INTRODUCTION TO PHYSIOLOGY

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 BodyCells 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 FunctionObtaining food and O2from the surrounding.

Perform chemical reaction to use food and O2

Food + Oxygen = CO2+ H2O+EnergyEliminate 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 enzymesMuscle Cells - Muscle contractionNerve 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 TISSUEThere are FOUR types of Tissue 1- Muscle Tissue 2- Nervous Tissue 3- Epithelial Tissue 4- Connective Tissue

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1. Muscle TissueMuscle Tissue - for contractionTHREE types of Muscles : 1– Skeletal Muscle 2– Cardiac Muscle 3– Smooth Muscle

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2. NERVOUS TISSUENervous Tissue – Specialized cells for initiation and

transmission of Electrical impulses Brain Spinal cord Nerves

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3. Epithelial TissueTwo types

1. Epithelial lining e.g. Skin, Digestive system

2. Secretary glands e.g. Salivary glands

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Glands – Two typesExocrine - Having duct e.g. salivary glandEndocrine - Ductless e.g. Thyroid gland

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4. Connective TissueConnective 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 SYSTEMSOrgans 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 HOMEOSTASISBody 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 = SameStasis = StayCells 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 SystemsELEVEN 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 LectureWhat 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