F214 1.1 - Communication

Question 1

Cell signalling

Answer 1

Communication between cells that allows effective coordination of a response. Uses cell surface molecules (receptors and antigens) and chemical molecules.

Question 2

Receptor

Answer 2

Specialised cells that detect a particular type of stimulus. Can be a single cell or a group of receptor cells ( a sense organ).

Question 3

Chemoreceptor

Answer 3

Specialised cells that detect chemicals e.g. carbon dioxide, taste, smell.

Question 4

Ectotherm

Answer 4

Animal that derives most of its body heat from its environment and regulates its body temperature by its behaviour.

Question 5

Endotherm

Answer 5

Animal that generates most of its body heat internally & controls its body temperature by regulating production & loss of this heat energy. It does this by physiological & behavioural means. Birds and mammals only.

Question 6

Effector

Answer 6

An organ that carries out an action in response to a stimulus, such as a muscle that contracts or a gland that secretes a substance.

Question 7

Homeostasis

Answer 7

Maintenance of a stable internal environment despite external changes.

Question 8

Hypothalamus

Answer 8

Small part of the brain which contains receptors involved in temperature regulation and osmoregulation: it is closely associated with the pituitary gland & controls the secretion of hormones from that gland.

Question 9

Negative feedback

Answer 9

A mechanism by which a change in a parameter is detected and which brings about a response that moves the parameter back towards the norm. It is essential for homeostasis.

Question 10

Positive feedback

Answer 10

A mechanism by which a change in a parameter is detected and which brings about an action that takes the parameter even further away from the norm. It is not a homeostatic mechanism.

Question 11

Response

Answer 11

The reaction to a stimulus; may be a change in behaviour or physiology.

Question 12

Stimulus

Answer 12

Any change in the environment of an organism that causes a response.

Question 13

Thermoregulation

Answer 13

A system by which body temperature is controlled in animals. Animals vary in the extent to which they can do this and in the methods used.

Question 14

Vasoconstriction

Answer 14

The contraction of the smooth muscle in the walls of the arterioles supplying blood to the capillaries near the surface of the skin, narrowing the lumen and reducing the blood flow.

Question 15

Vasodilation

Answer 15

The relaxation of the smooth muscle in the walls of arterioles supplying blood to capillaries near the surface of the skin, widening the lumen and increasing blood flow.