sac

(redirected from alveolar s's)
Also found in: Dictionary, Thesaurus, Encyclopedia, Wikipedia.

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

(sak) a pouch or bag.
air sacs  alveolar s's.
allantoic sac  the dilated portion of the allantois, becoming a part of the placenta in many mammals; it becomes the urachus in humans.
alveolar sacs  the spaces into which the alveolar ducts open distally, and with which the alveoli communicate.
Enlarge picture
Alveolar sacs (sacculi alveolares).
amniotic sac  that formed by the amnion, containing the amniotic fluid.
chorionic sac  that formed by the vertebrate chorion, surrounding the embryo, amniotic cavity, and amniotic sac and contributing to the fetal part of the placenta.
conjunctival sac  the potential space, lined by conjunctiva, between the eyelids and eyeball.
dental sac  the dense fibrous layer of mesenchyme surrounding the enamel organ and dental papilla.
endolymphatic sac  the blind, flattened cerebral end of the endolymphatic duct.
gestational sac  that comprising the extraembryonic membranes that envelop the embryo or fetus; in humans, that formed by the fused amnion and chorion.
heart sac  pericardium.
hernial sac  the peritoneal pouch enclosing a hernia.
Hilton's sac  laryngeal saccule.
lacrimal sac  the dilated upper end of the nasolacrimal duct.
yolk sac  the extraembryonic membrane that connects with the midgut; at the end of the fourth week of development it expands into a pear-shaped vesicle (umbilical vesicle) connected to the body of the embryo by a long narrow tube (yolk stalk) . In mammals, it produces a complete vitelline circulation in the early embryo and then undergoes regression.

sac

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

sac

[sak]
Etymology: Gk, sakkos, sack
a pouch or a baglike organ, such as the abdominal sac of the embryo that develops into the abdominal cavity.

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

cyst; capsule

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]

SAC

Scottish Agricultural College.

SAC Veterinary Science Division Reports
SAC Veterinary Science Division Reports monthly reports of major diseases encountered in the 8 veterinary diagnostic laboratories in Scotland; reported in the Veterinary Record.

sac

a pouch; a baglike organ or structure. See also conjunctival sac.

air sac
1. alveolar sac.
2. one of the large air-filled diverticula of the respiratory system of birds. See also air sacs.
allantoic sac
alveolar s's
the spaces into which the alveolar ducts open distally, and with which the alveoli communicate.
anal sac
endolymphatic sac
the blind, flattened cerebral end of the endolymphatic duct.
heart sac
the pericardium.
hernial sac
the peritoneal pouch that encloses a herniated viscus or mesentery.
lacrimal sac
see lacrimal sac.
paranal sac
pleural sac
the pleura-lined cavity which contains the lung.
ruminal sac
one of the dorsal and ventral sacs of the rumen which are themselves further subdivided to create a caudodorsal sac and a caudoventral sac.
yolk sac
the extraembryonic membrane connected with the midgut; in vertebrates other than true mammals, it contains a yolk mass. See also yolk sac.

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