Anatomy and Physiology

Anatomy – A branch of science that deals with the structure of body parts, their forms and organization.

Physiology – A branch of science that is concerned with the functions of body parts. (what they do and how they do it)

Levels of organization- atoms, molecules, organelles, cells, tissues, organs, organ systems, and the human organism

  • Atoms – microscopic particles

    • Molecules – Atoms joined together

    • Macromolecules – molecules joined together to form larger molecules

    • Organelles – Small structures located inside a cell that are made up of macromolecules

    • Cell

      1. Made up of organelles

      2. The basic unit of structure and function

      3. Vary in size, shape, and function

      4. Are microscopic

    • Tissue – Cells that are organized into layers

    • Organ – A group of interacting tissues working together for a common goal

    • Organ System – A group of organs that function closely together

    • Organism – A group of organ systems working together

    • Movement – refers to the self-initiated change in position or internal body parts

    • Responsiveness – sense change inside and outside of the body

    • Growth – increase in body size

    • Reproduction – making of a new individual

    • Respiration – obtaining O2, using O2, and removing CO2

    • Digestion – food substances are broken down and used by body for energy

    • Absorption – passage of digestive products to body fluids

    • Circulation – movement of substances from place to place within the body

    • Assimilation – chemically changing absorbed substances

    • Excretion – removal of wastes

    • METABOLISM – is the sum total of chemical reactions in the body that break down substances and build them up.

    • Requirements of an Organism

      1. Water – required for metabolism, transports substances, regulates body temperature

      2. Food – provide body with chemical energy and materials to build new matter

      3. Oxygen – used to release energy from food.

      4. Heat – it is the product of metabolic reactions (more heat = faster metabolism)

      5. Pressure – air pressure to get O2 to lungs & CO2 out; blood pressure to pump blood through blood vessels

    • Homeostasis – tendency to maintain a stable internal environment with narrow limits (i.e. Thermostat)

      1. Shivering – muscular contractions that produce heat in cold environments

      2. Sweating – blood vessels in skin dilate (open up), blood carrying heat from deeper tissues goes to the surface, and the heat evaporates through the skin as sweat.

    • Body Cavities – spaces where organs are found

      1. Cranial – skull and brain

      2. Vertebral – spinal cord

      3. Thoracic – between neck and diaphragm

      4. Abdominopelvic – between diaphragm and pelvis

      5. Abdominal – between diaphragm and upper pelvis

      6. Pelvic – enclosed by the hip bones

    • Organ Systems (11 different systems)

      1. Body Covering – INTEGUMENT

      2. Support and Movement – SKELETAL, MUSCULAR

      3. Integration and Coordination – NERVOUS, ENDOCRINE

      4. Transport – CARDIOVASCULAR, LYMPHATIC

      5. Absorption and Excretion – DIGESTIVE, RESPIRATORY, URINARY

      6. Reproductive – REPRODUCTIVE

    • Anatomical position- body standing erect, facing forward, upper limbs at the sides, palms facing forward

    • The human body consists of more than 75 trillion cells that vary in size and shape, yet have much in common.

    • The difference in the cellular shape makes the functions differ.

    • A cell consists of three main parts:

      1. Nucleus

      2. Cytoplasm

      3. Cell membrane

    • With the cytoplasm are organelles that perform specific functions of the cell Cell Membrane

      1. It regulates movement of substances in and out of the cell, and helps cells adhere to other cells.

      2. General Characteristics

        • The cell membrane is thin selectively permeable (choosy)

        • Surface is adapted to increase surface area (villi)

    • Cell Membrane and Structure

      1. Consists of a double layer of phospholipids, with fatty acid tails turned inward, “sandwiched” in the middle

        • Heads are polar (like water)

        • Tails are nonpolar (dislikes water)

      2. The double layer is also known as a “Fat Sandwich” or “Fluid Mosiac” model

    • Cytoplasm

      1. Is a clear liquid which suspends the organelles

      2. Endoplasmic Reticulum (ER) – made of thin membranes, and act as a transport system inside the cell

        • With Ribosomes, it is called Rough ER, and makes proteins

        • Without Ribosomes, it is called Smooth ER, and makes good fats

      3. Ribosomes are found with ER and throughout the Cytoplasm. They make protein and contain RNA

    • The Golgi Apparatus- is made of flattened sacs to package and deliver proteins

      1. Vesicles aid the Golgi by acting as a “Delivery service”, carrying chemicals throughout the cell

    • Mitochondria are the powerhouses of the cell and make energy (Very active cells contain many mitochondria)

    • Lysosomes are the “Garbage Disposals” of the cell – gets rid of the wastes

    • Microfilaments and microtubules are thin “sticks” that serve as the skeleton of the cell

    • A centrosome is made up of two hollow cylinders call centrioles that separate chromosomes during cellular division

    • Cilia and Flagella – are extensions from the cell that aid in movement:

      1. Cilia are found lining the respiratory tract

      2. Flagella can be found on sperm cells

Cilia- short hair-like projections and they propel substances on cell surface

Flagellum- long tail-like projection, provides motility to sperm

  • Nucleus- Is a double-layered organelle with pores and is also “selectively permeable”

      • The nucleolus is composed of RNA and protein and is the site of ribosome production

      • Chromatin consists of loosely coiled fibers of DNA

    • The Cell Membrane is Selectively Permeable

    • Mechanisms of movement across the membrane may be:

      • Passive, requiring no energy from the cell (diffusion, facilitated diffusion, osmosis)

      • Active mechanisms, requiring cellular energy (active transport)

    • Passive Mechanisms

      • Diffusion – random movement of molecules from an area of High concentration to and area of Low concentration

      • Facilitated diffusion – uses membrane proteins that carry BIG molecules across the cell membrane (ie. Glucose)

    • Osmosis – the diffusion of water

      • Water moves from an area of greater water concentration to an area of lower water concentration

Put it another way

  • Water moves from a low solute area to a high solute areaHypertonic – Outside cell has higher solute concentration (water leaves the cell-osmosis and shrinks the cell)

    • Hypotonic – Higher solute inside the cell (water enters the cell via osmosis and the cell expands / bursts.)

    • Isotonic – concentrations of solute outside and inside the cell are equalActive transport

      • Cell uses ATP to move molecules from areas of low concentration to areas of high concentration

        • Crossing the cell membrane

      • Examples – sugars, amino acids, Na, K, Ca, and H ions as well as nutrients in the intestines

    • The series of changes a cell undergoes from the time it is formed until it reproduces

    • The cell cycle consists of interphase, mitosis, cytokinesis, and differentiation

    • The cell cycle is highly regulated – most cells do NOT divide continually

    • Interphase

      • A period of growth in which the cell makes new products

      • The DNA of a cell is replicated in preparation for cell division

    • Mitosis

      • One type of cell division, meiosis, four cells (sperm or egg) are produced, each of which contains half of the parents cell’s genetic information

      • Mitosis is a division of the nucleus that results in each daughter cell receiving and exact copy of the parent cells genetic information

    • Prophase – the first stage of mitosis

      • DNA condenses into chromosomes

      • Nuclear membrane disappears

    • Metaphase

      • Chromosomes align in the middle of the cell

    • Anaphase

      • Chromosomes are pulled apart to opposite sides of the cell and form halves called sister chromatids

    • Telephase, the final stage of mitosis

      • Begins when chromosomes have completed their migration

      • Nuclear membrane reappears

      • Chromosomes begin to unwind back into chromatin

    • Cytokinesis – begins when the cytoplasm divides and a ring pinches the two cells apart

    • Cell Differentiation

      • New cells from mitosis develop into different types of cells with specialized functions

Stem cell

  • can divide to form two new stem cells

    • can divide to form a stem cell and a progenitor cell

    • totipotent – can give rise to any cell type

    • pluripotent – can give rise to a restricted number of cell types

Progenitor cell

  • committed cell

    • can divide to become any of a restricted number of cells

    • pluripotent