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Flashcards in Biology Deck (21):
1

Multicellular organism

An organism that is composed of many cells. Most plants and animals are multicellular.

2

Homeostasis

The maintenance of a relatively constant internal physiological environment of the body or part of the body (e.g. blood glucose level, pH, body temperature) in varying external conditions

3

Stimulus-response model

A system in which any changes or variations (stimuli) in the internal environment are detected (by receptors); if a response is required, this is communicated to effectors to bring about some type of change or correction so the conditions can be brought back to normal

4

Negative Feedback

A response that reduces the original stimulus

5

Glucose

A simple carbohydrate and the simplest form of sugar

6

Pancreas

A large gland in the body that produces and secretes the hormone insulin and an important digestive fluid containing enzymes

7

Insulin

Hormone that removes glucose from the blood and stores it as glycogen in the liver and muscles

8

Glycogen

The main storage carbohydrate in animals, converted from glucose by the liver and stored in the liver and muscle tissue

9

Positive Feedback

A reaction in which the response is in the same direction as the stimulus—for example, during childbirth the onset of contractions activates the release of the hormone oxytocin, which stimulates further contractions

10

Oxytocin

Hormone secreted from the pituitary gland that assists in the formation of bonds between mothers and their babies, and perhaps between people in close relationships

11

Nervous System

The system of nerves and nerve centres in an animal in which messages are sent as an electrical and then a chemical impulse. It comprises the central nervous system and the peripheral nervous system.

12

Endocrine System

The body system of glands that produce and secrete hormones into the bloodstream in order to regulate processes in various organs

13

Signalling molecules

A chemical involved in transmitting information between cells

14

Central nervous system

The part of the nervous system composed of the brain and spinal cord

15

Peripheral Nervous System

Made up of sensory and motor neurons. It connects the central nervous system to the rest of the body, and detects and responds to change.

16

Motor Neurons

The nerve cell that causes an organ, such as a muscle or gland, to respond to a stimulus

17

Sensory Neurons

A nerve cell in the sense organs. It detects change in the environment and sends a message to the central nervous system.

18

Endocrine Glands

Organs that produce hormones. Endocrine glands release their hormones into the bloodstream for transport to target organs.

19

Hormones

Chemical substances produced by glands and circulated in the blood. Hormones have specific effects in the body.

20

Thermoregulation

The control of body temperature

21

Thermostat

A device that establishes and maintains a desired temperature automatically