LECTURE--------1
DR ZAHOOR ALI SHAIKH
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What is Physiology ?
 Physiology deals with functions of the body.
 Central aim is to keep the HOMEOSTASIS that is to
keep the INTERNAL- ENVIORNMENT of the cell
constant, so that cells can work.
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Levels of organization in the Body
 Cells are basic units of life.
 Cell is the smallest unit which is capable of carrying
out the processes associated with life.
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Basic Cell Function
 Obtaining food and O2from the surrounding.
 Perform chemical reaction to use food and O2
Food + Oxygen = CO2+ H2O+Energy
 Eliminate CO2 and other waste products.
 Synthesize protein.
 Exchange of material through cell membrane.
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Specialized Function of cells
 Digestive System - secrete digestive enzymes
 Muscle Cells - Muscle contraction
 Nerve Cell - send electrical impulses
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 Cells are organized in Tissues, Organs, Systems and
finally Body.
 Cells of similar structure and function are organized in
Tissues .
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TYPES OF TISSUE
 There are FOUR types of Tissue
1- Muscle Tissue
2- Nervous Tissue
3- Epithelial Tissue
4- Connective Tissue
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1. Muscle Tissue
 Muscle Tissue - for contraction
 THREE types of Muscles :
1– Skeletal Muscle
2– Cardiac Muscle
3– Smooth Muscle
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2. NERVOUS TISSUE
 Nervous Tissue – Specialized cells for initiation and
transmission of Electrical impulses
 Brain
 Spinal cord
 Nerves
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3. Epithelial Tissue
 Two types
1. Epithelial lining e.g. Skin, Digestive system
2. Secretary glands e.g. Salivary glands
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Glands – Two types
 Exocrine - Having duct e.g. salivary gland
 Endocrine - Ductless e.g. Thyroid gland
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4. Connective Tissue
 Connective tissue connects, supports the body
 e.g. Tendon - attach skeletal muscle to bone
Elastin - helps in stretching and recoil of the lungs
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ORGANS
 Organs are composed of tissues (Two or more types )
to perform a particular function.
 E.g. stomach has all four primary tissues i.e. Epithelial,
Muscle, Nervous and connective tissue.
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BODY SYSTEMS
 Organs make the body system.
 Each system works to perform related functions and is
essential for survival of body.
 E.g. – Digestive system works for digestion and
absorption.
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TOTAL BODY
 Composed of organ systems linked together
structurally and functionally.
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CONCEPT OF HOMEOSTASIS
 Body cells work in INTERNAL ENVIRONMENT that
surrounds the body.
 What is Internal Environment ?
 It is aqueous(watery) Extracellular Fluid with which
body cells are in direct contact it is outside the cell but
not inside the cell.
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Extracellular Fluid (ECF)
 What is Extracellular Fluid (ECF) ?
 ECF consists of
-Plasma (fluid portion of blood) and Interstitial fluid
(which surrounds the cells)
 Materials are exchanged between the plasma and
interstitial fluid across the capillary membrane e.g. O2
and nutrition go from plasma to interstitial fluid than
to cell
 Same way waste products go from cell to Interstitial
fluid to plasma.
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HOMEOSTASIS (continued)
 Homeo = Same
 Stasis = Stay
 Cells can only work when Internal environment (cell
surrounding) physical and chemical state is within
narrow physiological limits.
 Homeostasis is essential for survival of each cell.
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HOMEOSTASIS (continued)
 All body system work for Homeostasis so that body
can function.
 How body keeps Internal environment constant.
 E.g.- If CO2 increases – it affects
respiration(increased) to get rid of increased CO2
-when cold outside, our body temperature decreases –
shivering occurs to increase the body temperature.
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HOMEOSTASIS (continued)
 For Homeostasis, Following factors are to be
maintained constant:
-supply of nutrient
-concentration of O2 and CO2
-waste product concentration
-pH as acidity affects enzyme activity
-concentration of water and electrolytes
- Temperature, narrow limit 35-38c
- plasma volume and Blood pressure
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Body Systems
 ELEVEN Body Systems work for Homeostasis :
1. Circulatory system
2. Digestive system
3. Respiratory system
4. Urinary system
5. Skeletal system
6. Muscular system
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Body Systems (CONT)
7. Integumentary system- skin, hair, nails, sweat glands,
temperature regulation
8. Immune system
9. Nervous system
10. Endocrine system
11. Reproductive system
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What you should know from this
Lecture
 What is Physiology ?
 What is Homeostasis?
 What is Internal Environment of the cell?
 What are the functions of cell?
- General
- Specialized
• Organization of the body
Cell – Tissue – Organs – System - Body
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THANK YOU
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