Grade 9 Biology Practice Flashcards

A set of vocabulary-style flashcards based on the Grade 9 Biology transcript, covering human physiology, health, and environmental science.

Biology

A branch of natural sciences that discusses living organisms, derived from the Greek words 'Bios' meaning life and 'Logos' meaning science.

Digestion

The process of breaking down large food molecules inside the digestive system in the presence of water and enzymes.

Peristalsis

Non-voluntary wave-like movements of the circular muscles of the esophagus that push food into the stomach.

Enzymes

Biological catalysts, such as amylase and pepsin, that assist in the chemical breakdown of food molecules.

Villi

Small finger-like protrusions on the inner wall of the small intestine that increase the surface area for food absorption.

Appendicitis

Inflammation of the appendix caused by bacteria multiplying inside, leading to swelling and severe pain.

Larynx

Known as the voice box, it contains two muscle membranes called vocal cords that vibrate to produce sound.

Alveoli

Microscopic air sacs in the lungs where gas exchange occurs between air and blood capillaries.

Hemoglobin

The protein in red blood cells that transports the majority of oxygen to the body's cells.

Common Cold

A respiratory illness caused by a virus that is transmitted through saliva and nasal secretions during coughing or sneezing.

Plasma

The straw-colored liquid portion of blood that makes up $55\%$ of its volume and contains dissolved nutrients, proteins, and hormones.

Erythrocytes

Red blood cells responsible for transporting oxygen; they are produced in the bone marrow and have a lifespan of approximately $120$ days.

Leucocytes

White blood cells that function in the body's defense against pathogens and typically number between $7,000$ and $10,000$ per milliliter of blood.

Thrombocytes

Also known as blood platelets, these irregular, nucleus-free cell fragments are essential for blood clotting.

Arteries

Thick-walled blood vessels that carry blood (usually oxygenated) away from the heart to various parts of the body.

Pericardium

A two-layered thin membrane filled with fluid that surrounds and protects the heart from friction.

Pulse

The rhythmic expansion and contraction of an artery, typically felt at the wrist, which reflects the heart's beat.

Nephron

The microscopic structural and filtering unit of the kidney; each kidney contains about $1,000,000$ of these units.

Dialysis

A medical procedure using an artificial kidney machine to filter waste materials from the blood when the kidneys fail.

Osteoblasts

Specially named bone cells that, along with minerals and organic materials, make up bone tissue.

Ligament

A strong strand of connective tissue that connects bones at a movable joint to keep them in place.

Synovial Fluid

A lubricating liquid found in movable joints that reduces friction between two adjacent bones.

Skeletal Muscle

Striated muscle tissue that is mostly under voluntary control and works in pairs to move the skeleton.

Neuron

The structural and functional unit of the nervous system, composed of a cell body, dendrites, and an axon.

Myelin

A protein and fat sheath that covers many axons of nerve cells to facilitate signal transmission.

Synapse

The small space between the axon of one neuron and the dendrite of another through which chemical messages are transmitted.

Cerebrum

The largest part of the brain responsible for higher functions like learning, memory, and voluntary movement.

Cerebellum

The part of the brain located under the cerebrum that coordinates movement and regulates balance.

Retina

The innermost, light-sensitive layer of the eye containing cone and rod cells that capture images.

Hormone

A chemical substance produced by endocrine glands that is secreted directly into the blood to regulate specific cellular activities.

Insulin

A hormone produced by the pancreas that regulates blood sugar levels by lowering glucose through storage as glycogen.

Thyroxin

A hormone secreted by the thyroid gland that controls the speed of metabolism and release of energy from food.

Sperm

The male reproductive cell consisting of a head (containing the nucleus), a body (laden with mitochondria), and a tail.

Zygote

The single cell formed by the union of a sperm nucleus and an egg nucleus during fertilization.

Embryo

The developmental stage of a fertilized egg starting from about the eleventh day after fertilization when it implants in the uterus.

Placenta

A specialized organ that allows for the exchange of oxygen, nutrients, and waste products between the mother's blood and the fetus.

Pollution

An unwanted change in the environment that leads to a decrease in environmental quality and harms living organisms.

Recycling

A method of protecting resources by processing used materials like paper, plastic, and metal into new products.