Organ Systems Overview PDF

2 E X E R C I S E Organ Systems Overview Learning Outcomes Go to Mast...

2 E X E R C I S E Organ Systems Overview Learning Outcomes Go to Mastering A&P™ > Study Area to improve your performance ▶▶ Name the human organ systems, and indicate the major functions of each. in A&P Lab. ▶▶ List several major organs of each system, and identify them in a dissected rat, human cadaver or cadaver image, or a dissectible human torso model. ▶▶ Name the correct organ system for each organ when presented with a list of organs. Instructors may assign these and other Pre-Lab Pre-Lab Quiz Quiz questions using Mastering A&P™ 1. Name the structural and functional unit of all living things. _________ 2. The small intestine is an example of a(n) _________, because it is > Lab Tools > Practice Anatomy Lab composed of two or more tissue types that perform a particular > Anatomical Models function for the body. Instructors may assign new a. epithelial tissue Building Vocabulary coaching b. muscular tissue activities, Pre-Lab Quiz questions, c. organ Art Labeling activities, Practice d. organ system Anatomy Lab Practical questions (PAL), 3. The ______________ system is responsible for ensuring fluid and and more using the Mastering A&P™ electrolyte homeostasis within the body. Item Library. 4. The caecum is a part of the ______________ system. 5. The thin muscle that separates the thoracic and abdominal cavities is the ______________. Materials ▶▶ Freshly killed or preserved rat (predissected by instructor as a T demonstration or for student dissection he basic unit of life is the cell. Cells fall into four different categories accord- [one rat for every two to four students]) ing to their structures and functions. These categories correspond to the four or predissected human cadaver primary tissue types: epithelial, muscular, nervous, and connective. A tissue is ▶▶ Dissection trays a group of cells that are similar in structure and function. An organ is a structure ▶▶ Twine or large dissecting pins composed of two or more tissue types that performs a specific function for the body. ▶▶ Scissors An organ system is a group of organs that act together to perform a particular ▶▶ Probes body function. For example, the organs of the digestive system work together to break down foods and absorb the end products into the bloodstream in order to ▶▶ Forceps provide nutrients and fuel for all the body’s cells. In all, there are 11 organ systems, ▶▶ Disposable gloves described in Table 2.1 on p. 34. ▶▶ Human torso model (dissectible) Read through this summary of the body’s organ systems (Table 2.1) before beginning your rat dissection or examination of the predissected human cadaver. If a human cadaver is not available, Figures 2.3 to 2.6 will serve as a partial replacement. 33 M02_MARI2259_12_GE_C02.indd 33 29/06/2022 16:09  34 Exercise 2 Table 2.1 Overview of Organ Systems of the Body Organ system Major component organs Function Integumentary Skin, hair, and nails; Protects deeper organs from mechanical, chemical, and bacterial injury, and cutaneous sense organs and glands from drying out Excretes salts and urea Aids in regulation of body temperature Produces vitamin D Skeletal Bones, cartilages, tendons, Body support and protection of internal organs 2 ligaments, and joints Provides levers for muscular action Cavities provide a site for blood cell formation Bones store minerals Muscular Muscles attached to the skeleton Primary function is to contract or shorten; in doing so, skeletal muscles allow locomotion (running, walking, etc.), grasping and manipulation of the environment, and facial expression Generates heat Nervous Brain, spinal cord, nerves, and Allows body to detect changes in its internal and external environment and to sensory receptors respond to such information by activating appropriate muscles or glands Helps maintain homeostasis of the body via rapid transmission of electrical signals Endocrine Pituitary, thymus, thyroid, Helps maintain body homeostasis, promotes growth and development; parathyroid, adrenal, and pineal produces chemical messengers called hormones that travel in the blood to glands; ovaries, testes, and pancreas exert their effect(s) on various target organs of the body Cardiovascular Heart and blood vessels Primarily a transport system that carries blood containing oxygen, carbon dioxide, nutrients, wastes, ions, hormones, and other substances to and from the tissue cells where exchanges are made; blood is propelled through the blood vessels by the pumping action of the heart Antibodies and other protein molecules in the blood protect the body Lymphatic Lymphatic vessels, lymph nodes, Picks up fluid leaked from the blood vessels and returns it to the blood spleen, and thymus Cleanses blood of pathogens and other debris Houses lymphocytes that act via the immune response to protect the body from foreign substances Respiratory Nasal cavity, pharynx, larynx, Keeps the blood continuously supplied with oxygen while removing carbon trachea, bronchi, and lungs dioxide Contributes to the acid-base balance of the blood Digestive Oral cavity, pharynx, esophagus, Breaks down ingested foods to smaller particles, which can be absorbed into stomach, small and large intestines, and the blood for delivery to the body cells accessory structures including teeth, Undigested residue removed from the body as feces salivary glands, liver, and pancreas Urinary Kidneys, ureters, bladder, and Rids the body of nitrogen-containing wastes including urea, uric acid, and urethra ammonia, which result from the breakdown of proteins and nucleic acids Maintains water, electrolyte, and acid-base balance of blood Reproductive Male: testes, prostate gland, scrotum, Provides gametes called sperm for perpetuation of the species penis, and duct system, which carries sperm to the body exterior Female: ovaries, uterine tubes, uterus, Provides gametes called eggs; the uterus houses the developing fetus until mammary glands, and vagina birth; mammary glands provide nutrition for the infant DISSECTION AND IDENTIFICATION The Organ Systems of the Rat Many of the external and internal structures of the rat are to s­uperficial observations of a previously dissected human quite similar in structure and function to those of the human. cadaver. The general instructions for observing external struc- So, a study of the gross anatomy of the rat should help you tures also apply to human cadaver observations. The photo- understand our anatomy. The following instructions include graphs in Figures 2.3 to 2.6 will provide visual aids. directions for dissecting and observing a rat. In addition, Note that four organ systems (integumentary, skeletal, the descriptions of the organs (Activity 4, Examining the muscular, and nervous) will not be studied at this time, because Ventral Body Cavity, which begins on p. 36) also apply they require microscopic study or more detailed dissection. M02_MARI2259_12_GE_C02.indd 34 29/06/2022 16:09  Organ Systems Overview 35 Activity 1 Activity 2 Observing External Structures Examining the Oral Cavity 1. If your instructor has provided a predissected rat, go to the Examine the structures of the oral cavity. Identify the teeth and demonstration area to make your observations. Alternatively, if tongue. Observe the extent of the hard palate (the portion you and/or members of your group will be dissecting the speci- underlain by bone) and the soft palate (immediately posterior men, obtain a preserved or freshly killed rat, a dissecting tray, to the hard palate, with no bony support). Notice that the pos- dissecting pins or twine, scissors, probe, forceps, and dispos- terior end of the oral cavity leads into the throat, or pharynx, a able gloves, and bring them to your laboratory bench. passageway used by both the digestive and respiratory systems. 2 If a predissected human cadaver is available, obtain a probe, forceps, and disposable gloves before going to the demonstration area. Activity 3 2. Don the gloves before beginning your observations. ! This precaution is particularly important when handling Opening the Ventral Body Cavity freshly killed animals, which may harbor pathogens. 1. Pin the animal to the wax of the dissecting tray by placing its 3. Observe the major divisions of the body—head, trunk, and dorsal side down and securing its extremities to the wax with extremities. If you are examining a rat, compare these divisions large dissecting pins as shown in Figure 2.1a. to those of humans. Text continues on next page ➔ (a) (b) Figure 2.1 Rat dissection: Securing for dissection and the initial incision. (a) Securing the rat to the dissection tray with dissecting pins. (b) Using scissors to make the incision on the median line of the abdominal region. (c) Completed incision from the pelvic region to the lower jaw. (d) Reflection (folding back) of the skin to expose the underlying muscles. (c) (d) M02_MARI2259_12_GE_C02.indd 35 29/06/2022 16:09  36 Exercise 2 2. Lift the abdominal skin with a forceps, and cut through it with the scissors (Figure 2.1b). Close the scissor blades, and insert them flat under the cut skin. Moving in a cephalad direction, open and close the blades to loosen the skin from the underlying connective tissue and muscle. Now, cut the skin along the body midline, from the pubic region to the lower jaw (Figure 2.1c). Finally, make a lateral cut about halfway down the ventral surface of each limb. Complete the job of freeing the skin with the scissor tips, and pin the flaps to the tray 2 (Figure 2.1d). The underlying tissue that is now exposed is the skeletal musculature of the body wall and limbs. Notice that the muscles are packaged in sheets of pearly white connec- tive tissue (fascia), which protect the muscles and bind them together. 3. Carefully cut through the muscles of the abdominal wall in the pubic region, avoiding the underlying organs. Now, hold and lift the muscle layer with a forceps and cut through the muscle layer from the pubic region to the bottom of the rib cage. Make two lateral cuts at the base of the rib cage (Figure 2.2). A thin membrane attached to the inferior bound- ary of the rib cage should be obvious; this is the diaphragm, which separates the thoracic and abdominal cavities. Cut the diaphragm where it attaches to the ventral ribs to loosen the rib cage. Cut through the rib cage on either side. You can now lift the ribs to view the contents of the thoracic cavity. Cut across the flap, at the level of the neck, and remove the Figure 2.2 Rat dissection. Making lateral cuts at the base rib cage. of the rib cage. Activity 4 Examining the Ventral Body Cavity 1. Starting with the most superficial structures and work- To expose the esophagus, push the trachea to one side. ing deeper, examine the structures of the thoracic cavity. Esophagus: A food chute; the part of the digestive system Refer to Figure 2.3 as you work. Choose the appropriate that transports food from the pharynx (throat) to the stomach. view depending on whether you are examining a rat (a) or a human cadaver (b). Diaphragm: A thin muscle attached to the inferior boundary of the rib cage. Thymus: An irregular mass of glandular tissue overlying the heart (not illustrated in the human cadaver photograph). Follow the esophagus through the diaphragm to its junction with the stomach. With the probe, push the thymus to the side to view the heart. Stomach: A curved organ important in food digestion and Heart: Medial oval structure enclosed within the pericardium temporary food storage. (serous membrane). 2. Examine the superficial structures of the abdominopelvic Lungs: Lateral to the heart on either side. ­cavity. Lift the greater omentum, an extension of the perito- Now observe the throat region to identify the trachea. neum (serous membrane) that covers the abdominal viscera. Continuing from the stomach, trace the rest of the digestive tract Trachea: Tubelike “windpipe” running medially down the (Figure 2.4, p. 38). throat; part of the respiratory system. Small intestine: Connected to the stomach and ending just Follow the trachea into the thoracic cavity; notice where it before the saclike cecum. divides into two branches. These are the bronchi. Large intestine: A large muscular tube connected to the small Bronchi: Two passageways that plunge laterally into the tissue intestine and ending at the anus. of the two lungs. Text continues on page 38. ➔ M02_MARI2259_12_GE_C02.indd 36 29/06/2022 16:09  Organ Systems Overview 37 2 Trachea Thymus Heart Lung Diaphragm Liver (a) Trachea Superior vena cava Pericardium (cut and reflected) Lungs Heart Diaphragm (b) Figure 2.3 Superficial organs of the thoracic cavity. (a) Dissected rat. Instructors may assign this figure as an Art (b) Human cadaver. Labeling Activity using Mastering A&P™ M02_MARI2259_12_GE_C02.indd 37 29/06/2022 16:09  38 Exercise 2 Falciform ligament Liver Stomach 2 Spleen Greater omentum Small intestine Large intestine Urinary bladder Cecum (a) (b) Figure 2.4 Abdominal organs. (a) Dissected rat, superficial view. Instructors may assign this figure as an Art (b) Human cadaver, superficial view. Labeling Activity using Mastering A&P™ Cecum: The initial portion of the large intestine. Examine the posterior wall of the abdominal cavity to locate the two kidneys (Figure 2.5). Follow the course of the large intestine to the rectum, which is partially covered by the urinary bladder (Figure 2.5). Kidneys: Bean-shaped organs; retroperitoneal (behind the ­peritoneum). Rectum: Terminal part of the large intestine; continuous with the anal canal. Adrenal glands: Large endocrine glands that sit on top of each kidney; considered part of the endocrine system. Anus: The opening of the digestive tract (through the anal canal) to the exterior. Carefully strip away part of the peritoneum with forceps and attempt to follow the course of one of the ureters to Now lift the small intestine with the forceps to view the m ­ esentery. the bladder. Mesentery: An apronlike serous membrane; suspends many Ureter: Tube running from the indented region of a kidney to of the digestive organs in the abdominal cavity. Notice that it the urinary bladder. is heavily invested with blood vessels and, more likely than not, riddled with large fat deposits. Urinary bladder: The sac that serves as a reservoir for urine. Locate the remaining abdominal structures. 4. In the midline of the body cavity lying between the kidneys are the two principal abdominal blood vessels: Pancreas: A diffuse gland; rests dorsal to and in the mesentery between the first portion of the small intestine and the stom- Inferior vena cava: The large vein that returns blood to the ach. You will need to lift the stomach to view the pancreas. heart from the lower body regions. Spleen: A dark red organ curving around the left lateral side Descending aorta: Deep to the inferior vena cava; the largest of the stomach; an organ of the lymphatic system, it is often artery of the body; carries blood away from the heart. called the red blood cell “graveyard.” 5. You will perform only a brief examination of reproductive Liver: Large and brownish red; the most superior organ in the organs. If you are working with a rat, first determine if the abdominal cavity, directly beneath the diaphragm. animal is a male or female. Observe the ventral body surface beneath the tail. If a saclike scrotum and an opening for the 3. To locate the deeper structures of the abdominopelvic anus are visible, the animal is a male. If three body openings— cavity, move the stomach and the intestines to one side urethral, vaginal, and anal—are present, it is a female. with the probe. M02_MARI2259_12_GE_C02.indd 38 29/06/2022 16:09  Organ Systems Overview 39 Inferior vena cava Adrenal gland Kidney Descending aorta 2 Ureters Seminal gland Urinary bladder Prostate Bulbo-urethral gland Ductus deferens Penis Testis Rectum (a) Scrotum Anus (b) Adrenal gland Kidney Descending aorta Ureter Ovary Uterine horns Uterus Urinary bladder Vagina Figure 2.5 Deep structures of the Urethral opening abdominopelvic cavity. (a) Human cadaver. Vaginal orifice (b) Dissected male rat. (Some reproductive Anus structures also shown.) (c) Dissected female rat. (Some reproductive structures also shown.) (c) Male Rat Female Rat Make a shallow incision into the scrotum. Loosen and lift Inspect the pelvic cavity to identify the Y-shaped uterus lying out one oval testis. Exert a gentle pull on the testis to iden- against the dorsal body wall and superior to the bladder tify the slender ductus deferens, or vas deferens, which (Figure 2.5c). Follow one of the uterine horns superiorly to carries sperm from the testis superiorly into the abdominal identify an ovary, a small oval structure at the end of the uter- cavity and joins with the urethra. The urethra runs through ine horn. (The rat uterus is quite different from the uterus of a the penis and carries both urine and sperm out of the body. human female, which is a single-chambered organ about the Identify the penis, extending from the bladder to the ventral size and shape of a pear.) The inferior undivided part of the rat body wall. Figure 2.5b indicates other glands of the male uterus is continuous with the vagina, which leads to the body rat’s reproductive system, but they need not be identified exterior. Identify the vaginal orifice (external vaginal opening). at this time. Text continues on next page ➔ M02_MARI2259_12_GE_C02.indd 39 29/06/2022 16:09  40 Exercise 2 Large intestine Ureter Seminal gland Ductus deferens Bladder 2 Pubis Prostate Penis Testis (a) (b) Figure 2.6 Human reproductive organs. (a) Male external genitalia. (b) Sagittal section of the male pelvis. Large intestine (c) Sagittal section of the female pelvis. End of uterine tube Male Cadaver Ovary Make a shallow incision into the scrotum (Figure 2.6a). Loosen and lift out the oval testis. Exert a gentle pull on the testis to identify the slender ductus (vas) deferens, which Uterus carries sperm from the testis superiorly into the abdominopel- vic cavity and joins with the urethra (Figure 2.6b). The urethra Bladder runs through the penis and carries both urine and sperm out Pubis of the body. Identify the penis, extending from the bladder to Vagina the ventral body wall. External Female Cadaver opening of vagina Inspect the pelvic cavity to identify the pear-shaped uterus lying against the dorsal body wall and superior to the blad- der. Follow one of the uterine tubes superiorly to identify an (c) ovary, a small oval structure at the end of the uterine tube (Figure 2.6c). The inferior part of the uterus is continuous with the vagina, which leads to the body exterior. Identify the vaginal orifice (external vaginal opening). 6. When you have finished your observations, rewrap or store the dissection animal or cadaver according to your instructor’s directions. Wash the dissecting tools and equipment with labo- ratory detergent. Dispose of the gloves as instructed. Activity 5 Examining the Human Torso Model Examine a human torso model to identify the organs listed. Large intestine Spleen Check off the boxes as you locate the organs. Some model Liver Stomach organs will have to be removed to see the deeper organs. Lungs Thyroid gland Adrenal gland Esophagus Mesentery Trachea Aortic arch Heart Pancreas Ureters Brain Inferior vena cava Small intestine Urinary bladder Diaphragm Kidneys M02_MARI2259_12_GE_C02.indd 40 29/06/2022 16:09  Instructors may assign a portion 2 of the Review Sheet questions using Mastering A&P™ REVIEW SHEET E X E R C I S E Organ Systems Overview Name _______________________________________________________ Lab Time/Date_____________________________________ 1. Label each of the organs at the end of the supplied leader lines. 2. Name the organ system to which each of the following sets of organs or body structures belongs. 1. thymus, spleen, lymphatic vessels 5. epidermis, dermis, cutaneous sense organs 2. bones, cartilages, tendons 6. testis, prostate 3. pancreas, pituitary gland 7. liver, large intestine, rectum 4. trachea, bronchi, lungs 8. kidneys, ureter, urethra 41 M02_MARI2259_12_GE_C02.indd 41 29/06/2022 16:09  42 Review Sheet 2 3. Name the cells that are produced by the testes and ovaries. _________________________________________________________ ____________________________________________________________________________________________________________ 4. List the four primary tissue types. _______________________________________________________________________________ ____________________________________________________________________________________________________________ 5. Explain why an artery is an organ. _______________________________________________________________________________ ____________________________________________________________________________________________________________ 6. Where do the digestive and respiratory structures interact? What name is given to this region? __________________________ ____________________________________________________________________________________________________________ ____________________________________________________________________________________________________________ ____________________________________________________________________________________________________________ 7. What organs are responsible for the absorption of nutrients? How are they adapted to this role? _________________________ ____________________________________________________________________________________________________________ 8. + During anesthesia, a patient’s muscular system is disabled. Why must a doctor carefully monitor a patient’s temperature in this case? ___________________________________________________________________________________________________ ____________________________________________________________________________________________________________ 9. + The mother of a child scheduled to receive a thymectomy (removal of the thymus gland) asks you whether there will be any side effects from the removal of the gland. Which two organ systems would you mention in your explanation? ____________________________________________________________________________________________________________ ____________________________________________________________________________________________________________ 10. + Individuals with asplenia are missing their spleen or have a spleen that doesn’t function well. It is recommended that these patients talk to their doctor about vaccines that are indicated for their health condition. Explain how this recommendation ­correlates to their chronic health condition. _______________________________________________________________________ ____________________________________________________________________________________________________________ ____________________________________________________________________________________________________________ M02_MARI2259_12_GE_C02.indd 42 29/06/2022 16:09