Intro to Physiology PDF

**[Introduction]** **[What is Physiology?]** **Physiology is the study of normal body functions** **The study of the normal functions of a living organism and its component parts includes all chemical and physical processes.** **[Systems of Human Body Includes:]** - **Digestive System** -...

**[Introduction]** **[What is Physiology?]** **Physiology is the study of normal body functions** **The study of the normal functions of a living organism and its component parts includes all chemical and physical processes.** **[Systems of Human Body Includes:]** - **Digestive System** - **Respiratory System** - **Urinary System** - **Cardiovascular System** - **Musculoskeletal System** - **Reproductive System** - **Regulatory or controlling systems which include (Endocrine & Nervous)** **[Levels of Organization of the Human Body\ ]Cells \> Tissues \> Organs \> Systems \> Body** **[Organisms]** ------------------------------------------------------------------------------------------------------------------------------ **In uni-cellular organism** **In multi-cellular organisms** ------------------------------------------------------------------------- ---------------------------------------------------- **The cell performs all vital processes\ **Group of cells collect together to form\ needed for life e.g. respiration, digestion, movement & reproduction.** tissues or organs to perform specific functions.** **e.g. Amoeba** **e.g. Humans** ------------------------------------------------------------------------------------------------------------------------------ **\ But still each cell can sustain its own life** **[1)Human Body Cells (Eukaryotic)]** **It is the basic unit of both structure and function** **All cells perform certain basic functions like:** - **Getting nutrients** - **Eliminating wastes** - **Synthesizing cellular component** - **Respond to changes in the environment and reproduce.** **[2)Human Body Tissues]** **Groups of cells of similar specializations\ Primary tissue types:\ 1) Muscle: skeletal, cardiac, and smooth\ 2) Nervous: transmits electrical impulses\ 3) Epithelial: sheets and glands\ 4) Connective: few cells dispersed in an extracellular matrix** **[3)Human Body Organs\ ]2 or more types of tissues organized to form certain function** **e.g. The stomach has four tissues: Epithelial, smooth muscle, nervous, and connective tissue** **[4)Human Body Systems]** - **Collection of organs that perform related function.** - **Body systems maintain homeostasis and maintain a dynamic Steady State in the internal environment.** **[Body composition]\ In adult male, body weight is 70 kilograms** **Percentage to his body weight** - **18 % proteins** - **15 % fats** - **7 % minerals** - **[60 % water]** **[Factors Affecting Total Body Water]** **[Physiological Factors:]** **1)Amount of fat: Water content [decreases] with obesity.\ 2)Sex: Females have lower water content than males.\ 3)Age: Total body water [decreases] with age.** **N.B. Water content decreases with increased fat content, and decreases progressively with age** **[The concentration of water varies from one tissue to another]\ Brain 85%\ Muscle 75%\ Adipose Tissue 20%\ Dentin of teeth 10%** **[Functions of water]** - **Major component of blood plasma** - **Cools the body through sweat secretion** - **Solvent for nutrients and waste products** - **Essential for metabolism** - **Lubricant in joints** - **Provides some minerals** **[Distribution of Body Water (Fluids)]** **1)Intracellular Fluid (ICF) : 2/3 of water inside cells** **2)Extracellular Fluid (ECF) : 1/3 Water outside cells\ It is subdivided to:\ 1)Interstitial fluid (ISF) : 3/4** **\ 2)Plasma : 1/4** A diagram of body water compartment Description automatically generated **Total body water = 60% of body weight = 42 L in a 70 kg person** **[Body Water Compartments]** - **There is continuous exchange between the ICF and ISF through the cell membrane.** - **Also, between ISF and Plasma through the capillaries.** **[Body Water Compartments]** **[Intracellular fluid (ICF)]** **[Extracellular Fluid (ECF)]** --------------------------------------------- ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------------------ **Found inside the cells** **Interstitial fluid (ISF)** **Plasma** **Separated from ECF by plasma membrane** **Part of ECF found outside the vascular system, in the spaces between the cells** **Part of ECF found inside the vascular system, and it is separated from ISF by the walls of capillaries** **Main cation: Potassium** **Main cation: Sodium** **Main anion: Proteins & Phosphate** **Main anion: Chloride** A diagram of a fluid Description automatically generated **[Composition of ICF ]** **ICF Contains [large quantities of K^+^] & small quantities of Na^+^ , the [main cation] in ICF is [Potassium ]** **ICF contains very large amounts of phosphate & proteins & small amount of Cl- , the [main anions] in ICF are [Phosphates and proteins]** **[Composition of ECF]\ ECF Contains large quantities of Na^+^ & small quantities of K+ , the main caution in ECF is Na+** **ECF contains a large amount of CL- & small amount of Phosphate & proteins the main ICF anion is Cl-** **ECF constitutes the Body Internal Environment, and has to be maintained stable (Volume, Composition, PH, Temperature).\ ▪ ECF is in close contact to 4 organs that face the external environment: GIT, Kidneys, Lungs, Skin\ ▪ Any disturbances in these organs may lead to abnormalities in ECF, and diseases** **[Maintenance of Water Balance\ ]** +-----------------------------------+-----------------------------------+ | **Water Gain** | **Water Loss** | +===================================+===================================+ | **Drinking\ | **Urine\ | | Food\ | Sweat and respiration\ | | Metabolism** | Stool** | +-----------------------------------+-----------------------------------+ | **[Under normal body activity and | | | moderate climate]** | | +-----------------------------------+-----------------------------------+ | **Sources of water gain** | **Sources of water loss** | +-----------------------------------+-----------------------------------+ | **Drinking (1300 ml)\ | **Urine (1500 ml)** | | Water contained in solid food | | | (800 ml)\ | **Insensible water loss via | | Water delivered from oxidative | respiratory tract & skin (900 | | metabolism in body (400 ml)** | ml)\ | | | Stool (100 ml)** | +-----------------------------------+-----------------------------------+ | **[Under Pathological | | | Conditions]** | | +-----------------------------------+-----------------------------------+ | **In patient receiving | **Patients have severe vomiting | | intravenous infusion** | and diarrhea** | +-----------------------------------+-----------------------------------+ **Dehydration: patients with severe vomiting and diarrhea (Loss more than gain)** **[Symptoms:]\ Thirst , Dry mouth , Headache , dry skin , Rapid heartbeat , decreased urination** **Overhydration: patients receiving Intra-venous infusions (Gain more than loss)** **[Homeostasis] (Homeo = same / Stasis = staying)** **It is the maintenance of constant conditions in the internal environment of the body** - **The internal environment is the ECF** - **It is essential to maintain constant conditions in this internal environment, since normal cell function depends upon this constancy.** **[The Advantages of Homeostasis\ ]1) Increased chances of survival.\ 2) Allows freedom to live in a variety of conditions.\ 3) Permit proper functioning of the brain.** **Almost all diseases are failures of homeostasis** **[Characteristics of homeostasis]** - **Homeostasis is not rigid, fixed state but a dynamic steady state.** - **Does not mean that ECF composition is absolutely unchanging.** - **Homeostasis is not unlimited** **[Factors in the Internal Environment that must be Homeostatically maintained]** - **pH: 7.4** - **Blood volume: 5 L.** - **Blood pressure: 120/80 mmHg** - **Temperature: 37 ◦C** - **Concentration of nutrients.** - **Concentration of water, salt and other electrolytes.** - **Concentration of waste products.** **For example: If you decide to go for a run, different body organs cooperate\ to maintain homeostasis (stable interna**  **l environment) regarding:** **Components of Homeostatic Control Systems\ [1. Sensor (receptor):]\ Detect the changes in the environment & informs the center.\ [\ 2. Control (center):]\ Generates signals for correction of error.\ ** **[3. Effector (organ):]\ Responds to the center and corrects the error** **[Negative Feedback Loop]\ The response is opposite to the stimulus (disturbance).** **\ Most of controls systems act by this process** A diagram of body parts Description automatically generated **[Positive Feedback Loop]\ The response is in the same direction as the stimulus.\ It leads to instability and [often to death.]\ It represents failure of homeostasis.\ But sometimes, it can be useful: like in uterine contraction and blood clotting**