sac

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Related to alveolar sacs: alveolus, alveoli

sac

 [sak]
a baglike organ or structure; see also bag, pocket, and pouch.
air s's (alveolar s's) the spaces into which the alveolar ducts open distally, and with which the alveoli communicate; see also lung.
amniotic sac the sac formed by the amnion, enclosing the fetus suspended in amniotic fluid; popularly known as the bag of waters.
conjunctival sac the potential space, lined by conjunctiva, between the eyelids and the eyeball.
endolymphatic sac the blind, flattened cerebral end of the endolymphatic duct.
hernial sac the peritoneal pouch that encloses protruding intestine.
lacrimal sac the dilated upper end of the nasolacrimal duct; see also lacrimal apparatus.
yolk sac the extraembryonic membrane connected with the midgut; in vertebrates below true mammals, it contains a yolk mass.
Yolk sac in a developing embryo. From Applegate, 2000.

sac

(sak), Do not confuse this word with sack.
1. A pouch or bursa.
See also: sacculus. Synonym(s): saccus
2. An encysted abscess at the root of a tooth.
3. The capsule of a tumor, or envelope of a cyst.
[L. saccus, a bag]

sac

(săk)
n.
A pouch or pouchlike structure in an organism, sometimes filled with fluid.

sac

A pouch or other enclosed anatomic structure.

SAC

Abbreviation for:
seasonal acute conjunctivitis
serous adenocarcinoma
Sexual Addiction and Compulsion
Specialty Advisory Committee, see there 
splinting for acute closure
standardised assessment of concussion
stoma appliance customisation
substance abuse counsellor

sac

Medtalk A pouch or other enclosed structure. See Alveolar sac, Gestational sac, Pouch, Yolk sac.

sac

(sak)
1. A pouch or bursa.
Synonym(s): saccus [TA] .
2. An encysted abscess at the root of a tooth.
3. The capsule of a tumor, or envelope of a cyst.
See also: sacculus
[L. saccus, a bag]

sac

Any bag-like organ or body structure.

sac

a bag-like or pouched structure.

sac

(sak)
1. Encysted abscess at the root of a tooth.
2. Pouch or bursa.
3. Capsule of a tumor, or envelope of a cyst.
[L. saccus, a bag]

Patient discussion about sac

Q. what does it mean when an ultrasound shows an empty amniotic sac and no baby?

A. This exact thing happened with my friend who is now 22 weeks with her first baby. She had 2 additional sacs - both empty - and the doctor said that the pregnancy had probably started out as triplets but that only one of the embryos had actually established and continued to grow.

Her doctor said it is very common for a woman to have more than one egg fertilize but that in most cases the pregnancy continues as a singleton only. She told my friend that the empty sacs would just disappear through time (which they did) and that they posed no danger to her baby.

More discussions about sac
References in periodicals archive ?
To gain a better understanding of particle behaviors at different sizes, temporal variation of DFs was quantified in each section of the alveolar sacs (i.e., alveolar duct, four alveoli, and interalveolar pores, Figures 7(b)-7(d)).
The effects of gravity orientation angle on particle deposition in the alveolar sacs are shown in Figure 8.
Figure 9(b) shows the temporal and spatial variation of DFs in the alveolar sacs for breath-holding of 4 seconds.
When there was no septal wall, the alveolar sacs behave more like a single alveolus, as in Talaat and Xi [15], where particle deposition concentrated at the bottom of the alveolus (Figures 11(b) and 11(e)).
Complex flow fields are observed as the inhaled airflow enters the alveolar sacs sequentially from top to bottom and from central to peripheral.
Second, self-similarities exist of particle dynamics in different generations of alveolar sacs. Particles in the central alveoli are more likely to deposit via convective impaction or interception, whereas particles in the peripheral alveoli will deposit via sedimentation, where the flow is slower.
More importantly, well-defined shape and size allowed controlled parametric studies and hence identification of major factors that dictate airflow and particle deposition in alveolar sacs. The second physiological parameter to be improved is the breathing profile, which can have different waveforms and inhalation: exhalation (I: E) ratios.
This finding also provides a fine-tuned molecular mechanism underlying the interaction and communication between epithelial cells and macrophages for maintaining an immune homeostasis of microenvironment alveolar sac in response to Mtb infections.