Physiology Behrouz Mahmoudi Introduction 1

Things ” organized to use energy and raw materials from their environment, maintain their integrity and reproduce. Life Physiology Physiology is the study of the normal function of cell, tissue, organs, systems and organisms 2

Physiological processes arise through evolution ▸ Natural selection -process by which traits that enhance a species survival are able to produce more surviving members than others not having those characteristics 3

Integumentary system Nervous system Skeletal system Endocrine system Muscular system Cardiovascular system Lymphatic system Urinary system Respiratory system Digestive system Reproductive system 4

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Homeostasis Homeostasis is a stable internal environment Every organism must maintain homeostasis for survival Homeostatic regulation is responsible for keeping internal environment within certain limits. Two general points within homeostasis Autoregulation or intrinsic regulation – results when cell, organ or system adjusts its activity automatically. Extrinsic regulation - results from activity of nervous system or endocrine system 17

A homeostatic regulatory mechanism consist of : – A receptor – senses an environmental change or stimuli. – A control center –processes information supplied by receptor and generates a response (command) – An effector – an organ or cell that responds to the command of control center. A variation outside the desired range triggers an automatic response to correct the situation – Negative feedback Homeostatic regulation involves 18

Negative Feedback: The Control of Body Temperature 19

Positive Feedback: Blood Clotting In positive feedback an initial stimulus produces a response that enhances the change in the original condition. For instance: Damage to blood vessel wall will cause release of chemicals. Chemicals will trigger blood clotting Clotting process increases release of chemicals More chemicals means accelerated clotting Accelerated clotting means more chemicals 20

Body cavities are internal chambers holding vital organs – Cavities protect vital organs – Cavities allow organs to change in shape and size Two body cavities – Dorsal body cavity includes the cranial cavity and the spinal cavity – Ventral body cavity includes the thoracic cavity and the abdominopelvic cavity Body Cavities 21

Body Cavities 22

X-rays Computerized tomography (CT) scans Magnetic resonance imaging (MRI) scans Ultrasound images Digital subtraction angiography (DSA) Clinical technology allows many different views of the body 23

X-rays 24

Special Scanning Methods CT-SCAN: computerized tomography scan 25

Magnetic resonance imaging (MRI) scans 26

Ultrasound images 27

angiography 28