Body Organization
What are the four levels of organization in the human body?
Cells → tissues → organs → organ systems.
What is the main job of an organ system?
To carry out a major function for the body.
What system breaks down food into nutrients the body can use?
The digestive system.
Which organ pumps blood throughout the body?
The heart.
What system produces chemical messages called hormones?
The endocrine system.
What is the basic unit of structure and function in the human body?
Cells
Which two systems work together to move the body?
The muscular and skeletal systems.
What sugar do cells use for energy?
Glucose.
What gas do you inhale and what gas do you exhale?
You inhale oxygen and exhale carbon dioxide.
What organ is the control center of the nervous system?
The brain.
What is a group of the same type of cells working together called?
A tissue
When you run, which systems work together to deliver oxygen to muscles?
The respiratory system and circulatory system.
Where does most nutrient absorption take place?
In the small intestine.
Which system removes waste from the blood?
The excretory system
What is a hormone?
A chemical signal that helps regulate body processes.
What is the highest level of body organization?
The organism.
What is homeostasis?
Maintaining stable internal conditions in the body.
Which two systems work together to supply energy to cells?
The digestive system and circulatory system.
Where does the exchange of oxygen and carbon dioxide occur?
In the alveoli of the lungs.
What is a stimulus?
Any change or signal from the environment that causes a response.
Give one example of how structure and function are related in the body.
Muscle cells are long and stretchy so they can contract and help the body move.
Explain how the nervous system helps multiple systems interact.
It sends and receives signals that control actions, movement, and responses between different systems.
Why do cells need oxygen to release energy?
Oxygen helps break down glucose in the cells to produce energy (cellular respiration).
How do the circulatory and respiratory systems work together to manage materials?
Respiratory brings in oxygen and removes carbon dioxide. Circulatory transports these gases to and from the cells.
Explain how the nervous and endocrine systems control processes differently.
The nervous system sends fast electrical signals. The endocrine system sends slower chemical signals through hormones.