Summary

This document covers the Integumentary System, including its functions and parts. It details skin types, glands, derivatives, and vertebrate and invertebrate structures. This is part of a General Zoology course for 1st semester 2024.

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GENERAL ZOOLOGY DMD-1B | 1st Semester | 2024 PCZO101 SKIN GLANDS THE INTEGUMENTARY SYSTEM The Integumentary System acts as the protective I. Sweat Gland : Respond...

GENERAL ZOOLOGY DMD-1B | 1st Semester | 2024 PCZO101 SKIN GLANDS THE INTEGUMENTARY SYSTEM The Integumentary System acts as the protective I. Sweat Gland : Respond differently to heat barrier of our body. and nervous state, and respond to ★ “Integument” came from a Latin word that emotional and sensory stimuli ➔ Controls body temperature means “To cover” II. Sebaceous Glands : Found in the skin of ★ It includes accessory organs such as hair, mammals, these glands creates sebum feathers, scales, claws, hoofs etc. (oil) ★ Functions of Integumentary System: ★ Sebum lubricates the skin to ○ Helps to protect the body's tissues protect against friction and makes and organs. it more impervious to moisture. ○ Protects against infections and III. Ceruminous Glands : Involved in skin foreign invaders. problems ○ Hydrates the body IV. Mammary Glands : Organs that produce ○ Maintain a stable body milk temperature. (Homeostasis) Putting of blood vessel under fats to prevent getting cold Sweating to release heat ○ Transports and gets rid of waste materials. PARTS OF THE INTEGUMENTARY SYSTEM SKIN DERIVATIVES ★ Skin ★ Skin Appendages I. Nails : Protective plates over the fingertip ○ Hairs, Nails,Skin Glands and toes ★ Subcutaneous Tissue ➔ The area under your nail has many ○ The deepest skin layer that lies nerve endings, which allow you to closest to the muscle. receive more information about ○ Hypodermis objects you touch (sense of touch). SKIN II. Hoofs : A cylinder of horny material that surrounds and protect the tip of the toe The largest organ in the body. One of the main ➔ Found in ungulate mammals functions of the skin is protection. It protects the body from external factors such as bacteria, chemicals, and temperature. 1 GENERAL ZOOLOGY DMD-1B | 1st Semester | 2024 PCZO101 III. Horns and Antlers : Made an outer Chromatophores pigment bearing cells keratinized layer ➔ It is made of bone Serous Glands Poison glands (toxins) IV. Hair Structure : Consists of a shaft, which grows and rises above the skin surface. Mucous Glands Gas exchange and ➔ Located in the small fossa within produce watery the dermal thickness and is substances that make anchored into a hair follicle them slimy. Scales are rare in amphibians REPTILES : Class of vertebrates made up mostly of snakes, turtles, lizards, and crocodilians. ★ Dermis - Deeper layer of connective tissue with a rich supply of blood vessels and nerves. ★ Epidermis - Seven sub-layers of closely packed cells. ○ Thick, lack of glans, modified into VERTEBRATES INTEGUMENT keratinized cells. FISHES ★ Tetrapods ★ Fishes BONY FISH : The skin of bony fishes contains ★ Birds scales. TETRAPODS Highly keratinized cells and with a cornified layer as covering that forms the stratum corneum. AMPHIBIANS : Transitional between aquatic and terrestrial vertebrates. Types of Scales ★ Epidermis - Stratified epidermis with thin 1. CYCLOID SCALES - Concentric stratum corneum and very little keratin; ridges-milkfish Leydig cells. 2. CTENOID SCALES - w/spines or ctenii ★ Dermis - With chromatophores, poison 3. GANOID SCALES - rhomboid shape glands, and mucous glands. Composed of 4. COSMOID SCALES - extinct fishes dermal fibrous connective tissues. 5. PLACOID SCALES - spines directed caudally-sharks,skates 2 GENERAL ZOOLOGY DMD-1B | 1st Semester | 2024 PCZO101 CARTILAGINOUS : Skin is covered with horny teeth-like scales on the jaws that are modified to EPIDERMIS form teeth. (E.g SHARKS) FISHES Thin Placoid scales or dermal denticles 2 types of cell : ○ Epidermal cells Outer enamel; inner denting ○ Unicellular glands Epidermis does not cover scales Mucous cuticle on surface AMPHIBIANS Thin stratum corneum Very little keratin, leydig cell REPTILES Epidermal scales Thick outer layer of keratin JAWLESS FISH : Simplest of all fish and MAMMALS 5 layers of epidermis vertebrates. Includes lampreys and hagfish. ○ Corneum Creatures that have no jaws, mouth is ○ Lucidum ○ Ganosulum surrounded by a large round sucker. ○ Spinosum ○ Basale BIRDS BIRDS Thin and bilayered Comprises of : Integumentary system consists of the skin, the ○ Corneum feathers, and the appendages (claws and beak) ○ Basale which provide protection. DERMIS Two different tissues : FISHES Contains chromatophores Connective tissue of dermis and Organized into regular layers of fibrous hypodermis connective tissue. Cellular stratified epithelium of the dermis AMPHIBIANS Chromatophores, poison glands, and mucous glands INVERTEBRATES INTEGUMENT Fibrous connective tissues REPTILES With Chromatophores Consist of simple columnar cells, thin layer of May possess osteoderms connective tissue, and some possess cuticles that Fibrous connective tissues are highly variable structure. MAMMALS Well-vascularized and innervated Outer papillary layer Deeper reticular layer BIRDS Well-vascularized and innervated Richly supplied by blood vessels, sensory nerves, and smooth muscles. 3 GENERAL ZOOLOGY DMD-1B | 1st Semester | 2024 PCZO101 LAYERS OF EPIDERMIS THE HUMAN SKIN I. Stratum Corneum : The stratum corneum is the top layer of the epidermis. It prevents dehydration and renders defense against toxins and microbes Keratoncynites becomes Corneocytes, dead keratinocytes (protects you from harm) The corneocytes eventually shed as new keratinocyte cells develop in the stratum basale layer and move through the other layers of skin. II. Stratum Lucidum : A thin, transparent layer of keratinocytes that are becoming less round and have a flatter shape. Layer composed of dead skins Three General Layer of Human Skin Responsible for skin to stretch and be waterproof. III. Stratum Granulosum : Thin and not always 1. Epidermis - outermost layer; may contain present glands and is highly modified. Granular Layer ➔ Stratified squamous epithelium IV. Stratum Spinosum : Mostly consists of ➔ “Epi” = “Upon/Over” keratinocytes held together by sticky proteins ➔ Made of 5 layers called desmosomes. ➔ No blood vessels Helps make your skin flexible and 2. Dermis - Collagenous, reticular, and strong. elastic fibers V. Stratum Basale : The deepest layer of your ➔ “Core” of the integumentary epidermis. New skin cells develop in this layer. system It also contains the keratinocyte stem cells, ➔ “Derma” = “Skin” which produce the protein keratin. Contains melanocytes, responsible for ➔ Contains blood and lymph vessels, the production of melanin (pigment) and other structures (hair) ➔ Made of 2 layers of connective tissue. 3. Hypodermis - Adipose tissues and nerve endings are present here. ➔ “Subcutaneous layer” of the skin ➔ “Hypo” = “Below” ➔ Connect the skin to the underlying fascia (fibrous tissue) of the bones. ➔ Fat storage and provides insulation. 4 GENERAL ZOOLOGY DMD-1B | 1st Semester | 2024 PCZO101 THE SKELETAL SYSTEM Exoskeleton ○ Exo = outside ○ Hard, thick, outer covering made if The skeletal system is all the bony tissues in an protein and chitin animal’s body. It is a structural framework that ○ Sites for muscle attachment provides support and protection to the animal ○ Prevents internal issues from organs and body drying out E.g. : Arthropods such as beetles and crustaceans Functions of Skeletal System: Endoskeleton ★ Body shape and form ○ Endo = within ○ Rigid strong bones - bearing ○ Bones buried in soft tissue weight ○ For protection and support ○Cartilage - Firm yet flexible support within a certain structure Vertebrates - Animals with backbone and an (ex. Nose, external ears) internal skeleton called endoskeleton ★ Protects vital organs Composed of cartilage and bone ○ Ex. cranial bones (brain) ★ Body movements ○ Tendon - Muscle to bone Cartilage: Site for muscle attachment, attachment movement at joints, provide support, and ○Ligament - Bone to bone responsible for muscle contraction. attachment ➔ Cell - Chondrocytes ★ Storing minerals (calcium & phosphorus) Bone or Osseous Tissue : Provides a point of ○ Fats is stored in the internal attachment for muscle and transmits the force cavities of bones of muscular contraction from one part of the ★ Site for formation of blood cells body to another. ○ Bone marrow - gives rise to blood ➔ Reserves calcium and phosphate cells and platelets ➔ Manufactures RBC and some WBC Kinds of Skeleton: Invertebrates - Animals that do not have a Hydrostatic Skeletons backbone, instead they have soft inner bodies. ○ Fluid-filled internal body ○ Most common skeletal system Tetrapods - Four-limbed vertebrates, lift used for movement and support themselves to walk on land. ○ Common in invertebrates Their endoskeleton is modified for ○ Both circular and longitudinal support on land. muscle fibers ○ Shape is cylindrical E.g : Earthworm, Jellyfish, Starfish, and Anemone 5 GENERAL ZOOLOGY DMD-1B | 1st Semester | 2024 PCZO101 BONE TYPE SURFACE ANATOMY OF A BONE The 206 bones that compose the adult skeletons are divided into five categories based Projections that form joints on their shapes. Their shapes and their functions 1. Head are related such that each categorical shape of (i.e. Head of Femur) bone has a distinct function. 2. Condyle (i.e. Condyle of the femur) LONG Cylinder-like, longer than its 3. Facet wide (i.e. between atlas and the skull) Function: Leverage 4. Ramus E.g Femur, fibula, metatarsals, (i.e. Ramus of the mandible) humerus, ulna, radius, phalanges, metacarpals Projections that are the sites of muscle and SHORT Cube-like, equal length, width, ligament attachment and thickness 1). Tuberosity Function : Stability, support (i.e. Tibial tuberosity or ischial tuberosity-pelvis) E.g. Carpals, tarsals 2. Crest (i.e. Tibial crest) FLAT Thin and curved 3. Trochanter Function: Attachment for muscle and protectors of internal (i.e. Greater and lesser trochanter of the femur) organs 4. Line E.g. Sternum, ribs, cranial bones (i.e. Line of the femur) 5. Tubercle IRREGULAR Complex shape (i.e. Lesser & greater tubercle of the humerus) Function: Protects internal 6. Epicondyle organs (i.e. Lateral & medial epicondyle of the humerus and E.g. Vertebrae, facial bone femur) SESAMOID Small and round; embedded in 7. Spine tendons (i.e. Spinous process of the vertebrae) Functions: Protects tendons 8. Process E.g. Patallae (i.e. Transverse process of the vertebrae) GROSS STRUCTURE OF A LONG BONE Openings that allow blood vessels and nerves to pass 1. Meatus A long bone has two main regions: (i.e. External auditory meatus of the temporal bone) the diaphysis and the epiphysis. 2). Fissure The diaphysis is the hollow, (i.e. Superior and inferior tubular shaft that runs between orbital fissures) the proximal and distal ends of 3. Foramen the bone. Inside the diaphysis is (i.e. Foramen magnum) the medullary cavity, which is 4). Sinus filled with yellow bone marrow in (i.e. Frontal sinus) an adult. 6 GENERAL ZOOLOGY DMD-1B | 1st Semester | 2024 PCZO101 COMPACT AND SPONGY BONE DIVISION OF THE SKELETAL SYSTEM Compact bone is the denser, stronger of the two Two major division of the skeleton: types of bone tissue Found under the periosteum and in the AXIAL SKELETON VS APPENDICULAR SKELETON diaphyses of long bones Provides support and protection. AXIAL APPENDICULAR consists of the bones consisting of the of the head and trunk bones that support of a vertebrae the appendages Central axis of the Consists of skeleton appendages connected to the axial skeleton Composed of skull, Composed of ossicles of the ear, pectoral girdles, vertebral column, arms, foreams, hands, hyoid, rib cage and pelvis, legs, feet, and Spongy bone, also known as cancellous bone, sternum ankles contains osteocytes housed in lacunae Made up of 80 bones Made up of 126 bones Lacunae and osteocytes are found in a lattice-like network of matrix spikes Supports the upright Aid in the movement called trabeculae (singular = trabecula) position and protects of the body the internal organs AXIAL SKELETON The word axial is from the word axis, and refers to how the bones of the axial skeleton are located along the central axis of the body. Supports the organs in dorsal and ventral cavities 7 GENERAL ZOOLOGY DMD-1B | 1st Semester | 2024 PCZO101 A. SKULL : Protects the brain. Thoracic Cage : Consists of 85 openings and 22 Sternum - Breastbone, it is a long, flat, bones divided into cranial and and bony plate. facial bones ○ Protects the heart, lungs, and blood vessels Ribs - Long, curved bones that forms the rib cage ○ Humans have 24 ribs (pair) ○ True Ribs: 1-7 ○ False Ribs: 8-10 ○ Floating Ribs: (11-12) APPENDICULAR SKELETON Comprises 126 bones and is involved in locomotion and manipulation of objects in the environment. Two groups : Bones located within the limbs and the girdle bones that attach the limbs to the axial skeleton. Upper Extremities: The bones of the pectoral girdle consist of two bones (scapula and clavicle) and anchor the upper limb to the thoracic cage of the axial skeleton. Three regions of upper limb Arm (humerus) Forearm (ulna) B. VERTEBRAL COLUMN : The backbone or Hand spine. ○ Base of hands: 8 bones (carpal bones) Tall and thin organ located dorsally ○ Palm : 5 bones (metacarpal) ○ Fingers : 14 bones (phalanges) 33 Vertebrae in the human spine: ➔ Cervical (C1-C7) ◆ C1 Atlas ◆ C2 Axis ➔ Thoracic (T1-T12) ➔ Lumbar (L1-L5) ➔ Sacrum (S1-S5) ➔ Coccyx (4) 8 GENERAL ZOOLOGY DMD-1B | 1st Semester | 2024 PCZO101 OSTEOLOGY Lower Extremities: The pelvic girdle is formed by a single bone, the hip or coxal bone, and serves as the attachment point for each lower limb. Each Osteology - study of bone structure and hip bone is joined to the axial skeleton by its treatment of bone disorder attachment to the sacrum of the vertebral column. The right and left hip bones attach to each other Bone Ossification (Osteogenesis) - formation of anteriorly. bones by osteoblast Intramembranous Ossification : flat Lower limb contains 30 bones divided into 3 bones (skull) regions: Thigh Endochondral Ossification : All the bones Leg Foot INTRAMEMBRANOUS OSSIFICATION ○ Femur : simple bone of thigh ○ Patella : kneecap 1. An ossification center appears in the ○ Tibia : Medial side fibrous connective tissue membrane ○ Fibula : thin bones of the lateral leg Selected centrally located mesenchymal cells cluster and Bones of the foot: Tarsal, Metatarsal, and differentiate into osteoblasts phalanges 2. Bone matrix (osteoid) is secreted within the fibrous membrane Osteoblasts begin to secrete osteoid Trapped osteoblasts become osteocytes 9 GENERAL ZOOLOGY DMD-1B | 1st Semester | 2024 PCZO101 3. Woven bone and periosteum form BONE GROWTH Accumulating osteoid is laid down between embryonic blood vessels, Appositional Growth : Formation of new bone on which forms a random network of the surface of existing bone trabeculae. Occurs when osteoblast deposit a new bone matrix between the periosteum and the existing bone matrix The increase in width of long bones Endochondral Growth : Growth of cartilage in the epiphyseal plate and its eventual replacement by 4. Bone collar of compact bone forms and bone red marrow appears The increase in length of the bones Trabeculae just deep to the periosteum thicken, forming a BONE REMODELING woven bone collar that is later replaced with mature lamellar The removal of old bone by cells called bone osteoclast and the deposition of new bone by Spongy bone consisting of distinct osteoblast trabeculae, persist internally and Occurs in all bone its vascular tissue becomes red Remodeling is responsible for: marrow 1. Bone growth 2. Changes in bone shape 3. Adjustment of bone to stress 4. Bone repair 5. Calcium ion regulation Three consecutive phases of bone remodeling: 1. Resorption - Digestion of old bones ENDOCHONDRAL OSSIFICATION 2. Reversal - Mononuclear cells appear on the bone surface 3. Formation - Osteoblasts lay down new bone until the resorbed bone is co mpletely replaced. 10 GENERAL ZOOLOGY DMD-1B | 1st Semester | 2024 PCZO101 THE MUSCULAR SYSTEM BONE REPAIRING A process in which a bone repairs itself following SMOOTH MUSCLE a bone fracture. Spindle-shaped, nonstriated When a bone is broken: Involuntary muscle A clot forms in the damage area Found in the walls of internal organs Callus forms (zone of tissue repair) CARDIAC MUSCLE Osteoblast enter the callus and form Striated, branched, and it contracts cancellous bone Found only in the heart Cancellous bone is slowly remolded to Involuntary muscle form compact and repair is complete SKELETAL MUSCLE Striated muscle (lines) Has synergy Multinucleated fibers Voluntary muscle PARTS OF MUSCLE BONE AND CALCIUM HOMEOSTASIS Bone serves as the major storage site for calcium. Movement of calcium helps determine blood calcium level. Calcium moves into bone as osteoblast build new one Calcium move out of bone as osteoclasts break down bone Calcium Homeostasis is maintained by parathyroid hormone and calcitonin 1. ENDOMYSIUM - Wraps the muscle fiber (cell) 2. PERIMYSIUM - Wraps the fascicle (bundle of muscle fiber) 3. EPIMYSIUM - Wraps the whole muscle 11 GENERAL ZOOLOGY DMD-1B | 1st Semester | 2024 PCZO101 TYPES OF BODY MOVEMENTS NEUROMUSCULAR JUNCTION The neuromuscular junction (NMJ) is a synaptic connection between the terminal end of a motor nerve and a muscle (skeletal/ smooth/ cardiac). It is the site for the transmission of action potential from nerve to the muscle. An essential synapse for muscle contraction and movement. ATP MOLECULE: 12 GENERAL ZOOLOGY DMD-1B | 1st Semester | 2024 PCZO101 SLIDING FILAMENT THEORY THE CIRCULATORY SYSTEM Hematopoiesis Heart Blood Circulation ECG Blood Vessels Immunology HEMATOPOIESIS The process of blood cell production and development Occurs in the Bone Marrow Myeloid Cells - Give rise to various cells, including red blood cells, platelets, granulocytes (neutrophils, eosinophils, basophils), monocytes, and dendritic cells Lymphoid Cells - Produce lymphocytes, including B cells, T cells, and natural killer (NK) cells. RED BLOOD CELL 120 days life span Hemoglobin molecule 13 GENERAL ZOOLOGY DMD-1B | 1st Semester | 2024 PCZO101 2 PHASES Hematocrit - The percentage by volume of red cells in your blood. 1. Primary Hemostasis : Formation of A type of blood testing platelets A centrifuge machine is utilized to conduct 2. Secondary Hemostasis : Clotting factors, the testing protein and protein factors Responsible for producing fibrin mesh ( traps red blood cells and platelets and eventually forms a stable blood clot.) Missed protein = blood clotting HEART ANATOMY LOW RBC = LOW HEMATOCRIT ANEMIA HIGH RBC = HIGH HEMATOCRIT POLYCYTHEMIA Fluid formed elements: RBC ERYTHROCYTE WBC LEUKOCYTE RED VEINS - carries oxygenated blood BLUE VEINS - carries deoxygenated blood PLATELETS THROMBOCYTE Veins and Arteries: Base of the heart Lower part: Apex of the heart HEMOSTASIS Position of the heart: 4th to 5th intercostal space of the ribs Blood clotting 14 GENERAL ZOOLOGY DMD-1B | 1st Semester | 2024 PCZO101 HEART ANATOMY DEXTROCARDIA : A condition in which the heart is located at the right side. 2 TYPES OF CIRCULATION 1. Pulmonary - Distribution of deoxygenated blood to lungs and returns oxygenated to Blood circulation: back to the heart 1. Superior and Inferior Vena Cava 2. Systemic - Distribution of oxygenated 2. Right atrium blood to different parts of the body 3. Tricuspid valve 4. Right ventricle 4 CHAMBERS OF HEART 5. pulmonary semilunar valve 6. Pulmonary trunk 7. pulmonary arteries 8. Lungs 9. pulmonary veins 10. Left atrium 11. bicuspid valve 12. Left ventricle 13. Aortic semilunar valve 14. Body 15 GENERAL ZOOLOGY DMD-1B | 1st Semester | 2024 PCZO101 CONDUCTION BLOOD VESSEL ANATOMY The network of nodes, cells and signals that controls your heartbeat. SA NODE : Generates an electrical signal that causes the upper heart chambers (atria) to contract The pacemaker AV NODE :. The signal then passes through the Arteries has thicker muscle walls than Ventricles AV (atrioventricular) node to the lower heart chambers (ventricles) ELECTROCARDIOGRAM (ECG) An electrocardiogram (ECG or EKG) is a quick test to check the heartbeat. It records the electrical signals in the heart. P WAVE : Atrial depolarization (contraction) QRS WAVE : Ventricular depolarization (contraction) T WAVE : Ventricular repolarization (relaxation) Pacemaker : a small, battery-powered device that prevents the heart from beating too slowly. 16

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