2021年口腔生理學(xué)術(shù)語(yǔ)(L)

1、口腔生理學(xué)術(shù)語(yǔ)(L) lamella-bone - the microscopic structure of cortical bone gives it the appearan _ of con _ntric or parallel plates ( from latin, lamella, the diminutive of lamina, meaning a plate or leaf). lamina propria - the layer of loose connective tissue underneath the epithelium of mucosa, which pr

2、ovides physical and nutritional support. lamina-dura - the name given to the radiographic appearan _ of a dense layer of bone around the tooth root. it represents the dense cortical bone lining the tooth socket. laminin - an adhesive molecule of connective tissue related to fibronectin andtenascin.

3、langherhans _lls are active in the immune response of the skin and mucous membrane. they act as sentries, detecting the presen _ of foreign antigens on the su _ _ of the epithelium. they do not contain keratin and are thus sometimes called clear _lls. lectin - a protein molecule which bindson to a s

4、pecific sequen _ of sugars. bacteria _y use lectin attachments to bind onto each other or oral su _ _s. leucocytes - un pigmented (white) _lls of the blood. those with granular cy la _ are neutrophils, eosinophils and basophils. the agranulocytes are lymphocytes and monocytes. leucotriens- con _rned

5、 with signalling between _lls of the immune system and a member of the eicosanoid family of hormones. ligand - a protein molecule which binds to another specific protein molecule. the for _s of the bond are week and thus protein-ligand bonds depend on close fit of one molecule to the other, so as to

6、 capture as _ny bonding sites as possible. ligands are specific for a particular protein. they are found on _ll su _ _s of microorgani _s where they assist in _ll adhesion. they are also sights on _ll membranes onto which protein messengers attach such ascytokines (see also lectins). limbic system -

7、 a ring of structures around the thalamus which play a _jor role in pain as well as other types of behaviour. the limbic system includes the hypothalamus, hippocampus, amygdala, septum and cingulum. the limbic system plays an important role in pain at the level of motivation to avoid it. it thus ope

8、rates at a slightly higher level than the reticular for _tion with strong connections to the thalamus and cortex. lipid - - large molecules containing hydrogen and carbon which are insoluble in water. _ lipids consist of long chains of fatty acids. pound lipids contain phosphoric acid, sugars, nitro

9、genous bases or proteins, and include the phospholipids, glycolipids and lipoproteins. steroids _y also be classified as lipids. lubrication - helping two su _ _s to slide over each other. lycine - one of 20 aminoacids mon in proteins. it is a mon amino acid of collagen and like proline must be hydr

10、oxylated by ascorbic acid in order to allow the for _tion of bonds which will hold the triple helix together. lymphocytes - white _lls involved in the immune response. b lymphocytes are so called because they _ture in bone while t lymphocytes _ture in the thymus. both _lls look alike until they reco

11、gnise a foreign antigen. the b _ll starts to _ke antibo _s while the t lymphocytes aumulate vesicles loaded with cytotoxic agents. on contact with a foreign _ll, the lymphocytes changes shape so that all it vesicles are pointed at the enemy. the release of cytotoxic agents need to be carefully contr

12、olled. one of the methods by which the enemy _ll is killed is by agents which _ke holes in its _ll membrane. enemy _lls _ybe bacteria, or the bo _s own _lls which have ingested viruses or they _y be can _r _lls, or the _lls of transplanted organs. lymphokines - a variety of cytokines released by lym

13、phocytes which coordinate the proliferation of t and b lymphocytes. they also regulate the brains contribution to the immune response via the hypothalamus - adrenal cortex axis. lysosomes - s _ll membrane bound vesicles in the cy la _ of _lls which contain toxic enzymes. when a _ll _s, these membranes rupture and the enzymes are released. they break down the _lls structure, and the debris is removed. the lysosome also contains cyto