Occipital
/ɒkˈsɪpɪtəl/
Relating to the back of the head or the skull.
Oculomotor Nerve
/ˌɒkjʊloʊˈmoʊtər nɜːrv/
The third cranial nerve, which controls most of the eye's movements and the constriction of the pupil.
Olfactory
/ɒlˈfæktəri/
Relating to the sense of smell.
Oocyte
/ˈoʊəsaɪt/
A cell in an ovary which may undergo meiotic division to form an ovum.
Oogenesis
/ˌoʊəˈdʒɛnɪsɪs/
The production or development of an ovum.
Organelle
/ˌɔːrɡəˈnɛl/
Any of a number of organized or specialized structures within a living cell.
Origin
/ˈɒrɪdʒɪn/
The attachment of a muscle tendon to a stationary bone.
Osmoreceptor
/ˌɒzmoʊrɪˈsɛptər/
A sensory receptor primarily found in the hypothalamus that detects changes in osmotic pressure.
Osmosis
/ɒzˈmoʊsɪs/
The process by which molecules of a solvent pass through a semipermeable membrane from a less concentrated solution into a more concentrated one.
Ossification
/ˌɒsɪfɪˈkeɪʃən/
The natural process of bone formation.
Osteoblast
/ˈɒstioʊˌblæst/
A cell that secretes the matrix for bone formation.
Osteoclast
/ˈɒstioʊˌklæst/
A large multinucleate bone cell which absorbs bone tissue during growth and healing.
Osteocyte
/ˈɒstioʊˌsaɪt/
A bone cell, formed when an osteoblast becomes embedded in the matrix it has secreted.
Osteon
/ˈɒstiɒn/
The fundamental functional unit of much compact bone, also known as a Haversian system.
Otolith
/ˈoʊtəlɪθ/
Calcium carbonate structures in the inner ear that help with the sense of balance and gravity.
Ovary
/ˈoʊvəri/
A female reproductive organ in which ova or eggs are produced.
Ovulation
/ˌɒvjʊˈleɪʃən/
The release of an egg from the ovary into the Fallopian tube.
Oxyhemoglobin
/ˌɒksihiməˈɡloʊbɪn/
A bright red substance formed by the combination of hemoglobin with oxygen.
Oxytocin
/ˌɒksɪˈtoʊsɪn/
A hormone released by the pituitary gland that causes increased contraction of the uterus during labor and stimulates the ejection of milk.