Bio Lec 3rd Exam Lec Notesila

7/31/2019 Bio Lec 3rd Exam Lec Notesila

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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 oforganization

Tissues groups of cells with a common structure and

fxn- May be held together by a sticky extracellular 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, protection, excretion, secretion- 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 layerso Simple epithelium 1 layer

o Stratified epithelium multiple

o ***Pseudostratified feeling stratified because

cells vary in lengthb. Shape of cells on exposed surface

o Cuboidal

o Columnaro Squamous

- Stratified columnar epitheliumo Lines inner surface of urethra

- Simple columnar epitheliumo Lines the intestines

o Secretes digestive juices and absorbs nutrients

- Pseudostratified ciliated columnar epithelium

o Forms mucus membrane respiratory tract

o Cilia move a film of mucus along the surfaceo Trap dust and sweep them back up to the

trachea- Cuboidal epithelia

o Specialized for secretion

o 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 leaky

o Fxn in exchange of matl by diffusion

o Line blood vessels and air sacs, where diffusion

of nutrients and gases is critical- Stratified squamus epithelia

o 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 layerare attached.

o CT secreted by epithelial and CT cells

2. CONNECTIVE TISSUE- Binds and supports tissues

- Sparse population of cells scattered through anextracellular matrix/ground substance

- Matrix: web of fibers embedded in a uniformfoundationo 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 the

nonelastic strength of collagenous fibers- Restores skins original shape

c. Reticular fibers- Very thin and branched

- Composed of collagen and continuous withcollagenous 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 the

maze 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. Carti lage

- Abundance of collagenous fibers embedded inchondroitin sulfate

- Chondrocytes secrete chondroitin sulfate andcollagen

- 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 appearance

Trachea, noseo Elastic cartilage

Lobe of the ear, epiglottiso Hydro cartilage

knee joints

e. Bone- Make up skeleton- Mineralized connective tissue

- Osteoblasts bone-forming cells that deposit amatrix of collagen

- Osteoclasts removes bone tissue by removing itsmineralized matrix

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

cartilage but its not brittle.

- Osteons/haversian systems have concentriclayers of mineralized matrixo Contain blood vessels and nerveso Canaliculi distributes nutrients

Interconnects lacunae

o Lacunae contains osteocytes

f. Blood

- Plasma liquid in matrixo H2O + salts + proteins

- Suspended in plasma:

o Erythrocytes (RBC) O2

o Leukocytes (WBC) defense

Monocytes differentiate intomacrophages

Arise from stem cells of bone

Polymorphoneuclear/granulocyte

High variable shape of nucleuCirculating phagocytes in bloo

Eosinophil secretes enzym

destroys allergens

Basophil blue secretes his

Neutrophil most abundant

humanso Provide first line of defen

infectiono Kill microbes through

phagocytosis

Lymphocytes develop anti-bodie

B-cells secrete antibodies

T-cells develop in thymus

o Platelets (cell fragments) - blood clottin

3. MUSCLE TISSUE- dont actively lengthen

- originates from mesoderm- composed of long cells called muscle fibers th

capable of contracting when stimulated by ne

signals- Myofibrils contracting units arranged in par

within the cytoplasm of MFo Myofilaments:

Actin thin

Actin molecule

Troponin located at intervaactino Globular subunits attache

tropomyosin

Tropmyosin - lie near groov

between actin strands

Myosin thick

2 polypeptide chains wound i

supercoil

heado A-band broad region that correspond

length of the thick filaments

o I-band region where there are only th

filaments

o Z-line hold together the actin filament

Borders of the sarcomere


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o H-zone center of the A-band that contains

only thick filaments

Disappears when sarcomere contracts

o 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) givescells a striated appearance.

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

- Muscle fibers branch and interconnect viaintercalated diskso Rely signals from cell to cell and help

synchronize heartbeat

c. Smooth muscle

- Lacks striations- Found in walls of visceral organso 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 lumens 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 moreextensions or processes

o Dendrites neuron tip rest of neuron

o Axons toward another neuron or effector

o Cell body

o Nucleuso Axon hillock

o Myelin sheath

o Synaptic terminal

o Terminal branches

- Neuron can be:

o Multipolar- several dendrites

o Bipolar 1 dendrite and 1 axon

- Neuroglia supporting cell; insulates neuronmembraneso Help in the nourishment of neurons

a. Microglia can be mobile

Fxn: protection phagocytosis

b. Astrocyte lies bet nerve cells andcapillary

Fxn: nourishment of neurons

c. Oligodendrocyte secretes cells formyelin 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. Cel lu lar

- 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, reproductive organs

5. 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- Correspondence in size and shape of parts on

opposite sides of the median plane

- Spherical any plane passing through the centerdivides a body into equivalent, or mirrored, halveso Unicellular forms and rare in animals

o Best suited for rolling and floating

- Radial forms that can be divided into similar halvesby more than two planes passing through thelongitudinal axiso Tubular, vase or bowl shapes

o Biradial only two planes passing through the

longitudinal axis produce mirrored halves. Ex. Comb jellies

o Usually sessile, freely floating, or weakly

swimming

- Bilateral divided along a sagittal plane into right andleft 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 thebody

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 patemperature, 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 - Uptake of dissolved nutrients- Pellicle

o Thick protein coat found in protozoao Further environmental protection

o Semi-rigid structure transmits force o

flagella to entire body as the animal mo

2. Epidermis

- Most multi-cellular invertebrates- Single layer of columnar epithelial cells- Some invertebrates have cuticle over their ep- Delicate and soft in mollusks and contain muc

glands, some of which secrete CaCO2 of the s

Mantle- Pair of folds formed by the dorsal body wall- Outer surface secretes shell

- Molluscs: more complex integument consistincuticle, simple epithelial, layer of connective ti

layer of reflecting cells (iridiocytes), and thickeof CT

- Arthropods have the most complex of invertebintegumentso For protection and skeletal support

Procuticle inner

Composed of protein and chit

Epicuticle outer

Nonchitous complex of proteilipids

Seta

Tegumental gland

Tanning

The Arthropod cuticle may be hardened by:

a. Calcification deposition of calcium carbothe outer layers of procuticle

For crustaceans

b. Sclerotization protein molecules bond towith stabilizing cross-linkages within and beadjacent lamellae of the procuticle

o Form of highly resistant and insoluble p

sclerotino For insects


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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 structures

o Arrector pili muscle found at the end of the

root hair

for goosebumpso hairo hair follicle

o sebaceous gland

o nerve endings

o 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, keratinization takesplace

o Keratin fibrous protein that accumulates in

the interior

- Cornified cells highly resistant to abrasions, H2Odiffusion, comprise outermost stratum corneumo Result of keratinization (ex. Calluses)

Epidermal derivatives

- Feathers, Nails, Hair, Scales of snake, Pelage, Hoof,Plumage

Dermis- Dense connective tissue layer- With blood vessels, collagenous fibers, nerves,

pigment cells, fat cells, and fibroblasts- Support ,cushion and nourish epidermis

- Macrophages and lymphocytes provide the first line ofdefense

Dermal derivatives

- Scales of fish, antlers, horn, caracase of turtle,armadelum

- Antlers of the deer shed velvet during the breedingsystem

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 (inarea oflunula)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, wastes

o Hairless regions, scattered over bodyo

Fxn: to cool the body

2. Apocrine sweat glandso Largero Associated with hair follicles

o More viscous fatty acids and proteins

o 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 milkANIMAL COLORATION- Vivid and dramatic when serving as important

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

o Poisonous

o 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 direction or

directionality illuminatingo Ex. Butterflies and some fishes

2. Color due to pigments

o Biochromes (pigments)

o Reflect light rays

o Chromatophores/pigment cells

Melanophores/melanocytes

Melanin black

Xantophores

Caroteniod red/yellow

Iridiophores

Crystals 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

Muscular Hydrostats- 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 elements

o Usually jointed

o Muscle attachment

o Two principal types

Exoskeleton

Endoskeleton

A. Exoskeleton external skeleton

- Molluscs composed of calcium carbonate- Arthropods composed of chitin, a polysacch

similar to cellulose

- Protection and locomotion

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

phosphorus- Grows as the animal grows

o Does not limit space for internal organs

o Supports greater weight

Notochord

- Semi-rigid supportive axial rod of protochordaall vertebrate larvae and embryos

- Composed of large vacuolated cells surroundelastic and fibrous sheaths

-Stiffening device; preserves body shape durin

locomotion- Exept in jawless vertebrates, surrounded or re

by the backbone during embryonic developme

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

cartilaginous skeletons- No blood vessels

Bone- Living tissue having significant deposits of ca

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

o Endochondrial or replacement bone

Originally found in cartilage Endochondral ossification

Replacement of cartilage by b

Embryonic cartilage eroded

osteoblasts invade honeycom

areas deposit of Ca salts astrandlike remnants of the car

o Intramembranous bone


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Develop directly from sheets of embryoniccells

Dermal bone type of intramem. bone

Cranial, facial, clavicle- Accdng to density:

o Cancellous or spongy bone

Have irregular spaces

Can still provide strength

o Compact bone - dense

- Medullary Cavity filled with yellow bone marrow (fatstorage)

- Spongy filled with red bone marrow

BONE 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 resorptiono Osteoclasts

o From parathyroid gland- Calcitonin inhibits bone resorption

o Osteoblasts

o From thyroid gland

- 1.25 dihydroxyvitamin D3 maintains Ca level in thebloodo Vitamin D3

Plan of the vertebrate skeleton- 2 main divisions:

o Axial skeleton

Skull, vertebral column, septum, ribso Appendicular skeleton

Limbs, fins, wings, pectoral and pelvicgirdles

Human Skeletal System- Fxns:

o Supports and protects the bodyo Permits movement

o Provides resistive foundation for muscles to act

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

AXIAL SKELETON

Vertebral Column- Supports the head and trunk- 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 ribs

Connect directly to sternum 7 pairs

o False ribs

Do not connect directly to sternum

5 pairs

APPENDICULAR SKELETON- Consists of:

o The bones within the pectoral and pelvic girdles

o The attached limbs

- Pectoral girdle bones of the shouldero 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 Immovable

o Between cranial bones

- Cartilaginous joints

o Slightly movableo Between vertebrae

- Synovial jointso Freely movable

o Bones separated by a cavity

- Ligaments bind bones together at a joint

MOVEMENT

- Contractile proteins change their form to relax orcontract

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 periphery

o More rigid; gel-like

- Endoplasm found in central areas of cytoplasmo Contains nucleus

o 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 ectoplasm

o Transparent and hardened

- Endoplasm flows toward hyaline cap

- Actin subunits attached to regulatory ABPso ABPs prevent actin from polymerizing into

actin 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 ultrastruo A core of microtubules sheathed by the

membraneo 9 + 2 pattern

9 doubletso Flexible wheels of proteins connect ou

doublets to each other and to the core

Microtubule associated proteins (Mo Outer doublets are connected by motor

o Anchored in the cell by a basal

body/kinetosome

o Axoneme 9 + 2 tube of microtubule

flagellum/cilium

o Dynein arm connect doublets

Operate to produce a sliding force bmicrotubules

o Radial spoke made of proteins

Connect outer doublets

- The bending of cilia and flagella is driven by thof a motor protein, dyneino Addition to dynein of a phosphate grou

ATP and its removal causes conformatichanges in the protein

o Dynein arms alternately grab, move and

outer microtubuleso Protein cross linked limit is sliding and f

expressed as bending

Mechanism of ciliary movement:

- Dynein arms link to adjacent microtubules

and release in repeated cycles MT on conc

to slide outward past MT on convex side cu

of cilium increases recovery stroke: MT on

side slide outward

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

o Force is generated parallel to the flagel

axis- Cilia move more like oars with alternating pow

recovery strokeso Generate force perpendicular to cilias a


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INVERTEBRATE MUSCLEBivalve molluscan muscles- 2 kinds of fibers

o Fast muscle fibers

Striated, can contract rapidly

Enables bivalves to snap shut its valveswhen disturbed

Ex. Scallopso Smooth muscle

Capable 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 wingso Not present in flies and midgets, but present in

locusts and dragonflieso Contraction of this causes the downstroke

movement

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

the thorax- Prothorax- Mesothorax

Structure of Striated Model*** he talked about the parts of the muscles here. Pleaserefer 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 sarcomereo Other suspended in sarcoplasm

- Myosin filaments in between Z-plateso Myosin filaments contain cross-bridges which

pull the actin filament inward

o Causes Z plates to move toward each one

o Shortens sarcomereo 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 junctiono Synaptic contact between a nerve fiber and a

muscle fibero Nerve impulses bring about the release of a

neurotransmitter 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 oraction potential reaches a synapseo Diffuses across the synaptic cleft and acts on

the scarcolemma to generate an electricaldepolarization.

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

How does a muscle contract?

1. Action potential sarcolemma sarcoplasmicreticulum (thru t-tubules)

2. Ca ions released bind to troponin torponin andtropomyosin move away from the active sitemyosin 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 moleculemyosin 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 fibrous

CT called tendonso Arranged in antagonistic (opposite) pairs

Can only contract; cannot push

When 1 muscle contracts, it stretches itsantagonistic partner

- A muscle at rest exhibits tone (minimal contraction)

- A muscle in tetany is a maximum sustainedcontraction

Muscle performance

- Slow oxidative fibers (red muscles)o For slow, sustained contractions without fatigue

o Contain extensive blood supplyo High density of mitochondria

o Abundant stored myoglobin

o Important in maintaining posture in terrestrial

vertebrate

- 2 kinds offast fibers:o Fast glycolytic fiber (white)

Lacks efficient blood supply

Pale in color

Fxn anaerobically Fatigue rapily

Ex. Weightlifters, white meato Fast oxicdative fiber

Extensive blood supply

High density of mitochondria and myoglobin

Fxn aerobatically

For rapid, sustained activities

Ex. 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 incurO2 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 strainenergy 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. Omnivores

4. Saprophagous decaying organic matterEx. Woodlice, deer fly, hermit beetle, red ant

Feeding Adaptations

- Suspension feeder sits through food particles inthe water

o Coprophagy consume food pellets

Rabbits, hareso Bivalve molluscs use their gills as feeding

devices as well as for respiration. Watercurrents 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 fishes

use gill rakers that project forward from the gill

arches into the pharyngeal cavity to straplankton. Herring swim almost constantforcing water and suspended food into tmouth; food is strained by their gill rakewater passes through the gill openings

- Deposit feeder eats its way through dirt orsediments and extract partially decayed organmaterial consumed along with the soil or sedimo Ex. earthworm

- Substrate feeder lives in or on its food soueating its way through the foodo Ex. Leaf miners

- Fluid feeder sucks nutrient rich fluids from

host and is considered a parasite.o Ex. Mosquito

- Bulk feeder- eats relatively large pieces of foo Ex. Python

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

- Chewing mouthparts adapted for seizing and food

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

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

- Four types of teeth found in mammals:

o Incisors for biting, cutting, and strippio Canines for seizing, piercing, and tea

o Premolars for grinding and crushing

o Molars for grinding an crushing

- An elephants tusk is a modified upper incisor- Used for defense, attack and rooting- A male wild boar has modified canines that ar

as weapons

Types of Digestive System

1. Incomplete there is only one opening; no

2. Complete there is a mouth opening and a

Four main stages of food processing

1. Ingestion the act of eating

2.Digestion breaking down food into molecsmall enough for the body to absorb

3. Absorption small molecules are taken in animals cells

4. Elimination undigested material passes odigestive compartment

- Digestion is entirely intracellular in protozoa asponges


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

- In extracellular digestion, certain cells lining the lumenof alimentary canals form digestive secretions, othercells 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 animal

starcheso Found only in certain herbivorous moluscs,

some insects, and in primate animalso Breaks into two-glucose fragments (maltose)

- Tongue pushes moistened food toward the pharynxnasal cavity closes reflexively by raising the soft

alate as food slides into pharynx, epiglottis tips

down over the trachea, nearly closing it espohagous: peristaltic contaxn of esophageal

muscles 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 foodarrives at the stomach to allow food to enter.o Closes to prevent regurgitation back into the

esophagous

- Churning most vigorous at the intestinal end wherefood is steadily released into the duodenum (1st regionof small intestine)

- Gastric juice secreted by deep tubular glands in thestomach wall

o 3 types of cells that line these glands:

Goblet cells secrete mucus

Chief cells secrete pepsinogen

Pepsinogen precursor of pepsin,

a protease (protein-splitting enzyme)that is produced from pepsinogenonly in an acid medium

Parietal/oxyntic cells secrete HCl

- Rennin milk-curdling enzyme found in the stomachsof 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: smallintestine (vertebrates), midgut (insects)

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

o give the inner surface of fresh intestinal tissue

the appearance of velvelto birds and mammals

- Microvilli lines each cell in the intestinal cavity

- Pyloric sphincter - regulates flow of food into theintestine (duodenum) and prevents regurgitation intothe stomacho Relaxes at intervals to allow entry of acidic

stomach contents- Two secretions in this region:

o Pancreatic juice

o Bile

Collects in the gallbladder

Releases bile when stimulated by

the presence of fatty food in theduodenum

Water, bile salts, pigments, no enzymes

Bile salts essential for digestion of fats

Reduce surface tension of fat

globules intestine breaks fat intotiny droplets

Bile pigments produce the yellow-greencolor

Also give feces its characteristiccolor

Liver produces bileo Both have high bicarbonate content, which

effectively neutralizes gastric acid

Raises pH of liquefied food mass (chyme)

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

** malphigian tubules excretory organs** cecum

Region Secretion pH Composition

Salivaryglands

Saliva 6.5 AmylaseBicarbonate

Stomach Gastric juice 1.5 Pepsinogen

HClRennin in ruminantmammals

Liver andgallbladder

Bile 7-8 Bile salts and pigmentsCholesterol

Pancreas Pancreaticjuice

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

Smallintestine

Membraneenzymes

7-8 AminopeptidaseMaltaseLactaseSucroseAlkaline phosphatase

- Trypsin, chymotrypsin, and carboxypeptidase aresecreted in inactive form by the pancreas

o 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 unitso 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 is absorbed- The large intestine harbors a rich flora of mostly

harmless bacteria

o Escherichia coli - one of the most common

inhabitants of the human colono Many coon bacteria generate gases, including

methane and hydrogen sulfideo Some bacteria produce vitamins, including

biotin, folic acid, vitamin K, and several Bvitamins, which supplement our dietary intake of

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 two

sphincters; one involuntary and one voluntary

o Once or more each day, strong contrac

the colon create an urge to defecate

Regulation of digestion- The length of the vertebrate digestive system

correlated with diet- The most elaborate adaptations for a herbivor

have evolved in the ruminants, which include cattle, and sheep

- The human body regulates the use and storagglucose, a major cellular fuel

Nutritional Requirements- A nutritionally adequate diet satisfies three ne

o

Fuel (chemical energy) for all the cellulaof the bodyo Organic raw materials animals use in

biosynthesis (carbon skeletons to maketheir own molecules)

o Essential nutrients

- If the diet of a person, or other animal is chrondeficient in calories, undernourishment resu

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

- Marasmus, general undernourishment froma in both calories and protein

- Kwashiorkor, a protein malnourishment fromadequate in calories but deficient in protein

- Overnourishment or obesity results from excfood intake

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

o High leptin level cues the brain to de

appetite and to inc energy-consuming mactivity and body-heat production

o Loss of body fat decreases leptin levels

blood, signaling the brain to increase apand weight gain.

Appetite-regulating hormones

- Ghrelin (stomach wall)o Triggers feelings of hunger as mealtime

approach

- 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 br

- animals require 20 amino acids to make prote


7/7

- Essential amino acids must be obtained from food inprefabricated formo Adult humans:

Phenylalanine

Lysine

Isoleucine

Leucine

Valine

Methionine

Tryptophan

Threonineo Histidine and arginine essential for normal

growth 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 diet insmall quantities

- 13 vitamins essential to humans have been identified- Water-soluble vitamins generally fxn as co-enzymes

- Minerals are simple inorganic nutrients, usually reqdin 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

hemoglobino Na, K, Cl major influence on the osmotic

balance 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 Moist

o Thin

o Relatively large- Effectiveness of diffusion is enhanced by

vascularization

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 breathing

Frogo Negative pressure breathing

Mammals

- The volume of air an animal inhales and exhales witheach breath is called tidal volumeo It averages about 500 mL in resting humans

- The max tidal volume during forced breathing is thevital 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 pigmentso Hemocyanin

o 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 formcarbaminohemoglobin

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

- A drop in pH lowers the affinity of hemoglobin for O2,an effect called the Bohr shift

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Bio Lec 3rd Exam Lec Notesila