HUMAN BODY SYSTEM

• Levels of Organization


  From the simplest to the most complex
• Cells


  • The basic unit of life
• Tissues


  • Clusters of cells performing a similar function
• Organs


  • Made of tissues that perform one specific function
• Organ Systems


  • Groups of organs that perform a specific purpose in the human body
• The purpose of the 11 organ systems is for the human body to maintain homeostasis
• Cell types


  • Muscle tissue
  • Epithelial tissue
  • Connective tissue
  • Nervous tissue
• Muscle tissue


  Most abundant tissue, controls internal movement, digestion, blood through veins, external movement of body
• Epithelial tissue


  Covering for body & organs, linings of organs & vessels
• Connective tissue


  Holds organs in place, ligaments, tendons, some keep organs in place
• Nervous tissue


  Receives messages from body's internal and external messages, analyze data & direct response

  
• The 11 Human Body Systems

  • Nervous system
  • Integumentary system
  • Respiratory system
  • Digestive system
  • Excretory system
  • Skeletal system
  • Muscular system
  • Circulatory system
  • Endocrine system
  • Reproductive system
  • Lymphatic (immune) system
• Circulatory System


  To deliver oxygenated blood to the various cells and organ systems in your body so they can undergo cellular respiration
• Heart


  • The major muscle of the circulatory system, pumps deoxygenated blood into the lungs, where it gets oxygenated, returned to the heart, and then pumped out through the aorta to the rest of the body, valves regulate the flow of blood between the chambers
• With lungs


  Exchange O2 & CO2
• With digestive system


  Pick up nutrients for transport throughout the body
• With excretory


  Blood is filtered to remove toxins and some water
• With nervous system


  Heart-beat regulation & blood pressure
• Nervous System


  To coordinate the body's response to changes in its internal and external environment
• Brain


  • Control center of the body, where all processes are relayed through, consists of cerebrum (controls thought and senses) and cerebellum (controls motor functions)

  
• Spinal Cord


  • Sends instructions from the brain to the rest of the body and vice versa, any organism with a major nerve cord is classified as a chordate

  
• Nerves

  • Conduct impulses to muscle cells throughout the body, neurons clustered into bundles of fibers (axons), 3 types: sensory, motor, interneuron, synapse - point at which a neuron can transfer an impulse to another cell

  
• Central Nervous System (CNS)


  • The control center, Brain - 100 billion cells neurons, Cerebrum - largest part, responsible for learning, intelligence, and judgment, Cerebellum - coordinates and balances actions of muscles, Brainstem - regulates blood pressure, heart rate, breathing, and swallowing

  
• Nervous system


  Interactive with all other systems in the body
• Respiratory System


  To provide the body with a fresh supply of oxygen for cellular respiration and remove the waste product carbon dioxide
• Nose


  • Internal entry and exit point for air
• Pharynx


  • Serves as a passage way for both air and food at the back of the throat
• Larynx


  • Your "voicebox", as air passes over your vocal chords, you speak
• Trachea


  • The "windpipe", or what connects your pharynx to your lungs, a piece of skin, called the epiglottis, covers the trachea when you swallow, preventing food from entering
• Bronchi


  • The two large passageways that lead from the trachea to your lungs (one for each lung), further subdivided into bronchioles, eventually leading to tiny air sacs called alveoli
• Lungs


  • Contain the alveoli, bronchi and connective tissue, the diaphragm is the muscle that causes you to breathe, hiccups are involuntary contractions of the diaphragm
• Alveoli are the air sacs of the lungs, they have thin walls made of simple cells and are surrounded by blood capillaries, gas exchange occurs in the alveoli, the surface of alveoli are covered in a thin lipoprotein layer and it prevents them from collapsing during exhalation
• Respiratory system


  Directly interacts with the circulatory system, indirectly interacts with the immune system, interacts with the nervous system (smell & taste) - regulation of breathing
• Digestive System


  To convert food particles into simpler micromolecules that can be absorbed into the bloodstream and used by the body
• Mouth


  • To chew and grind up food, saliva also begins the chemical breakdown
• Esophagus


  • Pipe connecting mouth to stomach
• Stomach


  • Secretes an extraordinarily strong acid (pH = 2) that leads to breakdown of food, once the food is broken down in the stomach and mixed with digestive juices, it is called chyme
• Pancreas


  • Secretes digestive enzymes, produces the hormone insulin that regulates blood sugar levels, also help neutralize stomach acid
• Liver


  • Produces bile, which breaks down fats in foods
• Gallbladder


  • Pouch-like organ that stores bile for future use