Human Systems:
Body
Organization
Human Body
• 100 trillion cells
• More than 100 kinds of cells
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Organization – cells, tissues, organs, organ systems
Coordination
Control mechanisms
Maintaining internal environment (homeostasis)
Homeostasis and cell function
Cells, tissues, organs
• Cells must do many things to maintain homeostasis
• Cells – different types of function and specialization
Cells, tissues, organs
• Cells form tissues (group of same type of cells performing
same function)
Cells, tissues, organs
• Tissues form organs
• Different functions in same place - coordination
Organ systems
• Organs form organ systems
• Stomach helps in food digestion but cannot digest food alone
• Additional help needed by other organs of the digestive
system
• Mouth (saliva secretion), pancreas, gall bladder, intestine
• Nervous system – brain, spinal cord, nerves
• Organs perform specialized function in a coordinated manner
Cells, tissues, organs
Organ systems
• Organ systems work together to perform body processes
• E.g. cardiovascular system (circulatory system) works with
respiratory system to perform exchange of gases
• Nervous system works with skeletal and muscular systems for
producing movements
• Urinary, digestive and respiratory systems work together for
excretion of wastes
• Digestive and circulatory systems work together to obtain and
distribute nutrients
Organ systems
• Interdependence of organ systems
• Some organs perform jobs essential for more than
one system
• E.g. pancreas – digestive and endocrine systems
• Stomach – digestive system and communication
• Liver – carbohydrate, protein, lipid metabolism, drug
metabolism, detoxification, waste (urea)
management, store materials
Organ systems
• When systems fail
– Systems must function properly and work
together in order to maintain homeostasis
– Failure of even a part of a system can result in a
disorder affecting the whole organism
– may result in death
Organ systems
• E.g. angina – a heart disorder
– Blood supply to heart is restricted
– Heart cannot pump blood efficiently
– Depletion of nutrients and oxygen in body cells
• E.g. diabetes – a pancreatic disorder
– Problem in insulin production or action
– Increase in blood glucose level
– Can damage eyes, kidneys, brain, nerves, movement of
substances, limbs, digestive system