Body OrganizationChapter 7.1

How Is Your Body Organized??

• Cells• What are Cells?• Basic unit of structure and function in a living thing• What are the main structures of cells?• The cell membrane (outside border of a cell), nucleus (directs

cell’s activities), cytoplasm (jellylike substance that holds all other organelles)

• What is the function of cells?• Carry on processes that keep organisms alive. They grow,

reproduce and get rid of waste

• Tissues• What is tissue?• Group of cells that perform the same function.• Types of tissue:• Muscle tissue- made of muscle cells, allow movement• Nervous tissue- directs and controls movement• Connective tissue- provides support for your body and

connects its parts• Epithelial tissue- protects the delicate structures below it

• Organs• What are organs?• Made up of layers of tissues• Organs perform specific jobs.

• Systems• What is a system?• Made of several organs working together to carry out a

function

• Organism• What is an organism?• When all systems work together, an organism is created.

System Interactions

• How do you move???•Muscles and bones work together, making

your body move. The nervous system tells your muscles when to act.•Muscles and Bones: Skeletal muscles attach

to the bones of your skeleton and provide the force that moves your bones. • Contraction- muscle shortens and pulls the

bones attached• Relaxation- muscle lengthens

• Bones and joints: Your skeleton can bend at your joints (place where two bones come together).

Try This!!! 1. Stand up!2. Stand on one leg and bend the other

leg at the knee.3. Hold that position- which muscles do

you feel?? What is that muscle doing?4. Now straighten your bent leg- what do

you feel your muscle do now??

Which Systems Move Material in Your Body?• The circulatory, respiratory, digestive, and excretory

systems all work together to move materials in your body.

• Circulatory System: Blood that flows towards your heart is oxygen-rich (Veins). Blood that flows away from your heart is oxygen-depleted (Arteries). Capillaries are tiny vessels that carry blood to/away from veins and arteries.

• Blood also contains water, cellular food, carbon dioxide and waste.

• Respiratory System: Did you know that you breath in and out MORE than 20,000 times in ONE day??? We don’t think about it because it is an INVOLUNTARY reaction caused by our nervous system.• When you breathe in, that breath of air goes into your

lungs. Oxygen moves from the air in your lungs into your bloodstream. That oxygen is then delivered to all of your cells through the circulatory system. Carbon dioxide and oxygen are exchanged. The waste product carbon dioxide is now carried BACK to your lungs, where you breathe it out. • That is exhausting just reading it! But your body does

that MORE than 20,000 times in one day!

• Digestive System: Your digestive system helps to break down food into sugars and other nutrient molecules that your cells can use. The circulatory system delivers those nutrients to the cells.• Excretory System: It eliminates wastes

from your body. Cellular waste is passed into the blood. The kidneys then filter the blood. This process produces urine and solid waste. YUCK!

Which Systems Control Body Functions?• To function correctly, each part of your body must be able to

communicate with other parts of your body!• The nervous system and endocrine system work together to

control body functions.• Nervous system: Your senses pick up signals (stimuli) and carry

the information to your brain. A response is what the body does in reaction to that stimulus. • Ex: Your nose smells a cookie (stimulus).

Message is sent to your brain. Your muscular and skeletal system reach for the

cookie (response). Your digestive system releases saliva before the cookie

even reaches your mouth (response).

• Endocrine System: the endocrine system releases chemicals called hormones. The circulatory system transports hormones through the body. Hormones help control every other system.

• Think!!!Q. How are the nervous system and endocrine system different?A. Nervous system carries information through nerve cells, but

the endocrine system releases chemical signals into the blood.Q. Describe an example of a stimulus and response that involves

your sense of hearing.