The Human Body: An Orientation

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The Human Body An Orientation


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The Human Body An Orientation

• Anatomy the study of structure
• Physiology the study of function

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Levels of Structural Organization
Smooth muscle cell
Molecules
Cellular levelCells are made up of molecules
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Atoms
Chemical levelAtoms combine to form molecules
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Smooth muscle tissue
Heart
Tissue levelTissues consist of similar types of
cells
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Cardiovascular system
Blood vessels
Epithelial tissue
Smooth muscle tissue
Blood vessel (organ)
Organismal levelThe human organism is made up of
many organ systems
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Connective tissue
Organ levelOrgans are made up of different types
of tissues
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Organ system levelOrgan systems consist of
different organs that work together closely
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4 Types of Organic Molecules

• 1. Carbohydrates
• Sugars
• Empirical formula CH2O
• Three forms Monosaccharide, Disaccharide,
  Polysaccharide
• Quick Energy in body
• Glucose, Sucrose, Starch, Glycogen

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• 2. Lipids
• Monomers - fatty acids and glycerol
• Hydrophobic
• Make waterproof coverings (part of cell membrane)

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• 3. Proteins
• Monomers - amino acids (20 naturally occurring)
• Bonded by peptide bonds
• Includes enzymes (lock and key model)

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• 4. Nucleic Acids
• Monomers-Nucleotides
• DNA and RNA
• Genetic Expression and protein synthesis

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Life Functions of Humans

• Maintaining boundaries
• Keeping internal and external environments
  separate
• Cells use the cell membrane
• Humans use integumentary system

• Movement
• Moving muscles, bones, blood, urineetc

• Responsiveness
• Also called irritability
• Sensing stimuli and responding to them

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• Digestion
• Breaking down polymers to use as energy
• Hydrolysis

• Metabolism
• All chemical reactions that happen in the body

• Excretion
• Moving wastes out of body
• Includes digestive system and respiratory system

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• Reproduction
• Making a new organism or new cells
  (mitosis/meiosis)

• Growth
• Increase in body size

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Homeostasis

• Maintaining a constant internal environment

• Every cell, tissue and organ in the human body
  contributes toward total body homeostasis

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Ex Blood cells carry wastes from various tissues
toward kidneys which filters blood and then sends
waste materials toward excretory system
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Homeostatic Control Mechanisms

• Control mechanisms are the way that the body
  maintains homeostasis
• Variable The event that is being regulated
• Receptor A sensor that monitors the environment
• Stimuli Changes in environment

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• Control Centers Analyze the stimuli and
  determines the course of action
• Effector Provides the control centers response
  to the stimuli (also called output)

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Feedback Systems

• Negative feedback
• Output turns off or reduces stimulus
• Variables are changed opposite to stimulus

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Ex Body is cold, you begin to shiver to raise
body temperature Ex Your body needs oxygen,
your respiration rate increases to meet this O2
need
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• Positive Feedback
• Response to stimulus enhances so the output is
  raised
• Usually control infrequent events
• Ex Labor contractions and blood clotting

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• Homeostatic Imbalance
• Negative feedback is overwhelmed and harmful
  positive feedback takes over.
• Ex If heart muscles fail to contract and
  negative feedback can not control the muscles,
  positive feedback takes over and heart failure
  can occur

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Language of Anatomy
Body erect, feet slightly apart, palms facing
forward, thumbs point away from body
Anatomical Position
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• Body Region Terms
• Axial - Makes up the main axis of the
  body-head, neck and trunk

• Appendicular - Appendages that are attached to
  the axis

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Directional Terms

• Superior toward the head
• Inferior away from the head

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• Anterior toward the front of the body
• Posterior back of the body

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• Medial toward the midline
• Lateral away from the midline

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• Proximal closer to the origin of the body
• Distal farther from the origin of the body

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• Superficial toward or at the body surface

• deep away from the body surface more internal

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• Human Body Planes
• Sectioned along a flat surface into the following
  divisions
• Sagittal Vertical plane, divided into left and
  right sides

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• Frontal Plane Vertical plane that divides body
  into anterior and posterior sections.
• Transverse or horizontal plane Divides body into
  superior and inferior parts. Also called cross
  section

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• Body Cavities
• 1. Dorsal Body Cavity - Protects nervous system
  organs
• Includes cranial cavity that encases brain

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• Ventral Body Cavity - Largest body cavity, holds
  the internal organs
• Thoracic Cavity - Superior portion of cavity

• Pleural cavity - Encloses each lung

• Pericardial cavity - Encloses heart

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• Abdominopelvic Cavity - Inferior portion of
  cavity separated from thoracic cavity by
  diaphragm
• Abdominal cavity stomach, intestines, spleen,
  liveretc

• Pelvic cavity bladder, reproductive organs,
  rectum

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Four Types of Tissues

• Epithelial tissue Covering tissue
• Connective tissue Support tissue
• Muscle tissue Movement tissue
• Nervous tissue Control tissue

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Epithelium

• Covers body surface or lines body cavities
• Outer layer of skin, open cavities,
  cardiovascular system (veins/arteries), digestive
  system, respiratory system, covers walls of
  organs, forms glands

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Functions of epithelial tissue

1. Protection
2. Absorption
3. Filtration
4. Excretion
5. Secretion
6. Sensory Reception

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• Special characteristics of epithelial tissue
• 1. Supported by connective tissues
• Epithelial tissue rests upon connective tissue
  that forms a basement membrane

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• 2. Avascular
• Epithelial tissue has no blood vessels (only
  capillaries)

• Epithelial tissues does have nerves

• 3. Regeneration
• Epithelial tissue goes through mitosis
  quickly-this tissue is replaced quickly

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• How do we differentiate epithelial tissue?
• 1. Layers
• Simple Thin layer usually used for absorption
• Stratified Thick layer of 2 or more cells used
  for protection (skin)

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• 2. Shape of cells
• All polyhedral shape, allows for close
  connection of cells

• Cell nuclei conform to shape

• 3 shapes
• 1. Squamous cells - flat and scale like

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2. Cuboidal cells - box-like or blunt pyramids
3. Columnar cells - tall and column shaped
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• Simple Squamous Epithelium
• Cells flattened laterally, not much cytoplasm
• Found where filtration and the exchange of
  substances by diffusion is needed
• Kidneys and lungs

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• Simple Cuboidal Epithelium
• Secretion and absorption cells
• Walls of small ducts of glands
• Kidney tubules
• Looks like strings of beads when viewed
  microscopically

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• Simple Columnar Epithelium
• Layers of tall cells with closely packed
  membranes
• Lines digestive tract from the stomach to the
  rectum
• Absorption and secretion cells

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• Modifications of columnar
• Microvilli Projections that increase absorption
• Goblet cells Secrete protective mucus

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• Pseudostratified Columnar Epithelium
• Layers of different height cells that rest on a
  basement membrane (appears layered)
• Secretes or absorbs
• Ciliated version are goblet cells that line the
  respiratory tract

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• Stratified Epithelial Tissue
• Stratified Squamous Tissue
• Most widespread type (areas of wear and tear)
• Skin
• Stratified Cuboidal Tissue
• Rare in body, usually found in glands (mammary
  and sweat)
• Stratified Columnar Tissue
• Pharynx, male urethra

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Connective Tissue

• Found everywhere, most abundant of primary
  tissues

• Skin is mostly connective tissue

• 4 classes of connective tissue
• 1. Connective tissue proper
• 2. Cartilage
• 3. Bone Tissue
• 4. Blood

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• 3 elements make up connective tissue
• 1. Ground Substance
• Material that fills in space between cells, also
  called matrix
• 2. Fibers
• Provide support
• Collagen Fibers Very strong, high tensile
  strength, also called white fibers
• Elastic Fibers Stretchy fibers made
• of elastin, found in lungs, blood vessels, also
  called yellow fibers

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• Reticular Fibers Fine network of collagen found
  around capillaries

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• 3. Cells
• Blast forming (baby or developing cells)
• Cyte cell (adult cells)
• Fibroblast/Fibrocyte Cells in connective tissue
  proper
• Chondroblast/Chondrocyte Cartilage cells
• Osteoblast/Osteocyte Bone cells
• Hematopoietic Stem Cells Blood developing cells

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• Types of Connective Tissue

1. Connective Tissue Proper loose connective
tissues
a. Areolar Connective Tissue

• Supports and joins fibers of other tissues
  universal packing material of tissues

• Holds body fluids

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• Defends against infection- when an area is
  inflamed, this tissue soaks up extra body
  fluids-called edema

• Stores nutrients in fat

• Most widespread connective tissue

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• b. Adipose Tissue

• Fat storage tissue

• Adipocytes (fat cells) 90 of tissue mass, large,
  rounded, with large fat droplets, faint outlines

• High amount of veins, arteries, metabolic
  activity, nutrient storage ability

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• Acts as a shock absorber, insulator and energy
  storage site

• 18 of an average persons body weight is this
  type of tissue

• Can be deposited around organs such as the heart,
  lymph nodes and various muscles

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c. White Fibrous Connective Tissue - Dense
Regular Connective Tissue

• Tendons and ligaments

• Matrix of regular arranged collagenous fibers

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• 2. Cartilage

• Resists tension and compression

• Tough, flexible tissue

• Avascular, no nerve fibers

• Receives nutrients from blood vessels located in
  the connective tissues that surround
  it

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• Ground substance is collagen

• Chondroblasts in growing cartilage until
  maturity-becomes chondrocyte

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• Types of Cartilage
• 1. Hyaline

• gristle

• Most abundant cartilage in body

• Matrix appears bluish-white

• Trachea, lungs, nose, rib attachment to sternum,
  growth plate (epiphyseal plate), embryonic
  skeleton

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2. Elastic

• Elastin fibers

• External ear, epiglottis

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3. Fibrocartilage

• Compressible, resists tension

• Support and pressure

• Intervertebral discs, cartilage of knee

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• 3. Bone Tissue

• Support and protect body

• Provide cavities for fat storage and the
  synthesis of blood cells

• Matrix includes calcium salts

Cells Osteoblasts (develop bones)
Osteocytes (mature bones)
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• 4. Blood Tissue

• Consists of red blood cells, white blood cells,
  lymphocytes, monocytes, eosinophils, basophiles

• Is considered connective tissue, but it doesnt
  connect anything

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Muscle Tissue

• Responsible for body movement

• Three types

skeletal muscle,
cardiac muscle,
smooth muscle
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Nervous Tissue

• Main component of nervous system (brain, spinal
  cord, nerves)

• Cells Neurons

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Tissue Repair

• Process
• 1. Inflammation

• Tissue trauma causes inflammation chemicals to be
  released

• Is a negative feedback system-causes capillaries
  to dilate to accommodate WBCs and clotting
  factors

• Clot forms, the part of the clot that is exposed
  to air becomes a scab

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2. Organization

• Clot is replaced by granulation tissue which
  becomes scar tissue

3. Regeneration and fibrosis

• Regeneration
• New tissue (same type) takes the place of the
  damaged tissue

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• Fibrosis
• Fibrosis connective tissue (scar tissue) takes
  the place of the damaged tissue

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Tissue Development

• Tissues develop from three germ layers
• Ectoderm
• Mesoderm
• Endoderm

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By second month of development, all tissues have
appeared and all organs are formed
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Tissue cells (except neural cells) remain mitotic
until adulthood is reached

• As adults only blood and skin cells are highly
  mitotic

• Skin cells can go through mitosis once a day