INTRO TO ANATOMY & CELL HISTOLOGY

Introduction to Anatomy (CH 1 and Atlas A)

• Anatomy - study of structure 

• Physiology - study of function

• Anatomical variation - variation in a specific structure 

  • Models account for the average person but sometimes people have some structures absent while others have it present 

• Levels of organization

  • Organism 

  • Organ systems

  • Organs 

  • Tissue

  • Cells

  • Organelles

  • Macromolecule

  • Molecule

  • Atom

• Homeostasis - organism maintains internal stability 

  • Dynamic equilibrium - internal state of body best describe in which there is a certain set point value for a given variable (fluctuates around this point)

• Negative feedback - process in which the body senses a change and activates mechanisms that negate or reverse it - key mechanism for maintaining health 

  • Blood pressure - gravity pulls blood down from head, transmits signal to heart, heart pumps blood faster to raise blood pressure and return body back to homeostasis

  • 3 components: receptor (structure senses change), integrating control center (process info), effector (cell/organ carries out final corrective action)

• Positive feedback - amplifying cycle which physiological change leads to even greater change in same direction - normal way of producing rapid change

  • Woman giving birth - head pushes on cervix, signal sent to brain, brain releases oxytocin, oxytocin stimulates uterine contractions

  • Often harmful because of self-amplifying nature

• Body planes

  • Sagittal - vertical through body (R L sides)

  • Frontal - perpendicular to sagittal, divides into front and back 

  • Transverse - top and bottom 

• Directional terms

  • Ventral/anterior - front

  • Dorsal/posterior - back

  • Superior - above 

  • Inferior - below

  • Medial - toward median plane

  • Lateral - away from median plane

  • Proximal - close to point of attachment

  • Distal - far from point of attachment

  • Superficial - surface

  • Deep - deep

Histology/Cell Transport (CH 3, CH 5)

• Structure of plasma membrane

  • Function:

    • Define cell boundaries

    • Governs interactions with other cells

    • Controls passage of material in and out of cells

  • Phospholipid bilayer 

    • Hydrophobic tail 

    • Hydrophilic head

    • Drift laterally keeping membrane fluid

    • Most common

  • Cholesterol 

    • Holds phospholipids still and stiffen membrane

  • Glycolipids 

    • Phospholipids with short carbohydrate chains on extracellular face

  • Membrane proteins

    • Integral proteins - penetrate and pass completely through

    • Peripheral - do not pass all the way through, adhere to face of membrane 

    • Function:

      • Receptor

      • Second messenger system

      • Enzyme channels

      • Carriers

      • Cell ID markers

      • Cell adhesion

  • Glycolax 

    • Fuzzy coat to external plasma membrane

    • Functions:

      • Protection

      • Immunity to infection

      • Cell adhesion

      • Defense against cancer

      • Fertilization 

      • Transplant capability 

      • Embryonic development

  • Microvilli 

    • Extensions of membrane that increase surface area 

    • Absporton 

  • Cillia

    • Hair like antenna detects surrounding 

    • Help with balance in inner ear and light detection in retina 

• Membrane transport

  • Passive - no ATP

    • Filtration - particles driven through membrane by physical pressure 

      • Water and small molecules 

    • Diffusion - net movement of particles from high to low concentration

      • Factors that can affect:

        • Temperature

        • Molecular weight

        • Steepness of gradient

        • Membrane surface area 

        • Membrane permeability 

    • Osmosis - WATER ONLY

      • Hypotonic - cell absorbs more water and swell (higher concentration of solute outside)

      • Hypertonic - cell shrivels and loses water (higher concentration inside than outside)

      • Isotonic - no cell change volume 

  • Active - consume ATP

  • Carrier-mediated mechanisms - use membrane protein to travel across membrane

    • Specificity - only binds to certain solutes 

    • Uniport - one type of solute

    • Symport - two types of solute or more simultaneously 

    • Antiport - two types or more in opposite directions 

    • 3 types: 

      • Facilitated diffusion - moves down its concentration gradient, does not consume ATP

      • Primary active transport - moves up the concentration gradient, needs to consume ATP

      • Secondary active transport - carrier moves solute down gradient but uses ATP indirectly 

  • Vesicular transport - moves large particles 

  • Endocytosis - 

  • Endocytosis—vesicular processes that bring material into cell

    • Phagocytosis—“cell eating,” engulfing large particles

      • Pseudopods; phagosomes; macrophages

    • Pinocytosis—“cell drinking,” taking in droplets of ECF containing molecules useful in the cell

      • Membrane caves in, then pinches off pinocytic vesicle

    • Receptor-mediated endocytosis—particles bind to specific receptors on plasma membrane

      • Clathrin-coated vesicle

  • Exocytosis—discharging material from the cell 

  • Utilizes motor proteins energized by ATP

• Categories of body tissue 

  • Epithelial 

    • Functions: 

      • Protect deeper tissues from injury and infection

      • Produce and release chemical secretions

      • Excrete wastes

      • Absorb nutrients 

      • Selective filtration

      • Sense stimuli 

    • High rate of mitosis 

    • Basement membrane - layer between epithelium and underlying connective tissue 

    • Basal surface - surface of epithelial cell facing basement membrane

    • Apical surface - surface of epithelial cells facing away from basement membrane 

    • Simple squamous - permit rapid diffusion or transport of substances (alveoli, serosa)

    • Simple cuboidal - absorption and secretion (liver, thyroid, mammary and salivary glands)

    • Simple columnar - absorption and secretion (lining of GI tract, uterus)

    • Pseudostratified - secretion (respiratory tract)

    • Stratified squamous - most common in body

      • Keratinized - found on skin surface, abrasion resistant (palms)

      • Nonkeratinized - lacks surface layer of dead cells, resists abrasion and penetration of pathogens (tongue, esophagus)

    • Stratified cuboidal - secrete sweat (sweat gland ducts)

    • Transitional - filling of urinary tract (ureter and bladder)

  • Connective - support, connect, and protect organs

    • Functions

      • Binding of organs

      • Support

      • Physical protection

      • Immune protection

      • Movement

      • Storage

      • Heat production

      • Transport 

    • Cells

      • Macrophages

      • Fibroblasts

      • Leukocytes

      • Plasma cells

      • Mast cells

      • Adipocyte

    • Fiber types

      • Collagenous - tough and flexible, found in tendons and ligaments

      • Reticular - thin collagen fibers found on spleen

      • Elastic - allow stretch and recoil 

    • Areolar - underlies epithelial, contains blood vessels 

    • Reticular - supportive framework for lymphatic organs

    • Dense regular - tendons and ligaments

    • Dense irregular - withstand stress, deeper layer of skin

    • Adipose - stores energy, insulation, cushion

    • Hyaline cartilage - eases joint movement, larynx, fetal skeleton

    • Elastic cartilage - covered with pericardium, external ear

    • Fibrocartilage - resists compression, absorbs shock, pubic symphysis 

    • Compact bone

    • Blood 

  • Nervous 

  • Muscular 

    • Skeletal - voluntary 

    • Cardiac muscle - striated and involuntary 

    • Smooth - involuntary 

  • Tissue repair

    • Healing cut in skin

      • Mast cells and damaged cells release histamine

      • Histamine dilates blood vessels and makes capillaries more permeable 

      • Blood plasma carries antibodies and clotting proteins

      • Blood clot forms

      • Forms scab

      • Macrophages phagocytize and digest tissue debris

      • Macrophages remove blood clot 

      • Fibroblasts deposit new collagen 

      • Cells regenerate 

      • Underlying tissue undergoes fibrosus 

• Steps of inflammation 

  • Vasodilation - greater blood flow to area

  • Vascular permeability - cells become leaky

  • Exudation - fluid, proteins, RBC, WBC

  • Vascular stasis - slowing of blood in bloodstream