organ of Giraldés

organ

(or'gan) [L. organum fr Gr. organon, tool, (musical) instrument, (bodily) organ]

A body structure made of several tissues that all contribute to specific functions. Many organs occur in pairs. In such pairs, one organ may be extirpated and the remaining one can perform all necessary functions peculiar to it. One third to two fifths of some organs may be removed without loss of function necessary to support life. See: table

accessory organ

An organ that has a subordinate function.

acoustic organ

See: Corti, Alfonso Giacomo Gaspare

organ of Corti

See: Corti, Alfonso Giacomo Gaspare

enamel organ

A cup-shaped structure that forms on the tooth buds of an embryo. It produces the enamel and serves as a mold for the remainder of the tooth.

end organ

The expanded end of a nerve fiber in a peripheral structure.

excretory organ

An organ that is concerned with the excretion of waste products from the body.

See: excretion

organ of Giraldés

Paradidymis.

Golgi tendon organ

See: Golgi, Camillo

gustatory organ

The organ of taste; a taste bud.

organ of Jacobson

See: Jacobson, Ludwig

lymphatic organ

A structure composed principally of lymphatic tissue. It includes the lymph nodes, spleen, tonsils, and thymus.

lymphoid organs

The spleen, lymph nodes, thymus, Peyer patches, and tonsils, where more than 98% of T lymphocytes are found.

See: T cell

neuromuscular end organ

A spindle-shaped bundle of specialized fibers in which sensory nerve fibers terminate in muscles.

neurotendinous end organ

A specialized tendon fasciculus in which sensory nerve fibers terminate in the tendon. Synonym: tendon spindle

reproductive organ

Any organ concerned with the production of offspring. These include the primary organs (testes and ovaries) and accessory structures (penis and spermatic cord in the male and fallopian tubes, uterus, and vagina in the female).

Synonym: sex organ

organ of Ruffini

See: Ruffini, Angelo

sense organ

A sensory receptor; a structure consisting of specialized sensory nerve endings that are capable of reacting to a stimulus (an external or internal change) by generating nerve impulses that pass through afferent nerves to the central nervous system. These impulses may give rise to sensations or reflexly bring about responses in the body.

sensory end organ

Any of the special clusters of cells that form a capsule around the receptor ends of certain sensory axons and affect the response of the axons. They include Meissner corpuscles, Pacinian corpuscles, Ruffini corpuscles, and Golgi tendon organs.

See: sensory receptor

sex organ

Reproductive organ.

solid organ

An internal organ that has a firm tissue consistency and is neither hollow (such as the organs of the gastrointestinal tract) nor liquid (such as blood). Such organs include the heart, kidney, liver, lungs, and pancreas.

special sense organs

Any of the organs of smell, taste, sight, balance, and hearing.

spiral organ

See: Corti, Alfonso Giacomo Gaspare

target organ

1. An organ upon which a chemical or hormone acts.

2. An organ adversely affected by a disease or condition.

vestigial organ

An organ that is underdeveloped in humans but is fully functional in some animals.

vomeronasal organ

Jacobson organ. See: Jacobson, Ludwig

Weber organ

See: Weber, Moritz I.

organs of Zuckerkandl

See: Zuckerkandl, Emil SOURCE: Adapted from Gray's Anatomy, ed 27. Lea & Febiger, Philadelphia, 1959; Gray's Anatomy, ed 37. Churchill Livingstone, London, 1987; Growth. Federation of American Societies for Experimental Biology, Washington, DC, 1962; Jandl, JH, Blood. Little, Brown and Co., Boston, 1987.

Description	Size	Weight	Capacity
Adrenal gland	5 cm high	5 g
	3 cm across
	1 cm thick
Bladder	12 cm in diameter		500 ml (when moderately full)
Blood volume			? 4–6 L
			? 3–5 L
Brain		? 1240–1680 g
		? 1130–1570 g
Ear, external canal	2.5 cm long (from concha)
Esophagus	23–25 cm
Eye	23.5 mm vertical diameter
	24 mm anteroposterior diameter
Fallopian tube	10 cm
Gallbladder	7–10 cm long		30–50 ml
	3 cm wide
Heart	12 × 8–9 × 6 cm	?280–340 g
		?230–280 g
Intestines—small	Variable
	6–7 m long
Intestines—large	1.5 m long
Intestines—vermiform appendix	2–20 cm long, average 9 cm
Intestines—rectum	12 cm long
Kidney	11 cm long	? 150 g
	6 cm broad	? 135 g
	3 cm thick
Larynx	? 44 × 43 × 36 mm
	? 36 × 41 × 26 mm
Liver		? 1.4–1.8 kg	6500 ml
		? 1.0–2.5 kg
Lung		Right 625 g
		Left 565 g
Ovaries	3 × 1.5 × 1 cm	2–3.5 g
Pancreas	15 cm long	? 74–106 g
		? 70–100 g
Parathyroid	6 × 3–4 × 1–2 mm	50 mg
Pharynx	12.5 cm long
Prostate	2 × 4 × 3 cm	8 g
Skeleton		Average adult male, 4957 g
Skull		Average (without teeth), 642 g	Variable ? 406 ml ? 207 ml
Spinal cord	42–45 cm long	30 g
Spleen	12 × 7 × 3–4 cm	150 g
		80–300 g
		Decreases with age
Stomach	Variable		Variable
	25 cm long		1500 ml
	10 cm wide
Testes	4–5 × 2.5 × 3 cm	10.5–14 g
Thoracic duct	38–45 cm long
Thymus		Newborn, 10.9 g
		10–15 yr, 29.5 g
		20–25 yr, 18.6 g
Thyroid	Each lobe 5 × 3 × 2 cm	30 g total
Trachea	11 cm long
	2–2.5 cm in diameter
Ureter	28–34 cm long
Urethra	? 17.5–20 cm long
	? 4 cm long
Uterus	7.5 × 5.0 × 2.5 cm	30–40 g (nonpregnant)
Vagina	Anterior wall length 7.5 cm
	Posterior wall length 9.0 cm