Protection, Support, and Movement (Zoology) PDF

Protection, Support, and Movement ZOOLOGY Integument protective outer covering of the animal body. includes skin and structures associated with the skin (derivatives of the skin) such as hair, nails, scales, feathers, and horns ZOOLOGY  Functions of the Integument 1...

Protection, Support, and Movement ZOOLOGY Integument protective outer covering of the animal body. includes skin and structures associated with the skin (derivatives of the skin) such as hair, nails, scales, feathers, and horns ZOOLOGY  Functions of the Integument 1. Protection from mechanical and chemical injury 2. Protection against invasion by microorganisms 3. Regulation of body temperature 4. Excretion of waste materials 5. Vitamin D production 6. Reception of environment stimuli 7. Locomotion/movement 8. Controls movement of nutrient and gas ZOOLOGY Invertebrate Integument Some single-celled protozoa have only a plasma membrane for external covering (Amoeba) Other protozoa have a thick protein coat pellicle outside the plasma membrane (Paramecium) Most multicellular have invertebrates have a single- layered epidermis covering the body (nematodes, annelids) ZOOLOGY Invertebrate Integument Others have added a secreted non-cellular cuticle over the epidermis (crustaceans, arachnids, insects) additional protection old cuticles need to shed periodically in a process called molting to permit growth ZOOLOGY Invertebrate Integument Molluscs have a delicate epidermis Protection is provided by the shell Cephalopods have a more complex epidermis with cuticle, simple epidermis, layer of connective tissue. Arthropods have a complex integument that provides protection and skeletal support. Single layered epidermis (hypodermis) which secretes a complex cuticle Procuticle - layers of chitin and protein Epicuticle - moisture proofing barrier ZOOLOGY Invertebrate Integument The arthropod cuticle may remain tough, but flexible as in many small crustaceans and insect larvae, or it may become hardened. Decapod crustaceans have a cuticle stiffened by calcification deposition of calcium carbonate in the procuticle In insects, hardening occurs by sclerotization where protein molecules bond together producing the insoluble protein sclerotin. ZOOLOGY Other examples of Invertebrate Integument Rotifers - cuticles are thin and elastic Arthropods - cuticles are thick and rigid Cnidarians - epidermis is only a few cell layers Rotifers thick (Hydra), contains mucous glands that secrete calcium carbonate shells (corals) Arthropods Cnidarians ZOOLOGY Other examples of Invertebrate Integument Platyhelminthes - covering is a tegument functions for nutrient ingestion and protection Nematodes and annelids - have an epidermis that is one cell Platyhelminthes Nematodes thick and secretes a multilayered cuticle Echinoderms - integument consists of thin, ciliated epidermis and an underlying connective tissue dermis that Annelids Echinoderms contains calcium carbonate ZOOLOGY Vertebrate Integument Skin vertebrate integument largest organ Skin has 2 main layers: Epidermis (outer layer) Dermis (Inner layer) Each with specialized cells and structures adapted to the needs of the organisms Annelids ZOOLOGY Epidermis gives rise to hair, feathers, scales, fur, and glands. outermost layer of skin in vertebrates, acting as the body's first line of defense against environmental factors thin outer stratified epithelial layer, derived from ectoderm Dermis inner layer of skin located beneath the epidermis, providing structural support and housing various structures essential for skin function. thick inner layer, derived from mesoderm contains blood vessels, nerves, hair follicles, and glands. ZOOLOGY The Skin of Cartilaginous Fishes The epidermis contains mucous cells that produce slippery secretion, reducing friction and providing protection against pathogens. The dermis (thicker layer) is rich in collagen and contains dermal denticles tiny, tooth-like structures that enhance hydrodynamics, allowing for smoother movement through water When they grow throughout life, the skin area also increases. New denticles are produced to maintain enough of these protective structures of the skin surface. ZOOLOGY The Skin of Bony Fishes Contains scales composed of dermal bone Scales are not shed, they grow at margins and over the lower surface. Permeable and function in gas exchange Epidermis contains mucous glands that secrete a slimy layer, reducing friction while swimming and providing additional protection against pathogens. Dermis is richly supplied with a capillary beds to facilitate its use in respiration. networks of tiny blood vessels (capillaries) located within the dermis and other tissues. presence of capillaries also aids in the absorption of oxygen from the water, particularly through specialized structures like the gills. ZOOLOGY The Skin of Amphibians Transitional between aquatic and terrestrial vertebrates The epidermis is composed of epithelial cells Protection against pathogens Mucous cells keep skin moisture for respiration Granular cells produce toxins for defense The dermis is made of connective tissue Provides structural support and elasticity. within dermis of some amphibians are poison glands that produce unpleasant tasting or toxic fluid that acts as predator The epidermis relies on the dermis for nutrients and structural integrity, essential for the amphibian's survival. Three problems associated with terrestrial environments: Desiccation Damaging effects of UV light Physical abrasion ZOOLOGY The Skin of Amphibians During amphibian evolution, keratin production increases in the outer layer of skin cells Keratin is a tough and impermeable protein that protects the skin in the physically abrasive rigorous terrestrial environment. The mucous glands produce mucus helps prevent desiccation facilitates gas exchange makes body slimy facilitates escape from predators ZOOLOGY The Skin of Reptiles The outer layer of epidermis (stratum corneum) is thick, lack glands, and is modified into keratinized scales - scutes. thick scales The thick, keratinized layer resists abrasion, inhibits dehydration, and protects like a suit of armor. During shedding or molting of the skin of many reptiles, the outer layer separates from newly formed epidermis. Reptilian skin is adapted to conserve moisture and protect against environmental challenges, aiding in their survival in diverse habitats. ZOOLOGY The Skin of Birds Shows typically reptilian features with no epidermal glands Epidermis is usually thin and only two or three cell layers thick Most prominent part of epidermis are the feathers (made up of keratin) which develop from specialized structures in the skin. The dermis supports the feathers and houses structures like oil glands that help waterproof the feathers. Air spaces that are part of avian respiratory system extend into the dermis Feather position is important in thermal regulation, flying, and behavior. ZOOLOGY The Skin of Mammals The notable features of mammalian skin are: highly stratified, cornified epidermis dermis with blood and lymphatic vessels, nerve endings, small muscles, glands, hair follicles hypodermis composed of loose connective tissue, adipose tissue and skeletal muscles - the hypodermis attaches the skin to the underlying muscles. The thickest portion of mammalian skin is composed of dermis which contains: Blood vessels, lymphatic vessels, nerve endings, hair follicles, small muscles, and glands. Sweat Glands Different types prevent overheating of the body; secrete sweat, cerumen, and milk Eccrine sweat glands - found in palms, soles of the feet, and forehead Apocrine sweat glands - found in armpits, groin, and genital area. Ceruminous glands - modified apocrine glands in external ear canal that secrete cerumen Mammary glands - specialized sweat glands that secrete milk located in the breast ZOOLOGY Sebaceous Glands Simple alveolar glands found all over the body Soften skin when stimulated by hormones Secretes an oily secretion called sebum Sebaceous glands produce an oily substance called sebum to lubricate the skin and hair follicles, while sweat glands secrete sweat, a watery fluid, primarily used to regulate body temperature by evaporating from the skin surface; essentially, sebaceous glands focus on skin lubrication, whereas sweat glands focus on thermoregulation ZOOLOGY Skin Receptors found in the skin that detects changes in the external environment Meissner’s corpuscles - touch receptors Pacinian corpuscles - pain receptors Ruffini’s corpuscle - heat receptors End Bulbs of Krause - cold receptors Merkel’s disk - texture and touch receptors ZOOLOGY Strctures associated with Skin Hair composed of keratin- filled dead cells that developed from epidermis Nails like hair, are modifications of the epidermis flat, horny plates on the dorsal surface of the distal segments of the digits dorsal - back ZOOLOGY Support and Movement: Skeletal System Skeleton is the hardened part of the animal body Supports the body Framework of the body Protects Vital organs of the body Blood cell formation/hematopoiesis Site for the attachments of muscles Accessory to movement Storage of minerals ZOOLOGY Movement and Support: Skeletal System Four cell types contribute to movement: Amoeboid cells - can change their shape and move using pseudopods, or false feet Flagellated cells - hair-like appendages that help with locomotion and feeding Ciliate cells - cells that have many cilia, which are hair-like organelles that help with movement Muscles cells - specialized cells that contract to produce movement With respect to support, organism have three kind of skeletons: Fluid hydrostatic skeletons Rigids exoskeletons Rigid endoskeletons ZOOLOGY Skeletal System Hydrostatic skeleton type of skeleton that uses fluid pressure to support the body wall and transmit force to generate body movement found in many organisms, including soft-bodied invertebrates like earthworms and sea anemones alternate contractions of circular and longitudinal muscles of the body wall enable a worm to move forward ZOOLOGY Skeletal System ZOOLOGY Skeletal System Rigid Skeletons Rigid skeletons contain some kind of rigid elements Provide anchor points for pairs of opposing muscles Provides protection and support Exoskeleton - external covering; found in molluscs, arthropods, some invertebrates and vertebrates Endoskeleton - an internal skeleton; found in echinoderms, sponges, and chordates ZOOLOGY Skeletal System ZOOLOGY Skeletal System Vertebrate Endoskeleton The vertebrate endoskeleton is composed of bone and cartilage (types of connective tissue) Bone provides support, protection, and serves as a reservoir for calcium and phosphorus. ZOOLOGY Skeletal System Cartilage soft, pliable tissue that resists compression and is varaible in form Jawless fishes (eels, hagfishes) and elasmobranchs (sharks, sting rays) have cartilaginous skeletons Most vertebrates have bony skeletons with sone cartilaginous parts provides site for muscle attachment, aids in movement at joints, provides support, and transmits the force of muscular contraction from one part to the body to another during movement consists of cells, fibers, and cellular matrix. does not contain blood vessels often found at articulating surfaces of many bone joints, larynx, trachea, vertebral column, nose, pinnae, and Eustachian tube. ZOOLOGY  Slippery and smooth Skeletal System which helps your bones Cartilage move smoothly past each other in your joints Most flexible cartilage. It supports parts of your body that need to bend and move to function. Elastic cartilage can bounce back to its original shape Very strong. Act as a cushion within joints, where it helps manage compression forces and reduces stress placed on joints. ZOOLOGY Skeletal System Bone - Dynamic tissue - undergoes continuous remodeling throughout an organism's life Osteoclasts - bone destroying/resorbing cells Osteoblasts - bone forming/building cells Both processes occur together so that new osteons are formed as old ones are resorbed. Hormones (parathyroid hormone for resorption and calcitonin for deposition) are responsible for maintaining a constant calcium level in the blood. ZOOLOGY Skeletal System The Skeleton of Fishes Both cartilaginous and bony endoskeletons first appeared in the vertebrates Water has a buoyant effect on the fish body, the requirement for skeletal support is not as demanding in these vertebrates as it is in terrestrial vertebrates. Most jawed fishes have an axial skeleton that includes a notochord, ribs, and cartilaginous or bony vertebrae. Fishes often have a streamlined body shape supported by their skeletons, allowing for efficient movement through water. The skeletal structure also supports fins, which are crucial for locomotion, balance, and steering in the aquatic environment. ZOOLOGY Skeletal System The Human Endoskeleton Two major parts: Axial skeleton - made up of the skull, vertebral column, sternum, and ribs. Appendicular skeleton - is composed of the appendages, the pectoral girdle, and the pelvic girdle. ZOOLOGY Skeletal System ZOOLOGY Skeletal System Bone classification by shape Long Short Flat Irregular Sesamoid ZOOLOGY Skeletal System Bone classification by shape Long bones - longer than they are wide and work as levers. Bone of lower and upper extremities Humerus Tibia Femur Ulna Metacarpals etc. ZOOLOGY Skeletal System Bone classification by shape Short bones - short, cube- shaped, and found in the wrist and ankles. Tarsal Carpal etc. ZOOLOGY Skeletal System Bone classification by shape Flat bones - have broad surfaces for protection of organs and attachment of muscles Example: Cranial bones Ribs Bones of hip Shoulder girdles ZOOLOGY Skeletal System Bone classification by shape Irregular bones - all that do not fall into the previous categories. They have varied shapes, sizes, and surface features and include bone of the vertebrae and a few in the skull. ZOOLOGY Movement Animal Movement Most animal movement depends on contractile proteins which can change their shape to relax or contract these fibrils will contract when powered by ATP Actin and myosin form a contractile system found in most animals Cilia and flagella utilize different proteins called tubulin. ZOOLOGY Movement Amoeboid Movement found in amoebas, white blood cells, and embryonic cells movement using pseudopods (false feet) depends on actin and myosin ZOOLOGY Movement Cilia found throughout the animal kingdom (except in nematodes, rare in arthropods) Uniform in diameter (0.2-0.5 μm) Basal body similar to a centriole - 9 triplets of microtubules composed of the protein tubulin. Cilium has 9 pairs surrounding two individual microtubules ZOOLOGY Movement Flagellum whiplike structure longer than a cilium and usually present in singly structure is the same different beating pattern ZOOLOGY Movement Muscular Movement muscle cell (muscle fibers) can only do work by contraction they can’t actively lengthen often arranged in opposing (antagonistic) pairs Three types of muscle tissue: Skeletal Smooth Cardiac ZOOLOGY Movement Skeletal Muscle Skeletal, (striated) muscle appears to be striped multinucleate fibers attached to skeleton voluntary fast acting, but fatigues quickly. ZOOLOGY Movement Smooth Muscle Smooth muscle lack striations Fusiform cells with a singe, oval nucleus Involuntary Slow acting, but can maintain prolonged contractions Muscles of the stomach, intestines, uterus are smooth muscle ZOOLOGY Movement Cardiac Muscle Found only in the heart, is striated and fast acting like skeletal muscle Involuntary, with one or two nucleus per fiber Fibers are joined by junctional complexes called intercalated discs ZOOLOGY Movement Muscle A skeletal muscle consists of bundle of long fibers running parallel to the length of the muscle A muscle fiber is itself a bundle of smaller myofibrils arranged longitudinally ZOOLOGY Movement Muscle The myofibrils are composed of two kinds of filaments: thin filaments, consisting of two strands of actin and one strand of regulatory protein thick filaments, staggered arrays of myosin molecules the functional unit of the myofibril is a sarcomere ZOOLOGY Movement Muscle Actin and myosin are contractile proteins ZOOLOGY Movement Muscle Contraction Striated muscle contraction is explained by the sliding filament hypothesis Actin and myosin filaments become linked together by cross bridges (myosin heads), which act as levers to pull the filaments pass each other Z-lines pulled closer together, sarcomere shortens ZOOLOGY Movement Muscle Contraction muscles contract in response to nerve stimulation skeletal muscles are innervated by motor neurons whose cell bodies are in the spinal cord one motor neuron has many terminal branches that may innervate many muscle fibers a motor unit includes the motor neuron and all the fibers it innervates ZOOLOGY Movement The Neuromuscular Junction The place where a motor axon terminals on a muscle fiber is called the neuromuscular junctions Synaptic cleft is a small gap that separates the nerve fiber and muscle fiber Acetylcholine is stored in synaptic vesicles in the neuron ZOOLOGY Movement The Neuromuscular Junction When a nurse impulse arrives, acetylcholine is released into the cleft starting a wave of depolarization in the muscle fiber ZOOLOGY Movement Excitation-Contraction Coupling In the resting state, muscle shortening does not occur because thin tropomyosin strands on the actin myofilaments lie in a position that prevents the myosin heads from attaching to actin. ZOOLOGY Movement Excitation-Contraction Coupling When the muscle is stimulated, calcium ions are released that bind to troponin This causes a change in shape that causes the tropomyosin to move out of the way exposing binding sites on the actin molecule ZOOLOGY Movement Energy for Contraction Energy for muscle contraction comes from ATP ATP is synthesized during aerobic metabolism ZOOLOGY Movement Energy for Contraction During prolonged exercise, blood flow can't supply oxygen fast enough for aerobic metabolism to continue Anaerobic glycolysis is not as efficient, but still produces some ATP An oxygen debt builds up because the accumulated lactic acid must be oxidized ZOOLOGY Movement Fast and Slow Fibers Skeletal muscles consist of different types of fibers Slow oxidative fibers (red muscles) specialized for slow, sustained contractions Maintaining posture Fast glycolytic fibers (white muscles) lack an efficient blood supply and function anaerobically Running muscles in cats Fast oxidative fibers have an efficient blood supply and function aerobically for fast, sustained activities - Wing muscles in migratory birds ZOOLOGY ZOOLOGY