- Mitochondria are known as the powerhouses of the cell.
- They are organelles that act like a digestive system which takes in nutrients, breaks them down, and creates energy rich molecules for the cell.
- Mitochondria are a part of eukaryotic cells.
- The main job of mitochondria is to perform cellular respiration.
- This means it takes in nutrients from the cell, breaks it down, and turns it into energy.
- This energy is then in turn used by the cell to carry out various functions.
- Lysosomes are specialized vesicles within cells that digest large molecules through the use of hydrolytic enzymes.
- A simple description of lysosomes is that they are tiny sacs filled with fluid containing enzymes.
- Which enable the cell to process its nutrients and are also responsible for destroying the cell after it has died.
- Lysosomes are only found in animal cells; a human cell contains around 300 of them.
- Not only do they digest large molecules, they are also responsible for breaking down and getting rid of waste products of the cell
- Lysosomes digest many complex molecules such as carbohydrates, lipids, proteins, and nucleic acids, which the cell then recycles for other uses.
- The pH of lysosomes is acidic (around pH 5) because their hydrolytic enzymes function best at this pH instead of at the neutral pH of the rest of the cell.
- Cytoplasm consists of all of the contents outside of the nucleus and enclosed within the cell membrane of a cell. It is clear in color and has a gel-like appearance.
- Cytoplasm is composed mainly of water but also contains enzymes, salts, organelles, and various organic molecules.
- The cytoplasm functions to support and suspend organelles and cellular molecules. Many cellular processes also occur in the cytoplasm.
- Some of these functions include protein synthesis, the first stage of cellular respiration (known as glycolysis), mitosis, and meiosis.
- In addition, the cytoplasm helps to move materials, such as hormones, around the cell and also dissolves cellular waste.
- The endoplasmic reticulum (ER) is an important organelle in eukaryotic cells.
- It plays a major role in the production, processing, and transport of proteins and lipids.
- The rough endoplasmic reticulum manufactures membranes and secretory proteins.
- The ribosomes attached to the rough ER synthesize proteins by the process of translation.
- The smooth ER has a wide range of functions including carbohydrate and lipid synthesis.
- Lipids such as phospholipids and cholesterol are necessary for the construction of cell membranes.
- The outermost layer of the skin is composed of epithelial tissue and is known as the epidermis.
- It contains squamous cells or keratinocytes, which synthesize a tough protein called keratin.
- Keratin is a major component of skin, hair, and nails.
- Keratinocytes on the surface of the epidermis are dead and are continually shed and replaced by cells from beneath.
- The layer beneath the epidermis is the dermis.
- This is the thickest layer of skin composing almost 90 percent of its thickness. Fibroblasts are the main cell type found in the dermis.
- The dermis also contains specialized cells that help regulate temperature, fight infection, store water, and supply blood and nutrients to the skin.
SENSATION OF SKIN:
- Sensations on the skin are detected by cutaneous receptors. These receptors may feel sensations such as pain, tickle, cold, hot, soft, and rough.
- Mechanoreceptors detect light pressure (e.g., caress), vibration, and texture, nociceptors detect strong pressure (e.g., pain), and thermoreceptors detect temperature.
CATHERINE SHALINI RAJA
CARDIO RESPIRATORY PHYSICAL THERAPIST
FITNESS & SPORTS REHABILITATION SPECIALIST.