RBSE Class 11 Biology Notes Chapter 7 Structural Organisation in Animals

These comprehensive RBSE Class 11 Biology Notes Chapter 7 Structural Organisation in Animals will give a brief overview of all the concepts.

RBSE Class 11 Biology Chapter 7 Notes Structural Organisation in Animals

→ Cells, tissues, organs and organ systems split up the work in a way that ensures the survival of the body as a whole and exhibit division of labour.

→ A tissue is defined as a group of cells along with intercellular substances performing one or more functions in the body.

→ Epithelia are sheet like tissues lining the body's surface and its cavities, ducts and tubes, Epithelia have one free surface facing a body fluid or the outside environment. Their cells are structurally and functionally connected at junctions.

→ Diverse types of connective tissues bind together, support, strengthen, protect, and insulate other - tissues in the body.

→ Soft connective tissues consist of protein fibres as well as a variety of cells arranged in a ground substance.

→ Cartilage, bone, blood, and adipose tissue are specialised connective tissues.

 

→ Cartilage and bone are both structural materials. Blood is a fluid tissue with transport functions.

→ Adipose tissue is a reservoir of stored energy.

→ Muscle tissue, which can contract (shorten) in response to stimulation, helps in movement of the body and specific body parts.

→ Skeletal muscle is the muscle tissue attached to bones.

→ Smooth muscle is a component of internal organs.

→ Cardiac muscle makes up the contractile walls of the heart.

→ Connective tissue covers all three types of tissues. 

→ Nervous tissue exerts greatest control over the response of body. Neurons are the basic units of nervous tissue.

→ Earthworm, Cockroach and Frog show characteristic features in body organisation.

→ In Pheretima posthuma (Earthworm), the body is covered by cuticle.

→ All segments of its body are alike except the 14th, 15th and 16th segment, which are thick and dark and glandular, forming clitellum.

→ A ring of S-shaped chitinous setae is found in each segment. These setae help in locomotion.

→ On the ventral side spermathecal openings are present in between the grooves of 5 and 6, 6 and 7, 7 and 8 and 8 and 9 segments.

→ Female genital pores are present on 14th segment and male genital pores on 18th segment.

→ The.alimentary canal is a narrow tube made of mouth, buccal cavity, pharynx, gizzard, stomach, intestine and anus.

→ The blood vascular system is of closed type with heart and valves.

→ Nervous system is represented by ventral nerve cord.

→ Earthworm is hermaphrodite.

→ Two pairs of testes occur in the 10th and 11th segment, respectively.

→ A pair of ovaries are present on 12th and 13th intersegmental septum.

→ It is a protandrous animal with cross- fertilisation.

→ Fertilisation and development take place in cocoon secreted by the glands of clitellum.

→ The body of Periplaneta americana (Cockroach) is covered by chitinous exoskeleton.

→ It is divided into head, thorax and abdomen.

→ Segments bear jointed appendages.

→ There are three segments of thorax, each bearing a pair of walking legs.

→ Two pairs of wings are present, one pair each on 2nd and 3rd segment.

→ There are ten segments in abdomen.

→ Alimentary canal is well developed with a mouth surrounded by mouth parts, a pharynx, oesophagus, crop, gizzard, midgut, hindgut and anus.

→ Hepatic caecae are present at the junction of foregut and midgut.

→ Malpighian tubules are present at the junction of midgut and hindgut and help in excretion.

→ A pair of salivary glands is present near crop.

→ The blood vascular system is of open type.

→ Respiration takes place by network of tracheae. Trachea opens outside with spiracles.

→ Nervous system is represented by segmentally arranged ganglia and ventral nerve cord.

→ A pair of testes is present in 4th-6th segments and ovaries in 2nd-6th segments.

→ Fertilisation is internal.

→ Female produces 9-10 ootheca bearing developing embryos.

→ After rupturing of single ootheca sixteen young ones, called nymphs come out.

→ The Indian bullfrog, Rana tigrina (Frog), is the common frog found in India.

→ Body is covered by skin.

→ Mucous glands are present in the skin which is highly vascularised and helps in respiration in water and on land.

→ Body is divisible into head and trunk.

→ A muscular tongue is present, which is bilobed at the tip and is used in capturing the prey.

→ The alimentary canal consists of oesophagous, stomach, intestine and rectum, which open into the cloaca.

→ The main digestive glands are livdr and pancreas.

→ It can respire in water through skin and through lungs on land.

→ Circulatory system is closed with single circulation. RBCs are nucleated.

→ Nervous system is organised into central, peripheral and autonomic.

→ The organs of urinogenital system are kidneys and urinogenital ducts, which open into the cloaca.

→ The male reproductive organ is a pair of testes.

→ The female reproductive organ is a pair of ovaries.

→ A female lays 2500-3000 ova at a time.

→ The fertilisation and development are external.

→ The eggs hatch into tadpoles, which metamorphosis into frogs.

→ Adipocytes: Lipid storage cells

→ Adipose tissue: specialized areolar tissue rich in stored fat

→ Areolar tissue: (also, loose connective tissue) A type of connective tissue proper that shows little specialization with cells dispersed in the matrix

→ Astrocyte: Star-shaped cell in the central nervous system that regulates ions and uptake and/or breakdown of some neurotransmitters and contributes to the formation of the blood-brain barrier

→ Basement membrane: In epithelial tissue, a thin layer of fibrous material that anchors the epithelial tissue to the underlying connective tissue; made up of the basal lamina and reticular lamina

→ Cardiac muscle: Heart muscle, under involuntary control, composed of striated cells that attach to form fibers, each cell contains a single nucleus, contracts autonomously

→ Cell junction: Point of cell-to-cell contact that connects one cell to another in a tissue

→ Chondrocytes: Cells of the cartilage

→ Clotting: Also called coagulation; complex process by which blood components form a plug to stop bleeding

→ Collagen:    Flexible fibrous protein that give connective tissue tensile strength

→ Connective tissue membrane: Connective tissue that encapsulates organs and lines movable joints

→ Connective tissue proper: Connective tissue containing a viscous matrix, fibers, and cells.

→ Connective tissue: Type of tissue that serves to hold in place, connect, and integrate the body's organs and systems

→ Cutaneous membrane: Skin; epithelial tissue made up of a stratified squamous epithelial cells that cover the outside of the body

→ Dense connective tissue: Connective tissue proper that contains many fibers that provide both elasticity and protection

→ Ectoderm: Outermost embryonic germ layer from which the epidermis and the nervous tissue derive

→ Elastic cartilage: Type of cartilage, with elastin as the major protein, characterized by rigid support as well as elasticity

→ Elastic fiber: Fibrous protein within connective tissue that contains a high percentage of the protein elastin that allows the fibers to stretch and return to original size

→ Endocrine gland: Groups of cells that release chemical signals into the intercellular fluid to be picked up and transported to their target organs by blood

→ Endoderm: Innermost embryonic germ layer from which most of the digestive system and lower respiratory system derive

→ Endothelium: Tissue that lines vessels of the lymphatic and cardiovascular system, made up of a simple squamous epithelium

→ Epithelial membrane: Epithelium attached to a layer of connective tissue

→ Epithelial tissue: Type of tissue that serves primarily as a covering or lining of body parts, protecting the body; it also functions in absorption, transport, and secretion

→ Exocrine gland: Group of epithelial cells that secrete substances through ducts that open to the skin or to internal body surfaces that lead to the exterior of the body

→ Fibroblast: Most abundant cell type in connective tissue^ secretes protein fibers and matrix into the extracellular space

→ Fibrocartilage: Tough form of cartilage, made of thick bundles of collagen fibers embedded in chondroitin sulphate ground substance

→ Fibrocyte: Less active form of fibroblast

→ Fluid connective tissue: Specialized cells that circulate in a watery fluid containing salts, nutrients, and dissolved proteins

→ Gap junction: Allows cytoplasmic communications to occur between cells

→ Goblet cell: Unicellular gland found in columnar epithelium that secretes mucous

→ Ground substance: Fluid or semi-fluid portion of the matrix

→ Histology: Microscopic study of tissue architecture, organization, and function

→ Hyaline cartilage: Most common type of cartilage, smooth and made of short collagen fibers embedded in a chondroitin sulfate ground substance

→ Lacunae: (singular = lacuna) Small spaces in bone or cartilage tissue that cells occupy

→ Lamina propria: Areolar connective tissue underlying a mucous membrane

→ Loose connective tissue: (also, areolar tissue) Type of connective tissue proper that shows little specialization with cells dispersed in the matrix

→ Matrix: Extracellular material which is produced by the cells embedded in it, containing ground substance and fibers

→ Mesenchymal cell: Adult stem cell from which most connective tissue cells are derived

→ Mesenchyme: Embryonic tissue from which connective tissue cells derive

→ Mesoderm: Middle embryonic germ layer from which connective tissue, muscle tissue, and some epithelial tissue derive

→ Muscle tissue: Type of tissue that is capable of contracting and generating tension in response to stimulation; produces movement.

→ Myelin: Layer of lipid inside some neuroglial cells that wraps around the axons of some neurons

→ Myocyte: Muscle cells 

→ Nervous tissue: Type of tissue that is capable of sending and receiving impulses through electrochemical signals.

→ Neuroglia: Supportive neural cells & Neuron: Excitable neural cell that transfer nerve impulses

→ Oligodendrocyte: Neuroglial cell that produces myelin in the brain

→ Reticular fiber: Fine fibrous protein, made of collagen subunits, which cross-link to form supporting "nets" within connective tissue

→ Reticular lamina: Matrix containing collagen and elastin secreted by connective tissue; a component of the basement membrane

→ Reticular tissue: Type of loose connective tissue that provides a supportive framework to soft organs, such as lymphatic tissue, spleen, and the liver

→ Schwann cell: Neuroglial cell that produces myelin in the peripheral nervous system

→ Simple columnar epithelium: Tissue that consists of a single layer of column-like cells; promotes secretion and absorption in tissues and organs

→ Simple cuboidal epithelium: Tissue that consists of a single layer of cube-shaped cells; promotes secretion and absorption in ducts and tubules

→ Simple squamous epithelium: Tissue that consists of . a single layer of flat scale-like cells; promotes diffusion and filtration across surface

→ Skeletal muscle: Usually attached to bone, under voluntary control, each cell is a fiber that is multinucleated and striated 

→ Smooth muscle: Under involuntary control, moves internal organs, cells contain a single nucleus, are spindle-shaped, and do not appear striated; each cell is a fiber

→ Stratified columnar epithelium: Tissue that consists of two or more layers of column-like cells, contains glands and is found in some ducts

→ Stratified cuboidal epithelium: Tissue that consists of two or more layers of cube-shaped cells, found in some ducts

→ Stratified squamous epithelium: Tissue that consists of multiple layers of cells with the most apical being flat scale-dike cells; protects surfaces from abrasion

→ Striation: Alignment of parallel actin and myosin filaments which form a banded pattern

→ Supportive connective tissue: Type of connective tissue that provides strength to the body and protects soft tissue

→ Tissue membrane: Thin layer or sheet of cells that covers the outside of the body, organs, and internal cavities 

→ Tissue: Group of cells that are similar in form and perform related functions

→ Aboral: In a direction away from the mouth; the part of the body opposite to the mouth.

→ Acicula: Needle like bristles within parapodium of polychaete.

→ Adaptations: The fitness of an organism for its environment.

→ Appendages: Portion of body that projects and has a free end such as limbs.

→ Arms: Long, flexible mobile limbs - usually containing a feeding groove.

→ Arthropoda: An invertebrate animal having an exoskeleton, a segmented body, and jointed appendages.

→ Bilaterally symmetrical: The arrangement of the body parts so that the right and left halves are mirror images of each other.

→ Blastomeres: A type of cell produced by cleavage of the zygote after fertilization which is an essential part of blastula formation.

→ Cerebral ganglia: In invertebrates, one' of a pair of ganglia (or fused median ganglion) situated in the head or anterior portion of the body.

→ Chitin: A complex organic substance or a polysaccharide protein, forming the exoskeleton of arthropods and some other animals.

→ Cleavage: Series of early divisions of an egg into many cells.

→ Clitellum: A thickened glandular portion of the body of an earthworm or other annelid, used in the formation of cocoon.

→ Coelom: A body cavity (fluid filled), formed in the embryo.

→ Columnar epithelial cells: Epithelial cells whose heights are atleast four times their width.

→ Corpuscles: A minute body or cell in an organism, especially a red or white cell in the blood of vertebrates.

→ Cosmopolitan: Of universal occurence.

→ Dermo-muscular: Pertaining to skin and muscles.

→ Ectoderm: The outer of the three germ layers of the embryo.

→ Embryology: The study of the development of an organism.

→ Endoderm: The innermost of the three primitive germ layers of the embryo.

→ Endoskeleton: An endoskeleton is an internal support structure of an animal, typically made of bone.

→ Epidermis: The outer cellular layer of the cells covering the external surface of the body.

→ Excretory system: is a passive biological system that removes excess, unnecessary materials from the body fluids of an organism, so as to help in maintain internal chemical homeostasis and prevent damage to the body.

→ Fertilization: Union of a male gamete (sperm) with a female gamete (ovum) to give an egg, or zygote.

→ Ganglia: Group of mass of nerve cell bodies.

→ Gastrulation: Process by which cells of the blastoderm are translocated to new positions in the embryo, producing the three primary germ layers.

→ Habitat: Environment in which an animal lives.

→ Haemocoelomic: A body cavity (as in arthropods or some molluscs) that normally contains blood and functions as part of the circulatory system.

→ Haemoglobin: Is the protein molecule in red blood cells that carries oxygen from the lungs to the body's tissues and returns carbon dioxide from the tissues back to the lungs.

→ Hermaphroditic: An individual possessing both male and female reproductive organs.

→ Locomotary: Related to the movement of an organism.

→ Macrolecithal: Eggs with a large yolk.

→ Metamerism: Conditions where the body of an animal is made up of a succession of homologous parts.

→ Microlecithal: An egg containing a little amount of yolk.

→ Nephridia: An invertebrate organ which occurs in pairs and performs a function similar to the vertebrate kidney.

→ Oral: In a direction toward the mouth; a part of the body .on the same surface as the mouth.

→ Ovary: One of the paired female reproductive organs that produce eggs.

→ Parapodium: Flattened, Paired appendages on the body segments of many polychaete annelids that help in locomotion.

→ Pedicellariae: Small stalked or unstalked pincer-like organs on the body of asteroids and echinoids, used for defense and grooming.

→ Peristomium: The second body segment in an annelid worm's body in the anterior end. It is directly behind the prostomium and contains the mouth.

→ Pharynx: Anterior portion of the digestive tract between mouth cavity and oesophagus.

→ Photoreceptor cells: Light sensitive cells or organs.

→ Proboscis: Tubular extension of the nose, lips or pharynx, the extended beaklike mouth parts of insects.
 
→ Prostomium: Anterior portion of the first segment of the annelids such as earthworms overhanging the mouth region.

→ Pygidium (plural pygidia): The posterior body part or shield of crustaceans and some other arthropods, such as insects and the extinct trilobites. It contains the anus and, in females, the ovipositor.

→ Regeneration: Replacement by growth of a part of body that has been lost.

→ Schizocoelous: Body cavity formed by the splitting of the embryonic mesoderm.

→ Segmented worms: Annelids.

→ Setae or chaetae: Bristles those embedded in the body wall of the earthworm.

→ Spermatheca: Seminal receptacles in some female insects.

→ Statocysts: Organs of equilibrium and balance in some animals like Palaemon.

→ Tentacles: In holothuroids, feeding structures in the form of highly modified tube feet arranged in a ring around the mouth.

→ Testis: A male gonad.

→ Triploblastic: Derived from three primary germ layer- ectoderm, mesoderm and endoderm.

→ Valve: A structure that limits or closes in opening.

→ Vascular system: Also called the circulatory system is made up of the vessels that carry blood and lymph through the body.

→ Amphibians: A group of vertebrates including frogs, salamanders and caecilians. Amphibians usually have aquatic larvae and terrestrial adults.

→ Advertisement Calls: Calls used by frogs to define their territories and to attract female frogs during breeding season.

→ Aggressive Calls: Males usually make these calls, when other males are trying to occupy their territory or are very close to their territory.

→ Amplexus: Sexual embrace of amphibians; the grasping of the female's body by the males forelimbs from a dorsal position. The grip is strong, and is not released until oviposition is completed. There are two principal types: axillary (pectoral), in which the grip is just behind the forelimbs, and inguinal (pelvic), with the grip just before the hindlimbs.

→ Barbels: A fleshy, tubular extension of the skin, usually on the head or the neck, which appear to be sensory, probable tactile in function.

→ Brumation: Time period when frogs and other ectotherms become inactive, if they hide in a leaf litter or take refuge in ponds to cope with the cold, dry and harsh temperatures. 

→ Brachial: Pertaining to or located on the upper or the humeral part of the forelimb.

→ Call: The noise, cry, whistle or song of an anuran, usually confined to males. In a very few species, the female has a voice.

→ Courtship Calls: Calls that are given by both males and females just before amplexus.

→ Cloaca: The common chamber into which the intestinal, urinary and reproductive duct discharge their contents, opening to the outside through the anus.

→ Choana: Internal opening of the nasal passage in the roof of the mouth (plural: choanae).

→ Defensive calls: The adults of both sexes and juveniles make these calls when attacked by the potential predator.

→ Eclosion: The emerging of an insect from the pupa case or the emergence of larva from the egg.

→ Guttural Resonator: Referring to the sound coming out of throat; harsh sound.

→ Holotype: The specimen that is the legal bearer of the name of the species, according to the International Code of Zoological Nomenclature.

→ Interorbital: The measurement between the eyes, usually taken across the top of the head.

→ Larva: An embryo which becomes self-sustaining and independent before it has acquired the characteristic features of its parents.

→ Labia: Lip-like structure.

→ Metamorphosis: The process of changing from one form to another during development. In amphibians it is usually associated with a switch from an aquatic larval stage to a terrestrial adult phase.

→ Metapodials: Any one of the bones of a limb lying between the mesopodials and phalanges; the long bones making up the proximal part of a digit, lying in the fleshy part of the foot. There are two types: metacarpals and metatarsals.