Cells & Tissues (3.1)

Cells 75 to 100 trillion cells in the human body Most cells are specialized to perform specific roles. What causes them to differentiate?

Cell Specialization Factors that affect cell specialization: – cell cytoplasm – environmental conditions – neighbouring cells

Abnormal Development Environmental factors such as exposure to chemicals can cause abnormal cell specialization & development.

Turning on/off genes When cells are specialized, they have certain genes “turned off” and others “turned on”.

Specialized animal cells are organized into tissues, just like plant cells.

Types of Tissues

Epithelial Tissue Strongly connected cells form barriers that line the surfaces of the body. E.g., skin epithelia, columnar epithelia (line the digestive tract & glands)

Muscle Tissue Changes shape by shortening & lengthening. e.g., skeletal muscle, smooth muscle, cardiac muscle

Nervous Tissue Coordinate body actions using cells called neurons. Move information between brain/spinal cord to muscles/glands & detect environmental information.

Connective Tissue Strengthens, supports, protects, and connects cells & tissues. e.g., bone, fat, blood

Organ Donation According to the Trillium Gift of Life Network, there are approximately 1600 Ontarians on transplant waiting lists. Trillium Gift of Life Network

Organs for Transplant

Living Donation Living donation accounted for 255 transplants in Ontario in Because of the long wait lists, sometimes people look for donors on social media, or turn to illegal organ trade themselves…social media themselves