Bio 325 – Midterm 1 Notes

An Introduction to the Human Body Objectives After completing this chapter, you should be able to 1. define the terms anatomy and physiology. 2. define the following levels of structural organization: chemical, cellular, tissue, organ, system and organism. 3. identify the 11 systems of the human body, list representative organs of each system, and describe the major functions of each system. 4. identify the basic life processes of the human body. 5. define the term homeostasis, and explain the effects of stress on homeostasis. 6. describe the components of a feedback system. 7. compare the operation of negative and positive feedback systems. 8. explain the relationship between homeostasis and disease. 9. describe the anatomical position, and compare common and anatomical terms used to describe various regions of the human body. e the terms describing directions and anatomical planes used in association with the human body. , by name and location, the principal body cavities and the organs contained within them. Keywords and Topics Make certain that you can define, and use in context, each of the terms listed below, and that you understand the significance of each of the concepts. 1. Define the terms anatomy and physiology. A. Anatomy – the science of the body structures and the relationships among them (ana = up, tomy = cutting) B. Dissection –the careful cutting apart of body structures to study their relationships (dis=apart, section=act of cutting) C. Physiology – the science of body functions – how the body works (physio = nature, logy = study of) 2. Define the following levels of structural organization: chemical, cellular, tissue, organ, system, and organism. A. chemical level I. atom – smallest unit of matter that participate in chemical reactions II. molecule – two or more atoms joined together B. cellular level I. cell – molecules form cells which are the basic structural and functional units of an organism that are composed of chemicals C. tissue level I. tissue – are groups of cells and the materials surrounding them that work together to perform a particular function D. organ level I. organ –composed of two or more tissues, they have specific functions and recognizable shapes E. system level I. system – consists of related organs with a common function F. organismal level I. organism—all the parts of the human body functioning together Chemical level (letter)—includes atoms and molecules (two atoms joined together) examples are C, H, O, N, Ca, S, molecules are DNA or glucose Cellular level (word)—molecules combine to form cells (smallest living unit of the human body) examples are muscle cells, nerve cells, epithelial cells Tissue level (sentence)—are groups of cells and the material around them that work together to perform a particular function. Examples are epithelial tissue (covers body surfaces, lines hollow organs and cavities and forms glands), connective tissue (connects, supports, and protects body organs while distributing blood vessels to other tissues), muscle tissue (contracts to make body parts move and generates heat), and nervous tissue (carries information from one part of the body to another through nerve impulses) Organ level (paragraphs)—different types of tissues are joined together (organs are structures composed of two or more types of tissues, they have specific functions and recognizable shapes). System level (chapters)—consists of related organs with a common function. Sometimes an organ can be part of more than one system (ex: pancreas is a part of the digestive system and the endocrine system) Organismal level (book)—all the parts of the human body functioning together. 3. Identify the 11 systems of the human body, list representative organs of each system, and describe the major functions of each system. A. systems: integumentary—components are skin, hair, nails, sweat and oil glands. Function is protecting body, help regulate temperature, eliminates some waste, helps make vit d, detects sensations such as pain, touch, warmth and cold, stores fat and provides insulation skeletal—components are bones and joints and cartilages. Function is to support and protect body, provides surface area for muscles to attach, aids body movements, houses cells that produce blood cells, stores minerals and lipids. Muscular—components are skeletal muscle tissue (usually attached to bones). Function is body movements (ex walking), maintains posture and produces heat Nervous—components are the brain spinal cord, nerves and special sense organs like eyes and ears. Function is to generate action potentials to regulate body activates, detect changes in body’s internal and external environments, interprets changes and responds by causing muscular contractions or glandular secretions. Endocrine—components are hormone producing glands (ex pineal gland, hypothalamus, thyroid gland, pituitary gland, thymus, parathyroid gland, adrenal glands, pancreas, ovaries and testes, as well as hormone­producing cells in several other organs. Functions are to regulate body activities by releasing hormones (chemical messengers transported in blood from endocrine glad or tissue to target organ. Cardiovascular—components are blood, heart, and blood vessels. Function that heart pumps blood through vessels, blood carries O2 and nutrients to cells and CO2 and wastes away from cells and helps regulate acid­base balance, temperature, and water content of body fluids, blood components help defend against disease and repair damaged blood vessels. Lymphatic—components are lymphatic fluid and vessels, spleen, thymus, lymph nodes and tonsils, cells that carry out immune responses (b cells, t cells and others). Function is to return proteins and fluid to blood, carry lipids from gastrointestinal tract to blood, contains sites of maturations and proliferations of b cells and t cells that protect against disease­causing microbes. Respiratory—components are lungs and air pathways (ex pharynx throat, larynx voice box, trachea windpipe, and bronchial tubes leading into and out of lungs. Function is to transfer oxygen from inhaled air to blood and co2 from blood to exhaled air, helps regulates acid­base balance of body fluids, air flowing out of lungs though vocal cords produce sound. Digestive—components are organs of gastrointestinal tract, a long tube that includes the moth, pharynx, esophagus, stomach, small and large intestines and anus. It also includes accessory organs that assist in digestive process such as salivary glands, liver, gallbladders, and pancreas. Function is to achieve physical and chemical breakdown of food, absorb nutrients, eliminate solid wastes. Urinary—Kidneys, ureters, urinary bladder and urethra. Function is to produce, store and eliminate urine, eliminate wastes and regulate volume and chemical composition of blood. Also, to help maintain the acid­base balance of body fluids, maintains body’s mineral balance, helps regulate production of red blood cells. Reproductive—gonads (testes in males and ovaries in females), associated organs (uterine tubes/fallopian tubes, uterus, vagina, and mammary glands in females and epididymis, ductus or vas deferens, seminal vesicles, prostate and penis in males. Function is for gonads to produce gametes (sperm or oocytes) that unite to form a new organism. Gonads also release hormones that regulate reproduction and other body processes. Associated organs transport and store gametes. Mammary glands produce milk. Note: Learn the major components and functions for each system. 4. Define the basic life processes of the human body. A. Metabolism – the sum of all chemical process that occur in the body I. Catabolism – (catabol= throwing down) the breakdown of complex chemical substances into simper components (ex splitting proteins in food into amino acids) II. Anabolism – (anabol = a raising up) the building up of complex chemical substances from small simpler components (using amino acids to anabolize (build) new proteins that make up body structure such as muscles and bones) B. Responsiveness—is the body’s ability to detect and respond to changes (ex: an increase in body temperature during fever is a change in the internal environments, turning your head towards sounds of brakes is response to external environment. Different cells respond in different ways—nerve cells generate electrical signals (action potentials), while muscles cells respond by contracting—making body parts move. C. Movement—includes motion of the whole body, individual organs, single cells and even tiny structure inside cells. Ex: after you eat fats your gallbladder contracts and releases bile into the gastrointestinal tract to help digest them. Or when body tissue is damaged or infected certain white blood cells move the bloodstream into the affected tissue to help clean up and repair the area. Inside cells, vesicles move around to carry out their functions. D. Growth—is an increase in body size that results from an increase in the size of existing cells, an increase in number of cells or both. Sometimes increase in tissue size occurs because of the amount of material between cells ex is growing bones, which has an accumulation up of mineral deposits between bone cells causing bone to grown in length and width. E. Differentiation—is the development of a cell from an unspecialized to a specialized state. Such as precursor cells, which can divide and give rise to cells that undergo differentiation, those are known as stem cells. Each type of cell in the body has a specializes structure or function that differed from that of its precursor cell (ex red blood cells and some white blood cells all arise from same precursor cells in red bone marrow. Or fertilized human egg (ovum) develops into an embryo, then fetus, infant, child, adult. I. stem cells F. Reproduction—is either the formation of new cells for tissue growth, repair or replacements, OR the production of a new individual. The formations of new cells occur through cell division. The production of a new individual occurs through the fertilization of an ovum by a sperm cell to forma zygote – followed by repeated cell divisions and the differentiation of these cells. G. Autopsy—“seeing with one’s own eyes” I. Necropsy—is a postmortem examination of the body and dissection of its internal organs to confirm cause of death. It can uncover diseases, extent of injuries, and explain how those things contributed to death. Can provide more information about diseases etc., and reveal conditions that may affect offspring. Helps in legal ways too­criminal cases and beneficiaries. 5. Define the term homeostasis, and explain the effects of stress on homeostasis. A. Homeostasis – is the condition of equilibrium in the body’s internal environments due to the constant interactions of the body’s many regulatory processes. It is dynamic. Each structure from the cellular level to the system level contributes in some way to keep the internal environment within normal limits. B. body fluids – dilute, watery solutions containing dissolved chemicals I. intracellular fluid (ICF) – fluid within cells (body’s internal environment) II. extracellular fluid (ECF) – fluid outside body cells a. interstitial fluid = internal environment (ECF that fills narrow spaces between cells of tissues) b. blood plasma (ECF within blood vessels) c. lymph (ECF within lymphatic vessels) d. cerebrospinal fluid (ECF in and around the brain and spinal cord) e. synovial fluid (ECF in joints) f. aqueous humor (ECF of the eyes) g. vitreous body (ECF of the eyes) 6. Describe the components of a feedback system. A. control of homeostasis; nerve impulses and hormones—homeostasis is continually being disturbed ex heat in summer, lack of o2 on a run (external), blood glucose levels fall too low when you skip breakfast (internal enviro). Most of the time its mild but can be intense and prolonged. Body can bring itself back to balance—via the nervous system and endocrine system working together or independently. Nervous system regulates homeo by sending nerve impulse (ap) to organs that can counteract changes from the balances state. The endocrine system glands secrete messenger molecules called hormones into the blood. Nerve changes are rapid, hormones are slower (usually working via negative feedback systems). B. feedback system (feedback loop – is a cycle of event in which the status of a body condition is monitored, evaluated, changed, remonitored, reevaluated and so on); controlled condition (each monitored variable ei body temp, blood pressure, blood glucose is termed controlled condition); stimulus (disruption that changes a controlled condition). C. receptor (a body structure that monitors changes in a controlled condition and sends input to a control center); afferent pathway (info carried toward control centre); input (typically in the form of nerve impulses or chemical signals) D. control center (ex brain – sets range of values within which a controlled condition should be maintained—evaluates the input from receptors and generates output commands when needed); output (from the control centre, typically occurs as nerve impulses or chemical signals, or hormones); efferent pathway (since info flows away from control centre) E. effector (brings about a change) is a body structure that receives output from the control center and produces a response or effect that changes the controlled center; response (that alters the controlled condition) EXAMPLE: When your body temperature drops sharply, your brain (control center) sends nerve impulses (output) to your skeletal muscles (effectors). The result is shivering, which generates heat and raises body temp