3.1 & 3.2 Animal Structure & Stem Cells PDF

3.1 Hierarchy of Structure in Animals From a Single Cell to an Organism Multicellular Organisms Made up of many different specialized cells Specialized animal cells cannot survive on their own and work as part of a much larger group of cells that make up the body of an organism La...

3.1 Hierarchy of Structure in Animals From a Single Cell to an Organism Multicellular Organisms Made up of many different specialized cells Specialized animal cells cannot survive on their own and work as part of a much larger group of cells that make up the body of an organism Large animals may be made up of trillions of individual cells Complexity in Animals: Examples A simple sponge A more complex vertebrate (has a backbone) Hierarchy of Animals Cells are organized in a hierarchy an arrangement or classification of things in order of increasing complexity The functioning of organisms depends on the hierarchy of organization within an animal Hierarchy in Animals: Example Cell (heart muscle cell) Tissue (heart muscle tissue) Organ (heart) Organ system (circulatory system) Organism (human) Organ System Contain one or more organs and structures that work together to perform a vital life function Example: Digestive system Circulatory system Respiratory system Organ Made up of two or more types of tissue that work together to perform a complex life function Example: Heart Lungs Stomach Tissue A collection of similar cells that perform a particular, but limited, function Example: Epithelial tissue Connective tissue Muscle tissue Nerve tissue Tissue: Epithelial EXAMPLE DESCRIPTION y FUNCTION y Lining of digestive Tissue: Connective EXAMPLE DESCRIPTION FUNCTION and fibres held together Tendons by a liquid solid or gel Fills empty space Tissue: Muscle EXAMPLE DESCRIPTION FUNCTION Allows for movement Smooth (e.g. surround Contain specialized Tissue: Nerve EXAMPLE DESCRIPTION FUNCTION p y Nerves in sensory organs (communication within 3.2 Stem Cells and Cell Differentiation Making All the Types of Cells Cellular Differentiation Cellular differentiation: The process that produces specialized cells to perform a specific function Differentiation is directed by the DNA inside each cell and is passed from parent to offspring Stem Cells Stem cell: a cell that can differentiate into many different cell types; an undifferentiated cell Fig. 1 (pg. 77) Stem Cells: Types Embryonic Stem Cells: are pluripotent; they can differentiate into all types of cells in the body Tissue (Adult) Stem Cells: are multipotent; they exist within specialized tissue and can only differentiate into certain types of cells Stem Cells: Sources Embryonic stem cells come from embryos Can become a variety of tissue cells but do not have the ability to produce an entire human being Stem Cells: Sources Tissue (adult) stem cells are found in differentiated tissues throughout the body e.g. stem cells from bone marrow can become red blood cells, white blood cells, or platelets e.g. umbilical cord stem cells can become any kind of blood cell and often stored for use later in life to treat childhood cancers like leukemia Regeneration or Repair In complex animal cells: Certain tissues have the ability to repair or regenerate themselves after *severed “arm” of a being damaged; e.g. starfish regrows muscle, skin, bone Other tissues do NOT have the ability to repair or regenerate; e.g. nerve HOMEWORK: Read pg. 73-76 in textbook; do Q: #2, 5, 6 (pg. 76) Read pg. 77-79 in textbook; do Q: #1, 2, 6 (pg. 79) ANSWERS Q: # 2, 5, 6 (pg. 76) 2. (a) The brain is an organ that is part of only one organ system—the nervous system. (b) The lungs play a role in more than one organ system—the respiratory system and the circulatory system. 5. The well-known organ systems of most animals are very efficient, so different animals tend to have the same systems that are modified for their own needs. 6. Single-celled organisms only have one cell, so cells cannot specialize for different tasks. ANSWERS Q: # 1, 2, 6 (pg. 79) 1. Cellular differentiation means stem cells can grow into specialized cells, such as liver cells or heart cells. 2. Embryonic cells come from an embryo in the earliest stage of cell division and have the potential to become any kind of cell. Tissue stem cells are limited in what they can become. 6. Regeneration allows the animal to replace damaged or diseased body parts.