Best Answer: The double-layered membrane called the PERICARDIUM surrounds the human heart like a sac. * Additional info if you are interested.The outer layer of the pericardium surrounds the roots of the heart's major blood vessels and is attached by ligaments to the spinal column, diaphragm, and other parts of the body. The inner layer of the pericardium is attached to the heart muscle.he membrane the directly covers the heart is called the visceral pericardium....but there is also a membrane around this membrane, forming a cavity, that is called the parietal pericardium. Syd Â· 8 years ago. Thumbs up. 0. Thumbs down. 0.
Awns are characteristic of various plant families, including Geraniaceae and many grasses . In grasses awns typically extend from the lemmas of the florets. This often makes the hairy appearance of the grass synfloresce. Awns may be long (several centimeters) or short, straight or curved, single or multiple per floret. Some genera are named after their awns, such as the three-awns (Aristida). In some species, the awns can contribute significantly to photosynthesis, as, for example, in barley. The awns of wild emmer wheat spikelets effectively self-cultivate by propelling themselves mechanically into soils.
It may be a: 1  Bradawl, a tool for making holes in wood. 2  Scratch awl, a tool used for marking wood. 3  Stitching awl, a tool for piercing holes in leather.