Anatomy lecture
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Transcript of Anatomy lecture
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What is Anatomy?Anatomy (= morphology): study of body’s structurePhysiology: study of body’s functionStructure reflects Function!!! Structure reflects Function!!! Branches of Anatomy Gross: Large structures Surface: Landmarks Microscopic: Cells and Tissues Developmental: Structures change through life Embryology: Structures form and develop before birth
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Hierarchy of the Body Moleculesmade of chemicals (4 macromolecules in body) carbohydrates, lipids, proteins, nucleic acids
Cellsmade of molecules cells and organelles
Tissuemade of cells epithelial, connective, muscular, nervous
Organsmade of tissues made of >1 type of tissue
Systemsmade of organs 11 systems in human body
Organismsmade of systemsPg 3
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Anatomical DirectionsAnatomical positionRegions Axial vs. Appendicular
Anatomical Directions-It’s all Relative! Anterior (ventral) vs. Posterior (dorsal) Medial vs. Lateral Superior (cranial) vs. Inferior (caudal) Superficial vs. Deep Proximal vs. Distal
Anatomical Planes Frontal = Coronal Transverse = Horizontal = Cross Section SagittalPg 6
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Embryology: growth and development
of the body before birth38 weeks from conception to birthPrenatal period Embryonic: weeks 1-8 Fetal: weeks 9-38
Basic adult body plan shows by 2nd month Skin = epidermis, dermis Outer body wall=muscle, vertebral
column and spinal cord Body cavity and digestive tubes Kidney and gonads Limbs=skin, muscle, bone
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Weeks 5-8 and Fetal Period Second month, tadpole person Tail disappears Head enlarges Extremities form (day 28, limb buds appear) Eyes, nose, ears form Organs in placeFetal Period Rapid growth and maturation Organs grow and increase in complexity
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4 Types of Tissue
1)Epithelium2)Connective3)Muscle4)Nervous
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Tissues: groups of cells closely associated that have a similar structure and perform a related function
Four types of tissue Epithelial = covering/lining Connective = support Muscle = movement Nervous = controlMost organs contain all 4 typesTissue has non-living extracellular material between its cells
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EPITHELIAL TISSUE: sheets of cells cover a surface or line a cavity (tissue type #1)
Functions Protection Secretion Absorption Ion Transport Slippery Surface
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Characteristics of Epithelium
CellularitySpecialized ContactsPolarity Apical vs. Basal
Supported by Connective TissueAvascular, InnervatedRegenerative
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Classification of Epithelium-based on number of layers and cell shapeLayers Simple Stratified Psuedostratified
Stratified layers characterized by shape of apical layerShapes Squamosal Cuboidal Columnar Transitional Pg 71
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Can You Identify the Classes of Epithelium?
A BC
D
EQuiz!!
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Features of Apical Surface of Epithelium
Microvilli: (ex) in small intestine Finger-like extensions of the plasma
membrane of apical epithelial cell Increase surface area for absorptionCilia: (ex) respiratory tubes Whip-like, motile extensions Moves mucus, etc. over epithelial surface
1-wayFlagella: (ex) spermatoza Extra long cilia Moves cell
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Features of Lateral Surface of Epithelium
Cells are connected to neighboring cells via: Proteins-link cells together, interdigitate Contour of cells-wavy contour fits together Cell Junctions
Desmosomes-adhesive spots on lateral sides Tight Junctions-at apical area, plasma
membrane of adjacent cells fuse, nothing passes
Gap junction-spot-like junction occurring anywhere, lets small molecules pass
www.smso.net Pg 80
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Features of the Basal Surface of Epithelium
Basement membrane = Sheet between the epithelial and connective tissue layers Attaches epithelium to connective tissue below Basal lamina: thin, non-cellular, supportive sheet
Made of proteins Superficial layer Acts as a selective filter Assists epithelial cell regeneration by moving new cells
Reticular fiber layer Deeper layer Support
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Name that Epithelial Feature!
(name and location on cell)
CiliaTight junctionMicrovilliBasement membrane
2
3
4
13
1
2
4
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Glands: epithelial cells that make and secrete a water-based substanceExocrine Glands Secrete substance onto
body surface or into body cavity
Have ducts Unicellular (goblet cells) or
Multicellular (tubular, alveolar, tubuloalveolar)
(ex) salivary, mammary, pancreas, liver
Goblet cell in small intestine
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Glands: epithelial cells that make and secrete a water-based substanceEndocrine Glands Secrete product into blood stream Either stored in secretory cells or in follicle
surrounded by secretory cells Hormones travel to target organ to
increase response No ducts
Thyroid gland: hormone in follicles ( F ) released into capillaries ( C )
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4 Types of Connective Tissue
1) Connective Tissue Proper
2) Cartilage3) Bone Tissue4) Blood
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Connective Tissue (CT): most abundant and diverse tissue
(tissue type #2)
Four Classes Functions include connecting, storing & carrying nutrients, protection, fight infection CT contains large amounts of non-living extracellular matrix Some types vascularized All CT originates from mesenchyme
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1) Connective Tissue Proper
Two kinds: Loose CT & Dense CTPrototype: Loose Areolar Tissue Underneath epithelial tissue Functions
Support and bind to other tissue Hold body fluids Defends against infection Stores nutrients as fat
Each function performed by different kind of fiber in tissue
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Fibers in Connective TissueFibers For Support Reticular: form networks for structure &
support (ex) cover capillaries Collagen: strongest, most numerous,
provide tensile strength (ex) dominant fiber in ligaments Elastic: long + thin, stretch and retain shape (ex) dominant fiber in elastic cartilage
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In Connective Tissue ProperFibroblasts: cells that produce all types of fibers in CT, produce + secrete protein subunits to make themInterstitial (Tissue) Fluid: derived from blood in CT proper; medium for nutrients, waste + oxygen to travel to cells; found in ground matrixGround Matrix (substance): part of extra-cellular material that holds and absorbs interstitial fluid, jelly-like with sugar & protein molecules
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Defense from Infection Areolar tissue below epithelium is body’s first defenseCells travel to CT in blood Macrophages-eat foreign particles Plasma cells-secrete antibodies, mark molecules
for destruction Mast cells-contain chemical mediators for
inflammation response White Blood Cells = neutrophils, lymphocytes,
eosinophils-fight infectionGround substance + cell fibers-slow invading microorganisms
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Specialized Loose CT ProperAdipose tissue-loaded with fat cells, highly vascularized, high metabolic activity
(eg) in hypodermis under skinReticular CT-contains only reticular fibers Forms caverns to hold free cells
(eg) bone marrow, holds blood cells Forms internal “skeleton” of some organs
(eg) lymph nodes, spleen
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Dense/Fibrous Connective Tissue
Contains more collagen Can resist extremely strong pulling forcesRegular vs. Irregular Regular-fibers run same direction, parallel to
pull (eg) fascia, tendons, ligaments
Irregular-fibers thicker, run in different directions (eg) dermis, fibrous capsules at ends of bones
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Components of CT Proper Summarized
Cells Matrix
Fibroblasts Gel-like ground substance
Defense cells
Collagen fibersReticular fibersElastic fibers
Fat cells
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2) CartilageChondrocytes produce cartilage tissueMore abundant in embryo than adultFirm, FlexibleResists compression (eg) trachea, meniscus
80% waterAvascular, NOT InnervatedPerichondrium-dense, irregular connective tissue around cartilage growth/repair of cartilage resists expansion during compression of
cartilage
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Cartilage in the Body
Three types: Hyaline
most abundant fibrils in matrix support via flexibility/resilience (eg) at limb joints, ribs, nose
Elastic many elastic fibers in matrix
too great flexibility (eg) external ear, epiglottis
Fibrocartilage resists both compression and
tension (eg) meniscus, annulus fibrosus
Pg 125
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Components of Cartilage Summarized
Cells Matrix
Chondrocytes Gel-like ground substance
Chondroblasts(in growing cartilage)
Lots of water
Some have collagen and elastic fibers
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3) Bone Tissue:(a bone is an organ)
Well-vascularized Function: support (eg) pelvic bowl, legs protect (eg) skull, vertebrae mineral storage (eg) calcium, phosphate (inorganic
component) movement (eg) walk, grasp objects blood-cell formation (eg) red bone marrow
Osteoblasts: secrete organic part of bone matrixOsteocytes: mature bone cells, maintain bone matrixPeriosteum: external layer of CT surrounds boneEndosteum: internal layer of CT lines cavities and covers trabeculae
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Compact bone: dense, external layer Haversian system = osteon
long, cylindrical structures run parallel to long axis of bone within each osteon, groups of concentric tubes (lamella) Lamella: layer of bone matrix all fibers run in same direction fibers on each lamella runs in opposite directions to one near it Haversian canal-runs through center of osteon, contain blood
vessels and nerves
Bone Anatomy: Compact bonePg 128
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Haversian System = Osteon
lamella
osteon
Pg 131
Pg 132
lamella
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Spongy bone (cancellous bone): internal layer Trabeculae: small, needle-like pieces of bone
form honeycomb each made of several layers of lamellae + osteocytes no canal for vessels space filled with bone marrow not as dense, no direct stress at bone’s center
Bone Anatomy: Spongy bone
Pg 136
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12
3
4
Spongy BoneCompact Bone
LamellaHaversian canal
2 1
3 4
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Components of Bone Tissue Summarized
Cells Matrix
Osteocytes Gel-like ground substance calcified with inorganic salts
Osteoblasts Collagen fibers
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4) Blood: Atypical Connective Tissue
Function: Transports waste, gases, nutrients,
hormones through cardiovascular system Helps regulate body temperature Protects body by fighting infectionDerived from mesenchymeHematopoiesis: production of blood cells Occurs in red bone marrow In adults, axial skeleton, girdles, proximal
epiphyses of humerus and femur
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Blood CellsErythrocytes: (RBC) small, oxygen-transporting
most abundant in bloodno organelles, filled w/hemoglobinpick up O2 at lungs, transport to rest of body
Platelets = Thrombocytes: fragments of cytoplasmplug small tears in vessel walls, initiates clotting
Leukocytes: (WBC) complete cells , 5 typesfight against infectious microorganisms stored in bone marrow for emergencies
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Components of Blood SummarizedCells Matrix
Erythrocytes (red blood cells)
Plasma (liquid matrix)
Leukocytes(white blood cells)
NO fibers
Platelets
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Muscle Tissue (tissue type #3)
Muscle cells/fibers Elongated Contain many myofilaments: Actin & Myosin FUNCTION Movement Maintenance of posture Joint Stabilization Heat Generation Three types: Skeletal, Cardiac, Smooth
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Skeletal Muscle Tissue(each skeletal muscle is an organ)
Cells Long and cylindrical, in bundles Multinucleate Obvious Striations
Skeletal Muscles-VoluntaryConnective Tissue Components: Endomysium-surrounds fibers Perimysium-surrounds bundles Epimysium-surrounds the muscle
Attached to bones, fascia, skinOrigin & Insertion
pg 235
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Cardiac MuscleCells Branching, chains of cells Single or Binucleated Striations Connected by Intercalated
discsCardiac Muscle-InvoluntaryMyocardium-heart muscle Pumps blood through vessels
Connective Tissue Component Endomysium: surrounding cells
Pg 244
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Smooth Muscle Tissue
CellsSingle cells, uninucleateNo striations
Smooth Muscle-Involuntary2 layers-opposite orientation (peristalsis)
Lines hollow organs, blood vesselsConnective Tissue Component
Endomysium: surrounds cells
Pg 246
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Nervous Tissue: control
Neurons: specialized nerve cells Cell body, dendrite, axon
Interneuron: between motor & sensory neuron in CNS Support cells (= Glial): nourishment, insulation, protection Satellite cells-surround cell bodies within
ganglia Schwann cells-surround axons Microglia-phagocytes Oligodendrocytes-produce myelin sheaths
around axons Ependymal cells-line brain/spinal cord,
ciliated,help circulate CSFBrain, spinal cord, nerves
PNS
CNS
pg 322
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Neuronal Anatomy
Synapse: cell junction where neurons communicateOne direction: presynaptic neuron, postsynaptic neuronPresynaptic neuron
Synaptic vesicles fuses w/presynaptic membrane
Neurotransmitters released, diffuse across synaptic cleft, bind to postsynaptic membrane ٠Creates impulse (action potential) in that neuron
٠Cycle repeats
pg 325
www.smso.net“May I please be excused? My brain is full!!”
