Introduction to physiology

What is physiology

It is derived from 2 greek words
  • Physis which means nature or origin
  • logos which means study
It is the science of studying the functional activities and their mechanisms in the biological body.

We study physiology to understand the physical and chemical principles that underlie normal functions in order to cure the impairments.

Homeostasis

It is a well-regulated body 

It is the ability of an organism to maintain a stable internal during a fluctuating external environment.

Extracellular fluid or the internal environment of the cell

In the ECF are the ions and the nutrients needed by the cells to maintain life. Thus all cells live in the same environment also known as the ECF. (Internal environment of the body also called milieu Interieur).


The body is sixty percent water and out of that 2/3rd is in the ICF and 1/3rd is in the ECF.

The electrolyte composition of blood plasma, interstitial fluid, and intracellular fluid.

Nutrients like oxygen, glucose, amino acids, and fatty acids are rich in the ECF.


ECF also contains the CO2 which is transported to the lungs that is exported out of the body.

ECF Transport & Mixing System – Blood Circulatory System

 

Movement of blood through the body in blood vessels


Movement of fluid between the blood capillaries and intestinal fluid 


Homeostasis

Discovered in 1929, and coined by Walter Cannon.

All organs and tissues perform functions to maintain homeostasis.

Lungs provide the oxygen to ECF to replenish the oxygen used by cells.

The Nervous system

Organs:
  1. Brain
  2. Spinal cord
  3. Peripheral nerves
  4. Sense organs
Functions:
  1. Directs immediate response to stimuli.
  2. Coordinates and moderates activities of other organ systems.
  3. Provides and interprets sensory information about external conditions.

The skeletal system

Major organs:
  1. Bones
  2. Cartilages
  3. Associated ligaments
  4. Bone marrow
Functions:
  1. Provides support and protection for other tissues
  2. Stores calcium and other minerals
  3. Form blood cells

The endocrine system

Major organs:
  1. Pituitary gland
  2. Pancreas
  3. Thyroid gland
  4. Adrenal glands
  5. Gonads
Functions:
  1. Directs long term changes in the activites of other organ systems.
  2. Adjusts metabolic activity and energy use by the body
  3. Controls many structural and functional changes during development.

The muscular system

Major organs:
Skeletal muscles, associated tendons and ligaments.

Functions:
  1. Provides movement
  2. Provides protection and support for other tissues
  3. Generates heat that maintains body temperature.

The Cardiovascular system

Major organs:
  1. Heart
  2. Blood
  3. Blood vessels
Functions:
  1. Distributes water, blood cells, and dissolved materials including nutrients, waste products, oxygen, carbondioxide
  2. Distributes heat assists in control of body temperature.

The lymphatic system

Major organs:
  1. Spleen
  2. Thymus
  3. Lymphatic nodules
  4. Lymph nodes
  5. Tonsils
Functions:
  1. Defends against infection and disease
  2. Returns tissue fluids to the blood stream.

The urinary system

Major organs:

  1. Kidneys
  2. Urinary bladders
  3. Ureters
  4. Urethra
Functions:

  1. Excretes waste products from the blood
  2. Controls water balance by regulating the amount of urine produced
  3. Stores urine prior to voluntary elimination
  4. Regulates blood ion concentration and PH

The respiratory system

Major organs:
  1. Nasal cavities
  2. sinuses
  3. Larynx
  4. Trachea
  5. Bronchi
  6. Lungs
  7. Alveoli
Functions:
  1. Delivers air to alveoli where it gets exchanged
  2. Provides oxygen to blood stream
  3. Removes carbon dioxide from the blood stream
  4. Produces sound for communication

The digestive system

Major organs:
  1. Teeth
  2. Pharynx
  3. Tongue
  4. Esophagus
  5. Stomach
  6. Small intestine
  7. Large intestine
  8. Gall bladder
  9. Pancreas
Functions:
  1. Processes and digests food
  2. Absorbs and conserves water
  3. Absorb nutrients
  4. Stores energy reserves

The male reproductive system

Major organs:
  1. Testes
  2. Epididymis
  3. Ductus deferens
  4. Seminal vesicles
  5. Prostate gland
  6. Penis
  7. Scrotum
Functions:
Produces male sex cells and hormones.

The female reproductive system

Major organs:
  1. Ovaries
  2. Uterine tubes
  3. Uterus
  4. Vagina
  5. Labia
  6. Clitoris
  7. Mammary glands
Functions:
  1. Produces female sex cells and hormones
  2. Supports developing embryo from conception to delivery
  3. Provides milk to nourish new born infant.

The integumentary system

Major organs:
  1. Skin
  2. Hair
  3. Sweat glands
  4. Nails
Functions:
  1. Protects against environmental hazards
  2. Helps regulate body temperature
  3. Provides sensory information
  4. Storage function
  5. Synthesis of Vitamin D
  6. Excretory function
  7. Absorption
  8. Secretory functions




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