bio lec 3rd exam quilang lec notes

7/28/2019 Bio Lec 3rd Exam Quilang Lec Notes

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TISSUES

Anatomy study of the structure of an organismPhysiology study of the fxns an organism performs

Physical Laws and the Environment ConstrainAnimal Size and Shape- Body plan of an animal results from a pattern of

development programmed by the genome

Animal form and fxn are correlated at all levels of organization

Tissues groups of cells with a common structure andfxn- May be held together by a sticky extracellula r matrix

that coats the cells or weaves them together in afabric of fibers

1. EPITHELIAL- Tightly packed cells barrier - Covers outside of body and lines organs and cavities

w/in body- Free surface exposed to air/fluid- Fxns:, absorption, p rotection, e xcretion, s ecretion- Glandular epithelia secrete chemical solns

o Mucous membrane formed in the lining of lumen of digestive and respiratory tracts

Classifications of epithelia:a. No. of cell layers

o Simple epithelium 1 layer o Stratified epithelium multipleo ***Pseudostratified feeling stratified because

cells vary in lengthb. Shape of cells on exposed surface

o Cuboidalo Columnar o Squamous

- Stratified columnar epitheliumo Lines inner surface of urethra

- Simple columnar epitheliumo Lines the intestineso Secretes digestive juices and absorbs nutrients

- Pseudostratified ciliated columnar epitheliumo Forms mucus membrane respiratory tracto Cilia move a film of mucus along the surfaceo Trap dust and sweep them back up to the

trachea- Cuboidal epithelia

o Specialized for secretiono Kidney tubules and many glands, inc. thyroid

and salivary glandso Glandular epithelia in thyroid gland

Secretes hormone that regulates bodysrate of fuel consumption

- Simple squamous epitheliao Thin and leakyo Fxn in exchange of matl by diffusion

o Line blood vessels and air sacs, wherediffusion of nutrients and gases is critical

- Stratified squamus epitheliao Regenerate rapidly by cell division near

basement membraneo Surfaces subject to abrasion

Outer skin and linings of esophagus, anus,vagina

o Abrasion affects the oldest cells

**Basement membrane dense mat of extracellular matrix where the cells at the base of the epithelial layer are attached.

o CT secreted by epithelial and CT cells

2. CONNECTIVE TISSUE- Binds and supports tissues- Sparse population of cells scattered through an

extracellular matrix/ground substance- Matrix: web of fibers embedded in a uniform

foundationo Secreted by cells of connective tissue

- Made of fibers

Three kinds:a. Collagenous Fibers- Made of collagen most abundant protein in the

animal kingdom- Nonelastic- Dont tear easily when pulled lengthwise

b. Elastic Fibers

- Long threads made of protein elastin - Provide a rubbery quality that complements thenonelastic strength of collagenous fibers

- Restores skins original shape

c. Reticular fibers- Very thin and branched- Composed of collagen and continuous with

collagenous fibers, they form a tightly woven fabricthat joins connective tissue to adjacent tissues.

Major types of connective tissue in vertebrates:a. Loose connective tissue- Most widespread in the body- Binds epithelia to underlying tissues and fxns as

packaging matl, holding organs in place. - Includes CER- Two cells predominant in LCT:

o Fibroblasts secrete protein ingredients of the extracellular fibers

o Macrophages amoeboid cells that roam themaze of fibers, engulfing foreign particles andthe debris of dead cells by phagocytosis

b. Adipose tissue- Specialized form of LCT- Stores fat- Pads and insulates the body

- Stores fuel as fat molec- Swells fat is stored

c. Fibrous connective tissue- Dense (large no. of collagenous fibers)- Fibers: organized into parallel bundles

o Maximizes nonelastic strength- Found in tendons and ligaments

d. Cartilage- Abundance of collagenous fibers embedded in

chondroitin sulfate - Chondrocytes secrete chondroitin sulfate and

collagen

- Strong yet flexible support matl - Replaced by bone as embryo matures- Retained in some locations- Absorbs physical impact w/o breaking- Types:

o Hyaline cartilage clear, glassy appearanceTrachea, nose

o Elastic cartilageLobe of the ear, epiglottis

o Hydro cartilageknee joints

e. Bone- Make up skeleton- Mineralized connective tissue- Osteoblasts bone-forming cells that deposit a

matrix of collagen- Osteoclasts removes bone tissue by removing its

mineralized matrix- Ca + Mg + P = hydroxyapatite - Collagen + hard mineral = bone is harder than

cartilage but its not brittle. - Osteons/haversian systems have concentric

layers of mineralized matrixo Contain blood vessels and nerveso Canaliculi distributes nutrients

Interconnects lacunaeo Lacunae contains osteocytes

f. Blood- Plasma liquid in matrix

o H2O + salts + proteins- Suspended in plasma:

o Erythrocytes (RBC) O2o Leukocytes ( WBC) defense

Monocytes differentiate into

macrophagesArise from stem cells of bone marrow

Polymorphoneuclear/granulocytesHigh variable shape of nucleus.Circulating phagocytes in blood

Eosinophil secretes enzymes anddestroys allergens

Basophil blue secretes histamine Neutrophil most abundant in

humans

o Provide first line of defense iinfection

o Kill microbes throughphagocytosis

Lymphocytes develop anti-bodies B-cells secrete antibodies T-cells develop in thymus

o Platelets (cell fragments) - blood clotting

3. MUSCLE TISSUE- dont actively lengthen- originates from mesoderm- composed of long cells called muscle fibers that are

capable of contracting when stimulated by nerve

signals - Myofibrils contracting units arranged in parallelwithin the cytoplasm of MF

o Myofilaments: Actin thin

Actin molecule Troponin located at intervals a

actin o Globular subunits attached to

tropomyosin Tropmyosin - lie near grooves

between actin strands Myosin thick

2 polypeptide chains wound insupercoil head

o A-band broad region that corresponds to thlength of the thick filaments

o I-band region where there are only thinfilaments

o Z-line hold together the actin filamentsBorders of the sarcomere

o H-zone center of the A-band that containsonly thick filaments

Disappears when sarcomere contractso Sarcomere from one z-line to another

Fxnl unit of the myofibril - Most abundant in animals - Fascicule more complex - Sarcoplasmic reticulum stores calcium ions- Muscle contraction: accts for much of the E-

consuming cellular work in an active animal

Three types of muscle tissue:a. Skeletal muscle- Attached to the bones by tendons- Syncitium has several nuclei- For voluntary movets - Arrangement of sarcomere (contractile units) giv

cells a striated appearance.

b. Cardiac muscle- Single nucleus- For pumping blood- Striated but involuntary


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- Muscle fibers branch and interconnect viaintercalated disks

o Rely signals from cell to cell and helpsynchronize heartbeat

c. Smooth muscle- Lacks striations- Found in walls of visceral organs

o Blood vessel walls and walls of digestive tract- Spindle-shaped cells- Contract more slowly than skeletal but can remain

contracted longer - Controlled by diff kinds of nerves- Involuntary

- For movet of substances in l umens of body

4. NERVOUS TISSUE- Senses stimuli and transmits signals in the form of

nerve impulses- Neuron consists of a cell body and two or more

extensions or processeso Dendrites neuron tip rest of neurono Axons toward another neuron or effector o Cell bodyo Nucleuso Axon hillocko Myelin sheatho Synaptic terminalo Terminal branches

- Neuron can be:o Multipolar - several dendriteso Bipolar 1 dendrite and 1 axon

- Neuroglia supporting cell; insulates neuronmembranes

o Help in the nourishment of neuronsa. Microglia can be mobile

Fxn: protection phagocytosisb. Astrocyte lies bet nerve cells and

capillaryFxn: nourishment of neurons

c. Oligodendrocyte secretes cells for myelin sheath

Muscle fibers muscle cellNerve fiber neuronFibers in connective tissues proteins

LEVELS OF ORGANIZATION INORGANISMAL COMPLEXITY

1. Protoplasmic Organization in OrganismalComplexity

- Found in unicellular organismso Life fxns confined within the boundaries of a

single cell- Protoplasm differentiated into organelles

2. Cellular - Aggregation of cells functionally differentiated- Division of labor is evident- Most cells for nourishment- Some cells for reproduction

3. Cell-tissue- Aggregation of similar tissues into definite patterns of

layers thus becoming a tissueEx. Hydra

4. Tissue-organ- Aggregation of tissues into organs

- Eyespots, reproductiv e organs5. Organ System- Organs work together to perform some fxns- Systems are associated with basic body fxns

Ex. Nemerteam worm, ribbon worm (excretoryseparate from digestive)

ORGAN SYSTEMS- Carry out major body fxns- There must be coordination between systems for

animal to survive

Symmetry- Balanced proportion- Corresponden ce in size and shape of parts on

opposite sides of the median plane- Spherical any plane passing through the center

divides a body into equivalent, or mirrored, halveso Unicellular forms and rare in animalso Best suited for rolling and floating

- Radial forms that can be divided into similar halvesby more than two planes passing through thelongitudinal axis

o Tubular, vase or bowl shapeso Biradial only two planes passing through the

longitudinal axis produce mirrored halves.Ex. Comb jellies

o Usually sessile, freely floating, or weaklyswimming

- Bilateral divided along a sagittal plane into rightand left halves.

o Strongly associated with cephalization(differentiation of the head)

o Directional (forward movet) o Terms:

Anterior head Posterior tail Dorsal back Ventral belly Medial midline Lateral sides Distal farther from the middle of the

body Proximal nearer from the middle of the

body

Frontal plane/coronal plane dorsal/ventral

Sagittal plane right/left Transverse/xs anterior/posterior

- Segmentation metamerismo Metamere/somite segmento Serial repetition of similar body segments along

longitudinal axis of body

INTEGUMENTARY SYSTEM

Fxns:- Protection from mechanical and chemical injury and

invasion of microorganisms- Regulation of body temperature- Excretion of waste materials- Conversion of sunlight to vit. D- Reception of environmental stimuli such as pain,

temperature, pressure- Locomotion- Movet of nutrients and gases - Behavioral interaxn between individuals- Colorful display to attract mates

I. INVERTEBRATE INTEGUMENT

1. Plasma membrane- Unicellular protozoa- Gas exchange and waste removal by simple diffusion- Uptake of dissolved nutrients

- Pellicle o Thick protein coat found in protozoao Further environmental protectiono Semi-rigid structure transmits force of cilia of

flagella to entire body as the animal moves

2. Epidermis- Most multi-cellu lar invertebrat es- Single layer of columnar epithelial cells- Some invertebrat es have cuticle over their epidermis- Delicate and soft in mollusks and contain mucous

glands, some of which secrete CaCO2 of the shell

Mantle- Pair of folds formed by the dorsal body wall - Outer surface secretes shell - Molluscs: more complex integument consisting of

cuticle, simple epithelial, layer of connective tissue,

layer of reflecting cells (iridiocytes), and thicker layer of CT - Arthropods have the most complex of invertebrate

integuments o For protection and skeletal support

Procuticle inner Composed of protein and chitin

Epicuticle outer Nonchitous complex of protein andlipids

Seta Tegumental gland Tanning

The Arthropod cuticle may be hardened by:a. Calcification deposition of calcium carbonate

the outer layers of procuticle For crustaceans

b. Sclerotization protein molecules bond togethwith stabilizing cross-linkages within and betweenadjacent lamellae of the procuticle o Form of highly resistant and insoluble protein

s clerotino For insects

Molting of Arthropods- Epidermal cells are divided by mitosis- Epidermis secretes enzyme to digest procuticle- Absorption of digested materials- New epicuticle and procuticle formed beneath the old- New cuticle is thicker and calcified on sclerotized

II. VERTEBRATE INTEGUMENT

Skin and Derivatives:- Chromatophores pigment cells- 2 layers:

o Dermiso Epidermis

- Other structureso Arrector pili muscle found at the end of t

root hair for goosebumps

o hair o hair follicleo sebaceous glando nerve endingso hypodermis subcutaneous layer o sweat glands

Epidermis- stratified squamous epithelium- no blood vessels- cells of basal part undergo frog mitosis- as outer layer of cells are displaced upward by new

generations of cells beneath, keratinizationplace

o Keratin fibrous protein that accumulates inthe interior

- Cornified cells highly resistant to abrasions, H2diffusion, comprise outermost stratum corneum

o Result of keratinization (ex. Calluses)

Epidermal der ivat ives - Feathers, Nails, Hair, Scales of snake, Pelage, Hoof,

Plumage

Dermis- Dense connective tissue layer


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- With blood vessels, collagenous fibers, nerves,pigment cells, fat cells, and fibroblasts

- Support ,cushion and nourish epidermis- Macrophages and lymphocytes provide the first line

of defense

Dermal der ivat ives - Scales of fish, antlers, horn, caracase of turtle,

armadelum- Antlers of the deer shed velvet during the breeding

system o Velvet covering of highly vascular soft skin

Similarity of structure of integumentary derivatives

- Claw, horn, beak- All are built of similar combinations of epidermal(keratinized) and dermal components

Hairs- Epidermal growth that fxn in protection- Shaft, root, follicle- Sebaceous glands, arrector pili muscle, and hair root

plexus (touch)

Nails- Plates of highly packed, keratinized cells- Protection, scratching, and manipulation- Formed by cells in the nail bed called the matrix (in

area of lunula )o White because of the concentration of cells

- 1 mm/wk- Eponychium cuticle

Skin glands- Sebaceous (oil) glands- Usually connected to the hair follicles- Fats, cholesterol, proteins, salts, and cell debris- Moistens hair and skin and waterproofs skin- Blackheads are oxidized sebum

Sweat (sudoriferous glands)1. Eccrine sweat glands

o H2O, salt, wasteso Hairless regions, scattered over bodyo Fxn: to cool the body

2. Apocrine sweat glandso Larger o Associated with hair follicleso More viscous fatty acids and proteinso Restricted to axillae, breasts, prepuce,scrotum, external auditory canalso Odor occurs when broken down by bacteria

Propionic acid

Ceruminous glands- Modified sudoriferuos glands- Secrete cerumen (ear wax)

Mammary glands secrete milk

ANIMAL COLORATION- Vivid and dramatic when serving as important

recognition marks or warning coloration- Subdued or cryptic when used for camouflage- Aposematic coloration

o Poisonouso Warning coloration to advertize noxious

qualities

1. Structural color o Produced by the physical structure of the

surface tissue; tissue reflects certain lightwavelengths and eliminates others

o Phase interference effects of the microscopic

structure of featherso Different response depending on the directionor directionality illuminating

o Ex. Butterflies and some fishes

2. Color due to pigmentso Biochromes (pigments)o Reflect light rayso Chromatophores/pigment cells

Melanophores/melanocytesMelanin black

XantophoresCaroteniod red/yellow

IridiophoresCrystals of purine silvery/metallic

SKELETAL SYSTEM

Fxns:- Provide rigidity to the body- Surfaces for muscle attachment- Protection for vulnerable body organs

1. Hydrostatic SkeletonFxns:o Supports body formo Provides resistance for the contraction of

muscles to act againstSource:o Some organisms use their fluid-filled

gastrovascular cavityo Others use their fluid-filled coelom

- Main type of skeleton in most cnidarians & flatworms.

Earthworms:- Setae needlelike chitinous structure of integument- Septa wall between two coelomic cavities- Longitudinal muscle- Circular muscle- The alternate contraction of the CM and LM allow the

earthworm to move- They use muscles to change the shape of fluid filled

compartment

Muscu l a r Hydr os t a t s - Like hydrostatic skeletons, these work because they

are comprised of incompressible tissues that remainat constant volume

- Muscles arranged in complex patterns- No body fluid, only muscles- Ex. Tentacles , elephants trunk

2. Rigid skeletonso Consists of rigid elementso Usually jointedo Muscle attachmento Two principal types

Exoskeleton

Endoskeleton A. Exoskeleton external skeleton- Molluscs composed of calcium carbonate- Arthropods composed of chitin, a polysaccharide

similar to cellulose- Protection and locomotion

B. Endoskeleton internal- Echinoderm and vertebrates- Mineralized bone and cartilage- Support, protection, and reservoir of calcium and

phosphorus- Grows as the animal grows

o Does not limit space for internal organso Supports greater weight

Notochord

- Semi-rigid supportive axial rod of protochorda tes andall vertebrate larvae and embryos- Composed of large vacuolated cells surrounded by

elastic and fibrous sheaths- Stiffening device; preserves body shape during

locomotion- Exept in jawless vertebrates, surrounded or replaced

by the backbone during embryonic development

Cartilage- Major skeletal element of some vertebrat es- Soft pliable tissue that resists compression- Jawless vertebrates and elasmobranchs have purely

cartilaginous skeletons- No blood vessels

Bone- Living tissue having significant deposits of calcium

salts in the extracellular matrix- Highly vascular - Accdng to origin:

o Endochondrial or replacement boneOriginally found in cartilageEndochondral ossification

Replacement of cartilage by boneEmbryonic cartilage eroded osteoblasts invade honeycombed

areas deposit of Ca salts aroustrandlike remnants of the cartilatg

o Intramembranous boneDevelop directly from sheets of embryoncells

Dermal bone type of intramem. bonCranial, facial, clavicle

- Accdng to density: o Cancellous or spongy bone

Have irregular spacesCan still provide strength

o Compact bone - dense - Medullary Cavity filled with yellow bone marr

(fat storage)

- Spongy filled with red bone marrowBONE GROWTH AND RENEWAL- Cartilage structure in early development act as

models for future bones- Calcium salts deposited in the matrix by cartilage

cells and later by osteoblastso Endochondral ossification

Osteoclasts- Break down bone- Remove worn cells- Deposit Ca in the blood- Work with osteoblasts to heal broken bones

Hormones involved:- Parathyroid hormone stimulate bone resorpti

o Osteoclastso

From parathyroid gland- Calcitonin inhibits bone resorptiono Osteoblastso From thyroid gland

- 1.25 dihydroxyvitamin D 3 maintains Ca levelthe blood

o Vitamin D3

Plan of the vertebrate skeleton- 2 main divisions:

o Axial skeletonSkull, vertebral column, septum, ribs

o Appendicular skeletonLimbs, fins, wings, pectoral and pelvicgirdles

Human Skeletal System- Fxns:

o Supports and protects the bodyo Permits movemento Provides resistive foundation for muscles to ac

against- Bones store Ca and P ions- Certain bones produce RBC (ex. Sternum)

AXIAL SKELETONVertebral Column- Supports the head and trunk


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- Protects the spinal cord and roots of spinal nerves

Segments (from superior to interior)- Cervical neck- Thoracic chest- Lumbar small of back- Sacral sacrum/pelvic- Coccyx tailbone- Invertebral disks of fibrocartilage act as padding

- 33 in a young child- 5 vertebrate fuse to become the sacrum- 4 fuse to become the coccyx- 7 cervical vertebrates- 12 thoracic vertebrate- 5 lumbar vertebrate

Rib Cage- Protects the heart and lungs and assists breathing- Support by thoracic vertebrae- 12 pairs of ribs

o True ribsConnect directly to sternum7 pairs

o False ribsDo not connect directly to sternum5 pairs

APPENDICULAR SKELETON- Consists of:

o The bones within the pectoral and pelvicgirdles

o The attached limbs- Pectoral girdle bones of the shoulder o Anterior o Supports the arms and hands

- Pelvic girdle bones of the pelviso Posterior o Supports the legs and feet

Classification of Joints- Fibrous joints

o Immovableo Between cranial bones

- Cartilaginous jointso Slightly movableo Between vertebrae

- Synovial jointso Freely movableo Bones separated by a cavity

- Ligaments bind bones together at a joint

MOVEMENT

- Contractil e proteins change their form to relax or contract

o Actomyosin system

3 primary types:- Amoeboid- Ciliary and flagellar - Muscular

Ameboid movement- Amebas and other unicellular forms- WBC- Embryonic mesenchyme cells- Other mobile cells

Ameba:- Movement depends on actin and other regulatory

proteins - Ectoplasm located in peripheryo More rigid; gel-like

- Endoplasm found in central areas of cytoplasmo Contains nucleuso More fluid

- Pseudopod false foot- Hyaline cap- Endoplasmic stream

AMEBOID MOVEMENTConsensus model to explain extension andwithdrawal of pseudopodia and ameboid crawling:- Ectoplasm and endoplasm- Hyaline cap appears

o Part of ectoplasmo Transparent and hardened

- Endoplasm flows toward hyaline cap- Actin subunits attached to regulatory ABPs

o ABPs prevent actin from polymerizing intoactin microfilamentso Regulatory protein attached to actin

- Endoplasm fountains out to periphery- Actin subunits released and polymerized

o Bec. Of interaxn with phospholipids- Microfilaments cross linked- Ca2+ activate actin-secreting protein- Myosin associate with and pull on microfilaments

o Forces endoplasm to flow towards hyaline cap

CILIARY AND FLAGELLAR MOVEMENTCilia- Minute, hairlike, motile processes- Occur in large numbers- Ciliate protistans- Found in all major groups of animals- Move organisms through aquatic movement- Propel fluids and materials across surfaces- Nasa windpipes natin

Flagella- Whiplike longer - Present singly or in small nos- Occur in unicellular eukaryotes- Animal spermatozoa- Sponges

o Choanocyte with flagellum

To produce water currents

- Both cilia and flagella have the same ultrastructureo A core of microtubules sheathed by the plasma

membraneo 9 + 2 pattern

9 doubletso Flexible wheels of proteins connect outer

doublets to each other and to the coreMicrotubule associated proteins (MAPs)

o Outer doublets are connected by motor proteins

o Anchored in the cell by a basalbody/kinetosome

o Axoneme 9 + 2 tube of microtubules in aflagellum/cilium

o Dynein arm connect doubletsOperate to produce a sliding force betweenmicrotubules

o Radial spoke made of proteinsConnect outer doublets

- The bending of cilia and flagella is driven by the armsof a motor protein, dynein

o Addition to dynein of a phosphate group from ATP and its removal causes conformationchanges in the protein

o Dynein arms alternately grab, move andrelease outer microtubules

o Protein cross linked limit is sliding and force isexpressed as bending

Mechanism of ciliary movement:- Dynein arms link to adjacent microtubules swivel

and release in repeated cycles MT on concaveside to slide outward past MT on convex side curvature of cilium increases recovery stroke: MTon opposite side slide outward

Difference bet. C & F - beating patterns:- A flagellum has an undulatory movement

o Force is generated parallel to the flagellumsaxis

- Cilia move more like oars with alternating power andrecovery strokes

o Generate force perpendicular to cilias axis

INVERTEBRATE MUSCLEBivalve molluscan muscles

- 2 kinds of fiberso Fast muscle fibers

Striated, can contract rapidlyEnables bivalves to snap shut its valveswhen disturbedEx. Scallops

o Smooth muscleCapable of slow, long-lasting contractions

Adductor muscle yung naiiwan sashell ng clam

o Kaya ayaw mag-open

Insect flight muscles (fibrillar muscle)- Wings of small flies operate at 1000 beats/sec- Limited extensibly, shorten only slightly- Direct muscles connected to wings

o Not present in flies and midgets, but present inlocusts and dragonflies

o Contraction of this causes the downstrokemovement

- Indirect muscles connected to thoraxo Cause wing movement by altering the shape o

the thorax- Prothorax-

MesothoraxStructure of Striated Model*** he talked about the parts of the muscles here.Please refer to the muscle tissue shit on p. 1 ***

Sliding Filament Model- Actin filaments at both ends of sarcomere

o One end of each filament is attached to a Z-plate at one end of the sarcomere

o Other suspended in sarcoplasm - Myosin filaments in between Z-plates

o Myosin filaments contain cross-bridges whichpull the actin filament inward

o Causes Z plates to move toward each oneo Shortens sarcomere o Sarcomeres stacked together in series cause

myofibers to shorten - Working muscles require ATP o Myosin breaks down ATP o Sustained exercise

Requires cellular respiration Regenerates ATP

Muscle innervations- Neuromuscular junction

o Synaptic contact between a nerve fiber and amuscle fiber

o Nerve impulses bring about the release of aneurotransmitter that crosses the synaptic cleft

o Signals the muscle fiber to contract

Axon:- Axon terminal- Axon branch

- Synaptic vessels stores acetylcholine- Synaptic cleft thinly separates a nerve fiber andmuscle fiber

- Acetylcholine released when a nerve impulse oaction potential reaches a synapse

o Diffuses across the synaptic cleft and acts onthe scarcolemma to generate an electricaldepolarization.

- Synapse special chemical bridge that couplestogether the electrical act. Of nerve & muscle fibers


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How does a muscle contract?1. Action potential sarcolemma sarcoplasmic

reticulum (thru t-tubules)2. Ca ions released bind to troponin torponin

and tropomyosin move away from the active site myosin x-bridges bind to exposed active sites

3. Myosin head swings toward the center of thesarcomere (ATP) ADP and phosphate group arereleased

4. Myosin heads bind to another ATP molecule myosin head is freed from the active site

5. Myosin head splits ATP energy released isretained

Human muscular system- Skeletal muscles

o Attached to the skeleton by cable-like fibrousCT called tendons

o Arranged in antagonistic (opposite) pairsCan only contract; cannot pushWhen 1 muscle contracts, it stretches itsantagonistic partner

- A muscle at rest exhibits tone (minimal contraction)- A muscle in tetany is a maximum sustained

contraction

Muscle performance- Slow oxidative fibers (red muscles)

o For slow, sustained contractions withoutfatigue

o Contain extensive blood supplyo

High density of mitochondriao Abundant stored myoglobino Important in maintaining posture in terrestrial

vertebrate- 2 kinds of fast fibers :

o Fast glycolytic fiber (white)Lacks efficient blood supplyPale in color Fxn anaerobicallyFatigue rapilyEx. Weightlifters, white meat

o Fast oxicdative fiber Extensive blood supplyHigh density of mitochondria andmyoglobinFxn aerobaticallyFor rapid, sustained activitiesEx. Runners

Energy for contraction- ATP , immediate source of E- Glucose broken down during aerobic metabolism- Glycogen stores can supply glucose- Muscles have creatine phosphates , an E reserve- Slow and fast oxidative fibers rely heavily on glucose

and O2- Fast glycolitic fibers rely on anaerobic glycolisis- Muscles incur O2 debt during anaerobic glycolysis

Creatine P + ADP ATP + creatine

Importance of tendons in E storage- KE is stored from step to step as extra elastin strain

energy in tendons- Bounces along on its tendons- Uses far less E than would be required if every step

relied on alternate muscle contraction and relaxation

DIGESTION

Dietary categories:

1. Herbivores2. Carnivores3. Omnivores4. Saprophagous decaying organic matter

Ex. Woodlice, deer fly, hermit beetle, red ant

Feeding Adaptations- Suspension feeder sits through food particles in

the water o Coprophagy consume food pellets

Rabbits, hareso Bivalve molluscs use their gills as feeding

devices as well as for respiration. Water currents created by cilia on the gills carry foodparticles into the incurrent siphon and betweenslits in the gills where they are entangled in amucous sheet covering the gill surface. Ciliatedfood grooves then transport the particles to themouth.

o Herring and other suspension-feeding fishesuse gill rakers that project forward from the gillarches into the pharyngeal cavity to strainplankton. Herring swim almost constantly,forcing water and suspended food into their mouth; food is strained by their gill rakers andwater passes through the gill openings

- Deposit feeder eats its way through dirt or sediments and extract partially decayed organicmaterial consumed along with the soil or sediments

o Ex. earthworm- Substrate feeder lives in or on its food source,

eating its way through the foodo Ex. Leaf miners

- Fluid feeder sucks nutrient rich fluids from a livinghost and is considered a parasite.

o Ex. Mosquito- Bulk feeder - eats relatively large pieces of food

o Ex. Python

- Cephalopod molluscs have beak-like jaws whichserve as tearing devices

- Chewing mouthparts adapted for seizing andcrushing food

- Mandibles are strong, toothed plates whose edgescan bite or tear

- Maxillae hold food and pass it toward the mouth- Birds lack teeth- Bills are often provided with serrated edges- Upper bill is hooked for seizing and tearing prey

- Four types of teeth found in mammals:o Incisors for biting, cutting, and strippingo Canines for seizing, piercing, and tearingo Premolars for grinding and crushingo Molars for grinding an crushing

- An elephants tu sk is a modified upper incisor - Used for defense, attack and rooting- A male wild boar has modified canines that are used

as weapons

Types of Digestive System1. Incomplete there is only one opening; no anus2. Complete there is a mouth opening and an anus

Four main stages of food processing1. Ingestion the act of eating2. Digestion breaking down food into molecules

small enough for the body to absorb3. Absorption small molecules are taken in by the

animals cells 4. Elimination undigested material passes out of

the digestive compartment

- Digestion is entirely intracellular in protozoa andsponges

- Radiates, tubellarian flatworms, and ribbon wormspractice both intracellular and extracellular digestion

-In extracellular digestion, certain cells lining thelumen of alimentary canals form digestive secretions,other cells fxn in absorption

- For arthropods and vertebrates digestion is almostentirely extracellular

Gut movement- Alternate constriction of rings of smooth muscle of

the intestine- Constantly divide and squeeze contents back and

forth- For mixing of food

- Waves of contraxn of circular muscle behind the gutand relaxation in front of bolus

- Sweeps food down the gut

1. Reception: mouth parts; salivary glands

- Amylase beings hydrolysis of plant and animalstarches

o Found only in certain herbivorous moluscs,some insects, and in primate animals

o Breaks into two-glucose fragments (maltose)- Tongue pushes moistened food toward the pharynx

nasal cavity closes reflexively by raising the softalate as food slides into pharynx , epiglottis tipsdown over the trachea, nearly closing it

espohagous: peristaltic contaxn of esophagealmuscles stomach

2. Conduction: Esophagous

3. Storage and Early Digestion: stomach(vertebrates); crop (insects, birds)

- Stomach provides initial digestion as well asstorage and mixing of food with digestive juices

- Cardiac sphincter opens reflexively when fooarrives at the stomach to allow food to enter.

o Closes to prevent regurgitation back into theesophagous

- Churning most vigorous at the intestinal end whefood is steadily released into the duodenum (1region of small intestine)

- Gastric juice secreted by deep tubular glands inthe stomach wall

o 3 types of cells that line these glands: Goblet cells secrete mucus Chief cells secrete pepsinogen

Pepsinogen precursor of pa protease (protein-splittingenzyme) that is produced frompepsinogen only in an acid mediu

Parietal/oxyntic cells secrete HCl- Rennin milk-curdling enzyme found in the

stomachs of ruminant animalso Slows movet of milk through stomach by

clotting and precipitating milk proteins

4. Grinding : gizzard (birds), proventiculus (insects)- Gizzard assisted by stones and grit swallowedalong w/ food

5. Terminal digestion and absorption: smalintestine (vertebrates), midgut (insects)

- Increase absorptive surface of gut increase- Villi minute fingerlink projections

o give the inner surface of fresh intestinal tissuethe appearance of velvelt

o birds and mammals- Microvilli lines each cell in the intestinal cavity- Pyloric sphincter - regulates flow of food into th

intestine (duodenum) and prevents regurgitation intothe stomach

o Relaxes at intervals to allow entry of acidicstomach contents

- Two secretions in this region:o Pancreatic juiceo Bile

Collects in the gallbladder Releases bile when stimulated bythe presence of fatty food in theduodenum

Water, bile salts, pigments, no enzymesBile salts essential for digestion of fat

Reduce surface tension of fatglobules intestine breaks fattiny droplets


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Bile pigments produce the yellow-greencolor

Also give feces its characteristiccolor

Liver produces bileo Both have high bicarbonate content, which

effectively neutralizes gastric acidRaises pH of liquefied food mass ( chyme )

6. Water absorption, concentration of solids: largeintestine (vertebrates); hindgut (insects)

- ** malphigian tubules excretory organs** cecum

Region Secretion pH CompositionSalivaryglands

Saliva 6.5 AmylaseBicarbonate

Stomach Gastric juice 1.5 PepsinogenHClRennin in ruminantmammals

Liver andgallbladder

Bile 7-8 Bile salts and pigmentsCholesterol

Pancreas Pancreatic juice

7-8 Trypsin, chymotrypsin,carboxypeptidase,lipase, amylase,nucleases, bicarbonate

Smallintestine

Membraneenzymes

7-8 AminopeptidaseMaltaseLactaseSucrose

Alkaline phosphatase

- Trypsin, chymotrypsin , and carboxypeptidase aresecreted in inactive form by the pancreaso The intestinal enzyme, enteropeptidase

converts inactive trypsinogen into active trypsino Active trypsin then activates the other two

- Disaccharidases split 12-carbon sugar moleculesinto 6-carbon units

o Maltase, sucrose, lactase- Chylomicrons fatty acids + protein + cholesterol- lacteal

- The colon recovers water that has entered thealimentary canal as the solvent to various digestive

juiceso 7 L of fluid are secreted into the lumen of the

digestive tract each dayo 90% of water is reabsorbed mostly in the small

intestine, the rest in the colono The feces become more solid as they are

moved along the colon by peristalsiso It takes 12 to 24 hours for material to travel the

length of the colono Diarrhea results if insufficient water is

absorbed and constipation if too much water isabsorbed

- The large intestine harbors a rich flora of mostlyharmless bacteria

o Escherichia coli - one of the most commoninhabitants of the human colon

o Many coon bacteria generate gases, includingmethane and hydrogen sulfide

o Some bacteria produce vitamins, includingbiotin, folic acid, vitamin K, and several Bvitamins, which supplement our dietary intakeof vitamins

** helicobacter pylori secretes toxins causinginflammation of the stomachs lining

- The terminal portion of the colon is called the rectum,where feces are stored until they can be eliminated

o Between the rectum and the anus are twosphincters; one involuntary and one voluntary

o Once or more each day, strong contractions of the colon create an urge to defecate

Regulation of digestion- The length of the vertebrate digestive system is also

correlated with diet - The most elaborate adaptations for a herbivorous

diet have evolved in the ruminants, which includedeer, cattle, and sheep

- The human body regulates the use and storage of glucose, a major cellular fuel

Nutritional Requirements- A nutritionally adequate diet satisfies three needs:

o Fuel (chemical energy) for all the cellular workof the body

o Organic raw materials animals use in

biosynthesis (carbon skeletons to make manyof their own molecules) o Essential nutrients

- If the diet of a person, or other animal is chronicallydeficient in calories, undernourishment results

- An animal whose diet is missing one or moreessential nutrients is said to be malnourished

- Marasmus , general undernourishment froma dietlow in both calories and protein

- Kwashiorkor , a protein malnourishment from a dietadequate in calories but deficient in protein

- Overnourishment or obesity results from excessivefood intake

- In mammals, a hormone called leptin, produced byadipose cells, is a key player in a complex feedbackmechanism regulating fat and storage use.

o High leptin level cues the brain to depress

appetite and to inc energy-consumingmuscular activity and body-heat production o Loss of body fat decreases leptin levels in the

blood, signaling the brain to increase appetiteand weight gain.

Appetite-regulating hormones- Ghrelin (stomach wall)

o Triggers feelings of hunger as mealtimesapproach

- Leptin (adipose tissue) o Suppresses appetite

- PYY (small intestine) o After meals o Appetite suppressant; counters ghrelin

- Insulin (pancreas) o a rise in blood sugar level after a meal o suppresses appetite by acting on the brain

- animals require 20 amino acids to make proteins - Essential amino acids must be obtained from food

in prefabricated form o Adult humans:

Phenylalanine Lysine Isoleucine Leucine Valine Methionine Tryptophan Threonine

o Histidine and arginine essential for normalgrowth of children

- Protein deficiency from a vegetarian diet can beavoided by eating a combination of plant foods thatcomplement each other to supply all essential aminoacids

- Vitamins are organic molecules required in the dietin small quantities

- 13 vitamins essential to humans have been identified -

Water-soluble vitamins generally fxn as co-enzymes - Minerals are simple inorganic nutrients, usually reqd

in small amts o Humans and other vertebrates require large

quantities of Ca and P for the construction andmaintenance of bone

o Iron component of the cytochromes and of hemoglobin

o Na, K, Cl major influence on the osmoticbalance bet cells and the interstitial fluids, butexcess consumption of salt (NaCl) is harmful

GAS EXCHANGE

- Cellular respiration oxidative processes withincells

- External respiration exchange of O2 and CO2between the organism and its env

Gas Exchange Surfaces- For diffusion to be effective, gas-exchange regions

must be:o Moisto Thino Relatively large

- Effectiveness of diffusion is enhanced byvascularization

Respiratory Organs- Cutaneous respiration (direct diffusion)- Tracheal systems (branching system of tubes)- Gills or branchia (external/internal)

How a fish ventilates its gills

Conutercurrent flow/exchange

Respiratory Organs- Lungs (invaginations)

o Positive pressure breathingFrog

o Negative pressure breathingMammals

- The volume of air an animal inhales and exhales witheach breath is called tidal volume

o It averages about 500 mL in resting humans- The max tidal volume during forced breathing is the

vital capacity , wc is about 3.4 L and 4.8 L for college-age F and M, respectively

- Most animals transport most of the O2 bound tospecial proteins called respiratory pigments

o Hemocyanino Hemoglobin

- When the control center registers a slight drop in pH,it increases the depth and rate of breathing, and theexcess CO2 is eliminated in exhaled air

3 types of neurons:1. Motor/efferent2. Sensory/afferent3. Interneuron

- O2 diffuses into pulmonary capillaries- Most O2 combines w/ hemoglobin in RBC to form

oxyhemoglobin - Co2 diffuses out of pulmonary capillaries- Most CO2 is transported in the form of bicarbonate

ion- Some CO2 combines with hemoglobin to form

carbaminohemoglobin

- Cooperative O2 binding and release is evident in thedissociation curve for hemoglobin

- A drop in pH lowers the affinity of hemoglobin for O

an effect called the Bohr shift

bio lec 3rd exam quilang lec notes

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