Coordination and response

Homeostasis

The maintenance of a constant internal environment

water regulation

Maintaining a constant internal water concentration

Diuretics

Drugs that elevate the rate of bodily urine excretion (pee more)

ADH

antidiuretic hormone, stop you losing water in urine (pee less)

kidney

organ that filters waste from the blood like urea, water, salt and proteins.

thermal regulation

Body temperature control. Too cold = shiver, vasoconstriction, goose bumps. Too hot = sweat, vasodilatation

vasoconstriction

the constriction of blood vessels, moves blood away from the skin

vasodilation

widening of blood vessels, moves blood to the skin so heat is lost.

nervous system

the body's fast communication network. Made up of nerves.

endocrine system

the body's slow chemical communication system. Glands secrete hormones into the bloodstream

endocrine glands

organs that make hormones, adrenal gland, testicles, ovaries, pituitary, pancreas)

Adrenaline

A hormone that gives the body extra energy

Insulin

A hormone produced by the pancreas, lowers blood sugar levels

CNS (central nervous system)

brain and spinal cord. Linked to the sense organs by nerves.

Neurotransmitters

Chemicals that transmit information from one neuron to another

simple reflex arc

receptor cell sends a message to the sensory nerve, this talks to the motor nerve, this tells a effector organ (muscle/gland) to respond

eye focusing on far objects

cillary muscles contract, suspensory ligaments relax, lens becomes fat

eye focusing on near objects

cillary muscles relax, suspensory ligaments pull the lens, lens becomes flat

eye accommodation

the process by which the eye's lens changes shape to focus near or far objects on the retina

Eye in dim light

radial muscles contract, circular muscles relax. Pupil dilates (gets big)

Eye in bright light

radial muscles relax, circular muscles contract. Pupil contracts (gets small)

Fovea

the central focal point in the retina, around which the eye's cones cluster

optic nerve

the nerve that carries messages from the eye. Creates a blind spot in eye sight

Retina

the light-sensitive inner surface of the eye, containing the receptor rods and cones

Rods

Retinal receptor cells that detect black, white, and gray

Cones

retinal receptor cells that detect colour (red, green, blue)

short-sighted

unable to see far

near-sighted

unable to see distant objects clearly

Cornea

The clear tissue that covers the front of the eye. It bends light

Refraction

Bending of light

blush

skin becomes red because there is lots of blood in it

Arterioles

smallest arteries, small tubes that carry blood

Iris

Colored part of the eye (brown, green, blue)

Nerves

bundle of neurons, like electrical cords that carry messages around the body

H2O

water

Osmoregulation

The control of water in the body

Hypothalamus

part of the brain that monitors body water levels.

Testosterone

Male sex hormone

Oestrogen

Female sex hormone

target organ

a specific organ a hormone acts on

Organisms

living things

Environment

the surroundings and conditions in which a organism lives.

Homeostasis

Maintenance of a constant internal environment, examples are body water content, body temperature

Stimulus

any change in environment (light, gravity, water) that causes a response

Geotropism

A plant's response to gravity

Phototropism

A plant's response to light

Roots

Absorbs water and minerals from the ground. Anchors plant in ground.

Stem

Supporting structure that connects roots and leaves. It carries water & nutrients between them

Auxin

Plant growth hormone

Elongating

Growing longer

positive phototropism

growth of a plant toward light

Plant shoot

The growing stems & leaves

Negative phototropism

Growth away from light

Hormone

Chemical messengers, they are produced in one tissue but affect another tissue

Diffuse

Molecules go from a area of high concentration to a area of low concentration until equilibrium.

control group

In an experiment, the group that is not exposed to the treatment

Independent variable

Variable that is manipulated

Dependent variable

The measurable effect, outcome, or response in which the research is interested.

Germination

Early growth stage of a plant embryo

Horticulture

The growing of fruits, vegetables, and flowers.

Agriculture

farming

Where is ADH produced?

hypothalamus / pituitary

Describe the effects of ADH in the body

1. collecting duct;

2. more permeable / eq;

3. (more) water (re)absorbed (into blood) /

blood more dilute / eq;

4. osmosis;

5. urine concentrated / less water in urine / less urine;

Describe two ways in which nervous communication differs from hormonal communication

1. fast(er) (versus slow(er));

2. electrical/impulse (versus chemical); 3. neurones (versus blood);

4. short(er) lasting (versus long(er) lasting);

5. target cells (versus all around body)

Plant roots also respond to external stimuli.

Describe the response of roots to gravity and explain how this response benefits the plant.

down / positively geotropic / toward gravity / eq;

anchor / hold plant / stability / eq; (obtain) water / mineral ions / nutrients / eq;

A characteristic shown by animals is the ability to respond to their surroundings. For example, a person may withdraw their hand from a hot object.

Describe the sequence of events that cause this response.

receptor / nerve ending;

sensory neurone / sensory nerve; impulse / message / signal;

CNS / spinal cord / grey matter; synapse;

relay neurone / relay nerve; motor neurone ;

muscle / effector;

contract;

Explain what is meant by the term hormone (2)

released from gland / endocrine;

travels in blood;

to target (cells/organs) / eq;

effect / response / coordination / controls / causes change / eq;

Like humans, parakeets need to keep their body temperature constant. Suggest how the volume of oxygen used by a parakeet at rest would change if it was moved to a colder environment

increase (volume of oxygen) / (more) respiration

heat loss