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Animal structure and function
Tissues
EpithelialConnectiveMuscleNervous
Epithelial tissue
Epithelial tissue (epithelium):Covers all surfaces of the bodyEpidermis (ectoderm): Outer portion of skinEndoderm:Lining of inner surfaces of digestive tract Mesoderm:Inner surface of body cavities
Epithelial tissue
Closely packedTight junctionsOne/or few cell layers thickSelective absorption in the intestinesRapid gas exchange in lungsProtection from microbes, water loss
Epithelial tissue
Regenerative capabilitiesLiver (gland from epithelial tissues)Epidermis every 2 weeksStomach lining every 2-3 days
Epithelial tissue
TypesBased on cell thicknessShape on exposed surfaceSimpleOne layer thickStratifiedMultiple layers of cells
Epithelial tissue
Shapes of cells Cuboidal:As wide as they are tall (like dice) Columnar:Taller than wide (like bricks on end) Squamous Flat like floor tiles
Epithelial tissues
Epithelial tissue
Simple squamous Lining of lungs, capillary walls and blood vesselsSimple cuboidal Lining of some glandsSimple columnar Lining of stomach, intestines and parts of respiratory tract
Epithelial tissue
Stratified squamous Outer layer of skin and mouthKeratin Water resistant protein
Epithelial tissue
Exocrine glands (duct system)Duct:Connection from gland to tissueSecrete/absorb chemical solutionsSweat and sebaceous glandsLining of intestines & lungs that secrete mucous
Epithelial tissue
Endocrine glands (ductless glands)HormonesSecreted into blood stream
Glands
Connective tissue
Holds tissues & organs togetherDerived from mesodermLoosely packed cellsScattered in an extracellular matrix
Connective tissue
Matrix: Composed of a web of fibers In a foundation of liquid, jellylike or solidFibers (proteins) are collagen, elastic, or reticular
Connective tissue
Collagen:Non-elastic-doesn’t tear easilyElastic:Makes tissue elasticElastin (protein)Reticular:Thin, branched, joins connective tissue to adjacent tissues
Connective tissue
Cells in matrixFibroblasts: Produce & secrete extracellular matrixMacrophages:Engulf foreign bodies & debrisMast cells & heparin
Connective tissue types
1. Loose connective tissueBeneath skin & between organsSupport, insulation, food storageAdipose tissue (fat)Cells become larger when gain weightShrink with weight loss
Connective tissue
2. Dense connective tissueTendons, ligaments, sheath around organs (periosteum), dermis of skinSupport, strong connections3. Special connective tissueCartilage, bone, blood,
Connective tissue
Special connective tissue
Cartilage Consists of chondroitin (glycoprotein) & collagenStrong, flexible tissue, absorb stressJoints, ear pinna, nose, intervertebral discs, larynxChondrocytes: Cartilage cells
Cartilage
Bone
Embryos---more cartilageCartilage is replaced with bone cells or osteocytesMatrix hardens with crystals of calcium phosphate mixed with collagen
Bone
Osteoblasts: Lay down new boneOsteoclasts: Dissolve boneOsteons: Unit of bone structureContains calcified matrix, osteocytes, nerve fibers, blood vessels
Bone
Flat bonesLong bonesSpongy bone: Contains marrowBlood cells formedCompact bone:More dense, gives strength
Bone
Bone
Blood
Plasma (matrix)CellsRBC (erythrocytes)Contain hemoglobin (carries oxygen)WBC (leukocytes)Neutrophils, eosinophils, basophils, lymphocytes, monocytesPlatelets (thrombocytes)
Blood
Blood
Plasma containsWastes, nourishmentHormonesNa+, Ca2+, other ionsFibrinogen, albumin, antibodies
Muscle tissue
MovementOrganization of actin & myosin filamentsSmooth, skeletal & cardiac musclesStriated muscles: skeletal & cardiacSkeletal muscles: voluntary controlSmooth & cardiac muscles: involuntary control
Muscle tissue
Smooth muscle Walls of blood vessels, stomach, intestinesViscera: Internal organsMade of sheets of cells each with a single nucleus
Muscle tissue
Skeletal muscleAttached by tendons to bonesContract move bones
Muscle tissue
Muscle tissue
Cardiac muscleSmall interconnected cellsLinked by gap junctionsOpenings allow small substances & electrical charges to pass between cellsMyocardium Single functioning units
Nerve tissue
NeuronsCell body, dendrites, axon Neuroglia Supporting cellsInsulate neuronsEliminate foreign bodies
Nerve tissue
DentritesThin, branched extensions Receive impulsesAxonsSingle extension of cell bodyCarries impulse awayMyelin sheaths, insulating cover
Neurons
Neurons
Sensory neuronsEye,ears, surface of skinMotor neuronsBrain & spinal cordInterneuronsBrain & spinal cordNeurons within the CNS
Neurons
Summary
Epithelial tissuesSimple or stratifiedCuboidal, columnar, squamousConnective tissuesLoosely packed, tightly packedSpecial (bone, cartilage, blood)Matrix
Summary
Muscle tissuesSmooth, cardiac, skeletalNerve tissues:Neurons (cell body, dentrites, axons)Sensory, motor and interneurons
Coordination
HormonesNervous systemHomeostasis
Homeostasis
Dynamic constancy of internal environmentDynamic because conditions fluctuate Narrow rangepHTempGlucoseOxygen
Regulation
1. Negative feedback loops2. Positive feedback loops
Negative feedback
media\40_08NegativeFeedback_A.html
Positive feedback
media\40_08PositiveFeedback_A.html
Negative feedback loops
SensorsMeasure internal environmentIntegrating centerReceives information from sensorsCompares to normal rangeResponds
Negative feedback loops
Effectors:Muscles or glandsReceive information from centerResponse
Negative feedback loops
Temperature increaseHypothalamus senses deviationSends signals to relieve heatSweating & vasodilationReach baseline Negative feedback stops response
Negative feedback loops
Temperature decreaseHypothalamus sends signalsShiver, vasoconstrictionTemp to baseline Negative feedback stops response
Thermoregulation
Fig. 40-9
(a) A walrus, an endotherm
(b) A lizard, an ectotherm
Negative feedback loops
Glucose (eat a meal)Elevated blood levelIslets of Langerhans (sensor, center)InsulinLowers blood sugar (uptake in muscle, fat & liver cells)Negative feedback stops insulin release
Positive feedback loops
Uterine contractionsPressure from baby on uterusCauses contractionsCauses more stretchingMore contractionsContinues until birth
Positive feedback loop
Blood clottingClotting factors stimulate the formation of more factorsClot formsMaintain blood volume
Bioenergetics
Overall flow & transformation of energy in an animalDetermines nutritional needsAnimal size, activity and environment
Fig. 40-17
Organic moleculesin foodExternal
environment
Animalbody Digestion and
absorption
Nutrient moleculesin body cells
Carbonskeletons
Cellularrespiration
ATP
Heat
Energy lostin feces
Energy lost innitrogenouswaste
Heat
Biosynthesis
Heat
Heat
Cellularwork
Metabolic rate
Amount of energy an animal uses in a unit of timeTorpor:Physiological state of low activity with low metabolismHibernation:Long term torpor