Bio. Sci. 1 Hand-outs 2 PDF

Bio. Sci. – 1 q LOCATION “Biological Science” - Stomach, intestines, glands, some ducts, FINAL HAND-OUTS bronchioles of lungs, auditory tubes, uterus, and Prepared by:...

Bio. Sci. – 1 q LOCATION “Biological Science” - Stomach, intestines, glands, some ducts, FINAL HAND-OUTS bronchioles of lungs, auditory tubes, uterus, and Prepared by: uterine tube. EXUR M. BUENAFLOR d. Stratified squamous epithelium I. Animal Morphology and Physiology q STRUCTURE Tissue – a tissue consists of a group of closely - Many layers of cells in which the basal layer is associated, similar cells that carry out specific cuboidal and becomes flattened at the free surface. functions. q FUNCTION Types of tissues: - Protection against abrasion and infection. q Epithelial Tissue q LOCATION q Connective Tissue - Skin, mouth, throat, esophagus, anus, vagina, and q Muscular Tissue cornea. q Nervous Tissue e. Pseudo stratified epithelium 1. Epithelial Tissue forms the covering or lining of q STRUCTURE free body surfaces, both internal and external. - Single layer of cells; some are tall and thin. - Example: outer layer of the skin is formed from - The nuclei & at different levels appears stratified. epithelial tissue as are the inner lining of the q FUNCTION digestive tract and blood vessels. - Movement of mucus (or fluid) that contains Functions: Protection, absorption, excretion, foreign particles. secretion, and lubrication. q LOCATION - does not have blood vessels - Nasal cavity, nasal sinuses, auditory tubes, so, gases and nutrients that reach the epithelium pharynx, larynx, trachea, and bronchi of lungs. must diffuse across the basement membrane from f. Transitional epithelium underlying tissues. q STRUCTURE Types Epithelial Tissue: - Stratified cells that appear cube-like when the a. Simple squamous epithelium organ or tube is relaxed and appear squamous q STRUCTURE when the organ or tube is distended by fluid. - single layer of thin flat cells. q FUNCTION q FUNCTION - Accommodation by fluid fluctuation in an organ or - Diffusion, filtration, and protection against tube; protection against the caustic effects of urine. friction. q LOCATION q LOCATION - Urinary bladder, ureters, and superior urethra. - Lining of blood vessels, heart, lymph vessels, and 2. Connective Tissue: cells surrounded by large serous membranes, alveoli (airsacs) of lungs, and amounts extracellular material. kidney tubules (Bowman's capsule). Functions: b. Simple cuboidal epithelium - Hold other tissues together. q STRUCTURE - Provide supporting framework of the body. - Single layer of cubed shape cells; some cells have - Transport substances. ex. BLOOD microvilli (kidney tubules) or cilia (terminal Types of Connective Tissue: bronchioles of lungs). a. Dense connective tissue q FUNCTION q STRUCTURE - Secretion and absorption by cells of kidney - Matrix consist entirely of collagen fibers produced tubules. by fibroblast. The fibers can all be oriented in the - Movement of mucus-containing particles out of same direction (tendons and ligaments), or in many the terminal bronchioles by ciliated cells. different directions (dermis and capsules). q LOCATION q FUNCTION - Kidney tubules, glands & their ducts, choroid - Able to withstand great pulling forces in the plexus of the brain, terminal bronchioles of lungs, direction of fiber orientation. and surface of ovaries and retina. q LOCATION c. Simple columnar epithelium - Tendons (attached muscle to bones) q STRUCTURE - ligaments (attached bone to bones) - Single layer of tall, narrow cells; some have - dermis of skin, and organ capsule. microvilli and cilia. b. Loose or areolar Connective Tissue q FUNCTION q STRUCTURE - Secretion by cells of stomach, intestines, and - Cells (fibroblast, macrophages, and lymphocytes) glands. within a fine network of mostly collagen fibers; the - Absorption by cells of intestine. cells and fibers are separated from each other by - Movement of mucus by ciliated cells that clear the fluid-filled spaces. lungs; movement of egg through the uterine tubes.  q FUNCTION q FUNCTION - Loose packing, support, and nourishment for the - Confers elasticity structures with which it is associated. q LOCATION q LOCATION - Framework of liver; lymph nodes; spleen - Widely distributed throughout the body, it is the h. Reticular Connective Tissue substance on which most epithelial tissue rests. It is q STRUCTURE the packing between glands, muscles, nerves and - Consists of interlacing reticular fibers attaches the skin (dermis) to underlying tissues. q FUNCTION c. Adipose tissue - Support q STRUCTURE q LOCATION - Little extracellular material between adipose cells; - Structures that must both expand and return to the cells are so full of lipids and the cytoplasm is their original size, such as lung tissue and large pushed to the periphery of the cell. arteries q FUNCTION 3. The Muscular Tissue: - Energy storage, packing material that provides - the ability to contract or shorten, making protection, and heat insulator. movements possible. q LOCATION Types Muscular Tissue: - Under skin, around organs such as the heart and q Cardiac Muscle kidneys, in the breast, and in bones. q Skeletal Muscle d. Cartilage q Smooth Muscle q STRUCTURE a. Cardiac Muscle - Solid matrix with fibers dispersed throughout the q STRUCTURE ground substance. - Cylindrical in shaped and straited, and have a - Chondrocytes are found within lacunae. single nucleus. q FUNCTION - The cells are branched and are connected to other - Hyaline cartilage forms a smooth surface joints, a by intercalated disk. site of bone growth, and embryonic skeleton. q FUNCTION Fibrocartilage can withstand great pressure, and - Responsible for pumping of blood. elastic cartilage returns to original shape when q LOCATION bent. - Muscle of the heart q LOCATION b. Skeletal Muscle - Hyaline cartilage found in ribs, respiratory tract, q STRUCTURE end of bones, embryonic skeleton. - Are cylindrical in shape, striated, and - Fibrocartilage found in intervertebral disks, multinucleated. symphysis pubis and articular disk of knees. - Attaches to bone and normally thought as a - Elastic cartilage found in external ear. "muscle". e. Bone tissue - It is the meat of an animals comprises 40 % of q STRUCTURE person's body weight. - Hard, mineralized matrix with osteocytes located q FUNCTION within lacunae. - Body movements (voluntary control). q FUNCTION q LOCATION - Provides great strength and support and protects - between skin and bones. internal organs such as the brain. c. Smooth Muscle q LOCATION q STRUCTURE - Bones - Tapered at each end, not straited, and have a f. Blood single nucleus. q STRUCTURE q FUNCTION - Blood cells with in fluid matrix called plasma. - Responsible for pumping of blood under q FUNCTION involuntary control. - Transport oxygen, carbon dioxide, hormones, - Movement of food through digestive tract. nutrients, waste products, and other substances. - Emptying the urinary bladder. - Protects the body from infection and is involved in q LOCATION temperature regulation. - Muscle of the heart, skin, eyes. q LOCATION 4. Nervous Tissue: - Within the blood vessels and the heart - Forms the brain, spinal cord, and nerves. g. Elastic Connective Tissue Functions: q STRUCTURE - Responsible for coordinating and controlling many - Branching elastic fibers interspersed with of the body's activities. fibroblasts ex. conscious control of skeletal muscles and unconscious regulation of cardiac muscle. - Awareness to external environment, emotions, Skin - technically refers to the vertebrate reasoning skills, and memory. integument. It has the same basic structure in all ex. action potential- communication of nervous vertebrates including fish, reptiles, birds, humans tissue to each other by electrical signals. and other mammals. q NEURONS or nerve cell. Skin layers: - Responsible for action potential conduction and 1. Epidermis - outermost layer of the skin support cells. composed of squamous cells. This is the top layer of - 3 parts: (dentrites, cell body, axon) skin made up of epithelial cells. It does not contain q NEUROGLIA blood vessels. - support cells of the nervous system. Its main function is protection, absorption of - function to nourish, protect (surround the axon), nutrients, and homeostasis. In structure, it consists and insulate neurons. of a keratinized stratified squamous epithelium Parts of Neurons comprising; q Dendrite Four types of cells: - are nerve cell processes (extensions). a. keratinocytes - received action potential and conduct them b. melanocytes toward the cell body. c. Merkel cells q Cell body d. Langerhans' cells. - contains nucleus and is the site of general cell The major cell of the epidermis is the keratinocyte, functions. which produces keratin. Keratin is a fibrous protein q Axon that aids in protection. Keratin is also a water- - are nerve cell processes (extensions). proofing protein. Millions of dead keratinocytes rub - usually conducts action potentials away from cell off daily. The majority of the skin on the body is body. keratinized, meaning waterproofed. The only skin - only 1 per neuron is present. on the body that is non-keratinized is the lining of skin on the inside of the mouth. Non-keratinized II. Organs and Organ systems cells allow water to "stay" atop the structure. Organs and Organs System The protein keratin stiffens epidermal tissue to - The human body is made up of several organ form fingernails. Nails grow from thin area called systems that all work together as a unit to make the nail matrix; growth of nails is 1 mm per week on sure the body keeps functioning. There are ten average. The lunula is the crescent-shape area at major organ systems in the body, each of which the base of the nail, this is a lighter color as it mixes plays a different role in helping the body work. with the matrix cells. I. Integumentary system is the outer covering of Layers of epidermis the body. The protective wrapping that includes the 1. Stratum basal skin and its appendages (including hair, scales, 2. Stratum spinosum feathers, hooves, and nails). it serve to waterproof, 3. Stratum granulosum cushion, and protect the deeper tissues, excrete 4. Stratum lucidum wastes, and regulate temperature and is the 5. Stratum corneum attachment site for sensory receptors to detect Dermis –The dermis is the middle layer of skin, pain, sensation, pressure, and temperature. composed of dense irregular connective tissue and Functions: areolar connective tissue such as collagen with The integumentary system has multiple roles in elastin arranged in a diffusely bundled and woven homeostasis. All body systems work in an pattern. interconnected manner to maintain the internal The dermis has two layers. One is the papillary conditions essential to the function of the body. - layer which is the superficial layer and consists of The skin has an important job of protecting the the areolar connective tissue. The other is the body and acts as the body against sunburns by reticular layer which is the deep layer of the dermis secreting melanin. and consists of the dense irregular connective - Generate vitamin D through exposure to tissue. These layers serve to give elasticity to the ultraviolet light. integument, allowing stretching and conferring - Store water, fat, glucose, and vitamin D. flexibility, while also resisting distortions, wrinkling, - Maintenance of the body form. Formation of new and sagging. The dermal layer provides a site for the cells from stratum germinativum to repair minor endings of blood vessels and nerves. Many injuries chromatophores are also stored in this layer, as are Invertebrate integument: the bases of integumental structures such as hair, A. Unicellular Organisms – the plasma membrane feathers, and glands. serves as their outer covering - contains the blood vessels, nerves glands and B. Multicellular Organisms – the epidermis serves auxiliaries as their principal outer covering. Hypodermis (Subcutis) – is the innermost and Protective Coloration: thickest layer of the skin. It invaginates into the Camouflage –a process in which the animals dermis and is attached to the latter, immediately resemble the background against where they live. above it, by collagen and elastin fibres. It is Mimicry - a process in which some animals essentially composed of a type of cells specialised in resemble other animals or related species accumulating and storing fats, known as adipocytes. Countershading – a process in which the surfaces These cells are grouped together in lobules of the animal that are habitually turned toward the separated by connective tissue. light are dark those on the inside are pale. This commonly observed in fishes. II. Skeletal system - forms the framework of the body. The human skeleton contains 206 bones, 6 of which are the tiny bones of the middles ear (3 in each ear) that function in hearing. - includes all of the bones and joints in the body. Each bone is a complex living organ that is made up of many cells, protein fibers, and minerals. - The skeleton acts as a scaffold by providing support and protection for the soft tissues that make up the rest of the body. Parts of skeletal system Bones - all bones are made up of 2 types of tissue : Integumentary glands compact or dense tissue and spongy tissue. 1. Sweat glands –simple,tubular highly coiled glands There are 4 types of bones : that occur over much of the body in most 1. Long bones (like those in the arms and legs) mammals. Its function is to regulates temperature 2. Short bones (like those found in the ankles and 2. Scent glands – present nearly in all mammal wrists) which are used in communication with members of 3. Flat bones (like ribs and those in the skull) the same species to mark territorial boundaries for 4. Irregular bones (like those vertebrae in the spine) warming or for defense. 5. Bone marrow - The soft, sponge-like tissue in 3. Sebaceous glands - intimately associated with the center of most bones. It produces white blood hair follicles, albeit, some are free and open cells, red blood cells, and platelets. It is either directly onto the surface yellow or red. Red marrow is primarily found in flat In humans, these are numerous in the bones. Yellow marrow is primarily made of fatty scalp and on the surface bone cells and is found in long bones 3. Mammary glands – occurs in all females and in 6. Ligaments - are bands of tough, fibrous material rudimentary form in males that are used to connect bones to create joints - Secrets milk which nourish the young 7. Tendons - are similar in structure to ligaments Animal coloration but are used to connect muscles to bones. 4. Biochromes – integumentary pigments 8. Joints - are formed at any joint where two bones responsible for most integumentary colors. These connect. are encapsulated in large cells with branching 9. Cartilage- a form of fibrous connective tissue that process called chromatophores is composed of closely packed collagenous fibers in Type of chromatophores : a rubbery gelatinous substance called chondrin. It a. Melanophores – contains the black or pigment provides flexible support for certain structures in melanin adult humans including the nose, trachea, and ears. b. Xantophores – contains the yellow, orange and Functions of the skeleton red color collectively called carotenoids 1. Support - it supports the softer tissues and c. Ommochromes and pteridines are yellow provides points of attachment for most skeletal pigments present in mollusc and reptiles. muscles. d. Iridophores – contains crystals of guanine or 2. Protection - provides mechanical for many of the some purine, rather than pigments. It produce body’s internal organs, reducing risk of injury to silvery, metallic effect by reflecting light. them. Structural colors – produced by the physical 3. Assisting in movement - when associated structure of the surface tissue which reflects certain muscles contract they cause bones to move lights wavelengths and eliminates other. 4. Mineral storage - bone tissues store several -responsible for the beautifully minerals including calcium (Ca) and phosphorus (P) iridescent and metallic hues found in animal when required, bone releases mineral into blood kingdom ,facilitating the balance of mineral in the body 5. Production of blood cells - bone marrow inside the larger bones produce RBC  6. Chemical energy storage - yellow bone marrow consist mainly of adipose cells. It is an important chemical energy reserve. Bones are arranged into 2 major divisions : 1. Axial Skeleton - runs along midline axis and is made up of 80 bones in the following regions: a. Skull b. Hyoid c. Auditory ossicles d. Ribs e. Sternum f. Vertebral column 2. Appendicular Skeleton – is made up of 126 bones in the following regions: a. Upper limbs b. Lower limbs c. Pelvic girdle d. Pectoral girdle Skull - is a bony structure, part of the skeleton, that is in the human head and which supports the - structures of the face and forms a cavity for the Auditory ossicles – the smallest bones in the brain. body,these are the malleus,incus,and stapes. Found - is composed of 22 bones that are fused together in the small cavity inside of the temporal bone,they except for the mandible. These 21 fused bones are transmit and amplify sound from eardrum to the separate in children to allow the skull and brain to inner ear grow, but fuse to give added strength and Sternum – the breastbone is a thin, knife shaped protection as an adult. The mandible remains as a bone located along the midline of the interior side movable jaw bone and forms the only movable of the thoracic region of the skeleton – it connects joint in the skull with the temporal bone. the ribs by thin bands of cartilage called the costal - is composed of two parts: the cranium and the cartilage. mandible. Pectoral girdle – connects the upper limb bones to Mandible – lower jaw or jawbone is a bone forming the axial skeleton and consist of the left and right the skull with the cranium. calricles and left and right scapulae. Cranium - portion of the skull enclosing the brain to Humerus – is the bone of the shoulder with the protect brain damage; the braincase scapula and forms the elbow joint with the lower Hyoid - is the only bone in the body that does not arm bone the form a joint with any other bone. It is floating bone The two bones of the forearm: the function of it is to help hold the trachea open Radius – The long bone in the forearm, on the side and to form a long connection for the tongue of the thumb. muscles. Ulna – is on the medial side of the the forearm and forms a hinge joint with the humerus at the elbow. Lower arm – bones form the wrist joint with the carpals Carpals or wrist bones – are the short bones which form the wrist. There are 8 carpals in each wrist, which have ligaments attached to allow for a gliding movement. It is connected to the five metacarpals that form bones of the hand and connect to each of the fingers. Each of the finger has a bones known as 3 phalanges except for the thumb which only has 2 phalanges. The eight carpals are: a. Pisiform b. Triquetrum (also called Triangular) c. Hamate d. Capitate e. Scaphoid f. Trapezium g. Trapezoid h. Lunate Pelvic girdle - connects the lower limb to the axial Hyoid and Auditory Ossicles skeleton The hyoid is a small, U-shaped bone found just Femur – is the largest bone in the body and the inferior to the mandible. The hyoid is the only bone only bone of the thigh(femoral) region. It forms in the body that does not form a joint with any the ball and socket hip joins with the hip bone and other bone—it is a floating bone. The hyoid’s forms the knee joint with the ibia and patella function is to help hold the trachea open and to commonly called the kneecap. form a bony connection for the tongue muscles. Patella – is one of the few bones that are not Vertebrae present at birth, forms in early childhood to support Twenty-six vertebrae form the vertebral column of knee for walking and crawling. the human body. They are named by region: Bones in the lower leg form with the ankle joint a. Cervical (neck) - 7 vertebrae with the talus : b. Thoracic (chest) - 12 vertebrae Tibia – is much longer than fibula and bears almost c. Lumbar (lower back) - 5 vertebrae all of the body’s weight d. Sacrum- 1 vertebra Fibula – is mainly a muscle attachment point and is e. Coccyx (tailbone) - 1 vertebra used to help maintain the balance Ribs and Sternum Talus – one of the 7 tarsals bones in the foot. The sternum, or breastbone, is a thin, knife-shaped Tarsals – are a group of 7 small bones that form the bone located along the midline of the anterior side posterior end of the foot and the heel. It forms of the thoracic region of the skeleton. The sternum joints with the five long metatarsals of the foot then connects to the ribs by thin bands of cartilage called each of the phalanges in the toes. the costal cartilage. Pectoral Girdle and Upper Limb - connects the upper limb (arm) bones to the axial skeleton and consists of the left and right clavicles and left and right scapulae. Pelvic Girdle and Lower Limb Formed by the left and right hip bones, the pelvic girdle connects the lower limb (leg) bones to the axial skeleton. Types of Bones: 1. Long Bones - Long bones are longer than they are wide and are the major bones of the limbs. Long bones grow more than the other classes of bone throughout childhood and so are responsible for the bulk of our height as adults. 2. Short Bones - Short bones are about as long as they are wide and are often cubed or round in shape. The carpal bones of the wrist and the tarsal bones of the foot are examples of short bones. 3. Flat - flat bones vary greatly in size and shape, but have the common feature of being very thin in one direction. Because they are thin, flat bones do not have a medullary cavity like the long bones. The frontal, parietal, and occipital bones of the cranium—along with the ribs and hip bones—are all examples of flat bones. 4. Irregular - Irregular bones have a shape that does not fit the pattern of the long, short, or flat bones. The vertebrae, sacrum, and coccyx of the spine—as well as the sphenoid, ethmoid, and zygomatic bones of the skull—are all irregular bones. 5. Sesamoid - The sesamoid bones are formed after birth inside of tendons that run across joints. Sesamoid bones grow to protect the tendon from stresses and strains at the joint and can help to give a mechanical advantage to muscles pulling on the tendon Skeletal System Physiology forms the musculoskeletal system, which is Support and Protection responsible for movement of the human body. The skeletal system’s primary function is to form a It permits movement of the body, maintains solid framework that supports and protects the posture and circulates blood throughout the body's organs and anchors the skeletal muscles. The nervous system , although some muscles (such as bones of the axial skeleton act as a hard shell to the cardiac muscle) can be completely autonomous. protect the internal organs—such as the brain and Muscles - Provides strength, balance, posture, the heart—from damage caused by external forces. movement and heat for the body to keep warm. The bones of the appendicular skeleton provide Anatomy - there are approximately 639 skeletal support and flexibility at the joints and anchor the muscles in the human body. muscles that move the limbs. Kinds of animal movement: Movement 1. Amoeboid movement - a crawling –like type of The bones of the skeletal system act as attachment movement accomplished by protrusion of points for the skeletal muscles of the body. Almost cytoplasm of the cell involving the formation of every skeletal muscle works by pulling two or more pseudopodia bones either closer together or further apart. Joints -is a form of movement especially of amoebas and act as pivot points for the movement of the bones. other unicellular forms. It is also found in many The regions of each bone where muscles attach to wandering cells of higher animals such as white the bone grow larger and stronger to support the cells,embryonic mesenchyme and numerous other additional force of the muscle. In addition, the mobile cells that move through the tissue spaces overall mass and thickness of a bone increase when 2. Ciliary movement –is done by locomotory it is under a lot of stress from lifting weights or structures, the cilia and flagella,characteristics to supporting body weight. the ciliates and flagellates respectively. Hematopoiesis Cilia - are minute hairlike processes that extends Red bone marrow produces red and white blood from the surfaces of the cell of many animals cells in a process known as hematopoiesis. Red (paramecium caudatum) bone marrow is found in the hollow space inside of Flagella – whip like structure usually present single bones known as the medullary cavity. Children tend or in small number at one end of a cell ( e.g to have more red bone marrow compared to their Eugenia, sperm cell and sponges) body size than adults do, due to their body’s 3. Muscular movement - a formed of animal constant growth and development. The amount of movement performed by the muscular tissues (cells red bone marrow drops off at the end of puberty, of which are specialized for contractility). replaced by yellow bone marrow. Storage The Three Distinct Types of Muscles: The skeletal system stores many different types of 1. Visceral Muscle - is found inside of organs like essential substances to facilitate growth and repair the stomach, intestines, and blood vessels. The of the body. The skeletal system’s cell matrix acts as weakest of all muscle tissues, visceral muscle makes our calcium bank by storing and releasing calcium organs contract to move substances through the ions into the blood as needed. Proper levels of organ. calcium ions in the blood are essential to the proper function of the nervous and muscular systems. Growth and Development The skeleton begins to form early in fetal development as a flexible skeleton made of hyaline cartilage and dense irregular fibrous connective tissue. These tissues act as a soft, growing framework and placeholder for the bony skeleton that will replace them. As development progresses, blood vessels begin to grow into the soft fetal skeleton, bringing stem cells and nutrients for bone growth. III. Muscular System - is an organ system consisting of skeletal, smooth and cardiac muscles. It permits movement of the body, maintains posture, and circulates blood throughout the body. The muscular system in vertebrates is controlled through visceral muscle is controlled by the unconscious the nervous system, although some muscles (such part of the brain, it is known as involuntary as the cardiac muscle can be completely muscle—it cannot be directly controlled by the autonomous. Together with the skeletal system it conscious mind. The term “smooth muscle” is often used to describe visceral muscle because it has a heart is made of cardiac muscle tissue that very smooth, uniform appearance when viewed stimulates other cardiac muscle cells to contract under a microscope. Stimulation of Contraction 2. Skeletal Muscle - is the only voluntary muscle - Muscles contracts in response to nerve tissue in the human body—it is controlled stimulation consciously. Every physical action that a person - If the nerve supply to the muscle is severed, the consciously performs (e.g. speaking, walking, or muscle atrophies or wastes away writing) requires skeletal muscle. Energy for Contraction - ATP – is the immediate source of energy for the muscular contraction - Creatine phosphate- a source of energy for muscular that contains even more free bond energy than ATP - Glycogen – the major source of carbohydrates inmuscle. This is also a source of energy for muscular contraction because this compound could be readily converted into gluscose-6- phosphate(the starting material for cellular respiration that ultimately leads to the generation of ATP). Phases of contraction a. Latent period – interval between the initial stimulus and shortening. - No mechanical change that occurs within the muscle but there is liberation of energy required for Skeletal muscle is to contract to move parts of the contraction body closer to the bone that the muscle is attached b. Contraction period - the time from the to. Most skeletal muscles are attached to two bones beginning of mechanical response to its peak across a joint, so the muscle serves to move parts of - Relaxation period- the time from the peak of those bones closer to each other. contraction to return to original length. 3. Cardiac Muscle - found only in the heart, cardiac c. Tetanus – single sustained muscular contraction muscle is responsible for pumping blood because of the extreme rapidity in the application throughout the body. Cardiac muscle tissue cannot of successive stimuli, in here, the muscle cannot be controlled consciously, so it is an involuntary relax between successive stimuli muscle. d. Tonus – partial contraction of the muscles e. Muscles fatigue - results when there is accumulation of lactic acid due to the depletion of stored energy or insufficiency of oxygen leading to the conversion of glycolytic product, pyruvic acid, into lactic acid. IV. Digestive System - is a group of organs working together to convert food into energy and basic nutrients to feed the entire body. - its function is digestion and absorption. Digestion is the breakdown of food into small molecules, which are then absorbed into the body. The function of the digestive system is to change complex organic nutrient molecules into simple organic and inorganic molecules that can then be absorbed into the blood or lymph to be transported to cells. Types of Digestion The Mechanical digestion: is the physical breaking up of food into smaller pieces. Chewing is an example of this. As food is broken up, more of its surface area is exposed for the action of digestive While hormones and signals from the brain adjust enzymes. the rate of contraction, cardiac muscle stimulates The chemical digestion: is the work of digestive itself to contract. The natural pacemaker of the enzymes, in which complex chemical molecules are changed into much simpler chemicals that the body can utilize. Such enzymes are specific with respect muscles are found in each side of the mouth. They to the fat, protein, or carbohydrate food molecules help move the lower jaw and give it a biting force. each can digest. - Mastication (chewing) of food For e.g., protein-digesting enzymes work only on - Mixing masticated food with saliva proteins, not on carbohydrates or fats. - Initiation of swallowing by the tongue End Products of Digestion - Allowing for the sense of taste Each of these complex molecules is digested to a 2. Pharynx - Serves as a passageway for air and food much more simple substance that the body can - Food is propelled to the esophagus. then use. - Food movement is by alternating Carbohydrates: such as starches and disaccharides, contractions of the muscle layers (peristalsis) are digested to monosaccharides such as glucose, 3. Esophagus - From the mouth, food goes down fructose, and galactose. the esophagus through the pharynx or throat. The Proteins: are digested to amino acids. esophagus is a muscular tube that can open and Fats: are digested to fatty acids and glycerol. close at the pharynx. Also part of food, and released during digestion, are - Runs from pharynx to stomach through the vitamins, minerals, and water. diaphragm Digestive Processes - Conducts food by peristalsis (slow rhythmic 1. Ingestion - brining food into the mouth (eating) squeezing) 2. Propulsion - moving food through the GI tract, - Passageway for food only (respiratory system peristalsis (contractions of smooth muscle in GI branches off after the pharynx) tract) helps to move the food along. It can also open and close to the stomach. The walls 3. Mechanical digestion- physical change of the of the esophagus consist of smooth muscles. The food particles from large to small, this helps to wavelike movement of these muscles, increase the surface area to make chemical called peristalsis, pushes the food down to the digestion more effective. Actions include chewing, stomach. churning of food in stomach, and mixing food with 4. Stomach - is a hollow muscular organ shaped like digestive juices. a bag. Its upper end is connected to the esophagus 4. Chemical digestion- chemical change of the food while the lower end is connected to the small particles, bonds are broken to change a large intestine. molecule into a smaller one so absorption can - Acts as a storage tank for food happen more effectively. This involves the use of - Site of food breakdown enzymes, hydrochloric acid, and other digestive - Chemical breakdown of protein begins juices. - Delivers chyme (processed food) to the small 5. Absorption- transport of digested food molecules intestine from the GI into the blood and lymphatic vessels The stomach is flexible and can expand when you 6. Defecation - elimination of feces (indigestible eat. It can hold from 1 to 3 liters of food. The substance/digestive waste) stomach acts as a storage bag of food. Two divisions of the digestive system 5. Intestines - Are found below the stomach and a. The alimentary tube: extends from the mouth to liver. the anus. They form the major part of the digestive tract. - It consists of the oral cavity, pharynx, esophagus, There are two types of intestines namely large and stomach, small intestine, and large intestine. small intestines. - Digestion takes place within the oral cavity, Small intestines - The small intestine is about 2.5 stomach, and small intestine; most absorption of centimeter in diameter and 6 meters long. Its wall is nutrients takes place in the small intestine. made of smooth muscles. - Indigestible material, primarily cellulose, is Its work is to digest food, which can then be eliminated by the large intestine (also called the absorbed by the blood colon). - The body’s major digestive organ b. The accessory organs: these are the teeth, - Site of nutrient absorption into the blood tongue, salivary glands, liver, gallbladder, and Large intestines - The large intestine is about 5 pancreas. centimeters in diameter and about 1.8 meters long. Digestion does not take place within these Its main part of the colon. At the end of the colon is organs, but each contributes something to the rectum which opens to the anus. the digestive process. The work of the large intestine is to absorb water Main parts and functions of Digestive System from the undigested food, hold the undigested food 1. Mouth - is the first part of the digestive tract. The for a while and then excrete it as feces. tongue and the teeth are found in the mouth. - Larger in diameter, but shorter than the small The inside of the mouth is lubricated with saliva intestine. that comes from the salivary glands. The strongest - Absorption of water - Eliminates indigestible food from the body as feces  - Does not participate in digestion of food - Helps to form a food bolus - Goblet cells produce mucus to act as a lubricant - Contains salivary amylase to begin starch digestion Accessory Parts of the Digestive System and their - Dissolves chemicals so they can be tasted functions: 5. Teeth - The role is to masticate (chew) food The liver, pancreas and gall bladder are not part of Two sets of teeth the alimentary canal but they have important a. Deciduous (baby or milk) teeth - 20 teeth are functions in the digestive process. They are called fully formed by age two accessory parts of the digestive system. b. Permanent teeth - Replace deciduous teeth 1. Liver - The liver lies under the diaphragm and beginning between the ages of 6 to 12. A full set is near the stomach. 32 teeth, but some people do not have wisdom It is the largest organ inside the body and one of the teeth. most important. 6. Tongue – it is where the taste buds are located. - Considered the largest gland, it performs over 500 functions that influence several systems beside the V – Respiratory System - The respiratory system is digestive system. In regards to the digestive system the group of tissues and organs in your body that it produces bile. A substance that emulsifies fat and enable you to breathe makes it accessible to fat digesting enzymes. The The respiratory system's primary function is to liver is involved in balancing blood glucose levels, it supply oxygen to all the parts of your body. responds to hormones, and clears toxins or drugs It accomplishes this through breathing: from the blood and makes blood proteins. inhaling oxygen-rich air and exhaling air filled with Among the functions of the liver that are related to carbon dioxide, which is a waste gas. digestion are the following: Main Parts of the Respiratory System and their a. It produces bile, a substance that helps in Function: the digestion of fats. 1. Nostrils - are involved in air intake, i.e. they bring b. It stores glycogen, vitamins and some air into the nose, where air is warmed and minerals, such as iron and copper, which humidified. are released when needed by the body. The tiny hairs called cilia filters out dust and 2. Gall Bladder - The gall bladder is a small muscular other particles present in the air and protects the sac that is attached beneath the liver. nasal passage and other regions of the respiratory Bile produced by the liver passes through a tract small tube and is stored in the gall bladder. 2. Trachea – is known as windpipes. The trachea From the gall bladder, bile is released to the filters the air we inhaled and branches into the small intestine digestion. bronchi. - Muscular sac that stores bile, it is attached to the - is the passage leading from the pharynx to the cystic duct and when the muscle contract bile exits lungs. through this duct and into the common hepatic 3. Bronchi – are the two air tubes that branch off duct. from the trachea and carry atmospheric air is 3. Pancreas - The pancreas is an organ that lies directly into the lungs. behind the stomach. Its function related to 4. Lungs - the main organ of the respiratory system digestion is to produce pancreatic juice. is lungs. Pancreatic juice helps in neutralizing or Lungs are the site in body where oxygen is weakening the acid in food inside the stomach taken into and carbon dioxide is expelled out. before it moves onto the small intestine. The red blood cells present in the blood Pancreatic juice also contains different picks up the oxygen in the lungs and carry and enzymes that are needed to further break down distribute the oxygen to all body cells that need i starch, proteins and fats in the small intestine. The red blood cells donate the oxygen to The pancreas is an organ that lies behind the the cells and picks up the carbon dioxide produced stomach. Its function related to digestion is to by the cells. produce pancreatic juice. 5. Alveolus - is the tiny sac like structure present in Pancreatic juice helps in neutralizing or the lungs which the gaseous exchange takes place. weakening the acid in food inside the stomach 6. Diaphragm - breathing begins with a dome- before it moves onto the small intestine. shaped muscle located at the bottom of the lungs Pancreatic juice also contains different which is known as diaphragm. enzymes that are needed to further break down When we breathe in the diaphragm starch, proteins and fats in the small intestine. contracts and flatten out and pull downward. 4. Salivary Glands - Saliva-producing glands Due to this movement the space in the - Parotid glands – located anterior to ears lungs increases and pulls air into the lungs. - Submandibular glands When we breathe out, the diaphragm - Sublingual glands expands and reduces the amount of space for the Saliva - Mixture of mucus and serous fluids lungs and forces air out. Other Parts of the Respiratory System and their to the affected site, which quickly stop bleeding and Function: promote healing. 1. Sinuses - Are hollow spaces in the bones of the The circulatory system has three (3) main parts. The head. heart is the main pump of the circulatory system. The functions they serve are not clearly Blood is a liquid tissue containing blood cells in understood, but include helping to regulate the suspension. Blood vessels are the tubes through temperature and humidity of air breathed in, as which blood flows to and from different parts of an well as to lighten the bone structure of the head animal. and to give resonance to the voice. The heart is a strong, powerful organ, consisting of 2. Nasal Cavity - is the preferred entrance for cardiac muscle. The heart pumps continuously, outside air into the Respiratory System. without resting and without becoming fatigued. Its The hairs that line the inside wall are part of function is to pump blood to the lungs and around the air-cleansing system. the body. 3. Oral Cavity - is another the entrance for outside What happens to the blood in veins? air into the Respiratory System. - Your veins carry blood back to your heart. The 4. Adenoids - are overgrown lymph tissue at the top chambers on the right side of your heart take care of the throat. of blood coming back through your veins. First, the The lymph system, consisting of nodes blood comes into your right atrium, the top (knots of cells) and connecting vessels, carries fluid chamber. Your right atrium pumps the blood into throughout the body. your right ventricle, the bottom chamber. Your right This system helps resist body infection by ventricle pumps the blood through an artery into filtering out foreign matter, including germs, and your lungs. producing cells (lymphocytes) to fight them. What happens to blood in the lungs? 5. Tonsils - are lymph nodes in the wall of the - Your blood has to get rid of carbon dioxide. It has pharynx that often become infected. to get a fresh supply of oxygen. Your lungs take care They are an unimportant part of the germ- of both jobs. Carbon dioxide from your blood goes fighting system of the body. When infected, they into your lungs. Your lungs get rid of the carbon are generally removed. dioxide when you breathe out. 6. Pharynx (throat) - collects incoming air from the - Then you breathe in. Your lungs get oxygen from nose and passes it downward to the trachea breathing in air. Your lungs fill up with oxygen. Your (windpipe). blood picks up a new supply of oxygen from your 7. Epiglottis - is a flap of tissue that guards the lungs. Now your blood is ready to go out through entrance to the trachea, closing when anything is your arteries to all the parts of your body. swallowed that should go into the esophagus and - The chambers on the left side of your heart take stomach. care of blood going out through your arteries. 8. Larynx (voice box) - contains the vocal cords. It is Special veins send blood from your lungs to your the place where moving air being breathed in and left atrium, or top chamber. The blood goes from out creates voice sounds. the left atrium to the left ventricle. The left ventricle 9. Esophagus - is the passage leading from the pumps the blood out through your arteries to every mouth and throat to the stomach. part of your body. 10. Ribs - are bones supporting and protecting the Human Blood Vessels: chest cavity. They move to a limited degree, helping Arteries - vessels that carry blood away from the the lungs to expand and contract. heart. Two arteries have direct connection with the heart: VI – Circulatory System - Circulatory System, or (1) the aorta, which, with its branches, conveys cardiovascular system, in humans, the combined oxygenated blood from the left ventricle to every function of the heart, blood, and blood vessels to part of the body; and transport oxygen and nutrients to organs and (2) the pulmonary artery, which conveys blood tissues throughout the body and carry away waste from the right ventricle to the lungs, whence it is products. Among its vital functions, the circulatory returned bearing oxygen to the left side of the system increases the flow of blood to meet heart. increased energy demands during exercise and Capillaries - Capillary, one of the minute blood regulates body temperature. In addition, when vessels that form the connection between the foreign substances or organisms invade the body, arteries and the veins. The walls of capillaries are the circulatory system swiftly conveys disease- exceedingly thin and readily permeable. They are fighting elements of the immune system, such as surrounded by lymph, and there is a constant white blood cells and antibodies, to regions under interchange between the substances in the blood attack. Also, in the case of injury or bleeding, the within the capillaries and the waste products in the circulatory system sends clotting cells and proteins body tissues and lymph outside. This interchange facilitates the processes of nutrition and elimination and enables the exchange of oxygen and carbon Nervous System Organization dioxide to take place. Lymph capillaries assist the blood capillaries in this process. - One-celled organisms and many simple multicelled animals, such as sponges, jellyfishes, sea anemones, flatworms, and roundworms, do not have a circulatory system. All of their cells are able to absorb nutrients, exchange gases, and expel wastes through direct contact with either the outside or with a central cavity that serves as a digestive tract. Circulation in Invertebrate: - More complex invertebrates have a wide range of circulatory system designs. These invertebrate circulatory systems are classified as either open or closed. Open systems—found in starfishes, clams, oysters, snails, crabs, insects, spiders, and centipedes—lack capillaries, and the blood bathes the tissues directly. In closed systems, the blood is confined to a system of blood vessels. Invertebrates with closed systems include segmented worms, squids, and octopuses. - All vertebrate animals have closed circulatory systems. These systems are classified by the number of chambers in the heart, which determines the basic configuration of blood flow. Fish have two-chambered hearts with one atrium and one ventricle. Blood pumped from the ventricle travels through arteries to the gills, where it diverges into capillaries and exchanges gases. Leaving the gills, The Central Nervous System (CNS) the capillaries reconvene into blood vessels that - Central Nervous System is effectively the centre carry the oxygenated blood to the rest of the body, of the nervous system, the part of it that processes where the vessels again diverge into capillaries the information received from the peripheral before reconvening into veins that return to the nervous system. The CNS consists of the brain and heart. In this way, the blood passes through first the spinal cord. It is responsible for receiving and respiratory organs (the gills) and then the systemic interpreting signals from the peripheral nervous circulation between each pass through the heart. system and also sends out signals to it, either consciously or unconsciously. This information VII – Nervous System - The Nervous system is highway called the nervous system consists of many essentially a biological information highway, and is nerve cells, also known as neurons. responsible for controlling all biological processes 1. Brain -is the center of the nervous system. and movement in the body, and can also receive 2. Spinal Cord- The spinal cord is a long, thin, information and interpret it via electrical signals tubular bundle of nervous tissue and support which are used in the nervous system. cells that extends from the brain - those elements within the animal organism that Brain Division: are concerned with the reception of stimuli, the 3 Main Components of Brain transmission of nerve impulses, or the activation of 1. Brainstem muscle mechanisms. 2. Cerebellum 3. Forebrain The Brainstem – is the connection between the rest of the brain and the rest of the central nervous system. This part of the brain was the first to be found in the evolutionary chain, though has developed over time and via evolution to develop into the two other components. It is primarily concerned with life support and basic functions such as movement. The Cerebellum – consist of two hemispheres, the cerebellum is primarily concerned with movement and works in partnership with the brainstem area of the brain and focuses on the well being and functionality of muscles. The structure can be found below the occipital lobe and adjacent to the brainstem. The Forebrain – The forebrain lies above the brainstem and cerebellum and is the most advanced in evolutionary terms. Due to its complexity, more info is divulged about this part of the brain below. Other Parts of Brain: Hypothalamus Cerebrum Cerebral Cortex a. Frontal Lobe b. Parietal Lobe The Autonomic Nervous System (ANS) c. Temporal Lobe The autonomic nervous system incorporates all the d. Occipital Lobe impulses that are done involuntarily, and are usually The Hypothalamus – A section of the brain found associated with essential functions such as next to the thalamus that is involved in many breathing, heartbeat etc. However this type of regulatory functions such as osmoregulation and system can further be broken down into the thermoregulation. sympathetic and parasympathetic systems which The Cerebrum – The cerebrum is the largest part of keep one another in check in a form of negative the human brain, and the part responsible for feedback such as the release of insulin and glucagon intelligence and creativity, and also involved in in sugar control of the blood. memory. The 'grey matter' of the cerebrum is the cerebral cortex, the centre that receives information from the thalamus and all the other lower centers in the brain. The Cerebral Cortex - Part of the cerebrum, this part of the brain deals with almost all of the higher functions of an intelligent being. It is this part of brain that deals with the masses of information incoming from the periphery nervous system, furiously instructing the brain of what is going on inside So important is the cerebral cortex that it is sub-divided into 4 parts. a. Frontal Lobe – Found at the front of the head, near the temples and forehead, the frontal lobe is essential to many of the advanced functions of an evolved brain. It deals with voluntary muscle movements and deals with more intricate matters Somatic Nervous System -These efferent fibers are such as thought and speech. divided into the somatic nervous system and the b. Parietal Lobe - Situated behind the frontal lobe, autonomic nervous system. The somatic fibers are this section deals with spatial awareness in the responsible for the voluntary movement of our external environment and acts as a receptor area to body, i.e. movement that you consciously thought deal with signals associated with tough. about doing. c. Temporal Lobe – The temporal lobes are situated in parallel with the ears, they serve the ears by interpreting audio signals received from the auditory canal. d. Occipital Lobe – This is the smallest of the four lobe components of the cerebrum, and is responsible in interpreting nerve signals from the eye at the back of the brain. Anatomy and Functions - Some of the processes of the cell bodies conduct - The reception of stimuli is the function of special sense impressions and others conduct muscle sensory cells. responses, called reflexes, such as those caused by - The conducting elements of the nervous system pain. are cells called neurons; these may be capable of - In the skin are cells of several types called only slow and generalized activity, or they may be receptors; each is especially sensitive to particular highly efficient and rapidly conducting units. stimuli. - The specific response of the neuron—the nerve - Free nerve endings are sensitive to pain and are impulse—and the capacity of the cell to be directly activated. stimulated make this cell a receiving and - The neurons so activated send impulses into the transmitting unit capable of transferring central nervous system and have junctions with information from one part of the body to another. other cells that have axons extending back into the A. Nerve Cell periphery. - Each nerve cell consists of a central portion - Impulses are carried from processes of these cells containing the nucleus, known as the cell body, and to motor endings within the muscles. one or more structures referred to as axons and - These neuromuscular endings excite the muscles, dendrites. resulting in muscular contraction and appropriate - The dendrites are rather short extensions of the movement. cell body and are involved in the reception of - The pathway taken by the nerve impulse in stimuli. mediating this simple response is in the form of a - The axon, by contrast, is usually a single elongated two-neuron arc that begins and ends in the extension; it is especially important in the periphery. transmission of nerve impulses from the region of - Many of the actions of the nervous system can be the cell body to other cells. explained on the basis of such reflex arcs, which are B. Simple System chains of interconnected nerve cells, stimulated at - Although all many-celled animals have some kind one end and capable of bringing about movement of nervous system, the complexity of its or glandular secretion at the other. organization varies considerably among different D. The Nerve Network animal types. - The cranial nerves connect to the brain by passing - In simple animals such as jellyfish, the nerve cells through openings in the skull, or cranium. form a network capable of mediating only a - Nerves associated with the spinal cord pass relatively stereotyped response. through openings in the vertebral column and are - In more complex animals, such as shellfish, insects, called spinal nerves. and spiders, the nervous system is more - Both cranial and spinal nerves consist of large complicated. numbers of processes that convey impulses to the - The cell bodies of neurons are organized in central nervous system and also carry messages clusters called ganglia. outward; the former processes are called afferent, - These clusters are interconnected by the neuronal the latter are called efferent. processes to form a ganglionated chain. - Afferent impulses are referred to as sensory; - Such chains are found in all vertebrates, in which efferent impulses are referred to as either somatic they represent a special part of the nervous system, or visceral motor, according to what part of the related especially to the regulation of the activities body they reach. Most nerves are mixed nerves of the heart, the glands, and the involuntary made up of both sensory and motor elements. muscles. - The cranial and spinal nerves are paired; the C. Vertebrate System number in humans are 12 and 31, respectively. - Vertebrate animals have a bony spine and skull in - Cranial nerves are distributed to the head and which the central part of the nervous system is neck regions of the body, with one conspicuous housed; the peripheral part extends throughout the exception: the tenth cranial nerve, called the vagus. remainder of the body. - In addition to supplying structures in the neck, the - That part of the nervous system located in the vagus is distributed to structures located in the skull is referred to as the brain; that found in the chest and abdomen. spine is called the spinal cord. - Vision, auditory and vestibular sensation, and - The brain and the spinal cord are continuous taste are mediated by the second, eighth, and through an opening in the base of the skull; both seventh cranial nerves, respectively. are also in contact with other parts of the body - Cranial nerves also mediate motor functions of the through the nerves. head, the eyes, the face, the tongue, and the larynx, - The distinction made between the central nervous as well as the muscles that function in chewing and system and the peripheral nervous system is based swallowing. on the different locations of the two intimately related parts of a single system. - Spinal nerves, after they exit from the vertebrae, - For example, the virus causing poliomyelitis are distributed in a band like fashion to regions of commonly affects the spinal cord; viruses causing the trunk and to the limbs. encephalitis attack the brain. - They interconnect extensively, thereby forming - Inflammations of the nervous system are named the brachial plexus, which runs to the upper according to the part affected. extremities; and the lumbar plexus, which passes to - Myelitis is an inflammation of the spinal cord; the lower limbs. neuritis is an inflammation of a nerve. E. Automatic Nervous System - It may be caused not only by infection but also by - Among the motor fibers may be found groups that poisoning, alcoholism, or injury. carry impulses to viscera. - Tumors originating in the nervous system usually - These fibers are designated by the special name of are composed of meningeal tissue or neuroglia autonomic nervous system. (supporting tissue) cells, depending on the specific - That system consists of two divisions, more or less part of the nervous system affected, but other types antagonistic in function, that emerge from the of tumor may metastasize to or invade the nervous central nervous system at different points of origin. system. - One division, the sympathetic, arises from the - In certain disorders of the nervous system, such as middle portion of the spinal cord, joins the neuralgia, migraine, and epilepsy, no evidence may sympathetic ganglionated chain, courses through exist of organic damage. the spinal nerves, and is widely distributed - Another disorder, cerebral palsy, is associated with throughout the body. birth defects. - The other division, the parasympathetic, arises both above and below the sympathetic, that is, VIII – Endocrine System - The endocrine system from the brain and from the lower part of the spinal includes all of the glands of the body and the cord. hormones produced by those glands. The glands are - These two divisions control the functions of the controlled directly by stimulation from the nervous respiratory, circulatory, digestive, and urogenital system as well as by chemical receptors in the blood systems. and hormones produced by other glands. By Nervous System Disorders regulating the functions of organs in the body, - Consideration of disorders of the nervous system these glands help to maintain the body’s is the province of neurology; psychiatry deals with homeostasis. Cellular metabolism, reproduction, behavioral disturbances of a functional nature. sexual development, sugar and mineral - The division between these two medical homeostasis, heart rate, and digestion are among specialties cannot be sharply defined, because the many processes regulated by the actions of neurological disorders often manifest both organic hormones. and mental symptoms. - Endocrine System, group of specialized organs and - For a discussion of functional mental illness, body tissues that produce, store, and secrete Mental Illness. chemical substances known as hormones. - Diseases of the nervous system include genetic - As the body's chemical messengers, hormones malformations, poisonings, metabolic defects, transfer information and instructions from one set vascular disorders, inflammations, degeneration, of cells to another. and tumors, and they involve either nerve cells or - Because of the hormones they produce, endocrine their supporting elements. organs have a great deal of influence over the body. - Vascular disorders, such as cerebral hemorrhage - Among their many jobs are regulating the body's or other forms of stroke, are among the most growth and development, controlling the function common causes of paralysis and other neurologic of various tissues, supporting pregnancy and other complications. reproductive functions, and regulating metabolism. - Some diseases exhibit peculiar geographic and age - Endocrine organs are sometimes called ductless distribution. glands because they have no ducts connecting them - In temperate zones, multiple sclerosis is a to specific body parts. common degenerative disease of the nervous - The hormones they secrete are released directly system, but it is rare in the Tropics. into the bloodstream. In contrast, the exocrine - The nervous system is subject to infection by a glands, such as the sweat glands or the salivary great variety of bacteria, parasites, and viruses. glands, release their secretions directly to target - For example, meningitis, or infection of the areas—for example, the skin or the inside of the meninges investing the brain and spinal cord, can mouth. be caused by many different agents. - Some of the body's glands are described as endo- - On the other hand, one specific virus causes exocrine glands because they secrete hormones as rabies. Some viruses causing neurological ills affect well as other types of substances. Even some non- only certain parts of the nervous system. glandular tissues produce hormone-like substances—nerve cells produce chemical Anterior Pituitary – messengers called neurotransmitters, for example. The anterior pituitary gland is the true glandular - The earliest reference to the endocrine system part of the pituitary gland. The function of the comes from ancient Greece, in about 400 bc. anterior pituitary gland is controlled by the - However, it was not until the 16th century that releasing and inhibiting hormones of the accurate anatomical descriptions of many of the hypothalamus. The anterior pituitary produces 6 endocrine organs were published. important hormones: - Research during the 20th century and in the early Thyroid stimulating hormone (TSH), as its name 21st century vastly improved our understanding of suggests, is a tropic hormone responsible for the hormones and how they function in the body. stimulation of the thyroid gland. - Today, endocrinology, the study of the endocrine Adrenocorticotropic hormone (ACTH) stimulates the glands, is an important branch of modern medicine. adrenal cortex, the outer part of the adrenal gland, - Endocrinologists are medical doctors who to produce its hormones. Follicle stimulating specialize in researching and treating disorders and hormone (FSH) stimulates the follicle cells of the diseases of the endocrine system. gonads to produce gametes—ova in females and Anatomy of the Endocrine System sperm in males. Hypothalamus- is a part of the brain located - Luteinizing hormone (LH) stimulates the gonads to superior and anterior to the brain stem and inferior produce the sex hormones—estrogens in females to the thalamus. It serves many different functions and testosterone in males. in the nervous system, and is also responsible for - Human growth hormone (HGH) affects many the direct control of the endocrine system through target cells throughout the body by stimulating the pituitary gland. The hypothalamus contains their growth, repair, and reproduction. special cells called neurosecretory cells—neurons - Prolactin (PRL) has many effects on the body, chief that secrete hormones. of which is that it stimulates the mammary Thyrotrophic-releasing hormone (TRH) glands of the breast to produce milk. Growth hormone-releasing hormone Pineal Gland- (GHRH) - The pineal gland is a small pinecone-shaped mass Growth hormone-inhibiting hormone of glandular tissue found just posterior to the (GHIH) thalamus of the brain. The pineal gland produces Gonadotropin-releasing hormone (GnRH) the hormone melatonin that helps to regulate the Corticotrophin-releasing hormone (CRH) human sleep-wake cycle known as the circadian Oxytocin rhythm. The activity of the pineal gland is inhibited Ant diuretic hormone (ADH) by stimulation from the photoreceptors of the Pituitary Gland- retina. The pituitary gland, also known as the hypothesis, Thyroid Gland- is a small pea-sized lump of tissue connected to the The thyroid gland is a butterfly-shaped gland inferior portion of the hypothalamus of the brain. located at the base of the neck and wrapped Many blood vessels surround the pituitary gland to around the lateral sides of the trachea. The thyroid carry the hormones it releases throughout the gland produces 3 major hormones: body. Situated in a small depression in the sphenoid a. Calcitonin bone called the sell Turkic, the pituitary gland is b. Triiodothyronine (T3) actually made of 2 completely separate structures: c. Thyroxin (T4) the posterior and anterior pituitary glands. Calcitonin is released when calcium ion levels in the Posterior Pituitary - The posterior pituitary gland is blood rise above a certain set point. Calcitonin actually not glandular tissue at all, but nervous functions to reduce the concentration of calcium tissue instead. The posterior pituitary is a small ions in the blood by aiding the absorption of extension of the hypothalamus through which the calcium into the matrix of bones. The hormones T3 axons of some of the neurosecretory cells of the and T4 work together to regulate the body’s hypothalamus extend. These neurosecretory cells metabolic rate. Increased levels of T3 and T4 lead to create 2 hormones in the hypothalamus that are increased cellular activity and energy usage in the stored and released by the posterior pituitary. body. - Oxytocin triggers uterine contractions during Parathyroid Glands- childbirth and the release of milk during The parathyroid glands are 4 small masses of breastfeeding. glandular tissue found on the posterior side of the - * Ant diuretic hormone (ADH) prevents water loss thyroid gland. The parathyroid glands produce the in the body by increasing the re-uptake of water in hormone parathyroid hormone (PTH), which is the kidneys and reducing blood flow to sweat involved in calcium ion homeostasis. PTH is released glands. from the parathyroid glands when calcium ion levels in the blood drop below a set point. PTH stimulates the osteoclasts to break down the calcium containing bone matrix to release free calcium ions The testes are a pair of ellipsoid organs found in the into the bloodstream. PTH also triggers the kidneys scrotum of males that produce the androgen to return calcium ions filtered out of the blood back testosterone in males after the start of puberty. to the bloodstream so that it is conserved. Testosterone has effects on many parts of the body, Adrenal Glands- including the muscles, bones, sex organs, and hair The adrenal glands are a pair of roughly triangular follicles. This hormone causes growth and increases glands found immediately superior to the kidneys. in strength of the bones and muscles, including the The adrenal glands are each made of 2 distinct accelerated growth of long bones during layers, each with their own unique functions: the adolescence. outer adrenal cortex and inner adrenal medulla. Ovaries – - Adrenal cortex - The adrenal cortex produces The ovaries are a pair of almond-shaped glands many cortical hormones in 3 classes: located in the pelvic body cavity lateral and superior glucocorticoids, mineral corticoids, and androgens. to the uterus in females. The ovaries produce the - Glucocorticoids have many diverse functions, female sex hormones progesterone and estrogens. including the breakdown of proteins and lipids to Progesterone is most active in females during produce glucose. Glucocorticoids also function to ovulation and pregnancy where it maintains reduce inflammation and immune response. appropriate conditions in the human body to - Mineral corticoids, as their name suggests, are a support a developing fetus. Estrogens are a group of group of hormones that help to regulate the related hormones that function as the primary concentration of mineral ions in the body. female sex hormones. - Androgens, such as testosterone, are produced at Thymus- low levels in the adrenal cortex to regulate the The thymus is a soft, triangular-shaped organ found growth and activity of cells that are receptive to in the chest posterior to the sternum. The thymus male hormones. In adult males, the amount of produces hormones called thymuses that help to androgens produced by the testes is many times train and develop T-lymphocytes during fetal greater than the amount produced by the adrenal development and childhood. The T-lymphocytes cortex, leading to the appearance of male produced in the thymus go on to protect the body secondary sex characteristics. from pathogens throughout a person’s entire life. Adrenal medulla - The adrenal medulla produces Other Hormone Producing Organs the hormones epinephrine and nor epinephrine In addition to the glands of the endocrine system, under stimulation by the sympathetic division of the many other non-glandular organs and tissues in the autonomic nervous system. Both of these hormones body produce hormones as well. help to increase the flow of blood to the brain and Heart: The cardiac muscle tissue of the heart is muscles to improve the “fight-or-flight” response to capable of producing the hormone atria natriuretic stress. peptide (ANP) in response to high blood pressure Pancreas levels. ANP works to reduce blood pressure by The pancreas is a large gland located in the triggering vasodilatation to provide more space for abdominal cavity just inferior and posterior to the blood to travel through. the stomach. The pancreas is considered to be a Kidneys - heteroclite gland as it contains both endocrine and The kidneys produce the hormone erythropoietin exocrine tissue. The endocrine cells of the pancreas (EPO) in response to low levels of oxygen in the make up just about 1% of the total mass of the blood. EPO released by the kidneys travels to the pancreas and are found in small groups throughout red bone marrow where it stimulates an increased the pancreas called islets of Langerhans. Within production of red blood cells. The number of red these islets are 2 types of cells—alpha and beta blood cells increases the oxygen carrying capacity of cells. The alpha cells produce the hormone the blood, eventually ending the production of EPO. glucagon, which is responsible for raising blood Digestive System - glucose levels. Glucagon triggers muscle and liver The hormones cholecystokinin (CCK), secreting, and cells to break down the polysaccharide glycogen to gastric are all produced by the organs of the release glucose into the bloodstream. The beta cells gastrointestinal tract. CCK, secreting, and gastric all produce the hormone insulin, which is responsible help to regulate the secretion of pancreatic juice, for lowering blood glucose levels after a meal. bile, and gastric juice in response to the presence of Gonads- food in the stomach. CCK is also instrumental in the The gonads, ovaries in females and testes in sensation of satiety or “fullness” after eating a males—are responsible for producing the sex meal. hormones of the body. These sex hormones Adipose – determine the secondary sex characteristics of adult Adipose tissue produces the hormone lepton that is females and adult males. involved in the management of appetite and energy Testes – usage by the body. Lepton is produced at levels relative to the amount of adipose tissue in the body, allowing the brain to monitor the body’s chemicals that either stimulate or suppress energy storage condition. When the body contains a hormone secretions from the pituitary gland. sufficient level of adipose for energy storage, the - Acting as liaison between the brain and the level of lepton in the blood tells the brain that the pituitary gland, the hypothalamus is the primary body is not starving and may work normally. link between the endocrine and nervous systems. Placenta- - Located in a bony cavity just below the base of the In pregnant women, the placenta produces several brain is one of the endocrine system's most hormones that help to maintain pregnancy. important members: the pituitary gland. Progesterone is produced to relax the uterus, - Often described as the body’s master gland, the protect the fetus from the mother’s immune pituitary secretes several hormones that regulate system, and prevent premature delivery of the the function of the other endocrine glands. fetus. - Structurally, the pituitary gland is divided into two Local Hormones- parts, the anterior and posterior lobes, each having Prostaglandins and leukotrienes are produced by separate functions. every tissue in the body (except for blood tissue) in - The anterior lobe regulates the activity of the response to damaging stimuli. thyroid and adrenal glands as well as the Endocrine System Vs. Nervous System Function reproductive glands. The endocrine system works alongside of the - It also regulates the body's growth and stimulates nervous system to form the control systems of the milk production in women who are breast-feeding. body. The nervous system provides a very fast and Hormones secreted by the anterior lobe include narrowly targeted system to turn on specific glands adrenocorticotropic hormone (ACTH), thyrotropic and muscles throughout the body. The endocrine hormone (TSH), luteinizing hormone (LH), follicle- system, on the other hand, is much slower acting, stimulating hormone (FSH), growth hormone (GH), but has very widespread, long lasting, and powerful and prolactin. The anterior lobe also secretes effects. Hormones are distributed by glands through endorphins, chemicals that act on the nervous the bloodstream to the entire body, affecting any system to reduce sensitivity to pain cell with a receptor for a particular hormone. Most - The posterior lobe of the pituitary gland contains hormones affect cells in several organs or the nerve endings (axons) from the hypothalamus, throughout the entire body, leading to many which stimulate or suppress hormone production. diverse and powerful responses. - This lobe secretes antidiuretic hormones (ADH), Components of Endocrine System which control water balance in the body, and - The primary glands that make up the human oxytocin, which controls muscle contractions in the endocrine system are the hypothalamus, pituitary, uterus. thyroid, parathyroid, adrenal, pineal body, and - The thyroid gland, located in the neck, secretes reproductive glands—the ovary and testis. hormones in response to stimulation by TSH from - The pancreas, an organ often associated with the the pituitary gland. digestive system, is also considered part of the - The thyroid secretes hormones—for example, endocrine system. In addition, some none-ndocrine thyroxine and three-iodothyronine—that regulate organs are known to actively secrete hormones. growth and metabolism, and play a role in brain - These include the brain, heart, lungs, kidneys, development during childhood. liver, thymus, skin, and placenta. Almost all body - The parathyroid glands are four small glands cells can either produce or convert hormones, and located at the four corners of the thyroid gland. The some secrete hormones. hormone they secrete, parathyroid hormone, - For example, glucagon, a hormone that raises regulates the level of calcium in the blood. glucose levels in the blood when the body needs - Located on top of the kidneys, the adrenal glands extra energy, is made in the pancreas but also in the have two distinct parts. wall of the gastrointestinal tract. - The outer part, called the adrenal cortex, produces - However, it is the endocrine glands that are a variety of hormones called corticosteroids, which specialized for hormone production. They efficiently include cortisol. manufacture chemically complex hormones from - These hormones regulate salt and water balance simple chemical substances—for example, amino in the body, prepare the body for stress, regulate acids and carbohydrates—and they regulate their metabolism, interact with the immune system, and secretion more efficiently than any other tissues. influence sexual function. - The hypothalamus, found deep within the brain, - The inner part, the adrenal medulla, produces directly controls the pituitary gland. It is sometimes catecholamines, such as epinephrine, also called described as the coordinator of the endocrine adrenaline, which increase the blood pressure and system. heart rate during times of stress. - When information reaching the brain indicates - The reproductive components of the endocrine that changes are needed somewhere in the body, system, called the gonads, secrete sex hormones in nerve cells in the hypothalamus secrete body response to stimulation from the pituitary gland. - Located in the pel