### body part | organ | gill:

Fish gill
* Some fish gills absorb oxygen.
* are efficient organs for gas exchange because they a. have a small surface area
  - made of a delicate tissue with many fine filaments that maximize surface area
  - remarkable things, but the conditions under which they function are pretty specific
* function as both respiratory and excretory organs.
* remove oxygen through a process known as counter current exchange.
* take oxygen from the water as it passes over the gills.

Internal gill
* are formed, opening to the outside by a single hole, the spiracle, on the left side.
* increase surface area with a lesser chance for damage than the external gills.

### body part | organ | gland:

Accessory gland
* Most accessory glands produce chemicals
  - secretion
  - substances
* Most accessory glands serve different functions
* Some accessory glands add secretion
  - undergo development
* participate in normal reproductive function.
* secrete materials.
* undergo a similar development, but at a more even rate and are less precocious.

### body part | organ | gland:

Adrenal gland
* Most adrenal glands have compartments.
* Some adrenal glands are near kidneys.
* Some adrenal glands produce adrenaline
  - cortisol
  - hormone cortisol
  - much cortisol
* are a pair of ductless glands located above the kidneys
  - atop each kidney and produce hormones and biochemicals
  - endocrine glands
* are part of a complex hormone production system, known as the endocrine system
  - endocrine systems
* produce necessary hormones and some steroids.
* release cortisol.
* secrete hormones.
* sit atop the kidneys.

Anal gland
* Most anal glands produce odor.
* Some anal glands contain chemicals
  - look like testes
* Some anal glands produce musks
  - smell musks
  - secrete musky fluid
* are small sacs located on each side of the anus.
* emit a foul-smelling substance used during fights
  - smell secretion
* provide clues to sexual status and perhaps other information as well.
* secrete substances.

Different gland
* produce hormones which affect the function of many organs and systems.
* secrete different pheromones which affect a number of behaviors.

Digestive gland
* Most digestive glands have functions
  - produce enzymes
* open into stomachs.
* secrete enzymes
  - their fluids better and the bowels move more easily

### body part | organ | gland:

Endocrine
* disrupting chemicals damage reproductive organs and cause learning disabilities.
* disrupting chemicals have great potential to cause a lot of concern to the public
  - the potential to alter or mimic hormones
* disrupting chemicals interfere with normal hormone system functions
  - the activity of hormones within the body
  - violate a basic assumption of toxicology and modern risk assessment
* means something that is made by cells and released 'into' the blood or tissue.
* signaling refers to the secretion of a molecule into general circulation.
+ Hormone: Endocrinology
  * Endocrine means something that is made by cells and released 'into' the blood or tissue. So 'endocrine glands' form hormones and release them into the blood or tissue. The opposite word is exocrine and means released 'outside' of the body. An example of 'exocrine' is sweat glands or saliva glands. When people say endocrine they usually mean 'glands that make hormones'.