Exam Study Notes

Additional Notes: Tissue Organization & Cells

• Life Functions

  • Maintain boundaries (skin, mucosa)

  • Organization:

    • Movement

    • Responsiveness

    • Digestion

    • Metabolism

    • Excretion

    • Reproduction

    • Growth

  • Lining => epithelia

  • Interface => basal lamina

  • Support => connective (interface Fascia)

  • Muscle (smooth, cardiac, skeletal) => tube/layer/organ (muscle, bone, joints)

  • Nervous system, endocrine

    • (G.I. trace)

    • (tissues, liver)

    • (Urinary, GI)

    • (genitalia)

  • Cavity formation: Cranial, Dorsal, Vertebral, Mediastinal, Thoracic, Pericardial, Ventral, Pleural, Abdominal, Pelvic

  • Defined by Membranes

Homeostasis:

• Maintaining a consistent range.

• Receptor, Control center, effector

• Negative (-ve) & positive (+ve) feedback

Cells:

• Plasma membrane proteins:

  • Receptors

  • Transmembrane proteins

  • Channels/transporters

  • Adhesion molecules

  • Enzymes

  • Cell: Cell recognition

Intercellular Junctions

• Tight junctions

  • Zipperlike

  • Apical edge

  • Prevents paracellular diffusion.

• Gap Junctions

  • Transmembrane protein, lateral sides

  • Fluid-filled channel = ease of ion movement between cells.

• Desmosomes

  • Snap-like connections

  • Loose

  • Allows diffusion between cells.

• Hemidesmosomes

  • Attachment to basal lamina.

Cytoskeleton

• Microfilaments

  • Actin, FXN: Support (m), microvilli

• Intermediate filaments

  • Actin tetramers FXN: Cell strength

• Microtubules

  • Tubulin FXN: Move organelles, Chromatin

Membrane Transport

• Diffusion - Concentration/electrical gradient

• Passive transport - Channels/pores

• Active transport → transporters (ATP needed).

Tissues: Embryonic Tissues

• Ectoderm => nervous system, special senses, oral & anal mucosas \ Living (skin epidermis

• Mesoderm => Cardiovascular, Muscle, bone, adipose

• Endoderm => GI tract mucosa, Urogenital tract, respiratory.

Sections - Histology

• Planes through: Sagittal, Frontal, Transverse, Oblique, Longitudinal, Cross, Oblique

• Organs

Epithelia - Linings

• FXN: Protection, Secretion, absorption

• Simple = 1 layer thick

• Stratified = 2+ layers

• NOT VASCULARIZED

• Relies on diffusion of gases etc. through cell layers & interstitial fluid.

Simple Squamous

• Thin & flat

• Diffusion (blood vessels, alveoli)

• Secretory (serous)

Simple Cuboidal

• Secreted

• Absorb

• Kidneys, Acini

Simple Columnar

• Secrete

• Nuclei basal

• Stomach, GI tract.

Keratinized Stratified Squamous

• Keratin - filled

• Upper layers

• Waterproof

• Dead

• FXN: Epidermis

Pseudo stratified Columnar (Ciliate)

• Secrete & propel

• Mucous

• Trachea, epididymis

Non-Keratinized Stratified Squamous

• Moist, slippery

• FXN: vagina, oral mucosa, cornea, anus, tongue, esophagus.

Stratified Cuboidal

• Sweat, sperm

• Hormones

• Uterus, male urethra

Stratified Columnar

Transitional Epithelia

• Round-flat when stretched

• Ureter, bladder

Glands - Classified by Structure or Secretion.

• Exocrine - To outside the body/tissue e.g. Sweat, gastric, sebaceous.

• Endocrine - Into blood stream.

Exocrine Glands

• Serous - Thin, watery

• Mucous - Mucus, mucin-rich

• Cytogenic - Release whole cells.

• Holocrine - Cells disintegrate to make secretion.

• Merocrine - Product released via exocytosis (sweat).

• Apocrine - Modified mesocrine, mammary glands.

Connective Tissues: Ground Substance

• Layer of adhesive proteins between tissue types.

  • Laminin - adhesive, e.g., between epithelia & connective tissue.

  • Proteoglycans - bonds Cells & extracellular matrix (ECM)

  • Fibrillin - adhesive

  • Glycosaminoglycans (GAGS) - attract H2O, hold H2O, maintain osmolarity

Connective Tissue Types

• Fibroblasts

  • Loose connective

    • Areolar (Underline epithelia

    • Between muscle

    • Reticular (Lymph nodes)

    • Adipose Red bone marrow

  • Dense connective

    • Regular (tendons, Ligaments)

    • Irregular (e.g. dermis)

• Chondroblast - Cartilage

  • Hyaline (trachea)

  • Elastic (Pinna)

  • Fibro- (Symphysis)

• Osteoblast - Bone

  • Compact

  • Spongy

• Hemopoietic Stem Cell - All formed elements of blood (Red, white & platelets)

Wound Healing

• Scab, artery, capillary, WBC

• Inflammation

  • Swelling, redness, heat, pain

  • Edema contains pathogen, stabilizes injury

  • Redness & heat from vasodilation

    • Bring nutrients & O_2 for healing

    • Remove debris/wastes

  • WBC to eliminate pathogen

  • Pain stops you injuring further

• Regenerating epithelium (calls divide & migrate in)

• Vascular supply.

• Fibroblasts migrate in & deposit collagen.

• Macrophages remove debris - granulation tissue.

• Organization

  • Regenerated epithelium

  • Fibrosed area matures & Contracts (can take months)

  • Epithelium thickens

• Regeneration

• Scarring

  • Erythematous - Fed from neovascularization

  • Hypertrophic - Over growth that reduces with time.

  • Atrophic - Indented.

Nerves

• Cell body with long projections (axons, dendrites).

• Peripheral nerves can regenerate if cell body remains intact, cannot divide

Muscle

• Smooth

• Cardiac & striated, cardiac has intercalated discs.

• Skeletal.

Tissue Growth

• Hypertrophy = ↑ cell size, rarely cell #

• Atrophy = ↓ cell size or cell #

Skin, Hair, Nails

• Skin

  • Epidermis

  • Stratum corneum-Keratinized outer layer-waterproofing

  • Stratum lucidum-thick skin only

  • Stratum granulosum-Keratinohyalin

  • Stratum spinosum-Keratinocytes

  • Stratum basale-stem cells (keratinocyte melanocytes pigment-touch receptors)

  • Dermis

    • Dense irregular CT- nerves, blood vessels, hair follicles sweat & sebaceous glands

  • Hypodermis

    • Adipose-larger blood vessels

  • Stratum basale divides pushing Cells up. cells gradually filled with Keratin & lose Cell function until completely dead. Dead cells exfoliated.

Hair

• Fibrous Sheath

• Shaft

  • Circular shaft = straight

  • Oval shaft = curly.

• Pigment

  • Eumelanin = brown/black.

  • Pheomelanin = yellow

  • Medulla (balance of both

  • Cortex (pigmented) - shades) -tighter curl).

• Inner root sheath.

• Outer root sheath.

• Papilla - for proper hair growth the papilla MUST be intact, & hair follicle straight to guide hair through epidermis. No papilla = NO HAIR

• Growth

  • Anagen - active growth

  • Catagen - shrinking follicle - hair separates from papilla. (2-3 wks)

  • Telogen - resting (1-3 mnths) No growth - bulb & papilla reconnect

• Blocked follicle == ingrown hair.

Nail

• Fold

• Root

• Free edge.

• Nail bed.

• Stem cells in Nail bed - as cells pushed out, Keratin added - nail bed adds Keratin = thickens nails.

• Nails & sensitivity of touch receptors to pressure by providing resistance

Bone

• Long, short, flat, irregular shaped.

• Epiphysis, metaphysis (growth / epiphyseal Plate - ONE END, ONLY., diaphysis (shaft)

• Cartilage spongy Bone with red bone marrow compact bone periosteum. Yellow bone marrow endosteum

Flat Bone

• Periosteum outer compact bone spongy bone + red bone marrow. Holes = trabeculae. Inner compact bone.

Bone Cells

• Osteogenic cells

• Osteoblasts

• Osteocytes

• Osteoclasts

  • 3-50 fused stem cells.

  • Lie under periosteum

  • Ruffled border- H^+ pumped into space between ruffled border & bone - Ca^{2+} follows = dissolves Minerals, acid phosphatase digests collagen - NEEDS ACID TO WORK

Compact Bone

• In endosteum, periosteum, Central canals => osteoblasts mineralize matrix using osteonectin & Ca^{2+} & PO_4^{2-}

• Osteoblasts trapped in matrix - Lacunae (hole cell in) cells connected by gap junctions in projections = Canaliculi

Osteon

• Canaliculi

• Perforating / Volkmann Canals - Canals turning perpendicular to central canal for blood vessels - blood vessels, nerves

• Central osteocyte canal - growth of osteon OUTSIDE IN.

Intramembranous Ossification

• Flat bones - FROM SCRATCH

  • Mesenchyme condenses into trabeculae

  • Osteoblasts lay down matrix

  • Hydroxyapatite deposited

  • Osteoclasts carve out marrow cavities, blood vessels grow into hiles/cavities

  • Osteoblasts form compact bone at surfaces

  • Formation of periosteum.

Endochondral Ossification

• Other bone types - uses hyaline cartilage as scaffold

• Perichondrium -> BV -> Osteoblasts -> Bony collar -> 1° Ossification Center (1°OC) in middle -> vascularization, chondrocytes swell & die

• 2° Ossification Center (2°OC) epiphysis Meta-/Diaphysis articular Cartilage, spongy bone EP Plate Enlarge marrow cavity

• Birth -> enlarged marrow Cavities - enlarging, chondrocytes swell & die 2°OC cavities in one epiphysis

• Epiphyseal Plate Growth

  • Resting Zone - Reserve Cartilage

  • Proliferating Zone - Chondrocytes dividing

  • Degenerating Zone - older chondrocytes - older chondrocytes (hypertrophy & enlarged)

  • Ossification Zone - adding moss hydroxyappatite, Fully mineralized. Simulate osteoclasts prepare surface- osteoblasts replace bone, - Cover with lining calls

Bone Remodelling

• Wolff's Law

  • Resorption

  • Reversal

  • Formation

  • Resting

  • Cartilage Fully mineralized.

Control of Calcium - Hormonal

• Calcitonin - Influence osteoblasts to deposit hydroxyapatite, & CaCO_3 - Ca^{2+} out from plasmic.

• Calcitriol - activated Vitamin D UV light -> cholecalciferol D_3 -> LIVER -> calcidiol -> KIDNEY -> Calcitriol ↑ Ca^{2+} absorption in GI & from bone, stem cell differentiation to OSTEOCLASTS, rescrption of Ca^{2+} in Kidney.

• Parathyroid Hormone (PTH) - ↑ Ca^{2+} in serum. Causes RANKL release from Osteoblast to ↑ Osteoclast number - ↑ Ca^{2+} resorption & Calcitriol production -& Collagen synthesis by osteoblasts.

Fractures

• Hematoma Formation - Hematoma (granulation tissue)

• Soft Callus Formation - Soft callus - fibrocartilage

• Hard Callus Formation - Ossification of Gibro-cartilage by OSTEOBLASTS, spongy bone/hard callus

• Remodelling - spongy bone -> Compact bone by osteoblasts, Gradients removed by osteoclasts continuous marrow cavity.

Joints: Structural Classification

• Bone ends

• 1) Bony - Fusion of bones e.g. Frontal bones (Synostosis)

• 2) Fibrous - Fibers connect bones e.g. SUTURES (serrate, lap, plane)

• 3) Cartilaginous - Castilage forms joint.

  • Hyaline cartilage ribs to sternum (Synchondrosis)

  • Fibro cartilage - Pubic symphysis (semiphysis), Intervertebral discs.

• 4) Synovial - Synovial Membrane LIGAMENT attach bone to bone.

  • Joint cavity filled with synovial fluid - lubrication, feeds cartilage.

  • Fibrous capsule continuous with periosteum

  • Synovial membrane Subintima - Loose areolar/ Gatty/fibrous, Intima -Fibroblasts secrete HYALURONAN & LUBRICIN - macrophages remove debris from Synovium Underneath HIGHLY VASCULAR.
    Functional Classification - How much movement exists.

Synarthrotic

• Synostosis (bony) - Fused bone - NO MOVEMENT (or very little over time).

• Gomphoses - Teeth jaw

• Syndesmoses - e.g. Tibia fibula.

• Sutures

• Synchondrosis - rib to sternum

Amphiarthrotic

• Semiphysis - pubic symphysis - SOME MOVEMENT

Synovial Joints

• Ball & socket (Hip)

• Hinge (elbow)

• Saddle (Thumb)

• Gliding (Intercarpel)

• Pivot (ulnaradial)

• Condyloid (Metacarpale

Tendons & Bursae

• Extension of joint capsule connective tissue lined it synovial membrane around tendons so easily slide over muscle to bone. individual tendons.

Levers

• Mechanical advantage - MA = \frac{Length :of: effort: arm}{Length: of: resistance: arm}

  • MA => 1 low advantage effort

    • How much effort goes in alters how easily you you get moving

    • Low power, high speed moving e.g. bicep /brachialis -forearm (elbow joint).

  • MA < 1 high advantage low speed

    • High power, e.g: Temporalis (TMJ)-mylohyoid-digastrics, Atlantooccipital joint e.g. TMJ opening & closing.

• 1st class Lever - fulcrum in middle

• 2nd Class Lever - Effort in the middle/Ulna/humerus

• 3rd class lever - Effort is farthest from the movement/bone

• Tendon (Insertion) attachment of muscle to the bone that MOVES

Deep Fascia

• Continuation of tendon around whole belly

• Epimysium - around bundles of cells.

• Perimysium - around bundles of cells.

• Endomysium - around individual cells.

Attachment of Muscle

• Origin - attachment of muscle to bone that DOES NOT MOVE.

• Belly - Thickest part of muscle

• Agonist/Prime mover - Muscle putting in initial effort to move bone, contributes most effort.

• Synergist - Aids agonist in completing movement

• Antagonist - Works in opposition to agonist.

• Fixator - Stabilizes bone & joint.

Microscopic Anatomy

• T-tubule, sarcoplasmic reticulum, mitochondria, H band, Z disc - Sarcomere, Actin, I band, myosin

• Titin - actin-tropomyosin-troponin- myosin head

  • A band - thick filament region

  • I band - thin filament region

Motor Units

• Nerve (1) and the number of muscle fibers it innervates

  • Fine motor

    • A few fibers (nerve more innervation - conscious thought, longer to learn).

  • Gross motor

    • Many fibers (1000's) less innervation required.
      (8) Neuromuscular Junction (NMJ) Mitochondria, synaptic cleft, neurolemma, Ca channel, Synaptic knob sarcolemma (continuous with motor end plate membrane), K* channel, ACh acetylcholine receptors (AChR)

• Electrical signal reaches Synaptic knot, Ca^{2+} Channels OPEN, Ca^{2+} INFLUX

• Ach Released into cleft, Ach binds receptor Recepter opens its Channel, Na^{+}:IN :K^+:OUT End Plate Potential (EPP) - Na^+ :K^+ diffuses beneath muscle cell membrane -↑ Voltage as it goes. Voltage opens Na^+ channels

• IN = DEPOLARIZE, : K^+ :channels: open = REPOLARIZE Action potential (AP) moves across muscle cell, down T-Tubules, opens Voltage operated Ca^{2+} Channels (SARCOPLASMIC RETICULUM) -Ca^{2+} binds TROPONIN - TROPOMYOSIN Changes Shape => OPENS UP ACTIVE SITE ON ACTIN

Muscle Contraction

• Hydrolysis of ATP-cock of myosin head-powerstroke

• Cross Bridge with ACTIN - LOCK

• Myosin head binds more ATP, Releases actin to cock again for further binding then cross bridging

Relaxation: Muscle Contraction

• Nerve impulses to Synapse (NICE) stop, ACh released from ACGR (disperses from Synapse, cleaved into Acetic Acid & CHOLINE by AChE
  (ACETYLCHOLINESTERASE) Channel CLOSES, NO EPP,Cast release stops

• Ca^{2+} returned to sarcoplasmic Reticulum via ATP operated pump- No Ca^{2+} = troponin Returns to initial position

Length-Tension Relationship

• If a muscle is too contracted already, it is not able to shorten, if strained too far already not efficient

• Stimulus - latent period, contraction period, relaxation period Single twitch does NEE define all work- Single Threshold Stimulus => switches, until maximum tension is achieved

• Max Contraction voltage Twitch responses- Incomplete tetany Treppe Twitch Low stimuli infrequent Muscle does not contract fully, contraction voltage each twitch- Recruit Motor Units in the motor unit.

Responses to Muscle Stimulation

• Incomplete Tetany - Each stimulus cycles before recovery sustained fluttering contraction

• Temporal summation, Tetanus NO relaxation time Smooth prolonged Contraction - Locked muscle.

• Isometric - Tense muscle - NO CHANGE IN LENGTH.

• Isotonic - Tension DURING Contraction & relaxation MUSCLE CHANGES LENGTH

Fatigue & ATP Production

• At the start: Phosphagen system --> Aerobic respiration --> glycogen-lactic acid system --->finish
  Myoglobin -> Creatine system-> ADP (myokinase) -->ADP(creatine kinase) --> glycogen

• Phosphagen System

  • Supported by Cardiovascular changes (↑HR, RR, vasodilation), Provides O_2 in muscle for short spurts no longer than 10 sec.

• Glycogen-Lactic Acid System

  • Anaerobic respiration, prolonged exercise - ↓ rate, vasodilation, respiration rate => ↑ O_2 to muscles.

• Glycogen - depletion of Glucose, fluid & electrolyte loss - ATP Synthesis &, Na^+/K^+ pump cannot maintain membrane, - lactic acid inhibits enzymes hyperpolarizes cell.

Oxygen Debt

• Replace O2 supplies & reserves (myoglobin, Hb, plasma O2

• Replenish phosphagen system.

• Convert lactic acid glucose

• ↑ metabolism from ↑ body. temp; Co exhaling CO_2 (to balance pH).

Muscle Fiber Types

• Slow-Twitch Fibers (Type I)- Sustained aerobic -↑ mitochondria, myoglobin, capillaries -resistant to fatigue (Endurance Athletes)

• Fast-Twitch Fibers (Type IIx) Short anaerobic bursts - ↑ glycogen/lactic acid supplies & quicker Ca^{2+} release from SR - have fewer & Quicker Ca^{2+} release from SR. (Strength athletes/sprinters)

• Shape & size of muscle dependent

  • Length of muscle at start of contraction

  • Shape (think dienst vs. giant).

  • Size of motor unit & recruitment gross motor muscles easier to influence in terms of strength