integumentary system Flashcards
(6 cards)
integumentury system basics
The integumentary system is the body’s first line of defense and plays many essential roles in protection, regulation, and sensation. Here’s a quick breakdown of its components and their functions. The skin is a complex organ with multiple layers, each with specific roles in protection, temperature regulation, and waste excretion.
body membranes
Definition: Body membranes are thin layers of tissue that cover surfaces, line body cavities, and protect the body. Many also secrete lubricating fluids to reduce friction.
there are two types of body membranes.
epithial membranes:
which has
Cutaneous Membrane
. Mucous Membrane (Mucosa)
Serous Membrane (Serosa)
conective membranes
synovial membranes
epithial cavities
The epithelial membranes, also called covering and lining membranes, include the cutaneous membrane (skin), the mucous membranes, and the serous membranes (Figure 4.1). However, calling these membranes “epithelial” is misleading because it is not the whole story. Although they all do contain an epithelial layer, it is always combined with an underlying layer of connective tissue. Hence these membranes are actually simple organs. Because we will discuss the skin in detail shortly, we will list it here solely as a subcategory of the epithelial membranes.
mucous membrane
A mucous (myu′kus) membrane (mucosa) is composed of epithelium (the type varies with the site) resting on a loose (areolar) connective tissue membrane called a lamina propria (Figure 4.1b). This membrane type lines all body cavities that open to the exterior, such as those of the hollow organs of the respiratory, digestive, urinary, and reproductive tracts. Notice that the term mucosa refers only to the location of the epithelial membranes, not their cellular makeup, which varies. However, most mucosae contain either stratified squamous epithelium (as in the mouth and esophagus) or simple columnar epithelium (as in the rest of the digestive tract). In all cases, they are moist membranes that are almost continuously bathed in secretions or, in the case of the urinary mucosae, urine.
The epithelium of mucosae is often adapted for absorption or secretion. Although many mucosae secrete mucus, not all do. The mucosae of the respiratory and digestive tracts secrete large amounts of protective, lubricating mucus; that of the urinary tract does not.
serous membrane
A serous membrane, or serosa, is composed of a layer of simple squamous epithelium resting on a thin layer of areolar connective tissue. In contrast to mucous membranes, which line open body cavities, serous membranes line compartments in the ventral body cavity that are closed to the exterior.
Serous membranes occur in pairs (Figure 4.1c). The parietal (pah-ri′ĕ-tal: parie = wall) layer lines a specific portion of the wall of the ventral body cavity. It folds in on itself to form the visceral (vis′er-al) layer, which covers the outside of the organ(s) in that cavity.
You can visualize the relationship between the serosal layers by pushing your fist into a limp balloon only partially filled with air (Figure 4.1d). The part of the balloon that clings to your fist can be compared to the visceral serosa clinging to the organ’s external surface. The outer wall of the balloon represents the parietal serosa that lines the walls of the cavity and that, unlike the balloon, is never exposed but is always fused to the cavity wall.
In the body, the serous layers are separated not by air but by a scanty amount of thin, clear fluid, called serous fluid, which is secreted by both membranes. Although there is a potential space between the two membranes, they tend to lie very close to each other. The lubricating serous fluid allows the organs to slide easily across the cavity walls and one another without friction or pain as they carry out their routine functions. This is extremely important when mobile organs such as the pumping heart and expanding lungs are involved.
The specific names of the serous membranes depend on their locations. The serosa lining the abdominal cavity and covering its organs is the peritoneum (per″ĭ-to-ne′um). In the thorax, serous membranes isolate the lungs and heart from one another. The membranes surrounding the lungs are the pleurae (ploo′re); those around the heart are the pericardia (per″ĭ-kar′de-ah).
synovial membrane
Not made of epithelial cells — instead, made of fibrous areolar connective tissue.
They form the capsules around joints (fibrous capsules) to protect bones where they meet.
They also wrap around bursae (fluid-filled cushions) and tendon sheaths (tubes around tendons).
Synovial membranes produce synovial fluid, which lubricates joints and tissues, reducing friction and allowing smooth movement.
