesothelium, consists of a single layer of avascular flat nucleated cells (simple squamous epithelium) which produce the lubricating serous fluid.
  • The connective tissue layer provides the blood vessels and nerves for the overlying secretory cells, and also serves as the binding layer which allows the whole serous membrane to adhere to organs and other structures.
  • The layer in contact with the organ is known as the visceral layer, while the parietal layer is in contact with the body wall.

• Muscularis

  • The muscularis externa consists of an inner circular layer and a longitudinal outer muscular layer.
  • The circular muscle layer prevents food from traveling backward and the longitudinal layer shortens the tract.
  • The layers are not truly longitudinal or circular, rather the layers of muscle are helical with different pitches.
  • Between the two muscle layers are the myenteric or Auerbach's plexus.
  • This is the inner oblique layer, and helps churn the chyme in the stomach.

• What is Skin?

  • The epidermis is a thin layer of skin. 
  • It is the most superficial layer of skin, the layer you see with your eyes when you look at the skin anywhere on your body. 
  • This layer is found only on the palms of the hands, fingertips, and the soles of the feet. 
  • The deepest layer of the skin is called the subcutaneous layer, the subcutis, or the hypodermis. 
  • Importantly, the subcutis contains a layer of fat. 

• Layers of the Heart Walls

  • The heart wall is comprised of three layers: the outer epicardium, the middle myocardium, and the inner endocardium.
  • The outer layer of the heart wall is the epicardium.
  • The epicardium refers to both the outer layer of the heart and the inner layer of the serous visceral pericardium, that is attached to the outer wall of the heart.
  • The epicardium is a thin layer of elastic connective tissue and fat, and serves as an additional layer of protection from trauma or friction for the heart under the pericardium.
  • The middle layer of the heart wall is the myocardium—the muscle tissue of the heart and the thickest layer of the heart wall.