October 2026 TEAS 7 Science Study Guide

Cardiovascular system Blood flows from the body into the right atrium, through the right ventricle to the lungs, back to the left atrium, then out of the left ventricle to the body. The left ventricle is the thickest chamber because it pumps against systemic pressure. Read the full guide Respiratory system Air travels nose to pharynx, larynx, trachea, bronchi, bronchioles and alveoli, where gas exchange happens across a single cell layer. The diaphragm contracts and flattens to draw air in. Read the full guide Nervous system The central nervous system is the brain and spinal cord; the peripheral nervous system is everything else. The peripheral system divides into somatic voluntary control and autonomic involuntary control, which splits again into sympathetic and parasympathetic. Read the full guide Digestive system Mechanical and chemical digestion run from mouth to oesophagus, stomach, small intestine and large intestine. Most absorption of nutrients happens in the small intestine; the large intestine reabsorbs water. Read the full guide Skeletal system Bone supports the body, protects organs, stores calcium and produces blood cells in red marrow. The axial skeleton is skull, spine and ribs; the appendicular skeleton is the limbs and girdles. Read the full guide Muscular system Skeletal muscle is voluntary and striated, cardiac muscle is involuntary and striated, and smooth muscle is involuntary and non-striated. Muscles pull rather than push, so they work in opposing pairs. Read the full guide Endocrine system Glands release hormones into the bloodstream to act on distant targets, which makes endocrine signalling slower and longer-lasting than nervous signalling. The pituitary directs several other glands. Read the full guide Lymphatic and immune system The lymphatic system returns fluid to the bloodstream and filters it through lymph nodes. Immunity is innate and non-specific or adaptive and specific, with the adaptive arm producing memory. Read the full guide Integumentary system Skin, hair and nails form the body's first barrier. Skin also regulates temperature through sweating and vessel dilation, and synthesises vitamin D. Its layers are epidermis, dermis and hypodermis. Read the full guide Urinary system Kidneys filter blood, balance fluid and electrolytes, and produce urine that passes through the ureters to the bladder and out via the urethra. The nephron is the functional unit. Read the full guide Male and female reproductive system Expect structures and their functions, gamete production, and the hormonal control of the menstrual cycle by oestrogen and progesterone. Read the full guide

Cell structure, function and organization Mitochondria produce ATP, ribosomes build proteins, the nucleus holds DNA, and the Golgi packages material for transport. Prokaryotes have no nucleus or membrane-bound organelles; eukaryotes have both. Read the full guide Cell transport Passive transport needs no energy and moves substances down a concentration gradient by diffusion or osmosis. Active transport uses ATP to move them against it. Read the full guide Genetics and DNA DNA is a double helix in which A pairs with T and C with G. Genotype is the genetic makeup, phenotype the observable trait, and alleles can be dominant or recessive. Read the full guide Mendel's law of inheritance Mendel's laws of segregation and independent assortment underpin the Punnett square. A cross of two heterozygotes gives the familiar 3:1 phenotype and 1:2:1 genotype ratios. Read the full guide Structure and function of macromolecules Carbohydrates supply quick energy, lipids store energy and build membranes, proteins do structural and enzymatic work, and nucleic acids carry genetic information. Each is built from its own monomer. Read the full guide Role of microorganisms in disease Bacteria, viruses, fungi and parasites cause disease by different mechanisms, which is why antibiotics treat bacterial infections and do nothing against viruses. Read the full guide

Atomic structure and the periodic table Protons and neutrons sit in the nucleus and electrons orbit it. Atomic number is the proton count and defines the element; mass number is protons plus neutrons. Groups run down the table and periods across. Read the full guide Chemical reactions and chemical bonding Ionic bonds transfer electrons between a metal and a non-metal; covalent bonds share them between non-metals. Balanced equations must carry the same number of each atom on both sides. Read the full guide Acids and bases The pH scale runs 0 to 14, with 7 neutral. Acids donate hydrogen ions and sit below 7; bases accept them and sit above. Each whole step is a tenfold change in concentration. Read the full guide Physical properties and states of matter Solids, liquids and gases differ in particle arrangement and energy. Physical changes such as melting alter form only; chemical changes produce a new substance. Read the full guide

Scientific reasoning This covers experimental design, variables, controls, hypotheses and evaluating evidence. A valid experiment changes one variable at a time and holds the rest constant. Read the full guide