General Physiology Introduction PDF

General Physiology By Dr/ Hanaa Mostapha Badran  Our Agenda Theoretical practical topic 1 General physiology Cell membrane topic 2 Blood components...

General Physiology By Dr/ Hanaa Mostapha Badran  Our Agenda Theoretical practical topic 1 General physiology Cell membrane topic 2 Blood components Transport across cell membrane topic 3 Haemostasis comple blood counts topic 4 Blood group blood group and erythrocyte sedimentation rate topic 5 Nervous system resting membrane potential topic 6 Action potential topic 7 topic 8 Muscle contaction simple muscle twith topic 9 function of autonomic nervous system autonomic ganglia topic10 Autonomic chemical transmitters and receptors Vital signs topic11 regulation of respiration respiratory function tests topic12 Hypoxia and cyanosis What is physiology? Physiology is the study of how living organism’s body work functions of the normal living organs and how these functions interplay to maintain human existence and well being. Physiology is the basis of medicine  Functions of body water 1. It is the origin of life. 2. Media for all biological reactions. 3. Ionization of dissolved salts. 4. It regulates body temperature. 5. It gives the blood its fluidity.  Total body water Total body water TBW = 60% x Body Weight in kilograms Intracellular Fluid (ICF): The amount of water that’s inside our cells accounts for 2/3rds of our TBW. Extracellular Fluid (ECF): The amount of water that surrounds our cells accounts for 1/3 of our TBW. ECF is also known as interstitial fluid because it’s the fluid in between the cells. Tissue fluid: 2/3rd of ECF Blood plasma: 1/3rd of ECF Transcellular fluid: Often not calculated as a fraction of the extracellular fluid, but it is about 2.5% of TBW. Total Blood Volume (TBV) Blood is made up of blood cells and blood plasma. TBV = 8% x Body Weight (kg).  Body fluids There are very important differences between the electrolytes inside and outside the cell ICF ECF K+ Na+ Mg+2 Ca+2 PO4 -3 Cl- Protein – HCO3- (due to negatively charged amino acids in proteins) there’s a high amount of potassium (K+) inside the cell. there’s a high amount of sodium (Na+) outside the cells. The body fluids are solutions of water, dissolved in this water many organic molecules (carbon-containing molecules such as carbohydrates, lipids, proteins, and nucleic acids), as well as inorganic molecules and ions Body fluids  Extravascular body fluids Pleural fluid. Pericardial fluid. Peritoneal fluid (ascites). Amniotic fluid. Cerebrospinal fluid. Semen. Urine. Sputum. Saliva. Nasal secretion. Sweat. Stool. Vaginal secretions. Synovial fluid. Tears. Body fluids Cell  Definition of cell membrane -It is a thin elastic semi-permeable membrane that surrounds the cell. -Semi-permeable means allowing some substances to pass through it and prevent others). -Its thickness is about 7.5 nm. (75 Ao = Angstrom = 10-10 of meter).  Functions of cell membrane It separates the cytoplasm from ECF It maintains cell's internal environment It controls distribution of ions e.g Na+, K+ into and out of the cell. 4-It contains receptors for hormones and transmitter substances It generates membrane potentials.  components of cell membrane : It is formed of 3 components: 1- Lipids 42%. 2- Proteins 55%. 3- Carbohydrates 3%. Membrane phospholipids Hydrophilic heads PO4- Hydrophobic tails F.A  ECF Bilayer Hydrophobic area ICF Cholesterol Transport through cell membrane O2 and nutrients Cell CO2 and wastes  Transport through cell membrane Passive:down its electro- Diffusion chemical gradient. 2- doesn’t need energy. against electro-chemical Active gradient. transport 2- needs energy large sized substance Vesicular transport Resting membrane potential The negative values indicate that the cytosol (intracellular fluid) is more electronegative than the extracellular fluid. The values of EM depend on several factors: Concentration of ions inside and outside the cell. Ions that contribute the most are the sodium, potassium, calcium, and chloride ions. Activity of the sodium-potassium pump. Variable permeability of the cell membrane for ions. Resting membrane potential Resting membrane potential (EM) originates from the different concentrations of ions (expressed in mmol/l) at the inner and outer surface of the cell membrane. There are four excitable tissues in our body, and all of them have different EM values: Skeletal muscle cell= -90 millivolts (mV) Smooth muscle cell = -55mV Cardiac muscle cell = -80mV Neuron= -65mV  Causes of RMP unequal distribution of ions across the cell membrane Selective permeability of the cell membrane Na+ - K+ pump The membrane is impermeable to the intracellular protein anions  Homeostasis Homeostasis is the state of steady internal chemical and physical conditions maintained by living systems.”  Homeostasis is a mechanism that maintains a stable internal environment despite the changes present in the external environment. It is the job of cells, tissues, organs, and organ systems throughout the body to maintain many different variables within narrow ranges that are compatible with life. Keeping a stable internal environment requires continuous monitoring of the internal environment and constantly making adjustments to keep things in balance.The body maintains homeostasis by controlling a host of variables ranging from body temperature, blood pH, blood glucose levels to fluid balance, sodium, potassium and calcium ion concentrations. Component: Receptor Control center effector  Factors affecting homeostasis: Many factors can affect homeostasis. The most common are: Genetics. Physical condition. Diet and nutrition. Venoms and toxins. Psychological health. Side effects of medicines and medical procedures.  Different types of homeostasis: Blood glucose homeostasis. Blood oxygen content homeostasis. Extracellular fluid pH homeostasis. Plasma ionized calcium homeostasis. Arterial blood pressure homeostasis. Core body temperature homeostasis. The volume of body water homeostasis. Extracellular sodium concentration homeostasis. Extracellular potassium concentration homeostasis. Blood partial pressure of oxygen and carbon dioxide homeostasis.  Feedback mechanisms It is a physiological regulatory system that returns the body to a normal internal state (homeostasis) Types of feedback Negative feedback Positive feedback  Main types of feedback : feedback loops into two main types: 1. positive feedback loops, in which a change in a given direction causes additional change in the same direction. 2. negative feedback loops, in which a change in a given direction causes change in the opposite direction.  Types of feedback : positive feedback loops, in which a change in a given direction causes additional change in the same direction. Eg: Normally Prolactin stimulates milk production during pregnancy, progesterone inhibits Prolactin No milk production. At birth Prolactin surges resulting in milk production. As the baby feeds, its suckling stimulates the breast, promoting further release of prolactin, resulting in yet more milk production negative feedback loops, in which a change in a given direction causes change in the opposite direction. For example, For example, pupillary diameter is adjusted to make sure an appropriate amount of light is entering the eye. If the amount of light is too low, the pupil dilates, if it is too high, the pupil constricts. Homeostasis and feedbacks Negative feedback Wrap up organs Organ tissues cells systems tissues Distribution of total body water  Wrap up Cells contains ICF & surrounded by ECF. Total body water 42 L: 28 L (ICF), 14 L (ECF). Homeostasis Types of feedback. Constituents of cell membrane: lipid, protein, carbohydrates  Wrap up cause of RMP: Unequal distribution of ions across cell membrane due to: 1. Membrane selective permeability 2. Na+ -K+ pump 3. impermeability of intracellular protein  MCQ 1. Total body water for 70 kg adult male is? A. 50 L B. 52 L C. 62 L D. 42 L  MCQ 2. intracellular fluid differs from extracellular fluid in: A. It has higher Na level. B. It has higher Cl level C. It has higher K level D. It has higher Ca level.  MCQ 3. When body temperature increase, blood vessels dilate to enhance temperature loss, this is considered: A. Negative feed back B. Positive feed back C. Both A & B D. Neither A or B  MCQ 4. When hormone A increase, it stimulates hormone B release, then hormone B stimulates further release of hormone A. This is considered: A. Negative feed back B. Positive feed back C. Positive followed by negative feed back D. Negative followed by positive feed back  5. Constituents of cell membrane: A.Lipid B. protein C. carbohydrates D.All of the above