Physiology and Anatomy

Directional Terms

  • Allow description of body parts in relation to each other.
  • Terms assume anatomical position.
  • Key terms:
    • Superior: above.
    • Inferior: below.
    • Anterior: towards the front.
    • Posterior: towards the back.
    • Medial: towards the middle.
    • Lateral: away from the midline.
    • Proximal: toward the point of attachment to the trunk.
    • Distal: away from the point of attachment to the trunk.
    • Superficial: toward the surface of the body.
    • Deep: toward the interior of the body.

Movement Terms

  • Describe movements at joints with precise meanings.
  • Movements applying to many joints:
    • Flexion / extension / hyperextension.
    • Abduction / adduction.
    • Circumduction.
    • Lateral and medial rotation.
  • Movements applying to few joints:
    • Plantarflexion / dorsiflexion (ankle).
    • Eversion / inversion (foot).
    • Protraction / retraction (shoulder, jaw).
    • Depression / elevation (shoulder, jaw).
    • Opposition / reposition (thumb).
    • Supination / pronation (forearm).

Levels of Structural Complexity

  • Chemical level.
  • Cellular level.
  • Tissue level.
  • Organ level.
  • System level.
  • Organism.

Basic Cell Functions

  • Maintaining boundaries.
  • Movement.
  • Responsiveness.
  • Digestion.
  • Metabolism.
  • Excretion.
  • Reproduction.
  • Growth.

Tissue Types

  • Epithelial tissue.
  • Connective tissue.
  • Muscle tissue.
  • Nervous tissue.

Medical Imaging Techniques

  • Sonography.
  • Radiography.
  • Computed Tomography (CT).
  • Magnetic Resonance Imaging (MRI).
  • Positron Emission Tomography (PET).

Body Cavities

  • Dorsal (posterior) cavity:
    • Protects nervous system organs.
    • Subdivisions:
      • Cranial cavity (encases the brain).
      • Vertebral (spinal) cavity (surrounds spinal cord).
  • Ventral (anterior) cavity:
    • Houses internal organs (viscera).
    • Subdivisions:
      • Thoracic cavity.
      • Abdominopelvic cavity.

Thoracic Cavity

  • Contains:
    • Pleural cavities (enclose lungs).
    • Mediastinum (encloses heart, esophagus, trachea).
      • Pericardial cavity (encloses heart).
  • Separated from inferior cavity by the diaphragm.

Abdominopelvic Cavity

  • Contains:
    • Abdominal cavity (stomach, intestines, spleen, liver).
    • Pelvic cavity (urinary bladder, reproductive organs, rectum).
  • Divisions:
    • Four quadrants: right upper, right lower, left upper, left lower.
    • Nine regions: right hypochondriac, epigastric, left hypochondriac, right lumbar, umbilical, left lumbar, right iliac, hypogastric, left iliac.

Serous Membranes

  • Two-layered membranes with fluid in between.
    • Parietal membrane: lines cavity wall (outer layer).
    • Visceral membrane: covers organ in cavity (inner layer).
  • Serous fluid: lubricating fluid between layers.
  • Function: wall off infection, protect from trauma, decrease friction.

Other Body Cavities

  • Oral & digestive cavity: mouth to anus.
  • Nasal cavity: within and posterior to the external nose.
  • Orbital cavities: house the eyes.
  • Middle ear cavities: in temporal bone, transmit sound vibration.
  • Synovial cavities: joint cavities.

Interdependence and Homeostasis

  • Body cells are interdependent; systems integrate to maintain life functions.
  • Homeostasis: maintenance of stable conditions in extracellular fluid (ECF).
  • ECF includes interstitial fluid and plasma.
  • Factors kept within narrow ranges: Gases, nutrients, water volume, pressure, salt concentration, pH, temperature, waste products.

Homeostatic Control Mechanisms

  • Receptor: sensor that monitors the environment and responds to changes.
  • Control center: determines the normal range of condition analyses input from receptor determines appropriate response.
  • Effector: brings about the response- the results of the response then feedback to the control centre via the receptor/afferent pathway and restores balance.

Feedback Mechanisms

  • Negative feedback: response shuts off or reduces the original stimulus. Ex: Temperature.
  • Positive feedback: response enhances the original stimulus. Ex: Uterine contractions.

Organ Systems Working Together

  • Respiratory system: oxygen.
  • Digestive system: glucose.
  • Cardiovascular system: nutrient transport.
  • Urinary system: waste removal (urea, uric acid).
  • Respiratory system: carbon dioxide removal.

Nervous System

  • Central nervous system (CNS): brain & spinal cord (control center).
  • Peripheral nervous system (PNS):
    • Afferent nerves: carry messages to the CNS.
    • Efferent nerves: carry messages from the CNS.
  • Nerves send rapid, short-lived electrical signals.

Endocrine System

  • Controls metabolic activities via hormones.
  • Hormones:
    • Chemicals (proteins or steroids).
    • Produced by endocrine glands.
    • Transported by blood.
    • Act slowly and are long-lived.
  • Controls growth, metabolism, reproduction, digestion, blood pressure, composition of blood plasma.

Nerves vs. Hormones

  • Similarities: cellular communication and stimulus-response mechanisms.
  • Differences: nature of message, speed and duration of responses, target of responses.

Blood Composition

  • Plasma:
    • 90% water.
    • Proteins (e.g., albumin).
  • Formed elements:
    • Erythrocytes (red blood cells).
    • Leukocytes (white blood cells).
    • Platelets.

Red Blood Cells (Erythrocytes)

  • Biconcave disc shape, filled with hemoglobin (Hb).
  • Pick up oxygen in the lungs to drop it off at the tissues throughout the body.
  • Lifespan: 100-120 days, engulfed by white blood cells in the spleen

White Blood Cells (Leukocytes)

  • Defense against infection; raised numbers indicate infection (Leukocytosis).
  • Types:
    • Neutrophils & monocytes: phagocytose damaged cells and invaders.
    • Eosinophils: attack antibody-coated parasites, reduce inflammation.
    • Basophils: contain histamine (dilates vessels) and heparin (prevents clotting).
    • Lymphocytes: crucial to immunity.

Platelets and Blood Clotting

  • Essential for blood clotting (Hemostasis).
  • Three rapid stages:
    • Vascular spasm.
    • Platelet plug formation.
    • Coagulation (blood clotting).

Cell Structure

  • All cells share common features but vary in structure, function, and lifespan.
  • Three main components: plasma membrane, nucleus, cytoplasm.
    • Intracellular: inside the cell.
    • Extracellular: outside of the cell.
    • Cytosol: the liquid within the cell.

Plasma Membrane

  • Separates intra- and extracellular fluids.
  • Controls what comes in and out of the cell.
  • Contains cytoplasm and organelles.
  • Communicates with other cells.
  • Main component: phospholipids (hydrophilic heads, hydrophobic tails) form a bilayer.
  • Fluid-mosaic model: molecules move within the bilayer; mosaic refers to proteins and lipids embedded within.

Plasma Membrane Permeability

  • Semi-permeable: lipophilic and small molecules can move freely (e.g., CO<em>2CO<em>2 and O</em>2O</em>2).
  • Proteins act as channels, carriers, or receptors.

Cytoplasm

  • Material forming all cells, between plasma membrane and nucleus.
  • Consists of:
    • Cytosol: thick, sticky fluid.
    • Inclusions: stored nutrients, pigment.
    • Organelles: carry out specific functions.

Nucleus

  • Cell's control center; regulates metabolic activities, growth, and reproduction.
  • Contains DNA (chemical blueprint).
  • Enclosed by a nuclear membrane with pores.
  • Human cells have 23 pairs of chromosomes which contain all the information necessary to direct the synthesis of more than 100,000 different proteins necessary for life.
  • Cell Division: a single cell divides by duplicating it's nucleus and then dividing into 2 new identical cells.

Chemical Environment's Influence on Cells

  • Chemical signals trigger gene expression, activating specific genes for cell division or protein production.
  • Tumors/cancers occur when cells lose control on growth and division.

Cell Specialization

  • Cells becoming specialized by activating specific genes is called differentiation.
  • Stem cells can become specialized if placed in the right environment.

Lysosomes and Peroxisomes

  • Lysosomes: contain enzymes to break down substances.
  • Peroxisomes: contain enzymes that breakdown toxic substances.

Protein Filaments

  • Support structures within the cytoplasm (cytoskeleton).
  • Maintain the cell's flexibility, shape and strength.

Microvilli, Cilia, and Flagella

  • Extensions of the plasma membrane.
  • Microvilli: increase surface area.
  • Cilia: act as sensors and move materials.
  • Flagella: propel the cell (sperm).

Microbial Cells

  • Microbes are part of the normal microbiome forming the natural flora.
  • Types:
    • Bacteria.
    • Viruses.
    • Fungi.
    • Protozea.
    • Archaea.
    • Helminths.
  • Helpful body system locations:
    • Gastrointestinal tract.
    • Integumentary system.
    • Oral cavity.
    • Respiratory tract.
    • Vagina.

Diffusion

  • Substances move from high to low concentration (concentration gradient).
  • Simple diffusion: molecules diffuse across the lipid portion of the plasma membrane.
  • Facilitated diffusion: molecules diffuse through carriers or channels.

Osmosis

  • Passive transport of water across a membrane.
  • Tonicity: solute concentration.
    • Isotonic: no net water movement.
    • Hypotonic: lower solute concentration.
    • Hypertonic: higher solute concentration.

Active Transport

  • Requires energy (ATP) to move substances against the concentration gradient using ion pumps.

Tissue Types: Epithelial Tissue

  • Forms sheets that line cavities and cover surfaces.
  • Cells are easily regenerated.
  • Attached to underlying connective tissue.
  • Classifications:
    • Shape: squamous, cuboidal, columnar.
    • Layers: simple, stratified.

Tissue Types: Connective Tissue

  • More abundant than any other tissue type that have variable ECM
  • Most abundant connective tissue is aerola or loose CT
  • Establish a structural framework for the body
  • Transport fluids and dissolved materials
  • Protect delicate organs
  • Support, surround, and interconnect other types of tissue
  • Store energy reserves, especially in the form of triglycerides
  • Defend the body from invading microorganisms
  • Features: sparse cells with extracellular matrix (protein fibers and ground substance).

Tissue Types: Muscle Tissue

  • Contracts to produce movement.
  • Types:
    • Skeletal muscle: attached to bones.
    • Smooth muscle tissue: found in walls of hollow organs.
    • Cardiac muscle: heart tissue.

Tissue Types: Nerve Tissue

  • Transmits electrical signals.
  • Made up of:
    • Neurons: conduct impulses.
    • Neuroglia: support neurons.

Membranes

  • Multicellular sheets separating organs and lining body cavities.
  • Types:
    • Mucous.
    • Synovial.
    • Serous.
    • Cutaneous (skin).
  • Goblet cells produce secretions to maintain moist surfaces and lubricate.

Skin Structure

  • Epidermis: outermost epithelial tissue layer.
  • Dermis: inner connective tissue layer.
  • Subcutaneous region: mostly adipose tissue.

Epidermis

  • Contains:
    • Keratinocytes: produce keratin.
    • Melanocytes: produce melanin.
    • Dendritic cells: activate the immune system.
    • Tactile epithelial cells: associated with sensory nerve endings.
  • Layers (from deepest to superficial):
    • Stratum basale.
    • Stratum spinosum.
    • Stratum granulosum.
    • Stratum lucidum (thick skin only).
    • Stratum corneum.

Dermis

  • Supports and adds strength and flexibility to the epidermis.
  • Well supplied with blood vessels, nerves, and lymphatic vessels.
  • Layers:
    • Papillary dermis: areolar connective tissue.
    • Reticular dermis: dense irregular connective tissue.

Skin Pigments

  • Melanin: reddish-yellow to brownish-black; produced by melanocytes.
  • Carotene: yellow-orange pigment.
  • Hemoglobin: pinkish hue in fair skin.

Hair and Nails

  • Epidermal appendages rooted in the dermis.
  • Hair (pili): flexible strands of dead keratinized cells.
  • Hair follicle: extends into the dermis.
    • Types: vellus hair and longer, coarser terminal hair.
  • Nails: protective coverings, the clear part of nail is technically known as the 'nail plate.

Skin Glands

  • Eccrine glands: abundant on palms, soles, and forehead; secrete sweat for cooling.
    • Composed of: approximately 3 million of these glands located in the body. Sweat produced is 99% water, with traces of salts, waste products.
  • Apocrine glands: found in axillary and anogenital areas; may act as pheromones.
    • Composed of: the sweat from apocrine glands contains the same components as the eccrine glands but it's the addition of fatty substances and proteins that makes the sweat from apocrine glands unique
  • Sebaceous glands: secrete sebum to lubricate hair and skin.
  • Ceruminous glands: cerumen (ear wax).
  • Mammary glands: milk.

Skin Functions: Protection

  • Barriers:
    • Chemical (e.g., melanin, dermicidin, fatty acids).
    • Physical/mechanical (e.g., continuity, keratin).
    • Biological (e.g., dendritic cells, macrophages).
      * Dendritic cells