M4 overview

• Cellular level

  Considered when a variety of molecules combine to form the fluid and organelles of a body cell
• Cell

  Smallest independently functioning unit of a living organism
• Cell

  • Carries out basic life processes that allow the body to survive
  • Most human cells are specialized in structure and function to carry out other specific roles
  • Human body may consist of as many as 200 different types of cells, each with a special job to do
• Cells

  • Some act as individual cells and are not attached to one another
  • Many act together with other similar cells as part of the same tissue, so they are attached to one another and cannot move freely
  • Some can divide readily and form new cells
  • Some can divide and form new cells only under exceptional circumstances
  • Many have the primary job of producing and secreting a particular substance, such as a hormone or an enzyme
• All the different cell types within an individual human organism are genetically identical
• Differential regulation of genes

  Allows cells with the same genes to be very different because different genes are expressed depending on the cell type
• Tissue Level

  Groups of connected cells form tissues. The cells in a tissue may all be the same type, or

  they may be of multiple types. In either case, the cells in the tissue work together to carry

  out a specific function. There are four main types of human tissues: connective, epithelial,

  muscle, and nervous tissues.
• Epithelial Tissues


  Tissue made up of cells that line inner and outer body surfaces, such as the skin and the inner surface of the digestive tract
• Mucous membrane


  Epithelial tissue that lines inner body surfaces and body openings
• Mucous membrane

  • Produces mucus, a slimy substance that coats mucous membranes and traps pathogens, particles, and debris
• Epithelial tissue

  • Protects the body and its internal organs
  • Secretes substances such as hormones in addition to mucus
  • Absorbs substances such as nutrients
• Epithelial tissue description

  Most epithelial tissue is described with two names, the first describing the number of cell layers and the second describing the shape of the cells
• Muscle Tissues

  Cells that have the unique ability to contract or become shorter
• Major types of muscle tissue

  • Skeletal
  • Smooth
  • Cardiac
• Skeletal muscles


  • Striated or striped in appearance
  • Attached to bones
  • Enable body movement
  • Under voluntary control
• Smooth muscles


  • Nonstriated
  • Found in walls of blood vessels, reproductive, gastrointestinal, and respiratory tracts
  • Not under voluntary control
• Cardiac muscles


  • Striated
  • Found only in the heart
  • Cause the heart to beat
  • Not under voluntary control
• Nervous Tissues. Nervous tissue is made up of neurons and other types of cells

  generally called glial cells. Neurons are composed of cell body and extensions. The cell

  body contains the nucleus, and the extensions make connections with the other tissues

  and neurons. Neurons transmit electrical messages while the glial cells play supporting

  roles. Nervous tissue makes up the central nervous system (mainly the brain and spinal

  cord) and peripheral nervous system (the network of nerves that runs throughout the rest

  of the body).
• Organ


  A collection of tissues joined in a structural unit to serve a common function
• Organs exist in most multicellular organisms, including not only humans and other animals but also plants
• Organelle

  The functional equivalent of an organ in single-celled organisms such as bacteria
• Although organs consist of multiple tissue types, many organs are composed of the main tissue that is associated with the organ's major function and other tissues that play supporting roles
• The main tissue may be unique to that specific organ
• Main tissue of the heart

  • Cardiac muscle
• Heart

  • Performs the function of pumping blood
  • Includes nervous and connective tissues required for its function
  • Nervous tissues control the beating of the heart
  • Connective tissues make up heart valves that keep blood flowing in just one direction
• Vital organs for human survival

  • Heart
  • Brain
  • Kidneys
  • Liver
  • Lungs
• If any of the five vital organs stops functioning, the death of the organism is imminent without medical intervention
• Organ System Level

  Functionally related organs often cooperate to form whole organ systems.
• Organs of the integumentary system include the skin, hair, and

  nails. The skin is the largest organ in the body. It encloses and protects the body and is

  the site of many sensory receptors. The skin is the body’s first defense against

  pathogens, and it also helps regulate body temperature and eliminate wastes in sweat.
• Skeletal System. The skeletal system consists of bones, joints, teeth. The bones of

  the skeletal system are connected by tendons, ligaments, and cartilage. Functions of

  the skeletal system include supporting the body and giving it shape. Along with

  the muscular system, the skeletal system enables the body to move. The bones of

  the skeletal system also protect internal organs, store calcium, and produce red and

  white blood cells.
• Muscular System. The muscular system consists of three different types of muscles,

  including skeletal muscles, which are attached to bones by tendons and allow for

  voluntary movements of the body. Smooth muscle tissues control the involuntary

  movements of internal organs, such as the organs of the digestive system,

  allowing food to move through the system. Smooth muscles in blood vessels

  allow vasoconstriction and vasodilation and thereby help regulate body temperature. Cardiac muscle tissues control the involuntary beating of the heart, allowing
• Nervous System. The nervous system includes the brain and spinal cord, which make

  up the central nervous system, and nerves that run throughout the rest of the body,

  which make up the peripheral nervous system. The nervous system controls both

  voluntary and involuntary responses of the human organism and also detects and

  processes sensory information.
• Endocrine System. The endocrine system is made up of glands that secrete hormones

  into the blood, which carries the hormones throughout the body. Endocrine hormones

  are chemical messengers that control many body functions, including metabolism,

  growth, and sexual development. The master gland of the endocrine system is

  the pituitary gland, which produces hormones that control other endocrine glands. Some

  of the other endocrine glands include the pancreas, thyroid gland, and adrenal glands.
• Cardiovascular system


  Also called the circulatory system
• Components of the cardiovascular system

  • Heart
  • Blood
  • Arteries
  • Veins
  • Capillaries
• Heart

  • Pumps blood
• Blood vessels

  • Blood travels through them
• Transport in the cardiovascular system

  1. Oxygen from lungs transported to cells

  2. Nutrients from digestive system transported to cells

  3. Carbon dioxide and waste picked up from cells and transported to lungs and kidneys for elimination

  4. Equalizes body temperature

  5. Transports endocrine hormones to cells
• The cardiovascular system equalizes body temperature and transports endocrine hormones to cells in the body where they are needed
• Urinary System. The urinary system includes the pair of kidneys, which filter excess

  water and a waste product called urea from the blood and form urine. Two tubes called

  ureters carry the urine from the kidneys to the urinary bladder, which stores

  the urine until it is excreted from the body through another tube named the urethra. The

  kidneys also produce an enzyme called renin and a variety of hormones. These

  substances help regulate blood pressure, the production of red blood cells, and

  the balance of calcium and phosphorus in the body.