3.1 Animal Cells and Tissues Cardiac cells

Review… just a little In single-celled organisms (like bacteria), the cell has to be able to do everything that is needed to survive In single-celled organisms (like bacteria), the cell has to be able to do everything that is needed to survive In multicellular organisms (like humans), the tasks needed for the organism to survive is done by groups of specialized cells called tissues that perform a similar function In multicellular organisms (like humans), the tasks needed for the organism to survive is done by groups of specialized cells called tissues that perform a similar function – –there are 75 – 100 trillion cells in the human body, all with specific functions Cells  Tissues  Organs  System

Types of Animal Tissues Although there are millions of different animals on Earth, all have the same 4 types of tissues: Although there are millions of different animals on Earth, all have the same 4 types of tissues: 1. Epithelial 2. Muscle 3. Nervous 4. Connective

Epithelial Tissue Line the surfaces of the body Line the surfaces of the body –body covering (exterior) –between organs (interior) Made of cells with strong connections, which form a barrier Made of cells with strong connections, which form a barrier Types: Types:  skin –thin, flat cells that form sheets –act as a semi-permeable barrier to the environment  columnar –columns of cells that line the stomach, intestines, etc.

SKIN COLUMNAR

Muscle Tissue Moves parts of the body Moves parts of the body –achieved by contracting or relaxing bundles of muscle cells Types: Types:  skeletal –cells line up in the same direction, giving a striated (striped) look –attaches to bone –found in limbs and where body needs support  smooth –cells are tapered (thinned out) at both ends –found in blood vessels, walls of inside organs like the esophagus, stomach, …  cardiac –found only in the heart –unevenly striped –contract all at the same time

Nervous Tissue Co-ordinates movement to keep the body functioning properly Co-ordinates movement to keep the body functioning properly –have finger-like projections that receive & transfer signals Cells that make up nervous tissue are called neurons Cells that make up nervous tissue are called neurons Types are varied: Types are varied:  some relay signals from the brain  others detect info from their environment and trigger the body’s responses (e.g., remove hand from a hot object)

Connective Tissue Strengthens, supports, protects, and connects tissues Strengthens, supports, protects, and connects tissues Cells are in a matrix that ranges from a liquid to elastic materials to mineral deposits Cells are in a matrix that ranges from a liquid to elastic materials to mineral deposits Many types, here are some: Many types, here are some:  bone –cells are surrounded by calcium-hardened tissue –needed for support & protection  fat (aka adipose tissue) –made of large, tightly-packed cells –needed for energy storage, padding, and insulation  blood –includes RBCs, WBCs, platelets, & plasma –transports nutrients, including O 2 –clots when skin is cut –attacks invaders like bacteria & viruses

Random Diddies About the Human Body The largest cell in the human body is the female egg and the smallest is the male sperm. Go figure! The largest cell in the human body is the female egg and the smallest is the male sperm. Go figure! A full bladder is roughly the size of a soft ball A full bladder is roughly the size of a soft ball It takes food seven seconds to get from your mouth to your stomach It takes food seven seconds to get from your mouth to your stomach A woman’s heart beats faster than a man’s A woman’s heart beats faster than a man’s Side by side, 2000 cells from the human body could cover about one square inch Side by side, 2000 cells from the human body could cover about one square inch There are about one trillion bacteria on each of your feet There are about one trillion bacteria on each of your feet It takes twice as long to lose new muscle if you stop working out than it did to gain it It takes twice as long to lose new muscle if you stop working out than it did to gain it Your ears secrete more earwax when you are afraid (stressed) than when you aren’t Your ears secrete more earwax when you are afraid (stressed) than when you aren’t If the average male never shaved, his beard would be 13 feet long when he died If the average male never shaved, his beard would be 13 feet long when he died Your body uses 300 muscles to balance itself when you’re standing still Your body uses 300 muscles to balance itself when you’re standing still