Year 9 Biological Sciences - Topic 1

A set of vocabulary flashcards covering the levels of biological organisation and the function and types of sensory receptors in the human body.

Cells

The basic unit of life that performs specialised roles, such as skin, muscle, nerves, blood, and bone.

Tissues

Cells of the same kind grouped together, such as connective, epithelial, muscle, and nervous tissues.

Organs

Tissues of different types grouped together to carry out specialised roles within the organism, such as the heart, brain, liver, or pancreas.

Organ systems

Organs of different kinds working together to form specialised body systems, such as the circulatory, nervous, or digestive systems.

Organism

The total of all organ systems working together to maintain the life of the individual, such as animals, plants, or fungi.

Cellular Requirements

The needs of a cell including delivery and removal of gases ($O_2$ and $CO_2$), nutrients, vitamins and minerals ($Vit\text{ A, B, C, D, E, K}$ and $Na^+$, $K^+$, $Mg^{2+}$, $Fe$), waste removal, pH, and water.

Stimuli

Environmental conditions that the body must respond to, including light, sound, touch, taste, and smell.

Receptors

Specialised cells within sense organs that have a specific shape designed to respond to a specific stimulus.

Thermoreceptors

Receptors that detect variations in the temperature of internal and external environments; located in the hypothalamus, spinal cord, abdomen, and skin.

Mechanoreceptors

Receptors that detect touch, pressure, sound, motion, and muscle movement; located in the skin, skeletal muscle, and inner ear.

Chemoreceptors

Receptors that detect changes in particular chemicals such as odours, foods, drinks, pH, and gases in the blood.

Photoreceptors

Receptors that detect changes in light and the colour of light; located in the eyes.

Pain receptors (nociceptors)

Free nerve endings located throughout the body that detect intense stimuli and chemicals released by damaged or inflamed cells.

Hot Thermoreceptors

Receptors in the skin that detect an increase in skin temperature above $37.5$$\text{\degree C}$ .

Cold Thermoreceptors

Receptors in the skin that detect a decrease in skin temperature below $35.8$ $\text{\degree C}$ .

Cilia

Hair-like structures of nasal chemoreceptors that are stimulated when molecules dissolve in the mucus of the nasal cavity.

Olfactory nerve

The nerve that sends messages from the nasal chemoreceptors to the brain to interpret the sensation of smell.

Papillae

Bumps across the tongue that contain taste buds.

Taste Categories

The five categories into which taste can be classified: sweet, salty, sour, bitter, and umami (savoury).

Retina

The area at the back of the eye where images are formed and photoreceptors are located.

Rods

Type of photoreceptors in the retina that detect light intensity (light/dark).

Cones

Type of photoreceptors in the retina that detect colour.

Ossicles

Three tiny bones in the middle ear that receive vibrations from the eardrum and pass them to the inner ear.

Cochlea

The snail-shaped part of the inner ear containing thousands of tiny hairs attached to nerve cells that detect vibration.

Auditory nerve

The nerve that sends messages from the cochlea to the brain to be interpreted as sound.