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• Digestive System Purpose: converts food into simpler molecules that can be used by the cells of the body; absorbs food and eliminates waste
• Parts of the Digestive System: mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum/colon; accessory organs include the salivary glands, liver, gallbladder, pancreas
• Digestion begins in the mouth:

  • Chemical digestion: salivary glands produce amylase which breaks down sugars and starches
  • Mechanical digestion: teeth grind and break down food into smaller pieces
• Stomach: food is combined with acids and enzymes (chemical digestion); the stomach muscles squeeze and contract (mechanical digestion)
• Small intestine: absorption of food molecules into the blood takes place here; inner surface of small intestine heavily folded and lined with small finger-like projections called villi
• Large intestine: absorbs water and compacts waste
• Rectum/anus: releases wastes outside the body
• Accessory Organs:

  • Pancreas: Produces insulin and glucagon to regulate blood sugar levels; Produces enzymes that break down carbohydrates, proteins, lipids, and nucleic acids
  • Liver: Produces bile, aids in the digestion of fats; Bile is stored in the gallbladder (a pouch under the liver)
• Respiratory System Purpose: Provides O2 to the blood for cellular respiration in the cells and removes CO2 from the body
• Structures of the Respiratory System: Nasal Cavity (Nose), Pharynx (Throat), Epiglottis, Larynx (Voice Box), Trachea (Windpipe), Bronchi, Bronchioles, Alveoli
• Diaphragm: Sheet of muscle below the lungs that separates chest cavity (thorax) from the abdominal cavity; Contracts and relaxes to help inflate and deflate the lungs
• External Respiration: the exchange of O2 and CO2 between the blood in the capillaries of the alveoli and the air occurs in the lungs
• Internal Respiration (Cellular Respiration): cells get energy from the breakdown of glucose in the presence of oxygen; occurs in the mitochondria of the cell
• Circulatory System Purpose: To transport oxygen and nutrients to all the cells in the body and to take carbon dioxide and wastes away from the cells of the body
• Structures of the Circulatory System: heart (main organ that pumps blood), blood vessels (tubes through which blood travels), arteries (carry blood away from heart), veins (carry blood toward heart), capillaries (smallest blood vessels where exchange of nutrients and wastes takes place by diffusion)
• Circulatory System Loops: First loop carries blood between heart and lungs; Second loop carries blood between heart and body
• Skeletal System Functions: Supports & gives shape to body, Protects internal organs, Provides for movement, Stores minerals (calcium), Blood cells produced in bone marrow
• Levels of Organization in the Skeletal System: Compact or Spongy, Femur, Tibia, Vertebrae, Skull, Osteocytes
• Bones are attached to other bones with ligaments; Cartilage is found at ends of bones at joints, reducing friction and not containing blood vessels
• Bone is composed of two types of tissue: Spongy (soft, interior layer of bone tissue, site of red blood cell production, contains bone marrow) and Compact (outer layer of tissue surrounding bone, stores minerals like calcium)
• Interactions: Circulatory System - bones help produce new blood cells and store minerals; Muscular System - bones and muscles work in opposing pairs for body movement; Nervous System - bones protect vital organs of the nervous system like the brain and spinal cord
• Muscular System Function: responsible for movement; Parts: muscles
• Levels of Organization in the Muscular System: Cell, Muscle Fiber, Tissue, Skeletal, Smooth, Cardiac, Organ
• Types of Muscles: Smooth Muscle (found within the walls of organs, helps move food through digestive tract via peristalsis, not under conscious control), Cardiac Muscle (only found in the heart, not under conscious control, striated), Skeletal Muscle (attached to bones, voluntary muscles, striated)
• Muscles are joined to bones by tendons; Most skeletal muscles work in opposing pairs where one muscle contracts, the other relaxes
• Interactions: Digestive System - smooth muscle helps move digested food through the body; Circulatory/Respiratory System - products of cellular respiration from the muscular system are removed via the bloodstream; Nervous System - signals muscles to contract for movement and response to stimuli
• Integumentary System Functions: Protection, Temperature regulation, Sensory organ, Vitamin D production, Excretion of wastes
• Levels of Organization in the Integumentary System: Epidermis, Dermis, Skin, Epithelial Cells
• Parts of the Integumentary System: Skin composed of three layers - Epidermis (outer layer, site of rapid cell division, production of keratin and melanin), Dermis (inner layer, contains major structures of skin), Subcutaneous fat (adipose tissue providing insulation)
• Interactions: Skin is the first line of defense in the immune system response; Circulatory System and skin regulate body temperature; Skin and excretory system excrete water, urea, salts, and other wastes through sweat; Nervous System receptors are located in the skin
• Lymphatic System Function: Collects fluid lost by the blood during movement of nutrients into body tissues and returns it back to the circulatory system; Produces, stores, and circulates white blood cells; Network of vessels and associated organs: lymph vessels
• The lymphatic system functions to collect fluid lost by the blood during the movement of nutrients into body tissues and returns it back to the circulatory system
• The lymphatic system produces, stores, and circulates white blood cells
• Structures of the Lymphatic System:

  • Lymph vessels move the lymph throughout the body
  • Lymph nodes are densely packed areas of tissue that filter the lymph; white blood cells are stored in them
  • Tonsils filter and destroy bacteria
  • Thymus produces hormones that aid in the maturation of T-cells
  • Spleen removes worn-out red blood cells from the circulatory system and contains white blood cells that engulf and destroy bacteria
• The immune system protects the body from disease by producing specialized cells that inactivate or destroy pathogens
• The immune response is triggered by an antigen (virus, bacteria, or other pathogen) where T cells and B cells recognize the specific pathogen and produce antibodies that help destroy the invader and protect the body in the future
• The nervous system maintains homeostasis by controlling and regulating all other parts of the body through sensory functions, interpretation, and response
• Parts of the Nervous System:

  • Neurons are the functional cells that transmit signals through the body
  • There are 3 types of neurons: sensory neurons carry impulses from sense organs to the brain, motor neurons carry impulses from the brain/spinal cord to muscles/organs, and interneurons carry impulses between sensory and motor neurons
• The endocrine system regulates long-term changes in the body such as growth and development by releasing hormones into the bloodstream
• Positive feedback loops intensify or amplify a response to create the desired outcome, like in childbirth