BIO 3 Handout

BIO 3 HANDOUT ANIMAL TISSUES A. Epithelial tissues -lining of the surfaces -selectively permeable -regenerates (in liver and stomach the tissues are replaced every 2-3 days) -simple epithelial cells (squamous, cuboidal, columnar)

Intestinal columnar cells B. Vascular tissues BLOOD -circulates throughout the body -carries nutrients and oxygen or wastes -made up of different components:

Cheek squamous epithelial cells

  Collecting ducts in the medulla of a mammalian kidney lined with simple cuboidal cells



Plasma-water-containing fluid Platelets (thrombocytes)function for blood clotting White blood cells (leukocytes)- has different types (neutrophil, basophil and eosinophil) ; function for immune response

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Neutrophil- against bacteria; inflammatory reactions

Basophil- responsible for allergic reactions

Eosinophil- responsible for immune response against parasites 

Red Blood Cells (erythrocytes)with hemoglobin; carrier of oxygen

T cell (blue)- attack foreign bodies as a principal mean of defense

B cell (arrow)- responsible for the production of antibodies CONNECTIVE TISSUE PROPER -with abundant matrix (extracellular materials) -Adipose cells/ fat cells/ adipocytes  important for nutrient storage  found under the skin, bone marrow, around the kidneys, hips and breasts  within the cells are fat droplets (triglycerides)  incapable of dividing (increase in body weightcells swell) -Tendon (muscle to bone) and Ligament (bone to bone)

Enucleated human RBC’s 

Lymph (lymphocytes: T cells and B cells) – for the immune system Adipose cells

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CARTILAGE -cells: chondrocytes within the lacuna -composed of glycoproteins: chondroitin and collagen fibers -high tensile strength -found at (joints) surfaces of bones -tip of nose, pinna (ear), larynx or voice box

Cardiac Muscle -location:walls of the heart -highly interconnected cells promote rapid spread of signal initiating contraction

Chondrocytes BONE -calcified cartilage phosphate) -cells: osteocytes

Haversian system Canaliculi (arrow)

Skeletal Muscle -location: voluntary muscles -function: powers walking, lifting, dancing…

(calcium

(bracket);

NERVE TISSUE Neurons -capable of events: IMPULSES -parts:

electrochemical

MUSCLE TISSUE Smooth Muscle -location: walls of blood vessels, stomach, intestines -function: powers rhythmic involuntary contractions

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-RADIAL symmetry- exhibited by marine animals: Cnidarians (jellyfishes, sea anemones and corals) and Ctenophorans (combjellies).

Cross section of a nerve

Jellyfish

sea anemone

THE GENERAL BODY PLAN OF ANIMALS -Kingdom animalia is the most diverse group of organisms. One of the reasons is the differences in the general body plan. Throughout the evolution of animals, their body plans have undergone many changes: Evolution of Tissues -simplest animals like Parazoas (sponges) exist as simply aggregates of cells with minimal intercellular coordination.

Corals -BILATERAL symmetry- right and left mirror images; concept of dorsal/ventral, anterior end/ posterior end; allowed animals to: -move more efficiently -have different organs located in different parts of the body -produce 3 germ layers: ectoderm-outer coverings, mesoderm-skeleton and muscles, and endodermdigestive organs -cephalization

-eumetazoa (all higher animals), have distinct tissues with highly specialized cells. Evolution of Bilateral Symmetry -sponges lack symmetry

Evolution of Body Cavity

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-evolved for supporting organs, and distributing materials - 3 kinds of body plans: Acoelomates -no body cavity -flatworms: tapeworms, flukes and planarians

Tapeworm

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and in locomotion, each segment can move independently. Segmentation—METAMERISM: each segment is similar to the other (somites/metameres). TAGMATIZATION: segments fused into functional groups (tagmata)

Liver Fluke clitellum Pheretima (earthworm) Planarian

Pseudocoelomates -with a body cavity- pseudocoel -between mesoderm and endoderm -nematodes: Ascaris Linkia (starfish)

Evolution of Segmentation - subdivision of the body into segments - advantages: (annelids) damage in one segment is not fatal (duplication of segment functions)

Penaeus (shrimp)

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shape and produces movement (peristaltic movement - squeezing other segments while allowing others to relax)

Periplaneta Americana

Bufo marinus

ORGAN SYSTEMS

Exoskeleton -skeletons which encases the organisms body -exhibited by insects, crustaceans and spiders -composed of CHITIN (light, strong for protection and reduction of water loss); -can be calcified for further strengthening

THE PROTECTIVE AND SUPPORT SYSTEMS OF ANIMALS Main functions: to provide support, protection and enable movement of different skeletal forms: Hydrostatic Skeleton -exhibited by mollusks and nematodes/ worms -pressurized fluid in compartments and by using the muscles surrounding these compartments, the animal changes BIO3 TJMedina ‘08

Euplectella (Venus’ basket) – the skeleton is made up of silica Endoskeleton -found within the body of the animal -vertebrates (bones) and echinoderms (ossicles) – calcium rich -2 sections: axial skeleton and appendicular skeleton

DIGESTIVE SYSTEM

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Types of Digestive Tracts (Guts) Incomplete Gut -single opening: mouth -Planarian, Cnidarian, Nematodes -gastrovascular cavity: mouth, pharynx, intestine -extracellular digestion: circulation of food by diffusion -no specialization of parts Complete Gut -two openings: mouth and anus -with specialization of parts:  pharynx-draws in food with a sucking action  gizzard- thick muscular walls for churning and grinding of food  cloaca- storage of undigested materials, urine, and products of the reproductive system  cecum- with bacteria; aids the digestion of cellulose; located at the beginning of the large intestine; more prominent in ruminants/ herbivores  accessory organs: -liver—produces bile (green solution that emulsifies fats) -gall bladder—stores and concentrates bile -pancreas— release digestive enzymes and bicarbonate buffers to aid digestion

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EXCRETORY SYSTEM Planaria/ Flat worms -PROTONEPHRIDIA (tubules) which branchout into bulb-like FLAME CELLS -cilia within the flame cells draw in fluids from the body -the wastes are expelled through excretory pores that open outside the body Annelida/ Round worms -NEPHRIDIA (tubules) obtain fluid from body cavity by filtration of NEPHROSTOMESpore for urine excretion (urine is diluted; NaCl is reabsorbed) -in Mollusks (kidney) and Crustaceans (antennal glands)- urine produced from filtration; ions are reclaimed by reabsorption

Uric acid- from reptiles, birds and insects; slightly soluble in water; in solid form, excreted with little water (helps in reduction of water loss) In most mammals, there is an enzyme: URICASE which convert uric acid to allantoin, a less toxic substance, but humans, apes, and Dalmatian dogs do not have it. The excessive deposits of uric acid can cause: Gout. CIRCULATORY SYSTEM 3 principal functions of C.S.: Transportation – nutrients and oxygen Regulation – transport of regulatory hormones Protection – blood clotting and immune defense Types of Circulatory Systems

Insects -MALPHIGIAN TUBULES which branch off anterior to the hindgut -waste products and potassium ions are secreted into tubules by active transport -most water and K+ are reabsorbed; dry waste product excreted from the rectum Vertebrates -kidney—NEPHRONS NITROGENOUS WASTES: Ammonia- can be toxic to cells; released in a diluted form by bony fishes and tadpoles Urea- excreted by adult amphibians, mammals; soluble in water and can be excreted in large amounts; from bloodstream to liver, then kidneys and excreted as urine

For Cnidarians, Flatworms/ Planarians which have two layers of body wall, have direct contact with the external environment that transport can occur by diffusion. Open Circulatory System -exhibited by mollusks and arthropods -no distinction between the circulating fluid (blood) and extracellular fluid (interstitial fluid/lymph): HEMOLYMPH -heart is a muscular tube which pumps hemolymph through a network of channels and cavities in the body -fluid drains back to the central cavity

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Closed Circulatory System -exhibited by annelids (invertebrates) and all vertebrates -circulating fluid (blood) is enclosed in blood vessels

Fishes-have true chamber-pump heart: sinus venosus and atrium (collection chambers); ventricle and conus arteriosus(pumping chambers)

a-artery(away from the heart); b-capillary; cvein (back to the heart)

Earthworm -dorsal vessel contracts to function as pump -blood is pumped through 5 small connecting arteries which function as pumps to a ventral vessel (transport posteriorly until it re-enters dorsal vessel

Toad heart has three chambers: right and left atria, and a ventricle. Amphibian and Reptile Circulation 2 types: Pulmonary Circulation - heart to lungs, then back to heart - pulmonary artery-lungs-pulmonary vein-heart Systemic Circulation - heart to body organs, then back to heart

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Mammalian and bird hearts are four-chambered. RESPIRATORY SYSTEM

Fishes have gills wherein water passes from the gill arch and over the filaments. Water always passes the lamellae in an opposite direction of blood flow. The success of the gill’s operation is dependent on the countercurrent flow of blood and water.

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In amphibian lungs, each lung is an outpouching of the gut. It is filled with air by the creation of a positive pressure inside the buccal cavity. Their lungs are not as efficient as the lungs of other terrestrial vertebrates because they lack structures that would increase the surface area of the lungs for gas exchange. NERVOUS SYSTEM

Evolution of the Nervous System. Animals exhibit a progressive elaboration of organized nerve cords and the centralization of complete responses in the front end of the nerve cord. This evolutionary process is known as CEPHALIZATION.

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ENDOCRINE SYSTEM

Evolution of Vertebrate Brain. In sharks and other fishes, the hindbrain is predominant, which primarily is used to process sensory information. For amphibians and reptiles, the forebrain is more dominant as the cerebrum becomes bigger. It is devoted to associative activity. In birds and mammals, especially humans, the largest portion of the brain is the cerebrum.

An adult insect emerging from an old cuticle

Insects’ exoskeleton cannot expand as the organism grows, this is the reason they undergo molting. This process is initiated to occur because of hormones released by endocrine glands.

Reflex Action

References: Raven et. al. 2005. BIOLOGY. 7th ed. McGraw Hill Company. Boston. Mader S.S. 1998. BIOLOGY. 6th ed. McGraw Hill Company. Boston. Pp 716-912.

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-exhibited by:  Flatworms—TRANSVERSE FISSION  Cnidarians—BUDDING from parent  Echinoderms—cut to form new individuals  Insects—PARTHENOGENESIS (females produce offsprings from unfertilized eggs  Some fishes—SEQUENTIAL HERMAPHRODISM (protogynyfemale at first, then change to a male; protoandry- male then becomes a female) SEXUAL REPRODUCTION -fusion of two gametes -variation is achieved: exchange of genetic content

Anatomy of Planarians

ANIMAL REPRODUCTION -all animals have a DIPLONTIC life cycle, the only haploid cells are the SEX CELLS or GAMETES -reproduction is very essential for the survival of species and the creation of diversity (variation). 2 types: ASEXUAL REPRODUCTION -involves 1 parent genotype: no variation)

(same

2 types of Fertilization EXTERNAL FERTILIZATION -many gametes released in water -animal sperm must swim to eggs INTERNAL FERTILIZATION -for animals that lay shelled eggs/ have a period of internal embryonic development -for terrestrial animals which can enable their sperm to swim without drying out -males have special organs used for transferring sperm: process: COPULATION -gametes are produced in GONADS by the process called GAMETOGENESIS which occurs when the organism is sexually matured -sperm cell / spermatozoa production —SPERMATOGENESIS -egg cell/ ova production— OOGENESIS -FERTILIZATION: activation of the egg (entry of sperm) + AMPHIMIXIS (fusion of egg and sperm nuclei)

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