Control And Coordination

Question 1

Multicellular organism

Answer 1

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

Question 2

Homeostasis

Answer 2

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

Question 3

stimulus–response model

Answer 3

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

Question 4

Negative feedback

Answer 4

a response that reduces the original stimulus

Question 5

Glucose

Answer 5

a simple carbohydrate and the simplest form of sugar

Question 6

Pancreas

Answer 6

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

Question 7

Insulin

Answer 7

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

Question 8

Glycogen

Answer 8

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

Question 9

Positive feedback

Answer 9

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

Question 10

Oxytocin

Answer 10

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

Question 11

Nervous system

Answer 11

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.

Question 12

Endocrine system

Answer 12

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

Question 13

Signalling molecules

Answer 13

a chemical involved in transmitting information between cells

Question 14

Central nervous system

Answer 14

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

Question 15

Peripheral nervous system (PNS)

Answer 15

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.

Question 16

Sensory neurons

Answer 16

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

Question 17

Motor neurons

Answer 17

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

Question 18

Neurotransmitters

Answer 18

chemical released from the axon terminals into the synapse between your nerve cells (neurons) during a nerve impulse

Question 19

Endocrine glands

Answer 19

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

Question 20

Hormones

Answer 20

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

Question 21

Thermoregulation

Answer 21

the control of body temperature

Question 22

Thermostat

Answer 22

a device that establishes and maintains a desired temperature automatically

Question 23

Sense organs

Answer 23

a specialised structure that detects stimuli (such as light, sound, touch, taste and smell) in your environment

Question 24

Stimuli

Answer 24

changes in the environment that can be detected and responded to

Question 25

Thermorecptors

Answer 25

special cells located in your skin, part of your brain and body core that are sensitive to temperature

Question 26

Mechanoreceptors

Answer 26

special cells within the skin, inner ear and skeletal muscles that are sensitive to touch, pressure and motion, enabling you to balance, hear and sense pressure and movement

Question 27

Chemoreceptors

Answer 27

special cells within a sense organ (especially the nose and tastebuds) that are sensitive to particular chemicals, giving you the sensations of smell and taste

Question 28

Photoreceptors

Answer 28

a receptor cell located in your eye that is stimulated by light, converting it to electrical energy that is sent to the brain, giving you the sensation of light

Question 29

Pain receptors

Answer 29

special cells located throughout the body (except the brain) that send nerve signals to the brain and spinal cord in the presence of damaged or potentially damaged cells, resulting in the sensation of pain

Question 30

Hot thermoreceptors

Answer 30

a type of receptor in your skin that can detect an increase in skin temperature above 37.5°C (normal body temperature)

Question 31

Cold thermoreceptors

Answer 31

a type of receptor in your skin that can detect a decrease in skin temperature below 35.8 °C

Question 32

Olfactory nerve

Answer 32

The nerve that sends signals to the brain from the chemoreceptors in the nose

Question 33

Pupil

Answer 33

a hole through which light enters the eye

Question 34

Iris

Answer 34

coloured part of the eye that opens and closes the pupil to control the amount of light that enters the eye

Question 35

Reflex action

Answer 35

a quick response to a stimulus. Reflex actions do not involve thought.

Question 36

Cornea

Answer 36

the curved, clear outer covering of your eye

Question 37

Lens

Answer 37

a transparent curved object that bends light towards or away from a point called the focus. The eye has a jelly-like lens

Question 38

Retina

Answer 38

curved surface at the back of the eye. It is lined with sight receptors.

Question 39

Short-sightedness

Answer 39

the condition of not being able to see clearly things that are far away

Question 40

Long-sightedness

Answer 40

the condition of not being able to see clearly things that are close

Question 41

Optic nerve

Answer 41

large nerve that sends signals to the brain from the sight receptors in the retina

Question 42

Rods

Answer 42

sensory receptors in the retina that respond to low levels of light and allow you to see in black and white in dim light

Question 43

Cones

Answer 43

sensory receptors in the retina that respond to red, green or blue light. Cones are mainly in the central part of the retina.

Question 44

Colour blindness

Answer 44

an inherited condition, more common in males, in which a deficiency of one or more of the different types of cones may mean that you find it difficult to see a particular colour or combinations of colours

Question 45

Ear canal

Answer 45

the tube that leads from the outside of the ear to the eardrum

Question 46

Eardrum

Answer 46

a thin piece of stretched skin inside the ear that vibrates when sound waves reach it

Question 47

Ossicles

Answer 47

a set of three tiny bones that send vibrations from the eardrum to the inner ear. They also make the vibrations larger.

Question 48

Middle ear

Answer 48

the section of the ear between your eardrum and the inner ear, containing the ossicles

Question 49

Cochlea

Answer 49

the snail-shaped part of the inner ear. It is lined with tiny hairs that are vibrated by sound and stimulate the hearing receptors.

Question 50

Auditory nerve

Answer 50

a large nerve that sends signals to the brain from the hearing receptors in the cochlea

Question 51

Tongue

Answer 51

the sense organ responsible for taste

Question 52

Tastebuds

Answer 52

nerve endings located in your tongue that contain receptors sensitive to sweet, salty, bitter, sour and savoury chemicals, allowing you to experience taste

Question 53

Papilla

Answer 53

bumps on your tongue that are thought to contain tastebuds