Year 8 Science: Plant and Animal Systems

Vocabulary flashcards covering Year 8 Science units on human organ systems, plant organs, circulatory components, blood vessels, respiratory function, skeletal structure, and plant tropisms.

Levels of Organisation

The structural hierarchy in multicellular organisms, ordered as: CELLS \rightarrow TISSUES \rightarrow ORGANS \rightarrow SYSTEMS \rightarrow ORGANISM.

Skeletal System

Provides movement, protects internal organs, provides structure, stores minerals, and makes blood cells.

Muscular System

Consists of skeletal, smooth, and cardiac muscles; it enables movement, pumps blood, and facilitates movement within organ systems.

Integumentary System

Includes skin, hair, and nails; it protects the body and helps regulate temperature.

Nervous System

Consists of the brain, spinal cord, and nerves; it controls and coordinates body activities and responds to stimuli.

Circulatory System

Consists of the heart, blood, and blood vessels; it transports oxygen, nutrients, hormones, and wastes around the body.

Respiratory System

Includes the lungs, trachea, and bronchi; it allows gas exchange by taking oxygen in and removing carbon dioxide out.

Digestive System

Consists of the mouth, oesophagus, stomach, intestines, and liver; it breaks down food and absorbs nutrients into the blood.

Excretory System

Includes the kidneys, bladder, and ureters; it removes waste from the blood and produces urine.

Immune System

Consists of white blood cells and lymph nodes; it defends the body against pathogens and disease.

Endocrine System

Includes the pituitary gland, thyroid, adrenal glands, pancreas, and ovaries/testes; it produces hormones to regulate body processes.

Reproductive System

In females, includes ovaries, uterus, and vagina; in males, includes the penis and testicles; it produces reproductive cells and enables reproduction.

Root System

The plant organ system responsible for absorbing water and nutrients.

Shoot System

The plant organ system responsible for photosynthesis, transport, support, and reproduction.

Roots

Plant organs that absorb water and minerals from the soil.

Stem

A plant organ that supports the plant and transports substances.

Leaves

Plant organs that make food through photosynthesis.

Flowers

Plant organs responsible for reproduction and producing seeds.

Red Blood Cells (RBCs)

Cells shaped as flattened biconcave discs that carry oxygen around the body; they lose their nucleus after formation and are filled with haemoglobin.

Haemoglobin

A special protein on the surface of RBCs that binds to oxygen; each molecule requires $4$ Iron molecules.

White Blood Cells (WBCs)

Cells with a nucleus and organelles like lysosomes that help fight pathogens and disease.

Platelets

Cell fragments that release chemicals to aggregate together and form a mesh called fibrin to create blood clots.

Plasma

A clear, yellowish liquid environment for materials to float in; made of about $90\%$ water and $10\%$ dissolved substances like nutrients, hormones, and waste.

Bone Marrow

Found in the centre of large bones; red marrow produces blood cells, while yellow marrow is mostly fat and contains stem cells.

Leukemia

Cancer that causes the body to make large numbers of abnormal white blood cells and reduces the production of healthy blood cells.

Closed Circulatory System

A system where blood always stays inside blood vessels and does not directly contact body tissues or cells.

Arteries

Blood vessels with thick, muscular, elastic walls that carry blood AWAY from the heart at high pressure.

Veins

Blood vessels with thinner walls and valves that carry blood BACK to the heart at lower pressure.

Valves

Structures in veins and the heart that prevent blood from flowing backwards and ensure it moves in one direction.

Capillaries

Tiny blood vessels with walls only one cell thick; they allow for the diffusion of oxygen, nutrients, and waste between blood and tissues.

Atherosclerosis

A condition where fatty plaques build up inside arteries, which can lead to blocks, heart attacks, or strokes.

Cardiac Muscle

Special Y-shaped muscle cells with striations (elastic fibres) that make up the heart.

Coronary Artery

An artery that delivers oxygenated blood directly to the heart muscle itself.

Double Circulatory System

A system where blood passes through the heart twice during a complete circuit: once to the lungs and once to the rest of the body.

Pulmonary Circuit

The path that transports blood between the heart and lungs for gas exchange.

Systemic Circuit

The path that transports blood between the heart and the rest of the body.

Septum

A wall that separates the two sides of the heart to prevent oxygenated and deoxygenated blood from mixing.

Systolic Pressure

The amount of force on the arteries when the heart is pumping blood (when ventricles contract).

Diastolic Pressure

The amount of force on the arteries when the heart is relaxing and refilling between pumps.

Sinoatrial Node

A bundle of nerves that acts as a pacemaker by sending a consistent signal to the heart muscle to beat.

Antigen

A protein marker on the surface of a red blood cell that identifies the cell as self or non-self.

Antibodies

Immune system 'fighters' in the plasma that attacking any cells with foreign antigens.

Xylem

Vascular tissue with thick side walls that transports water and dissolved nutrients upwards from the roots via capillary action.

Phloem

Vascular tissue with large pores in cell walls that transports sugars (glucose) in both directions; it uses companion cells for energy.

Capillary Action

The movement of water in thin tubes upwards against the force of gravity.

Pharynx

The throat area where the back of the nose and mouth meet.

Alveoli

Small sacs in the lungs with walls one cell thick where gas exchange occurs between air and blood.

Diaphragm

A skeletal muscle sheet that contracts and moves down to allow inhalation, and relaxes and moves up during exhalation.

Tidal Volume

The amount of air regularly breathed in and out during normal breathing.

Vital Capacity

The maximum amount of air that can be exhaled after inhaling as deeply as possible.

Stomata

Pores in plant leaves that open to allow gas exchange (CO2 in, O2 and water vapour out).

Transpiration

The loss of water vapour out of an open stoma of a plant leaf.

Axial Skeleton

Includes the skull, ribs, and vertebrae; its primary purpose is to protect vital internal organs.

Appendicular Skeleton

Includes arm, leg, shoulder, and hip bones; it is primarily used for movement.

Spongy Bone

Porous bone fibres with air spaces that keep bones lightweight while providing protection.

Compact Bone

Solid bone on the outer surface that provides strength to resist breaking.

Antagonist Pairs

Pairs of muscles, such as the biceps and triceps, that work opposite one another to produce movement.

Ligaments

Tough fibres that connect bone to bone.

Tendons

Elastic fibres that connect muscle to bone.

Synovial Fluid

A lubricant in joints that reduces friction and provides nutrients.

Tropism

The purposeful growth of a plant towards or away from an environmental stimulus.

Phototropism

Plant growth in response to light to increase photosynthesis.

Gravitropism

Plant growth in response to gravity, ensuring roots grow towards soil and stems towards light.

Hydrotropism

Plant growth where roots move towards water sources.

Thigmotropism

Plant growth in response to touch or physical contact.