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Academia - Collins Scientific Pocket Dictionaries - Biology
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osmotic pressure
expression f osmotique

Osmosis pressure. Osmosis can be determined using an osmometer.

Final level.
the tube .
Initial level.
water
Sugar solution.
Dialysis bag.

Water moves into the dialysis bag by osmosis, raising the fluid level in the tube. The pressure exerted by the osmotic movement of water is called osmotic pressure and it depends on the relative concentration of the solute in the solutions. The osmotic pressure that a solution can achieve is called osmotic potential, and can only be detected by an osmotic pressure meter. See turgor and wall pressure.


ossicles
ossicules fpl

The great ones. A series of three fine bones in the middle ear of mammals. See ear.


oval window
fenêtre f oval

Oval window. A membrane that separates the middle and inner ears in mammals. See ear.


ovary
ovaire m

ovary. 1 - A hollow area in the carpel of a flower containing one or more ovule. See -ferti lization in plants.

2- A reproductive organ in female animals.
Vertebrates have two ovaries that produce eggs and release specific sex hormones. See fertiliza ovulation and tion in humans


oviduct
oviducte m

Ovarian duct. trumpet. A tube in animals that transports eggs from the ovaries. In mammals, there are two tubes that lead to the uterus, and fertilization occurs within the oviduct.
See ferti- lization in humans


ovulation
ovulation f

Ovulation. The release of an ovum from a mature Graafian follicle to the surface of the ovary of a vertebrate animal, and from there the egg passes into the oviduct and then to the uterus.

Ovulation in human females: Ovulation is subject to the control of hormones released by the pituitary gland, and the succession of events in female reproductive behavior is called the menstrual cycle. Follicular stimulating hormone (FSH) stimulates the maturation of eggs and causes the ovaries to produce
Estrogen (androgenic) oestrogen. Luteinizing hormone (LH) triggers ovulation and causes the ovaries to release progesterone.

If the mature egg is not fertilized, it is expelled along with the new lining of the uterus and some blood through the vagina, a process called menstruation. The diagram shows the main features of the human menstrual cycle:
See fertilization in humans.

ovule
ovule m

With an egg. A brown seed in flowering plants that develops into a seed after fertilization
See fertilization in plants and carpel.


ovum
ovule m. oeuf m

an egg. Gamete is an unfertilized female produced in the ovary of many animals, and contains a haploid nucleus.
See meiosis, fertilization, and ovulation.


oxygen debt
Dette f d'oxygène

Oxygen debt. A deficiency in oxygen occurs in aerobes when they operate under an insufficient supply of oxygen. An example of this in mammals is muscle action when the supply of oxygen is not sufficient to meet the demand for energy. When this happens, the cells produce energy through lactic respiration, which gives anaerobic respiration acid as a byproduct.

The accumulation of lactic acid leads to muscle fatigue, but it eventually decreases when oxygen intake returns to normal after a period of work. This short-term lack of oxygen must be compensated for by increasing its intake (panting). The figure below shows the effect of muscle work on the concentration of lactic acid.

Concentration of lactic acid in the blood
Normal level
Normal level
Oxygen debt period and business debt repayment

. see respiration