Metabolism (the sum of all the chemical processes that occur in the human body

1. Basic Life processes • (certain processes that distinguish organisms (living things) from non-living things • Metabolism (the sum of all the chemical processes that occur in the human body • there are 2 phases catabolism anabolism) • Movement (includes motion of the whole body, individual organs, single cells, and • even tiny structures inside cells) • Responsiveness (body's ability to detect and respond to changes) • Reproduction(formation of new cells for tissue growth, repair or replacement or the production of a new individual) • Growth (increase in body size that results from an increase in size of existing cells,) • Differentiation(development of a cell from an unspecialized to a specialized state)

2. What is Physiology? Physiology: is the study of the functionsof the human body of how the body works, from cell to tissue, tissue to organ, organ to system, and of how the organism as a whole accomplishes particular tasks essential for life. The study of physiology includes study not only of how each of body systems carries out its functions, but also of the mechanisms involved to regulate these activities in order to maintain homeostasis under a variety of conditions (Homeostasis Is the ability of the body to maintain a relatively stable internal environment

3. Levels of Organization

4. Levels of Organization of the Human Body Atoms Molecules 1. The Chemicals 2. The Cell It is the smallest living unit of the human body (the most basic structural and functional unit of organisms) examples - Nerve cells - Blood cells - Muscle cells - Fat cells

5. The Tissue • Tissues are groups of cells, and the surrounding environment, which work together to produce a specific function. • There are only 4 types of tissues in the body: • Epithelial tissue • Connective tissue • Muscle tissue • Nervous tissue

6. The Organ • Organs are structures that are made of two or more different types of tissues. • They have specific functions and a defined shape. • The heart is an example of an organ. • It is made of muscle, as well as connective and nervous tissue. • The tissues work in concert to move blood through the body

7. Organ System Major Functions Protection from environmental hazards; temperature control Integumentary system Support, protection of soft tissues; mineral storage; blood formation Skeletal system Locomotion, support, heat production Muscular system Directing immediate responses to stimuli, usually by coordinating the activities of other organ systems Nervous system Directing long-term changes in the activities of other organ systems Endocrine system Internal transport of cells and dissolved materials, including nutrients, wastes, and gases Cardiovascular system Lymphatic system Defense against infection and disease Delivery of air to sites where gas exchange can occur between the air and circulating blood Respiratory system Processing of food and absorption of organic nutrients, minerals, vitamins, and water Digestive system Elimination of excess water, salts, and waste products; control of pH Urinary system Reproductive system Production of sex cells and hormones

8. Homeostasis Ability to keep the internal environment nearly constant • For the body’s cells to survive and function properly, the composition and temperature of interstitial fluid must remain constant. • Body’s cells are said to be in homeostasis when the internal environment contains: • The optimal concentration of gases • The optimal concentration of nutrients • The optimal concentration of ions and water • At the optimal temperature

9. Homeostasis • All body systems interact to maintain homeostasis through a combination of hormonal and nervous mechanisms. • Alterationsin homeostatic state = diseaseordysfunction → death (Homeostasis is about staying alive). • It is controlled by Negative Feedback Mechanism

10. Importance of homeostasis • The relatively stable internal environment needed to maintain life and provides an optimal environment for cell function. How? • Metabolic reactions are controlled by enzymes • Enzymes work best in a narrow range of temperature & pH only • So, it is important to keep the internal environment as steady as possible

11. Homeostatically regulated Variables • Body Temperature. • Blood Composition (ions, sugars, proteins). • Blood Gases (O2 , CO2). • Acid-Base Balance (pH). • Blood pressure, cardiac output, Heart rate. • Respiratory rate and depth. • Secretions of endocrine glands (hormones).

12. Set point: The ideal normal value of a variable (e.g. body temperature 37oC, pH 7.4) • Variables fluctuate around the set point to establish a normal range of values • Blood pressure (100 - 140 mmHg) • Heart rate (60 - 100 beat/min) • Respiratory rate (12 - 16 cycle/min) • Plasma Ca++(9 - 11 mg/dl)

13. Homeostatic control mechanisms Sensory receptors, Control centre, Effectors • The 3interdependent components of control mechanisms are: • Receptor: detects any changes in the environments and sends input signalsalong afferent pathway to the control center. • Control center: determines the set pointat which the variable is maintained and sends output signalsalong efferent pathway to the effector. • Effector: structures that respond to the stimulus and restore the variableto the optimal physiological range. • E.g. Increase in blood sugar levels or body temperature

14. Homeostatic Control Mechanisms Input:Informationsent alongafferentpathway to 3 Output:Information sentalong efferentpathway to 4 Controlcenter Effector Receptor (sensor) Changedetectedby receptor 2 Response ofeffector feedsback to influencemagnitude of stimulus andreturnsvariable tohomeostasis 5 Stimulus:Produceschangein variable 1 Imbalance Variable (in homeostasis) Imbalance

15. E.g. Regulation of body temperature

16. E.g. Regulation of blood glucose

17. BODY FLUIDS COMPARTMENTS ICF= Intra Cellular Fluid ECF= Extra Cellular Fluid ISF= Interstitial fluid