1.4 Grouping Cells into Tissue
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Similar cells can be grouped together into tissue. Tissue is a group of similar cells that work together to carry out a particular function. We have different subgroups of tissue depending on what the function of the tissue is.
Let’s first look at bone. Bone tissue is a hard substance because it contains calcium salts. The calcium salts allow the bones to resist bending and compression (squashing) forces.
Another type of tissue is muscle. Muscles are comprised of millions of muscle cells. They contract and relax. We have 3 different types of muscle:
Another type of tissue is blood. Blood is made up of red and white blood cells in a liquid matrix called plasma. Red blood cells are used to carry oxygen. White blood cells are used in the immune system and protect against infectious disease and foreign invaders.
Nerve tissue is in the brain, spinal cord and nerves.
Epithelia is another type of tissue (in the singular form it is epithelium). Epithelia tissue forms boundaries between different environments. Nearly all substances must pass through epithelium. There are many different types of epithelia. One type is ciliated. Ciliated epithelium cells have celia on the top of their cells. The celia are like hair and they allow the cell to move material along. Another type of epithelium is squamous epithelium. The lining of the cheek is made out of squamous epithelium.
This section is just a quick introduction into some of the different types of cells and tissue that we will see in the course.
Let’s first look at bone. Bone tissue is a hard substance because it contains calcium salts. The calcium salts allow the bones to resist bending and compression (squashing) forces.
Another type of tissue is muscle. Muscles are comprised of millions of muscle cells. They contract and relax. We have 3 different types of muscle:
- Voluntary muscle cells. Voluntary muscles means that the contraction of the muscle is down to the conscious thought process of the brain. When the brain wants to contract the muscles, the muscles contract. For example, if I want to move my arm, my brain tells the muscle cells in my arm to contract and my arm moves. The word voluntary is used because the brain consciously tells the muscles to contract or relax.
- Involuntary muscle cells. These are muscles that are not under conscious control by your brain. They are located in the walls of hollow visceral organs, except the heart. They are present in the intestine and bladder. Involuntary muscle cells are also known as smooth muscle.
- Cardiac muscle cells. These muscle cells are located in the muscle wall of the heart. They are under involuntary control i.e. the brain does not consciously control them.
Another type of tissue is blood. Blood is made up of red and white blood cells in a liquid matrix called plasma. Red blood cells are used to carry oxygen. White blood cells are used in the immune system and protect against infectious disease and foreign invaders.
Nerve tissue is in the brain, spinal cord and nerves.
Epithelia is another type of tissue (in the singular form it is epithelium). Epithelia tissue forms boundaries between different environments. Nearly all substances must pass through epithelium. There are many different types of epithelia. One type is ciliated. Ciliated epithelium cells have celia on the top of their cells. The celia are like hair and they allow the cell to move material along. Another type of epithelium is squamous epithelium. The lining of the cheek is made out of squamous epithelium.
This section is just a quick introduction into some of the different types of cells and tissue that we will see in the course.