Unit 3 : Cells and Tissues
Here is a list of all the important cell organelles that are in all animal cells .
Cell membrane - forms the outer covering of the cell, and is semi-permeable.
Cytoplasm - is a gel-like matrix where all the other cell organelles are suspended inside the cell.
Nucleus - contains the hereditary material DNA and directs the activities of the cell.
Centrioles - organize the microtubules assembly during cell division.
Endoplasmic Reticulum - are a network of membranes composed of rough and smooth endoplasmic reticulum.
Golgi complex - is responsible for storing, packaging of cellular products.
Lysosomes - are enzyme sacs, that digest cellular wastes.
Microtubules - are hollow rods, function primarily as support and shape to the cell.
Mitochondria - is the site for cellular respiration and producers of energy.
Ribosomes - are made of RNA and proteins, and are sites for protein synthesis.
Nucleolus - is the structure within the nucleus and helps in synthesis of ribosomes.
Nucleopore - is the tiny hole in the nuclear membrane, allows the movement of nucleic acids and proteins in/out of the cell.
Cell membrane - forms the outer covering of the cell, and is semi-permeable.
Cytoplasm - is a gel-like matrix where all the other cell organelles are suspended inside the cell.
Nucleus - contains the hereditary material DNA and directs the activities of the cell.
Centrioles - organize the microtubules assembly during cell division.
Endoplasmic Reticulum - are a network of membranes composed of rough and smooth endoplasmic reticulum.
Golgi complex - is responsible for storing, packaging of cellular products.
Lysosomes - are enzyme sacs, that digest cellular wastes.
Microtubules - are hollow rods, function primarily as support and shape to the cell.
Mitochondria - is the site for cellular respiration and producers of energy.
Ribosomes - are made of RNA and proteins, and are sites for protein synthesis.
Nucleolus - is the structure within the nucleus and helps in synthesis of ribosomes.
Nucleopore - is the tiny hole in the nuclear membrane, allows the movement of nucleic acids and proteins in/out of the cell.
Cells are a very important to the human body. Without certain cells in our body, it wouldn't survive! To give a some specific examples of cells and their importance, I'm going to give a description of three cells. A Red Blood Cell, Cone Cells and a white Blood Cell.
Red blood cells play an important role in your health by carrying fresh oxygen throughout the body. The oxygen gives your blood its bright red color.
Red blood cells are round with a flattish, indented center, like doughnuts without a hole. Your health care provider can check on the size, shape, and health of your red blood cells using tests, such as the complete blood count screening.
Hemoglobin is the protein inside red blood cells that carries oxygen. Red blood cells also remove carbon dioxide from your body, transporting it to the lungs for you to exhale.
Red blood cells are made inside your bones, in the bone marrow. They typically live for about 120 days, and then they die.
Red blood cells are made inside your bones, in the bone marrow. They typically live for about 120 days, and then they die.
Cone cells are one of the two types of photoreceptor cells that are in the retina of the eye which are responsible for color vision as well as eye color sensitivity; they function best in relatively bright light, as opposed to rod cells that work better in dim light. Cone cells are densely packed in the fovea centralis.
Cones are less sensitive to light than the rod cells in the retina (which support vision at low light levels), but allow the perception of color. They are also able to perceive finer detail and more rapid changes in images, because their response times to stimuli are faster than those of rods.
White blood cells are the cells of the immune system that are involved in protecting the body against both infectious disease and foreign invaders.
All leukocytes are produced and derived from a multipotent cell in the bone marrow known as a hematopoietic stem cell. Leukocytes are found throughout the body, including the blood and lymphatic system.
There are four categories of tissues in the human body: epithelial, connective, nervous, and muscle. Epithelial tissue protects your body from moisture loss, bacteria, and internal injury. There are two kinds of epithelial tissues:
Nervous tissue consists of two kinds of nerve cells:
- Covering and lining epithelium covers or lines almost all of your internal and external body surfaces; for example, the outermost layer of your skin and other organs, and the internal surface lining of your lymph vessels and digestive tract.
- Glandular epithelium secretes hormones or other products such as stomach acid, sweat, saliva, and milk.
- Loose connective tissue holds structures together. For example, loose connective tissue holds the outer layer of skin to the underlying muscle tissue. This tissue is also found in your fat layers, lymph nodes, and red bone marrow.
- Fibrous connective tissue also holds body parts together, but its structure is a bit more rigid than loose connective tissue. Fibrous connective tissue is found in ligaments, tendons, cartilage, and bone.
Nervous tissue consists of two kinds of nerve cells:
- Neurons are the basic structural unit of the nervous system. Each cell consists of the cell body, dendrites, and axon.
- Neuroglia, or glial cells, provide support functions for the neurons, such as insulation or anchoring neurons to blood vessels.
- Skeletal muscle is attached to bones and causes movements of the body.
- Cardiac muscle is found in the heart.
- Smooth muscle lines the walls of blood vessels and certain organs such as the digestive and urogenital tracts.