Chapter two - From One To Five Trillion Flashcards
What does a human begin as?
All humans began as a single cell. That cell was a fertilised egg. That single cell divide into two cells, then four cells, then eight, and so on…
How many cells?
Despite having millions of cells in your body, there are only about 230 different cell types. Their different shapes and structures give them different properties so they can carry out different functions.
E.g red blood cells and white blood cells, nerve cells, and a group of muscle cells.
What is the nucleus of a cell?
The nucleus is the control center of a cell. It contains the cell’s hereditary information (DNA) and controls the cell’s growth and reproduction.
The nucleus also controls the synthesis of ribosomes and proteins in the cytoplasm.
What is the cytoplasm of a cell?
The cytoplasm consists of all of the contents outside of the nucleus and enclosed within the cell membrane of a cell. This includes the cytosol and in euckaryotic cells, organelles such as mitochondria and ribosomes. Also located within the cytoplasm is the cytoskeleton, a network of fibers that help the cell maintain its shape and give it support.
The cytoplasm is clear in color and has a gel-like appearance.
It is composed mainly of water and also contains enzymes, salts, organelles, and various organic molecules. The cytoplasm helps to move materials around the cell and also dissolves cellular waste.
What is a cell membrane?
The cell membrane (plasma membrane) is a thin semi-permeable membrane that surrounds the cytoplasm of a cell. Its function is to protect the integrity of the interior of the cell by allowing certain substances into the cell, while keeping other substances out. It also serves as a base of attachment for the cytoskeleton in some organisms and the cell wall in others. Thus the cell membrane also serves to help support the cell and help maintain its shape.
What are tissues?
Different types of tissues come together to make organs. Your bones, your heart, you kidneys are all organs. A heart contains muscle tissue, nerve tissue and connective tissue. Sometimes there is more than one type of cell in a tissue. E.g blood is a tissue made up of white blood cells, red blood cells and platelet.
What are organs?
An organ is a collection of tissues joined in a structural unit to serve a common function. Two or more organs working together in the execution of a specific body function form an organ system. Organ systems carry out functions which keep the organism alive.
What are the different organ systems in a human body?
Cardiovascular system: pumping and channeling blood to and from the body and lungs with heart, blood and blood vessels.
Digestive system: digestion and processing food with salivary glands, esophagus, stomach, liver, gallbladder, pancreas, intestines, colon, rectum and anus.
Endocrine system: communication within the body using hormones made by endocrine glands such as the hypothalamus, pituitary gland, pineal body or pineal gland, thyroid, parathyroids and adrenals, i.e., adrenal glands.
Excretory system: kidneys, ureters, bladder and urethra involved in fluid balance, electrolyte balance and excretion of urine.
Immune System: structures involved in the transfer of lymph between tissues and the blood stream, the lymph and the nodes and vessels that transport it including the Immune system: defending against disease-causing agents with leukocytes, tonsils, adenoids, thymus and spleen.
Integumentary system: skin, hair and nails.
Muscular system: movement with muscles.
Nervous system: collecting, transferring and processing information with brain, spinal cord and nerves.
Reproductive system: the sex organs, such as ovaries, fallopian tubes, uterus, vagina, mammary glands, testes, vas deferens, seminal vesicles, prostate and penis.
Respiratory system: the organs used for breathing, the pharynx, larynx, trachea, bronchi, lungs and diaphragm.
Skeletal system: structural support and protection with bones, cartilage, ligaments and tendons.
What are the three main parts of a cell?
- Nucleus
- Cell Membrane
- Cytoplasm
What are cells?
Cells are the basic building blocks of all living things. They provide structure for an organism, take in nutrients from food, convert those nutrients into energy, and carry out specialized functions.
