“It is shameful for man to rest in ignorance of the structure of his own body, especially when the knowledge of it mainly conduces to

his welfare, and directs his application of his own powers.”

The Human Body Systems

What are the levels of organization in a multicellular organism?

A. Cells Organ Tissues Organ SystemB. Tissues Cells Organ Organ SystemC. Cells Organ Organ System TissuesD. Cells Tissues Organ Organ System

Cells Tissues Organs Organ System

• Tissues: groups of similar cells that perform a single function, such as connecting a muscle to a bone

• Organ: group of tissues that work together to perform a complex function, such as sight

• Organ System: group of organs that perform closely related functions

Muscle Cells Cardiac Muscle Tissue Heart

Circulatory System

Human

4 Major Types of Tissues in the Body• Epithelial Tissue: includes glands & tissues that cover interior

& exterior body surfaces

• Connective Tissue: provides support for the body & connects its parts

• Nervous Tissue: transmits nerve impulses throughout the body

• Muscle Tissue: along with bones, enables the body to move & move substances through the body

Your skin is a type of:

A. Epithelial TissueB. Connective TissueC. Nervous TissueD. Muscle Tissue

Epithelial Tissue!

Your tongue is a type of:

A. Epithelial TissueB. Connective TissueC. Nervous TissueD. Muscle Tissue

Muscle Tissue!

Your Achilles Tendon is a type of:

A. Epithelial TissueB. Connective TissueC. Nervous TissueD. Muscle Tissue

Connective Tissue!

The Human Body Systems

• Nervous System• Skeletal System• Muscular System• Integumentary System• Digestive System• Excretory System• Respiratory System

• Circulatory System• Endocrine System• Reproductive System• Immune System

All of your body systems work together to keep your body functioning normally.

Homeostasis

• Our body systems work together to help us maintain homeostasis, a stable internal environment.

• Homeostasis is maintained by feedback inhibition, where the result limits the process.

Feedback Inhibition

Think of a thermostat & how it cools the room.

Keeping Blood Sugar Levels Constant

Rise in blood glucose levels above the set point.

Pancreas secretes insulin into the blood.

Glucose is absorbed or stored by the body’s cells, removing it

from the blood.

Blood glucose level returns to set point.

Pancreas stops secreting insulin.

Homeostasis Activity

• How does light affect pupil dilation?• How does exercise affect your pulse?• How does standing on 1 leg affect your

balance?

Before you leave…• Answer the following question at the bottom of your

handout:

Which body system do you think helps your body maintain homeostasis? Defend your answer!