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 functions of 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. Physiology: Start mainly by the questions How and Why, and end by the explanation of the physical and chemical factors that are responsible for the origin, development, and progression of life Example:- How do RBCs carry oxygen and Why do RBCs carry oxygen?
The scope of physiology ranges from studying the activities or functions of individual molecules and cells to the interaction of our bodies with the external world

4. Levels of Organization

5. Levels of Organization of the Human Body
1. The Chemicals 2. The Cell
Atoms
Molecules
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

6. The Tissue Epithelial tissue Connective tissue Muscle 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

7. 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

8. Organ System
Major Functions
Protection from environmental hazards; temperature control
Integumentary system
Support, protection of soft tissues; mineral storage; blood formation
Skeletal system
Muscular system
Locomotion, support, heat production
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
Respiratory system
Delivery of air to sites where gas exchange can occur between the air and circulating blood
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

9. Ability to keep the internal environment nearly constant
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

10. Homeostasis
All body systems interact to maintain homeostasis through a combination of hormonal and nervous mechanisms.
Alterations in homeostatic state = disease or dysfunction → death (Homeostasis is about staying alive).
It is controlled by Negative Feedback Mechanism

11. 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

12. 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).

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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 ( mmHg)
Heart rate ( beat/min)
Respiratory rate ( cycle/min)
Plasma Ca ( mg/dl)

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

15. Homeostatic Control Mechanisms3
Input: Information sent along afferent pathway to 4
Output: Information sent along efferent pathway to
Control center
Effector
Receptor (sensor) 2
Change detected by receptor 5
Response of effector feeds back to influence magnitude of stimulus and returns variable to homeostasis
Stimulus: Produces change in variable 1
Imbalance
Variable (in homeostasis)
Imbalance

16. E.g. Regulation of body temperature

17. E.g. Regulation of blood glucose
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E.g. Regulation of blood glucose

18. BODY FLUIDS COMPARTMENTS
Total body weight
TBW = 60%
ICF = 40%
ECF = 20%
Plasma = 5 %
¼ ECF
ISF = 15 %
¾ ECF
Transcellular F
BODY FLUIDS COMPARTMENTS
ICF= Intra Cellular Fluid
ECF= Extra Cellular Fluid
ISF= Interstitial fluid