Cell Physiology PDF

İPEK Nurdan Dikmen, MD Cell Physiology  HUMAN PHYSIOLOGY Introduction working definition of physiology:- Physiology is the study of the function of organisms as integrated systems of molecules, cells, tissues, and organs, in health and disease.  Physiology is...

İPEK Nurdan Dikmen, MD Cell Physiology  HUMAN PHYSIOLOGY Introduction working definition of physiology:- Physiology is the study of the function of organisms as integrated systems of molecules, cells, tissues, and organs, in health and disease.  Physiology is one of the cornerstones of medicine. Physiology is the study of how the body works Cellular physiology is the study of the cellular components that primarily determines organ function. Systems physiology is the study of the coordinated and Loading… networked processes that determine whole body function and adaption to change. 0  study of cell is called Cytology Cell represents the basic unit of life. Human body develops from a single cell called the Zygote ( ovum + spermatozoa). Loading… Zygote undergoes multiplication giving trillion (75-I00 trillions) of cells. 0  Cells are grouped A tissue (e.g. blood, muscle and bone) Organs (e.g. heart , stomach and brain) System (e.g. digestive system) 0 Levels of Structural Organization Smooth muscle cell Molecule 2Cellular level s Cells are made up of Atom molecules s 1Chemical level Atoms combine to Smooth form molecules muscle tissue Heart 3 Tissue level Cardiovascular Tissues consist of system Blood similar types of cells vessels Epithelial tissue Smooth Blood muscle vessel tissue (organ) 6Organismal level Connective The human organism is tissue made up of many organ systems 4Organ level Organs are made up of 5 Organ system level different types of tissues Organ systems consist of different organs that work together closely  cells size, shape and structure Cells are smallest units of the body are microscopic, ranging from l0- 30 Micrometer in diameter. The largest cell is ovum, approximately 500 Micrometer in diameter, and visible to the naked eye.. the smallest cell is the erythrocyte (RBC) of blood about 7.2 -7.5 Micrometer in diameter. The longest cell is the neuron (neur=nerve) up to about 1- meter in length. 0  Different types of cells in human body Like nerve cell, muscle cell, bone cell, gland cells, blood cells , and reproductive cells. Each type adapted to perform one particular function. e.g. the red blood cells transport oxygen from the lung to the tissues. Almost all cells have the ability to reproduce and regenerate when destroyed EXCEPT neurons that present inside the CNS 0  Cell is the structural and functional unit of human body. Each cell is formed from: 1. Cell body Loading… 2. Cell membrane The cell membrane separates the cell body from the fluid surrounding the cell 0 MICROSCOPIC EXAMINATION OF HUMAN CELL  The basic parts of the cell are:. Nucleus.. Cytosol.. Organelles.. Cell membrane. 0  In center of the cell. Nucleus Spherical or oval in shape. Its average diameter is about 5 microns. Nucleus is present only in those cells which divide and produce enzymes. Cells with nucleus are called Eukaryotes (e.g.WBC). Cells without nucleus are called Prokaryotes (e.g. RBC). 0 0  Nucleoplasm Gel fluid within the nucleus. Contains the genetic material DNA which makes up the genes. DNA appears in form of thread like material known as chromatin (means color). Just before cell division, the Chromatin becomes tightly coiled as short, rod like structures called Chromosomes. 0  Number of chromosome is 46 except mature sex cells is only 23 chromosomes. Each chromosome consists of (DNA + protein ). Chromosomes carry the Genetic information about 1. Hereditary 2. Individual characteristics of the person. DNA is responsible for the formation of ribonucleic acid (RNA). RNA regulates the synthesis of proteins by ribosomes. 0  The RNA is synthesized from DNA by transcription The RNA diffuses to the cytoplasm to be translated into proteins (in the ribosomes of the rough ER) The proteins may act within cell or may be packed within vesicles (in Golgi apparatus) for secretion to the outside. 0 0  Functions of the nucleus 1. Controls all activities of the cell. 2. Sends genetic information in form of RNA to the cytoplasm for the synthesis of specific protein. 3. The genes present in the nucleus control the cell division. 0  Nucleolus Small structures inside the nucleus , not covered by membrane. Contains RNA and small amount of proteins. This RNA later on forms Subunits of Ribosomes, which are transported to the cytoplasm to form mature - ribosomes which play an essential role in the formation of proteins. 0 0  Cells of human being have over 100,000 gene pairs. It means that as many as 100,000 different protein are formed as enzymes or structural proteins. 0  Cytosol is the liquid matrix of the cell mostly water. Contains salts, dissolved molecules, enzymes, etc. The cell organelles are found within the cytosol. Cytoplasm = Cytosol + organelles (except nucleus). 0 1. Mitochondria. 2. Ribosome. 3. Endoplasmic reticulum. 4. Golgi apparatus. 5. Centerosome 6. Lysosmes. 7. Peroxisomes. 8. Cytoskeleton. 0  The power house of the cells (provide the energy used by the cell to perform its functions) Active cells like muscles contain large number of mitochondria. 0  Each one is surrounded by 2 phospholipids bilayer membrane The inner is folded to produce cristae The inner cavity of the mitochondria (called the matrix) 0  The inner surface of cristae & matrix contain the respiratory enzymes needed for oxidative phosphorylation of glucose to release large amount of energy in form of ATP the mitochondria is called Power-House of the cell. Loading… 0  Network of tubules with a membrane continuous with that of the nucleus. Types: 1. Rough endoplasmic reticulum. 2. Smooth endoplasmic reticulum. 0  Rough ER: Contains ribosomes. For protein synthesis Smooth ER: NO RIBOSOMES. 0  Ribosomes are made in nucleolus, then leave nucleus and enter cytoplasm. They are the site of protein synthesis. Some are free, but others attach to the endoplasmic reticulum, producing the rough endoplasmic reticulum, RER. 0  Made up of lipid membranes Has no ribosomes. Functions: 1. Makes Lipids (cell membranes lipids & steroid hormones). 2. Detoxifies Drugs. 0  present in all the cells expect red blood cells. Finishes proteins: 1. Adds sugar molecules to side groups. 2. Packages proteins into vesicles for secretion or internal use. Act as quality Control unit in the cell  The proteins synthesized in ER transported to Golgi apparatus, then it will: 1. Processed and packed in the form of secretory-granules 2. Converted into modified compounds like lipoproteins and glycoproteins 3. Transported to the surrounding tissue fluid via the process of exocytosis. 0 0  Produced by the Golgi apparatus. Small vesicles surrounded by membranes. Contain digestive enzymes that break down proteins, lipids, etc. 0  Lysosomes are responsible for the removal of unwanted substances like bacteria and toxins out of the cell. For Example: WBCs contain great number of lysosomes. When a bacteria or foreign particle enters the cell, the lysosomes of WBCs are ruptured and the digestive enzymes are released into the cytoplasm. These enzymes immediately digest the bacteria or the foreign particles. 0  Protein filaments That support the cell membrane from the inside. Form a meshwork of fibers that: 1. Give the cell shape 2. Involved in movement of the whole cell. 3. Transport structures within the cell. 0  Separates the Cytoplasm from the extracellular fluid. Made up of:- phospholipids (25%) Protein (50%) Cholesterol (13%) CHO (3%) & other lipids  The phospholipids have hydrophilic part (phosphate) facing out side & the hydrophobic parts (fatty acids) in the interior of the membrane Thickness = 7.5 nm Its semi-permeable membrane Allows passage of lipid soluble substances & prevents passage of water soluble substances 0  Functions of the cell membrane 1. Support the cell. 2. Envelope the cell 3. Selective barrier 4. Keep the negative charge of the cell. 5. Transport 6. Communications 7. Recognition  Cell membrane contains 2 types of protein: Peripheral proteins: Attached to one surface of the cell membrane (usually the inner surface) Integral proteins: Extends throughout the cell membrane 0. Act as ions channels. Act as enzymes. Act as receptors. Act as antigen (glycoprotein). Acts as cell adhesion molecules. Structural supports to the membrane  Carbohydrate on the surface of a cell membrane are either attached to proteins (forming glycoprotein) or to lipids (forming glycolipids)  Nerve cells: Specialized for transmitting electrical impulses Red blood cells: Specialized for carrying O2 to the tissues. 0