Chapter 10 Review of Human Systems PDF

© fStop /Getty Images Chapter 10 Review of Human Systems NATIONAL EMS EDUCATION STANDARD COMPETENCIES Anatomy and Physiology Integrates a complex depth and comprehensive breadth of knowledge of the anatomy and physiology of all human systems. OBJECTIVES Upon completion of this chapter, the param...

© fStop /Getty Images Chapter 10 Review of Human Systems NATIONAL EMS EDUCATION STANDARD COMPETENCIES Anatomy and Physiology Integrates a complex depth and comprehensive breadth of knowledge of the anatomy and physiology of all human systems. OBJECTIVES Upon completion of this chapter, the paramedic student will be able to: 1. Discuss the importance of human anatomy as it relates to the paramedic profession. (pp 199, 200) 2. Describe the anatomic position. (pp 199–200) 3. Properly interpret anatomic directional terms and body planes. (pp 200, 201) 4. List the structures that compose the axial and appendicular regions of the body. (p 200) 5. Define the divisions of the abdominal region. (pp 200–201) 6. List the three major body cavities. (pp 200, 202) 7. Describe the contents of the three major body cavities. (p 202) 8. Discuss the functions of the following cellular structures: the cytoplasmic membrane, the cytoplasm (and organelles), and the nucleus. (pp 202–206) 9. Describe the process by which human cells reproduce. (pp 206–207) 10. Differentiate and describe the following tissue types: epithelial tissue, connective tissue, muscle tissue, and nervous tissue. (pp 207–209) 11. For each of the 11 major organ systems in the human body, label a diagram of anatomic structures, list the functions of the major anatomic structures, and explain how the organs of the system interrelate to perform the specific functions of that system. (pp 209–261) 12. For the special senses, label a diagram of the anatomic structures of the special senses, list the functions of the anatomic structures of each sense, and explain how the structures of the senses interrelate to perform their specialized functions. (pp 261–265) KEY TERMS abdominal aorta The portion of the descending aorta that passes from the aortic hiatus of the diaphragm into the abdomen, where it divides into the two common iliac arteries. acetabulum The large, cup-shaped articular cavity at the juncture of the ilium, the ischium, and the pubis that contains the ball-shaped head of the femur. action potential A change in membrane potential in an excitable tissue that acts as an electrical signal and is propagated in an all-or-none fashion. adenosine triphosphate (ATP) A nucleotide composed of adenosine, an organic base, with three phosphate groups attached to it. It stores energy in muscles. adipose tissue A specialized connective tissue that stores lipids; also known as fat tissue. aerobic oxidation A biochemical reaction that increases the positive charges on an atom or the loss of negative charges in the presence of oxygen. 191 afferent division The division of the peripheral nervous system that transmits impulses from the periphery to the central nervous system. afferent neurons Neurons that carry action potentials from the periphery to the central nervous system. aldosterone A steroid hormone produced by the adrenal cortex to regulate the sodium and potassium balance in the blood. alveoli Minute air sacs in the lungs through which gas exchange takes place between alveolar air and pulmonary capillary blood. amino acids Organic chemical compounds composed of one or more basic amino groups and one or more acidic carboxyl groups. anatomic position The position of standing erect with the feet and palms facing the examiner. anterior The front, or ventral, surface. antidiuretic hormone (ADH) A hormone produced in the posterior pituitary gland that regulates the balance of water in the body by accelerating the resorption of water. anus The distal end or outlet of the rectum. aorta The main and largest artery in the body. appendicular region The region consisting of the limbs, or extremities. appendicular skeleton The bones of the upper and lower extremities. aqueous humor The clear, watery fluid that circulates in the anterior and posterior chambers of the eye. arachnoid layer The delicate, weblike, middle membrane that covers the brain. areola The circular, pigmented area surrounding the nipple. areolar connective tissue A loose tissue that consists of delicate webs of fibers and a variety of cells embedded in a matrix of soft, sticky gel. arterioles Small branches of arteries. arteriovenous anastomoses Vessels that allow blood to flow from arteries to veins without passing through capillaries; also known as arteriovenous shunts. atria The two upper chambers of the heart (singular, atrium). atrial natriuretic factor (ANF) A peptide released from the atria when atrial blood pressure is increased. It lowers blood pressure by increasing urine production, thereby reducing blood volume. atrioventricular node An area of specialized cardiac muscle that receives the cardiac impulse from the sinoatrial node and conducts it to the bundle of His. atrioventricular valve A valve in the heart through which blood flows from the atria to the ventricles. 192 auricle The part of the external ear that protrudes from the head; also known as the pinna. autonomic nervous system The division of the peripheral nervous system that acts as a control system for visceral processes. It functions largely below the level of consciousness. autonomic reflexes Any of a large number of normal reflexes governing and regulating the functions of the viscera autophagia A condition in which the body obtains nutrition through consumption of its own tissues. axial region The region consisting of the head, neck, thorax, and abdomen. axial skeleton The bones of the head, neck, and torso. bacteria Single-celled microorganisms that cause an infection characteristic of that species. basophils White blood cells that promote inflammation. bicuspid valve One of the two atrioventricular valves located between the left atrium and the ventricle; also known as the mitral valve. bile A bitter, yellow-green secretion of the liver that is stored in the gallbladder. blood The fluid and its suspended, formed elements that circulate through the heart, arteries, capillaries, and veins. bone A highly specialized form of hard, connective tissue. It consists of living cells and a mineralized matrix. bony labyrinth Part of the inner ear. It contains the membranous labyrinth. Bowman capsule The expanded beginning of a renal tubule. bronchioles Small branches of the bronchi. bulbourethral glands Small glands located just below the prostate gland that lubricate the terminal portion of the urethra and contribute to seminal fluid; also known as the Cowper glands. bundle of His A band of fibers in the myocardium through which the cardiac impulse is transmitted from the atrioventricular node to the ventricles. calcaneus The heel bone, the largest of the tarsal bones. cancellous bone Lattice-like tissue normally present in the interior of many bones, where spaces usually are filled with marrow; also known as spongy bone. capillaries Tiny vessels that connect arterioles to venules. cardiac muscle A special striated muscle of the myocardium that contains dark, intercalated disks at the junctions of the abutting fibers. It is characterized by special contractile abilities. cardiac output The volume of blood pumped each minute by the heart. cardiac sphincter A ring of muscle fibers at the juncture of the esophagus and the stomach. carina A downward and backward projection of the lowest tracheal cartilage, forming a ridge between the openings of the right and the left primary bronchi. carpal bones The bones of the carpus, or wrist. cartilage Firm, smooth, nonvascular connective tissue. cartilaginous joints Joints that are slightly movable. cecum A cul-de-sac constituting the first part of the large intestine. cell The functional basic unit of life. central nervous system (CNS) The system composed of the brain and spinal cord. centrioles Usually paired organelles that lie in the centrosome. centrosome A specialized zone of cytoplasm close to the nucleus that contains two centrioles. cerebellum The second largest part of the brain. It plays an essential role in coordinating normal movements. cerebral cortex A thin layer of gray matter, made up of neuron dendrites and cell bodies, that comprises the surface of the cerebrum. cerebrospinal fluid (CSF) The fluid that fills the subarachnoid space in the brain and spinal cord and is found in the cerebral ventricles. cerebrum The largest and uppermost part of the brain. It controls consciousness, memory, sensations, emotions, and voluntary movements. cervix The lower part of the uterus. chromatin granules The material within the cell nucleus from which chromosomes are formed. chromosomes Organized structures of deoxyribonucleic acid (DNA) and protein that are found in cells. chyme The semifluid mass of partly digested food passed from the stomach into the duodenum. cilia Small, hairlike processes on the outer surfaces of some cells. clitoris Erectile tissue in the vestibule of the vagina. compact bone Hard, dense bone that usually is found at the surface of skeletal structures, as distinguished from cancellous bone. conjunctiva A mucous membrane that covers the anterior surface of the eyeball and the lining of the eyelids. connective tissue Tissue that supports and binds other body tissues and parts. cornea The convex, transparent, anterior part of the eye. coronary arteries The two arteries that arise from the base of the aorta and carry blood to the muscle of the heart. costal cartilages Cartilages that connect the sternum and the ends of the ribs. They allow the chest to move in respiration. coxae The hip joints; the head of the femur and the acetabulum of the innominate bone. cranial vault The eight skull bones that surround and protect the brain; the brain case. cricoid cartilage The most inferior laryngeal cartilage. cricothyroid membrane The membrane joining the thyroid and cricoid cartilages. cytoplasm All of the substance of a cell other than the nucleus. cytoplasmic membrane The plasma membrane. deoxyribonucleic acid (DNA) A type of nucleic acid that makes up the genetic material of cells. dermatomes Areas of skin surface supplied by a single spinal nerve. dermis Dense, irregular connective tissue that forms the deep layer of the skin. diaphragm The dome-shaped, musculofibrous partition that separates the thoracic and abdominal cavities. diaphysis The shaft of a long bone, consisting of a tube of compact bone that encloses the medullary cavity. diencephalon The parts of the brain between the cerebral hemispheres and the mesencephalon. differentiation A process in which cells become specialized in one type of function or act in concert with other cells to perform a more complex task. dorsal root A sensory component that conveys afferent nerve processes to the spinal cord. ductus deferens A thick, smooth muscular tube that allows sperm to exit from the epididymis through the ejaculatory duct; also known as the vas deferens. duodenum The first subdivision of the small intestine. dura mater The outermost layer of the meninges. efferent division The division of the peripheral nervous system that transmits action potentials from the central nervous system to effector organs such as muscles and glands. efferent neurons Neurons that carry impulses away from the central nervous system to the periphery. electrolytes Cations or anions in solution that conduct an electrical current. endocrine glands Glands that secrete hormones into the blood rather than through a duct. 193 endocrine system A collection of glands that produce and secrete hormones. endoplasmic reticulum A network of connecting sacs or canals that wind through the cytoplasm of a cell, serving as a miniature circulatory system for the cell. enzymes A protein produced by living cells that catalyzes chemical reactions in organic matter. eosinophils White blood cells that inhibit inflammation. These readily stain with acidic dyes. epicardium The portion of the serous pericardium that covers the heart’s surface; also known as the visceral pericardium. epidermis The outer portion of the skin. It is formed of epithelial tissue that rests on or covers the dermis. epididymis A tightly coiled tube, lying along the top of and behind the testes, where sperm matures. epidural space The space above or on the dura. epiglottis A lidlike cartilage that overhangs the entrance to the larynx. epiphyseal plate The site of bone elongation; also known as the growth plate. epithelial tissue The cellular covering of internal and external surfaces of the body, including the lining of vessels and other small cavities. erection The condition of hardness, swelling, and elevation observed in the penis and to a lesser degree in the clitoris, usually caused by sexual arousal. erythrocytes Red blood cells. esophagus The muscular canal extending from the pharynx to the stomach. eukaryotes Cells with a true nucleus. They are found in all higher organisms and in some microorganisms. eustachian tube The auditory canal, which extends from the middle ear to the nasopharynx; also known as the auditory tube. exocrine gland A gland that secretes chemicals and hormones into a duct. external ear The portion of the ear that includes the auricle and external auditory meatus. It terminates at the eardrum. extracellular Occurring outside a cell or cell tissues or in cavities or spaces between cell layers or groups of cells. extracellular matrix Nonliving chemical substances located between connective tissue cells. femur The thigh bone, which extends from the pelvis to the knee; the largest and strongest bone in the body. fibrous connective tissue A connective tissue that consists mainly of bundles of strong, white collagenous fibers arranged in parallel rows. 194 fibrous joints Joints that are immovable. fibula A bone of the lower leg, lateral to and smaller than the tibia. flat bones Bones that have a thin, flattened shape, such as certain skull bones, the ribs, the sternum, and the scapulae. gallbladder A pear-shaped excretory sac on the visceral surface of the right lobe of the liver. It serves as a reservoir for bile. ganglia A group of nerve cell bodies in the peripheral nervous system. glomerulus The mass of capillary loops at the beginning of each nephron. glottic opening The vocal cords and the space between them. glycoproteins A large group of conjugated proteins in which the nonprotein substance is a carbohydrate. Golgi apparatus Specialized endoplasmic reticulum that concentrates and packages materials for secretion from the cell. gray matter The gray tissue that makes up the inner core of the spinal column. hematopoietic tissue Tissue related to the process of formation and development of various types of blood cells. hemoglobin A complex protein–iron compound in the blood that carries oxygen to the cells from the lungs and carbon dioxide away from the cells to the lungs. hepatic artery The branch of the aorta that delivers blood to the liver. histamine An amine released by mast cells and basophils that promotes inflammation. homeostasis A state of equilibrium in the body with respect to functions and composition of fluids and tissues. humerus The largest bone of the upper arm, comprising a body, head, and condyle. hymen A mucous membrane that may partly or entirely occlude the vaginal outlet. hyoid bone The U-shaped bone between the mandible and the larynx. hypothalamus A portion of the diencephalon of the brain that activates, controls, and integrates the peripheral autonomic nervous system, endocrine processes, and many somatic functions, such as body temperature, sleep, and appetite. ileum The distal portion of the small intestine. iliac crest The upper free margin of the ilium. ilium One of the three bones that make up the innominate bone. inferior Toward the feet; below a point of reference in the anatomic position. inferior vena cava The vein that returns blood from the lower limbs and the greater part of the pelvic and abdominal organs to the right atrium. inflammatory response A tissue reaction to injury or an antigen. It may include pain, swelling, itching, redness, heat, and loss of function. inguinal canal The passage through the lower abdominal wall that transmits the spermatic cord in the male and the round ligament in the female. inner ear The part of the ear that contains the sensory organs for hearing and balance. integumentary system The largest organ system in the body, consisting of the skin and accessory structures. intercellular Occurring between or among cells. interstitial fluid Fluid that occupies the space outside the blood vessels and/or outside the cells of an organ or tissue. intracellular Occurring within cell membranes. intraocular pressure Pressure within the eye that keeps the eye inflated. ions Atoms or groups of atoms that carry a charge of electricity by virtue of having gained or lost one or more electrons. iris The colored contractile membrane of the eye that can be seen through the cornea. irregular bones Bones that are not representative of the other three categories (long, short, or flat bones). ischium One of the three parts of the hipbone. It joins the ilium and the pubis to form the acetabulum. jejunum One of the three portions of the small intestine. joint capsule A well-defined structure that encloses a joint. jugular notch The superior margin of the manubrium, which is palpated easily at the anterior base of the neck; also known as the suprasternal notch. kidney One of the pair of organs that cleanse the body of the waste products continually produced by metabolism. Krebs cycle A sequence of enzymatic reactions, involving the metabolism of carbon chains of sugar, fatty acids, and amino acids, that yield carbon dioxide, water, and high-energy phosphate bonds. lacrimal gland The tear gland located in the superolateral corner of the orbit. large intestine The portion of the digestive tract comprising the cecum; the appendix; the ascending, transverse, and descending colons; and the rectum. laryngopharynx The lowest part of the pharynx. larynx The voice box, located just below the pharynx. lateral recumbent A position in which the patient lies on the right or left side. left atrium One of the four chambers of the human heart. It receives oxygenated blood from the lungs and pumps it into the left ventricle. lens The crystalline portion of the eye. leukocytes White blood cells. limbic system The part of the brain involved with emotions and olfaction. lipid bilayer The central layer of the cytoplasmic membrane. It is composed of a double layer of lipid molecules. lipoproteins Conjugated proteins in which lipids form an integral part of the molecule. They are synthesized primarily in the liver. liver An organ in the upper abdomen that aids in digestion and removes waste products and cellular debris from the blood; the largest solid organ in the human body. long bones Bones that are longer than they are wide, such as the humerus, ulna, radius, femur, tibia, fibula, and phalanges. loop of Henle The U-shaped portion of the renal tubule. lymph nodes Encapsulated masses of lymphoid tissue found among lymph vessels. lymph nodules Small, densely packed spherical nodes or aggregations of lymph cells embedded in the reticular meshwork of the lymphatic system. They are found mainly in the tonsils, spleen, and thymus. lymphatic system The network of vessels, ducts, nodes, valves, and organs involved in protecting and maintaining the internal fluid environment of the body. lymphocytes A type of white blood cell formed in lymphoid tissue. lysosomes Membranous-walled organelles that contain enzymes, which enable the lysosome to function as an intracellular digestive system. macrophages Phagocytic cells in the immune system. mammary glands External accessory sex organs in females; the breasts. medial malleolus The rounded process on the medial side of the ankle joint. mediastinum The area of the body that includes the trachea, esophagus, thymus, heart, and great vessels. medulla The lowest part of the brainstem, which controls vital functions; an enlarged extension of the spinal cord; also known as the medulla oblongata. 195 meninges Fluid-containing membranes surrounding the brain and spinal cord. mesencephalon One of the three parts of the brainstem; also known as the midbrain. mesentery A continuous abdominal organ composed of a double fold of peritoneum that holds other abdominal organs to the body wall. metabolism The culmination of all chemical processes that take place in living organisms. metacarpals The five bones that extend from the carpus to the phalanges. metatarsals The five bones that compose the metatarsus. middle ear An air-filled space in the temporal bone that contains the auditory ossicles. mitochondria Small, spherical, rod-shaped or thin filamentous structures in the cytoplasm of cells; a site of adenosine triphosphate production. mitosis Cell division that results in two daughter cells with exactly the same number and type of chromosomes as the mother cell. monocytes A type of white blood cell found in the lymph nodes, spleen, bone marrow, and loose connective tissue. mons pubis The prominence caused by a pad of fatty tissue over the symphysis pubis in the female. motor neuron A neuron that innervates muscle fibers. mucus The viscous, slippery secretion of mucous membranes and glands. mycoplasmas A genus of microscopic organisms that lack rigid cell walls; considered the smallest free-living organisms. myofilaments Extremely fine, molecular, threadlike structures that help form the myofibril of muscle. Thick myofibrils are formed of myosin, and thin myofilaments are formed of actin. nephron The functional unit of the kidney. neuroglia The supporting or nonneuronal tissue cells of the central and peripheral nervous system. neurons The functional units of the nervous system, consisting of the nerve cell body, the dendrites, and the axon. neutrophils Small, phagocytic white blood cells with a lobed nucleus and small granules in the cytoplasm. nucleoplasm The protoplasm of the nucleus, as contrasted with that of the cell. nucleus The central controlling body within a living cell. obturator foramen A large opening on each side of the lower portion of the hipbone, formed posteriorly by the ischium, superiorly by the ilium, and anteriorly by the pubis. 196 oculomotor nerve The third cranial nerve, which contains sensory and motor fibers. It provides for movement of most of the muscles of the eye, for constriction of the pupil, and for accommodation of the eye to light. olfactory Of or pertaining to the sense of smell. oocytes Incompletely developed ova. optic nerve The nerve that carries visual signals from the eye to the crossing of the optic tracts. organ A structure made up of two or more kinds of tissues organized to perform a more complex function than any one tissue alone. organelles Various particles of living substance that are bound within most cells, such as the mitochondria, the Golgi apparatus, the endoplasmic reticulum, the lysosomes, and the centrioles. ovarian follicles Spherical cell aggregations in the ovary that contain an oocyte. ovaries The pair of female gonads found on each side of the lower abdomen beside the uterus. pancreas A fish-shaped, nodular gland located across the posterior abdominal wall in the epigastric region of the body. It secretes various substances, including digestive enzymes, insulin, and glucagon. parasympathetic nervous system The subdivision of the autonomic nervous system, usually involved in activating vegetative functions such as digestion, defecation, and urination. parietal peritoneum The serous membrane that covers the body cavity wall. patella A flat, triangular bone at the front of the knee joint; the kneecap. penis The external reproductive organ of the male. pericardial sac The sac that surrounds the heart. perineum The pelvic floor and associated structures occupying the pelvic outlet, bounded anteriorly by the pubic symphysis, laterally by the ischial tuberosities, and posteriorly by the coccyx. periosteum Tough connective tissue that covers the bone. peripheral nervous system (PNS) A subdivision of the nervous system consisting of nerves and ganglia. phagocytosis The process by which cells ingest solid substances, such as other cells, bacteria, bits of necrosed tissue, and foreign particles. phalanges The bones of the fingers and toes. phospholipids A class of compounds, widely distributed in living cells, that contain phosphoric acid, fatty acids, and a nitrogenous base. pia mater The innermost layer of the meninges. It directly covers the brain. pituitary gland A small gland attached to the hypothalamus. It supplies numerous hormones that govern many vital processes. rectum The segment of the large intestine continuous with the descending sigmoid colon just proximal to the anal canal. plasma membrane The outer covering of a cell that contains the cellular cytoplasm; also known as the cell membrane. red marrow Specialized soft tissue found in many bones of infants and children; in the spongy bone of the proximal epiphyses of the humerus and femur; and in the sternum, ribs, and vertebral bodies of adults. It is essential in the manufacture of red blood cells. platelets Fragments of a cell. These initiate the clotting process. pleural cavity The area of the body that surrounds the lungs. pleural space The potential space between the visceral layer and the parietal layer of the pleura. polysaccharides Carbohydrates that contain three or more molecules of simple carbohydrate. pons The part of the brainstem between the medulla and the midbrain. portal vein A vein in the liver that conveys the blood to the inferior vena cava through the hepatic veins. posterior The back, or dorsal, surface. precapillary sphincters Smooth muscle sphincters that regulate blood flow through a capillary. prokaryotes Cells without a true nucleus; instead, nuclear material is scattered throughout the cytoplasm. prone A position in which the patient lies on the stomach (facedown). prostate gland The gland that lies just below the male bladder. Its secretion is one of the components of semen. puberty The period of life when the ability to reproduce begins. pubis One of a pair of pubic bones that, with the ischium and the ilium, form the hipbone and join the pubic bone from the opposite side at the pubic symphysis. pulmonary surfactant Certain lipoproteins that reduce the surface tension of pulmonary fluids, allowing the exchange of gases in the alveoli of the lungs and contributing to the elasticity of pulmonary tissue. pulmonary trunk The large elastic artery that carries blood from the right ventricle of the heart to the right and left pulmonary arteries. pulmonary veins The veins that carry oxygenated blood from the lung to the left atrium. pupil The opening in the center of the iris that regulates the amount of light entering the eye. Purkinje fibers Myocardial fibers that are a continuation of the bundle of His and that extend into the muscle walls of the ventricles. radius One of the bones of the forearm. It lies parallel to the ulna. renal pyramids Pyramidal masses seen on longitudinal section of the kidney. They contain part of the loop of Henle and the collecting tubules. respiration The process of the molecular exchange of oxygen and carbon dioxide in the body’s tissues. reticular activating system A functional system in the brain that is essential for wakefulness, attention, concentration, and introspection. reticular formation A small, thick cluster of neurons nestled in the brainstem that controls breathing, the heartbeat, blood pressure, level of consciousness, and other vital functions. retina The nervous tunic of the eye. It is continuous with the optic nerve. retroperitoneal Behind the peritoneum. ribonucleic acid (RNA) A nucleic acid found in the nucleus and the cytoplasm of cells that transmits genetic instructions from the nucleus to the cytoplasm. In the cytoplasm, RNA functions in the assembly of proteins. ribosomes The “factories” in cells, in which protein is synthesized. right atrium One of the four chambers of the human heart. It receives deoxygenated blood from the body through the venae cavae and pumps it into the right ventricle. sarcomere The contractile unit of skeletal muscle. It contains thick and thin myofilaments. sclera The opaque membrane covering the eyeball. scrotum The sac of skin that contains the testes. sebaceous glands Glands of the skin, usually associated with a hair follicle, that produce sebum. sebum The secretion of sebaceous glands. It prevents drying of the skin and protects against invasion by some bacteria. semen The male reproductive fluid. seminal vesicle One of two glandular structures that empty into the ejaculatory ducts. Its secretion is one of the components of semen. septum A thin wall dividing two cavities or masses of soft tissue. serum Blood plasma without its clotting factors. 197 short bones Bones that are approximately as broad as they are long, such as the carpal bones of the wrist and the tarsal bones of the ankle. sinoatrial node An area of specialized heart tissue that generates the cardiac electrical impulse. sinuses The cavities in the bones of the skull that connect to the nasal cavities by small channels. skeletal muscle Muscle tissue that appears microscopically to consist of striped myofibrils; also known as striated muscle and voluntary muscle. small intestine The longest portion of the digestive tract. It is divided into the duodenum, jejunum, and ileum. smooth muscle One of two kinds of muscle. It is composed of elongated, spindle-shaped cells in muscles not under voluntary control, such as smooth muscle of the intestines, stomach, and other visceral organs. Also known as visceral muscle, involuntary muscle, and nonstriated muscle. somatic nervous system The part of the nervous system composed of nerve fibers that send impulses from the central nervous system to skeletal muscle. somatomotor neurons Neurons that innervate skeletal muscles. spermatogenesis The process of development of spermatozoa. spermatozoa The male sex cells, which are composed of a head and a tail. Sperm contains genetic information transmitted by the male. spinal nerves Thirty-one pairs of nerves formed by the joining of the dorsal and ventral routes that arise from the spinal cord. spleen A large, highly vascular lymphatic organ situated in the upper part of the abdominal cavity between the stomach and the diaphragm. It responds to foreign substances in the blood, destroys worn-out erythrocytes, and is a storage site for red blood cells. sternal angle The point at which the manubrium joins the body of the sternum; also known as the angle of Louis. sternoclavicular joint The double gliding joint between the sternum and the clavicle. sternomanubrial joint The articulation between the upper two parts of the sternum, the manubrium and the sternal body. sternum The elongated, flattened bone that forms the middle portion of the thorax. subarachnoid space The area below the arachnoid membrane but above the pia mater that contains cerebrospinal fluid. subclavian vein The continuation of the axillary vein in the upper body. It extends from the lateral border of the 198 first rib to the sternal end of the clavicle, where it joins the internal jugular to form the brachiocephalic vein. subcutaneous tissue The adherent layer of adipose tissue just below the dermal layer; also known as the hypodermis. subdural space The space between the dura mater and the arachnoid. superior Situated above or higher than a point of reference in the anatomic position. superior vena cava The vein that returns blood from the head and neck, upper limbs, and thorax to the right atrium. supine A position in which the patient lies on the back (faceup). sweat glands Glands that produce sweat or viscous organic secretions; also known as sudoriferous glands. sympathetic nervous system A subdivision of the autonomic nervous system that usually is involved in preparing the body for physical activity. symphysis pubis The joint that connects the coxal bones of the pelvis. synapse Any junction between nerve cells and other nerve cells, muscle cells, gland cells, or sensory receptors. It serves to transmit action potentials from one cell to another. synovial joints Joints that are freely movable. system Interconnected functions or organs in which a stimulus or an action in one area affects all other areas. tarsal bones The bones of the ankle. taste buds The peripheral taste organs that are distributed over the tongue and the roof of the mouth. testes The male gonads, which produce the male sex cells, or sperm. thalamus Tissue located just above the hypothalamus. It helps to produce sensations, associates sensations with emotions, and plays a part in arousal. thymus A single, unpaired gland located in the mediastinum. The primary central gland of the lymphatic system. thyroid membrane The fibrous membrane that joins the hyoid and the thyroid cartilages. tibia The second longest bone of the skeleton. It is located at the medial side of the leg. tonsils Large collections of lymphatic tissue beneath the mucous membrane of the oral cavity and pharynx. trachea A cylindrical tube in the neck composed of cartilage and membrane. It conveys air to the lungs. tricuspid valve The valve located between the right atrium and the right ventricle. tunic One of the enveloping layers of a part; one of the coats of a blood vessel; one of the coats of the eye; one of the coats of the digestive tract. tympanic membrane The cellular membrane that separates the external ear from the middle ear; also known as the eardrum. ulna One of the bones of the forearm. ureters A pair of tubes that carry the urine from the kidneys into the bladder. urethra A small tubular structure that drains urine from the bladder. In men, it also serves as a passageway for semen during ejaculation. urinary bladder The muscular, membranous sac in the pelvis that stores urine for discharge through the urethra. uterine tubes A pair of ducts that open at one end into the uterus and at the other end into the peritoneal cavity, over the ovary; also known as the fallopian tubes. uterus The hollow, pear-shaped internal female organ of reproduction. uvula The cone-shaped process hanging down from the soft palate that helps prevent food and liquid from entering the nasal cavities. vagina The part of the female genitalia that forms a canal from the orifice through the vestibule to the uterine cervix. vascular tunic The choroid, ciliary body, and iris. ventral root The nerve that conveys efferent nerve processes away from the spinal cord. ventricles Small cavities; in the human systems context, this term usually refers to the right and left ventricles of the heart. viruses Minute, parasitic microorganisms without independent metabolic activity that can replicate only within a cell of a living plant or animal host. visceral peritoneum The serous membrane that covers the abdominal organs. visceral reflexes Reflexes mediated by autonomic nerves and initiated in the viscera. vitreous humor The transparent, jellylike material that fills the space between the lens and the retina of the eye. vocal cords The two folds of elastic ligaments covered by mucous membrane that stretch from the thyroid cartilage to the arytenoid cartilage. Vibration of the vocal cords is responsible for voice production; also known as the true vocal cords. vulva The external genitalia of the female. xiphoid process The smallest of three parts of the sternum. It articulates caudally with the body of the sternum and laterally with the seventh rib. yellow marrow Specialized soft tissue (mainly adipose) found in the compact bone of most adult epiphyses. Human anatomy is the study of how the human body is organized. The paramedic must know anatomy to assess a patient by body region. This knowledge also helps the paramedic communicate well with other members of the health care team. Anatomy Overview Understanding the relationship between human anatomy and normal body function is the center of all patient care. As professionals, paramedics must have knowledge of anatomy to educate their patients, to advocate for their patients’ health, and to ensure the most appropriate care is provided. Terminology To ensure that all health care providers have a common understanding of terminology, directional terms used by medical professionals refer to the human body © wavebreakmedia/Shutterstock. 199 Part 2 Anatomy and Physiology Midline RIGHT LEFT Proximal Superior Medial in the anatomic position. This position describes a person standing erect with the feet and palms facing the examiner. A patient in the supine position is lying on the back (faceup). A patient in the prone position is lying on the stomach (facedown). A patient in the lateral recumbent position is lying on the right or left side. Regardless of the patient’s specific position, the paramedic should always report patient information with reference to the anatomic position1 (FIGURE 10-1). Lateral 200 SHOW ME THE EVIDENCE Modified from: Lim D, Bartlett S, Horrocks P, Grant-Wakefield C, Kelly J, Tippett V. Enhancing paramedics procedural skills using a cadaveric model. BMC Med Educ. 2014;14:138. Directional terms, such as up or down, front or back, and right or left, also are expressed in anatomic terminology (TABLE 10-1). These terms always refer to the patient, not the examiner (eg, the patient’s left arm). Anatomic Planes The relationships of internal body structures are organized into anatomic planes. These planes may be viewed as imaginary straight-line divisions of the human body (FIGURE 10-2). The sagittal plane runs vertically through the middle of the body, creating right and left sections. A plane that is to one side of the midline is said to be parasagittal. The transverse (or horizontal) plane divides the body into top and bottom sections, known as superior and inferior sections. The frontal (or coronal) plane divides the body into front and back sections, known as anterior and posterior sections. Distal Inferior Medial Proximal Lateral In 2012, Lim and colleagues piloted a 3-hour human cadaver training workshop for second-year undergraduate paramedic students. The workshop aimed to provide the students with an opportunity to refine a range of procedural skills and to experience first-hand the differences in human anatomy compared to manikin-based simulation alone. A total of 114 students attended the workshop, and 96 evaluations were included in the analysis, representing a return rate of 84%. The researchers found statistically significant improvement in anatomic knowledge and improved confidence in performing procedural skills after the workshop. The researchers concluded that cadaver training provides an effective adjunct to simulated learning and clinical placements. Distal FIGURE 10-1 Anatomic position. A person in the anatomic position stands with the feet and the palms of the hands facing forward, with the thumbs to the outside. © Jones & Bartlett Learning. Body Regions The human body is divided into a number of regions,2 a division that helps to organize anatomic structures. The appendicular region consists of the limbs, or extremities. The axial region includes the head, neck, thorax, and abdomen. The abdomen usually is divided into four quadrants: right upper, right lower, left upper, and left lower (FIGURE 10-3). The dividing lines between the abdominal quadrants consist of two imaginary divisions, which run horizontally through the umbilicus and vertically from the xiphoid process through the symphysis pubis. Body Cavities The three major cavities of the human body are the thoracic cavity, the abdominal cavity, and the pelvic Chapter 10 Review of Human Systems 201 TABLE 10-1 Directional Terms Term Definition Left Toward the left side Right Toward the right side Superior Situated above another structure (usually synonymous with “cephalic”) Inferior Situated below another structure (usually synonymous with “caudal”) Cephalic Toward the head of the body Caudal Toward the distal end of the spine Proximal Closer than another structure to the point of attachment to the trunk Distal Farther than another structure from the point of attachment to the trunk Medial Toward the midline of the body Lateral Away from the midline of the body Anterior The front of the body (synonymous with “ventral”) Posterior The back of the body (synonymous with “dorsal”) Ventral Pertaining to the front Dorsal Pertaining to the back © Jones & Bartlett Learning. Longitudinal axis Lateral Medial Ventral Sagittal (lateral) plane Antero posterior axis Dorsal Lateral Horizontal (medio lateral axis Cranial Frontal (coronal) plane Costal arch Liver Spleen Stomach Gallbladder RUQ Transverse (axial) plane LUQ Umbilicus Iliac crest Cecum RLQ LLQ Appendix Small intestine Colon Inguinal ligament Rectum Pubic symphysis Caudal FIGURE 10-2 Body planes. FIGURE 10-3 Abdominal quadrants. © Jones & Bartlett Learning. © Jones & Bartlett Learning. 202 Part 2 Anatomy and Physiology cavity (FIGURE 10-4). The thoracic cavity is divided into two portions by a midline structure known as the mediastinum. The mediastinum includes the trachea, esophagus, thymus, heart, and great vessels. The lungs are located on either side of this midline structure. The thoracic cavity is surrounded by the rib cage and separated from the abdominal cavity by the diaphragm. The thorax contains two pleural cavities (which contain the lungs) and a pericardial cavity (which contains the heart). Each of these cavities is lined with a serous membrane. The visceral serous membrane comes in contact with the organ, whereas the parietal serous membrane comes in contact with the cavity wall. These membranes produce a thin, lubricating film of fluid; this fluid reduces the friction that occurs during movement of organs against other organs or body cavities. An imaginary plane divides the abdominal cavity from the pelvic cavity. In this plane, the division is drawn between the symphysis pubis and the sacral promontory—that is, the projecting portion of the pelvis at the base of the sacrum. The abdominal and pelvic cavities are lined with a thin sheet of membranous tissue that secretes serous fluid. The serous membrane that covers the abdominal organs is known as the visceral peritoneum; the serous membrane that covers the body cavity wall is known as the parietal peritoneum. Peritoneal organs are held in place at the body wall by a continuous organ called mesentery, which offers a pathway for nerves and vessels to reach the organs. The mesentery is also thought to play a role in regulating inflammation and coagulation pathways. Abdominopelvic organs behind the peritoneum are said to be retroperitoneal, DID YOU KNOW Historically, the mesentery was thought to be made up of fragmented, separate structures. Recent research, however, has shown that it is actually one continuous organ that reaches from the duodenum down to the rectum. Although its function is still unclear, studying the mesentery as a distinct organ may aid researchers in understanding dysfunction and diseases caused by problems with the mesentery. Modified from: Coffey JC, O’Leary DP. The mesentery: structure, function, and role in disease. Lancet Gastroenterol Hepatol. 2016;1(3):238-247. Cranial cavity Spinal cavity Dorsal body cavity Mediastinum Pleural cavity Pericardial cavity Diaphragm Thoracic cavity Ventral body cavity Abdominal cavity Pelvic cavity Abdominopelvic cavity FIGURE 10-4 Body cavities. The thoracic cavity includes the two pleural cavities and the pericardial cavity. The abdominopelvic cavity contains the abdominal cavity and the pelvic cavity. © Jones & Bartlett Learning. meaning behind the peritoneum. These organs include the kidneys, adrenal glands, pancreas, portions of the colon, and the urinary bladder. The pelvic cavity is enclosed by the bones of the pelvis. The abdominal and pelvic cavities often are referred to collectively as the peritoneal or abdominopelvic cavity. Cell Structure The cell is the basic unit of life. Cells are highly organized units composed of protoplasm, or living matter. The three main parts of all human cells are the cytoplasmic membrane (plasma membrane), cytoplasm, and nucleus. Cytoplasmic Membrane The cytoplasmic membrane encloses the cytoplasm and forms the outer boundary of the cell. The cytoplasmic membrane has two layers of phospholipids (phosphate-containing fat molecules), which form a fluid framework for the cytoplasmic membrane (FIGURE 10-5). Substances outside this membrane are labeled as either extracellular (outside of cells) or intercellular (between cells); substances inside the cytoplasmic membrane are termed intracellular. The functions of the cytoplasmic membrane are to Chapter 10 Review of Human Systems Phospholipid bilayer Golgi apparatus Internal membrane surface Mitochondrion 203 External membrane surface Carbohydrate chain Glycoprotein Glycolipid Protein Cytosol Cholesterol Nucleus Lysosome Rough endoplasmic reticulum Membrane channel protein Ribosome Smooth endoplasmic reticulum Plasma membrane FIGURE 10-5 Fluid mosaic model of the plasma membrane. © Jones & Bartlett Learning. enclose and support the cell contents and regulate what moves into and out of the cell. The central layer of the cytoplasmic membrane is a lipid bilayer—in other words, a layer composed of a double layer of lipid molecules. The lipid bilayer has a liquid quality, such that protein molecules “float” on the inner and outer surfaces. Some of these proteins have carbohydrate molecules bound to them. The protein molecules are thought to function as membrane channels, carrier molecules, receptor molecules, enzymes, or structural supports in the membrane (see Chapter 11, General Principles of Pathophysiology). Cytoplasm The cytoplasm lies between the cytoplasmic membrane and the nucleus. The nucleus is visible as a round or spherical structure in the center of the cell. Specialized structures in the cytoplasm, known as organelles, perform functions important to the cell’s survival (TABLE 10-2 and FIGURE 10-6). The endoplasmic reticulum is a chain of connecting sacs or canals that winds through the cytoplasm of the cell. In essence, the endoplasmic reticulum serves as a tiny circulatory system for the cell. The tubular passages or canals in the endoplasmic reticulum carry proteins and other substances through the cytoplasm of the cell from one area to another. The two types of endoplasmic reticulum are smooth endoplasmic reticulum and rough endoplasmic reticulum. Smooth endoplasmic reticulum is found in cells that handle or produce fatty substances, and it also plays a part in detoxification processes through the chemical action of enzymes. Rough endoplasmic reticulum is found in cells that produce proteins to be secreted for use outside the cell. Ribosomes are the “factories” in the cells where protein is synthesized. These macromolecules consist of protein and ribonucleic acid (RNA) and are composed of thousands of atoms. Ribosomes usually are bound to the endoplasmic reticulum but also are found free in cytoplasm. They form complexes with strands of RNA, which provides the blueprint for the new protein through its contents, the body’s genetic code. To form the new proteins, individual amino acids are attached in long chains via peptide bonds. The Golgi apparatus concentrates and packages materials (including proteins) for secretion from the cell. This organelle consists of tiny sacs composed of smooth endoplasmic reticulum, which are stacked one on top of the other near the nucleus. The Golgi apparatus sometimes chemically modifies proteins by synthesizing and attaching carbohydrate molecules to the proteins to form glycoproteins or by attaching lipids to the proteins to form lipoproteins. 204 Part 2 Anatomy and Physiology TABLE 10-2 Major Cell Structures and Their Functions Structure Function Centrioles Play a role in cell reproduction. Cilia Short, hairlike extensions on the free surfaces of some cells capable of movement. Endoplasmic reticulum Ribosomes attached to rough endoplasmic reticulum synthesize proteins; smooth endoplasmic reticulum synthesizes lipids and certain carbohydrates. Flagella Single projections of cell surfaces that are much larger than cilia; the only example in human beings is the “tail” of a sperm cell. Golgi apparatus Synthesizes carbohydrates, combines them with proteins, and packages the product as globules of glycoproteins. Lysosomes The “digestive system” of the cell. Mitochondria Synthesize adenosine triphosphate; the “powerhouses” of the cell. Nucleoli Play an essential role in the formation of ribosomes. Nucleus Dictates protein synthesis, thereby playing an essential role in other cell activities—namely, active transport, metabolism, growth, and heredity. Plasma membrane Serves as the boundary of the cell. Protein and carbohydrate molecules on the outer surface of the plasma membrane perform various functions; for example, they serve as markers that identify the cells of each individual or as receptor molecules for certain hormones. Ribosomes Synthesize proteins; the “protein factories” of the cell. © Jones & Bartlett Learning. Centriole Mitochondrion Lysosome Vacuole Plasma membrane Nuclear membrane Nucleus Nucleolus Chromatin Ribosomes Glycogen Cytoplasm Golgi apparatus Smooth endoplasmic reticulum Rough endoplasmic reticulum Intermediate filament Microtubule Microfilaments FIGURE 10-6 Structure of a cell. © Jones & Bartlett Learning. Chapter 10 Review of Human Systems These concentrated globules move slowly outward to and through the cell membrane. At this point, the globules break open and spill their contents. Mucus is an example of a product of the Golgi apparatus. Lysosomes are membranous-walled organelles that contain enzymes, which enable them to function as intracellular digestive systems. For example, some enzymes digest nucleic acids, proteins, polysaccharides, and lipids. Certain white blood cells (leukocytes) have large numbers of lysosomes that contain enzymes to digest engulfed bacteria. If tissues are damaged, these powerful enzymes may escape from ruptured lysosome sacs into the cytoplasm, where they digest both damaged and healthy cells. Lysosomes also digest organelles of cells that are no longer functional, a process called autophagia. The mitochondria are the “power plants” of the cell. These organelles, which are found throughout the cell, serve as the site of aerobic oxidation. In the mitochondria, energy derived from the efficient metabolism of nutrients and oxygen via the Krebs cycle (further described in Chapter 11, General Principles of Pathophysiology) is used to synthesize high-energy triphosphate bonds, such as adenosine triphosphate (ATP). These triphosphate bonds are the energy source for the muscles, nerves, and overall function of the body. CRITICAL THINKING A patient has severe lung disease and poor oxygenation. What effect will this have on cellular energy production? Centrioles are paired, rod-shaped organelles that lie at right angles to each other in a specialized zone of the cytoplasm known as the centrosome. Each centriole is composed of microtubules, which play an important role in the process of cell division. Nucleus At some point in their existence, all human cells contain a nucleus, in which the genetic material of the cell is located. The nucleus is a large, membrane-bound organelle that ultimately controls all other organelles in the cytoplasm. The nucleus may be spherical, elongated, or lobed, depending on the type of cell in which it is found. The nucleus usually is located near the center of the cell; however, some cells, such as red blood cells (erythrocytes), lose their nucleus as they develop. Other cells, such as certain bone cells, have 205 more than one nucleus. The most significant feature for categorizing cells is the presence or absence of a nucleus. The cell nucleus is surrounded by a nuclear membrane, which encloses the nucleoplasm. The nucleoplasm contains a number of specialized structures, including the nucleolus and the chromatin granules. The nucleolus consists of deoxyribonucleic acid (DNA), which contains the genetic blueprint for the body’s RNA, and protein, which makes ribosomes. These ribosomes ultimately migrate through the nuclear membrane into the cytoplasm of the cell and produce proteins. Chromatin granules are threadlike structures DID YOU KNOW? Human Genome Project October 1, 2015, marked the 25th anniversary of the launch of the Human Genome Project (HGP), which was completed in 2003. The HGP has led to the discovery of more than 1,800 disease-related genes and more than 2,000 genetic tests for human conditions. The original goals of the project were the following: • Identify all of the approximately 20,000 to 25,000 genes found in human DNA. • Determine the sequences of the three billion chemical base pairs that make up human DNA. • Store this information in databases. • Improve tools for data analysis. • Transfer related technologies to the private sector. • Address the ethical, legal, and social issues (ELSI) that might arise from the project. A genome is all the DNA in an organism, including its genes. Genes carry information for making all the proteins required by all organisms. These proteins determine, among other things, how the organism looks, how well its body metabolizes food or fights infection, and sometimes even how it behaves. Knowledge of the effects of DNA variations among people may lead to revolutionary new ways to diagnose, treat, and perhaps prevent some of the thousands of disorders that affect human beings. Besides providing clues to understanding human biology, learning about nonhuman DNA sequences or organisms can lead to an understanding of their natural capabilities. This knowledge can then be applied to solving challenges in health care, agriculture, energy production, environmental remediation, and carbon sequestration. Modified from: Human Genome Project. US Department of Health and Human Services, National Institutes of Health, website. https://report.nih.gov/NIHfactsheets/ViewFactSheet. aspx?csid=45&key=H#H. Updated March 29, 2013. Accessed December 26, 2017. 206 Part 2 Anatomy and Physiology made up of proteins and DNA. During cell division, the chromatin condenses to form the 23 pairs of chromosomes characteristic of human cells. The information in nuclear DNA determines most of the chemical events that occur within the cell. The basic functions of the nucleus are cell division and control of genetic information. Not all cells are capable of continuous division, and some cells (eg, nerve cells) cannot reproduce. Major Classes of Cells Free-living cells of multicellular “social” organisms are divided into two major classes based on the organization of their genetic material. The two main types of cells are eukaryotes (“true nucleus”) and prokaryotes (“before nucleus”). Eukaryotes are larger than prokaryotes, have a more extensive intracellular anatomy, and have a separate membrane-bound nucleus that holds the genetic material (chromosomes, DNA). The fluid filling eukaryotic cells is divided into the nucleoplasm (inside the nuclear membrane) and the cytoplasm (outside the nuclear membrane). Nearly all human body cells are eukaryotes, as are those of most living organisms. Exceptions are bacteria, cyanobacteria (blue-green algae), and mycoplasmas, which are prokaryotes; bacteria and mycoplasmas cause many diseases in human beings and other animals. Viruses have a close association with cells but are not classified as cells. In prokaryotic cells, the genetic material and enzymes required for energy production, cell growth, and cell division are contained in the jellylike cytoplasm, which in turn is surrounded by the plasma membrane. Unlike eukaryotes, these cells have a simple internal organization. Prokaryotes do not have a nucleus that is bound by a plasma membrane, and their DNA is attached to the plasma membrane. Chief Cellular Functions Cells have evolved in myriad ways to fulfill specific tasks in the human body. Through differentiation (maturation), cells become specialized in one type of function or act in concert with other cells to perform a more complex task. (Stem cells—a class of undifferentiated cells that are able to differentiate into any kind of specialized cell types—are discussed in BOX 10-1.) For example, red blood cells carry out only one function: They transport respiratory gases around the body. In contrast, the cells in the pancreas synthesize and secrete large amounts of the digestive enzymes required to break down foods. The seven chief cellular functions are as follows: 1. 2. 3. 4. 5. 6. 7. Movement (muscle cells) Conductivity (nerve cells) Metabolic absorption (kidney and intestinal cells) Secretion (mucous gland cells) Excretion (all cells) Respiration (all cells) Reproduction (most cells) Cell Reproduction All human cells, with the exception of reproductive (sex) cells, reproduce by mitosis. In this process, cells divide to multiply; one cell divides to form two cells. Many cell types in the body (eg, epithelial, liver, and BOX 10-1 Stem Cells: A Brief Overview Stem cells come from two main sources: embryonic stem cells and adult stem cells. Research involving the use of embryonic stem cells is controversial, as it involves the destruction of human embryos. Less controversial sources of acquiring stem cells include using cells from adults, amniotic fluid and membrane, the umbilical cord, breast milk, and bone marrow. These methods do not raise the same kinds of legal, religious, moral, and ethical concerns that arise with embryonic stem cell research—but stem cells from those sources also do not have the same potential as embryonic stem cells to develop into specialized cell types. At present, the most widely used stem cell–based therapy is bone marrow transplantation, which is used to treat blood cancers such as leukemia and lymphoma. Modified from: Stem cells: what they are and what they do. Mayo Clinic website. http://www.mayoclinic.org/tests-procedures/stem-cell -transplant/in-depth/stem-cells/ART-20048117. Published March 23, 2013. Accessed December 26, 2017; Stem cell information: stem cell basics. US Department of Health and Human Services, National Institutes of Health website. https:// stemcells.nih.gov/info/basics.htm. Accessed June 27, 2017. Chapter 10 Review of Human Systems bone marrow cells) undergo cell division throughout a person’s life. Other cell types (eg, nerve and skeletal muscle cells) divide until near the time of birth, but no longer divide in the extrauterine human. Body Tissues The characteristics of cell structure and composition are used to classify tissue types. Four main types of tissue make up the many organs of the body: epithelial tissue, connective tissue, muscle tissue, and nervous tissue. CRITICAL THINKING Think about the role of each of the tissue types. Compare these roles with the types of materials used to construct a building. How does each tissue type serve as a component for building a body? Epithelial Tissue Epithelial tissue covers surfaces or forms structures derived from body surfaces (eg, glands). This tissue consists almost entirely of cells that have little or no intercellular material between them. It forms continuous sheets that contain no blood vessels. Epithelium covers the outside of the body and also lines the digestive tract, the blood ves