Grade 5 Science: Respiratory, Digestive, and Reproductive Systems

Vocabulary practice flashcards covering key organs, pathways, and functions of the human respiratory, digestive, and reproductive systems for Grade 5 Science.

Respiratory System

The body system involved in breathing that allows air to enter the body, move through breathing passages, reach the lungs, and leave the body again.

Nose

The main entryway for air during normal breathing located on the face, containing tiny hairs and mucus that help trap dust, dirt, and particles while warming incoming air.

Windpipe

Also called the trachea, a tube found between the upper breathing passage and the lungs lined with mucus and tiny hair-like structures that carries air toward and away from the lungs.

Lungs

A pair of soft, spongy organs located inside the chest that receive inhaled air, help the body obtain oxygen, and remove carbon dioxide.

Bronchi

Large tubes connecting to the bottom of the trachea in the chest that divide into smaller branches to carry air deeper into the lungs.

Inhalation

The process of breathing air into the body through the nose and windpipe into the lungs, causing the lungs to expand.

Exhalation

The process of breathing air containing waste carbon dioxide out of the lungs through the breathing passages, causing the lungs to contract or become smaller.

Gas Exchange

The vital process taking place mainly in the tiny air sacs of the lungs where oxygen moves into the blood and carbon dioxide moves out.

Oxygen

A gas needed by the body from inhaled air that passes from the lungs into the blood to be carried to different parts of the body.

Carbon Dioxide

A waste gas produced by the body and brought back by the blood to the lungs to be removed during exhalation.

Diaphragm

A muscle located below the lungs that moves downward during inhalation and upward during exhalation to change available space in the chest.

Simple Lung Model

A simplified representation using a straw as an air passage, inner balloons as lungs, a bottle as chest space, and a bottom rubber membrane to demonstrate lung expansion and contraction.

Inhalation Pathway

The sequential route taken by incoming air during breathing: Nose → Windpipe → Lungs.

Digestive System

A group of connected organs that work together in an organized sequence to process food, break it down, absorb nutrients and water, and remove remaining waste.

Mouth

The beginning of the digestive pathway where food enters, is bitten and ground by teeth, moved by the tongue, and mixed with saliva.

Gullet

Also known as the esophagus, a muscular tube connecting the mouth to the stomach that uses coordinated muscular contractions to move swallowed food downward.

Stomach

A muscular, pouch-like organ that churns food and mixes it with digestive juices to further break it down and soften it.

Small Intestine

A long, narrow, winding tube where digestion continues and most nutrients are absorbed through its walls into the body.

Large Intestine

The digestive organ that receives remaining unabsorbed material, absorbs much of the remaining water, and prepares leftover waste to become more solid for removal.

Saliva

A fluid in the mouth that mixes with chewed food to moisten it and begin the process of digestion.

Teeth

Structures in the mouth responsible for biting, cutting, tearing, and grinding solid food into smaller pieces to make swallowing easier.

Tongue

A muscular organ in the mouth that moves food around, helps mix it with saliva, and assists in pushing food toward the back of the mouth for swallowing.

Digestion

A series of connected processes that break food into smaller pieces, move it along the digestive tract, churn it with digestive juices, and absorb nutrients and water.

Complete Digestive Pathway

The sequential order through which food travels: Mouth → Gullet → Stomach → Small Intestine → Large Intestine.

Scientific Model

A simplified representation—such as drawings, clay, paper, or craft materials—that helps explain body structures, pathways, and relationships that are difficult to observe directly.

Digestive Model Limitations

The principle that craft or paper models cannot perform real biological digestion or absorb actual nutrients, but serve only to illustrate organ order and functions.

Reproductive System

The body system containing specialized male and female organs that work together to produce reproductive cells, enable fertilization, and continue human life.

Ovaries

A pair of small, oval-shaped female reproductive organs located on both sides of the uterus that produce egg cells (ova) and female reproductive hormones.

Uterus

Also called the womb, a hollow, muscular organ located in the pelvic area between the ovaries where a fertilized egg attaches and where an embryo and fetus develop during pregnancy.

Vagina

A muscular canal connecting the lower part of the uterus to the outside of the body that receives sperm during reproduction and serves as part of the birth canal during delivery.

Testis

One of a pair of oval-shaped male reproductive organs (plural: testes) located inside the scrotum that produce sperm cells and male reproductive hormones.

Prostate

A small gland located below the bladder surrounding part of the urethra that produces fluid that becomes part of semen to support and protect sperm cells.

Penis

An external male reproductive organ containing the urethra through which urine leaves the body and through which semen passes out during reproduction.

Scrotum

The external sac-like structure located below the male body that houses and protects the two testes.

Fertilization

The process marking the beginning of human life when a male sperm cell joins with a female egg cell.

Embryo

An early stage of a developing human in the uterus after fertilization occurs.

Fetus

A later stage of a developing human in the uterus before birth, following the embryo stage.

Prenatal Development

The growth and development of a developing baby inside the mother's uterus before birth.

Ova

The female reproductive cells, also commonly called egg cells, produced by the ovaries.

Semen

The fluid containing sperm cells and supporting secretions from the prostate that passes out of the male body through the penis.