Human Skeletal System

Skeletal System

• Functions:
  • Supports the body
  • Protects internal organs
  • Provides movement through joint articulation
  • Produces blood cells
  • Stores minerals (e.g. calcium, phosphorus)
• Components:
  • Bones (206 in adult human skeleton)
  • Joints (connect bones)
  • Ligaments (connect bones to each other)
  • Tendons (connect muscles to bones)
• Types of bones:
  • Long bones (e.g. femur, humerus)
  • Short bones (e.g. carpals, tarsals)
  • Flat bones (e.g. ribs, sternum)
  • Irregular bones (e.g. vertebrae, pelvis)

Nervous System

• Functions:
  • Controls and coordinates body functions
  • Interprets and responds to sensory information
  • Regulates body temperature, hunger, and thirst
• Components:
  • Central nervous system (CNS): brain and spinal cord
  • Peripheral nervous system (PNS): nerves
  • Somatic nervous system: controls voluntary movements
  • Autonomic nervous system: controls involuntary movements
• Types of neurons:
  • Sensory neurons: transmit sensory information
  • Motor neurons: transmit motor signals
  • Interneurons: integrate and process information

Respiratory System

• Functions:
  • Brings oxygen into the body
  • Removes carbon dioxide from the body
• Components:
  • Upper respiratory tract: nose, mouth, pharynx, larynx
  • Lower respiratory tract: trachea, bronchi, lungs
  • Diaphragm: muscle that separates chest and abdominal cavities
• Process of breathing:
  • Inhalation: diaphragm contracts, air enters lungs
  • Exhalation: diaphragm relaxes, air leaves lungs

Muscular System

• Functions:
  • Moves body parts
  • Maintains posture
  • Regulates body temperature
  • Supports movement of other systems (e.g. circulatory, respiratory)
• Types of muscles:
  • Skeletal muscles: voluntary movement
  • Smooth muscles: involuntary movement (e.g. digestive tract)
  • Cardiac muscles: involuntary movement (e.g. heart)
• Muscle structure:
  • Muscle fibers: contractile units
  • Muscle cells: contain multiple fibers

Circulatory System

• Functions:
  • Transports oxygen and nutrients to cells
  • Removes waste products from cells
  • Regulates body temperature
• Components:
  • Heart: pumps blood
  • Arteries: carry oxygenated blood away from heart
  • Veins: carry deoxygenated blood back to heart
  • Blood vessels: capillaries, arterioles, venules
• Blood components:
  • Plasma: liquid portion
  • Red blood cells: carry oxygen
  • White blood cells: immune function
  • Platelets: clotting function

Skeletal System

• Provides support, protection, and movement for the body
• Produces blood cells and stores minerals like calcium and phosphorus
• Consists of 206 bones, joints, ligaments, and tendons in an adult human skeleton
• Bones are categorized into long bones (e.g. femur, humerus), short bones (e.g. carpals, tarsals), flat bones (e.g. ribs, sternum), and irregular bones (e.g. vertebrae, pelvis)

Nervous System

• Controls and coordinates body functions, interprets sensory information, and regulates body temperature, hunger, and thirst
• Comprises the central nervous system (brain and spinal cord), peripheral nervous system (nerves), somatic nervous system (voluntary movements), and autonomic nervous system (involuntary movements)
• Neurons are categorized into sensory neurons (transmit sensory information), motor neurons (transmit motor signals), and interneurons (integrate and process information)

Respiratory System

• Brings oxygen into the body and removes carbon dioxide
• Consists of the upper respiratory tract (nose, mouth, pharynx, larynx), lower respiratory tract (trachea, bronchi, lungs), and diaphragm (separates chest and abdominal cavities)
• The process of breathing involves inhalation (diaphragm contracts, air enters lungs) and exhalation (diaphragm relaxes, air leaves lungs)

Muscular System

• Enables movement, maintains posture, regulates body temperature, and supports movement of other systems
• Comprises skeletal muscles (voluntary movement), smooth muscles (involuntary movement, e.g. digestive tract), and cardiac muscles (involuntary movement, e.g. heart)
• Muscles are composed of muscle fibers (contractile units) and muscle cells (contain multiple fibers)

Circulatory System

• Transports oxygen and nutrients to cells, removes waste products, and regulates body temperature
• Consists of the heart (pumps blood), arteries (carry oxygenated blood away from heart), veins (carry deoxygenated blood back to heart), and blood vessels (capillaries, arterioles, venules)
• Blood components include plasma (liquid portion), red blood cells (carry oxygen), white blood cells (immune function), and platelets (clotting function)