exam for bio

• Skin has three layers: epidermis (outermost), dermis (middle layer), hypodermis/subcutaneous tissue (deepest).
• Functions of the Skin

  maintain water balance

  protects against injury

  excretes various substances

  provides thermoregulation

  receives stimuli

  •temperature

  •pain

  •pressure

  provides basis of recognition pf well-being

  provides place for fat metabolism in the hypodermis
• system of levers that aid muscle action: muscles
• Parts of Muscles

  •Smooth Muscles

  •Skeletal Muscles

  •Cardiac Muscles
• bones: provide support and protection
• Parts of Bones

  long bones

  short bones

  flat bones

  irregular bones
• Joints: the junction between two or more bones
• Cartilage: forms cushion
• ligaments: connect bone to bone
• tendons: attach muscles to bone
• Functions of Muscle

  • Produces contractibility (movement)
  • Running, walking, jumping
  • Produces posture
  • Stabilizes joints
  • Produces heat
• Functions of Cartilage

  • Provides flexible support (ears, nose, and respiratory)
  • Slides across each other (joints)
  • Provides a cushion (joints)
  • No nerves, so no pain during compression of cartilage
• Functions of Bone

  • Provides skeletal support
  • Provides protective enclosure (Skull to protect brain, Long bone to protect blood producing cells)
  • Regulates calcium
  • Provides place for hemopoiesis (Blood cell formation in the body)
• Parts of the Cardiovascular System

  • Heart
  • Arteries
  • Veins
  • Capillaries
• Parts and Functions of the Cardiovascular System

  1. Heart produces blood pressure during systole

  2. Elastic arteries conduct blood and maintain pressure during diastole

  3. Muscular arteries distribute blood and maintain pressure

  4. Arterioles provide peripheral resistance and distribute blood

  5. Capillaries exchange nutrients and waste

  6. Venules collect blood and edema from capillaries

  7. Veins transmit blood to large veins (reservoir)

  8. Large veins receive lymph and return blood to heart (reservoir)
• Lymphatic System


  Returns fluid from the tissues to the circulatory system
• Components of the Lymphatic System

  • Lymph
  • Lymphatic vessels
  • Lymphatic structures
• Lymph nodes


  • Filters and traps foreign particles
  • Contain white blood cells
• Tonsils


  • Protects against bacteria
• Thymus


  • Helps with immunologic cells
• Spleen


  • Clears out old red blood cells
• Functions of the Lymphatic System

  • Removes excess fluids from body tissues
  • Absorbs fatty acids
  • Transports fat
  • Produces immune cells (lymphocytes)
  • Helps combat infections
• Components of the integumentary system

  • Skin
  • Hair
  • Nails
  • Glands
• Functions of the integumentary system

  • Protection
  • Regulation
  • Sensation
  • Secretion
• Epidermis


  The outermost layer of the skin, primarily composed of epithelial cells
• Functions of the epidermis

  • Provides a waterproof barrier
  • Protects against pathogens
  • Regulates body temperature
• Dermis


  A thicker layer beneath the epidermis, consisting of connective tissue, blood vessels, nerve endings, and glands
• Functions of the dermis

  • Provides structural support
  • Regulates temperature
  • Contains nerve endings for sensation
• Hypodermis (Subcutaneous Layer)


  The deepest layer of the skin, composed of fat and connective tissue
• Functions of the hypodermis

  • Insulates the body
  • Stores energy
  • Anchors the skin to underlying tissues
• Hair


  Filamentous strands of dead keratinized cells that grow from follicles in the dermis
• Functions of hair

  • Provides insulation
  • Protects against UV radiation
  • Sensory functions
• Nails


  Hard, keratinized plates covering the dorsal surface of the fingers and toes
• Functions of nails

  • Protects the fingertips and toes
  • Enhances fine touch sensitivity
  • Aids in grasping
• Sebaceous Glands


  Small glands located in the dermis that produce sebum, an oily substance
• Functions of sebaceous glands

  • Lubricates the skin and hair
  • Prevents dehydration
  • Inhibits bacterial growth
• Sweat (Sudoriferous) Glands


  Glands distributed throughout the dermis that produce sweat
• Functions of sweat glands

  • Regulates body temperature through evaporative cooling
  • Excretes waste products
  • Maintains electrolyte balance
• Blood Vessels


  Networks of arteries, veins, and capillaries that supply nutrients and oxygen to the skin
• Functions of blood vessels

  • Regulates body temperature through vasodilation and vasoconstriction