Lesson 9.1 (TEKS 7.13A)

The student is expected to identify and model the main functions of the systems of the human organism, including the circulatory, respiratory, skeletal, muscular, digestive, urinary, reproductive, integumentary, nervous, immune, and endocrine systems;

Homeostasis

an organism’s ability to maintain steady internal conditions when outside conditions change.

digestive system

the group of organs that work together to break down foods into substances that your cells can use.

enzyme

protein that speeds up chemical reactions.

nutrient

a part of food used by the body to grow and survive.

urinary system

the body organs that filter your blood, removing waste and excess water.

respiratory system

the organs that supply your blood with oxygen.

circulatory system

the group of organs and tissues that carry needed materials to cells and remove their waste products.

immune system

a combination of body defenses made up of the cells, tissues, and organs that fight pathogens in the body.

pathogen

an agent that causes disease.

integumentary system

the organ system consisting of the skin, hair, nails, and exocrine glands.