Human Systems and Homeostasis

humans + other multicellular organisms are a collection of specialized cells. they develop from a single zygote
examples of specialized cells eg. cardiac muscle, skin, liver, neuron, etc.
cells produced during the first few divisions of the zygote are known as embryonic stem cells
these stem cells have the potential to become any type of specialized cell in the body
within a few weeks, a process called determination occurs in which most stem cells
differentiation: process by which committed cells acquire the structures + functions of highly specialized cells
eg. different types of muscle cells, sperm cells, nerves, etc.
programmed cell death (apoptosis) ie. hand/mitten in embryo

cells: all have a particular structure and perform specific tasks
tissues: groups of similar cells that work together to perform a specialized function; the human body is made of four types of tissues
epithelial tissue: lines body cavities + organs eg. skin, membranes that line the respiratory + digestive tracts
muscle tissue: capable of contracting to produce movement
- 3 types: cardiac, skeletal, and smooth
nervous tissue: transmits + receives impulses, processes information, and regulates the body's response to its environment