Essay on Assignment: Heart and Body

Submitted By jessharris98
Words: 2553
Pages: 11

P1) Components of a cell –
There are many different parts to a cell. There is a nucleus which is a small circle and contains genetic information including DNA. It also contains what happens in the cell. The cell also contains a plasma membrane which is the outside of the cell. It is made up of a Hydrophilic (which attracts water) and Hydrophobic structure (which repels water) and allows things in and out of the cell. Next, there is the mitochondrion which is where the chemical reactions take place. There are also two types of endoplasmic reticulum (ER): smooth and rough. The smooth ER acts as a storage organelle for lipids and steroids. The rough has ribosomes attached to it making it rough. The ribosomes are where the proteins are produced and the Golgi apparatus give proteins an outer coating. Lastly, there are Lysosomes which are bubbles that travel in and out of the cell.
Different cells –
Ova and Spermatozoa cells: There are lots of different types of cells. Firstly there is the Ova (egg) cell which is a round cell that contains 23 chromosomes. The cell is round and the biggest cell in the human body. The Ova meets with the Spermatozoa (sperm) cell which makes a total of 46 chromosomes. These are both used in sexual reproduction. The spermatozoa cell is one of the smallest cells and has a tail for mobility.
Epithelial cells: There are 3 different parts to an epithelial cell: cuboidal, columnar and ciliated. The cuboidal cells are a hexagonal shape with a square profile and circular nucleus. They line the surface of various organs and glands. The epithelial cells provide a layer of protection and stop invading bacteria and water loss. In the kidneys, the cuboidal cells help to absorb and transport any filtered substances. Columnar cells are longer than wide and are in your body to protect. For example, in the stomach it provides a barrier to stop any bacteria that could be from food or the air. Lastly, the ciliated cells are a rectangular shape with hair-like lumps. The cells get mucus away from the lungs which minimises the risk of infection.
Nerve cells: The nerve cells send information through the central nervous system. Motor neurons send information away from the central nervous system (CNS). Sensory neurons send information toward the CNS. The cells have dendrites which act as receptors.
Muscle Cells: Muscle fibers attach to our bones which help movement in our joints. Also, smooth muscle cells line the inside of our organs and are responsible for contraction, for example, the bladder. Lastly, cardiac muscles are what the heart is made up of. Muscle cells are lengthened, forming long fibers. They have multiple nuclei in each cell. Smooth muscle cells are short and only have one nucleus. Cardiac muscle cells are striated in appearance though they appear less organized into stripes than skeletal muscle cells. These cells may be divided and become branched, forming physical connections with many nearby cells.

P2) Different Tissues –
Tissues are made up of different cells. One type of tissue found in the human body is the epithelial tissue which makes up your body. Simple cuboidal epithelium is found in organs that are specialized for secretion, such as salivary glands and thyroid follicles, and those that are specialized for diffusion, such as the kidney tubules. These large epithelial cells are specialized for absorption, and are usually found in areas where there is wear and tear, such as the digestive tract. Ciliated tissue can be found in the fallopian tubes of women. These are the tubes which connect the ovary (where eggs are kept) to the uterus (where the egg is fertilized). The cilia help move an egg from the ovary into the uterus each month. Nervous tissues are found everywhere in the body and send messages through the dendrites that are attached to their cell. Then there is muscles tissue, there are three types: Stomach, Cardiac and Skeletal. There is also striated and non-striated. Striated produces