Animal Structure and Function

Functional Anatomy

• Animal adaptations evolved through time by natural selection.

• Can also adapt over short periods of time.

• Chemical energy needed for searching for food, generating body heat, regulating internal temperature, etc..

http://www.no-pest.com/CruisinForaBruisin'.JPG

• Bioenergetics - how organisms obtain, process, and use their energy resources.

• All animals have correlation between form (anatomy) and function (physiology).

http://shs.westport.k12.ct.us/mjvl/anatomy/jugglers.gif

• Tissues make up organs, organs organ systems organisms.

• Tissues - groups of cells with common structure and function.

• 4 types of tissues: epithelial, connective, muscle, nervous.

http://www.emc.maricopa.edu/faculty/farabee/biobk/stomTS.gif

• 1Epithelial – covers body, lines organs and cavities in body.

• Cells joined tightly together.

• Prevents fluid loss, invasion of microorganisms.

• Attached to underlying tissue by basement membrane.

http://www.uoguelph.ca/zoology/devobio/miller/01362fig6-1.gif

• ASimple epithelium – single-layered.

• BStratified – multi-layered.

• Shapes – cuboidal, columnar, sqamous (flattened)

• Glandular – secretes fluid – can line respiratory system (produces mucous)

• 2Connective tissue – binds, supports other tissue.

• Cells scattered throughout matrix.

• Matrix made of fibers.

• 3 types of fibers – 1collagenous (collagen – tough), 2elastic (elastin, flexible), 3reticular (thin and branched – connect to adjoining tissues)

http://www.mhhe.com/biosci/ap/histology_mh/reticct.jpg

Reticular fibers

• Major types - loose connective tissue, adipose tissue, fibrous connective tissue, cartilage, bone, and blood.

• ALoose connective - packing materials, holding organs in place.

• 2 cell types – 1Fibroblasts (secrete proteins), 2Macrophages (engulf bacteria)

http://www.sci.sdsu.edu/histology/hi_res/jpg/ct01oh.jpg

• BAdipose - insulates body, stores fuel as fat molecules.

• Contains large fat droplet that swells when fat is stored, shrinks when body uses fat as fuel.

http://www.deltagen.com/target/histologyatlas/atlas_files/musculoskeletal/adipose_tissue_white_40x.jpg

• CFibrous connective - forms tendons (muscles to bones) and ligaments (bones to bones at joints)

• DCartilage - flexible supports in certain locations, such as the nose, ears, and vertebral disks.

• Chondrocytes secrete collagen.

http://www.mhhe.com/biosci/ap/histology_mh/hcart.jpg

• EBone - mineralized connective tissue.

• Osteoblasts deposit a matrix of collagen.

• Bones consists of repeating units called osteons – has nerves and blood vessels.

http://www.texarkanacollege.edu/~mstorey/1407/bone.jpg

• FBlood - matrix liquid (plasma) has water, salts, variety of dissolved proteins.

• Suspended in plasma erythrocytes (red blood cells – carry oxygen), leukocytes (white blood cells – fight invaders) cell fragments (platelets – clotting)

http://www.kumc.edu/instruction/medicine/anatomy/histoweb/blood/large/Blood000.JPG

• 3Nervous - senses stimuli, transmits signals from one part of animal to another; functional unit – neuron

• Consists of cell body, 2+ extensions (dendrites + axons)

• Dendrites transmit nerve impulses from tips toward rest of neuron.

• Axons impulses toward another neuron or effector (muscle cell)

• 4Muscle – composed of muscle fibers capable of contracting when stimulated by nerve impulses.

• Fibers consist of contractile proteins actin and myosin.

• 3 types – skeletal, cardiac, smooth.

• ASkeletal – responsible for voluntary movement; striated.

• BSmooth – no striations; found in walls of digestive tract, urinary bladder, arteries, other internal organs – involuntary.

• CCardiac – striated and branched; forms walls of heart muscle. Cells joined by intercalated discs; involuntary.

http://www.lima.ohio-state.edu/academics/biology/images/anatomy/Smooth%20Muscle%20400X.jpg

Functional Anatomy

• Tissues organized into organs.

• Mammals – thoracic cavity – lungs, heart – separated from abdomen by diaphragm.

• Tissues can be arranged in layers.

• Organ systems carry out major body functions.

Body Plans

• Animal’s size and shape - body plans.

• Physical requirements constrain natural selection.

• Laws of hydrodynamics constrain shapes possible for aquatic organisms that swim very fast.

• Animals shape, size, determine how animal exchanges materials with surroundings.

• Protist living in water – plasma membrane large to exchange materials through diffusion.

• Multicellular organisms – many smaller cells able to exchange materials through each one.

• Flat body – maximizes exposure to surroundings; prevents internal complexity.

• Most animals complex – cells small compared to volume.

• Allows animal to not be tied to land.

• Internal organs can regulate body.

Regulating Internal Environment

• Internal environment of vertebrates – interstitial fluid.

• Exchanges nutrients and wastes.

• Animals maintain homeostasis (internal balance) even when external environment changes.

http://titlev.fiu.edu/homeostasis/images/homeostasis_home.jpg

• Major internal changes are programmed to occur, such as during pregnancy.

• Homeostatic control system has 3 parts: receptor, control center, effector.

• 1Receptor – detects change in environment.

• 2Control center – processes change.

• 3Effector – directs response.

• Two types – 1Negative feedback control – change causes reaction in opposite direction.

• Fever – causes body to sweat to bring temperature down.

• 2Positive – change causes reaction in same direction.

• Labor – release in oxytocin increases uterine contractions.

• Regulated change important to survival.

• Can by cyclical (hormones), or reactive (fever)

• Internal regulation expensive in energy.

http://web.lemoyne.edu/~hevern/psy340/graphics/negative.feedback.jpg

Bioenergetics• Chemical energy needed for

growth, repair, regulation, reproduction.

• Food digested through hydrolysis, nutrients absorbed by cells.

• ATP use creates heat that is lost to environment.

• Energy left over – used for bioenergetics.

http://www.topicazos.com/fotos/digestion.jpg

• Bioenergetics - synthesis of storage material, production of reproductive structures, including gametes.

• Flow of energy through animal – sets limits on growth, behavior, reproduction, energy needs.

• Amount of energy used in given time – metabolic rate.

• Measured in calories.

• Metabolic rate can be determined by measuring amount of heat produced.

• 2 metabolic strategies used by animals.

http://www.nsf.gov/news/speeches/colwell/rc01aibs/img004.jpg

• 1Endothermic – birds, mammals - maintain body temperature at certain level with heat generated by metabolism.

• High-energy strategy – allows for intense activity.

• 2Ectothermic – reptiles, amphibians - do not produce enough metabolic heat to effect body temperature.

• Need less energy.

http://www.kidzone.ws/animals/polar_bear_2.jpg

• Amount of energy needed to maintain homeostasis inversely proportionate (per gram) to size.

• Each gram of a mouse consumes more energy than elephant.

• Smaller animal – higher metabolic rate to deliver oxygen, energy.

http://jan.ucc.nau.edu/~sll/images/Elephant-mouse.jpg

• Metabolic rate of nongrowing endotherm at rest, with empty stomach, experiencing no stress -basal metabolic rate (BMR)

• Metabolic rate of resting, fasting, nonstressed ectotherm - standard metabolic rate (SMR).

http://biology.unm.edu/jhbrown/Images/ScalingGraph.GIF

• Behavior above BMR or SMR consumes energy.

• Maximal BMR determines amount of energy expended.

• Ectotherms cannot do long, intense activity.

• BMR of human much higher than SMR of alligator.

• Factors influence BMR - age, sex, size, body and environmental temperatures, quality and quantity of food, activity level, oxygen availability, hormonal balance, time of day.

• How energy used varies among species.

• Endotherms need more energy; smaller animals need more energy.

• Human female spends large fraction of energy budget for BMR, relatively little for activity and temperature regulation.

• Male penguin spends larger fraction of energy expenditures for activity - must swim to catch food.